By: Peregrinefalcon
- 5th October 2016 at 21:52Permalink- Edited 1st January 1970 at 01:00
Andraxxus and Peregrinfalcon are trying to pull a fast one.
Sure we are, but just to make some things clear...
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):
If I'm understanding you correctly, let's say for example that the plane X travels at 187 m/s at sea level. The actual max climb rate at ~60° climb angle for the X plane should be ~162,6 m/s according to your calculation method?
Am I right?
And if I'm wrong, can you calculate for me the max climb rate for the X plane at 60 and 90° climb angle?
By: Andraxxus
- 6th October 2016 at 02:25Permalink- Edited 1st January 1970 at 01:00
Can someone explain this , iam lost
Peregrinefalcon's NASA quote explains it better;
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".
The with zero excess power flies in Thrust = drag condition. If thrust is higher than drag (or lower), there will be a force (kg*m/s^2) on a moving object (m/s), there will be a rate of increase in energy in Joule/s, or kg*m^2/s^2 to write it in a more open form.
Thermodynamics law: Total energy of the system = Kinetic energy of system + Potential energy of system + internal energy of the system.
This law can apply to everything, and if we consider whole aircraft as this thermodynamic system, internal energy won't change (ie, aircraft won't heat up etc). So equation becomes E = KE+PE.
As a performance parameter, we are looking on rate of kinetic energy change or potential energy change, so we take the differential of both sides;
rate of energy change(dE) = dKE (rate of KE change) + dPE (rate of PE change).
Power = mass*Velocity*dVelocity + mass*G*dHeight.
dVelocity = rate of change in velocity, which means acceleration
dHeight = rate of change in height, which means climb rate.
divide both sides by mass and there is;
Specific Power = velocity*acceleration + G*climb rate.
Now as I've written above specific power has no meaning for the pilot; Some 1000 watt/kg is not a quantifiable measurement for him. So instead of giving such performance parameter, we divide both sides with G so we have
Climb-rate/potential (as performance parameter) = velocity*acceleration/G + climb rate (as in aircrafts actual change in height).
Now if you are flying at 300 m/s, and you have 200 m/s climb rate as written in the manual, this means you can climb at 200m/s without losing speed. You can surely go 90deg vertical and climb at 300m/s for an instant, but accordingly to this -scalar- energy equation you would be trading KE (slowing down) for this rate of increase in PE. Likewise, you can climb at 100m/s and accelerate at the same time (both KE and PE increase). Or you can stick at 0m/s climb rate (dPE = 0) and climb rate will mathematically give the level flight acceleration of the aircraft. On descent rate of PE change is also added to the rate of KE change.
Even if you are flying at 309 m/s, an aircraft can surely have 345m/s climb rate. A SAM recently launched and flying 20-30 m/s can even have 500+ m/s climb rate. This climb rate is a mere representation of energy change of aircraft, which pilot can use in any combination of KE and PE change.
If climb rate is equal to aircraft's speed, this means aircraft can climb at 90 degree angle and won't speed up or slow down. If its higher, than this excess climb-potential will result in KE change, which means acceleration on vertical climb.
Despite it says "climb rate" graph its solely related with energy and should be read with caution: if a MiG-29 wants to make a quick climb from 11 km altitude, actual climb rate won't be highest around 180m/s @M1,7. It will be highest at M2,3 @ 678 m/s when MiG-29 makes an exact 90 degree vertical climb (assuming no direction change delays). But since MiG-29 has only 60m/s climb rate at that speed, it will see a quick deceleration equivalent to (60-678) m/s climb rate; 60-678 = v*a/g = -8,94 m/s^2 deceleration. Assuming constant deceleration, it will slow down to below M2,0 just within 10 seconds, but will have 633 m/s average climb rate during that time, to ascend it to 17km altitude.
For aerodynamics 101 this does not matter, as people are teached without this background, examplified by something with puny climb rates like B-737 or something, so certain know-it-all people can easily calculate angle from simple trigonometry. Its perfectly ok, but gets unamusing when they draw conclusions and making assumptions about all aircraft should climb at 60 degrees so climb rate will give an imaginary speed and draw even more conclusions from that.
Climb rate/potential is also variable with dynamic thrust, L/D and how much G aircraft pulls (which is also independent of aircraft weight), and its shown as lines for Energy-maneuverability diagram F-16 manual for example. In a sense, that diagram doesn't only show ITR and STR, it also shows the vertical play and acceleration capability of the F-16 as well. As energy is a scalar quantity (instead of vectoral), one an use this graph to say F-16 at Mach A pulling B amount of Gs can climb/descent C amount of meters and accelerate/decelerate by D amount.
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By: Starfish Prime
- 6th October 2016 at 08:43Permalink- Edited 1st January 1970 at 01:00
Sure we are, but just to make some things clear...
If I'm understanding you correctly, let's say for example that the plane X travels at 187 m/s at sea level. The actual max climb rate at ~60° climb angle for the X plane should be ~162,6 m/s according to your calculation method?
Am I right?
And if I'm wrong, can you calculate for me the max climb rate for the X plane at 60 and 90° climb angle?
Yes, unless the plane changes airspeed. 60deg is an approximation, it will vary depending on aircraft. I actually get 161.95m/s at 60deg and obviously 187m/s at 90deg.
Not specifically PE. The maximum actual sustained ascent rate at any speed is:
hdot = V*sin(alpha)
The maximum rate of climb is attained when this equation is at its highest and when:
V*([T-D]/W) is equal to the same value.
If V is not high enough, such that Vsin(alpha) != hdot
Then it does not stand as a legitimate climb rate, it is simply specific excess power and a measure of how much combined KE+PE an aircraft can gain from a given airspeed at peak thrust.
The first link shows how the optimum airspeed and angle is derived for a given aircraft.
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By: Starfish Prime
- 6th October 2016 at 09:08Permalink- Edited 1st January 1970 at 01:00
Peregrinefalcon's NASA quote explains it better;
The with zero excess power flies in Thrust = drag condition. If thrust is higher than drag (or lower), there will be a force (kg*m/s^2) on a moving object (m/s), there will be a rate of increase in energy in Joule/s, or kg*m^2/s^2 to write it in a more open form.
Thermodynamics law: Total energy of the system = Kinetic energy of system + Potential energy of system + internal energy of the system.
This law can apply to everything, and if we consider whole aircraft as this thermodynamic system, internal energy won't change (ie, aircraft won't heat up etc). So equation becomes E = KE+PE.
As a performance parameter, we are looking on rate of kinetic energy change or potential energy change, so we take the differential of both sides;
rate of energy change(dE) = dKE (rate of KE change) + dPE (rate of PE change).
Power = mass*Velocity*dVelocity + mass*G*dHeight.
dVelocity = rate of change in velocity, which means acceleration
dHeight = rate of change in height, which means climb rate.
divide both sides by mass and there is;
Specific Power = velocity*acceleration + G*climb rate.
Now as I've written above specific power has no meaning for the pilot; Some 1000 watt/kg is not a quantifiable measurement for him. So instead of giving such performance parameter, we divide both sides with G so we have
Climb-rate/potential (as performance parameter) = velocity*acceleration/G + climb rate (as in aircrafts actual change in height).
Now if you are flying at 300 m/s, and you have 200 m/s climb rate as written in the manual, this means you can climb at 200m/s without losing speed. You can surely go 90deg vertical and climb at 300m/s for an instant, but accordingly to this -scalar- energy equation you would be trading KE (slowing down) for this rate of increase in PE. Likewise, you can climb at 100m/s and accelerate at the same time (both KE and PE increase). Or you can stick at 0m/s climb rate (dPE = 0) and climb rate will mathematically give the level flight acceleration of the aircraft. On descent rate of PE change is also added to the rate of KE change.
Even if you are flying at 309 m/s, an aircraft can surely have 345m/s climb rate. A SAM recently launched and flying 20-30 m/s can even have 500+ m/s climb rate. This climb rate is a mere representation of energy change of aircraft, which pilot can use in any combination of KE and PE change.
If climb rate is equal to aircraft's speed, this means aircraft can climb at 90 degree angle and won't speed up or slow down. If its higher, than this excess climb-potential will result in KE change, which means acceleration on vertical climb.
Despite it says "climb rate" graph its solely related with energy and should be read with caution: if a MiG-29 wants to make a quick climb from 11 km altitude, actual climb rate won't be highest around 180m/s @M1,7. It will be highest at M2,3 @ 678 m/s when MiG-29 makes an exact 90 degree vertical climb (assuming no direction change delays). But since MiG-29 has only 60m/s climb rate at that speed, it will see a quick deceleration equivalent to (60-678) m/s climb rate; 60-678 = v*a/g = -8,94 m/s^2 deceleration. Assuming constant deceleration, it will slow down to below M2,0 just within 10 seconds, but will have 633 m/s average climb rate during that time, to ascend it to 17km altitude.
For aerodynamics 101 this does not matter, as people are teached without this background, examplified by something with puny climb rates like B-737 or something, so certain know-it-all people can easily calculate angle from simple trigonometry. Its perfectly ok, but gets unamusing when they draw conclusions and making assumptions about all aircraft should climb at 60 degrees so climb rate will give an imaginary speed and draw even more conclusions from that.
Climb rate/potential is also variable with dynamic thrust, L/D and how much G aircraft pulls (which is also independent of aircraft weight), and its shown as lines for Energy-maneuverability diagram F-16 manual for example. In a sense, that diagram doesn't only show ITR and STR, it also shows the vertical play and acceleration capability of the F-16 as well. As energy is a scalar quantity (instead of vectoral), one an use this graph to say F-16 at Mach A pulling B amount of Gs can climb/descent C amount of meters and accelerate/decelerate by D amount.
Nope, up to the bit in bold you were doing so well.
You are trying to conflate SEP and Climb Rate.
You had it here:
rate of energy change(dE) = dKE (rate of KE change) + dPE (rate of PE change).
By: Peregrinefalcon
- 6th October 2016 at 16:10Permalink- Edited 1st January 1970 at 01:00
Yes, unless the plane changes airspeed. 60deg is an approximation, it will vary depending on aircraft. I actually get 161.95m/s at 60deg and obviously 187m/s at 90deg.
Ok, that is all I need to know because the numbers for the X plane in my example are not used randomly, there is reason to it.
Since other explanations and charts by Andraxxus and NASA are not good enough for you I have this:
Here is the real world example where we can see that the (record breaking) F-15 at 420 mph on the deck (~187 m/s), has enough SEP to break the speed of sound (~340m/s) at 90° climb angle.
You can also see that at 450 mph (~200 m/s) and 55° climb angle the plane is accelerating through the speed of sound!
This is all in the line with explanations Andraxxus gave in the above post and examples I provided. On the other hand your calculations are so wrong it is beyond comprehension. You actually concluded that EF2000 has almost two times better climb rate than Mig-29:
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.
The only thing you should rest is this debate :rolleyes:
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By: Starfish Prime
- 7th October 2016 at 10:04Permalink- Edited 1st January 1970 at 01:00
Ok, that is all I need to know because the numbers for the X plane in my example are not used randomly, there is reason to it.
Since other explanations and charts by Andraxxus and NASA are not good enough for you I have this:
Here is the real world example where we can see that the (record breaking) F-15 at 420 mph on the deck (~187 m/s), has enough SEP to break the speed of sound (~340m/s) at 90° climb angle.
You can also see that at 450 mph (~200 m/s) and 55° climb angle the plane is accelerating through the speed of sound!
This is all in the line with explanations Andraxxus gave in the above post and examples I provided. On the other hand your calculations are so wrong it is beyond comprehension. You actually concluded that EF2000 has almost two times better climb rate than Mig-29:
The only thing you should rest is this debate :rolleyes:
You're still conflating SEP and rate of climb.
You cannot climb at X m/s unless Vsin(alpha) = X, this is a basic fact.
The video says the aircraft is at 450mph, pulls up into a 55deg climb and 25s later it is accelerating through the speed of sound (3:30).
So we see that SEP was converted into both d(KE/dt) and d(PE/dt). It did not reach maximum climb rate at 450mph, it accelerated and gained speed first.
At M0.9 (306m/s) the MiG-29 has a SEP of 345m/s, this cannot all be converted to climb rate at this speed, it must first gain speed, after which it will reach a point of greater velocity, where the remaining SEP is converted to climb rate.
You're arguing a point you don't understand with zero comprehension of physics. Basically, you're trolling.
By: Peregrinefalcon
- 7th October 2016 at 20:22Permalink- Edited 1st January 1970 at 01:00
...
Now, I intentionally asked you what climb rate would plane X have at 187 m/s on the deck for 60 and 90° climb angle and you answered (as I thought you would) 162 and 187 m/s.
First of all, answering that question without knowing a single thing about planes technical characteristics (since we are talking about plane X) is retarded by itself.
Second, the real world example is undoubtedly showing that numbers you provided have no base in reality.
The video shows that F-15 at 187 m/s on the deck has potential (climb potential or specific excess power - see NASA paper) to climb at much higher rate than 187 m/s at 90° climb angle. The plane has enough specific excess power to accelerate through the speed of sound in the vertical climb.
Now, if we had Boing 747 performing the same thing at 187 m/s, situation would be much different ;)
The video says the aircraft is at 450mph, pulls up into a 55deg climb and 25s later it is accelerating through the speed of sound (3:30).
So we see that SEP was converted into both d(KE/dt) and d(PE/dt).
First of all, he is not accelerating through the speed of sound 25 seconds after pulling into the climb, he is reaching that speed 25 seconds after the brake release.
It did not reach maximum climb rate at 450mph, it accelerated and gained speed first.
Really, let me think...the plane didn't reach its max climb rate while flying horizontally at 450 mph...it had to actually go in to the climb, accelerate in the climb and only then it reached its max climb rate!
Wow, I think you are genius :rolleyes:
On the serious note, this only shows that the plane has potential (climb potential) to accelerate in the climb (55 and 90° climb angle) at that particular speed.
And what is the climb potential?
"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".
At M0.9 (306m/s) the MiG-29 has a SEP of 345m/s, this cannot all be converted to climb rate at this speed, it must first gain speed, after which it will reach a point of greater velocity, where the remaining SEP is converted to climb rate.
You're arguing a point you don't understand with zero comprehension of physics. Basically, you're trolling.
It is the same thing as with F-15 in the video I posted. At that speed (306m/s), Mig-29 has energy potential (climb potential) of additional 39m/s (positve SEP), which can be used for acceleration on a vertical climb. Record breaking F-15 demonstrates that perfectly (only the numbers are different).
Now, if we assume that EF2000 has its best climb rate of 315 m/s at 0,9M, (same speed as Mig-29), that meens that it has energy potential (climb potential) of additional 9 m/s (positve SEP), which can be used for acceleration on a vertical climb.
But somehow, you with your perfect understanding of the subject concluded that EF2000 has almost TWO TIMES higher climb rate than Mig-29.
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By: Starfish Prime
- 8th October 2016 at 09:20Permalink- Edited 1st January 1970 at 01:00
Now, I intentionally asked you what climb rate would plane X have at 187 m/s on the deck for 60 and 90° climb angle and you answered (as I thought you would) 162 and 187 m/s.
First of all, answering that question without knowing a single thing about planes technical characteristics (since we are talking about plane X) is retarded by itself.
Second, the real world example is undoubtedly showing that numbers you provided have no base in reality.
The video shows that F-15 at 187 m/s on the deck has potential (climb potential or specific excess power - see NASA paper) to climb at much higher rate than 187 m/s at 90° climb angle. The plane has enough specific excess power to accelerate through the speed of sound in the vertical climb.
Now, if we had Boing 747 performing the same thing at 187 m/s, situation would be much different ;)
First of all, he is not accelerating through the speed of sound 25 seconds after pulling into the climb, he is reaching that speed 25 seconds after the brake release.
Really, let me think...the plane didn't reach its max climb rate while flying horizontally at 450 mph...it had to actually go in to the climb, accelerate in the climb and only then it reached its max climb rate!
Wow, I think you are genius :rolleyes:
On the serious note, this only shows that the plane has potential (climb potential) to accelerate in the climb (55 and 90° climb angle) at that particular speed.
And what is the climb potential?
"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".
It is the same thing as with F-15 in the video I posted. At that speed (306m/s), Mig-29 has energy potential (climb potential) of additional 39m/s (positve SEP), which can be used for acceleration on a vertical climb. Record breaking F-15 demonstrates that perfectly (only the numbers are different).
Now, if we assume that EF2000 has its best climb rate of 315 m/s at 0,9M, (same speed as Mig-29), that meens that it has energy potential (climb potential) of additional 9 m/s (positve SEP), which can be used for acceleration on a vertical climb.
But somehow, you with your perfect understanding of the subject concluded that EF2000 has almost TWO TIMES higher climb rate than Mig-29.
I stated that the angle of climb varies but is usually ~60deg for a fighter class aircraft. I have several times posted a link detailing how V optimum and alpha optimum are calculated, so please don't try pretend you're clever.
You asked for climb rate, not SEP, you are again conflating the two. SEP != climb rate. The answer I provided was for the speed mentioned and that speed only. SEP is NOT Climb Rate!
It says, "after release", that could mean brakes off or take off. Either way, it's well known that the Streak Eagle was a non-standard aircraft. Stripped of nearly all avionics, even paint and had uprated thrust. TWR was over 2:1 on empty weight.
Yes, but sadly you are not a genius, which is why I've been trying to explain this very point to both you and Andraxxus for several pages. SEP at a given speed does not equal climb rate at that speed or maximum climb rate. It is a measure of the ability to gain speed and altitude. Unless Vsin(alpha optimum) equals climb rate then the SEP at that V does not equal climb rate.
Nope, you're still not getting it. The SEP at 450mph was not all converted to climb rate, some was converted to velocity (KE). As per the following:
As speed increased, SEP decreased, but the V was then sufficient to achieve the optimum climb rate and the remaining SEP could be converted to climb rate.
No because as the speed of the MiG increases, drag increases and the SEP, given by:
V*([T-D]/W)
Therefore reduces.
Seriously how can V*([T-D]/W) be the same at M0.9 as say M1.2?
The graph clearly shows the SEP at SL is zero at M1.2, so how can it climb at say a 55deg angle at the latter speed? And even if it did, it would only achieve 334m/s climb rate by Vsin(alpha)*.
(*I apologise for using alpha, it's confusing, as it's usually used to refer to AoA but here I use it as the angle of ascent.)
I never said it had twice the climb rate, I said it had nearly twice the SEP at a given speed. There is a difference, as I've been trying to point out.
Come back when you really understand this post and the subject matter, because it's clear to all that you don't.
By: Andraxxus
- 8th October 2016 at 11:52Permalink- Edited 1st January 1970 at 01:00
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.
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.
You have once again my point of twisting data and being an dishonorable LIAR!!.
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1- Eurofighter.com says "with a full Air-to-Air Missile fit." It says f**ng missiles. No 1000l fuel tanks. It actually doesn't even say full internal fuel, I assume as such for the sake of argument and comparison; If an F-16 beats or matches Typhoon performance with 100% fuel, that it will certainly beat it in lesser fuels. Since F-16 does just that, I don't bother an argument of how much fuel Typhoon may be carrying, it doesn't matter if its 100%.
2- Eurofighter.com says 200kts to M1,0, NOT from "brakes off". And NO "<30" seconds it says "in 30 seconds", not "less than" or "under". I don't need to add a milisecond because F-16 manual gives EXACTLY that; with full fuel and A-A payload, from 200kts to M1,0 in 29,3 seconds.
3- BAE systems website does NOT even say "with full Air to Air payload" like Eurofighter official website do, let alone your 3x drop tanks BS. You are take a claim from Eurofighter website, inflate it with your BS (this time by adding 3x1000l tanks), then you try to pass it as something taken from BAE's website.... Most (actually the ONLY) logical explaination for this contradicting data between two official sources is BAE system give data for Typhoon with much lighter payloads.
1-brakes off to 35k feet M1,5 under 2,5 minutes with full A-A missile fit.
2-brakes off to 36k feet M1,6 under 2,5 minutes with unknown payload... Maybe for a clean aircraft with 50% or even less fuel.
1-200kts to M1,0 in 30 seconds with full A-A fit.
2-brakes off to M1,0 under 30 seconds with unknown payload.
For the 1st claims, F-16 beats Typhoon in acceleration and *MAYBE* just a few seconds slower in climb. I am not so certain its slower as I didn't do an optimal climb profile.
I don't have a comparison basis for the 2nd claims, and I simply ignore them, and I have no idea why you keep bringing these up (like you did two years ago with your "Lukos" alias). Payload and fuel is VERY important to make a valid comparison.
No fuel and payload criteria? Then it doesn't tell anything about the performance of the aircraft.. Even an F-4 can climb from 0 to 35000 feet in 42 seconds given its light enough. I won't do the whole math, but this sufficently light F-4 could probably take-off and make necessary accelerations in the remaining 208 seconds, maybe miss it by a 5-10 seconds at best.
A simple "take off, accelerate to M0,9 climb to 35k feet, accelerate to M1,5" profile takes 150 seconds on F-16 excluding the 8-12 second take off part. For the 300th time, F-16 can achieve better climb time above 20k feet if its supersonic (instead of keep climbing at M0,9). It also accelerates to M0,9 to M1,5 full 13 seconds faster at this altitude (53 seconds @20k feet vs 66 seconds@30k feet), so it can shave quite a few seconds from that overly simplistic 150 second time.
I can make time calculations for this relatively more optimal climb profile for F-16, and Climb and Acceleration time is perfectly calculable from climb-rate graph of MiG-29, but I don't think anyone else is interested, and I won't waste my 50 minutes for you. My point is crystal clear; Typhoon is only an even match for a Block 50 F-16 at best, and MiG-29A has 22% to 62% better 1G excess power compared to same F-16.
I don't have any stomach left to discuss with you. You win OK? I was wrong and this Lukos/Starfish guy was right all along..
Starfish/Lukos says:
-Su-27S has the highest (subsonic) sustained turn rates of all 4th gen fighters at mid-high altitude, but Typhoon has it better.
-Su-27S has the highest (subsonic) sustained turns of all 4th gen aircraft when fuel weight is equalised for same range, but Typhoon is better.
-F-16 blk30 has the highest (subsonic) sustained turn rate among all a 4th gen fighter with 50% fuel, but Typhoon is better.
-MiG-29 has the greatest (subsonic) climb rate value among all 4th gen fighters, and greatest off-the-deck climb performance, but Typhoon is better.
-MiG-25 and MiG-31 are the fastest combat aircraft ever entered service, but Typhoon is faster than those when carrying EFTs (M2,0 vs M1,7 and M1,5 for MiG-25 and MiG-31 respectively)
-F-15E with PW-229 is the fastest fighter aircraft with heavy payloads, yet Typhoon with 8 missiles and 3 EFTs is faster than F-15E with 8 missiles and no EFTs but only CFTs (M2,0 vs M1,9).
All that subsonic performance, despite the fact Typhoon is designed for high-altitude supersonic regime.
All that impressive high mach top speeds with EFTs, despite puny 90kN engines and a fixed inlet.
These should say how Typhoon is the bestest product mankind has ever made. Happy now?
Speaking of climbs, a nice video of MiG-29's off the deck climb with centerline fuel tank (this is the first time I've mentioned this fuel tank, since we are idiot enough to think every hanging EFT is fully loaded with fuel during airshows) https://youtu.be/VCWjByenDsM?t=40s
Not that I would claim for a second Typhoon is any worse than that of course. Even without no evidence, Typhoon is better because it is the bestest aircraft.
By: garryA
- 8th October 2016 at 12:16Permalink- Edited 1st January 1970 at 01:00
^
Sarcasm aside isn't SR-71 faster than Mig-25/31?
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By: Starfish Prime
- 8th October 2016 at 15:37Permalink- Edited 1st January 1970 at 01:00
You have once again my point of twisting data and being an dishonorable LIAR!!.
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1- Eurofighter.com says "with a full Air-to-Air Missile fit." It says f**ng missiles. No 1000l fuel tanks. It actually doesn't even say full internal fuel, I assume as such for the sake of argument and comparison; If an F-16 beats or matches Typhoon performance with 100% fuel, that it will certainly beat it in lesser fuels. Since F-16 does just that, I don't bother an argument of how much fuel Typhoon may be carrying, it doesn't matter if its 100%.
2- Eurofighter.com says 200kts to M1,0, NOT from "brakes off". And NO "<30" seconds it says "in 30 seconds", not "less than" or "under". I don't need to add a milisecond because F-16 manual gives EXACTLY that; with full fuel and A-A payload, from 200kts to M1,0 in 29,3 seconds.
3- BAE systems website does NOT even say "with full Air to Air payload" like Eurofighter official website do, let alone your 3x drop tanks BS. You are take a claim from Eurofighter website, inflate it with your BS (this time by adding 3x1000l tanks), then you try to pass it as something taken from BAE's website.... Most (actually the ONLY) logical explaination for this contradicting data between two official sources is BAE system give data for Typhoon with much lighter payloads.
1-brakes off to 35k feet M1,5 under 2,5 minutes with full A-A missile fit.
2-brakes off to 36k feet M1,6 under 2,5 minutes with unknown payload... Maybe for a clean aircraft with 50% or even less fuel.
1-200kts to M1,0 in 30 seconds with full A-A fit.
2-brakes off to M1,0 under 30 seconds with unknown payload.
For the 1st claims, F-16 beats Typhoon in acceleration and *MAYBE* just a few seconds slower in climb. I am not so certain its slower as I didn't do an optimal climb profile.
I don't have a comparison basis for the 2nd claims, and I simply ignore them, and I have no idea why you keep bringing these up (like you did two years ago with your "Lukos" alias). Payload and fuel is VERY important to make a valid comparison.
No fuel and payload criteria? Then it doesn't tell anything about the performance of the aircraft.. Even an F-4 can climb from 0 to 35000 feet in 42 seconds given its light enough. I won't do the whole math, but this sufficently light F-4 could probably take-off and make necessary accelerations in the remaining 208 seconds, maybe miss it by a 5-10 seconds at best.
A simple "take off, accelerate to M0,9 climb to 35k feet, accelerate to M1,5" profile takes 150 seconds on F-16 excluding the 8-12 second take off part. For the 300th time, F-16 can achieve better climb time above 20k feet if its supersonic (instead of keep climbing at M0,9). It also accelerates to M0,9 to M1,5 full 13 seconds faster at this altitude (53 seconds @20k feet vs 66 seconds@30k feet), so it can shave quite a few seconds from that overly simplistic 150 second time.
I can make time calculations for this relatively more optimal climb profile for F-16, and Climb and Acceleration time is perfectly calculable from climb-rate graph of MiG-29, but I don't think anyone else is interested, and I won't waste my 50 minutes for you. My point is crystal clear; Typhoon is only an even match for a Block 50 F-16 at best, and MiG-29A has 22% to 62% better 1G excess power compared to same F-16.
I don't have any stomach left to discuss with you. You win OK? I was wrong and this Lukos/Starfish guy was right all along..
Starfish/Lukos says:
-Su-27S has the highest (subsonic) sustained turn rates of all 4th gen fighters at mid-high altitude, but Typhoon has it better.
-Su-27S has the highest (subsonic) sustained turns of all 4th gen aircraft when fuel weight is equalised for same range, but Typhoon is better.
-F-16 blk30 has the highest (subsonic) sustained turn rate among all a 4th gen fighter with 50% fuel, but Typhoon is better.
-MiG-29 has the greatest (subsonic) climb rate value among all 4th gen fighters, and greatest off-the-deck climb performance, but Typhoon is better.
-MiG-25 and MiG-31 are the fastest combat aircraft ever entered service, but Typhoon is faster than those when carrying EFTs (M2,0 vs M1,7 and M1,5 for MiG-25 and MiG-31 respectively)
-F-15E with PW-229 is the fastest fighter aircraft with heavy payloads, yet Typhoon with 8 missiles and 3 EFTs is faster than F-15E with 8 missiles and no EFTs but only CFTs (M2,0 vs M1,9).
All that subsonic performance, despite the fact Typhoon is designed for high-altitude supersonic regime.
All that impressive high mach top speeds with EFTs, despite puny 90kN engines and a fixed inlet.
These should say how Typhoon is the bestest product mankind has ever made. Happy now?
Speaking of climbs, a nice video of MiG-29's off the deck climb with centerline fuel tank (this is the first time I've mentioned this fuel tank, since we are idiot enough to think every hanging EFT is fully loaded with fuel during airshows) https://youtu.be/VCWjByenDsM?t=40s
Not that I would claim for a second Typhoon is any worse than that of course. Even without no evidence, Typhoon is better because it is the bestest aircraft.
1. Full AAM fit is basically the standard QRA load, which is 4xAMRAAM + 4xASRAAM + 3x1000L DTs. It's evidently a lot slower than the clean figures BAE provides, so DI is certainly not zero.
2. Irrelevant, the BAE figures are for the clean aircraft, the GmbH figures are for a loaded aircraft. You can argue about the load all day but clearly it is loaded and the DI is not zero.
3. That's because the BAE figures are clean, just as the original F-16 figures were. That's what DI=0 means remember.
The 'unknown payload' is clean. DI=0. The GmbH load is DI !=0 and likely implies the standard QRA fit given the performance delta with the clean figures.
Yeah, because for the first claim you are comparing DI=0 with DI != 0. When you compare DI=0 with DI=0, the Typhoon wins by over 30s. How seriously disingenuous of you.
Sure you do, you have the DI=0 figures. And even at 20,000lbs GW (i.e. less than empty, empty weight was actually over 20,168lb, so they must have removed stuff https://info.publicintelligence.net/HAF-F16-Supplement.pdf), the F-16 can't get from brakes off to M1.0 in <30s. 19s from M0.3-1.0 + ~12s for M0.0-0.3 gives 31s. Get the picture yet?
At 24,000lb GW, which is about half fuel only, it's at 34s M0.0-0.98 and still can't beat the Typhoon to M1.6 and 36,000ft. So like I said, "no way, no how!" You just can't accept that you're wrong.
The load is now irrelevant because I just proved that even at sub-empty weight the F-16 can't beat the Typhoon to M1.0. And as far as that goes, the Eurofighter tech guide doesn't specify fuel load either, it's just assumed that it starts with full internal fuel on your part, whereas it's likely the standard QRA fit, since that would be the most applicable to customers.
Even if we play, the no DTs dice, it's still 8 AAMs, so we'll use the 30,000lb ground weight with DI=50 for the F-16 (which is still a lower fuel fraction and even 2 AIM-9Ls on pylons and adaptors has a DI of 22 and there will be 6 missiles on such, with 2 on the wing tips). I'm also letting you off on weight a little too. And you get 12 + 30 + 75 + 71 = 188s for rest to M1.5 at 35,000ft. Either way you lose by >30s. Give in yet?
Yeah, excluding the take off part, which is included in both sets of figures (BAE "Brakes off to M1.6 at 36,000ft" and Eurofighter tech guide "Brakes off to M1.5 at 35,000ft") and using a DI=0 and comparing it to a Typhoon with 8 missiles (and DTs too in reality - you can even verify this by examining the affect of different load-outs on the F-16's performance relative to clean!). So in reality, even when you cheat like mad you still lose.
I win not because you're tired it's because all your arguments were full of complete crap, and you used SEP as a substitute for true climb rate.
Where did I say EF was faster than MiG-25/31? Strawmanning. I said it was faster than M2.0. Never made such comments about the F-15E either.
In Love With the Blackbird
It is a race this jet will not let us lose. The Mach eases to 3.5 as we crest 80,000 feet. We are a bullet now - except faster. We hit the turn, and I feel some relief as our nose swings away from a country we have seen quite enough of. Screaming past Tripoli , our phenomenal speed continues to rise, and the screaming Sled pummels the enemy one more time, laying down a parting sonic boom. In seconds, we can see nothing but the expansive blue of the Mediterranean . I realize that I still have my left hand full-forward and we're continuing to rocket along in maximum afterburner.
The TDI now shows us Mach numbers, not only new to our experience but flat out scary. Walt says the DEF panel is now quiet, and I know it is time to reduce our incredible speed.
By: Andraxxus
- 8th October 2016 at 23:34Permalink- Edited 1st January 1970 at 01:00
^
Sarcasm aside isn't SR-71 faster than Mig-25/31?
Yes, but I wouldn't call SR-71 a combat aircraft; its a recon aircraft. Fastest combat aircrafts (which can carry weapons and utilize them) are MiG-31 and 25.
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By: Starfish Prime
- 9th October 2016 at 08:42Permalink- Edited 1st January 1970 at 01:00
It almost became a combat aircraft though but the AIM-54 made it unnecessary.
By: Peregrinefalcon
- 10th October 2016 at 00:25Permalink- Edited 1st January 1970 at 01:00
Do you even understand this diagram?
Let me see...
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.
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I won't comment on your assumption about 60° climb angle (it is only your assumption).
Aside from that, there is nothing wrong with your calculation. At constant speed of 398 m/s the plane would have actual climb rate of 345 m/s at 60° climb angle.
Here comes the interesting part:
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.
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Again, there is nothing wrong with your calculation.
So, for claimed climb rate of 315 m/s (actual climb rate), EF2000 needs to travel 364 m/s at 60° climb angle. And the most important part is where you claim that the plane at 364 m/s has 315 SEP.
Here comes your next quote:
You asked for climb rate, not SEP, you are again conflating the two. SEP != climb rate. The answer I provided was for the speed mentioned and that speed only. SEP is NOT Climb Rate!
Now comes the question, what is the difference between actual climb rate of 315 m/s and 315 m/s SEP in the case of EF2000 you have presented here?
And that's not all, next thing you do is looking at the chart to see the SEP for the same speed (364 m/s) for the Mig-29, and you find out that the SEP is 170 m/s. And in doing so, you concluded that the EF2000 has almost 2 times higher SEP for the same speed.
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Aside from trigonometry this all is so retarded that I don't know where to begin with...
Since in your case actual climb rate and SEP have the same value (315 m/s), how can you compare actual climb rate of one plane with the SEP from the other plane (because SEP is not actual climb rate)?
Second, how is it possible for two planes that travel at the same constant speed and at the same climb angle to have different rate of climb or SEP or whatever?
I'll now try to explain your stupidity!
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When we look at the Mig-29 "climb chart", we can see for example that at speed (306m/s) and see level, Mig-29 has energy potential (climb potential / 345 m/s) of additional 39m/s (positve SEP), which can be used for acceleration on a vertical climb. Record breaking F-15 demonstrates that perfectly (only the numbers are different). So, there is absolutely no doubt that the plane can accelerate in the vertical climb (as demonstrated) and can reach higher speed (m/s) compared to horizontal speed from which the climb has started.
Now, if we look for example at "climb rate" at Mach 1, we can see that the Mig-29 has climb potential of 260 m/s.
Is this the value for actual climb rate?
The plane is traveling at speed of 340 m/s (Mach 1), so we can conclude that at the bigining of the climb in short instant of time the plane will definitely have higher actual climb rate than 260 m/s, but since the plane has potential for 260 m/s at that height and speed, it will start to decelerate in the climb.
So, not me nor Andraxxus have ever claimed that looking at the chart every value is an actual climb rate!
Now, let's talk about you!
First things first, you are comparing apples and oranges.
You don't have "climb chart" for EF2000, and you are assuming that the plane is climbing at 60° climb angle.
Than you are using trigonometry for calculating the TAS from actuall/advertised climb rate.
You do have "climb chart" for Mig-29 and you are using the same TAS you have for EF2000 to find out the SEP for the MIG-29 at that speed.
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Do you see how retarded this is?!
First, two planes that travel at the same constant speed and at the same climb angle will have the same rate of climb.
Second, at 364 m/s the Eurofighter would suffer the same fate as Mig-29 because there is a high drag increase in transonic region at see level, and that is the main reason Mig-29 is having climb potential of 170 m/s.
So no, there is no chance in the World for EF2000 to have climb potential/SEP of 315 m/s at 364 m/s sea level, and no, EF2000 doesn't have almost TWO TIMES higher SEP at that speed!
And do I even have to say anything about you having incredibly contradicting statements which we can see from your quotes?!
By: garryA
- 10th October 2016 at 00:31Permalink- Edited 1st January 1970 at 01:00
When looking for Mig-29 manual ,i found this piece
Is it just me or the graph a bit off ? for example :in intatanous turn rate part , the 9 G envelope of Mig-29 is clearly bigger , why is F-16 evelope labed superior ? , and why the 9G sustain evelope of Mig-29 missing ?
P/S: manual for Russian AC is really hard to find
By: Andraxxus
- 10th October 2016 at 09:46Permalink- Edited 1st January 1970 at 01:00
Those graphs are very much like comparison of ballpark accurate F-16 data with (un)educated guesses regarding MiG-29.
I've only checked F-16's S/L, 20k and 30k STR graphs they seem to be similar, except they dont have 3 peaks, just 2 one at ~M0,9 and one at supersonic. Their ITR graph is also similar, it shows slighty better performance at 20k slightly worse at 40k. F-16 can pull 7+Gs at M2,05 point @ 40k.
MiG-29 is a mess however.
1-MiG-29's level flight (1G) envelope is a few pages behind and unlike this graph it shows;
-MiG-29 reaches its ceiling at M1,7, not at M1,9.
-low point in the middle of the envelope is at M1,15 not at M1,5.
-Top speed at 14km/45000 feet not at ~37000 feet.
-M2,3+ between 40000 and 52000 feet (though it may be just a tad slower with 2xR-60s, curvature should remain similar not sharp like this one)
2-If I am not mistaken I've posted 11km altitude sustained G vs Mach graph as well, it shows 3G is attainable at M0,9 40000k feet, and from M1,35+ to ~M2,1+. MiG-29 could almost pull 4Gs at 40k feet M1,9.
3-MiG-29 has 15 deg AOA and 7G limitation above M0,85. It simply cannot have such linear ITR envelope. There has to be a drop at M0,85 point, and 7+G points are all wrong.
4-Even for 13000kg (instead of 12500kg @50% fuel); 3G, 5G and 7G is sustainable at M0,27 M0,45 and M0,56 respectively. 9G is sustainable at M0,69.
5 MiG-29 do have a missing 9G envelope like you've said. @S/L 12500kg, 9G should be attainable from M0,66 to M0,85. at 3000 feet 9G is sustained between M0,73 and M0,85. If we interpolate, sustained 9G is possible only below ~6000 feet (M0,85).
IIRC MiG-29G manual for German Airforce was readily available on scribd or somewhere similar, it has performance data, but it mostly gives data on IAS, (instead of TAS) and makes it very difficult for comparisons above S/L. It does have some direct tranlations of Cl vs AOA and available G and available AOA graphs from Aerodynamics Manual, which are quite helpful. Unfortunately, I don't recall the whereabouts of the others. I've may not even got them from net too... To my knowledge, in addition to MiG-29G manual, I can confirm MiG-29 has a Russian flight manual, weapons manual, hydrolic&fuel subsystems manual and an aerodynamics manual. Hope this helps.
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By: Starfish Prime
- 10th October 2016 at 10:28Permalink- Edited 1st January 1970 at 01:00
Let me see...
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I won't comment on your assumption about 60° climb angle (it is only your assumption).
Aside from that, there is nothing wrong with your calculation. At constant speed of 398 m/s the plane would have actual climb rate of 345 m/s at 60° climb angle.
Here comes the interesting part:
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Again, there is nothing wrong with your calculation.
So, for claimed climb rate of 315 m/s (actual climb rate), EF2000 needs to travel 364 m/s at 60° climb angle. And the most important part is where you claim that the plane at 364 m/s has 315 SEP.
Here comes your next quote:
Now comes the question, what is the difference between actual climb rate of 315 m/s and 315 m/s SEP in the case of EF2000 you have presented here?
And that's not all, next thing you do is looking at the chart to see the SEP for the same speed (364 m/s) for the Mig-29, and you find out that the SEP is 170 m/s. And in doing so, you concluded that the EF2000 has almost 2 times higher SEP for the same speed.
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Aside from trigonometry this all is so retarded that I don't know where to begin with...
Since in your case actual climb rate and SEP have the same value (315 m/s), how can you compare actual climb rate of one plane with the SEP from the other plane (because SEP is not actual climb rate)?
Second, how is it possible for two planes that travel at the same constant speed and at the same climb angle to have different rate of climb or SEP or whatever?
I'll now try to explain your stupidity!
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When we look at the Mig-29 "climb chart", we can see for example that at speed (306m/s) and see level, Mig-29 has energy potential (climb potential / 345 m/s) of additional 39m/s (positve SEP), which can be used for acceleration on a vertical climb. Record breaking F-15 demonstrates that perfectly (only the numbers are different). So, there is absolutely no doubt that the plane can accelerate in the vertical climb (as demonstrated) and can reach higher speed (m/s) compared to horizontal speed from which the climb has started.
Now, if we look for example at "climb rate" at Mach 1, we can see that the Mig-29 has climb potential of 260 m/s.
Is this the value for actual climb rate?
The plane is traveling at speed of 340 m/s (Mach 1), so we can conclude that at the bigining of the climb in short instant of time the plane will definitely have higher actual climb rate than 260 m/s, but since the plane has potential for 260 m/s at that height and speed, it will start to decelerate in the climb.
So, not me nor Andraxxus have ever claimed that looking at the chart every value is an actual climb rate!
Now, let's talk about you!
First things first, you are comparing apples and oranges.
You don't have "climb chart" for EF2000, and you are assuming that the plane is climbing at 60° climb angle.
Than you are using trigonometry for calculating the TAS from actuall/advertised climb rate.
You do have "climb chart" for Mig-29 and you are using the same TAS you have for EF2000 to find out the SEP for the MIG-29 at that speed.
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Do you see how retarded this is?!
First, two planes that travel at the same constant speed and at the same climb angle will have the same rate of climb.
Second, at 364 m/s the Eurofighter would suffer the same fate as Mig-29 because there is a high drag increase in transonic region at see level, and that is the main reason Mig-29 is having climb potential of 170 m/s.
So no, there is no chance in the World for EF2000 to have climb potential/SEP of 315 m/s at 364 m/s sea level, and no, EF2000 doesn't have almost TWO TIMES higher SEP at that speed!
And do I even have to say anything about you having incredibly contradicting statements which we can see from your quotes?!
Yes and the MiG-29 does not have 345m/s SEP at 398m/s in level flight at low altitude. That's been my point all along.
Because at 364m/s the EF satisfies the Vsin(gamma) = hdot = 315m/s as well as having a SEP of 315m/s. At 306m/s or M0.9, the MiG-29 cannot possibly satisfy the Vsin(gamma) = hdot = 345m/s equation.
You can't compare SEP and climb rate because they are different, except at very specific points. The MiG-29's maximum rate of climb will be achieved at a low speed and hence will likely be lower.
The MiG-29 can't sustain climb at the same angle at that speed (364m/s or M1.07), that's what the SEP chart of the MiG-29 tells you.
Nope, because as the MiG-29 gains speed from 306m/s, its SEP decays because drag has increased. SEP = V*[(T-D)/W]. D is drag, D increases as V increases via D = 0.5*Density*Area*Cd*V^2. So above 306m/s the MiG-29 can only climb at whatever rate the SEP chart says it has left assuming that Vsin(gamma) = hdot, which it may not do, in which case speed continues increasing and SEP falls further still.
At 340m/s the MiG-29 has 260m/s SEP, so at a climb angle of 50deg, it can manage a sustained 260m/s climb.
Yes, Andraxxus did, you review the start of this conversation. He claimed an actual climb rate of 345m/s for the MiG-29.
Very true, 60deg is an approximation. It might very well be M0.95 at a 77deg angle.
Never implied that, I said the MiG-29 only had 170m/s SEP at that speed, I made no mention of its maximum climb angle. This infers the maximum sustained climb angle at that speed is lower.
Except the EF is specifically designed for reduced wave drag. And as I said, 60deg was an approximation and in the F-15 video it climbed at 55deg.
I haven't made any contradicting statements, simply showing why Andraxxus is wrong.
I should also mention at this stage the origin of the 315m/s EF figure. It's based on a statement of a climb rate >25% better than an F-16, which is rated at >254m/s (50,000ft/min), giving >318m/s. Elsewhere however, I found this for the F-16.
By: garryA
- 10th October 2016 at 10:47Permalink- Edited 1st January 1970 at 01:00
.2-If I am not mistaken I've posted 11km altitude sustained G vs Mach graph as well, it shows 3G is attainable at M0,9 40000k feet, and from M1,35+ to ~M2,1+. MiG-29 could almost pull 4Gs at 40k feet M1,9.
Are you referring to this? ( indeed very hard to compare with F-16 or any western fighter data)
.IIRC MiG-29G manual for German Airforce was readily available on scribd or somewhere similar, it has performance data, but it mostly gives data on IAS, (instead of TAS) and makes it very difficult for comparisons above S/L. It does have some direct tranlations of Cl vs AOA and available G and available AOA graphs from Aerodynamics Manual, which are quite helpful. Unfortunately, I don't recall the whereabouts of the others. I've may not even got them from net too... To my knowledge, in addition to MiG-29G manual, I can confirm MiG-29 has a Russian flight manual, weapons manual, hydrolic&fuel subsystems manual and an aerodynamics manual. Hope this helps.
I found the manual for German Mig-29 (GAF T.O. 1-F-MIG-29-1) sadly it all about instructions and instruments, cant find any performance data
I actually found Mig-29 aerodynamic manual, too bad it is in Russian and they dont use the same E-M graph as Western one so i have no idea what heck they talking about lol.
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By: Peregrinefalcon - 5th October 2016 at 21:52 Permalink - Edited 1st January 1970 at 01:00
Sure we are, but just to make some things clear...
If I'm understanding you correctly, let's say for example that the plane X travels at 187 m/s at sea level. The actual max climb rate at ~60° climb angle for the X plane should be ~162,6 m/s according to your calculation method?
Am I right?
And if I'm wrong, can you calculate for me the max climb rate for the X plane at 60 and 90° climb angle?
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By: Andraxxus - 6th October 2016 at 02:25 Permalink - Edited 1st January 1970 at 01:00
Peregrinefalcon's NASA quote explains it better;
The with zero excess power flies in Thrust = drag condition. If thrust is higher than drag (or lower), there will be a force (kg*m/s^2) on a moving object (m/s), there will be a rate of increase in energy in Joule/s, or kg*m^2/s^2 to write it in a more open form.
Thermodynamics law: Total energy of the system = Kinetic energy of system + Potential energy of system + internal energy of the system.
This law can apply to everything, and if we consider whole aircraft as this thermodynamic system, internal energy won't change (ie, aircraft won't heat up etc). So equation becomes E = KE+PE.
As a performance parameter, we are looking on rate of kinetic energy change or potential energy change, so we take the differential of both sides;
rate of energy change(dE) = dKE (rate of KE change) + dPE (rate of PE change).
Power = mass*Velocity*dVelocity + mass*G*dHeight.
dVelocity = rate of change in velocity, which means acceleration
dHeight = rate of change in height, which means climb rate.
divide both sides by mass and there is;
Specific Power = velocity*acceleration + G*climb rate.
Now as I've written above specific power has no meaning for the pilot; Some 1000 watt/kg is not a quantifiable measurement for him. So instead of giving such performance parameter, we divide both sides with G so we have
Climb-rate/potential (as performance parameter) = velocity*acceleration/G + climb rate (as in aircrafts actual change in height).
Now if you are flying at 300 m/s, and you have 200 m/s climb rate as written in the manual, this means you can climb at 200m/s without losing speed. You can surely go 90deg vertical and climb at 300m/s for an instant, but accordingly to this -scalar- energy equation you would be trading KE (slowing down) for this rate of increase in PE. Likewise, you can climb at 100m/s and accelerate at the same time (both KE and PE increase). Or you can stick at 0m/s climb rate (dPE = 0) and climb rate will mathematically give the level flight acceleration of the aircraft. On descent rate of PE change is also added to the rate of KE change.
Even if you are flying at 309 m/s, an aircraft can surely have 345m/s climb rate. A SAM recently launched and flying 20-30 m/s can even have 500+ m/s climb rate. This climb rate is a mere representation of energy change of aircraft, which pilot can use in any combination of KE and PE change.
If climb rate is equal to aircraft's speed, this means aircraft can climb at 90 degree angle and won't speed up or slow down. If its higher, than this excess climb-potential will result in KE change, which means acceleration on vertical climb.
Despite it says "climb rate" graph its solely related with energy and should be read with caution: if a MiG-29 wants to make a quick climb from 11 km altitude, actual climb rate won't be highest around 180m/s @M1,7. It will be highest at M2,3 @ 678 m/s when MiG-29 makes an exact 90 degree vertical climb (assuming no direction change delays). But since MiG-29 has only 60m/s climb rate at that speed, it will see a quick deceleration equivalent to (60-678) m/s climb rate; 60-678 = v*a/g = -8,94 m/s^2 deceleration. Assuming constant deceleration, it will slow down to below M2,0 just within 10 seconds, but will have 633 m/s average climb rate during that time, to ascend it to 17km altitude.
For aerodynamics 101 this does not matter, as people are teached without this background, examplified by something with puny climb rates like B-737 or something, so certain know-it-all people can easily calculate angle from simple trigonometry. Its perfectly ok, but gets unamusing when they draw conclusions and making assumptions about all aircraft should climb at 60 degrees so climb rate will give an imaginary speed and draw even more conclusions from that.
Climb rate/potential is also variable with dynamic thrust, L/D and how much G aircraft pulls (which is also independent of aircraft weight), and its shown as lines for Energy-maneuverability diagram F-16 manual for example. In a sense, that diagram doesn't only show ITR and STR, it also shows the vertical play and acceleration capability of the F-16 as well. As energy is a scalar quantity (instead of vectoral), one an use this graph to say F-16 at Mach A pulling B amount of Gs can climb/descent C amount of meters and accelerate/decelerate by D amount.
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By: Starfish Prime - 6th October 2016 at 08:43 Permalink - Edited 1st January 1970 at 01:00
Yes, unless the plane changes airspeed. 60deg is an approximation, it will vary depending on aircraft. I actually get 161.95m/s at 60deg and obviously 187m/s at 90deg.
http://www.dept.aoe.vt.edu/~lutze/AOE3104/climb.pdf
http://www.srmuniv.ac.in/sites/default/files/downloads/class12-2012.pdf
https://www.aircraftspruce.com/catalog/pdf/13-09981.pdf
SEP = Ability to gain Energy
Not specifically PE. The maximum actual sustained ascent rate at any speed is:
hdot = V*sin(alpha)
The maximum rate of climb is attained when this equation is at its highest and when:
V*([T-D]/W) is equal to the same value.
If V is not high enough, such that Vsin(alpha) != hdot
Then it does not stand as a legitimate climb rate, it is simply specific excess power and a measure of how much combined KE+PE an aircraft can gain from a given airspeed at peak thrust.
The first link shows how the optimum airspeed and angle is derived for a given aircraft.
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By: Starfish Prime - 6th October 2016 at 09:08 Permalink - Edited 1st January 1970 at 01:00
Nope, up to the bit in bold you were doing so well.
You are trying to conflate SEP and Climb Rate.
You had it here:
rate of energy change(dE) = dKE (rate of KE change) + dPE (rate of PE change).
I.e.
SEP = [dPE/dt + dKE/dt]/mg = dh/dt + (V/g)*(dV/dt)
It is not a measure of potential to climb but potential to climb + potential to accelerate.
You can't turn it all to climb rate unless you satisfy V*sin(alpha) = hdot.
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By: Peregrinefalcon - 6th October 2016 at 16:10 Permalink - Edited 1st January 1970 at 01:00
Ok, that is all I need to know because the numbers for the X plane in my example are not used randomly, there is reason to it.
Since other explanations and charts by Andraxxus and NASA are not good enough for you I have this:
Here is the real world example where we can see that the (record breaking) F-15 at 420 mph on the deck (~187 m/s), has enough SEP to break the speed of sound (~340m/s) at 90° climb angle.
You can also see that at 450 mph (~200 m/s) and 55° climb angle the plane is accelerating through the speed of sound!
This is all in the line with explanations Andraxxus gave in the above post and examples I provided. On the other hand your calculations are so wrong it is beyond comprehension. You actually concluded that EF2000 has almost two times better climb rate than Mig-29:
The only thing you should rest is this debate :rolleyes:
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By: Starfish Prime - 7th October 2016 at 10:04 Permalink - Edited 1st January 1970 at 01:00
You're still conflating SEP and rate of climb.
You cannot climb at X m/s unless Vsin(alpha) = X, this is a basic fact.
http://www.dept.aoe.vt.edu/~lutze/AOE3104/climb.pdf
The video says the aircraft is at 450mph, pulls up into a 55deg climb and 25s later it is accelerating through the speed of sound (3:30).
So we see that SEP was converted into both d(KE/dt) and d(PE/dt). It did not reach maximum climb rate at 450mph, it accelerated and gained speed first.
At M0.9 (306m/s) the MiG-29 has a SEP of 345m/s, this cannot all be converted to climb rate at this speed, it must first gain speed, after which it will reach a point of greater velocity, where the remaining SEP is converted to climb rate.
You're arguing a point you don't understand with zero comprehension of physics. Basically, you're trolling.
Posts: 427
By: Peregrinefalcon - 7th October 2016 at 20:22 Permalink - Edited 1st January 1970 at 01:00
Now, I intentionally asked you what climb rate would plane X have at 187 m/s on the deck for 60 and 90° climb angle and you answered (as I thought you would) 162 and 187 m/s.
First of all, answering that question without knowing a single thing about planes technical characteristics (since we are talking about plane X) is retarded by itself.
Second, the real world example is undoubtedly showing that numbers you provided have no base in reality.
The video shows that F-15 at 187 m/s on the deck has potential (climb potential or specific excess power - see NASA paper) to climb at much higher rate than 187 m/s at 90° climb angle. The plane has enough specific excess power to accelerate through the speed of sound in the vertical climb.
Now, if we had Boing 747 performing the same thing at 187 m/s, situation would be much different ;)
First of all, he is not accelerating through the speed of sound 25 seconds after pulling into the climb, he is reaching that speed 25 seconds after the brake release.
Really, let me think...the plane didn't reach its max climb rate while flying horizontally at 450 mph...it had to actually go in to the climb, accelerate in the climb and only then it reached its max climb rate!
Wow, I think you are genius :rolleyes:
On the serious note, this only shows that the plane has potential (climb potential) to accelerate in the climb (55 and 90° climb angle) at that particular speed.
And what is the climb potential?
"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".
It is the same thing as with F-15 in the video I posted. At that speed (306m/s), Mig-29 has energy potential (climb potential) of additional 39m/s (positve SEP), which can be used for acceleration on a vertical climb. Record breaking F-15 demonstrates that perfectly (only the numbers are different).
Now, if we assume that EF2000 has its best climb rate of 315 m/s at 0,9M, (same speed as Mig-29), that meens that it has energy potential (climb potential) of additional 9 m/s (positve SEP), which can be used for acceleration on a vertical climb.
But somehow, you with your perfect understanding of the subject concluded that EF2000 has almost TWO TIMES higher climb rate than Mig-29.
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By: Starfish Prime - 8th October 2016 at 09:20 Permalink - Edited 1st January 1970 at 01:00
I stated that the angle of climb varies but is usually ~60deg for a fighter class aircraft. I have several times posted a link detailing how V optimum and alpha optimum are calculated, so please don't try pretend you're clever.
http://www.dept.aoe.vt.edu/~lutze/AOE3104/climb.pdf
You asked for climb rate, not SEP, you are again conflating the two. SEP != climb rate. The answer I provided was for the speed mentioned and that speed only. SEP is NOT Climb Rate!
It says, "after release", that could mean brakes off or take off. Either way, it's well known that the Streak Eagle was a non-standard aircraft. Stripped of nearly all avionics, even paint and had uprated thrust. TWR was over 2:1 on empty weight.
Yes, but sadly you are not a genius, which is why I've been trying to explain this very point to both you and Andraxxus for several pages. SEP at a given speed does not equal climb rate at that speed or maximum climb rate. It is a measure of the ability to gain speed and altitude. Unless Vsin(alpha optimum) equals climb rate then the SEP at that V does not equal climb rate.
Nope, you're still not getting it. The SEP at 450mph was not all converted to climb rate, some was converted to velocity (KE). As per the following:
SEP = [dPE/dt + dKE/dt]/mg = dh/dt + (V/g)*(dV/dt)
As speed increased, SEP decreased, but the V was then sufficient to achieve the optimum climb rate and the remaining SEP could be converted to climb rate.
No because as the speed of the MiG increases, drag increases and the SEP, given by:
V*([T-D]/W)
Therefore reduces.
Seriously how can V*([T-D]/W) be the same at M0.9 as say M1.2?
The graph clearly shows the SEP at SL is zero at M1.2, so how can it climb at say a 55deg angle at the latter speed? And even if it did, it would only achieve 334m/s climb rate by Vsin(alpha)*.
(*I apologise for using alpha, it's confusing, as it's usually used to refer to AoA but here I use it as the angle of ascent.)
I never said it had twice the climb rate, I said it had nearly twice the SEP at a given speed. There is a difference, as I've been trying to point out.
Come back when you really understand this post and the subject matter, because it's clear to all that you don't.
Do you even understand this diagram?
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By: Andraxxus - 8th October 2016 at 11:52 Permalink - Edited 1st January 1970 at 01:00
You have once again my point of twisting data and being an dishonorable LIAR!!.
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1- Eurofighter.com says "with a full Air-to-Air Missile fit." It says f**ng missiles. No 1000l fuel tanks. It actually doesn't even say full internal fuel, I assume as such for the sake of argument and comparison; If an F-16 beats or matches Typhoon performance with 100% fuel, that it will certainly beat it in lesser fuels. Since F-16 does just that, I don't bother an argument of how much fuel Typhoon may be carrying, it doesn't matter if its 100%.
2- Eurofighter.com says 200kts to M1,0, NOT from "brakes off". And NO "<30" seconds it says "in 30 seconds", not "less than" or "under". I don't need to add a milisecond because F-16 manual gives EXACTLY that; with full fuel and A-A payload, from 200kts to M1,0 in 29,3 seconds.
3- BAE systems website does NOT even say "with full Air to Air payload" like Eurofighter official website do, let alone your 3x drop tanks BS. You are take a claim from Eurofighter website, inflate it with your BS (this time by adding 3x1000l tanks), then you try to pass it as something taken from BAE's website.... Most (actually the ONLY) logical explaination for this contradicting data between two official sources is BAE system give data for Typhoon with much lighter payloads.
1-brakes off to 35k feet M1,5 under 2,5 minutes with full A-A missile fit.
2-brakes off to 36k feet M1,6 under 2,5 minutes with unknown payload... Maybe for a clean aircraft with 50% or even less fuel.
1-200kts to M1,0 in 30 seconds with full A-A fit.
2-brakes off to M1,0 under 30 seconds with unknown payload.
For the 1st claims, F-16 beats Typhoon in acceleration and *MAYBE* just a few seconds slower in climb. I am not so certain its slower as I didn't do an optimal climb profile.
I don't have a comparison basis for the 2nd claims, and I simply ignore them, and I have no idea why you keep bringing these up (like you did two years ago with your "Lukos" alias). Payload and fuel is VERY important to make a valid comparison.
No fuel and payload criteria? Then it doesn't tell anything about the performance of the aircraft.. Even an F-4 can climb from 0 to 35000 feet in 42 seconds given its light enough. I won't do the whole math, but this sufficently light F-4 could probably take-off and make necessary accelerations in the remaining 208 seconds, maybe miss it by a 5-10 seconds at best.
A simple "take off, accelerate to M0,9 climb to 35k feet, accelerate to M1,5" profile takes 150 seconds on F-16 excluding the 8-12 second take off part. For the 300th time, F-16 can achieve better climb time above 20k feet if its supersonic (instead of keep climbing at M0,9). It also accelerates to M0,9 to M1,5 full 13 seconds faster at this altitude (53 seconds @20k feet vs 66 seconds@30k feet), so it can shave quite a few seconds from that overly simplistic 150 second time.
I can make time calculations for this relatively more optimal climb profile for F-16, and Climb and Acceleration time is perfectly calculable from climb-rate graph of MiG-29, but I don't think anyone else is interested, and I won't waste my 50 minutes for you. My point is crystal clear; Typhoon is only an even match for a Block 50 F-16 at best, and MiG-29A has 22% to 62% better 1G excess power compared to same F-16.
I don't have any stomach left to discuss with you. You win OK? I was wrong and this Lukos/Starfish guy was right all along..
Starfish/Lukos says:
-Su-27S has the highest (subsonic) sustained turn rates of all 4th gen fighters at mid-high altitude, but Typhoon has it better.
-Su-27S has the highest (subsonic) sustained turns of all 4th gen aircraft when fuel weight is equalised for same range, but Typhoon is better.
-F-16 blk30 has the highest (subsonic) sustained turn rate among all a 4th gen fighter with 50% fuel, but Typhoon is better.
-MiG-29 has the greatest (subsonic) climb rate value among all 4th gen fighters, and greatest off-the-deck climb performance, but Typhoon is better.
-MiG-25 and MiG-31 are the fastest combat aircraft ever entered service, but Typhoon is faster than those when carrying EFTs (M2,0 vs M1,7 and M1,5 for MiG-25 and MiG-31 respectively)
-F-15E with PW-229 is the fastest fighter aircraft with heavy payloads, yet Typhoon with 8 missiles and 3 EFTs is faster than F-15E with 8 missiles and no EFTs but only CFTs (M2,0 vs M1,9).
All that subsonic performance, despite the fact Typhoon is designed for high-altitude supersonic regime.
All that impressive high mach top speeds with EFTs, despite puny 90kN engines and a fixed inlet.
These should say how Typhoon is the bestest product mankind has ever made. Happy now?
Speaking of climbs, a nice video of MiG-29's off the deck climb with centerline fuel tank (this is the first time I've mentioned this fuel tank, since we are idiot enough to think every hanging EFT is fully loaded with fuel during airshows)
https://youtu.be/VCWjByenDsM?t=40s
Not that I would claim for a second Typhoon is any worse than that of course. Even without no evidence, Typhoon is better because it is the bestest aircraft.
Posts: 1,081
By: garryA - 8th October 2016 at 12:16 Permalink - Edited 1st January 1970 at 01:00
^
Sarcasm aside isn't SR-71 faster than Mig-25/31?
Posts: 949
By: Starfish Prime - 8th October 2016 at 15:37 Permalink - Edited 1st January 1970 at 01:00
1. Full AAM fit is basically the standard QRA load, which is 4xAMRAAM + 4xASRAAM + 3x1000L DTs. It's evidently a lot slower than the clean figures BAE provides, so DI is certainly not zero.
2. Irrelevant, the BAE figures are for the clean aircraft, the GmbH figures are for a loaded aircraft. You can argue about the load all day but clearly it is loaded and the DI is not zero.
3. That's because the BAE figures are clean, just as the original F-16 figures were. That's what DI=0 means remember.
The 'unknown payload' is clean. DI=0. The GmbH load is DI !=0 and likely implies the standard QRA fit given the performance delta with the clean figures.
Yeah, because for the first claim you are comparing DI=0 with DI != 0. When you compare DI=0 with DI=0, the Typhoon wins by over 30s. How seriously disingenuous of you.
Sure you do, you have the DI=0 figures. And even at 20,000lbs GW (i.e. less than empty, empty weight was actually over 20,168lb, so they must have removed stuff https://info.publicintelligence.net/HAF-F16-Supplement.pdf), the F-16 can't get from brakes off to M1.0 in <30s. 19s from M0.3-1.0 + ~12s for M0.0-0.3 gives 31s. Get the picture yet?
At 24,000lb GW, which is about half fuel only, it's at 34s M0.0-0.98 and still can't beat the Typhoon to M1.6 and 36,000ft. So like I said, "no way, no how!" You just can't accept that you're wrong.
The load is now irrelevant because I just proved that even at sub-empty weight the F-16 can't beat the Typhoon to M1.0. And as far as that goes, the Eurofighter tech guide doesn't specify fuel load either, it's just assumed that it starts with full internal fuel on your part, whereas it's likely the standard QRA fit, since that would be the most applicable to customers.
Even if we play, the no DTs dice, it's still 8 AAMs, so we'll use the 30,000lb ground weight with DI=50 for the F-16 (which is still a lower fuel fraction and even 2 AIM-9Ls on pylons and adaptors has a DI of 22 and there will be 6 missiles on such, with 2 on the wing tips). I'm also letting you off on weight a little too. And you get 12 + 30 + 75 + 71 = 188s for rest to M1.5 at 35,000ft. Either way you lose by >30s. Give in yet?
Yeah, excluding the take off part, which is included in both sets of figures (BAE "Brakes off to M1.6 at 36,000ft" and Eurofighter tech guide "Brakes off to M1.5 at 35,000ft") and using a DI=0 and comparing it to a Typhoon with 8 missiles (and DTs too in reality - you can even verify this by examining the affect of different load-outs on the F-16's performance relative to clean!). So in reality, even when you cheat like mad you still lose.
I win not because you're tired it's because all your arguments were full of complete crap, and you used SEP as a substitute for true climb rate.
Where did I say EF was faster than MiG-25/31? Strawmanning. I said it was faster than M2.0. Never made such comments about the F-15E either.
Took way longer than Typhoon to take-off.
https://www.youtube.com/watch?v=zC89uDi8mEg
https://www.youtube.com/watch?v=tkP2dfjjgCg
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By: Starfish Prime - 8th October 2016 at 15:47 Permalink - Edited 1st January 1970 at 01:00
Yes. Pilots confirm speeds of over M3.5.
http://sploid.gizmodo.com/5511236/the-thrill-of-flying-the-sr-71-blackbird
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By: Andraxxus - 8th October 2016 at 23:34 Permalink - Edited 1st January 1970 at 01:00
Yes, but I wouldn't call SR-71 a combat aircraft; its a recon aircraft. Fastest combat aircrafts (which can carry weapons and utilize them) are MiG-31 and 25.
Posts: 949
By: Starfish Prime - 9th October 2016 at 08:42 Permalink - Edited 1st January 1970 at 01:00
It almost became a combat aircraft though but the AIM-54 made it unnecessary.
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By: Peregrinefalcon - 10th October 2016 at 00:25 Permalink - Edited 1st January 1970 at 01:00
Let me see...
[ATTACH=CONFIG]248788[/ATTACH]
I won't comment on your assumption about 60° climb angle (it is only your assumption).
Aside from that, there is nothing wrong with your calculation. At constant speed of 398 m/s the plane would have actual climb rate of 345 m/s at 60° climb angle.
Here comes the interesting part:
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Again, there is nothing wrong with your calculation.
So, for claimed climb rate of 315 m/s (actual climb rate), EF2000 needs to travel 364 m/s at 60° climb angle. And the most important part is where you claim that the plane at 364 m/s has 315 SEP.
Here comes your next quote:
Now comes the question, what is the difference between actual climb rate of 315 m/s and 315 m/s SEP in the case of EF2000 you have presented here?
And that's not all, next thing you do is looking at the chart to see the SEP for the same speed (364 m/s) for the Mig-29, and you find out that the SEP is 170 m/s. And in doing so, you concluded that the EF2000 has almost 2 times higher SEP for the same speed.
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Aside from trigonometry this all is so retarded that I don't know where to begin with...
Since in your case actual climb rate and SEP have the same value (315 m/s), how can you compare actual climb rate of one plane with the SEP from the other plane (because SEP is not actual climb rate)?
Second, how is it possible for two planes that travel at the same constant speed and at the same climb angle to have different rate of climb or SEP or whatever?
I'll now try to explain your stupidity!
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When we look at the Mig-29 "climb chart", we can see for example that at speed (306m/s) and see level, Mig-29 has energy potential (climb potential / 345 m/s) of additional 39m/s (positve SEP), which can be used for acceleration on a vertical climb. Record breaking F-15 demonstrates that perfectly (only the numbers are different). So, there is absolutely no doubt that the plane can accelerate in the vertical climb (as demonstrated) and can reach higher speed (m/s) compared to horizontal speed from which the climb has started.
Now, if we look for example at "climb rate" at Mach 1, we can see that the Mig-29 has climb potential of 260 m/s.
Is this the value for actual climb rate?
The plane is traveling at speed of 340 m/s (Mach 1), so we can conclude that at the bigining of the climb in short instant of time the plane will definitely have higher actual climb rate than 260 m/s, but since the plane has potential for 260 m/s at that height and speed, it will start to decelerate in the climb.
So, not me nor Andraxxus have ever claimed that looking at the chart every value is an actual climb rate!
Now, let's talk about you!
First things first, you are comparing apples and oranges.
You don't have "climb chart" for EF2000, and you are assuming that the plane is climbing at 60° climb angle.
Than you are using trigonometry for calculating the TAS from actuall/advertised climb rate.
You do have "climb chart" for Mig-29 and you are using the same TAS you have for EF2000 to find out the SEP for the MIG-29 at that speed.
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Do you see how retarded this is?!
First, two planes that travel at the same constant speed and at the same climb angle will have the same rate of climb.
Second, at 364 m/s the Eurofighter would suffer the same fate as Mig-29 because there is a high drag increase in transonic region at see level, and that is the main reason Mig-29 is having climb potential of 170 m/s.
So no, there is no chance in the World for EF2000 to have climb potential/SEP of 315 m/s at 364 m/s sea level, and no, EF2000 doesn't have almost TWO TIMES higher SEP at that speed!
And do I even have to say anything about you having incredibly contradicting statements which we can see from your quotes?!
Posts: 1,081
By: garryA - 10th October 2016 at 00:31 Permalink - Edited 1st January 1970 at 01:00
When looking for Mig-29 manual ,i found this piece
Is it just me or the graph a bit off ? for example :in intatanous turn rate part , the 9 G envelope of Mig-29 is clearly bigger , why is F-16 evelope labed superior ? , and why the 9G sustain evelope of Mig-29 missing ?
P/S: manual for Russian AC is really hard to find
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By: Andraxxus - 10th October 2016 at 09:46 Permalink - Edited 1st January 1970 at 01:00
Those graphs are very much like comparison of ballpark accurate F-16 data with (un)educated guesses regarding MiG-29.
I've only checked F-16's S/L, 20k and 30k STR graphs they seem to be similar, except they dont have 3 peaks, just 2 one at ~M0,9 and one at supersonic. Their ITR graph is also similar, it shows slighty better performance at 20k slightly worse at 40k. F-16 can pull 7+Gs at M2,05 point @ 40k.
MiG-29 is a mess however.
1-MiG-29's level flight (1G) envelope is a few pages behind and unlike this graph it shows;
-MiG-29 reaches its ceiling at M1,7, not at M1,9.
-low point in the middle of the envelope is at M1,15 not at M1,5.
-Top speed at 14km/45000 feet not at ~37000 feet.
-M2,3+ between 40000 and 52000 feet (though it may be just a tad slower with 2xR-60s, curvature should remain similar not sharp like this one)
2-If I am not mistaken I've posted 11km altitude sustained G vs Mach graph as well, it shows 3G is attainable at M0,9 40000k feet, and from M1,35+ to ~M2,1+. MiG-29 could almost pull 4Gs at 40k feet M1,9.
3-MiG-29 has 15 deg AOA and 7G limitation above M0,85. It simply cannot have such linear ITR envelope. There has to be a drop at M0,85 point, and 7+G points are all wrong.
4-Even for 13000kg (instead of 12500kg @50% fuel); 3G, 5G and 7G is sustainable at M0,27 M0,45 and M0,56 respectively. 9G is sustainable at M0,69.
5 MiG-29 do have a missing 9G envelope like you've said. @S/L 12500kg, 9G should be attainable from M0,66 to M0,85. at 3000 feet 9G is sustained between M0,73 and M0,85. If we interpolate, sustained 9G is possible only below ~6000 feet (M0,85).
IIRC MiG-29G manual for German Airforce was readily available on scribd or somewhere similar, it has performance data, but it mostly gives data on IAS, (instead of TAS) and makes it very difficult for comparisons above S/L. It does have some direct tranlations of Cl vs AOA and available G and available AOA graphs from Aerodynamics Manual, which are quite helpful. Unfortunately, I don't recall the whereabouts of the others. I've may not even got them from net too... To my knowledge, in addition to MiG-29G manual, I can confirm MiG-29 has a Russian flight manual, weapons manual, hydrolic&fuel subsystems manual and an aerodynamics manual. Hope this helps.
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By: Starfish Prime - 10th October 2016 at 10:28 Permalink - Edited 1st January 1970 at 01:00
Yes and the MiG-29 does not have 345m/s SEP at 398m/s in level flight at low altitude. That's been my point all along.
Because at 364m/s the EF satisfies the Vsin(gamma) = hdot = 315m/s as well as having a SEP of 315m/s. At 306m/s or M0.9, the MiG-29 cannot possibly satisfy the Vsin(gamma) = hdot = 345m/s equation.
You can't compare SEP and climb rate because they are different, except at very specific points. The MiG-29's maximum rate of climb will be achieved at a low speed and hence will likely be lower.
The MiG-29 can't sustain climb at the same angle at that speed (364m/s or M1.07), that's what the SEP chart of the MiG-29 tells you.
Nope, because as the MiG-29 gains speed from 306m/s, its SEP decays because drag has increased. SEP = V*[(T-D)/W]. D is drag, D increases as V increases via D = 0.5*Density*Area*Cd*V^2. So above 306m/s the MiG-29 can only climb at whatever rate the SEP chart says it has left assuming that Vsin(gamma) = hdot, which it may not do, in which case speed continues increasing and SEP falls further still.
At 340m/s the MiG-29 has 260m/s SEP, so at a climb angle of 50deg, it can manage a sustained 260m/s climb.
Yes, Andraxxus did, you review the start of this conversation. He claimed an actual climb rate of 345m/s for the MiG-29.
Very true, 60deg is an approximation. It might very well be M0.95 at a 77deg angle.
Never implied that, I said the MiG-29 only had 170m/s SEP at that speed, I made no mention of its maximum climb angle. This infers the maximum sustained climb angle at that speed is lower.
Except the EF is specifically designed for reduced wave drag. And as I said, 60deg was an approximation and in the F-15 video it climbed at 55deg.
I haven't made any contradicting statements, simply showing why Andraxxus is wrong.
I should also mention at this stage the origin of the 315m/s EF figure. It's based on a statement of a climb rate >25% better than an F-16, which is rated at >254m/s (50,000ft/min), giving >318m/s. Elsewhere however, I found this for the F-16.
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By: garryA - 10th October 2016 at 10:47 Permalink - Edited 1st January 1970 at 01:00
Are you referring to this? ( indeed very hard to compare with F-16 or any western fighter data)
I found the manual for German Mig-29 (GAF T.O. 1-F-MIG-29-1) sadly it all about instructions and instruments, cant find any performance data
I actually found Mig-29 aerodynamic manual, too bad it is in Russian and they dont use the same E-M graph as Western one so i have no idea what heck they talking about lol.
Posts: 1,081
By: garryA - 10th October 2016 at 12:14 Permalink - Edited 1st January 1970 at 01:00
Isnt F-16 also structure limited to 8.5G above Mach 0.65 according to this ? or do i read it wrong ?