F-22 RAM Coatings/Limits on speed?

rhoads56 · by **rhoads56** » 26 Apr 2017, 00:13

Hey all,

I know this is an old topic, but I have been curious for a long time if the F-22s RAM coatings/cockpit glass limit max speed at altitude. I've heard multiple claims that the F-22 is limited to M2.0 for that reason. I've read other posts on here that claim that the F-22 is faster than the F-15. This leads me to some confusion.

NO, I am not looking to know the F-22s max speed, I know it is still classified. But I would like to know what limitations features like RAM coatings and cockpit glass temps etc. might have on performance. I also realize that a fixed inlet doesn't necessarily mean the airplane can't accelerate past M2. Any insight on this? Thank you all!

Rhoads

popcorn · by **popcorn** » 26 Apr 2017, 00:23

There used to be a pic of a F-22 on the web with the skin ablated off it's nose and smeared all over the canopy after apparently exceeding the speed limit. Not good.

rhoads56 · by **rhoads56** » 26 Apr 2017, 00:34

popcorn wrote:There used to be a pic of a F-22 on the web with the skin ablated off it's nose and smeared all over the canopy after apparently exceeding the speed limit. Not good.

Hey Popcorn,

Thanks for the reply. I've seen that pic, pretty crazy. I guess ultimately my question is whether the material properties of the coating itself aren't designed for speeds past Mach 2, a figure that I hear a lot.

wrightwing · by **wrightwing** » 26 Apr 2017, 03:52

M2 isn't the limit for durability.

Corsair1963 · by **Corsair1963** » 26 Apr 2017, 06:21

popcorn wrote:There used to be a pic of a F-22 on the web with the skin ablated off it's nose and smeared all over the canopy after apparently exceeding the speed limit. Not good.

Yes, but the F-22 now has a new coating. So, does that even apply anymore???

rhoads56 · by **rhoads56** » 26 Apr 2017, 17:43

wrightwing wrote:M2 isn't the limit for durability.

I figured it wasn't. Can you elaborate any further?

wrightwing · by **wrightwing** » 26 Apr 2017, 17:57

rhoads56 wrote:
wrightwing wrote:M2 isn't the limit for durability.

I figured it wasn't. Can you elaborate any further?

The F-22 is easily capable of exceeding its design limits (i.e. it's theoretical max speed isn't thrust limited.) I can't give the exact speed, which results in damage, but I will say that it's not typically a result of speeds within its design limits. It's especially key at lower altitudes. Pilots have to throttle back, to avoid overspeeding the jet.

rhoads56 · by **rhoads56** » 27 Apr 2017, 01:53

wrightwing wrote:
rhoads56 wrote:
wrightwing wrote:M2 isn't the limit for durability.

I figured it wasn't. Can you elaborate any further?

The F-22 is easily capable of exceeding its design limits (i.e. it's theoretical max speed isn't thrust limited.) I can't give the exact speed, which results in damage, but I will say that it's not typically a result of speeds within its design limits. It's especially key at lower altitudes. Pilots have to throttle back, to avoid overspeeding the jet.

Fair enough. Thanks for the input - awhile ago TC and scorpion1alpha mentioned that the F-22 actually has a higher top speed than the F-15...Can I get a third on that?

sprstdlyscottsmn · by **sprstdlyscottsmn** » 27 Apr 2017, 02:32

The only reason it wouldn't would be the fixed inlet choking the engine above mach 2.XX

wrightwing · by **wrightwing** » 27 Apr 2017, 03:05

rhoads56 wrote:

Fair enough. Thanks for the input - awhile ago TC and scorpion1alpha mentioned that the F-22 actually has a higher top speed than the F-15...Can I get a third on that?

A reliable source said that it's 1600+ mph, some years ago. I doubt that it would be going anywhere near that, though, as it would significantly affect the range.

mixelflick · by **mixelflick** » 27 Apr 2017, 18:19

At one point early on in testing, I recall reading a "red air" pilot discussing speed. Said something to the effect "we haven't seen closing speeds like this since the Foxbat/Foxhound..".

Make of that what you will. I took it to mean mach 2+, as the Foxbat/Foxhound are the only aircraft I can recall reading about reaching those speeds, particularly while loaded... Mach 1.6 was cited by an Iranian F-14 pilot, while pursing a Mig-25 flying at mach 2.3. The Eagle... most I recall reading about was mach 1.2 in Desert Storm, maybe mach 1.4 but nothing beyond that...

arian · by **arian** » 28 Apr 2017, 00:52

popcorn wrote:There used to be a pic of a F-22 on the web with the skin ablated off it's nose and smeared all over the canopy after apparently exceeding the speed limit. Not good.

Any picture of this? Wouldn't that be an issue with all aircraft and paints?

popcorn · by **popcorn** » 28 Apr 2017, 02:47

arian wrote:
popcorn wrote:There used to be a pic of a F-22 on the web with the skin ablated off it's nose and smeared all over the canopy after apparently exceeding the speed limit. Not good.

Any picture of this? Wouldn't that be an issue with all aircraft and paints?

Sorry, the pic can no longer be found on the web AFAIK. It was from years back. IIRC within a couple of years after IOC. A lot of material had peeled off the nose and the canopy looked like it had been sandblasted.

disconnectedradical · by **disconnectedradical** » 29 Apr 2017, 23:24

wrightwing wrote:
rhoads56 wrote:

Fair enough. Thanks for the input - awhile ago TC and scorpion1alpha mentioned that the F-22 actually has a higher top speed than the F-15...Can I get a third on that?

A reliable source said that it's 1600+ mph, some years ago. I doubt that it would be going anywhere near that, though, as it would significantly affect the range.

I would like something more substantial than this. So far the 1600 mph figure allegedly comes from a quote from test pilot Paul Metz a TV documentary, but digging on Youtube has given no results, and this is currently second hand. I'm not saying it's not possible, but I prefer to have evidence that's more solid. If anyone can dig up the source or the original documentary it would be great.

sferrin · by **sferrin** » 29 Apr 2017, 23:34

disconnectedradical wrote:
wrightwing wrote:
rhoads56 wrote:

Fair enough. Thanks for the input - awhile ago TC and scorpion1alpha mentioned that the F-22 actually has a higher top speed than the F-15...Can I get a third on that?

A reliable source said that it's 1600+ mph, some years ago. I doubt that it would be going anywhere near that, though, as it would significantly affect the range.

I would like something more substantial than this. So far the 1600 mph figure allegedly comes from a quote from test pilot Paul Metz a TV documentary, but digging on Youtube has given no results, and this is currently second hand. I'm not saying it's not possible, but I prefer to have evidence that's more solid. If anyone can dig up the source or the original documentary it would be great.

It was almost certainly me. I was watching a show on the Discovery/History/TLC channel years ago. They were interviewing Paul Metz. In it they asked him how fast the F-22 was. He said, "It's fast. I mean it's REALLY fast. The top speed is classified but it'll do 1600 miles per hour." Tried finding the specific show several times over the years with no luck.