F-22 Afterburner

757 actually has one of the best T/W ratios around depending on engine choice, it's a bit of a 'hotrod' according to pilots.

I'd add the YF-23 into that list since you have experimental and prototypes, give it the YF120 engine and it would eat the F-22 for breakfast speed wise, much less drag and more powerful engine. The F-16/F-15 chase planes couldn't keep up even using full reheat and it wasn't using reheat at all

Originally posted by Murcielago

Originally posted by ORIEguy
But I doubt the skin would take heating too well.

Why?
The majority of the Raptor is Titanium.
People say this all the time, why do people think the Blackbirds speed was limited by its skin temp.

Titanium's melting point is over 3,000 degrees F.
The nose of an aircraft at mach 3 is a mere 572 degrees.
mach 6 is around 1,325 degrees.

I have seen no proof at all, that the skin temps are holding back speed limits in aircraft.

[edit on 18-1-2006 by Murcielago]

In addition to what's been said:
I should have looked for F-22 specific info, as i was speculating based on general a/c specs. Titanium is extremely expensive and heavy, so most aircraft use aircraft aluminum for the majority of the materials, with heavy materials like titanium(or steel when you really want to skimp) reserved for structural stiffening. For example, the F-14 used titanium for the wing box for its swing wing mechanism.

In addition, most stealthy aircraft use a composite of some sort(presumably some carbon composites, which resists heat well IIRC AND has stealth properties), but the composite binding matrix does not resist heat well. However, they are very strong structually.

As a disclaimer though...it's been damn near forever since I've done materials selection work, so my memory could be pretty fuzzy.

Anyway, here is an interesting link: www.allstar.fiu.edu... which provides info on the make up of the materials, by weight though.
And according to this, yes most of it is titanium. It seems the F-22 was designed with high speeds and associated temperatures in mind, which is of course, the logical thing to do.
However, the F-22's SKIN which is obviously going to feel the most heat is made mostly of composites(which generally don't resist heat as well), which also matches the needs of a stealth fighter. But they used bismaleimide (BMI) composites, which are known to have higher temperature resistance.

I remember hearing that the wing box and main fuselage of the rapotor was the strongest to ever be developed for any aircraft.

Train

If this race was around 5000 km, my top ten order would be:
1. SR-71
2. XB-70
3. Mig-25/31
4. Sukhoi T-4
5. Concorde
6. TU-144
7. YF-23
8. F-22
9. BAC TSR.2
10. Mirage IV

Originally posted by BigTrain
This is what I want to see

I want to see a test with an f-14, f-15 and f-18 and maybe an f-16 even though it is single engined, and I want to see all 4 or 5 jets flying at level right next to each other all at about 400-500 mph at about 300-500 feet off the ground and then I want them all to smash the throttles and pull it str8 up, I want to see which bird blows to the highest altitude straight up, which has the greater accel and which has peak velocity and I want to see it on Discovry HD theater taken with the same cameras used to view a space shuttle launch so we can have a real show.

Who else would want this?

Train

I'd buy that for a dollar and a bucket of popcorn for both of us! I'd love to see that test as well!

Delete this please.

[edit on 2-7-2007 by carnival_of_souls2047]

Accident, plz delete. My apologies to those hurt by this accidental post.

[edit on 2-7-2007 by carnival_of_souls2047]

I"m terribly sorry for this repeat accidental post. By all means delete it at your leisure.

[edit on 2-7-2007 by carnival_of_souls2047]

Ditto, please delete at your convience.

[edit on 2-7-2007 by carnival_of_souls2047]

Sorry again. Please delete this accidental machine gun post.

[edit on 2-7-2007 by carnival_of_souls2047]

Please delete.

[edit on 2-7-2007 by carnival_of_souls2047]

Lastly. please delete and thank you for your understanding in this matter.

[edit on 2-7-2007 by carnival_of_souls2047]

People say this all the time, why do people think the Blackbirds speed was limited by its skin temp.

Wasn't limited by skin temp, but by Compressor inlet temp, the flight manual states it quite clearly:

"Mach 3.2 is the design Mach number. Mach 3.17 is the maximum scheduled cruise speed recommended for normal operations. However, when authorized by the Commander, speeds up to Mach 3.3 may be flown if the limit CIT of 427 degrees C is not exceeded."

www.sr-71.org...

The limiting factor in the Raptor's top speed is the airframe not the engines. The F119 is capable of withstanding much more pressure and heat while putting out more thrust than the airframe can safely handle.

The real numbers are in the following ball park (I wont pretend to state specifics as none of us know). Top end supercruise speed depending on specific weight is around Mach 1.8 - Mach 1.9. I hesitate to put Mach 2 because it may have to light burners to break through but otherwise I have no problem believing it can sustain such a speed. Plenty of pilot comments indicate that. Max top speed is the speed at which the airframe starts to fail (I'm serious), there are no electronic speed restrictions on the F-22. And as I said before the F119 engines are capable of a lot more. My guess would be that anything above Mach 2.5 is for all purposes self destructive.

The F-22 has the big bad engines for thrust vectoring maneuvers. A fighter really don't need anything above Mach 2.5 . However The Air Force wanted a plane that was at least as good as the F-15 in speed for its air intercept missions. Given that requirement I'm sure if the Raptor had to chase down some MIGs and he didn't care about stealth I'm sure Lockheed made sure it can take it to the limits of what its engines can put out. I don't think we will hear about it for a long time, Unless one just has to do it sooner. I have seen a former Blackbird pilot who stated that Russia sent its MIG 25s to shoot him down on many occasions and they could easily out run them so the MIGs adapted a plan to box him in. Unfortunately for the Russians the SR-71 would climb and turn and say by by to them. He also stated that they would do a huge loop and get a tremendous speed boost up to Mach 4.1 for very dangerous passes over Russia. I cant wait to see the son of Blackbird the SR-72, Its flying now and is smaller and faster than Mach 5.