By: Andraxxus
- 3rd October 2016 at 11:37Permalink- Edited 1st January 1970 at 01:00
The F-16 uses a pitot intake. If you don't understand the difference between a fixed ramp and pitot I can't help you. I suppose an inlet cone is also pitot by that reckoning?
Inlet cone is also a fixed inlet if the cone itself doesn't move to match the shocks.
One oblique shock and one normal is all you need a low supersonic speeds. If you have more than needed in terms of ramps for a given airspeed, it often reduces intake efficiency. See F-15 intake below M1.0 vs Pitot. There is no good reason for a fighter to have variable geometry given 99.9999% of its lifetime operating speeds.
Go tell that to MiG, Sukhoi, Boeing etc engineers. Latest F-15E variants, Su-35 MiG-35 are still built with ramps, they must be wasting their time.
The M2.35 is likely correct given that DA2 exceeded M2.0 with RB199s, which are higher BPR and not at all optimised for high altitude of high speed. On the same page you'll also find analysis as to why M2.35 is much more likely.
You are basing your assumptions on a "likely" which isn't shared by the manufacturer.
M2.0 is also a little too rounded don't you think?
No I don't think so, just like I don't find M2.5 limit of F-15 "too rounded" to claim it is "likely" to be M2,67 or something...
How is the Austrian AF half official?
AF statements do make mistakes, and sometimes they are too negligent to check&update their website. The very fact that German UK and Austrian airforces give different numbers for exact same aircraft should at least make you question a little bit.
On some regards Official military websites DO give erroneous information. A particular Sovremenny destroyer Russian Navy website claims as operational doesn't even have a engine inside it.
Actually you don't because car manufacturers are well known for not always stating accurate hp and torque figures. Some under claim, some over claim. Same deal with top speed and acceleration. And I think I only need to mention the VW emissions scandal in passing to make a point.
Ah but there are reasons for it. too much hp&torque = more taxes & insurance costs, less buyers. too little hp and torque = underpowered vehicle, less buyers. But I don't recall any car that has "underrated" top speed or acceleration. Because faster is always better, and no one will inflate their emissions, because higher emissions is always a bad thing (both for environment and for taxes).
The MiG-25 could do Mach 3.2+. It achieved M3.21 and 126,000ft in testing if I remember correctly. It was restricted to M2.83 because the HPT was inclined to warp above that speed.
Well, that is frankly irrelevant. its airframe + engine limit is M2,83. Given the cold enough air like -15 or so, I am 100.00% sure a Su-27 can do M2,5+ without any modifications, but its not safe at all, an sure as hell this is not its top speed.
MiG-25 has too much exess thrust at around M2,83 but that only helps it to overcome the additional drag comes from payloads, so it could still fly at M2,7 with 4x500kg bombs.. This doesn't make its top speed a tad faster than M2.83.
You sure about the F-15 only managing M2.25?
Yes. PW-100 engined like I've said. Without Vmax of course, meaning no 102% trim. Risking destruction of engines is not exacly an apples to apples comparison with Su-27.
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Though you reposted a graph probably either me or poster Eagle first posted on this forum, I thank you that it perfectly proved my point that no F-15A/C/E can reach M2.5 on level flight at standard day, despite M2.5 is often quoted as its top speed. Kind of proving my point that M2.35, even if it may be true, may only be the top limit speed but not the actual top speed...
M1.25 is cited in the referenced book but yes it should be 1,530kph at SAE. Nope the M1.25 is direct quote from a book cited on wiki, 1,470kph is some a55clown on wiki doing an ad-hoc conversion.
A book printed in 2002, giving info for an aircraft introduced into service in 2003. We are in 2016 and that book contradicts with everything else that doesn't quote it as source. Great one.
SC definitely does have a bearing because it demonstrated how well the Typhoon operates in its M0.9-M1.6 optimised regime. I see the MiG-29 is struggling to crack M1.0 on dry thrust, wow, the Typhoon's engines must be performing much better in that regime.
Speaking of DRY thrust, it obviously have far greater supersonic T-D. It doesn't show anything else about optimisation or anything you spit on this forum. For the 13049134th time you are comparing an two different engines, in a flight regime one engine simply isn't designed for.
Nope because MiG-25 is optimised for high altitude and it slower at low altitude, its climb is also affected by weight.
But its way faster at high altitudes, so climb rates at upper half of the envelope must be better? Funny to see you claim superior performance based on top speed, then get back to real world to type some "excuses" when your "proof" can lead to much more interesting conclusions.
I'm well aware of that but nevertheless the way you phrased it was incorrect. A plane doing M0.9 cannot be climbing at 345m/s.
"Climbing" does not equate to "climb rate". I didn't say how fast it could climb, I've asked for your explaination about a given "climb rate". Don't try to twist this as well.
I didn't say anything was impossible, I said they couldn't climb as fast as a Typhoon. No way, no how.
Ah I thought we were talking about climb rate. For climbing to an altitude/speed point, I've *PROVED* an F-16 (with not THAT spectacular climb or acceleration performance) can quite match (or exceed) both
"Brakes-off to supersonic acceleration: <30 s"
"Brakes-off to Mach 1.6 at 11,000 m (36,000 ft): <150 s"
Too lazy to quote myself, did the calculation in the past, a forum search would do it. Or better, don't take my word for it, sum up the values yourself; here's the relevant pages I am reposting:
You don't have to do a guess work for optimal climb&acceleration path. Just accelerate to M0,9 @ S/L, climb to 30k feet then accelerate to M1,6. This rather oversimplified flight path will still yield quite interesting results.
Well let's see.
1. You failed to recognise that the Typhoon had a ramp intake and then claimed it was the same as an F-16 pitot intake when proved wrong (in this very post).
Well, I still don't see it as a ramp intake. In way-too-much laymans terms, ramp moves itself as such to make oblique shock "seal" the inlet. By doing so, when that shock expands, the "inlet side" of the shock has higher than atmospheric pressure but an exact M1.0 speed. If the oblique shock doesn't align with the inlet area air still slows down, but for pressure recovery its not exactly useful.
Ramp intake = F-14/15 Su-27 MiG-25/29/31 etc etc.
Splitter plate, aircraft's nose, wings, canopy rudders, even F-18's LERX all cause oblique shocks. Otherwise calling a splitter plate an inlet ramp is simply WRONG even if a Dr. Engineer from Chrysler Aerospace claims as such.
If splittler plate is considered a "fixed ramp", then F-16/18C, Rafale, B-1B etc all have fixed ramps.
I didn't argue with your point because it did not matter.
Su-27 has variable inlet ramps with M2.35 top speed. Su-34 really did have a fixed inlet ramp (that is ramps welded in a certain angle) and its top speed is M1,8.
Exact same thing applies to B-1A -> B-1B, Su-24A -> Su-24B and some tornado variants, even F-14D.
2. Earlier you failed to know the difference between total pressure and static pressure.
You were talking about stagnation pressure, when you kept calling it "total" pressure. It did not matter in any case, because "dynamic" part of stagnation pressure is necessarily fixed by the intake velocity demanded by the engine. If its M0,6 it has to be at M0,6. So the actual variable on that part is the static pressure.
I didn't bother going on with that discussion because P01 and P02 are arbitrary points. What is 01 and what is 02? If *I* were to name those in an inlet analysis, 0 would be atmospheric, 01 and 02 would represent pressures after shock#1 and shock#2. Its definately not so in your case, and its up to your source to properly mention WHAT those numbers represent.
3. You claimed the pressure in an intake couldn't exceed atmospheric unless it was variable geometry.
Show me it can? Better yet, provide an dynamic Thrust data for ANY aircraft that has a fixed inlet, yet has impressive enough thrust to prove Typhoon *may* have good enough T/W at supersonic?
Never said the manuals were wrong, but dry thrust still demonstrates how well the engine and airframe is operating at low supersonic speeds.
Your comment is as idiotic as claiming painting the aircraft gray demonstrates how fast the aircraft is.
If the flow in the nozzle is choked in convergent configuration, then it must go to con-di.
IF being the appropirate word there. Again neither you or I have info about that. But mk1 eyeball observation.
Typhoon: idle = nozzles expanded. pilot increases thrust for take off:
First, nozzles close, then they start to expand, then afterburners lit. This early expension tells us (me at least) flow becomes supersonic after some point inside dry thrust.
MiG-29: idle = nozzles expanded just like Typhoon. Pilot increases thrust:
Nozzles close, remain closed as we see black smoke increase, then afterburner is lit and right at the same time nozzles start to expand. This tells us nozzles work in convergent on whole dry thrust regime and only con-di at wet thrust.
Now thrust is not only about velocity it has a pressure component as well, and skin friction and shocks from the body of the aircraft actually slow the air to quite subsonic esspecially near M1.0 airspeeds (that is why its called transonic), so MiG-29 can go a tad above M1.0 (M1.04 to be exact).
Well if the RD-33 and intakes and MiG-29 T-D are so great how come it can't supercruise? Just because of the nozzles? Give me a break. Fitted variable geometry intake but didn't fit correct nozzles to supercruise?
I don't know I didn't design RD-33. I would suspect however, not "just because" of nozzles. It has to provide sufficent velocity or pressure on DRY thrust at first to allow a nozzle converge enough so it can generate supersonic thrust. Without changing the design of engine itself, a simple nozzle modification won't give supercruise ability.
As for T-D, I've never claimed MiG-29's drag to be lower than Typhoon at supersonic regime. For all I know, MiG-29 is designed primarily for subsonic high manuevebility, and Typhoon is for supersonic. It would be very stupid to claim Typhoon would have higher drag at supersonic than MiG-29; about as stupid as claiming Typhoon would have less drag than Su-27/MiG-29/F-16 etc at subsonic, esspecially at lower altitudes. I still think MiG-29 would have greater T/W due to greater WET thrust, but much even greater drag would *probably* hinder it supersonic. Same goes for Su-27 which you were originally comparing.
You were making up horse**** based on "superior T/W" magic. I've shown MiG-29 has way greater T/W on some parts of envelope. At the very least, I've PROVED uninstalled thrust can NEVER be a basis of thrust comparison between aircraft. Nothing more nothing less. You could have accepted this like a man, but you immediately twisted your argument to Climb rate.
That didn't make sense, climb rate is still best before wavedrag and around M0,85-M0,9 is subsonic, part of envelope MiG-29 will have similar or less drag and a higher thrust than Typhoon. Then, again instead of accepting this, you twisted your argument to top speed and supercruise.
In that area you could have sticked to manufacturer data, but you couldn't do it because it didn't fit your propoganda. Instead, you took your one top speed from Austrian airforce which could easily be an error on web designer's part because NO ONE ELSE claims as such, and second (sea level) top speed you quote a source, who quotes 2002 book of "llustrated Directory of Fighters by Mike Spick". Quoting an 2002 book is esspecially funny for an aircraft entered into service in 2003..
Su-35 has greater thrust than Su-27 yet manufacturerer says it is slower. That is good enough for me. Typhoon manufacturer says Typhoon is slower than MiG-29, and that is also good enough for me. I don't care at all if that isn't good enough for you, if you have to nitpick something else that says faster, just to prove yours is bigger in a pissing contest, that is your own inferiority complexity to deal with.
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By: Starfish Prime
- 3rd October 2016 at 13:37Permalink- Edited 1st January 1970 at 01:00
Inlet cone is also a fixed inlet if the cone itself doesn't move to match the shocks.
Go tell that to MiG, Sukhoi, Boeing etc engineers. Latest F-15E variants, Su-35 MiG-35 are still built with ramps, they must be wasting their time.
You are basing your assumptions on a "likely" which isn't shared by the manufacturer.
No I don't think so, just like I don't find M2.5 limit of F-15 "too rounded" to claim it is "likely" to be M2,67 or something...
AF statements do make mistakes, and sometimes they are too negligent to check&update their website. The very fact that German UK and Austrian airforces give different numbers for exact same aircraft should at least make you question a little bit.
On some regards Official military websites DO give erroneous information. A particular Sovremenny destroyer Russian Navy website claims as operational doesn't even have a engine inside it.
Ah but there are reasons for it. too much hp&torque = more taxes & insurance costs, less buyers. too little hp and torque = underpowered vehicle, less buyers. But I don't recall any car that has "underrated" top speed or acceleration. Because faster is always better, and no one will inflate their emissions, because higher emissions is always a bad thing (both for environment and for taxes).
Well, that is frankly irrelevant. its airframe + engine limit is M2,83. Given the cold enough air like -15 or so, I am 100.00% sure a Su-27 can do M2,5+ without any modifications, but its not safe at all, an sure as hell this is not its top speed.
MiG-25 has too much exess thrust at around M2,83 but that only helps it to overcome the additional drag comes from payloads, so it could still fly at M2,7 with 4x500kg bombs.. This doesn't make its top speed a tad faster than M2.83.
Yes. PW-100 engined like I've said. Without Vmax of course, meaning no 102% trim. Risking destruction of engines is not exacly an apples to apples comparison with Su-27.
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Though you reposted a graph probably either me or poster Eagle first posted on this forum, I thank you that it perfectly proved my point that no F-15A/C/E can reach M2.5 on level flight at standard day, despite M2.5 is often quoted as its top speed. Kind of proving my point that M2.35, even if it may be true, may only be the top limit speed but not the actual top speed...
A book printed in 2002, giving info for an aircraft introduced into service in 2003. We are in 2016 and that book contradicts with everything else that doesn't quote it as source. Great one.
Speaking of DRY thrust, it obviously have far greater supersonic T-D. It doesn't show anything else about optimisation or anything you spit on this forum. For the 13049134th time you are comparing an two different engines, in a flight regime one engine simply isn't designed for.
But its way faster at high altitudes, so climb rates at upper half of the envelope must be better? Funny to see you claim superior performance based on top speed, then get back to real world to type some "excuses" when your "proof" can lead to much more interesting conclusions.
"Climbing" does not equate to "climb rate". I didn't say how fast it could climb, I've asked for your explaination about a given "climb rate". Don't try to twist this as well.
Ah I thought we were talking about climb rate. For climbing to an altitude/speed point, I've *PROVED* an F-16 (with not THAT spectacular climb or acceleration performance) can quite match (or exceed) both
"Brakes-off to supersonic acceleration: <30 s"
"Brakes-off to Mach 1.6 at 11,000 m (36,000 ft): <150 s"
Too lazy to quote myself, did the calculation in the past, a forum search would do it. Or better, don't take my word for it, sum up the values yourself; here's the relevant pages I am reposting:
You don't have to do a guess work for optimal climb&acceleration path. Just accelerate to M0,9 @ S/L, climb to 30k feet then accelerate to M1,6. This rather oversimplified flight path will still yield quite interesting results.
Well, I still don't see it as a ramp intake. In way-too-much laymans terms, ramp moves itself as such to make oblique shock "seal" the inlet. By doing so, when that shock expands, the "inlet side" of the shock has higher than atmospheric pressure but an exact M1.0 speed. If the oblique shock doesn't align with the inlet area air still slows down, but for pressure recovery its not exactly useful.
Ramp intake = F-14/15 Su-27 MiG-25/29/31 etc etc.
Splitter plate, aircraft's nose, wings, canopy rudders, even F-18's LERX all cause oblique shocks. Otherwise calling a splitter plate an inlet ramp is simply WRONG even if a Dr. Engineer from Chrysler Aerospace claims as such.
If splittler plate is considered a "fixed ramp", then F-16/18C, Rafale, B-1B etc all have fixed ramps.
I didn't argue with your point because it did not matter.
Su-27 has variable inlet ramps with M2.35 top speed. Su-34 really did have a fixed inlet ramp (that is ramps welded in a certain angle) and its top speed is M1,8.
Exact same thing applies to B-1A -> B-1B, Su-24A -> Su-24B and some tornado variants, even F-14D.
You were talking about stagnation pressure, when you kept calling it "total" pressure. It did not matter in any case, because "dynamic" part of stagnation pressure is necessarily fixed by the intake velocity demanded by the engine. If its M0,6 it has to be at M0,6. So the actual variable on that part is the static pressure.
I didn't bother going on with that discussion because P01 and P02 are arbitrary points. What is 01 and what is 02? If *I* were to name those in an inlet analysis, 0 would be atmospheric, 01 and 02 would represent pressures after shock#1 and shock#2. Its definately not so in your case, and its up to your source to properly mention WHAT those numbers represent.
Show me it can? Better yet, provide an dynamic Thrust data for ANY aircraft that has a fixed inlet, yet has impressive enough thrust to prove Typhoon *may* have good enough T/W at supersonic?
Your comment is as idiotic as claiming painting the aircraft gray demonstrates how fast the aircraft is.
IF being the appropirate word there. Again neither you or I have info about that. But mk1 eyeball observation.
Typhoon: idle = nozzles expanded. pilot increases thrust for take off:
First, nozzles close, then they start to expand, then afterburners lit. This early expension tells us (me at least) flow becomes supersonic after some point inside dry thrust.
MiG-29: idle = nozzles expanded just like Typhoon. Pilot increases thrust:
Nozzles close, remain closed as we see black smoke increase, then afterburner is lit and right at the same time nozzles start to expand. This tells us nozzles work in convergent on whole dry thrust regime and only con-di at wet thrust.
Now thrust is not only about velocity it has a pressure component as well, and skin friction and shocks from the body of the aircraft actually slow the air to quite subsonic esspecially near M1.0 airspeeds (that is why its called transonic), so MiG-29 can go a tad above M1.0 (M1.04 to be exact).
I don't know I didn't design RD-33. I would suspect however, not "just because" of nozzles. It has to provide sufficent velocity or pressure on DRY thrust at first to allow a nozzle converge enough so it can generate supersonic thrust. Without changing the design of engine itself, a simple nozzle modification won't give supercruise ability.
As for T-D, I've never claimed MiG-29's drag to be lower than Typhoon at supersonic regime. For all I know, MiG-29 is designed primarily for subsonic high manuevebility, and Typhoon is for supersonic. It would be very stupid to claim Typhoon would have higher drag at supersonic than MiG-29; about as stupid as claiming Typhoon would have less drag than Su-27/MiG-29/F-16 etc at subsonic, esspecially at lower altitudes.
You were making up horse**** based on "superior T/W" magic. I've shown MiG-29 has way greater T/W on some parts of envelope. At the very least, I've PROVED uninstalled thrust can NEVER be a basis of thrust comparison between aircraft. Nothing more nothing less. You could have accepted this like a man, but you immediately twisted your argument to Climb rate.
That didn't make sense, climb rate is still best before wavedrag and around M0,85-M0,9 is subsonic, part of envelope MiG-29 will have similar or less drag and a higher thrust than Typhoon. Then, again instead of accepting this, you twisted your argument to top speed and supercruise.
In that area you could have sticked to manufacturer data, but you couldn't do it because it didn't fit your propoganda. Instead, you took your one top speed from Austrian airforce which could easily be an error on web designer's part because NO ONE ELSE claims as such, and second (sea level) top speed you quote a source, who quotes 2002 book of "llustrated Directory of Fighters by Mike Spick". Quoting an 2002 book is esspecially funny for an aircraft entered into service in 2003..
Su-35 has greater thrust than Su-27 yet manufacturerer says it is slower. That is good enough for me. Typhoon manufacturer says Typhoon is slower than MiG-29, and that is also good enough for me. I don't care at all if that isn't good enough for you, if you have to nitpick something else that says faster, just to prove yours is bigger in a pissing contest, that is your own inferiority complexity to deal with.
Yes but it still produces an oblique shock before the normal shock, which is far superior to a normal shock. This is aerodynamics 101, there's no way you have a degree, show me evidence.
F-22 isn't, F-35 isn't, EF isn't, Rafale isn't, Gripen isn't, J-20 isn't, PAK-FA probably isn't. Get the picture.
Actually it is, BAE states 1,522mph, EADS stated M2+. M2.0 only came up due to lifetime durability consideration of the air frame material. It was never a T-D limit.
F-15 was stated at M2.5+. F-22 as 'Mach 2 class'.
Operational norms for different air forces differ.
Not at all, all the vehicles I'm thinking of are top brackets for road tax and insurance.
Top speed is always quoted clean and in the remit we're discussing (climb rate), it's the T-D trend that's important, not the actual structural integrity.
Well the other trim figures are for short of 100%, so I would argue the 102% trim is the most valid. And it's not necessary it would risk the engines. Adding a little more fuel to the reheat does not risk the crucial core components at all.
Once again, the flight manuals are always 100%. Data is very often estimated. Eagles have gone over M2.5 in practice.
Like what? The performance data would have been well known by that time.
Surely the MiG-29's variable geometry intakes should help in supercruise, yet the Typhoon still manages 50% more. How embarrassing.
Idiotic analogy. The MiG-29 and Typhoon weigh the same. The MiG-25 weighs far more and has a much lower TWR. High altitude climb rate does not equal low altitude peak climb rate. Up there the air is thin and being able to fly faster produces more lift.
You're the one twisting it Mr. 'Fixed ramps are the same as pitot'. Given that the subject was peak climb rate, you should have said SEP, if you wished to distinguish between the two. In the context at hand, the sentence was wrong.
Haha, depends on what weights and configurations we look at.
Okay I'll bite, your SL acceleration table starts at 200kts. So you can add at least 12s to all those times. The HL acceleration table is also at the wrong altitude. But starting at basic aircraft weight of 20,168lb, 30,000lb GW (DI=0), gives up the closest match on fuel fraction (32.X% for both a/c). Extrapolation, that puts the 200kts to M0.91 time at 24.5s, so add 12s for 0-200kts and you have 36.5s, this also still excludes the altitude change during lift off and landing gear raise. Now begins the climb. 70s for 35,000ft. and 80s for climb to 40,000ft, so ~72s for climb to 36,000ft. That puts us at 108.5s. Extrapolate between 28,000lb and 32,000lb and we get 75s for M0.91-M1.62. Giving at total of 183.5s, or just under 3 minutes, so Typhoon is >33.5s faster.
In fact, even if the Tyhoon starts at rest and the F-16C starts at 200kts, the Typhoon still gets to M1.6 at 36,000ft >20s quicker. Nice example. Ooooh, and BTW, you do know the top speed of the F-16C is M2.05. Still doubt that M2.35 and that whole >M2.0 thing?
A ramp will create an oblique shock. This will not slow down air to subsonic, it slows it down to a lower supersonic Mach number, following which a normal shock slows it to subsonic. The deceleration to subsonic is always via a normal shock regardless of the intake, however if you do it from a very high Mach number, you lose a lot of total pressure and it's inefficient. If you apply 1 or more oblique shocks first it's more efficient. Now a variable ramp will allow you to optimise your oblique shock, and two will allow you to optimise 2 oblique shocks etc. there's ultimately no limit except weight and complexity. However a fixed ramp will still produce an oblique shock but it will only be the optimal oblique shock at one speed. However, it will still be better than a pitot's 1 normal shock at any supersonic speed. By setting the fixed ramp for M1.3-M1.4, you can produce as near as damnit, the same performance at variable geometry up to M1.6 and several % better than pitot.
The Typhoon is not calling the splitter plate a fixed ramp.
Well it kind of did matter because you used a graph I posted showing total pressure ratio across two inlets to suggest that the MiG's intake was superior because it increased pressure. Total pressure never increases in an inlet. P01 is the start of the intake, P02 is at the face of the engine. It is the part of the intake after the normal shock that slows air down to whatever the engine is designed for.
You really need me to prove something that is even present on RAM Air induction equipped sportsbikes?
I'm shaking my head at this stage. You really have a degree.
Not really, it makes perfect sense in demonstrating the relationship between drag and thrust at low to intermediate supersonic speeds.
Well I'm not going to look, but if that's the case it's a very crap design and I struggle to believe the designers would be so stupid as to only have the con-di operational on reheat.
Well you were claiming the MiG-29 had a higher peak sustained climb rate, which is achieved at low supersonic speeds. So if you agree the Typhoon has lower drag supersonic and higher thrust, plus the same weight, it stands to reason that the Typhoon can beat it on climb rate.
You haven't shown jack, because we don't have thrust vs velocity graphs for the EJ200, but we do know they're optmised for M0.9-M1.6. Because it obviously applies to climb rate. What is climb rate about if not TWR and drag?
Surely to achieve a climb rate (actual, not SEP) of 345m/s, it needs to be going supersonic, no? When Western sources quote climb rate, they mean actual climb rate, sustained at a given point, not a measure of SEP.
Well using your own data I've shown a Typhoon to reach 36,000ft and M1.6 much quicker than an F-16C, which can do M2.05. Enough said.
By: FBW
- 3rd October 2016 at 14:57Permalink- Edited 1st January 1970 at 01:00
Once again, the flight manuals are always 100%. Data is very often estimated. Eagles have gone over M2.5 in practice.
No, they haven't and flight manuals are not "estimated" at all. They are based on actual test flights on specific dates, which are noted on the pages. You are using manufacturer data, information off particular service pages which is often estimated and frequently incorrect. No F-15 could "in practice" achieve close to mach 2.5 without using the v-max augmentation which could damage the engines. Second, no armed F-15 could approach mach 2.5, making the stated top speed theoretical at best.
By: Andraxxus
- 3rd October 2016 at 18:35Permalink- Edited 1st January 1970 at 01:00
Yes but it still produces an oblique shock before the normal shock, which is far superior to a normal shock. This is aerodynamics 101, there's no way you have a degree, show me evidence.
Well I won't show a ****, not only because I don't see any reason to prove my degree to you, but also because I use same nickname in all websites I visit, and the present state of the country I am living in makes me would prefer to be anonymous.
My bachelors degree diploma has a big color logo of the university in the background and tiny golden logos as the texture of it. In my graduation year less than 15 people were graduated. I have already said I am currently master student at the same university and my thesis is related to aerodynamics. There are less than 5 masters degree students in mechanical engineering department and currently only myself is writing an aerodynamic related thesis.
My IP is already enough to reveal my city and district. If I also reveal my school, I would be openly revealing myself, even if hide my name. I wouldn't want to wake up with police at my door just because I may have insulted a politican years ago or wrote an inconvinient post here & there, just to prove myself to you, thanks. I could have easily faked a degree here, but instead, I write my reasons. If my word is not good enough nothing ever will be.
F-22 isn't, F-35 isn't, EF isn't, Rafale isn't, Gripen isn't, J-20 isn't, PAK-FA probably isn't. Get the picture.
Oh I got the picture pretty well. Other than your claim regarding "EF" none of these aircraft claim M2.0+ top speeds.
F-22 can be an exception because it simply has great thrust, but surely it won't be as fast as F-15 it replaces, PAK-FA is limited by materials but it does have a variable inlet ramps.
M2.0 only came up due to lifetime durability consideration of the air frame material. It was never a T-D limit.
Do you think M2.35 limit of MiG-29 or Su-27 came for other reasons? ALL limits came from durability reasons. Aerodynamically, MiG-29 can sustain 10-11Gs indefinately. But its still a 9G fighter. Given a little cold air both MiG-29 and Su-27 will easily pass M2.35. But durability prevents even M2.35 speeds for F-15 Su-27 or MiG-29 to be used indefinately.
F-15 was stated at M2.5+. F-22 as 'Mach 2 class'.
Ah kind of my point. You are right. F-15 was many times stated "M2.5 class" or "M2.5+"
Yet M2.5 is its top speed limit, and its top actual speed is M2,25 for PW-100, M2,45 for PW-220, and M2,3 for PW-229. So "M2,5 class" or "M2,5" doesn't mean a s***.
Operational norms for different air forces differ.
So if a RAF Typhoon races with an Austrian Typhoon latter will win?
it's the T-D trend that's important, not the actual structural integrity.
Ah I agree on that 100%. Then why bother with top speeds? Again, in your analogy, you are saying "M2.5+ F-15A is faster than M2.35 Su-27S, so it must have less drag, greater excess power and greater maneuverability".
Fact is F-15 isn't faster than Su-27, but some basic analysis will say its still less draggy when supersonic. Greater excess power and maneuverability is unbelievably dependent on altitude, attempted G, and airspeed, but generally at higher altitudes Su-27 is better at subsonic and high supersonic, and F-15 is better high transonic and low-mid supersonic speeds.
Lessons learned. 1-Such top speed claims are likely to be wrong. 2-Top speed doesn't reveal which aircraft is draggy and which is not.
Well the other trim figures are for short of 100%, so I would argue the 102% trim is the most valid. And it's not necessary it would risk the engines. Adding a little more fuel to the reheat does not risk the crucial core components at all.
Well, no suprise you would be wrong again. 102% is Vmax graph. The large graph (obviously) is routine operations graph. With manual saying "Use of Vmax switch is strictly prohibited", I wouldn't say its comperable to normal operations of Su-27's AL-31F. I could post the longer version from the manual about what Vmax does and after its use, how aircraft spends days inside the hangar with engines outside the aircraft, half dismantled perhaps.
Surely the MiG-29's variable geometry intakes should help in supercruise, yet the Typhoon still manages 50% more. How embarrassing.
Only embarrassing thing is you fail to grasp the fact MiG-29's engine is not designed for supercruising. You claim yourself an engineer, I don't understand how mentally retarded one needs to be to keep making this claim.
If I were to make same analogy as you do, your Typhoon cannot even do M2.5 yet MiG-25 with its huge weight and puny T/W can go 25+% faster.
You're the one twisting it Mr. 'Fixed ramps are the same as pitot'.
Well my very first post was a "fixed inlet" will only work optimal only at a certain point, you cannot compare it with an inlet that is designed to work at optimal performance at a range of speeds.
In a sense you are right, I don't see much of a performance between a fixed inlet types like DSI pitot etc etc. Not saying there isn't, just saying there isn't "much"; enough to be mentioned when comparing to a 3-5 oblique + normal shock inlets of various figthers.
Given that the subject was peak climb rate, you should have said SEP, if you wished to distinguish between the two. In the context at hand, the sentence was wrong.
Well, it was you that tried to include things like ascent angle to the discussion, so that overuse of technical terms would save you the day. Then I've asked the ascent angle at exact condition where MiG-29 achieved its 345m/s climb rate.
My claim was merely about climb rate all along; again you could have admitted your nonsense in ascent angle but you chose to humiliate yourself by saying 345m/s climb rate at M0,9 is impossible and I now no maths.. I don't need to say SEP, neither I feel the need to distinguish two. I will post this one again:
[ATTACH=CONFIG]248680[/ATTACH]
Vy, m/s vs M graph. This is easily the climb rate by Mach number graph by any definition you can find. Hence my comment, if you don't like it, mail MiG design bureu.
Haha, depends on what weights and configurations we look at.
Your choice of using 30000lbs is funny, as F-16 with full fuel load and 2 AAMs is 27316 lbs. Still I've noticed something curious: I've copied and pasted those 3 performance data from wikipedia I've thought they were exact same as quoted on eurofighter.com but somebody must have modified, upped and twisted these as well... Some guys really need a hobby...
This is the original claim:
Brakes off to 35,000ft / M1.5 <2.5 minutes
Brakes off to lift off <8 sec (Full Internals and Missiles)
At low level, 200Kts to Mach 1 =30 sec
Supercruise capability and Dry Power Acceleration from Sub to >Supersonic
I apologise for trusting the wikipedia sh!t without confirming it.
Also to quote myself:
An air-air payload of F-16 plus full fuel load makes roughly Drag index = 32 and 28000 lbs
F-16@ DI =0 28000 lbs -> 200 kts to M1.0 in 27,2 seconds.
F-16@ DI =50 28000 lbs -> 200 kts to M1.0 in 30,5 seconds.
Interpolating both will give us 29,3 seconds, FASTER than Eurofighters published 30 seconds.
So F-16 with its full fuel and full A-A payload is better accelerating than Typhoon.
Eurofighter takes less then 150 seconds. Overly simplifiying DI=25 acceleration from 200 kias to M0,9 takes 23,5 seconds. Climb to 35k feet takes roughly 1 minute, acceleration from M0,9 to M1,5 @30k takes ~66,5 seconds, totaling at 150 seconds. Though take off and reaching 200 kias will also take time, a more optimal climb/acceleration profile (for example climbing at M0,9 at first then diving for quick acceleration at ~15k feet than continuing to climb at M1.5) will shorten those times. While this is not conculsive as the example above, its sufficent to say the performance difference between types is not that much.
Skimming the EM graphs, best profile for F-16 should be to accelerate to M0,9 at deck, climb to ~20k, and as excess power is better at supersonic speeds at higher altitudes, accelerate to M1,3 at 20k first then make climb to 25k at M1,3 then climb & accelerate to M1,6 and 35k feet.
Conclusion is; Typhoon is slower accelerating than F-16, but perhaps a few seconds faster in climbs even if F-16 follows an optimal climb/acceleration profile.
Then your current comparison is with MiG-29, Even just at 25% fuel, DI=0 F-16 can barely achieve ~320m/s climb rate tops. Assuming the induced drag remains same, it would have around 254 m/s climb rate at 100% fuel. ("Interesting" I've found F-16's cited climb rate of 50k feet/min, so manufacturer must have given climb rate for full fuel load) MiG-29 makes 345m/s climb rate with nearly 57% fuel. With 100% fuel, it has 311m/s again assuming induced drag remains the same (for the record it remains the same for MiG-29).
At M1,6 30k point, F-16 blk50 has 124 m/s climb rate @25% fuel. At same conditions MiG-29 has 180m/s @57% fuel. When both are at full fuel, F-16 blk50 has 101 m/s and MiG-29 has 164 m/s climb rates respectively.
So I have, once again, proven F-16 with full fuel and 2 AAMs has ballpark similar time from 0 to 35000k feet M1,5 above. If we take the manufacturer data as our basis and not your beloved wiki. I am sure you will dig better numbers from somewhere around the web, but whatever.
When both F-16 and MiG-29 are at full fuel, starting from deck, MiG-29 has 22% climb rate / specific excess power advantage compared to F-16 blk50. At M1,6s 30k point it has 62% higher excess power.. Yet another example as to why variable inlets are not only slightly better, but they literally rock compared to fixed inlets. Typhoon is an OK match for F-16 in climbs and acceleration. I am willingly accept its a few seconds faster in climbs, but suggesting Typhoon for a comparison with in a climb/acceleration contest with a MiG-29A is a joke, I am sorry.
I won't calculate the brakes off to M1,6 @ 35000 feet time of MiG-29, even though climb rate graph is all I need for that. I think I've made my point clearly enough...
You really need me to prove something that is even present on RAM Air induction equipped sportsbikes?
I'm shaking my head at this stage. You really have a degree.
Hahahaha you are hopeless. Air is only considered compressible only at above M0,85 hence the name transonic. You are saying talking about compression due to ram at 100mph?? Why not mention "Ram air" of 1971 Mustangs? Idiot...
Curiosly, people accused you being the same bullsh**ing guy as Lukos, frankly I didn't bother to think of it but curiously, I've posted this exact climb acceleration to lukos after he posted this:
I could be super generous and account for pitot intake at Mach 1.97:
0.97/0.91 = 1.066 (Difference in efficiency at Mach 1.5)
0.92/1.066 = 0.86 (Adjusted to provide same intake efficiency at Mach 1.97 relative to Variable ramp)
0.86/0.73 = 1.18 (Difference between adjusted efficiency and actual)*
Note this is unfair because Typhoon only has a fixed ramp which will yield roughly the same difference as variable ramp at Mach 1.5 but less at Mach 2. So this calculation greatly favours F-16.
[(1.97*1.18)/1.5]^2 = 2.4
[32,500-(1-1/2.400]/30,000 = 0.632 Net TWR
Still almost 10% down despite best possible case. So no, F-16 can't out-accelerate a Typhoon, no way no how.
And my response to Lukos (you) 2 years ago:
As a mechanical engineer that had additional turbomachinery courses plus a certificate on advanced aerodynamics, I dont have the slightest clue on what you are talking about.
Utter BS#1. Cd0 is not related to modernity. The age old Concorde or MiG-25 is likely to have **FAR** less supersonic Cd0 than F-22 or F-35.
BS#2. Cd0 is defined by airfoil. For NACA 64A204 F-16 uses, it is 0,02 period. For the UNKNOWN airfoil Typhoon uses, its UNKNOWN, period.
Speaking of M1.5, what wavedrag are you talking about? Comparing a canard-delta and a conventional tailled aircraft, you don't even know what emprical analysis are for.
Reality is far from the FACTUALLY WRONG calculations you are making.
Your response:
Do you have a degree or a PhD in the field?
Well idiot is an idiot despite 2 years of elapsed time between two discussions. Lukos just go **** yourself. When you take a new alias, humiliate yourself less for your own sake..
By: haavarla
- 3rd October 2016 at 19:00Permalink- Edited 1st January 1970 at 01:00
Compare, Su-27S and Su-35S is an exellent proving point to what Andraxx is trying to hammer into your thick head Starfish/Lukos..? If you aren't the same, well you are both equally thickheaded.
To the best of my knowledge, they both has the same inlet functions with variable ramp. with the only difference being Su-35S inlet is 6% larger and Nose/radar radom is slightly bigger.
It is said that the ventral Strakes on Su-35S is slightly smaller, but i have never been able to compare them and verify this. There is some sources that says the humpback on Su-35S is slighty larger vs vanila Su-27, but again i have never been able to verify this.
In short, they are very much the same jet.
Anyway, In your world Starfish, that means the Su-35S has better top speed, cause well it obviously has much better T/W ratio.. well think again.
What the Su-35S does have is better acceleration in subsonic speed, and in Transonic region. But not on top speed.
Aerodynamics is a strange and complex field. But seing you trying to sound smart, but really just dumb it down is a mixed emotion of pleasure and pain.
By: Andraxxus
- 3rd October 2016 at 19:00Permalink- Edited 1st January 1970 at 01:00
Hey, I didn't see this one:
Andraxx, do you think the sharp LERX on Mig-35 gives it less drag up the Mach chart?
And how does it contribute the the wings performance.
If we disregard the larger wing areal, does it mean the airfoil on Mig-35 is very different vs Mig-29 9.12?
Well, I can't comment on any of those for certain. If I were to speculate;
I think MiG-35's lerx isn't much different regarding sharpness, its a matter of being new built vs repainted aircraft.
Wings enlarged and while LERX didn't really grew as much in size, it does have greater camber. So it should support the lift of main wings equally well, I don't think there would be a significant difference in both ways. but due to greater camber, new lerx design should be a little more draggy on level flight. Probably this was necessary to improve the volume other than aerodynamic-only needs.
MiG-29 9.12A uses TsAGI P-177 airfoil, but original MiG-29K used P-177M airfoil with greater lift. There maybe additional "slight" modifications, but I don't think a very different airfoil is used. MiG-29 is already good as it is, no reason waste months to create an all new aircraft for miniscule improvement.
Greatest -perhaps the only significant- disadvantage of MiG-35 over MiG-29 is weight. I would expect some 13-13.5 tons empty weight for MiG-35, no amount of composites can improve that. That being said, I don't think there would be as much performance difference between MiG-35 and MiG-29A as there is between F-16A to F-16C blk50.
Personally, I find MiG-35 is a safe path upgrade of MiG-29, keeping its pros as much as possible, and mitigating its cons. Most ambitious advancements were made in parts commonality to improve manufacturing and maintenence, not maneuverability perfromance.
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By: Starfish Prime
- 4th October 2016 at 12:09Permalink- Edited 1st January 1970 at 01:00
Well I won't show a ****, not only because I don't see any reason to prove my degree to you, but also because I use same nickname in all websites I visit, and the present state of the country I am living in makes me would prefer to be anonymous.
My bachelors degree diploma has a big color logo of the university in the background and tiny golden logos as the texture of it. In my graduation year less than 15 people were graduated. I have already said I am currently master student at the same university and my thesis is related to aerodynamics. There are less than 5 masters degree students in mechanical engineering department and currently only myself is writing an aerodynamic related thesis.
My IP is already enough to reveal my city and district. If I also reveal my school, I would be openly revealing myself, even if hide my name. I wouldn't want to wake up with police at my door just because I may have insulted a politican years ago or wrote an inconvinient post here & there, just to prove myself to you, thanks. I could have easily faked a degree here, but instead, I write my reasons. If my word is not good enough nothing ever will be.
Oh I got the picture pretty well. Other than your claim regarding "EF" none of these aircraft claim M2.0+ top speeds.
F-22 can be an exception because it simply has great thrust, but surely it won't be as fast as F-15 it replaces, PAK-FA is limited by materials but it does have a variable inlet ramps.
Do you think M2.35 limit of MiG-29 or Su-27 came for other reasons? ALL limits came from durability reasons. Aerodynamically, MiG-29 can sustain 10-11Gs indefinately. But its still a 9G fighter. Given a little cold air both MiG-29 and Su-27 will easily pass M2.35. But durability prevents even M2.35 speeds for F-15 Su-27 or MiG-29 to be used indefinately.
Ah kind of my point. You are right. F-15 was many times stated "M2.5 class" or "M2.5+"
Yet M2.5 is its top speed limit, and its top actual speed is M2,25 for PW-100, M2,45 for PW-220, and M2,3 for PW-229. So "M2,5 class" or "M2,5" doesn't mean a s***.
So if a RAF Typhoon races with an Austrian Typhoon latter will win?
Ah I agree on that 100%. Then why bother with top speeds? Again, in your analogy, you are saying "M2.5+ F-15A is faster than M2.35 Su-27S, so it must have less drag, greater excess power and greater maneuverability".
Fact is F-15 isn't faster than Su-27, but some basic analysis will say its still less draggy when supersonic. Greater excess power and maneuverability is unbelievably dependent on altitude, attempted G, and airspeed, but generally at higher altitudes Su-27 is better at subsonic and high supersonic, and F-15 is better high transonic and low-mid supersonic speeds.
Lessons learned. 1-Such top speed claims are likely to be wrong. 2-Top speed doesn't reveal which aircraft is draggy and which is not.
Well, no suprise you would be wrong again. 102% is Vmax graph. The large graph (obviously) is routine operations graph. With manual saying "Use of Vmax switch is strictly prohibited", I wouldn't say its comperable to normal operations of Su-27's AL-31F. I could post the longer version from the manual about what Vmax does and after its use, how aircraft spends days inside the hangar with engines outside the aircraft, half dismantled perhaps.
Only embarrassing thing is you fail to grasp the fact MiG-29's engine is not designed for supercruising. You claim yourself an engineer, I don't understand how mentally retarded one needs to be to keep making this claim.
If I were to make same analogy as you do, your Typhoon cannot even do M2.5 yet MiG-25 with its huge weight and puny T/W can go 25+% faster.
Well my very first post was a "fixed inlet" will only work optimal only at a certain point, you cannot compare it with an inlet that is designed to work at optimal performance at a range of speeds.
In a sense you are right, I don't see much of a performance between a fixed inlet types like DSI pitot etc etc. Not saying there isn't, just saying there isn't "much"; enough to be mentioned when comparing to a 3-5 oblique + normal shock inlets of various figthers.
Well, it was you that tried to include things like ascent angle to the discussion, so that overuse of technical terms would save you the day. Then I've asked the ascent angle at exact condition where MiG-29 achieved its 345m/s climb rate.
My claim was merely about climb rate all along; again you could have admitted your nonsense in ascent angle but you chose to humiliate yourself by saying 345m/s climb rate at M0,9 is impossible and I now no maths.. I don't need to say SEP, neither I feel the need to distinguish two. I will post this one again:
[ATTACH=CONFIG]248680[/ATTACH]
Vy, m/s vs M graph. This is easily the climb rate by Mach number graph by any definition you can find. Hence my comment, if you don't like it, mail MiG design bureu.
Your choice of using 30000lbs is funny, as F-16 with full fuel load and 2 AAMs is 27316 lbs. Still I've noticed something curious: I've copied and pasted those 3 performance data from wikipedia I've thought they were exact same as quoted on eurofighter.com but somebody must have modified, upped and twisted these as well... Some guys really need a hobby...
This is the original claim:
Brakes off to 35,000ft / M1.5 <2.5 minutes
Brakes off to lift off <8 sec (Full Internals and Missiles)
At low level, 200Kts to Mach 1 =30 sec
Supercruise capability and Dry Power Acceleration from Sub to >Supersonic
I apologise for trusting the wikipedia sh!t without confirming it.
Also to quote myself:
So F-16 with its full fuel and full A-A payload is better accelerating than Typhoon.
Skimming the EM graphs, best profile for F-16 should be to accelerate to M0,9 at deck, climb to ~20k, and as excess power is better at supersonic speeds at higher altitudes, accelerate to M1,3 at 20k first then make climb to 25k at M1,3 then climb & accelerate to M1,6 and 35k feet.
Conclusion is; Typhoon is slower accelerating than F-16, but perhaps a few seconds faster in climbs even if F-16 follows an optimal climb/acceleration profile.
Then your current comparison is with MiG-29, Even just at 25% fuel, DI=0 F-16 can barely achieve ~320m/s climb rate tops. Assuming the induced drag remains same, it would have around 254 m/s climb rate at 100% fuel. ("Interesting" I've found F-16's cited climb rate of 50k feet/min, so manufacturer must have given climb rate for full fuel load) MiG-29 makes 345m/s climb rate with nearly 57% fuel. With 100% fuel, it has 311m/s again assuming induced drag remains the same (for the record it remains the same for MiG-29).
At M1,6 30k point, F-16 blk50 has 124 m/s climb rate @25% fuel. At same conditions MiG-29 has 180m/s @57% fuel. When both are at full fuel, F-16 blk50 has 101 m/s and MiG-29 has 164 m/s climb rates respectively.
So I have, once again, proven F-16 with full fuel and 2 AAMs has ballpark similar time from 0 to 35000k feet M1,5 above. If we take the manufacturer data as our basis and not your beloved wiki. I am sure you will dig better numbers from somewhere around the web, but whatever.
When both F-16 and MiG-29 are at full fuel, starting from deck, MiG-29 has 22% climb rate / specific excess power advantage compared to F-16 blk50. At M1,6s 30k point it has 62% higher excess power.. Yet another example as to why variable inlets are not only slightly better, but they literally rock compared to fixed inlets. Typhoon is an OK match for F-16 in climbs and acceleration. I am willingly accept its a few seconds faster in climbs, but suggesting Typhoon for a comparison with in a climb/acceleration contest with a MiG-29A is a joke, I am sorry.
I won't calculate the brakes off to M1,6 @ 35000 feet time of MiG-29, even though climb rate graph is all I need for that. I think I've made my point clearly enough...
Hahahaha you are hopeless. Air is only considered compressible only at above M0,85 hence the name transonic. You are saying talking about compression due to ram at 100mph?? Why not mention "Ram air" of 1971 Mustangs? Idiot...
Curiosly, people accused you being the same bullsh**ing guy as Lukos, frankly I didn't bother to think of it but curiously, I've posted this exact climb acceleration to lukos after he posted this:
And my response to Lukos (you) 2 years ago:
Your response:
Well idiot is an idiot despite 2 years of elapsed time between two discussions. Lukos just go **** yourself. When you take a new alias, humiliate yourself less for your own sake..
Heh, I said you could black-out your name. Clearly you can't show proof, because you don't have a degree.
F-22 claims well over M2.0 and has lower TWR than a Typhoon.
Nope, limits are limits. Operational limits are there for durability. 9g limit? An F-15 pulled 12g during Desert Storm.
Your arbitrary M2.0 limit for fixed intakes is proven false by the fact an F-16 with pitot intake manages M2.05. Fairly sure the Su-11 and Su-15 intakes were fixed too.
Except it was a M2.5+ fighter.
In a war time scenario, operational limits are meaningless and the true limit of M2.35 applies.
Fact is the Su-27 can't do Mach 2.5, so F-15 is faster. Fact is Typhoon has higher SL speed, HL speed and supercruise.
In an actual war, higher limit applies.
Difference is MiG-25 is heavier and unlike you, I can prove I have a degree.
Sure you can. The variation in efficiency close to than optimal point is small and probably alleviated by having a simpler, less restrictive intake, just as pitot outperforms variable ramps subsonic. For fixed ramp that optimal is supersonic, not subsonic, so fixed ramp != pitot, i.e. you were wrong.
It is impossible, you can't be climbing at 345m/s while at M0.9. That is a SEP chart, showing SEP in m/s. Or simply V[(Fn-D)/mg]. Not actual rate of climb.
30,000lbs gives an equal fuel/payload fraction for both aircraft. There is no twisting of data. The figure of M1.6 at 36,000ft in >2.5k minutes is direct from BAE.
Brakes off to take off in less than 8 seconds and supersonic under 30 seconds.
Brakes off to 36,000 feet Mach 1.6 in under 2½ minutes.
The Eurofighter.com figure includes QRA fit (DTs and missiles). Even says so in your link.
Nice try. The Eurofighter goes from 0kts ('brakes off') to M1.0 in <30s. It takes 8s for T-O plus another few seconds to reach 200kts. So you can add 12s to those F-16 figures.
Can't see how you reach this conclusion, you have made the very obvious error of eliminating the time from brakes off to M0.3.
Typhoon is stated to have >25% better climb rate than F-16.
Erm, nobody is talking about compressibility of air, we are talking about an increase in static pressure, which will occur as air is slowed down from any speed. The Bernoulli principle applies to incompressible flow. Haha, degree my backside!
You should have paid more attention to lukos, he was clearly a lot smarter than you.
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By: Starfish Prime
- 4th October 2016 at 12:14Permalink- Edited 1st January 1970 at 01:00
Compare, Su-27S and Su-35S is an exellent proving point to what Andraxx is trying to hammer into your thick head Starfish/Lukos..? If you aren't the same, well you are both equally thickheaded.
To the best of my knowledge, they both has the same inlet functions with variable ramp. with the only difference being Su-35S inlet is 6% larger and Nose/radar radom is slightly bigger.
It is said that the ventral Strakes on Su-35S is slightly smaller, but i have never been able to compare them and verify this. There is some sources that says the humpback on Su-35S is slighty larger vs vanila Su-27, but again i have never been able to verify this.
In short, they are very much the same jet.
Anyway, In your world Starfish, that means the Su-35S has better top speed, cause well it obviously has much better T/W ratio.. well think again.
What the Su-35S does have is better acceleration in subsonic speed, and in Transonic region. But not on top speed.
Aerodynamics is a strange and complex field. But seing you trying to sound smart, but really just dumb it down is a mixed emotion of pleasure and pain.
Don't believe everything you read. If something quacks like a duck, it's probably a duck. There is 9% more drag at M2.35 relative to M2.25. Vanilla Su-27 has 9,000lbf (14%) less thrust. The Su-35 would need ~27% (1.094x1.164) more drag to be limited to M2.25.
By: haavarla
- 4th October 2016 at 12:40Permalink- Edited 1st January 1970 at 01:00
Don't believe everything you read. If something quacks like a duck, it's probably a duck. There is 9% more drag at M2.35 relative to M2.25. Vanilla Su-27 has 9,000lbf (14%) less thrust. The Su-35 would need ~27% (1.094x1.164) more drag to be limited to M2.25.
Soo.. your conclusion, Sukhoi/KnAAZ own product brosure is full of ****??
The Su-35S has 16% more thrust.
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By: Starfish Prime
- 4th October 2016 at 13:23Permalink- Edited 1st January 1970 at 01:00
Soo.. your conclusion, Sukhoi/KnAAZ own product brosure is full of ****??
The Su-35S has 16% more thrust.
16% more for Su-35, 14% less for Su-27. Both statements are accurate. Modern brochures just tend to be more conservative.
By: haavarla
- 4th October 2016 at 16:37Permalink- Edited 1st January 1970 at 01:00
16% more for Su-35, 14% less for Su-27. Both statements are accurate. Modern brochures just tend to be more conservative.
Lol. How convinient for you. That way the EF can fly faster that BAE says in their product brosure.
That is just a pathetical statement by you, which only exist in your la-la-world.
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By: Starfish Prime
- 4th October 2016 at 18:00Permalink- Edited 1st January 1970 at 01:00
Lol. How convinient for you. That way the EF can fly faster that BAE says in their product brosure.
That is just a pathetical statement by you, which only exist in your la-la-world.
The figures in the Eurofighter Tech Guide specifically states a full AAM fit, which is basically a QRA fit that includes 3x1000L DTs, 4xAMRAAM and 4xASRAAM.
M2.0 was only ever a recommended limit because of the airframe material. Both the production manager and the structural test manager mentioned this during my time at BAE. DA2 even managed M2+ with RB199s. EAP, also Mach 2, even with RB199s. But guess what, add >25% more thrust and nothing changes? Pffft. Formally stated by Austrian AF.
By: Peregrinefalcon
- 4th October 2016 at 19:04Permalink- Edited 1st January 1970 at 01:00
I have followed this debate over the phone (had to work on the terrain) and wasn't able to join, but that would make a little difference because Andraxxus is doing excellent job literally destroying you Lukos!
Just a few points.
Surely to achieve a climb rate (actual, not SEP) of 345m/s, it needs to be going supersonic, no? When Western sources quote climb rate, they mean actual climb rate, sustained at a given point, not a measure of SEP.
"Nonsteady-state (dynamic) performance test methods were used to determine the
performance of the test airplane. The test data were obtained for level-flight
accelerations and for constant-Mach-number climbs at maximum power and at a
constant heading. The speed and altitude information obtained was used to determine
the total energy of the airplane, which is the sum of the potential and kinetic energy
at a given point in the flight envelope. The rate of change of the total energy per unit
time for the airplane is a measure of the climb potential (specific excess power) of
the vehicle".
So, even by western standards, climb potential is expressed as specific excess power.
"Climb Potential
The standard-day climb potential (or specific excess power) of the test airplane as
determined from the level-flight acceleration data is presented in figures 9(a) to 9(e)
for altitudes of 10,000 feet (3048 meters) to 50,000 feet (15,240 meters) at 10,000-foot
(3048-meter) intervals, As expected, the variation of climb potential with increasing
Mach number and altitude is similar to the trends of the curves of excess thrust
presented in figure."
"CONCLUDING REMARKS
The climb-potential (specific excess power) data obtained from the flight tests were
compared with available predicted performance data for the "average" or "typical"
F-104G airplane, It was found that the predicted data did not represent the actual
performance of the test airplane to the degree of accuracy required to compute
meaningful flight trajectories. Therefore, the flight-test excess-thrust and fuel-flow
data obtained were used to define an accurate performance model for the test airplane
for a standard day at maximum afterburner power."
In essence you base your point on the premises that all you need to determine the planes performance is static T/W ratio and wing loading.
Andraxxus gave the example of Su-27 and F-15 (using official flight manual data) where we can see that such primitive way of analyzing planes performance proved to be false.
Even above presented document shows that the predicted data did not represent the actual performance of the test airplane to the degree of accuracy required to compute meaningful flight trajectories and that the flight-test excess-thrust and fuel-flow data obtained were used to define an accurate performance model for the test airplane for a standard day at maximum afterburner power.
And you have static T/W ratio and wing loading for EF2000 to make a point :rolleyes:
On the other hand Andraxxus presented all the necessary data on RD33 engine dynamic thrust output (thrust dependence on height and speed) and official Mig data on climb rate.
It is impossible, you can't be climbing at 345m/s while at M0.9. That is a SEP chart, showing SEP in m/s. Or simply V[(Fn-D)/mg]. Not actual rate of climb.
[ATTACH=CONFIG]248704[/ATTACH]
Well, here says it is posible. If you read the text below the chart, it says "climb rate dependence on mach number and height at full afterburner engine setting".
If you insist on disproving that, someone might consider you to be insane (engineer) person ;)
By: garryA
- 4th October 2016 at 19:33Permalink- Edited 1st January 1970 at 01:00
No, I
Climb rate is not a physical representation of climb, it means ability of the aircraft to gain energy at 1G flight equal to the amount it gains of potential energy climbing by that amount.
So when at M0,9 306m/s, MiG-29 would have climb rate of 345m/s, this means it could make a climb at 90 degrees, and still have 345-306 = 39m/s additional climb rate, which can be used for acceleration on a vertical climb. You can calculate the acceleration from dKE=dPE -> m*v*a = m*g*dH your dH is your climb rate, V is the airspeed in m/s, so MiG-29 will have 1,25 m/s2 acceleration on 90 degree vertical climb at M0,9.
Can someone explain this , iam lost
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Posts: 949
By: Starfish Prime
- 5th October 2016 at 10:03Permalink- Edited 1st January 1970 at 01:00
I have followed this debate over the phone (had to work on the terrain) and wasn't able to join, but that would make a little difference because Andraxxus is doing excellent job literally destroying you Lukos!
"Nonsteady-state (dynamic) performance test methods were used to determine the
performance of the test airplane. The test data were obtained for level-flight
accelerations and for constant-Mach-number climbs at maximum power and at a
constant heading. The speed and altitude information obtained was used to determine
the total energy of the airplane, which is the sum of the potential and kinetic energy
at a given point in the flight envelope. The rate of change of the total energy per unit
time for the airplane is a measure of the climb potential (specific excess power) of
the vehicle".
So, even by western standards, climb potential is expressed as specific excess power.
"Climb Potential
The standard-day climb potential (or specific excess power) of the test airplane as
determined from the level-flight acceleration data is presented in figures 9(a) to 9(e)
for altitudes of 10,000 feet (3048 meters) to 50,000 feet (15,240 meters) at 10,000-foot
(3048-meter) intervals, As expected, the variation of climb potential with increasing
Mach number and altitude is similar to the trends of the curves of excess thrust
presented in figure."
"CONCLUDING REMARKS
The climb-potential (specific excess power) data obtained from the flight tests were
compared with available predicted performance data for the "average" or "typical"
F-104G airplane, It was found that the predicted data did not represent the actual
performance of the test airplane to the degree of accuracy required to compute
meaningful flight trajectories. Therefore, the flight-test excess-thrust and fuel-flow
data obtained were used to define an accurate performance model for the test airplane
for a standard day at maximum afterburner power."
In essence you base your point on the premises that all you need to determine the planes performance is static T/W ratio and wing loading.
Andraxxus gave the example of Su-27 and F-15 (using official flight manual data) where we can see that such primitive way of analyzing planes performance proved to be false.
Even above presented document shows that the predicted data did not represent the actual performance of the test airplane to the degree of accuracy required to compute meaningful flight trajectories and that the flight-test excess-thrust and fuel-flow data obtained were used to define an accurate performance model for the test airplane for a standard day at maximum afterburner power.
And you have static T/W ratio and wing loading for EF2000 to make a point :rolleyes:
On the other hand Andraxxus presented all the necessary data on RD33 engine dynamic thrust output (thrust dependence on height and speed) and official Mig data on climb rate.
[ATTACH=CONFIG]248704[/ATTACH]
Well, here says it is posible. If you read the text below the chart, it says "climb rate dependence on mach number and height at full afterburner engine setting".
If you insist on disproving that, someone might consider you to be insane (engineer) person ;)
Cheers!
Nope, they're are both measuring specific excess power at given air speeds. This is often described as climb potential but it is not actual climb rate. I hope mathematics is a good enough source for you.
If V < 340m/s, Climb rate cannot be >340m/s because sin(alpha) cannot exceed 1.0.
If this is where the MiG-29's 'climb rate' comes from then it is extremely false. Both drag and thrust can and will change non-linearly between M0.9 and M1.2, so SEP at M0.9 at SL != Actual ascent rate capability at SL.
Oh and BTW, your link states that the predicted performance did not match the actual. So what's the bet that 'climb potential' does not match actual ascent rate? Let's put this another way, if I drop something like a brick from 10km altitude, will all the PE become KE?
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Posts: 949
By: Starfish Prime
- 5th October 2016 at 10:08Permalink- Edited 1st January 1970 at 01:00
But that is only their static thrust , may be their dynamic thrust at mach 2 doesnt change much
Super unlikely, here's why. RB199 were designed for the Tornado fighter bomber during the '70s, when low altitude interdiction was the order of the day. They are hence optimised for low altitude subsonic. EJ200s on the other hand are optimised for medium-high altitude transonic and supersonic. They also have a lower BPR (0.4 vs 1.1) and hence a higher jet velocity, giving superior thrust at high speeds as well as a higher specific thrust.
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Posts: 949
By: Starfish Prime
- 5th October 2016 at 10:15Permalink- Edited 1st January 1970 at 01:00
Can someone explain this , iam lost
Basically, there's something called SEP (Specific Excess Power), which is also given by the same equation as climb rate by coincidence:
V*([T-D]/W)
It is basically a measure of the amount of excess power an aircraft has at a given airspeed in level flight per unit weight. It is not an actual rate of climb because:
Now if, as in this case V is less than 340m/s (306m/s for M0.9), then actual climb rate can't be 345m/s because sin (alpha) has a maximum value of 1.0, which would equate to a direct vertical climb. It's a pseudo approximation of climb potential but since both drag and thrust vary extremely non-linearly between M0.9 and M1.2 (likely optimum climb speed), it is a very poor approximation in this case.
The V*([T-D]/W) is derived by substitution of ([T-D]/W) = sin (alpha) because resolving forces parallel to flight direction gives T = D + W.sin(alpha).
Andraxxus and Peregrinfalcon are trying to pull a fast one. To actually climb at 345m/s, assuming alpha is ~60deg, the aircraft would need to be going ~398m/s or M1.17. Now to climb at that rate, then in level flight at that speed (M1.17), it's there that the SEP would have to be 345m/s. And we see from the graph, that isn't the case, it's about 120m/s at 1km altitude.
Now the Typhoon claims >315m/s, which requires V of 364m/s at 60deg, so it has >315m/s SEP at 364m/s or M1.07, whereas the MiG has about 170m/s. I rest my case.
In summary, two equations must be satisfied to attain that actual climb rate (hdot):
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By: eagle - 2nd October 2016 at 16:39 Permalink - Edited 1st January 1970 at 01:00
Well it was fun for a while but there's a limit to everything. Maybe in due time I can be bothered to reply to one of your next aliases.
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By: Starfish Prime - 2nd October 2016 at 16:55 Permalink - Edited 1st January 1970 at 01:00
What?
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By: Andraxxus - 3rd October 2016 at 11:37 Permalink - Edited 1st January 1970 at 01:00
Inlet cone is also a fixed inlet if the cone itself doesn't move to match the shocks.
Go tell that to MiG, Sukhoi, Boeing etc engineers. Latest F-15E variants, Su-35 MiG-35 are still built with ramps, they must be wasting their time.
You are basing your assumptions on a "likely" which isn't shared by the manufacturer.
No I don't think so, just like I don't find M2.5 limit of F-15 "too rounded" to claim it is "likely" to be M2,67 or something...
AF statements do make mistakes, and sometimes they are too negligent to check&update their website. The very fact that German UK and Austrian airforces give different numbers for exact same aircraft should at least make you question a little bit.
On some regards Official military websites DO give erroneous information. A particular Sovremenny destroyer Russian Navy website claims as operational doesn't even have a engine inside it.
Ah but there are reasons for it. too much hp&torque = more taxes & insurance costs, less buyers. too little hp and torque = underpowered vehicle, less buyers. But I don't recall any car that has "underrated" top speed or acceleration. Because faster is always better, and no one will inflate their emissions, because higher emissions is always a bad thing (both for environment and for taxes).
Well, that is frankly irrelevant. its airframe + engine limit is M2,83. Given the cold enough air like -15 or so, I am 100.00% sure a Su-27 can do M2,5+ without any modifications, but its not safe at all, an sure as hell this is not its top speed.
MiG-25 has too much exess thrust at around M2,83 but that only helps it to overcome the additional drag comes from payloads, so it could still fly at M2,7 with 4x500kg bombs.. This doesn't make its top speed a tad faster than M2.83.
Yes. PW-100 engined like I've said. Without Vmax of course, meaning no 102% trim. Risking destruction of engines is not exacly an apples to apples comparison with Su-27.
[ATTACH=CONFIG]248674[/ATTACH]
Though you reposted a graph probably either me or poster Eagle first posted on this forum, I thank you that it perfectly proved my point that no F-15A/C/E can reach M2.5 on level flight at standard day, despite M2.5 is often quoted as its top speed. Kind of proving my point that M2.35, even if it may be true, may only be the top limit speed but not the actual top speed...
A book printed in 2002, giving info for an aircraft introduced into service in 2003. We are in 2016 and that book contradicts with everything else that doesn't quote it as source. Great one.
Speaking of DRY thrust, it obviously have far greater supersonic T-D. It doesn't show anything else about optimisation or anything you spit on this forum. For the 13049134th time you are comparing an two different engines, in a flight regime one engine simply isn't designed for.
But its way faster at high altitudes, so climb rates at upper half of the envelope must be better? Funny to see you claim superior performance based on top speed, then get back to real world to type some "excuses" when your "proof" can lead to much more interesting conclusions.
"Climbing" does not equate to "climb rate". I didn't say how fast it could climb, I've asked for your explaination about a given "climb rate". Don't try to twist this as well.
Ah I thought we were talking about climb rate. For climbing to an altitude/speed point, I've *PROVED* an F-16 (with not THAT spectacular climb or acceleration performance) can quite match (or exceed) both
"Brakes-off to supersonic acceleration: <30 s"
"Brakes-off to Mach 1.6 at 11,000 m (36,000 ft): <150 s"
Too lazy to quote myself, did the calculation in the past, a forum search would do it. Or better, don't take my word for it, sum up the values yourself; here's the relevant pages I am reposting:
[ATTACH=CONFIG]248669[/ATTACH][ATTACH=CONFIG]248670[/ATTACH][ATTACH=CONFIG]248671[/ATTACH]
You don't have to do a guess work for optimal climb&acceleration path. Just accelerate to M0,9 @ S/L, climb to 30k feet then accelerate to M1,6. This rather oversimplified flight path will still yield quite interesting results.
Well, I still don't see it as a ramp intake. In way-too-much laymans terms, ramp moves itself as such to make oblique shock "seal" the inlet. By doing so, when that shock expands, the "inlet side" of the shock has higher than atmospheric pressure but an exact M1.0 speed. If the oblique shock doesn't align with the inlet area air still slows down, but for pressure recovery its not exactly useful.
Ramp intake = F-14/15 Su-27 MiG-25/29/31 etc etc.
Splitter plate, aircraft's nose, wings, canopy rudders, even F-18's LERX all cause oblique shocks. Otherwise calling a splitter plate an inlet ramp is simply WRONG even if a Dr. Engineer from Chrysler Aerospace claims as such.
If splittler plate is considered a "fixed ramp", then F-16/18C, Rafale, B-1B etc all have fixed ramps.
I didn't argue with your point because it did not matter.
Su-27 has variable inlet ramps with M2.35 top speed. Su-34 really did have a fixed inlet ramp (that is ramps welded in a certain angle) and its top speed is M1,8.
Exact same thing applies to B-1A -> B-1B, Su-24A -> Su-24B and some tornado variants, even F-14D.
You were talking about stagnation pressure, when you kept calling it "total" pressure. It did not matter in any case, because "dynamic" part of stagnation pressure is necessarily fixed by the intake velocity demanded by the engine. If its M0,6 it has to be at M0,6. So the actual variable on that part is the static pressure.
I didn't bother going on with that discussion because P01 and P02 are arbitrary points. What is 01 and what is 02? If *I* were to name those in an inlet analysis, 0 would be atmospheric, 01 and 02 would represent pressures after shock#1 and shock#2. Its definately not so in your case, and its up to your source to properly mention WHAT those numbers represent.
Show me it can? Better yet, provide an dynamic Thrust data for ANY aircraft that has a fixed inlet, yet has impressive enough thrust to prove Typhoon *may* have good enough T/W at supersonic?
Your comment is as idiotic as claiming painting the aircraft gray demonstrates how fast the aircraft is.
IF being the appropirate word there. Again neither you or I have info about that. But mk1 eyeball observation.
Typhoon: idle = nozzles expanded. pilot increases thrust for take off:
First, nozzles close, then they start to expand, then afterburners lit. This early expension tells us (me at least) flow becomes supersonic after some point inside dry thrust.
MiG-29: idle = nozzles expanded just like Typhoon. Pilot increases thrust:
Nozzles close, remain closed as we see black smoke increase, then afterburner is lit and right at the same time nozzles start to expand. This tells us nozzles work in convergent on whole dry thrust regime and only con-di at wet thrust.
Now thrust is not only about velocity it has a pressure component as well, and skin friction and shocks from the body of the aircraft actually slow the air to quite subsonic esspecially near M1.0 airspeeds (that is why its called transonic), so MiG-29 can go a tad above M1.0 (M1.04 to be exact).
I don't know I didn't design RD-33. I would suspect however, not "just because" of nozzles. It has to provide sufficent velocity or pressure on DRY thrust at first to allow a nozzle converge enough so it can generate supersonic thrust. Without changing the design of engine itself, a simple nozzle modification won't give supercruise ability.
As for T-D, I've never claimed MiG-29's drag to be lower than Typhoon at supersonic regime. For all I know, MiG-29 is designed primarily for subsonic high manuevebility, and Typhoon is for supersonic. It would be very stupid to claim Typhoon would have higher drag at supersonic than MiG-29; about as stupid as claiming Typhoon would have less drag than Su-27/MiG-29/F-16 etc at subsonic, esspecially at lower altitudes. I still think MiG-29 would have greater T/W due to greater WET thrust, but much even greater drag would *probably* hinder it supersonic. Same goes for Su-27 which you were originally comparing.
You were making up horse**** based on "superior T/W" magic. I've shown MiG-29 has way greater T/W on some parts of envelope. At the very least, I've PROVED uninstalled thrust can NEVER be a basis of thrust comparison between aircraft. Nothing more nothing less. You could have accepted this like a man, but you immediately twisted your argument to Climb rate.
That didn't make sense, climb rate is still best before wavedrag and around M0,85-M0,9 is subsonic, part of envelope MiG-29 will have similar or less drag and a higher thrust than Typhoon. Then, again instead of accepting this, you twisted your argument to top speed and supercruise.
In that area you could have sticked to manufacturer data, but you couldn't do it because it didn't fit your propoganda. Instead, you took your one top speed from Austrian airforce which could easily be an error on web designer's part because NO ONE ELSE claims as such, and second (sea level) top speed you quote a source, who quotes 2002 book of "llustrated Directory of Fighters by Mike Spick". Quoting an 2002 book is esspecially funny for an aircraft entered into service in 2003..
Su-35 has greater thrust than Su-27 yet manufacturerer says it is slower. That is good enough for me. Typhoon manufacturer says Typhoon is slower than MiG-29, and that is also good enough for me. I don't care at all if that isn't good enough for you, if you have to nitpick something else that says faster, just to prove yours is bigger in a pissing contest, that is your own inferiority complexity to deal with.
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By: Starfish Prime - 3rd October 2016 at 13:37 Permalink - Edited 1st January 1970 at 01:00
Yes but it still produces an oblique shock before the normal shock, which is far superior to a normal shock. This is aerodynamics 101, there's no way you have a degree, show me evidence.
F-22 isn't, F-35 isn't, EF isn't, Rafale isn't, Gripen isn't, J-20 isn't, PAK-FA probably isn't. Get the picture.
Actually it is, BAE states 1,522mph, EADS stated M2+. M2.0 only came up due to lifetime durability consideration of the air frame material. It was never a T-D limit.
F-15 was stated at M2.5+. F-22 as 'Mach 2 class'.
Operational norms for different air forces differ.
Not at all, all the vehicles I'm thinking of are top brackets for road tax and insurance.
Top speed is always quoted clean and in the remit we're discussing (climb rate), it's the T-D trend that's important, not the actual structural integrity.
Well the other trim figures are for short of 100%, so I would argue the 102% trim is the most valid. And it's not necessary it would risk the engines. Adding a little more fuel to the reheat does not risk the crucial core components at all.
Once again, the flight manuals are always 100%. Data is very often estimated. Eagles have gone over M2.5 in practice.
Like what? The performance data would have been well known by that time.
Surely the MiG-29's variable geometry intakes should help in supercruise, yet the Typhoon still manages 50% more. How embarrassing.
Idiotic analogy. The MiG-29 and Typhoon weigh the same. The MiG-25 weighs far more and has a much lower TWR. High altitude climb rate does not equal low altitude peak climb rate. Up there the air is thin and being able to fly faster produces more lift.
You're the one twisting it Mr. 'Fixed ramps are the same as pitot'. Given that the subject was peak climb rate, you should have said SEP, if you wished to distinguish between the two. In the context at hand, the sentence was wrong.
Haha, depends on what weights and configurations we look at.
Okay I'll bite, your SL acceleration table starts at 200kts. So you can add at least 12s to all those times. The HL acceleration table is also at the wrong altitude. But starting at basic aircraft weight of 20,168lb, 30,000lb GW (DI=0), gives up the closest match on fuel fraction (32.X% for both a/c). Extrapolation, that puts the 200kts to M0.91 time at 24.5s, so add 12s for 0-200kts and you have 36.5s, this also still excludes the altitude change during lift off and landing gear raise. Now begins the climb. 70s for 35,000ft. and 80s for climb to 40,000ft, so ~72s for climb to 36,000ft. That puts us at 108.5s. Extrapolate between 28,000lb and 32,000lb and we get 75s for M0.91-M1.62. Giving at total of 183.5s, or just under 3 minutes, so Typhoon is >33.5s faster.
In fact, even if the Tyhoon starts at rest and the F-16C starts at 200kts, the Typhoon still gets to M1.6 at 36,000ft >20s quicker. Nice example. Ooooh, and BTW, you do know the top speed of the F-16C is M2.05. Still doubt that M2.35 and that whole >M2.0 thing?
A ramp will create an oblique shock. This will not slow down air to subsonic, it slows it down to a lower supersonic Mach number, following which a normal shock slows it to subsonic. The deceleration to subsonic is always via a normal shock regardless of the intake, however if you do it from a very high Mach number, you lose a lot of total pressure and it's inefficient. If you apply 1 or more oblique shocks first it's more efficient. Now a variable ramp will allow you to optimise your oblique shock, and two will allow you to optimise 2 oblique shocks etc. there's ultimately no limit except weight and complexity. However a fixed ramp will still produce an oblique shock but it will only be the optimal oblique shock at one speed. However, it will still be better than a pitot's 1 normal shock at any supersonic speed. By setting the fixed ramp for M1.3-M1.4, you can produce as near as damnit, the same performance at variable geometry up to M1.6 and several % better than pitot.
The Typhoon is not calling the splitter plate a fixed ramp.
Well it kind of did matter because you used a graph I posted showing total pressure ratio across two inlets to suggest that the MiG's intake was superior because it increased pressure. Total pressure never increases in an inlet. P01 is the start of the intake, P02 is at the face of the engine. It is the part of the intake after the normal shock that slows air down to whatever the engine is designed for.
You really need me to prove something that is even present on RAM Air induction equipped sportsbikes?
https://en.wikipedia.org/wiki/Kawasaki_Ninja_ZX-6R
*This is at 100mph.
I'm shaking my head at this stage. You really have a degree.
Not really, it makes perfect sense in demonstrating the relationship between drag and thrust at low to intermediate supersonic speeds.
Well I'm not going to look, but if that's the case it's a very crap design and I struggle to believe the designers would be so stupid as to only have the con-di operational on reheat.
Well you were claiming the MiG-29 had a higher peak sustained climb rate, which is achieved at low supersonic speeds. So if you agree the Typhoon has lower drag supersonic and higher thrust, plus the same weight, it stands to reason that the Typhoon can beat it on climb rate.
You haven't shown jack, because we don't have thrust vs velocity graphs for the EJ200, but we do know they're optmised for M0.9-M1.6. Because it obviously applies to climb rate. What is climb rate about if not TWR and drag?
Surely to achieve a climb rate (actual, not SEP) of 345m/s, it needs to be going supersonic, no? When Western sources quote climb rate, they mean actual climb rate, sustained at a given point, not a measure of SEP.
Well using your own data I've shown a Typhoon to reach 36,000ft and M1.6 much quicker than an F-16C, which can do M2.05. Enough said.
My money would be on the Su-35.
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By: FBW - 3rd October 2016 at 14:57 Permalink - Edited 1st January 1970 at 01:00
No, they haven't and flight manuals are not "estimated" at all. They are based on actual test flights on specific dates, which are noted on the pages. You are using manufacturer data, information off particular service pages which is often estimated and frequently incorrect. No F-15 could "in practice" achieve close to mach 2.5 without using the v-max augmentation which could damage the engines. Second, no armed F-15 could approach mach 2.5, making the stated top speed theoretical at best.
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By: Andraxxus - 3rd October 2016 at 18:35 Permalink - Edited 1st January 1970 at 01:00
Well I won't show a ****, not only because I don't see any reason to prove my degree to you, but also because I use same nickname in all websites I visit, and the present state of the country I am living in makes me would prefer to be anonymous.
My bachelors degree diploma has a big color logo of the university in the background and tiny golden logos as the texture of it. In my graduation year less than 15 people were graduated. I have already said I am currently master student at the same university and my thesis is related to aerodynamics. There are less than 5 masters degree students in mechanical engineering department and currently only myself is writing an aerodynamic related thesis.
My IP is already enough to reveal my city and district. If I also reveal my school, I would be openly revealing myself, even if hide my name. I wouldn't want to wake up with police at my door just because I may have insulted a politican years ago or wrote an inconvinient post here & there, just to prove myself to you, thanks. I could have easily faked a degree here, but instead, I write my reasons. If my word is not good enough nothing ever will be.
Oh I got the picture pretty well. Other than your claim regarding "EF" none of these aircraft claim M2.0+ top speeds.
F-22 can be an exception because it simply has great thrust, but surely it won't be as fast as F-15 it replaces, PAK-FA is limited by materials but it does have a variable inlet ramps.
Do you think M2.35 limit of MiG-29 or Su-27 came for other reasons? ALL limits came from durability reasons. Aerodynamically, MiG-29 can sustain 10-11Gs indefinately. But its still a 9G fighter. Given a little cold air both MiG-29 and Su-27 will easily pass M2.35. But durability prevents even M2.35 speeds for F-15 Su-27 or MiG-29 to be used indefinately.
Ah kind of my point. You are right. F-15 was many times stated "M2.5 class" or "M2.5+"
Yet M2.5 is its top speed limit, and its top actual speed is M2,25 for PW-100, M2,45 for PW-220, and M2,3 for PW-229. So "M2,5 class" or "M2,5" doesn't mean a s***.
So if a RAF Typhoon races with an Austrian Typhoon latter will win?
Ah I agree on that 100%. Then why bother with top speeds? Again, in your analogy, you are saying "M2.5+ F-15A is faster than M2.35 Su-27S, so it must have less drag, greater excess power and greater maneuverability".
Fact is F-15 isn't faster than Su-27, but some basic analysis will say its still less draggy when supersonic. Greater excess power and maneuverability is unbelievably dependent on altitude, attempted G, and airspeed, but generally at higher altitudes Su-27 is better at subsonic and high supersonic, and F-15 is better high transonic and low-mid supersonic speeds.
Lessons learned. 1-Such top speed claims are likely to be wrong. 2-Top speed doesn't reveal which aircraft is draggy and which is not.
Well, no suprise you would be wrong again. 102% is Vmax graph. The large graph (obviously) is routine operations graph. With manual saying "Use of Vmax switch is strictly prohibited", I wouldn't say its comperable to normal operations of Su-27's AL-31F. I could post the longer version from the manual about what Vmax does and after its use, how aircraft spends days inside the hangar with engines outside the aircraft, half dismantled perhaps.
Only embarrassing thing is you fail to grasp the fact MiG-29's engine is not designed for supercruising. You claim yourself an engineer, I don't understand how mentally retarded one needs to be to keep making this claim.
If I were to make same analogy as you do, your Typhoon cannot even do M2.5 yet MiG-25 with its huge weight and puny T/W can go 25+% faster.
Well my very first post was a "fixed inlet" will only work optimal only at a certain point, you cannot compare it with an inlet that is designed to work at optimal performance at a range of speeds.
In a sense you are right, I don't see much of a performance between a fixed inlet types like DSI pitot etc etc. Not saying there isn't, just saying there isn't "much"; enough to be mentioned when comparing to a 3-5 oblique + normal shock inlets of various figthers.
Well, it was you that tried to include things like ascent angle to the discussion, so that overuse of technical terms would save you the day. Then I've asked the ascent angle at exact condition where MiG-29 achieved its 345m/s climb rate.
My claim was merely about climb rate all along; again you could have admitted your nonsense in ascent angle but you chose to humiliate yourself by saying 345m/s climb rate at M0,9 is impossible and I now no maths.. I don't need to say SEP, neither I feel the need to distinguish two. I will post this one again:
[ATTACH=CONFIG]248680[/ATTACH]
Vy, m/s vs M graph. This is easily the climb rate by Mach number graph by any definition you can find. Hence my comment, if you don't like it, mail MiG design bureu.
Your choice of using 30000lbs is funny, as F-16 with full fuel load and 2 AAMs is 27316 lbs. Still I've noticed something curious: I've copied and pasted those 3 performance data from wikipedia I've thought they were exact same as quoted on eurofighter.com but somebody must have modified, upped and twisted these as well... Some guys really need a hobby...
This is the original claim:
Brakes off to 35,000ft / M1.5 <2.5 minutes
Brakes off to lift off <8 sec (Full Internals and Missiles)
At low level, 200Kts to Mach 1 =30 sec
Supercruise capability and Dry Power Acceleration from Sub to >Supersonic
This is the source: http://www.eurofighter.com/downloads/TecGuide.pdf 10th page general performance characteristics (as they are provided by official manufacturer not lukos or wiki)
I apologise for trusting the wikipedia sh!t without confirming it.
Also to quote myself:
So F-16 with its full fuel and full A-A payload is better accelerating than Typhoon.
Skimming the EM graphs, best profile for F-16 should be to accelerate to M0,9 at deck, climb to ~20k, and as excess power is better at supersonic speeds at higher altitudes, accelerate to M1,3 at 20k first then make climb to 25k at M1,3 then climb & accelerate to M1,6 and 35k feet.
Conclusion is; Typhoon is slower accelerating than F-16, but perhaps a few seconds faster in climbs even if F-16 follows an optimal climb/acceleration profile.
Then your current comparison is with MiG-29, Even just at 25% fuel, DI=0 F-16 can barely achieve ~320m/s climb rate tops. Assuming the induced drag remains same, it would have around 254 m/s climb rate at 100% fuel. ("Interesting" I've found F-16's cited climb rate of 50k feet/min, so manufacturer must have given climb rate for full fuel load) MiG-29 makes 345m/s climb rate with nearly 57% fuel. With 100% fuel, it has 311m/s again assuming induced drag remains the same (for the record it remains the same for MiG-29).
At M1,6 30k point, F-16 blk50 has 124 m/s climb rate @25% fuel. At same conditions MiG-29 has 180m/s @57% fuel. When both are at full fuel, F-16 blk50 has 101 m/s and MiG-29 has 164 m/s climb rates respectively.
So I have, once again, proven F-16 with full fuel and 2 AAMs has ballpark similar time from 0 to 35000k feet M1,5 above. If we take the manufacturer data as our basis and not your beloved wiki. I am sure you will dig better numbers from somewhere around the web, but whatever.
When both F-16 and MiG-29 are at full fuel, starting from deck, MiG-29 has 22% climb rate / specific excess power advantage compared to F-16 blk50. At M1,6s 30k point it has 62% higher excess power.. Yet another example as to why variable inlets are not only slightly better, but they literally rock compared to fixed inlets. Typhoon is an OK match for F-16 in climbs and acceleration. I am willingly accept its a few seconds faster in climbs, but suggesting Typhoon for a comparison with in a climb/acceleration contest with a MiG-29A is a joke, I am sorry.
I won't calculate the brakes off to M1,6 @ 35000 feet time of MiG-29, even though climb rate graph is all I need for that. I think I've made my point clearly enough...
Hahahaha you are hopeless. Air is only considered compressible only at above M0,85 hence the name transonic. You are saying talking about compression due to ram at 100mph?? Why not mention "Ram air" of 1971 Mustangs? Idiot...
Curiosly, people accused you being the same bullsh**ing guy as Lukos, frankly I didn't bother to think of it but curiously, I've posted this exact climb acceleration to lukos after he posted this:
And my response to Lukos (you) 2 years ago:
Your response:
Well idiot is an idiot despite 2 years of elapsed time between two discussions. Lukos just go **** yourself. When you take a new alias, humiliate yourself less for your own sake..
Posts: 6,441
By: haavarla - 3rd October 2016 at 19:00 Permalink - Edited 1st January 1970 at 01:00
Compare, Su-27S and Su-35S is an exellent proving point to what Andraxx is trying to hammer into your thick head Starfish/Lukos..? If you aren't the same, well you are both equally thickheaded.
Su-35S Dry 8.800kgf Wet 14.500kgf
Su-27S Dry 7.600kgf Wet 12.500kgf
To the best of my knowledge, they both has the same inlet functions with variable ramp. with the only difference being Su-35S inlet is 6% larger and Nose/radar radom is slightly bigger.
It is said that the ventral Strakes on Su-35S is slightly smaller, but i have never been able to compare them and verify this. There is some sources that says the humpback on Su-35S is slighty larger vs vanila Su-27, but again i have never been able to verify this.
In short, they are very much the same jet.
Anyway, In your world Starfish, that means the Su-35S has better top speed, cause well it obviously has much better T/W ratio.. well think again.
What the Su-35S does have is better acceleration in subsonic speed, and in Transonic region. But not on top speed.
Aerodynamics is a strange and complex field. But seing you trying to sound smart, but really just dumb it down is a mixed emotion of pleasure and pain.
Posts: 932
By: Andraxxus - 3rd October 2016 at 19:00 Permalink - Edited 1st January 1970 at 01:00
Hey, I didn't see this one:
Well, I can't comment on any of those for certain. If I were to speculate;
I think MiG-35's lerx isn't much different regarding sharpness, its a matter of being new built vs repainted aircraft.
http://cdn.airplane-pictures.net/images/uploaded-images/2010/9/27/103771.jpg
http://data.primeportal.net/hangar/luc_colin/mig-29ub_huaf/images/mig-29ub_huaf_02_of_16.jpg
Wings enlarged and while LERX didn't really grew as much in size, it does have greater camber. So it should support the lift of main wings equally well, I don't think there would be a significant difference in both ways. but due to greater camber, new lerx design should be a little more draggy on level flight. Probably this was necessary to improve the volume other than aerodynamic-only needs.
MiG-29 9.12A uses TsAGI P-177 airfoil, but original MiG-29K used P-177M airfoil with greater lift. There maybe additional "slight" modifications, but I don't think a very different airfoil is used. MiG-29 is already good as it is, no reason waste months to create an all new aircraft for miniscule improvement.
Greatest -perhaps the only significant- disadvantage of MiG-35 over MiG-29 is weight. I would expect some 13-13.5 tons empty weight for MiG-35, no amount of composites can improve that. That being said, I don't think there would be as much performance difference between MiG-35 and MiG-29A as there is between F-16A to F-16C blk50.
Personally, I find MiG-35 is a safe path upgrade of MiG-29, keeping its pros as much as possible, and mitigating its cons. Most ambitious advancements were made in parts commonality to improve manufacturing and maintenence, not maneuverability perfromance.
Posts: 949
By: Starfish Prime - 4th October 2016 at 12:09 Permalink - Edited 1st January 1970 at 01:00
Heh, I said you could black-out your name. Clearly you can't show proof, because you don't have a degree.
F-22 claims well over M2.0 and has lower TWR than a Typhoon.
Nope, limits are limits. Operational limits are there for durability. 9g limit? An F-15 pulled 12g during Desert Storm.
Your arbitrary M2.0 limit for fixed intakes is proven false by the fact an F-16 with pitot intake manages M2.05. Fairly sure the Su-11 and Su-15 intakes were fixed too.
Except it was a M2.5+ fighter.
In a war time scenario, operational limits are meaningless and the true limit of M2.35 applies.
Fact is the Su-27 can't do Mach 2.5, so F-15 is faster. Fact is Typhoon has higher SL speed, HL speed and supercruise.
In an actual war, higher limit applies.
Difference is MiG-25 is heavier and unlike you, I can prove I have a degree.
Sure you can. The variation in efficiency close to than optimal point is small and probably alleviated by having a simpler, less restrictive intake, just as pitot outperforms variable ramps subsonic. For fixed ramp that optimal is supersonic, not subsonic, so fixed ramp != pitot, i.e. you were wrong.
It is impossible, you can't be climbing at 345m/s while at M0.9. That is a SEP chart, showing SEP in m/s. Or simply V[(Fn-D)/mg]. Not actual rate of climb.
30,000lbs gives an equal fuel/payload fraction for both aircraft. There is no twisting of data. The figure of M1.6 at 36,000ft in >2.5k minutes is direct from BAE.
http://www.baesystems.com/en-uk/product/typhoon2
The Eurofighter.com figure includes QRA fit (DTs and missiles). Even says so in your link.
Nice try. The Eurofighter goes from 0kts ('brakes off') to M1.0 in <30s. It takes 8s for T-O plus another few seconds to reach 200kts. So you can add 12s to those F-16 figures.
Can't see how you reach this conclusion, you have made the very obvious error of eliminating the time from brakes off to M0.3.
Typhoon is stated to have >25% better climb rate than F-16.
Erm, nobody is talking about compressibility of air, we are talking about an increase in static pressure, which will occur as air is slowed down from any speed. The Bernoulli principle applies to incompressible flow. Haha, degree my backside!
https://en.wikipedia.org/wiki/Bernoulli%27s_principle
You should have paid more attention to lukos, he was clearly a lot smarter than you.
Posts: 949
By: Starfish Prime - 4th October 2016 at 12:14 Permalink - Edited 1st January 1970 at 01:00
Don't believe everything you read. If something quacks like a duck, it's probably a duck. There is 9% more drag at M2.35 relative to M2.25. Vanilla Su-27 has 9,000lbf (14%) less thrust. The Su-35 would need ~27% (1.094x1.164) more drag to be limited to M2.25.
Posts: 6,441
By: haavarla - 4th October 2016 at 12:40 Permalink - Edited 1st January 1970 at 01:00
Soo.. your conclusion, Sukhoi/KnAAZ own product brosure is full of ****??
The Su-35S has 16% more thrust.
Posts: 949
By: Starfish Prime - 4th October 2016 at 13:23 Permalink - Edited 1st January 1970 at 01:00
16% more for Su-35, 14% less for Su-27. Both statements are accurate. Modern brochures just tend to be more conservative.
Posts: 6,441
By: haavarla - 4th October 2016 at 16:37 Permalink - Edited 1st January 1970 at 01:00
Lol. How convinient for you. That way the EF can fly faster that BAE says in their product brosure.
That is just a pathetical statement by you, which only exist in your la-la-world.
Posts: 949
By: Starfish Prime - 4th October 2016 at 18:00 Permalink - Edited 1st January 1970 at 01:00
The figures in the Eurofighter Tech Guide specifically states a full AAM fit, which is basically a QRA fit that includes 3x1000L DTs, 4xAMRAAM and 4xASRAAM.
M2.0 was only ever a recommended limit because of the airframe material. Both the production manager and the structural test manager mentioned this during my time at BAE. DA2 even managed M2+ with RB199s. EAP, also Mach 2, even with RB199s. But guess what, add >25% more thrust and nothing changes? Pffft. Formally stated by Austrian AF.
http://www.bundesheer.at/waffen/waf_eurofighter.shtml
Posts: 427
By: Peregrinefalcon - 4th October 2016 at 19:04 Permalink - Edited 1st January 1970 at 01:00
I have followed this debate over the phone (had to work on the terrain) and wasn't able to join, but that would make a little difference because Andraxxus is doing excellent job literally destroying you Lukos!
Just a few points.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710017526.pdf
I hope NASA is enough western source for you?
"Nonsteady-state (dynamic) performance test methods were used to determine the
performance of the test airplane. The test data were obtained for level-flight
accelerations and for constant-Mach-number climbs at maximum power and at a
constant heading. The speed and altitude information obtained was used to determine
the total energy of the airplane, which is the sum of the potential and kinetic energy
at a given point in the flight envelope. The rate of change of the total energy per unit
time for the airplane is a measure of the climb potential (specific excess power) of
the vehicle".
So, even by western standards, climb potential is expressed as specific excess power.
"Climb Potential
The standard-day climb potential (or specific excess power) of the test airplane as
determined from the level-flight acceleration data is presented in figures 9(a) to 9(e)
for altitudes of 10,000 feet (3048 meters) to 50,000 feet (15,240 meters) at 10,000-foot
(3048-meter) intervals, As expected, the variation of climb potential with increasing
Mach number and altitude is similar to the trends of the curves of excess thrust
presented in figure."
"CONCLUDING REMARKS
The climb-potential (specific excess power) data obtained from the flight tests were
compared with available predicted performance data for the "average" or "typical"
F-104G airplane, It was found that the predicted data did not represent the actual
performance of the test airplane to the degree of accuracy required to compute
meaningful flight trajectories. Therefore, the flight-test excess-thrust and fuel-flow
data obtained were used to define an accurate performance model for the test airplane
for a standard day at maximum afterburner power."
In essence you base your point on the premises that all you need to determine the planes performance is static T/W ratio and wing loading.
Andraxxus gave the example of Su-27 and F-15 (using official flight manual data) where we can see that such primitive way of analyzing planes performance proved to be false.
Even above presented document shows that the predicted data did not represent the actual performance of the test airplane to the degree of accuracy required to compute meaningful flight trajectories and that the flight-test excess-thrust and fuel-flow data obtained were used to define an accurate performance model for the test airplane for a standard day at maximum afterburner power.
And you have static T/W ratio and wing loading for EF2000 to make a point :rolleyes:
On the other hand Andraxxus presented all the necessary data on RD33 engine dynamic thrust output (thrust dependence on height and speed) and official Mig data on climb rate.
[ATTACH=CONFIG]248704[/ATTACH]
Well, here says it is posible. If you read the text below the chart, it says "climb rate dependence on mach number and height at full afterburner engine setting".
If you insist on disproving that, someone might consider you to be insane (engineer) person ;)
Cheers!
Posts: 1,081
By: garryA - 4th October 2016 at 19:08 Permalink - Edited 1st January 1970 at 01:00
But that is only their static thrust , may be their dynamic thrust at mach 2 doesnt change much
Posts: 1,081
By: garryA - 4th October 2016 at 19:33 Permalink - Edited 1st January 1970 at 01:00
Can someone explain this , iam lost
Posts: 949
By: Starfish Prime - 5th October 2016 at 10:03 Permalink - Edited 1st January 1970 at 01:00
Nope, they're are both measuring specific excess power at given air speeds. This is often described as climb potential but it is not actual climb rate. I hope mathematics is a good enough source for you.
Climb rate = V.sin (alpha)
http://www.dept.aoe.vt.edu/~lutze/AOE3104/climb.pdf
http://www.srmuniv.ac.in/sites/default/files/downloads/class12-2012.pdf
If V < 340m/s, Climb rate cannot be >340m/s because sin(alpha) cannot exceed 1.0.
If this is where the MiG-29's 'climb rate' comes from then it is extremely false. Both drag and thrust can and will change non-linearly between M0.9 and M1.2, so SEP at M0.9 at SL != Actual ascent rate capability at SL.
Oh and BTW, your link states that the predicted performance did not match the actual. So what's the bet that 'climb potential' does not match actual ascent rate? Let's put this another way, if I drop something like a brick from 10km altitude, will all the PE become KE?
Posts: 949
By: Starfish Prime - 5th October 2016 at 10:08 Permalink - Edited 1st January 1970 at 01:00
Super unlikely, here's why. RB199 were designed for the Tornado fighter bomber during the '70s, when low altitude interdiction was the order of the day. They are hence optimised for low altitude subsonic. EJ200s on the other hand are optimised for medium-high altitude transonic and supersonic. They also have a lower BPR (0.4 vs 1.1) and hence a higher jet velocity, giving superior thrust at high speeds as well as a higher specific thrust.
Posts: 949
By: Starfish Prime - 5th October 2016 at 10:15 Permalink - Edited 1st January 1970 at 01:00
Basically, there's something called SEP (Specific Excess Power), which is also given by the same equation as climb rate by coincidence:
V*([T-D]/W)
It is basically a measure of the amount of excess power an aircraft has at a given airspeed in level flight per unit weight. It is not an actual rate of climb because:
Actual Rate of Climb = V * sin (alpha)
http://www.dept.aoe.vt.edu/~lutze/AOE3104/climb.pdf
Now if, as in this case V is less than 340m/s (306m/s for M0.9), then actual climb rate can't be 345m/s because sin (alpha) has a maximum value of 1.0, which would equate to a direct vertical climb. It's a pseudo approximation of climb potential but since both drag and thrust vary extremely non-linearly between M0.9 and M1.2 (likely optimum climb speed), it is a very poor approximation in this case.
The V*([T-D]/W) is derived by substitution of ([T-D]/W) = sin (alpha) because resolving forces parallel to flight direction gives T = D + W.sin(alpha).
Andraxxus and Peregrinfalcon are trying to pull a fast one. To actually climb at 345m/s, assuming alpha is ~60deg, the aircraft would need to be going ~398m/s or M1.17. Now to climb at that rate, then in level flight at that speed (M1.17), it's there that the SEP would have to be 345m/s. And we see from the graph, that isn't the case, it's about 120m/s at 1km altitude.
Now the Typhoon claims >315m/s, which requires V of 364m/s at 60deg, so it has >315m/s SEP at 364m/s or M1.07, whereas the MiG has about 170m/s. I rest my case.
In summary, two equations must be satisfied to attain that actual climb rate (hdot):
hdot = V*sin(alpha)
AND
V*([T-D]/W) = hdot
OR put another way:
[hdot/sin(alpha)]*([T-D]/W) = hdot = [hdot/sin(alpha)]*[1/sin(alpha)]
since ([T-D]/W) = sin(alpha)
So we actually see from Andraxxus' graph that whilst the MiG-29 has SEP of 345m/s at M0.9@SL, it can't actually maintain a climb at that rate.