F-22 Speed = Mach 2.84 Calculations!!

Originally posted by Anonymous ATS
Heres a theory to consider, since you all have engineering degrees right ? Right. Okay....

Try Mach 3.5 to 4

That's just wee bit optimistic don't you think?
Sure it has a greater thrust to weight ratio than the SR-71 but there's this thing called "aerodynamics" and quite frankly the F-22 is simply not sleek enough to go that fast.

I think many recall what Paul Metz said when he was head test pilot for the F-22 - he said the F-22 has a top speed greater than 1,600 mph (Mach 2.42) and its climb rate is faster than the F-15 Eagle.
Additionally Gen Moseley said it supercruised at Mach 1.7, which is pretty incredible too.




[edit on 9-17-2008 by intelgurl]

reply to post by intelgurl


From first hand pilot quotes I've come to believe that the F-22s top speed limit is the speed at which the airframe starts to fail and the aircraft can no longer maintain structural integrity. The engines have enough thrust, and the jet is aerodynamic enough to basically destroy itself if not careful. As far as its top safe speed, I too think it's below Mach 2.5, but not by much. The now infamous Dozer (damn ridiculous AFOSI) stated that its top super-cruise speed is not that far behind its top overall speed and that the F-22 was very much a Mach 2 capable fighter. A statement which should rightly lead one to ask, Mach 2 super-cruise given certain paramatars?

[edit on 17-9-2008 by WestPoint23]

ACCORDING TO WIKI RENEWED IT IS 2.25 MACH, NOT SO FAST AS SOMEBODY IMAGED.

Originally posted by emile
ACCORDING TO WIKI RENEWED IT IS 2.25 MACH, NOT SO FAST AS SOMEBODY IMAGED.

Emile, Mach is relative to altitude, therefore 1,600 mph at sea level may be approximately Mach 2.1 but at 60,000 feet 1,600 mph equates to Mach 2.42.

Here's your values:
At sea level, Mach 1 = 760 mph
At 50-60,000 feet, Mach 1 = 660 mph

1,600/660 = 2.42

No vivid imagination here, just facts.

In the Wiki description of the F-22 it also has the reference to Paul Metz's statement regarding the F-22 flying at 1,600 mph at altitude.

Unfortunately, in the specs Wiki provides at the bottom of the page they did a flawed calculation to get their Mach 2.25 number as they did not take into account the change in Mach at cruising altitude.

"F-22 has a top speed greater than 1600 mph": wikipedia.org

"Maximum speed: ≈Mach 2.42 (1,600 mph, 2,575 km/h) at high altitude"

First off, you have the Raptors numbers all wrong! max takeoff is 72,000lbs (It will never be at that weight while fighting) The weight that the Raptor will be fighting at is 58,200lbs! A 30,300lb air frame, 2,680lbs of air to air weapons, 6 Aim120's, 2 Aim9's, 480rnds of 20mm to go along with it's massive 25,000lbs of internal fuel and the pilot with gear 220lbs.

The official thrust of the F119 is 37,800lbs X 2 =75,600lbs.

Thrust to weight ratio in an air to air configuration is right at 1.30:1 on the runway and over 1.50:1 at the fight scenario, this tops all fighters! Compare this to the F-15s air to air of 1.10:1 Typhoons at 1.08:1, Mig-35 0.98:1 Rafales 0.91:1, SU-27's 0.89:1 and the SU-30's 0.81:1.

I work for Pratt & Whitney and have for 14 years, my Dad worked for PW and was one of the engineers on the original F100 team. I was on the F119-PW-100 team for 10 years. I'm now working on the F119-PW-200.

I'll let you all figure out the speed of the Raptor, but remember this, the Raptor will always have the weapons and fuel internally when it counts! which means far less resistance compared to any other fighter, even when they don't hang weapons! Compare the lines of a Typhoon then the Raptors! The Raptors body panels are near invisable, they seem to melt into each other and the lines can't be matched by any aircraft. You wont find any angles pointing in the wrong direction to upset it's aerodynamics!

The F119's have an upper intake that bypasses the engine entirely during extreme high speeds , these stay closed when maximum stealth is needed. The structure and materials used on the F-22's air frame and skin are able to handle very high speeds also. Think of it this way>

More slippery than an F-15......

Its supercruising speed is more important that its top speed. Being able to stay in the air at M1.7 for quite a while, is much more important than flying around at .9M and then having 10 minutes of afterburner time to go to M2.

The spped of sound at sea level is 761 mph or 661 knots, the speed of sound at 11 000 m−20 000 m (Cruising altitude of commercial jets) is 660 mph or 573 knots.

fyi

Originally posted by Anonymous ATS
First off, you have the Raptors numbers all wrong! max takeoff is 72,000lbs (It will never be at that weight while fighting) The weight that the Raptor will be fighting at is 58,200lbs! A 30,300lb air frame, 2,680lbs of air to air weapons, 6 Aim120's, 2 Aim9's, 480rnds of 20mm to go along with it's massive 25,000lbs of internal fuel and the pilot with gear 220lbs.

The official thrust of the F119 is 37,800lbs X 2 =75,600lbs.

Thrust to weight ratio in an air to air configuration is right at 1.30:1 on the runway and over 1.50:1 at the fight scenario, this tops all fighters! Compare this to the F-15s air to air of 1.10:1 Typhoons at 1.08:1, Mig-35 0.98:1 Rafales 0.91:1, SU-27's 0.89:1 and the SU-30's 0.81:1.

I work for Pratt & Whitney and have for 14 years, my Dad worked for PW and was one of the engineers on the original F100 team. I was on the F119-PW-100 team for 10 years. I'm now working on the F119-PW-200.

I'll let you all figure out the speed of the Raptor, but remember this, the Raptor will always have the weapons and fuel internally when it counts! which means far less resistance compared to any other fighter, even when they don't hang weapons! Compare the lines of a Typhoon then the Raptors! The Raptors body panels are near invisable, they seem to melt into each other and the lines can't be matched by any aircraft. You wont find any angles pointing in the wrong direction to upset it's aerodynamics!

The F119's have an upper intake that bypasses the engine entirely during extreme high speeds , these stay closed when maximum stealth is needed. The structure and materials used on the F-22's air frame and skin are able to handle very high speeds also. Think of it this way>

More slippery than an F-15......

Could the F119 be mounted on the F-15? I believe they have about the same diameter ( without the exhaust) but I'm not sure.

How much more power does the F119 produced in military thrust compared to the F100-PW-232 at say Mach 1.5?

Thx.

Could the F119 be mounted on the F-15? I believe they have about the same diameter ( without the exhaust) but I'm not sure.

Probably; but not without substantial modification.

At supersonic speeds the F-119 will produce double the dry thrust of an F-100-229...

And F-22 has around 18500lb of fuel, not 25,000. Bleed doors are removed on later models IRC.



[edit on 5/3/2009 by C0bzz]

I've seen the x2 figure vs the F100, but as far as I know they were comparing it with the PW-100.

I would like to know the difference with the -232.

I've read also that the -232 has been tested at more than 37000lbs static, which is about the same as the F119.

The 232 introduces the some of the F119 technologies, including the same fan I think.

The F119 has a very low bypass ratio (0.2) so perhaps the F-15's air intake would do the trick. And with its variable intake the F-15 would exploit the engine even better at high speed.

Originally posted by TACHYON

Originally posted by NickS1004
If the F-22 does indeed have variable intakes, i would say its mach 3 capable, if it doesnt.. mach 2 is more likely

>>I know a way to find out.
From:
www.grc.nasa.gov/WWWK-12/WindTunnel/Activities/lift_formula.html ,
the folowing was abstracted:

L = (1/2) d V^2 S Cl
where,
L = lift in lbs.
d = air density at a particular altitude
V^2 = velocity squared in ft/sec (not ft/sec/sec, that's acceleration)
Cl = coefficient of lift, a decimal figure, usually less than 1.

Also they listed d = .00046 @ 4,000'
= .000362 @ 50,000'
= .000285 @ 55,000'
by division of higher altitudes into lower ones, I extrapolate, multiplying by .78 for each 5,000 ft. increase:
.0001055 @ 70,000'
.00008223 @ 75,000'
.0000642 @ 80,000'

Now assume the wing area and flying weight (given on the site above) is 830 sq. ft. and 56,000 lbs.; and the Cl is .5 @ 4 deg. angle-of-attack (also graph extrapolated on the site), and 1,900 ft/sec as forward air speed, then,

L = (1/2) * .00008223 * 3,610,000 * 830 * .5 = 61,596.4 lbs.
(The F-22 has the wing lift to fly level at Mach 2.9 -3.0 at 80,000 ft. according to a subsonic-applicable algebraic formula)

This was calculated on my TI-30.
Whether or not the engines or intakes will function at that speed or altitude is still questionable. I know the subsonic *maximum speed* formula only by memory, but I can't provide a reference other than a 50 yr. old college textbook that's in storage now.