F-22 Speed = Mach 2.84 Calculations!!

Originally posted by bdn12
About the Concorde going M2.2 for thousands of miles: Yes, it cruised at supersonic speeds for thousands of miles, but not Mach 2.2. The fastest Atlantic crossing for the Concorde was around 2 hours and 53 minutes. The distance from New York to London is 3463 miles. If we do simple math, that averages out to a speed of ~1200 mph, which isn't Mach 2.2. Some other aircraft which could probably keep up with the Concorde are the TSR.2, B-58, and Mirage IV. Plus, those aircraft have aerial refueling, so in anything beyond about 4000 miles, the Concorde would be toast. The other obvious aircraft are the SR-71 and XB-70. SR-71 combines M3 speed with refueling. Even though the XB-70 didn't have aerial refueling, it could go Mach 3 for over 6000 miles.

Concorde cruised at up to 60,000ft and Mach 2.02 regularly on its transatlantic routes, Mach 2.2 was its maximum rated speed and rarely used.

At 60,000ft the speed of sound is 660mph give or take, meaning 1320mph for Mach 2, again give or take.

Guys, the thread is long dead - it got bumped from 2004.. You'll be arguing with ghosts

Originally posted by Stoo
Guys, the thread is long dead - it got bumped from 2004.. You'll be arguing with ghosts

Im 'discussing' a point with the person who bumped the thread

Originally posted by Stoo
Guys, the thread is long dead - it got bumped from 2004.. You'll be arguing with ghosts

Some of us "ghosts" are still here though...

Originally posted by WestPoint23

Some of us "ghosts" are still here though...

BOO!!!!!

Sorry, I couldn't help it...

Anyway, the original post is unfortunately misguided.


At any aircrafts top speed, thrust = drag.


Thus you simply cannot discount drag, or rather as done here - assume that the drag force of a MiG-29 @ 1490 mph equals the F-22 at 1490 mph... and that the drag continues to increase linearly with speed.


In subsonics, drag squares with speed, and in supersonics, its even more than that [power of 5/2 or something like that IIRC].

[edit on 4/8/07 by kilcoo316]

As I've said before the Raptor's top speed is the speed at which the airframe starts to critically fail. It has enough thrust and low enough drag to cripple the airframe.

Originally posted by WestPoint23
As I've said before the Raptor's top speed is the speed at which the airframe starts to critically fail. It has enough thrust and low enough drag to cripple the airframe.

Probably correct there.


Was it you (or was it someone else) that suggested it was limited by the canopy?

Originally posted by intelgurl
BOO!!!!!

Sorry, I couldn't help it...

You're more like Major Kusanagi though

(Ghost in the Shell)


Back on topic, going back a way, then pretty much everyone covered it already - drag, heat-soak, materials, construction, and the difference between supersonic and subsonic aerodynamics make any such sort of "quick calculation" pointless and hopelessly inaccurate..

You might as well try to calculate the maximum velocity of a thrown pizza for all the good it will do you..

(Mine's a hawaiian if you're throwing them this way... )

I believe I read when in prototype stage the max speed was mach 3.0

To put it in perspective, during mach tests, aurora reached mach 6+ as evidenced by quick sequential micro tremors registered by local richter scales near the nevada lake beds.

My point being that your 2.84 approximation is probably sound for max speed with no headwind.

Originally posted by jfj123
To put it in perspective, during mach tests, aurora reached mach 6+ as evidenced by quick sequential micro tremors registered by local richter scales near the nevada lake beds.

Heh, it really makes me laugh when people talk about the 'Aurora' in definite, certain terms like its existence and performance has been confirmed.

Here are the aurora facts.
And feel free to call the test plane whatever you like.

visually sited during mach tests via con trails
matching seismo reading during super sonic testing.

The government tests alot of prototype planes.

I'm sorry I don't have an official press release but come on it's just a test plane.

I do know for sure a government plane has been tested and exceeded mach 6. We can call it the Fred Flintstone plane if you like.

Originally posted by jfj123
I believe I read when in prototype stage the max speed was mach 3.0

To put it in perspective, during mach tests, aurora reached mach 6+ as evidenced by quick sequential micro tremors registered by local richter scales near the nevada lake beds.

My point being that your 2.84 approximation is probably sound for max speed with no headwind.

Please, tell us how headwind affects top Mach speed...

headwind pushes at plane as plane goes into wind. Wind resistance could lower max capable speed.

Originally posted by jfj123
headwind pushes at plane as plane goes into wind. Wind resistance could lower max capable speed.

It would lower the groundspeed.


Not the airspeed.

headwind is a limiting factor in max air speed. Thats the way it is. If it's a limiting factor on the ground in 2 dimensions, it's a limiting factor in the air in 3 dimensions.

look at it this way,
If an aircraft is traveling into a 700 mph wind, and the aircraft is traveling at 600 mph what is the actual speed of the craft?

Originally posted by jfj123
headwind is a limiting factor in max air speed. Thats the way it is. If it's a limiting factor on the ground in 2 dimensions, it's a limiting factor in the air in 3 dimensions.

No, its NOT the way it is.



Airspeed is airspeed, and any wind speed or direction is utterly irrelevant.




As for your 2nd point.


If an aircraft has an AIRSPEED of 600 mph into a 700 mph headwind, then it has a 100 mph GROUNDSPEED in the opposite direction as its facing.


Quoted max speed is ALWAYS airspeed. Always has been, always will be. When they quote the altitude for it, it will be for that altitude in ISA conditions.

[edit on 5/8/07 by kilcoo316]

Heres a theory to consider, since you all have engineering degrees right ? Right. Okay....

We all know there is information about this and many other fighter Jets that are HIGHLY contained within a company like Lockheed and the Military itself. You can calculate and gather, and research as much as you want. The fact is ... You're all wrong. This plane does things you could never have imagined and even more that you NEVER see at an air show.

Try Mach 3.5 to 4

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

Well... I know at least 3 people on here do.

Originally posted by Anonymous ATS
Try Mach 3.5 to 4

Try Mach 2.3 to 2.4.