By: Sens
- 13th June 2008 at 14:22Permalink- Edited 1st January 1970 at 01:00
Yefim Gordon's Aerofax book has:
Su-24M
MTOW - 39700 kg
Empty - 22300 kg
Payload: 8000 kg
Leaves 9400 kg for fuel
Fuel is carried in three internal tanks
No. 1: 3220 L (some early series SU-24 had 2220 L)
No. 2: 2950 L
No. 3: 4890 L
Total: 11060 L x 0.785 = 8682 kg
Looks about right.
In 1975 they locked the inlets on the earlier Su-24 - this saved maintenance and 236 kg weight. Maximum speed was limited as a result.
Note the Sukhoi link: http://www.sukhoi.org/eng/planes/military/su24mk/lth/ says 11060 kg, but it also has:
11,200 kg engine thrust in full power (actually 7800 kg per engine)
111,200 kg afterburner thrust! (actually 11,200 kg per engine)
Are someone unable to read data in a correct way.
From producer:
Takeoff weight:
- normal, kg 38,040
- maximum, kg 43,755
Normal ordnance load, kg 3,000
Maximum ordnance load, kg 8,000
The first value is with 3 tons normal weapons load.
The second value is with 8 tons weapons load.
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By: MiG-23MLD
- 13th June 2008 at 22:53Permalink- Edited 1st January 1970 at 01:00
Get a book about aircraft (preferably one of those without pictures) and read it.
Static thrust has nothing to do with supersonic thrust, the only thing we can guess from it is the region. F-111, Tornado and Su-24 play in one league, but the F-16 is two leagues higher.
Flow distortion is no problem as long as we fly straight ahead, and actually only the early engines and the A-model was affected. No problem on the F version.
The key word is "pressure recovery factor".
Recommendation: Copy&Paste into Google, see what you find.
Schorsch
Since the moment i said the inlet is the main factor to judge if the Su-24 can or can not reach Mach 2 i know even the basics to say the AL-21 needs pressure recovery, since the engine demands the less drag possible and a specific flow of air.
The F-16 as the Su-24 won`t fly Mach 2 at low altitude, so certainly they will fly at mach 2 at similar conditions and not at low altitude, the inlet design and the engine in the F-16 are flexible enough to accept the flow conditions in the inlet to work properly, the F-16 does not need a VG ramp inlet to work well, the Ukranian air force webpage and some other sources claim a speed of Mach 2, the same speed the F-16 can reach at 12000 meters of altitude and certainly besides the F-16`s inlet is of D shape and the Su-24 is of rectangular shape, they are not very different from each other creating shock waves to disaccelerate the air flow to subsonic speeds.
Besides military turbofans are low by pass ratio engines not very different from turbojets after all
By: Sens
- 13th June 2008 at 23:38Permalink- Edited 1st January 1970 at 01:00
Schorsch
Since the moment i said the inlet is the main factor to judge if the Su-24 can or can not reach Mach 2 i know even the basics to say the AL-21 needs pressure recovery, since the engine demands the less drag possible and a specific flow of air.
The F-16 as the Su-24 won`t fly Mach at low altitude, so certainly they will fly at mach 2 at similar conditions and not at low altitude, the inlet design and the engine in the F-16 are flexible enough to accept the flow conditions in the inlet to work properly, the F-16 does not need a VG ramp inlet to work well, the Ukranian air force webpage and some other sources claim a speed of Mach 2, the same speed the F-16 can reach at 12000 meters of altitude and certainly besides the F-16`s inlet is of D shape and the Su-24 is of rectangular shape, they are not very different from each other creating show waves to disaccelerate the air flow to subsonic speeds.
Besides military turbofans are low by pass ratio engines not very different from turbojets after all
New record, not a single sentence correct, when it comes to performance claims and related physics.
Follow Schorsch advise simply, for the benefit of all.
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By: MiG-23MLD
- 13th June 2008 at 23:44Permalink- Edited 1st January 1970 at 01:00
New record, not a single sentence correct, when it comes to performance claims and related physics.
Follow Schorsch advise simply, for the benefit of all.
so if you are very knowledgeable why do not you give me all the details relating to the inlet design in specific of the Su-24 inlet and the AL-21 engine with details not suggestions of speculations that would be a very good step from you, bluffing is easy but proven you points beyond speculation and gloating well it is not more than intelectual cowboyism
By: Sens
- 14th June 2008 at 00:32Permalink- Edited 1st January 1970 at 01:00
so if you are very knowledgeable why do nou you give me all the details relating to the inlet design in specific of the Su-24 inlet and the AL-21 engine with details not suggestions of speculations that would be a very good step from you, bluffing is easy but proven you points beyond specualtion and gloating well it is not more than intelectual cowboyism
It does not make sense to do so.
For the benefit of the others,
The present jet-engines are in need of subsonic air (Mach 0,4 till Mach 0,7) to create thrust. No severe problem, when subsonic, but critical, when it has to be slow down from faster or supersonic air in the inlet. You need both at the same time, slower and still smooth air for your engine, no distorsion f.e.! There are many ways to achieve that, when it comes to supersonic inlets. For supersonic flight, the inlet-design is more important for thrust, than the engine itself.
At subsonic the inlet gives 12% thrust (netto), the engine 82% and outlet 6%. At high supersonic the inlet gives 63% thrust (netto), the engine a mere 8% and the outlet 29%.
The secret of the F-111 to reach up to Mach 2,5, despite "lower" installed thrust compared to the Su-24 is related to that. Not of practical value in military missions, but an excellent example, what can be achieved by an effective propulsion system and related performances.
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By: MiG-23MLD
- 14th June 2008 at 04:37Permalink- Edited 1st January 1970 at 01:00
It does not make sense to do so.
For the benefit of the others,
The present jet-engines are in need of subsonic air (Mach 0,4 till Mach 0,7) to create thrust. No severe problem, when subsonic, but critical, when it has to be slow down from faster or supersonic air in the inlet. You need both at the same time, slower and still smooth air for your engine, no distorsion f.e.! There are many ways to achieve that, when it comes to supersonic inlets. For supersonic flight, the inlet-design is more important for thrust, than the engine itself.
At subsonic the inlet gives 12% thrust (netto), the engine 82% and outlet 6%. At high supersonic the inlet gives 63% thrust (netto), the engine a mere 8% and the outlet 29%.
The secret of the F-111 to reach up to Mach 2,5, despite "lower" installed thrust compared to the Su-24 is related to that. Not of practical value in military missions, but an excellent example, what can be achieved by an effective propulsion system and related performances.
I see you were very specific you have given so specific facts about the inlet of the Su-24 such as graphs, charts and accurate data about the inlet performance in several flight envelopes
yea very specific, Sens please do not try to cheat me, the Su-24 and F-111 both were designed with a Max speed of Mach 2.4 speed, the Su-24 had a multishock vg ramp in a racked and angled inlet nacelle of rectangular cross section ala MiG-23 or Tu-22M that makes an oblique shock wave.
The inlet up to what i understand lost its multishock VG ramp and only left a ramp that still has the ability of making an oblique shockwave to disaccelerate the airflow to subsonic speed but lacks a multishock VG ramp to keep the shockwave ahead of the inlet lip and out of the inlet duct at higher supersonic speeds. in few words it still can make a shockwave but its design is not as effective to keep the shockwave ahead of the inlet lip as one with a VG ramp such as the early Su-24s.
the VG ramp allows a wider range of speeds since it can create several shockwaves and reduce the air flow from higher supersonic speeds to subsonic speeds at different speeds.
the F-16 has a similar inlet and the F-18 too, they still have a ramp but not a VG ramp to generate oblique shockwaves.
Up to what degree the ramp slows down the air flow for a proper air flow to feed the engine well i do not know and since you do not present me with schematics of the operation of the Su-24`s inlet at Mach 2 without a ramp well i do not know what to think.
Sukhoi says they max operational speed is 1.6, the Ukranian air force says Mach 2 and the f-16 has also a relatively small ramp ahead of the lower lip on the straight part of the D shape inlet.http://www.air-and-space.com/20051021%20AFFTC%20Museum.htm
The F-111 has a different inlet it has a Mirage III or SR-71 style inlet with a conical spike fore and aft within the engine nacelle, to keep the supersonic shock wave just in front of the inlet however depending on the F-111 variant some variants exhibit also a vertical ramp with a semi circular conical spike, the Su-24 had a multishock vg ramp in a racked and angled inlet nacelle of rectangular cross section ala MiG-23, Tu-22M or Su-15 that makes an oblique shock wave.
This approach simplified the construction of the intakes and permitted the use of variable ramps to control the airflow into the engine.
By: Sens
- 14th June 2008 at 11:40Permalink- Edited 1st January 1970 at 01:00
I see you were very specific you have given so specific facts about the inlet of the Su-24 such as graphs, charts and accurate data about the inlet performance in several flight envelopes
yea very specific, Sens please do not try to cheat me, the Su-24 and F-111 both were designed with a Max speed of Mach 2.4 speed, the Su-24 had a multishock vg ramp in a racked and angled inlet nacelle of rectangular cross section ala MiG-23 or F-4 Phantom that makes an oblique shock wave.
The inlet up to what i understand lost its multishock VG ramp and only left a ramp that still has the ability of making an oblique shockwave to disaccelerate the airflow to subsonic speed but lacks a multishock ramp VG ramp to keep the shockwave ahead of the inlet lip and out of the inlet duct at higher supersonic speeds. in few words it still can make a shockwave but its design is not as effective to keep the shockwave ahead of the inlet lip as one with a VG ramp such as the early Su-24s.
the VG ramp allows a wider range of speeds since it can create several shockwaves and reduce the air flow from higher supersonic speeds to subsonic speeds at different speeds.
the F-16 has a similar inlet and the F-18 too, they still have a ramp but not a VG ramp to generate oblique shockwaves.
Up to what degree the ramp slows down the air flow for a proper air flow to feed the engine well i do not know and since you do not present me with schematics of the operation of the Su-24`s inlet at Mach 2 without a ramp well i do not know what to think.
Sukhoi says they max operational speed is 1.6, the Ukranian air force says Mach 2 and the f-16 has also a relatively small ramp ahead of the lower lip on the straight part of the D shape inlet.http://www.air-and-space.com/20051021%20AFFTC%20Museum.htm
The F-111 has a different inlet it has a Mirage III or SR-71 style inlet with a conical spike fore and aft within the engine nacelle, to keep the supersonic shock wave just in front of the inlet however depending on the F-111 variant some variants exhibit also a vertical ramp with a semi circular conical spike, the Su-24 had a multishock vg ramp in a racked and angled inlet nacelle of rectangular cross section ala MiG-23 or F-4 Phantom that makes an oblique shock wave.
This approach simplified the construction of the intakes and permitted the use of variable ramps to control the airflow into the engine.
To read something and to understand something are two different worlds for someone. Whatever I do post of details, such a person is unable or at best unwilling to understand.
For the benefit of the others from the official website of Sukhoi about the Su-24MK:
Maximum flight speed at sea level (without external ordnance and stores), km/h 1,315
Max Mach (without external ordnance and stores) 1.35
Airspeed for Mach 1 at seal level in standard conditions (15°C) is 661 kt or
1224 km/h. Max clean for the Su-24MK at sea level is 1315 km/h or Mach 1,07. The highest nominal speed of Mach 1,35 (clean!) is reached at height.
The speed of Sound is 573 kt at 36090 feet or 1061 km/h at 11000 m (Tropopause) Max Mach number clean for the Su-24MK is Mach 1,35 or 1432 km/h.
Below the link to verify my data: http://www.sukhoi.org/eng/planes/military/su24mk/lth/
With some weapons-load the Su-24MK is in the subsonic or lower transsonic speed-range at all. So that is no setback, when the optimum attack-dash is ~600 kt and cruise/march below 500 kt. We keep in mind, that range/endurance is a severe limiting factor for a striker at low level, at least when it has to go with Tj like the Su-24MK. So the cold logic of Sukhoi is correct, when some fanboys got upset about that for funny reasons. It is their problem to deal with outdated Cold War claims. They do not realize, that the F-111 did fly similar missions at similar speeds too. The main difference is, that the Tf does allow longer range/endurance from every kg/l of fuel carried from the start.
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By: MiG-23MLD
- 14th June 2008 at 21:27Permalink- Edited 1st January 1970 at 01:00
To read something and to understand something are two different worlds for someone. Whatever I do post of details, such a person is unable or at best unwilling to understand.
For the benefit of the others from the official website of Sukhoi about the Su-24MK:
Maximum flight speed at sea level (without external ordnance and stores), km/h 1,315
Max Mach (without external ordnance and stores) 1.35
Airspeed for Mach 1 at seal level in standard conditions (15°C) is 661 kt or
1224 km/h. Max clean for the Su-24MK at sea level is 1315 km/h or Mach 1,07. The highest nominal speed of Mach 1,35 (clean!) is reached at height.
The speed of Sound is 573 kt at 36090 feet or 1061 km/h at 11000 m (Tropopause) Max Mach number clean for the Su-24MK is Mach 1,35 or 1432 km/h.
Below the link to verify my data: http://www.sukhoi.org/eng/planes/military/su24mk/lth/
With some weapons-load the Su-24MK is in the subsonic or lower transsonic speed-range at all. So that is no setback, when the optimum attack-dash is ~600 kt and cruise/march below 500 kt. We keep in mind, that range/endurance is a severe limiting factor for a striker at low level, at least when it has to go with Tj like the Su-24MK. So the cold logic of Sukhoi is correct, when some fanboys got upset about that for funny reasons. It is their problem to deal with outdated Cold War claims. They do not realize, that the F-111 did fly similar missions at similar speeds too. The main difference is, that the Tf does allow longer range/endurance from every kg/l of fuel carried from the start.
Yeah sukhoi claims a mach speed of 1400km/h that is correct, it is around mach 1.35 is not Mach 1.6 that was my mistake, however the Ukranian air force claims two different speeds, one is Mach 1.35 and the other is 2240km/h why the Ukranian air force claims two speeds? are they fan boys? we can call fan boys ourselves because you have never been a Su-24 technician or pilot have you?
Also the Ukrainian air force claims two different ranges one is 2080km and the other 3800km why they have those distances?
Possible explanation a mistake a typo or another possibility different conditions and different limits, the MiG-23 can each Mach 2.5 however the operational speed is mach 2,35.
By: Sens
- 15th June 2008 at 00:01Permalink- Edited 1st January 1970 at 01:00
Yeah sukhoi claims a mach speed of 1400km/h that is correct, it is around mach 1.35 is not Mach 1.6 that was my mistake, however the Ukranian air force claims two different speeds, one is Mach 1.35 and the other is 2240km/h why the Ukranian air force claims two speeds? are they fan boys? we can call fan boys ourselves because you have never been a Su-24 technician or pilot have you?
Also the Ukrainian air force claims two different ranges one is 2080km and the other 3800km why they have those distances?
Possible explanation a mistake a typo or another possibility different conditions and different limits, the MiG-23 can each Mach 2.5 however the operational speed is mach 2,35.
Nothing wrong with 2240 km/h or Mach 2,1 at height with a regulated inlet-system, what was at hand at first. Later it was locked, because the gains from a regulated inlet are limited at low or medium heights.
The websites from the Ukrainian air force were not written by Su-24 technicians or Su-24 pilots.
You are a fan boy for sure, as your blind believe in websites or books do show. I am neither a technician nor a crew member of a Su-24, as all of us here. But I used the opportunities offered to me, to visit the cockpits of both, the F-111 and the Su-24 and question the crew-members and technicians about that. Not all of my questions were answered, but several ones. Security considerations aside, even such persons are not informed about all details of their aircraft or had ever the opportunity to fly it to the limits.
When you do note two very different range claims by the Ukrainian, it is your duty to verify that by asking other reliable sources about that. When unable to do so, you better do not post that nonsense. Not our work to relieve you from that task. Your guessing with the different MiG-23 has nothing to do with the Su-24, just to distract, that you are unable or unwilling to stick to facts, you do not like as your "however" did show.
As long as you stay with pictures, you are excellent, but that is just one side from the same coin.
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By: MiG-23MLD
- 15th June 2008 at 16:34Permalink- Edited 1st January 1970 at 01:00
Nothing wrong with 2240 km/h or Mach 2,1 at height with a regulated inlet-system, what was at hand at first. Later it was locked, because the gains from a regulated inlet are limited at low or medium heights.
The websites from the Ukrainian air force were not written by Su-24 technicians or Su-24 pilots.
You are a fan boy for sure, as your blind believe in websites or books do show. I am neither a technician nor a crew member of a Su-24, as all of us here. But I used the opportunities offered to me, to visit the cockpits of both, the F-111 and the Su-24 and question the crew-members and technicians about that. Not all of my questions were answered, but several ones. Security considerations aside, even such persons are not informed about all details of their aircraft or had ever the opportunity to fly it to the limits.
When you do note two very different range claims by the Ukrainian, it is your duty to verify that by asking other reliable sources about that. When unable to do so, you better do not post that nonsense. Not our work to relieve you from that task. Your guessing with the different MiG-23 has nothing to do with the Su-24, just to distract, that you are unable or unwilling to stick to facts, you do not like as your "however" did show.
As long as you stay with pictures, you are excellent, but that is just one side from the same coin.
Sens
The Su-24 information of the Sukhoi webpage has something that is an obvious mistake
Number and type of engines 2 x AL-21FZA
Thrust:
- in afterburner, kgf 111,200
- at full power, kgf 11,200
compare the what it is written for the Al-31 in the Saturn webpage the say 12500kgf and that is a more powerful engine than the AL-21
http://www.sukhoi.org/eng/planes/military/su24mk/lth/
This proves you even Sukhoi makes typos or mistakes, by the way without having a Su-24 manual is difficult to sift all the contradictory information and data from the Ukranian air force an Sukhoi.
also the range posted by the Ukranian air forces (armed forces to be specific) is 3800km The F-16 can reach Mach 2 at 12000 meters and has a fixed inlet why the Sukhoi Su-24 won`t be able to do it? in few words is possible sukhoi`s information is the best however the Ukranian air force is a reliable source since it is a user and maker since some elements were also built in Ukraine
By: Sens
- 15th June 2008 at 17:57Permalink- Edited 1st January 1970 at 01:00
Sens
The Su-24 information of the Sukhoi webpage has something that is an obvious mistake
Number and type of engines 2 x AL-21FZA
Thrust:
- in afterburner, kgf 111,200
- at full power, kgf 11,200
http://www.sukhoi.org/eng/planes/military/su24mk/lth/
This proves you even Sukhoi makes typos or mistakes, by the way without having a Su-24 manual is difficult to sift all the contradictory information and data from the Ukranian air force an Sukhoi.
also the range posted by the Ukranian air forces (armed forces to be specific) is 3800km The F-16 can reach Mach 2 at 12000 meters and has a fixed inlet why the Sukhoi Su-24 won`t be able to do it? in few words is possible sukhoi`s information is the best however the Ukranian air force is a reliable source since it is a user and maker since some elements were also built in Ukraine
Because both did field different inlet-systems.
Despite unregulated the special compromise form of the inlet of the F-16 does allow speeds up to Mach 1,6 , without too much thrust losses from that. The idea about that was, that air-combat may start at over Mach 1 sometimes, but it is down to subsonic, when the related fighters had to maneuver. Here the propulsion system has to offer the highest thrust to cope with the related forces (remember G-forces!).
Above Mach 1,2 the losses from the inlet-system of the F-16 are noticeable in that that way, that a Mirage 2000 with its regulated system f.e. has a higher thrust above Mach 1,2 despite the higher installed thrust in the F-16. Just the very high installed engine thrust and little drag did allow a clean F-16 to hit Mach 2 briefly under optimum conditions, despite the inlet system was clogged before. But we keep in mind, that behind Mach 1,6 there is no longer something like acceleration for the F-16, just some kind of momentum as your car hill down.
For that findings you are not in need to ask a manual about that.
A second thought does show, that the F-16 and its propulsion system is at best at low to medium level and its inlet-system pose no restriction, when it comes to speed. To reach Mach 2+ every fighter as to go high, below that even regulated ones have to face speed limitations through air-pressure.
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By: MiG-23MLD
- 16th June 2008 at 01:49Permalink- Edited 1st January 1970 at 01:00
Because both did field different inlet-systems.
Despite unregulated the special compromise form of the inlet of the F-16 does allow speeds up to Mach 1,6 , without too much thrust losses from that. The idea about that was, that air-combat may start at over Mach 1 sometimes, but it is down to subsonic, when the related fighters had to maneuver. Here the propulsion system has to offer the highest thrust to cope with the related forces (remember G-forces!).
Above Mach 1,2 the losses from the inlet-system of the F-16 are noticeable in that that way, that a Mirage 2000 with its regulated system f.e. has a higher thrust above Mach 1,2 despite the higher installed thrust in the F-16. Just the very high installed engine thrust and little drag did allow a clean F-16 to hit Mach 2 briefly under optimum conditions, despite the inlet system was clogged before. But we keep in mind, that behind Mach 1,6 there is no longer something like acceleration for the F-16, just some kind of momentum as your car hill down.
For that findings you are not in need to ask a manual about that.
A second thought does show, that the F-16 and its propulsion system is at best at low to medium level and its inlet-system pose no restriction, when it comes to speed. To reach Mach 2+ every fighter as to go high, below that even regulated ones have to face speed limitations through air-pressure.
Up to what i know aircraft not only use the inlet ramp as a way of slowing down the supersonic flow to subsonic speeds they also use the nacelle inlet duct.
Convergent Divergent Diffuser
The diagram to the left shows a simple convergent divergent diffuser. This simple design works because of the fact that supersonic flow will slow down as it enters a constricted area. You will note that this is the opposite response to subsonic flow, which tended to accelerate through a constriction ( In a Venturi Subsonic flow accelerates due to the pressure waves it generates as the the air particles are pushed together. As we know, the air attempts to maintain a constant density and as a result a pressure wave is set up which causes the air to accelerate through the constriction.)
However, at supersonic speed pressure waves can not move out ahead of the air and cause it to accelerate. Therefore the air piles up, becomes more dense, and slows down. This is still all in accordance with Bernoulli's equation which tells us that if the static pressure increases and the density increases, then the velocity must decrease in order to keep the total energy constant. (Generally this tendency of supersonic airflow is more intuitive than subsonic airflow to most people.) http://selair.selkirk.bc.ca/aerodynamics1/High-Speed/Page7.html
In my opinion the F-16 has an inlet ramp and inlet duct that allow the F-16 to slow the supersonic flow with oblique shockwaves and compresibility that allow speeds of Mach 2, i do not know if the same applies for the Su-24 if it really does it
By: Schorsch
- 16th June 2008 at 08:42Permalink- Edited 1st January 1970 at 01:00
Up to what i know aircraft not only use the inlet ramp as a way of slowing down the supersonic flow to subsonic speeds they also use the nacelle inlet duct.
The trick with variable geometry intakes is the control of the shockwaves. An intake that works best at Mach 1.3 may encounter severe difficulties at higher Mach numbers. All aircraft that started with variable geometry intakes and later got those fixed lost their Mach 2 capability, so for example the Tornado, the F-14 and the Starfighter, all with similar or more installed static thrust. The Tornado hardly makes it over M1.3 with the inlets fixed.
By: Schorsch
- 16th June 2008 at 11:10Permalink- Edited 1st January 1970 at 01:00
I plugged some available data into Excel and did some calculations using basic aircraft design methods. I backed it up with data from the MiG-23 (about different glide ratios at various wing sweeps and Mach numbers).
The aircraft used here is an F-111F. I considered reserves, drag of external loads (which is always a guesstimate work of course).
Mission profile is:
Warm-Up, Taxi, Take-Off
Climb with constant IAS to FL300, wings forward
Cruise with constant Mach0.85 at FL300, wings middle
Descent with cosntant IAS to 500ft, wings middle
Fly 70nm at 500ft at full military power, assumed M0.85
Time over target: 2.5min with maximum thrust at 500ft
Egress 30nm with Mach 0.85 at 500ft
Climb to FL350 with constant IAS, wings middle
Cruise at FL350 with Mach 0.8, wings middle
Descent with constant IAS 290, wings forward
Land, Taxi, Shut Down
Results:
[ATTACH]162958[/ATTACH]
Interesting: The low-level ride and time at target consumes about 30% of the total fuel. If one cancels this mission segment (for medium altitude bombing), the radius increases significantly. Lots of tricks can be done changing the cruise in&out Mach numbers.
Attachments
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By: MiG-23MLD
- 16th June 2008 at 16:00Permalink- Edited 1st January 1970 at 01:00
The trick with variable geometry intakes is the control of the shockwaves. An intake that works best at Mach 1.3 may encounter severe difficulties at higher Mach numbers. All aircraft that started with variable geometry intakes and later got those fixed lost their Mach 2 capability, so for example the Tornado, the F-14 and the Starfighter, all with similar or more installed static thrust. The Tornado hardly makes it over M1.3 with the inlets fixed.
I am inclined to think the Su-24 has a max speed of Mach 1.35 since the vast majority of sources have that speed quoted as the max speed.
in fact i think most likely it is the max speed and i am 99% sure the speed is Mach 1.35 however the 1% i am not sure i think it is possible the speed is around 2100km/h and think there is a small probability the Ukranian air force meant the Su-24 can fly that speed and the reason is as you said it might encounter problems we do not know really if the inlet will not work well or simply sukhoi recommends that speed to increase the operational life of the Su-24.
The Range is something that still baffles me because i think it is a fact it wil fly 2775km with two external fuel tanks.
If it flies 3800km well i do not know if it is true or not but i do not think is not possible.
By: franc
- 16th June 2008 at 16:46Permalink- Edited 1st January 1970 at 01:00
The Wiki has already given the most reasonable answer. The VG inlet version of Su-24 Fencer A has top speed above 2 M but the fix inlet version of Su-24 get the lower top speed down to 1.6M. Such decrease also appeared on some other aircraft. The 1.3M is an unreliabe data for depreciative purpose.
By: Sens
- 16th June 2008 at 17:38Permalink- Edited 1st January 1970 at 01:00
The Wiki has already given the most reasonable answer. The VG inlet version of Su-24 Fencer A has top speed above 2 M but the fix inlet version of Su-24 get the lower top speed down to 1.6M. Such decrease also appeared on some other aircraft. The 1.3M is an unreliabe data for depreciative purpose.
That "unreliable" data is given by Sukhoi and in line with restrictions from fix inlet.
The Mirage 2000N with fixed inlet is max Mach 1,4 f.e..
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By: MiG-23MLD
- 16th June 2008 at 17:47Permalink- Edited 1st January 1970 at 01:00
The Wiki has already given the most reasonable answer. The VG inlet version of Su-24 Fencer A has top speed above 2 M but the fix inlet version of Su-24 get the lower top speed down to 1.6M. Such decrease also appeared on some other aircraft. The 1.3M is an unreliabe data for depreciative purpose.
I think probably Sukhoi is only quoting the max speed at sea level see
Максимальная скорость, км/ч
на высоте 1700
на уровне моря 1400
airwar ru quotes a Max speed of Mach 1.6 speed at altitude and 1.4 at sea level
same is aviaport ЛЕТНЫЕ ДАННЫЕ (Су 24М). Максимальная скорость 1700 км/ч, максимальная скорость у земли 1400 км/ч, практический потолок 11 000 м
however the belarussian air force has different data too Тактико-технические данные:
Экипаж, чел. - 2
Число двигателей - 2
Тип двигателей - 2хАЛ-21
Максимальная взлётная масса, кг - 39700 Max weight 39700kg
Максимальная скорость полёта, км/час - 1320 (max speed 1320km\h)
Практический потолок,м - 11500
Дальность полёта, км - 2500
Максимальная бомбовая нагрузка,кг - 7500
Габаритные размеры: длина - 24,5м, высота - 6,2м, размах крыла- 17,7м. http://mod.mil.by/s31su24.htmlhttp://mod.mil.by/s31su24.html
It is funny because it does not concord with Sukhoi on matters of weight
however other webpages quotes different speed
Максимальная скорость, км/ч - 2320 Max speed 2320 km/h
Максимальная скорость у земли, км/ч - 1400 Max speed a sea level 1400km/h
Практический потолок, м - 17500
Максимальная дальность полета, км - 1300
Перегоночная дальность полета, км - 4270
Разбег, м - 900
Пробег,м - 850
however the belarussian air froces has different data too Тактико-технические данные:
Экипаж, чел. - 2
Число двигателей - 2
Тип двигателей - 2хАЛ-21
Максимальная взлётная масса, кг - 39700
Максимальная скорость полёта, км/час - 1320
Практический потолок,м - 11500
Дальность полёта, км - 2500
Максимальная бомбовая нагрузка,кг - 7500
Габаритные размеры: длина - 24,5м, высота - 6,2м, размах крыла- 17,7м. http://mod.mil.by/s31su24.htmlhttp://mod.mil.by/s31su24.html
Dude most of us can't read klingon or whatever that writing is.
Posts: 11,742
By: Sens - 13th June 2008 at 14:22 Permalink - Edited 1st January 1970 at 01:00
Are someone unable to read data in a correct way.
From producer:
Takeoff weight:
- normal, kg 38,040
- maximum, kg 43,755
Normal ordnance load, kg 3,000
Maximum ordnance load, kg 8,000
The first value is with 3 tons normal weapons load.
The second value is with 8 tons weapons load.
Posts: 3,010
By: MiG-23MLD - 13th June 2008 at 22:53 Permalink - Edited 1st January 1970 at 01:00
Schorsch
Since the moment i said the inlet is the main factor to judge if the Su-24 can or can not reach Mach 2 i know even the basics to say the AL-21 needs pressure recovery, since the engine demands the less drag possible and a specific flow of air.
The F-16 as the Su-24 won`t fly Mach 2 at low altitude, so certainly they will fly at mach 2 at similar conditions and not at low altitude, the inlet design and the engine in the F-16 are flexible enough to accept the flow conditions in the inlet to work properly, the F-16 does not need a VG ramp inlet to work well, the Ukranian air force webpage and some other sources claim a speed of Mach 2, the same speed the F-16 can reach at 12000 meters of altitude and certainly besides the F-16`s inlet is of D shape and the Su-24 is of rectangular shape, they are not very different from each other creating shock waves to disaccelerate the air flow to subsonic speeds.
Besides military turbofans are low by pass ratio engines not very different from turbojets after all
Posts: 11,742
By: Sens - 13th June 2008 at 23:38 Permalink - Edited 1st January 1970 at 01:00
New record, not a single sentence correct, when it comes to performance claims and related physics.
Follow Schorsch advise simply, for the benefit of all.
Posts: 3,010
By: MiG-23MLD - 13th June 2008 at 23:44 Permalink - Edited 1st January 1970 at 01:00
so if you are very knowledgeable why do not you give me all the details relating to the inlet design in specific of the Su-24 inlet and the AL-21 engine with details not suggestions of speculations that would be a very good step from you, bluffing is easy but proven you points beyond speculation and gloating well it is not more than intelectual cowboyism
Posts: 11,742
By: Sens - 14th June 2008 at 00:32 Permalink - Edited 1st January 1970 at 01:00
It does not make sense to do so.
For the benefit of the others,
The present jet-engines are in need of subsonic air (Mach 0,4 till Mach 0,7) to create thrust. No severe problem, when subsonic, but critical, when it has to be slow down from faster or supersonic air in the inlet. You need both at the same time, slower and still smooth air for your engine, no distorsion f.e.! There are many ways to achieve that, when it comes to supersonic inlets. For supersonic flight, the inlet-design is more important for thrust, than the engine itself.
At subsonic the inlet gives 12% thrust (netto), the engine 82% and outlet 6%. At high supersonic the inlet gives 63% thrust (netto), the engine a mere 8% and the outlet 29%.
The secret of the F-111 to reach up to Mach 2,5, despite "lower" installed thrust compared to the Su-24 is related to that. Not of practical value in military missions, but an excellent example, what can be achieved by an effective propulsion system and related performances.
Posts: 3,010
By: MiG-23MLD - 14th June 2008 at 04:37 Permalink - Edited 1st January 1970 at 01:00
I see you were very specific you have given so specific facts about the inlet of the Su-24 such as graphs, charts and accurate data about the inlet performance in several flight envelopes
yea very specific, Sens please do not try to cheat me, the Su-24 and F-111 both were designed with a Max speed of Mach 2.4 speed, the Su-24 had a multishock vg ramp in a racked and angled inlet nacelle of rectangular cross section ala MiG-23 or Tu-22M that makes an oblique shock wave.
The inlet up to what i understand lost its multishock VG ramp and only left a ramp that still has the ability of making an oblique shockwave to disaccelerate the airflow to subsonic speed but lacks a multishock VG ramp to keep the shockwave ahead of the inlet lip and out of the inlet duct at higher supersonic speeds. in few words it still can make a shockwave but its design is not as effective to keep the shockwave ahead of the inlet lip as one with a VG ramp such as the early Su-24s.
the VG ramp allows a wider range of speeds since it can create several shockwaves and reduce the air flow from higher supersonic speeds to subsonic speeds at different speeds.
the F-16 has a similar inlet and the F-18 too, they still have a ramp but not a VG ramp to generate oblique shockwaves.
Up to what degree the ramp slows down the air flow for a proper air flow to feed the engine well i do not know and since you do not present me with schematics of the operation of the Su-24`s inlet at Mach 2 without a ramp well i do not know what to think.
Sukhoi says they max operational speed is 1.6, the Ukranian air force says Mach 2 and the f-16 has also a relatively small ramp ahead of the lower lip on the straight part of the D shape inlet.http://www.air-and-space.com/20051021%20AFFTC%20Museum.htm
The F-111 has a different inlet it has a Mirage III or SR-71 style inlet with a conical spike fore and aft within the engine nacelle, to keep the supersonic shock wave just in front of the inlet however depending on the F-111 variant some variants exhibit also a vertical ramp with a semi circular conical spike, the Su-24 had a multishock vg ramp in a racked and angled inlet nacelle of rectangular cross section ala MiG-23, Tu-22M or Su-15 that makes an oblique shock wave.
This approach simplified the construction of the intakes and permitted the use of variable ramps to control the airflow into the engine.
Posts: 11,742
By: Sens - 14th June 2008 at 11:40 Permalink - Edited 1st January 1970 at 01:00
To read something and to understand something are two different worlds for someone. Whatever I do post of details, such a person is unable or at best unwilling to understand.
For the benefit of the others from the official website of Sukhoi about the Su-24MK:
Maximum flight speed at sea level (without external ordnance and stores), km/h 1,315
Max Mach (without external ordnance and stores) 1.35
Airspeed for Mach 1 at seal level in standard conditions (15°C) is 661 kt or
1224 km/h. Max clean for the Su-24MK at sea level is 1315 km/h or Mach 1,07. The highest nominal speed of Mach 1,35 (clean!) is reached at height.
The speed of Sound is 573 kt at 36090 feet or 1061 km/h at 11000 m (Tropopause)
Max Mach number clean for the Su-24MK is Mach 1,35 or 1432 km/h.
Below the link to verify my data:
http://www.sukhoi.org/eng/planes/military/su24mk/lth/
With some weapons-load the Su-24MK is in the subsonic or lower transsonic speed-range at all. So that is no setback, when the optimum attack-dash is ~600 kt and cruise/march below 500 kt. We keep in mind, that range/endurance is a severe limiting factor for a striker at low level, at least when it has to go with Tj like the Su-24MK. So the cold logic of Sukhoi is correct, when some fanboys got upset about that for funny reasons. It is their problem to deal with outdated Cold War claims. They do not realize, that the F-111 did fly similar missions at similar speeds too. The main difference is, that the Tf does allow longer range/endurance from every kg/l of fuel carried from the start.
Posts: 3,010
By: MiG-23MLD - 14th June 2008 at 21:27 Permalink - Edited 1st January 1970 at 01:00
Yeah sukhoi claims a mach speed of 1400km/h that is correct, it is around mach 1.35 is not Mach 1.6 that was my mistake, however the Ukranian air force claims two different speeds, one is Mach 1.35 and the other is 2240km/h why the Ukranian air force claims two speeds? are they fan boys? we can call fan boys ourselves because you have never been a Su-24 technician or pilot have you?
Also the Ukrainian air force claims two different ranges one is 2080km and the other 3800km why they have those distances?
Possible explanation a mistake a typo or another possibility different conditions and different limits, the MiG-23 can each Mach 2.5 however the operational speed is mach 2,35.
Posts: 11,742
By: Sens - 15th June 2008 at 00:01 Permalink - Edited 1st January 1970 at 01:00
Nothing wrong with 2240 km/h or Mach 2,1 at height with a regulated inlet-system, what was at hand at first. Later it was locked, because the gains from a regulated inlet are limited at low or medium heights.
The websites from the Ukrainian air force were not written by Su-24 technicians or Su-24 pilots.
You are a fan boy for sure, as your blind believe in websites or books do show. I am neither a technician nor a crew member of a Su-24, as all of us here. But I used the opportunities offered to me, to visit the cockpits of both, the F-111 and the Su-24 and question the crew-members and technicians about that. Not all of my questions were answered, but several ones. Security considerations aside, even such persons are not informed about all details of their aircraft or had ever the opportunity to fly it to the limits.
When you do note two very different range claims by the Ukrainian, it is your duty to verify that by asking other reliable sources about that. When unable to do so, you better do not post that nonsense. Not our work to relieve you from that task. Your guessing with the different MiG-23 has nothing to do with the Su-24, just to distract, that you are unable or unwilling to stick to facts, you do not like as your "however" did show.
As long as you stay with pictures, you are excellent, but that is just one side from the same coin.
Posts: 3,010
By: MiG-23MLD - 15th June 2008 at 16:34 Permalink - Edited 1st January 1970 at 01:00
Sens
The Su-24 information of the Sukhoi webpage has something that is an obvious mistake
Number and type of engines 2 x AL-21FZA
Thrust:
- in afterburner, kgf 111,200
- at full power, kgf 11,200
compare the what it is written for the Al-31 in the Saturn webpage the say 12500kgf and that is a more powerful engine than the AL-21
Технические характеристики АЛ-31Ф/ФН:
http://www.npo-saturn.ru/!new/index.php?pid=53
http://www.sukhoi.org/eng/planes/military/su24mk/lth/
This proves you even Sukhoi makes typos or mistakes, by the way without having a Su-24 manual is difficult to sift all the contradictory information and data from the Ukranian air force an Sukhoi.
also the range posted by the Ukranian air forces (armed forces to be specific) is 3800km
The F-16 can reach Mach 2 at 12000 meters and has a fixed inlet why the Sukhoi Su-24 won`t be able to do it? in few words is possible sukhoi`s information is the best however the Ukranian air force is a reliable source since it is a user and maker since some elements were also built in Ukraine
Posts: 11,742
By: Sens - 15th June 2008 at 17:57 Permalink - Edited 1st January 1970 at 01:00
Because both did field different inlet-systems.
Despite unregulated the special compromise form of the inlet of the F-16 does allow speeds up to Mach 1,6 , without too much thrust losses from that. The idea about that was, that air-combat may start at over Mach 1 sometimes, but it is down to subsonic, when the related fighters had to maneuver. Here the propulsion system has to offer the highest thrust to cope with the related forces (remember G-forces!).
Above Mach 1,2 the losses from the inlet-system of the F-16 are noticeable in that that way, that a Mirage 2000 with its regulated system f.e. has a higher thrust above Mach 1,2 despite the higher installed thrust in the F-16. Just the very high installed engine thrust and little drag did allow a clean F-16 to hit Mach 2 briefly under optimum conditions, despite the inlet system was clogged before. But we keep in mind, that behind Mach 1,6 there is no longer something like acceleration for the F-16, just some kind of momentum as your car hill down.
For that findings you are not in need to ask a manual about that.
A second thought does show, that the F-16 and its propulsion system is at best at low to medium level and its inlet-system pose no restriction, when it comes to speed. To reach Mach 2+ every fighter as to go high, below that even regulated ones have to face speed limitations through air-pressure.
Posts: 3,010
By: MiG-23MLD - 16th June 2008 at 01:49 Permalink - Edited 1st January 1970 at 01:00
Up to what i know aircraft not only use the inlet ramp as a way of slowing down the supersonic flow to subsonic speeds they also use the nacelle inlet duct.
Convergent Divergent Diffuser
The diagram to the left shows a simple convergent divergent diffuser. This simple design works because of the fact that supersonic flow will slow down as it enters a constricted area. You will note that this is the opposite response to subsonic flow, which tended to accelerate through a constriction ( In a Venturi Subsonic flow accelerates due to the pressure waves it generates as the the air particles are pushed together. As we know, the air attempts to maintain a constant density and as a result a pressure wave is set up which causes the air to accelerate through the constriction.)
However, at supersonic speed pressure waves can not move out ahead of the air and cause it to accelerate. Therefore the air piles up, becomes more dense, and slows down. This is still all in accordance with Bernoulli's equation which tells us that if the static pressure increases and the density increases, then the velocity must decrease in order to keep the total energy constant. (Generally this tendency of supersonic airflow is more intuitive than subsonic airflow to most people.)
http://selair.selkirk.bc.ca/aerodynamics1/High-Speed/Page7.html
In my opinion the F-16 has an inlet ramp and inlet duct that allow the F-16 to slow the supersonic flow with oblique shockwaves and compresibility that allow speeds of Mach 2, i do not know if the same applies for the Su-24 if it really does it
Posts: 3,718
By: Schorsch - 16th June 2008 at 08:42 Permalink - Edited 1st January 1970 at 01:00
The trick with variable geometry intakes is the control of the shockwaves. An intake that works best at Mach 1.3 may encounter severe difficulties at higher Mach numbers. All aircraft that started with variable geometry intakes and later got those fixed lost their Mach 2 capability, so for example the Tornado, the F-14 and the Starfighter, all with similar or more installed static thrust. The Tornado hardly makes it over M1.3 with the inlets fixed.
Posts: 3,718
By: Schorsch - 16th June 2008 at 11:10 Permalink - Edited 1st January 1970 at 01:00
I plugged some available data into Excel and did some calculations using basic aircraft design methods. I backed it up with data from the MiG-23 (about different glide ratios at various wing sweeps and Mach numbers).
The aircraft used here is an F-111F. I considered reserves, drag of external loads (which is always a guesstimate work of course).
Mission profile is:
Results:
[ATTACH]162958[/ATTACH]
Interesting: The low-level ride and time at target consumes about 30% of the total fuel. If one cancels this mission segment (for medium altitude bombing), the radius increases significantly. Lots of tricks can be done changing the cruise in&out Mach numbers.
Posts: 3,010
By: MiG-23MLD - 16th June 2008 at 16:00 Permalink - Edited 1st January 1970 at 01:00
I am inclined to think the Su-24 has a max speed of Mach 1.35 since the vast majority of sources have that speed quoted as the max speed.
in fact i think most likely it is the max speed and i am 99% sure the speed is Mach 1.35 however the 1% i am not sure i think it is possible the speed is around 2100km/h and think there is a small probability the Ukranian air force meant the Su-24 can fly that speed and the reason is as you said it might encounter problems we do not know really if the inlet will not work well or simply sukhoi recommends that speed to increase the operational life of the Su-24.
The Range is something that still baffles me because i think it is a fact it wil fly 2775km with two external fuel tanks.
If it flies 3800km well i do not know if it is true or not but i do not think is not possible.
Posts: 620
By: franc - 16th June 2008 at 16:46 Permalink - Edited 1st January 1970 at 01:00
The Wiki has already given the most reasonable answer. The VG inlet version of Su-24 Fencer A has top speed above 2 M but the fix inlet version of Su-24 get the lower top speed down to 1.6M. Such decrease also appeared on some other aircraft. The 1.3M is an unreliabe data for depreciative purpose.
Posts: 11,742
By: Sens - 16th June 2008 at 17:38 Permalink - Edited 1st January 1970 at 01:00
That "unreliable" data is given by Sukhoi and in line with restrictions from fix inlet.
The Mirage 2000N with fixed inlet is max Mach 1,4 f.e..
Posts: 3,010
By: MiG-23MLD - 16th June 2008 at 17:47 Permalink - Edited 1st January 1970 at 01:00
I think probably Sukhoi is only quoting the max speed at sea level see
Максимальная скорость, км/ч
на высоте 1700
на уровне моря 1400
airwar ru quotes a Max speed of Mach 1.6 speed at altitude and 1.4 at sea level
same is aviaport ЛЕТНЫЕ ДАННЫЕ (Су 24М). Максимальная скорость 1700 км/ч, максимальная скорость у земли 1400 км/ч, практический потолок 11 000 м
http://www.aviaport.ru/directory/aviation/458.html
however the belarussian air force has different data too
Тактико-технические данные:
Экипаж, чел. - 2
Число двигателей - 2
Тип двигателей - 2хАЛ-21
Максимальная взлётная масса, кг - 39700 Max weight 39700kg
Максимальная скорость полёта, км/час - 1320 (max speed 1320km\h)
Практический потолок,м - 11500
Дальность полёта, км - 2500
Максимальная бомбовая нагрузка,кг - 7500
Габаритные размеры: длина - 24,5м, высота - 6,2м, размах крыла- 17,7м.
http://mod.mil.by/s31su24.htmlhttp://mod.mil.by/s31su24.html
It is funny because it does not concord with Sukhoi on matters of weight
however other webpages quotes different speed
Максимальная скорость, км/ч - 2320 Max speed 2320 km/h
Максимальная скорость у земли, км/ч - 1400 Max speed a sea level 1400km/h
Практический потолок, м - 17500
Максимальная дальность полета, км - 1300
Перегоночная дальность полета, км - 4270
Разбег, м - 900
Пробег,м - 850
http://aviacia.ru/view.php?lang=ru&req=bomber&id=16
Posts: 776
By: Jon James - 16th June 2008 at 17:50 Permalink - Edited 1st January 1970 at 01:00
Dude most of us can't read klingon or whatever that writing is.
Posts: 1,856
By: dionis - 16th June 2008 at 18:03 Permalink - Edited 1st January 1970 at 01:00
Which is why most of you can only pretend to understand anything Russian. :rolleyes: