Some interesting claims about the F-22 on Wikipedia

Unread postPosted: 22 May 2006, 14:07
by FDiron
http://en.wikipedia.org/wiki/F-22

This site makes some very interesting claims about the F-22.

RE: Very informative page on the F-22

Unread postPosted: 22 May 2006, 15:19
by Guysmiley
Wikipedia is an interesting beast. You have to realize that anyone can edit the page. It kind of needs to be taken with a grain of salt (especially if there is no cited source for a piece of information)

Unread postPosted: 22 May 2006, 16:49
by Shonuff
is that statement by paul metz true?

Unread postPosted: 22 May 2006, 17:07
by snypa777
* Maximum speed: >Mach 2.42, 1,600 mph (2,570 km/h) at high altitude
* Cruise speed: >Mach 1.72, 1,140 mph (1,830 km/h) at high altitude
* Range: ferry 2,000 mi (3,200 km)
* Service ceiling: >50,000 ft USAF, 60,000 Boeing (>15,000 m, 18,000 m)
* Rate of climb: ft/min[3] (m/s) Better than F-15 (mentioned later in blurb).
* Wing loading: 96 lb/ft² (470 kg/m²)
* Thrust/weight: 1.3~1.41
* Maximum g-load: 9.5 g

Yep, interesting! We have never seen true top speed or supercruise maximums.
That`s Wikipedia for you! Actually, it is amazing how many web pages quote directly from Wiki`. It is suspected that the F-22 can do better than M 1.7 in supercruise now but no one is saying.... 8)

Who knows if Metz was BS-ing or not. Is Metz pro-F-22 or not? Ok, he flew the thing but does he like it?

Unread postPosted: 22 May 2006, 17:12
by Guysmiley
Didn't see any cited reference to the Metz "quote", so who knows. The official AF page says non-AB cruise of Mach 1.5+, max speed of "Mach 2 class".

Here is an interesting interview with Paul Metz (with no reference to maximum speeds) http://www.ausairpower.net/API-Metz-Interview.html

Unread postPosted: 22 May 2006, 17:41
by snypa777
Think that about ties up any doubts that Metz is an F-22 fan! I hadn`t heard about the guy previously.... :lol:

I don`t like Carlo Kopp usually but he let Metz do all the talking.
I found it interesting that a pilot can still over-G a Viper in the roll. Even with it`s Flight control software. Saying that, the interview is 7 years old...

No such worries with the `22. Carefree handling seems the buzz-phrase for the latest gen` of fighters.

Unread postPosted: 22 May 2006, 22:12
by sferrin
I saw the piece of the Discovery Channel where they were talking to Paul Metz. His exact quote about the speed was "it's fast, I mean it's REALLY fast. The top speed is classified but it'll do sixteen-hundred miles per hour." As for him being an F-22 fan people have asked him which is better the F-22 or the F-23 and he tap dances all around that one :lol: (He was the chief test pilot on both the YF-23 and the F-22A).

Unread postPosted: 23 May 2006, 00:55
by snypa777
sferrin wrote:I saw the piece of the Discovery Channel where they were talking to Paul Metz. His exact quote about the speed was "it's fast, I mean it's REALLY fast. The top speed is classified but it'll do sixteen-hundred miles per hour." As for him being an F-22 fan people have asked him which is better the F-22 or the F-23 and he tap dances all around that one :lol: (He was the chief test pilot on both the YF-23 and the F-22A).



Lol, I think a whole lot of people tap danced around that question!

Unread postPosted: 23 May 2006, 09:42
by Raptor_One
I actually did the math and posted this in a much older thread, but if you calculate the possible Mach numbers that 16000 MPH equates to and discard impossibly high Mach numbers and indicated/calibrated airspeeds at low altitudes, you come out with something aroudn Mach 2.42 around 36-40K. So if he was telling the truth about 1600 MPH, the F-22 can do at least Mach 2.4 or thereabouts at altitude.

Unread postPosted: 23 May 2006, 13:47
by Meathook
I have a nice video if I can get it to post here...never mind, say the file is too big - sorry guys

Unread postPosted: 23 May 2006, 14:07
by toan
The supercurise capability of F-22A has been confirmed by EX-USAF Chief of Staff Gen. John P. Jumper:

http://www.hilltoptimes.com/story.asp?e ... oryid=5353

“Today I flew the Raptor at speeds exceeding Mach 1.7 without afterburners,” General Jumper said. “To be able to go that fast without afterburners means that nobody can get you in their sights or get a lock-on. The aircraft’s impressive stealth capability, combined with its super cruise (capability), will give any adversary a very hard time.” (Courtesy of Air Education and Training Command News Service).

A Japanese military magazine declared that the maximal speed / maximal supercurise speed of Raptor could reach 2.25 Mach+ / 1.82 Mach last year. But I have no idea where its information came from.

As for the empty weight of Raptor, some web-sites of USAF declared it as "40,000 Ibs / 18,000 kg class", while some special report of IDR in 2002/06/01 declared it as "19,489 kg".

http://www.af.mil/factsheets/factsheet.asp?fsID=199

http://usmilitary.about.com/od/afweapons/l/blf22.htm

http://www.globalsecurity.org/military/ ... l31673.pdf

Unread postPosted: 23 May 2006, 14:41
by toan
* Maximum speed: >Mach 2.42, 1,600 mph (2,570 km/h) at high altitude
A: No idea, but I think it should be achieveable by Raptor at a certain range of altitude if you don't care about the possible damage of its stealthy coating.


* Cruise speed: >Mach 1.72, 1,140 mph (1,830 km/h) at high altitude
A: Generally confirmed by EX-USAF Chief of Staff Gen. John P. Jumper.


* Range: ferry 2,000 mi (3,200 km)
A: 2,778 ~ 3,704 km according to different sources of military news / information (with internal fuel only).


* Service ceiling: >50,000 ft USAF, 60,000 Boeing (>15,000 m, 18,000 m)
A: Many military analysts believe its service ceiling could reach 70,000-fts class.

* Wing loading: 96 lb/ft² (470 kg/m²)
A: The wing area of F-22 is 78.3 m2, and 470 x 78.3 = 36,801 kg............


* Maximum sustaineous g-load: 9.5 g
A: This has been confirmed by a Raptor's pilot this year.

Unread postPosted: 23 May 2006, 18:33
by checksixx
Well having worked for Gen. Jumper, I can tell you that he does not BS about anything. They publicly stated 9.5G's about the Raptor at the Langley show this year. Keep in mind thats only limited by what the pilot can take. The F-117 airframe has a max G load of 12G's.

-Check

Unread postPosted: 24 May 2006, 17:14
by Meathook
I would agree, I too know him, he tells it like it is, I always liked that about him (especially when we was the 57th FWW/CC) back at Nellis. - Good, did very well for himself too.

Unread postPosted: 25 May 2006, 01:24
by Obi_Offiah
checksixx wrote:Well having worked for Gen. Jumper, I can tell you that he does not BS about anything. They publicly stated 9.5G's about the Raptor at the Langley show this year. Keep in mind thats only limited by what the pilot can take. The F-117 airframe has a max G load of 12G's.

-Check


I've seen this mentioned alot, about the pilot being the weakest link. Modern G-suits enable pilots to reach 12G but 9G seems to be the design limit even for advanced modern fighters. Do the designers feel that 9G is sufficient, that by increasing aircrafts structural G tolerance above this amount may compromise performance, (added weight)?.

Cheers
Obi

Unread postPosted: 25 May 2006, 03:13
by sferrin
Meathook wrote:I have a nice video if I can get it to post here...never mind, say the file is too big - sorry guys


How big is it? (Like they say "where there's a will there's a way" :) )

Unread postPosted: 25 May 2006, 19:41
by Brad
I attempted to edit the F-22 file to reflect more recent information, such as the empty weight of ~43,000lbs (was going to use USAF official “40,000lb class”), correct the ferry range, T:W, wing loading etc. Either I’m not doing it right or somebody is coming along after me and changing it back. Maybe someone else gets bored as I was and can change it.

There has been some questions regarding the F-22’s range so I did some crude number crunching for the F-22’s range based on the Stevenson’s PPT slides. Now the obvious caveat is the source of information (Riccioni’s ilk) but we’ll go with his numbers for lack of any other references. He gives Specific Range numbers based on a nominal 60,000lb weight at various altitude and mach points. He cites a nominal SR of ~0.04 nm/lb at M1.5, 45,000 feet. He does not show numbers for higher altitudes and his envelope that he has for dry thrust says that the F-22 can’t go above 50K with dry thrust (M1.7+ is reached at ~36K) and to reach FL500 the F-22 has to be at ~M1.5-- I don’t know if this is true or not.

The USAF has said that the F-22 will go 1,724 miles ferry—but doesn’t specify if this is nautical or statute or if this is with internal gas or not:

http://www.f22-raptor.com/technology/data.html

If this is in statute like I suspect, then Stevenson’s SR of 0.76 at M0.9/40,000’ means that is must have at least 19,740lbs -- and that is with absolutely no fuel reserves. He does give a SR of 0.07 at M0.8/30K which is about ~0.005 mi/lb better than at M0.9/30K. I do not think that the USAF’s figure is for internal + external gas as even at 0.76 that’s over 2,600nm so its probably on internal gas only. With that being said it does not look like the ~ 18,400lbs is correct for internal unless the SR is better that what Stevenson’s slides suggest.

Now I know many aren’t too high on Kopp but for the most part his numbers on specs are correct and he’s reporting 20,650lbs internal. This seems to me more realistic as that’s about 2,200lbs more than the F-35A, which would also have similar internal space limitations with deeper bays and a more narrow fuselage profile with smaller overall size. This suggests that a nominal SR on internal gas of about 1,805sm or about 1,570nm. Still not enough for taxi/TO/reserve + 1724 mi but closer and if this profile is at M0.8 at 40K there’s a possibility that the SR is somewhat better making it more realistic. Either way the range is probably better -- either by internal gas or TSFC -- than what Stevenson’s slides suggest.

Interestingly if we consider that AFA article that stated the Raptor’s range with sub + SS of 405 +100nm radius and use Stevenson’s SR numbers that gives us a total fuel burn of about 15,100lbs. At 18,348 that gives a margin of only 3,000lbs, but if it has a 20,650 internal that’s about 5,000lbs for TO/climb/combat or loiter.

I don’t think the AFA scenario is very realistic so I crunched some numbers for a nominal strike/OCA sortie but instead of a specific range I looked at how far could the thing go if it had two tankings and cruised at M1.5 with a SR of 0.04 and 0.045 (A SR of 0.045 is extrapolated for 50,000’). I did this with 18,500 and 20,650lbs. Here is some of the criterion common to both (crudely estimated):

1st Leg (ingress)

Taxi/TO Burn- 1,100lbs
Climb (FL450)- 2,500lbs (100nm)
Reserve- 2,000lbs
Cruise: ?

Penetration Radius (Tank in - fight - Tank out)

Combat- 4,100lbs
Reserve- 2,000lbs
Radius: ?

3rd Leg (egress)

Descent- 1,500lbs (135nm, 3° descent)
Reserve- 3,300lbs
Cruise: ?

In this first two the 2,000lbs give about 18 min for tanking. This may be too tight or not accurate but this is what I went with. The 3,300 lbs of reserve on the last one is about 30 minutes or so of reserve fuel at home plate.


18,400lbs

Ingress leg gives a total distance of 610nm with 510nm at M1.5 and a total time (including 15 minutes for tanking) of 66 minutes with a SR of 0.040. If the SR is 0.045 then the distance goes up to 679 and time to 70 minutes. The penetration leg gives a radius of 245nm and 55 minutes, which again includes 15 minutes of tanking on the way back and 10 minutes of combat or about 35 minutes of loiter (M0.8 at 30K). If we assume SR of 0.045 then the radius goes up to 278 and time to 59 minutes with the other numbers staying the same. Finally on the way back we can go 677nm total in about 58 minutes at 0.04 or to about 751nm and 62 minutes at SR of 0.045. This last leg theoretically shouldn’t be any longer than the first unless there’s a head wind but it at least gives an idea. Admittedly these numbers are pretty bare assed and maybe too tight but are there for illustrative purposes.

20,650lbs

I’ll just simplify:

Ingress:

0.040- 702nm/71 minutes
0.045- 784nm/76 minutes

Penetration:

0.040- 291nm/60 minutes
0.045- 331nm/65 minutes

Egress:

0.040- 769nm/63 minutes
0.045- 855nm/69 minutes

Totals:

18,400lbs

Radius: 1,532nm (0.04)
Time: 3hours, 9 minutes

Radius: 1,709nm (0.045)
Time: 3hours, 11 minutes

Fuel Burn: 47,774lbs

20,650lbs

Radius: 1,762nm (0.04)
Time: 3hours, 15minutes

Radius: 1,970nm (0.045)
Time: 3hours, 30 minutes

Fuel Burn: 54,650lbs

By comparison for the F-15C w/3 bags and a nominal 1,500nm radius (1 tanking assumed)

17,542lbs

Radius: 1,532
Time: 3 hours, 54 minutes.

Fuel Burn: 27,241lbs

Sortie per day (ignoring pilot availability and assuming 1hour in between launches)

F-22A- 5.8
F-15C- 4.9

Thus if one assumes a standard availability of 80% then one squadron of each aircraft should produce in a day:

F-22A- 120
F-15C- 102

If the jet still had the reported 25,000lbs internal then it should be able to go about 2,200nm ~ 2,460nm with the above scenario.

Brad

Unread postPosted: 27 May 2006, 20:53
by Angels225
About the max Altitude of the raptor, I read some dude took an early block viper above 80,000 ft, In fact the link was posted here, but darn it i forgot where it was, Comsidering the greater T/W ratio of the raptor, I reckon it should be able to go a bit further than that.

Unread postPosted: 27 May 2006, 21:22
by fifel144
Has anyone been informed what it does going vertical? :shock: :notworthy:

Unread postPosted: 27 May 2006, 22:03
by snypa777
Angels225 wrote:About the max Altitude of the raptor, I read some dude took an early block viper above 80,000 ft, In fact the link was posted here, but darn it i forgot where it was, Comsidering the greater T/W ratio of the raptor, I reckon it should be able to go a bit further than that.


Hmm, although it may be fun/impressive, is there any real tactical advantage in flying at mega- altitude? Flying at 50,000ft above enemy fighters is`nt going to help you shoot him down....

I think only recon` aircraft would benefit from flying at mega high alt` to get photo coverage. There are PLENTY of SAM systems that can reach higher than most fighters max` altitude... I would also think that flaming out is not a popular circumstance to flirt with as well as popping canopy seals....

I don`t actually doubt the F-22 could fly VERY high. If you can`t see it though, wouldn`t 60,000 ft be quite adequate?

Unread postPosted: 27 May 2006, 23:53
by sferrin
The higher you are the further your missiles will go. 1. they've got more altitude to trade for range, 2. thinner air for less drag, and 3. less backpressure so you get better ISP out of your motor. As far as the fuel load the YF-22's was given as 23,000lbs internal. Granted they slimmed down the F-22A's fuselage somewhat but I'd be surprised if they lost so much volume that they gave up 5000lbs of fuel if they didn't have to.

Unread postPosted: 28 May 2006, 18:09
by snypa777
sferrin wrote:The higher you are the further your missiles will go. 1. they've got more altitude to trade for range, 2. thinner air for less drag, and 3. less backpressure so you get better ISP out of your motor. As far as the fuel load the YF-22's was given as 23,000lbs internal. Granted they slimmed down the F-22A's fuselage somewhat but I'd be surprised if they lost so much volume that they gave up 5000lbs of fuel if they didn't have to.


Cool, I understand the range advantage with higher altitude cruise and weapons. I wonder why ALL fighters don`t cruise at 80,000+ ft though? It isn`t technologically that difficult, except when you include "high speed". In fact, aircraft speed drops at altitude (Standard fighters at their ceiling limits) where there isn`t enough air for engine efficiency. I can see the advantage in getting range for dropping bombs, but launching missiles will only give you range, not speed if the aircrafts speed is relatively low.

A fighter pilot will tell you that it is not impossible to out-manouver a missile that has expended all of it`s fuel and is coasting...

I have read dozens of pilot interviews which stated that there is little tactical advantage of swanning about at 80,000+ft, so they rarely do it. Unless you have "speed". Now, if the F-22 can cruise at Mach 2 at 80,000+ft I would be impressed! That would impart great velocity and range to your AMRAAMS! The F-22 can already do that at 65,000+ft.

The only aircraft that can do 80,000+ft right now at high speed is the Mig-31 and POSSIBLY the F-22.. I may have answered my own question there!!!!

Unread postPosted: 28 May 2006, 20:19
by Angels225
Of the raptor could pull off that sort of peformance,(hell its done stuff only dreams are made of) It make one hell of an interceptor

Unread postPosted: 28 May 2006, 20:54
by Raptor_One
No F-16 can maintain level flight at 80,000 ft. If an F-16 reaches 80,000 ft, it does so in a zoom climb. An F-16's service ceiling or even absolute ceiling is around 60,000 ft. It's about the same for an F-15 too. Despite the F-15's wing area being over twice that of an F-16's, its higher empty weight negates any service ceiling advantage. I highly doubt an F-22 will be maintaining level flight at 80,000 ft. Perhaps 70,000 ft at very high mach.

Unread postPosted: 29 May 2006, 21:02
by Magnum
The ability to pull a lot of g's isn't what makes a high performance fighter. Above the mach you can pull 9g's and have a turn radius the size of Texas. More important is how to have a small turn radius with a high turn rate. Rate being how fast you track around that circle. With thrust vectoring you can accomplish positive rates and radius without pulling a lot of G. Same is true in the Viper. It's best turn speed is actually a range. At the top end you pull more g to max perform while at the low end you only pull about 4-5 g's. Off topic a bit, sorry.

Unread postPosted: 30 May 2006, 06:26
by Brad
sferrin wrote:The higher you are the further your missiles will go. 1. they've got more altitude to trade for range, 2. thinner air for less drag, and 3. less backpressure so you get better ISP out of your motor. As far as the fuel load the YF-22's was given as 23,000lbs internal. Granted they slimmed down the F-22A's fuselage somewhat but I'd be surprised if they lost so much volume that they gave up 5000lbs of fuel if they didn't have to.



Yes I would have been to but luckily I found official unclassified info:

http://www.0x4d.net/files/AF1/R11%20Segment%2012.pdf

This is USAF TO (Technical Order 00-105E-9) and discusses danger areas along with fire/rescue information etc. On pp. 15 you can see the fuel loads of each tank and the total.

Total is 5,450 gallons or 36,515lbs of JP-8. When you remove the 4 external 592 gallon tanks that leaves you with 3,082 gallons or 20,649.4lbs. So Kopp was correct and POGO/Riccioni/Stevenson and his ilk are wrong. That puts the FF at just under 0.31 or about .0308, not the .2775 they suggested.

Brad

Unread postPosted: 01 Sep 2006, 01:43
by DesignAndConquer
Angels225 wrote:About the max Altitude of the raptor, I read some dude took an early block viper above 80,000 ft, In fact the link was posted here, but darn it i forgot where it was, Comsidering the greater T/W ratio of the raptor, I reckon it should be able to go a bit further than that.


I think I read that too. In the Semper Viper edition of Code One with all the Joe Bill Dryden articles. Problem is (and he addressed this) is that its hard to run a jet engine at that altitude unless its specifically trimmed. The SR-71 was one of the few (probably the only) aircraft to be able to trim its engines from the cockpit. But for the moment say that the F-22 has a superb fadec that does it automatically. Now the next problem is sufficient airflow to support combustion. What forward speed would it take to feed the compressor face of an engine like the F110-129 at the air density you'd find at 80,000 feet. If its below the Raptor's public top speed of around Mach 2.x then theoretically it would be possible.

Oh and don't forget needing to plumb the pressure suit into the environmental system.


As always, if I missed/messed up anything, may the experts chime in.

Unread postPosted: 01 Sep 2006, 16:13
by Raptor_One
80,000 ft is not a sustained altitude. It's reached in a zoom climb. Neither the F-16 or the F-22 can cruise at that sort of altitude. Both can surely reach this altitude (and even higher) in a zoom climb though. The F-16 can theoretically perform a zoom climb to an altitude of nearly 100,000 ft. The F-22 will likely go a lot higher. However, sometimes a fighter loses stability at these altitudes before they can actually reach their theoretical maximum.

Unread postPosted: 01 Sep 2006, 18:43
by Purplehaze
80,000 ft is not a sustained altitude. It's reached in a zoom climb. Neither the F-16 or the F-22 can cruise at that sort of altitude. Both can surely reach this altitude (and even higher) in a zoom climb though. The F-16 can theoretically perform a zoom climb to an altitude of nearly 100,000 ft. The F-22 will likely go a lot higher. However, sometimes a fighter loses stability at these altitudes before they can actually reach their theoretical maximum.


More likely to flameout at 100,000 ASL.

Unread postPosted: 01 Sep 2006, 19:34
by Raptor_One
I don't know how much airflow is necessary to keep the combustion process going at those altitudes, but you'd likely have to be going pretty fast. Then again, you have to be going pretty fast at those altitudes just to keep from stalling. Not only that, but you have to have enough airflow over the control surfaces to maintain stability. I have no idea whether you'd starve the engine of oxygen before stalling or losing stability. It's likely aircraft dependent.

Unread postPosted: 01 Sep 2006, 20:36
by sferrin
Raptor_One wrote:I don't know how much airflow is necessary to keep the combustion process going at those altitudes, but you'd likely have to be going pretty fast. Then again, you have to be going pretty fast at those altitudes just to keep from stalling. Not only that, but you have to have enough airflow over the control surfaces to maintain stability. I have no idea whether you'd starve the engine of oxygen before stalling or losing stability. It's likely aircraft dependent.


It really does depend on the engine. U-2s cruised at at least 72,000ft witha J75 and they weren't even going very fast as far as jet aircraft are concerned. Now they use a varient of the F118 (which is a varient of the F110). Where the F-22 is going faster and the engine has a much higher compression ratio (than the J75) well. . . something to think about.

Unread postPosted: 01 Sep 2006, 22:12
by Raptor_One
Oh... I wasn't talking about altitudes in the 70K range. I was talking more like 90-100K range. And by pretty fast, I don't mean SR-71 fast. :) Like someone said in earlier in this thread (I think), if the engine is properly trimmed for high altitude flight (or can trim itself automatically for any condition encountered), high altitude operation might not be a problem. Another thing to consider is that while the engine might not cut out at extremely high altitudes, the amount of thrust output could be next to nothing. Also, what's the stall speed for an F-16 at 90,000 ft? Dare I say supersonic? LOL! If not, it's high subsonic. The F-16's wing is extremely small compared to the F-22's or even the F-15's. How high did the Streak Eagle go, by the way?

Unread postPosted: 01 Sep 2006, 23:27
by snypa777
This quote from the USAF museum website.

"The single-seat F15A on display,

Unread postPosted: 02 Sep 2006, 00:05
by sferrin
Raptor_One wrote:Oh... I wasn't talking about altitudes in the 70K range. I was talking more like 90-100K range. And by pretty fast, I don't mean SR-71 fast. :) Like someone said in earlier in this thread (I think), if the engine is properly trimmed for high altitude flight (or can trim itself automatically for any condition encountered), high altitude operation might not be a problem. Another thing to consider is that while the engine might not cut out at extremely high altitudes, the amount of thrust output could be next to nothing. Also, what's the stall speed for an F-16 at 90,000 ft? Dare I say supersonic? LOL! If not, it's high subsonic. The F-16's wing is extremely small compared to the F-22's or even the F-15's. How high did the Streak Eagle go, by the way?


BTW does anybody here know the details of how in the hell a Mig-29 snagged the sustained altitude record at nearly 95,000 feet?

Unread postPosted: 02 Sep 2006, 01:44
by Raptor_One
Where did you read that a MiG-29 sustained level flight at 95K ft? That sounds... impossible. Who knows though... maybe its lifting body design allows it to continue generating lots of lift at high altitude. It doesn't sound quite right though. I actually have a MiG-29 manual that has CL vs. AoA curves and the reference area used for those coefficients. I could (but doubt I will... hehehe) calculate its absolute ceiling for a given weight and airspeed. And something tells me it won't come out to 95,000 ft under any circumstances. That's outrageous though... what is the MiG-31's absolute ceiling at Mach 2.8? Don't tell me it's not higher than the MiG-29's!!! hahaha....

Unread postPosted: 02 Sep 2006, 04:05
by sferrin
Raptor_One wrote:Where did you read that a MiG-29 sustained level flight at 95K ft? That sounds... impossible. Who knows though... maybe its lifting body design allows it to continue generating lots of lift at high altitude. It doesn't sound quite right though. I actually have a MiG-29 manual that has CL vs. AoA curves and the reference area used for those coefficients. I could (but doubt I will... hehehe) calculate its absolute ceiling for a given weight and airspeed. And something tells me it won't come out to 95,000 ft under any circumstances. That's outrageous though... what is the MiG-31's absolute ceiling at Mach 2.8? Don't tell me it's not higher than the MiG-29's!!! hahaha....


It's real. Why do you think I'm going "WTF?" just like you? :shock: I'd read about it a long time ago (it happened long enough ago that when they brough the Blackbird back OUT of retirement briefly they considered taking the record back but nothing ever came of it). Some solar-powered all-wing NASA job holds the record now at 96,000 something feet but the Mig-29 held it for quite a while.

Unread postPosted: 02 Sep 2006, 06:26
by Raptor_One
Well... it must be the lifting body design. The thing was probably flying along at high Mach and some strangely high AoA for sustained supersonic flight. The lifting body design must perform very well at high altitudes. Also, the MiG-29 is extremely light. I doubt an F-14 our Su-27 could accomplish the same type of feat simply because they're too damn heavy. The MiG-29 is for sure the smallest high-performance aircraft that acts as one big lifting surface. I wonder how fast it was going up there and how it actually climbed to that altitude. You might not be able to get to such an altitude and sustain flight there without some crazy climb profile.

Unread postPosted: 02 Sep 2006, 22:02
by habu2
Considering the altitude density at 95Kft I doubt a lifting body design is much of a factor....

Unread postPosted: 02 Sep 2006, 23:35
by Raptor_One
habu2 wrote:Considering the altitude density at 95Kft I doubt a lifting body design is much of a factor....


The more lifting area you have at those altitudes, the better. Using most of the aircraft as a lifting surface is more efficient than only using the wings. The main fuselage will generate some lift at an angle of attack regardless of shape, but the lift to drag ratio of the fuselage alone could be terrible. However, if the fuselage is purposefuly shaped to generate a good lift/drag ratio, you're making optimum use of space (in an aerodynamic sense). That's the idea behind the B-2, isn't it?

Unread postPosted: 03 Sep 2006, 09:43
by DesignAndConquer
Raptor_One is right about that part. Wings are less and less useful the higher up you go. Unless you have a very high aspect ratio wing (U-2/TR-1) or a very lowly loaded wing (NASA Helios) in order to stay aloft at high altitudes while remaining subsonic. Even if your airspeed is down to 100 knots, you may well be supersonic so using flaps and other high lift devices becomes less attractive.
The lifting body design does away with the wing and its associated intereference and form drag. In addition, they are by design of very low aspect ratio. If you can still find NACA Technical Note #539 and Report #431, you'll find that between an aspect ratio of approx. 0.75 to 1.50 there is a "marked delay in the breakdown of the longitudinal flow as the angle of attack of the airfoil is increased." Pretty much they're defining vortex lift, something that airplanes from the Draken to the Concorde to the Viper utilize in their designs.
The point (if I can bring it all together) is that the Mig-29 is shaped like a guitar pick and has a lot of hidden lifting area not counted in its wing area. Low wing loading + a lifting body design + powerful engines and a minimal fuel load = high sustained altitude. Could the Raptor do it? Of course. Will we ever see it? Who knows, but its fun to imagine.

Whew. Reading all those books finally paid off :)

Unread postPosted: 03 Sep 2006, 10:40
by sirius
It's not just maximum G that's important, but the rate of onset of Gs. A pilot can black out going from 2 to 4 Gs if the rate is high enough, while going up to 8 Gs at a slower rate wouldn't.

Jeff

Unread postPosted: 03 Sep 2006, 10:42
by sirius
Raptor_One wrote:...but if you calculate the possible Mach numbers that 16000 MPH equates to ...



I assume that's in afterburner? :D

Jeff

Unread postPosted: 03 Sep 2006, 14:34
by Raptor_One
Did I say 16,000 MPH? :D Yes... that would be in afterburner alright. More specifically, afterburner stage "ludicrous".... for "ludicrous speed".

Unread postPosted: 10 Sep 2006, 15:08
by 174Cobra
but only at Dark Helmet's command.... :applause: