F-22 Raptor speed

Anything goes, as long as it is about the Lockheed Martin F-22 Raptor
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idesof

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Unread post29 Sep 2006, 16:30

habu2 wrote:What most everyone here seems to fail to grasp is the simple fact that no matter what some general says or some pilot brags or some reporter misquotes, it's none of your f***ing business what the top speed, cruising speed, or supercruise endurance is. The performance parameters of the F-22 are classified, and no one who has access to or knowledge of those parameters is going to (accurately) quote them in public. If they do it will be a short trip to Leavenworth, and they know that.

When some one breaks into your house do you say "I have a gun and 9 bullets" ??? No, you just shoot the m***** f***** and be done with it. You never show your full hand to your enemy.


Ah, well, problem is, the USAF repeatedly talks about the Raptor's performance. Offers figures. Promotes its plane. So long as they go public with any piece of equipment, and proceed to talk it up, it is fair game to discuss it at will. So, there you have a pilot, talking about going 800 miles in 25 to 30 minutes. If you have a problem, take it up with him. The cat is out of the bag, and nothing you can say will now make it go back inside.
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idesof

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Unread post29 Sep 2006, 16:36

toan wrote:Personally, I think if you change "800 miles" to "800 km", then we will get a more reasonable result:

1. For their performance, which started at 2:40 p.m., Shower and Bergeson took off from Langley, 800 "miles --> km" away, at about 1:25.

A: 800 km / 1.25 hr = 640 km/hr = With the average speed of 0.6 Mach for this 800 km long trip that fits the National laws (Of course, the average speed is not equal to the maximal speed during this trip).


2. But we did the math and figured we could be there if we supercruised in about 25 or 30 minutes.

A: 800 km / 25~30 mins = 1600~1920 km/hr = With the average supercruise speed of 1.51~1.81 Mach for this 800 km long trip.


Toan, I said EXACTLY the same thing. However, Sferrin said he calculated the distance as being 800 miles. I have a feeling that someone is messing up their metric and English units. Again, if NASA and Lockheed and dozens of rocket scientists (literally rocket scientists) can screw up with their measurements, so can two pilots who get carried away bragging about their plane.
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sferrin

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Unread post29 Sep 2006, 16:51

habu2 wrote:What most everyone here seems to fail to grasp is the simple fact that no matter what some general says or some pilot brags or some reporter misquotes, it's none of your f***ing business what the top speed, cruising speed, or supercruise endurance is. The performance parameters of the F-22 are classified, and no one who has access to or knowledge of those parameters is going to (accurately) quote them in public. If they do it will be a short trip to Leavenworth, and they know that.

When some one breaks into your house do you say "I have a gun and 9 bullets" ??? No, you just shoot the m***** f***** and be done with it. You never show your full hand to your enemy.


ROFL!! This is info out of a nationally published (probably internationally) magazine. Not much of a secret now is it? Personally I can't imagine a pilot spilling the beans one-on-one let alone when talking to a MAGAZINE for God's sake. As to whether or not it's our business of course it isn't. That doesn't mean we can't speculate until the cows come home. Or do you think the other side doesn't have people who know aerodynamics far better than us armchair generals who are doing the same thing? Is some big secret going to get out because us amatuers are sitting around the water cooler bullsh!tting? Doubt it.
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toan

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Unread post29 Sep 2006, 16:51

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

Page 16:

The percentage of Titanium for the materials of Raptor's airframe is around 40%, which is roughly equal to Su-27, whose airframe has 41% Titanium.
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sferrin

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Unread post29 Sep 2006, 16:53

idesof wrote:
toan wrote:Personally, I think if you change "800 miles" to "800 km", then we will get a more reasonable result:

1. For their performance, which started at 2:40 p.m., Shower and Bergeson took off from Langley, 800 "miles --> km" away, at about 1:25.

A: 800 km / 1.25 hr = 640 km/hr = With the average speed of 0.6 Mach for this 800 km long trip that fits the National laws (Of course, the average speed is not equal to the maximal speed during this trip).


2. But we did the math and figured we could be there if we supercruised in about 25 or 30 minutes.

A: 800 km / 25~30 mins = 1600~1920 km/hr = With the average supercruise speed of 1.51~1.81 Mach for this 800 km long trip.


Toan, I said EXACTLY the same thing. However, Sferrin said he calculated the distance as being 800 miles. I have a feeling that someone is messing up their metric and English units. Again, if NASA and Lockheed and dozens of rocket scientists (literally rocket scientists) can screw up with their measurements, so can two pilots who get carried away bragging about their plane.


Except that it 800 MILES from Langley to Oshkosh.
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idesof

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Unread post29 Sep 2006, 17:11

sferrin wrote:
idesof wrote:
toan wrote:Personally, I think if you change "800 miles" to "800 km", then we will get a more reasonable result:

1. For their performance, which started at 2:40 p.m., Shower and Bergeson took off from Langley, 800 "miles --> km" away, at about 1:25.

A: 800 km / 1.25 hr = 640 km/hr = With the average speed of 0.6 Mach for this 800 km long trip that fits the National laws (Of course, the average speed is not equal to the maximal speed during this trip).


2. But we did the math and figured we could be there if we supercruised in about 25 or 30 minutes.

A: 800 km / 25~30 mins = 1600~1920 km/hr = With the average supercruise speed of 1.51~1.81 Mach for this 800 km long trip.


Toan, I said EXACTLY the same thing. However, Sferrin said he calculated the distance as being 800 miles. I have a feeling that someone is messing up their metric and English units. Again, if NASA and Lockheed and dozens of rocket scientists (literally rocket scientists) can screw up with their measurements, so can two pilots who get carried away bragging about their plane.


Except that it 800 MILES from Langley to Oshkosh.


Right. I don't disagree with that, as I noted. However, do you think perhaps the pilot in question mixed up his English and metric units?

However, I just crunched the numbers. From Langley to Oshkosh, it took them one hour and 15 minutes, for an average speed of 640 mph. As stated, for an 800-mile trip, that is indeed equivalent to about Mach 0.9. They should have known that to say "25 to 30 minutes" it would mean they would have to go 2.5 to 3 times as fast. It really is puzzling.

By the way, they cite sonic boom as a concern while flying over CONUS. Question: can one get any kind of an accurate fix on an airplane on the basis of its sonic boom? Now, while the hypothetical listening station would already be far behind the airplane by the time the sonic boom hits it, could it relay the info to a station further up ahead? Tell an IR sensor, for instance, exactly where to look? I don't want anyone in the U.S. military to answer this question, nor to threaten me, please. I am asking CIVILIANS with some knowledge of aerodynamics and without any sort of security clearance. Thank you.
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Unread post29 Sep 2006, 17:31

Question: can one get any kind of an accurate fix on an airplane on the basis of its sonic boom?


Yes, in fact there is a similar system that uses multiple microphones distributed in an urban area to determine the location of gun shots. For an air defense system you'd need a hell of a lot of microphones though... and all that effort could be defeated by just not flying supersonically until the SAM sites have been neutralized.
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Unread post29 Sep 2006, 17:39

I have three possible explanations I will toss out.

Option 1 (which I consider to be far and away to most probably):
Shower was simply speaking in hyperbole. Grossly exagerating the time saving to make a point and/or trying to be a slightly amusing.

Option 2 (my least 'favorite' option):
In doing the math, they mistakenly used the speed of sound at sea level and held it to altitude. At sea-level, the speed of sound is about 760 (mph), so to cover 800 miles in 30 minutes the required average speed of 1600 MPH comes out to about Mach 2.1. Still a high number, but more reasonable than some of the '3-ish' numbers that have been thrown around.

Option 3 (my second 'favorite' option):
He either mispoke or was misquoted. What he intended to say (or actually said) was that they would have 'saved' 25-30 minutes. So, assume the baseline 1 hour 15 minutes, and subtract 30 minutes. At 45 minutes, the 800 mile trip requires an average speed of about 1070 mph, which just happens to be Mach 1.62 at 40k - a number much more reasonable and inline with published data.
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Unread post29 Sep 2006, 17:43

Raptor_claw wrote:I have three possible explanations I will toss out.

Option 1 (which I consider to be far and away to most probably):
Shower was simply speaking in hyperbole. Grossly exagerating the time saving to make a point and/or trying to be a slightly amusing.

Option 2 (my least 'favorite' option):
In doing the math, they mistakenly used the speed of sound at sea level and held it to altitude. At sea-level, the speed of sound is about 760 (mph), so to cover 800 miles in 30 minutes the required average speed of 1600 MPH comes out to about Mach 2.1. Still a high number, but more reasonable than some of the '3-ish' numbers that have been thrown around.

Option 3 (my second 'favorite' option):
He either mispoke or was misquoted. What he intended to say (or actually said) was that they would have 'saved' 25-30 minutes. So, assume the baseline 1 hour 15 minutes, and subtract 30 minutes. At 45 minutes, the 800 mile trip requires an average speed of about 1070 mph, which just happens to be Mach 1.62 at 40k - a number much more reasonable and inline with published data.


Ah, third option is my favorite. Good work!
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sferrin

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Unread post30 Sep 2006, 01:20

Raptor_claw wrote:I have three possible explanations I will toss out.

Option 1 (which I consider to be far and away to most probably):
Shower was simply speaking in hyperbole. Grossly exagerating the time saving to make a point and/or trying to be a slightly amusing.

Option 2 (my least 'favorite' option):
In doing the math, they mistakenly used the speed of sound at sea level and held it to altitude. At sea-level, the speed of sound is about 760 (mph), so to cover 800 miles in 30 minutes the required average speed of 1600 MPH comes out to about Mach 2.1. Still a high number, but more reasonable than some of the '3-ish' numbers that have been thrown around.

Option 3 (my second 'favorite' option):
He either mispoke or was misquoted. What he intended to say (or actually said) was that they would have 'saved' 25-30 minutes. So, assume the baseline 1 hour 15 minutes, and subtract 30 minutes. At 45 minutes, the 800 mile trip requires an average speed of about 1070 mph, which just happens to be Mach 1.62 at 40k - a number much more reasonable and inline with published data.



3 makes the most sense.
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Unread post30 Sep 2006, 07:02

You guys are missing the boat on the Raptors speed. Take note how altitude is often mentioned indirectly by official sources (I'll dig up a quote)

The F-22 will consistantly operate in the 50-60,000 foot range. perhaps you guys can figure out Mach at 60,000ft and apply that to your question. Then the answer will fit.
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Unread post30 Sep 2006, 07:05

read this, while the pilot is not quoted as saying 60,000ft, note what he does say about altitude.

http://www.klas-tv.com/Global/story.asp ... v=168XQUgV
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Unread post30 Sep 2006, 08:04

bf-fly wrote:The F-22 will consistantly operate in the 50-60,000 foot range. perhaps you guys can figure out Mach at 60,000ft and apply that to your question. Then the answer will fit.


Above about 37,000 feet the speed of sound doesn't change (in terms of true airspeed). Calibrated (and equivalent) airspeeds do change as altitude changes for a constant Mach, but true airspeed doesn't. So, for this case, the answer no different - whether you are at 37,000 or 60,000 feet.
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Unread post30 Sep 2006, 08:24

So with all this rampant speculation about what he said, what he might have meant to say, what alt they were at, if he meant max supercruise over an 800 mile circuit, if he meant 800km or 800 miles, if he meant he would have saved 25-30 minutes ad nauseum.

It pretty much puts us right back where we were on page 1 when Raptor_One stated that trying to extrapolate the -22 supercruise speed based on one interview is silliness.
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Unread post30 Sep 2006, 10:22

From the height of around 36,000 fts to the height of around 165,000 fts is the range of Stratosphere. Because of the ozone layer, the temperature in the whole Stratosphere is generally the same, so the sonic speed in the whole Stratosphere is also generally the same (Mach 1 = 295 m/sec = 1,062 km/hr = 660 mile/hr at the height of Stratosphere).

Therefore, the declaration of supercrising with the speed of 1,600 mph to 1,920 mph at the height of 40,000 to 70,000 fts is equal to declare that Raptor could cruise with the speed of Mach 2.42 to 2.91 without using A/Bs in Stratosphere, and theoretically, its maximal speed should have to reach from Mach 3.5 to even Mach 5.0+ with the help of A/Bs.

If this were really the truth, then many hypersonic striking projects that USAF and USN are investing now should be pointless and meaningless........
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