Magoodotcom said:
My understanding is the F-22's top speed is restricted compared to other types due to restricted intake airflow and the need to preserve the 'special' coatings...it's the mid-range transonic to M1.5 region where it excels.


There are thermal and dynamic pressure limits for several different areas - not just for topcoat but structure as well. Some areas, when exposed to certain temperatures for certain periods, right becomes left and up becomes down - which can be a real bummer. This affects some pointy, important areas in particular, and when these things happen you're going into the fight blind.


There are some photos out there of outer surface and topcoat erosion. You can draw your own conclusions from some of those.
 
AFAIR, there were reports from RAF BAC Lightning pilots of exceeding their low level Mach limitations (heat on inlet spike)
both in 'hot pursuit' NATO war games ops - running down Starfighters & Tornados at nought feet..
& later when they were cleared to 'use-up' the remaining Lightning op-flight time just prior to retirement,
.. they still reckoned that if the they had the juice available, they'd whip anything - WFO - on the deck..

I guess peacetime sensibilities would go out the door.. in a real hot 'needs must-devil drives' scenario for F-22 jocks too..
 
quellish said:
Magoodotcom said:
My understanding is the F-22's top speed is restricted compared to other types due to restricted intake airflow and the need to preserve the 'special' coatings...it's the mid-range transonic to M1.5 region where it excels.


There are thermal and dynamic pressure limits for several different areas - not just for topcoat but structure as well. Some areas, when exposed to certain temperatures for certain periods, right becomes left and up becomes down - which can be a real bummer. This affects some pointy, important areas in particular, and when these things happen you're going into the fight blind.


There are some photos out there of outer surface and topcoat erosion. You can draw your own conclusions from some of those.


I seem to recall reading that the F-111's canopy had a notably short service life when the jet was maxed out on the deck. That's what the countdown timer was for.
 
It would make sense that the F-22 is "capable" of very high speeds at low altitude. Many aircraft are capable of high speeds in that environment, but are q (Dynamic pressure=.5*rho(Air Density)*V^2) limited, as Quellish pointed out. The structure is designed to only handle so much pressure, to keep the weight down. However, the F-22 probably has a higher q limit than most aircraft since it was designed for the supercruise environment. This in and of itself would give the F-22 an advantage down low versus comparable aircraft; The MiG-31 probably being the lone exception, since it's built like a Klingon Battle Cruiser, and I mean that in a good way.
 
GTX said:
Magoodotcom said:
I've heard stories about re-engined F-111Cs doing M1.4 down low and M2.6 at altitude...but some came back with paint ablated from the vertical stab and other areas, and other 'items' missing. GTX?


I have heard similar - was part of the TF30P-108 or TF30P-109 development/acceptance I believe. I can't confirm the exact speeds but I can confirm the damage.


Further to this, I also understand the F-111 in question was able to sustain Mach 1+ at altitude with one engine turned off.
 
GTX said:
GTX said:
Magoodotcom said:
I've heard stories about re-engined F-111Cs doing M1.4 down low and M2.6 at altitude...but some came back with paint ablated from the vertical stab and other areas, and other 'items' missing. GTX?


I have heard similar - was part of the TF30P-108 or TF30P-109 development/acceptance I believe. I can't confirm the exact speeds but I can confirm the damage.


Further to this, I also understand the F-111 in question was able to sustain Mach 1+ at altitude with one engine turned off.

Correct and correct...in idle anyway. A former Nav told me the P108/109 could get a clean jet well past the Mach and stay there without burners...super cruise anyone?
 
As for the raptor i recall an interview with a test pilot during the EMD phase that said at low altitude they had a betty warning for overspeed beause the plane could accelerate very easily past the structural limits.




As for other plane supercruising,a number of planes can go around 1.2 dry if they are clean,the F-16, F-15 and i heard T-38 can do that. However all the "supercruise" relevance is in the speed achieved/Fuel consumption ratio.


For example on F-15 and F-16, at MIL power your fuel consumption is about three times the eco cruise one (around mach 0.75) so you basically go (1.2/0.75=1.6) times faster but eat 3 times more fuel which mean your range is only 0.50% the eco range.
If you take the F-22 with mach 1.82 (i know this is not the eco supercruise but this is the MIL one) and say same 3 times fuel consumption you end up with 80% of your eco range.


This is much more relevant.
 
Magoodotcom said:
GTX said:
GTX said:
Magoodotcom said:
I've heard stories about re-engined F-111Cs doing M1.4 down low and M2.6 at altitude...but some came back with paint ablated from the vertical stab and other areas, and other 'items' missing. GTX?


I have heard similar - was part of the TF30P-108 or TF30P-109 development/acceptance I believe. I can't confirm the exact speeds but I can confirm the damage.


Further to this, I also understand the F-111 in question was able to sustain Mach 1+ at altitude with one engine turned off.

Correct and correct...in idle anyway.


Makes sense - the TF30 having a fairly high bypass ratio means the difference between max. dry and afterburning thrust would be quite considerable, so 1 idle + 1 afterburning would likely retain much of the thrust of a pair at max. dry. The MiG-31 might be able to pull off the same trick (speaking of which, as Sundog indicated the Foxhound is also credited with being a blistering performer even at sea level - 1500km/h is generally quoted).
 
Ogami musashi said:
As for the raptor i recall an interview with a test pilot during the EMD phase that said at low altitude they had a betty warning for overspeed beause the plane could accelerate very easily past the structural limits.




As for other plane supercruising,a number of planes can go around 1.2 dry if they are clean,the F-16, F-15 and i heard T-38 can do that. However all the "supercruise" relevance is in the speed achieved/Fuel consumption ratio.


For example on F-15 and F-16, at MIL power your fuel consumption is about three times the eco cruise one (around mach 0.75) so you basically go (1.2/0.75=1.6) times faster but eat 3 times more fuel which mean your range is only 0.50% the eco range.
If you take the F-22 with mach 1.82 (i know this is not the eco supercruise but this is the MIL one) and say same 3 times fuel consumption you end up with 80% of your eco range.


This is much more relevant.

True, it wouldn't be q, after I thought about it, since velocity is velocity regardless of time spent at it. Look at an F-119 compared to an F-100. It's a monster. Of course, so is the F-35's engine, but the F-119 is optimized for supercruise and the F-22 has a much higher thrust to drag ratio than an F-35.
 
Quick question. Where was the F-22 to house the IRST as per the original plan to equip it with the system?.
 
bring_it_on said:
Quick question. Where was the F-22 to house the IRST as per the original plan to equip it with the system?.

Two most commonly cited locations are under the nose or at the wing roots. Not sure which one it was before it got canceled.
 
RadicalDisconnect said:
bring_it_on said:
Quick question. Where was the F-22 to house the IRST as per the original plan to equip it with the system?.

Two most commonly cited locations are under the nose or at the wing roots. Not sure which one it was before it got canceled.

I had read somewhere that it was going to be at the wing roots as well, wish there was a wind tunnel test photo or something :(
 
1984: dual colour IRST requirement
1987: single colour IRST requirement: dual colour goal (desirable but not required)
1989: IRST made a goal i.e. not required.
I believe the original proposal had provision for wing root IRST, deleted in EMD.
I'm not sure the fuselage model in flateric's pic is more than a test item of a representative aperture i.e. may not be F-22 fuselage shape.
 
Some Raptor vs. Flanker from the Malaysian side.

http://www.nst.com.my/node/7204?m=1

The Royal Malaysian Air Force and

the United States Air Force engage in an air combat exercise called Cope Taufan. Haris Hussain joins the ‘furball’

“FIGHT’s on! Fight’s on!”

‘Mogwai’ immediately picks up his target off the port side. He’s chugging along at a fairly fast clip. Together, the closure speed of both aircraft is nudging north of 900 knots.

As the two fighters merge and pass within an eyelash of each other in a blur of black and grey, Mogwai doesn’t even have time to flinch as he rolls the jet, yanks the control stick back into his gut and reefs his big fighter into an eye-wateringly tight left turn.

G-forces rip into his body and Mogwai sucks in a lungful of oxygen as he cranes his neck to keep his adversary, a United States Air Force Lockheed Martin F-22A Raptor, square in his sights.

He works the throttles and makes constant changes to the engine settings. His eyes are fixed on the target but one eyeball is cocked to the airspeed reading on his heads-up display (HUD). At this turn rate, he’s bleeding off airspeed and energy like they’re going out of style. Dogfighting is all about energy management.

The two jets are in a classic turning fight at 15,000 feet (4.57km) over the air combat range in Grik, Perak. Mogwai and ‘Smegs’, his weapons systems officer (whizzo in RMAF parlance), are flying the Royal Malaysian Air Force’s latest and most capable aircraft, the Sukhoi Su-30MKM Super Flanker multirole fighter.

Outside, the twin nozzles of their thrust-vectoring Lyulka AL-31FP engines crank up at a crazy angle and Mogwai begins to “walk up” the nose of his huge fighter onto the Raptor’s centre fuselage.

Up front, Mogwai eyeballs the Raptor, which is also blessed with thrust-vector control, but only in the pitch plane. The target designator box (TDB) on his HUD is locked onto the stealth fighter. The trick now is for Mogwai to bring the “pipper” or gunsight square inside the TDB before he can squeeze off a shot. In the back seat, Smegs provides a running commentary of the unfolding fight.

“Makan dia! Makan dia, beb! Lagi! Lagi! Lagi!” Smegs yells into the hot mike in his Ulmer oxygen mask. His job is that of part tactician, analysing the threat picture, part cheerleader, pushing his pilot on, and as an extra pair of eyes for Mogwai.

This particular evolution is a 1v1 (one-versus-one) engagement, which calls for the employment of short-range air-to-air missiles or guns. The Raptor is armed with the AIM-9M Sidewinder heat-homer and an internal, six-barrel, Gatling-type 20mm M-61A Vulcan cannon. The Super Flanker is carrying the super-agile Vympel R-73 Archer air-to-air missile and has the 30mm, single-barrel Gsh-301 cannon embedded in the starboard leading edge root extension (LERX).

Launching off from Fightertown RMAF Butterworth, this is the second engagement for the two fighters as part of the biggest air combat exercise in the country. Called Cope Taufan, the joint biennial exercise between the RMAF and the USAF is primarily to enhance bilateral training in a realistic environment, ramp up combined readiness, and improve interoperatability between the two fighting forces. In the first “hop” earlier, the advantage went to the Sukhoi boys. Because both aircraft were still hauling bags of gas, the exercise director gave the go-ahead for another fight.

‘GUNS,GUNS,GUNS!’

The outcome of a dogfight hinges on a number of things — the aircraft’s aerodynamic and engine performance, fuel load, the position of the sun, the individual aircrews’ learning curve and the ability to adapt and react to a fluid and rapidly changing set of circumstances. The advantage enjoyed by one aircrew could be lost and shift over to the adversary in the blink of an eye. A gun track can last only one or two seconds. Miss that shot and you’re toast.

Just as Mogwai is close to getting a gun solution on the Raptor, the USAF pilot rolls his jet level and pitches the nose up in a high-G manoeuvre. Vortices stream from his wing root as moisture is literally squeezed from the air. The American plugs the afterburners on his twin Pratt and Whitney F-119 turbofan engines and his nozzles belch out tongues of blue flame. He goes vertical and grabs sky like a homesick angel.

“Pacak! Pacak! Dia pacak, bai!” screams Smegs, as he instinctively grabs the speed handles on his instrument panel in anticipation of the onslaught of Gs. Pacak, in RMAF fighter lingo, is to go vertical. Mogwai sees the move but he’s nanoseconds too late. The Raptor has so much excess thrust that by the time Mogwai bangs on the throttles and selects Zone 5 on the afterburner, he and Smegs might just as well have been talking to themselves because the Raptor is looong gone...

STEEP LEARNING CURVE

Back on the ground, the RMAF pilots whom Life&Times spoke to said the training and experience they received in the two weeks of Cope Taufan was invaluable.

“The objective of these types of exercises is not to see who wins or loses. It’s more of an opportunity for us to learn new things and expand our mission scenarios and capabilities. It also gives us a chance to validate our procedures,” said a Super Flanker pilot.

Sometimes, they have to make things up as they go along. For instance, fighter pilots use what is called EM or energy manoeuvring charts to figure out how best to tackle an adversary.

“We had EM charts on the F-15s but had nothing on the Raptors, since it is still highly classified. So we had to rely on other sources, go online and even make educated guesses based on the aircraft design to come up with a plan to capitalise on its weaknesses,” added the Sukhoi driver.

“There were a lot of things that we learnt from the Americans. The use of large force employment, planning of strike packages and, overall, how to use our forces effectively were some of the lessons we learnt from Cope Taufan,” added an F/A-18D Hornet pilot with No 18 Squadron, based in Butterworth.

A MiG-29N fighter pilot with the famed Smokey Bandits squadron, home ported in RMAF Kuantan, summed it up best.

“Bro, both sides’ learning curve went right through the roof. On the first day! We both went home with a mutual and healthy respect for each other’s capabilities. And to have these (USAF) guys say that we were s*** hot is the biggest compliment you could give a fighter jock.”

harishussain701@gmail.com

Note: For security reasons, the call signs of the aircrew are fictitious and the engagement is a composite of several dogfights as recounted by RMAF pilots.

Star attractions

THE star attractions for this edition of Cope Taufan were undoubtedly the United States Air Force’s Lockheed Martin F-22A Raptor and the Royal Malaysian Air Force’s Sukhoi Su-30MKM Super Flanker multirole fighter.

For the Americans, the Su-30 is an exotic beast, blessed with immense power and agility.

The Russian type’s nose-pointing ability, thanks to its thrust-vector and fly-by-wire flight control system, is second-to-none.

If there’s one aircraft that can pose a serious threat to the USAF in the air-to-air arena, it would be this baby.

On the flip side, the prospect of going head-to-head with the world’s only fully operational, fifth-generation stealth fighter sent RMAF pilots into a tizzy. Many were itching to go up against this much-vaunted fighter. Although the results of the engagements were classified, it was learnt that several RMAF jet jocks acquitted themselves well against the Raptor.

The F-22As are from the 154th Wing, Joint Base Pearl Harbor-Hickam, Hawaii and are the only Air National Guard unit equipped with the type. They were joined by a number of Boeing F-15C Eagles from the 131st Fighter Squadron, 104th Fighter Wing, Barnes Air National Guard Base, Massachusetts, and other support units.

While RMAF pilots had tangled with the Eagles in previous exercises, Cope Taufan 2014 was the Raptors’ first outing in Southeast Asia.

Cope Taufan is a biennial large force employment exercise designed to improve the US’s and Malaysia’s combined readiness.This year’s edition from June 9-20, collectively involved close to 1,000 personnel.

I do wonder if they applied their special stealth sauce from that Boeing 777 to their Flankers.

EDIT: Some anecdotes on F-22 acceleration. According to Aviation Week January 8, 2007, at 13,000 ft and 250 knots, the F-15C took 20 seconds to accelerate to 450 knots. The F-22 accelerated to 500 knots in the same time. No idea if it's calibrated, indicated, or true, or the fuel levels of the two jets.
 
What I'm curious is how they managed to jack the weight of the plane up so much from the YF-22 stage to the F-22 stage. Last I checked they were over 80,000 pounds!
 
First Immersive F-22 Sims Arrive

1/12/2015

Boeing delivered the first pair of 360-degree high-definition F-22 Raptor simulators to the Air Force, the company announced on Jan. 8. "Boeing has delivered what are probably the most advanced high definition flight simulators I have experienced, and they are going to let our pilots realize training unlike any they’ve had before," said Col. Anthony Genatempo, the F-22 system program director at Wright-Patterson AFB, Ohio, in the release. "That translates directly into mission readiness," he added. Boeing plans to upgrade Air Force's three previously constructed F-22 Mission Training Centers with the Constant Resolution Visual System, in addition to the recently completed fourth, and future fifth center, which is slated for completion this summer, according to the release. F-22 MTC locations include JB Elmendorf-Richardson, Alaska, JB Langley-Eustice, Va., Nellis AFB, Nev., JB Pearl Harbor-Hickam, Hawaii, and Tyndall AFB, Fla.
 
First combat mission in details:


http://www.airforcemag.com/MagazineArchive/Pages/2015/February%202015/With-the-Raptors-Over-Syria.aspx


the supercruise leg was visibly quite long.
 
Ogami musashi said:
First combat mission in details:


http://www.airforcemag.com/MagazineArchive/Pages/2015/February%202015/With-the-Raptors-Over-Syria.aspx


the supercruise leg was visibly quite long.

Very interesting article. The complexity of integrated air operations with only a few aircraft is obviously quite daunting. This is why IMHO the USAF has such a huge advantage, at this time, over potential adversaries. They have had real world combat going on since 2002 and arguably since the first Gulf War.
 
...interesting that UAE (Al Dhafra) is considered as south west asia.
 
Looking at this cutaway of the F-22, I'm not sure if space for the AIRST still exists (assuming that it would be at the wing roots). There doesn't seem to be any available space there.

lockheed-martin-f-22-raptor-cutaway.jpg
 
Is there any reason to think these cutaways are accurate beyond fairly general arrangements? I can't imagine that LM let the artist look at the actual production blueprints. But maybe I'm wrong.
 
Based on what we've seen from their IRST tests on the generic model on the previous page and the drawings on the Northrop production designs for the F-23A and the NATF, and also the F-35, it seems to me the IRST would have been in a chin located "housing" under the nose just behind the radome as well. I suppose they could have gone for more coverage in azimuth by having one located in each wing root, sort of a small lerx with faceted windows. Like a stealthy version of what we saw on the nose of the YF-12A.


I'll go through my ATF book again and see if they mention where the system was to be located, but I don't recall ever reading about where the system would be located on the airframe. I know the GD ATF submission had the RADAR system in the LERX's over the inlets, and the IRST in the nose.
 
http://www.edwards.af.mil/news/story.asp?id=123437656

"You're burning an incredible amount of fuel when you're using the afterburner. It shortens the mission duration...with the Raptor you can go supersonic even at sea level without the afterburners. At design altitudes we are talking 1.6+Mach. This means imparting more energy to the weapons we employ allowing longer engagement ranges."

Huh, I didn't know the F-22 can go supersonic at sea level without AB.
 
VTOLicious said:
...interesting that UAE (Al Dhafra) is considered as south west asia.

Not that weird. It's a fairly common term for anything east of the Suez Canal/Red Sea and the Bosphorus/Dardanelles west to Pakistan. So basically Turkey, Armenia, Azerbaijan, Syria, Lebanon, Israel, Iraq, Iran, and the various Gulf states.
 
Jane's reported in 1997 that the provisions for an IRST were still there.

An IR search and track (IRST) system was part of the original ATF requirement. It was deleted during dem/val, but the Avionics Directorate of the USAF Wright Laboratories has continued its development with Lockheed Martin as the contractor, and space, weight, power and cooling provisions for IRST are still on the aircraft. A low-observable IRST window for the F-22 was tested for stealth and durability last year. IRST is valuable for raid assessment, because of its high angular resolution. It is also useful against tactical ballistic missiles, and it can double as a thermal imaging system for ground attack.

https://www.scribd.com/doc/254885620/F-22-Janes1997
 
OK, the book on the ATF program by Picarillo states that the original design for Dem/Val, the one that was too heavy and never built, had the IRST system in the wing roots. I'm looking for info in the book regarding the location of the IRST on the production version.
 
Sundog said:
OK, the book on the ATF program by Picarillo states that the original design for Dem/Val, the one that was too heavy and never built, had the IRST system in the wing roots. I'm looking for info in the book regarding the location of the IRST on the production version.

I'm reading it as well :) (third time). Haven't read it for some time. But I also noticed that Lockheed originally planned to have it in the wing roots. I think Janes pretty much provides a definitive account in the late 90's of what the situation was/is with the IRST.
 
bring_it_on said:
I'm reading it as well :) (third time). Haven't read it for some time. But I also noticed that Lockheed originally planned to have it in the wing roots. I think Janes pretty much provides a definitive account in the late 90's of what the situation was/is with the IRST.


Oh, yeah, I haven't any doubt they made room for the system in the production version. I'm just trying to figure out if they also planned for it to be in the wing roots on the production version or under the nose. Also, until reading this book, I had never realized the biggest weight penalty for the thrust reverser was due to the cooling requirements. I had thought it was just due to the weight of the reverser itself.
 
Do you have any more information on the General Electric IRST that was being tested onboard the Lockheed test bed (Boeing 757) ( Page 116)?
 
F-22s escorted Jordanian fighters for airstrikes in Syria. As well as the F-16s they were also accompanied by an unmanned drone.

http://www.airforcetimes.com/story/military/pentagon/2015/02/06/raptors-escort-jordanian-fighters-syria-airstrikes/22982311/
 
A recent Langley Research Center colloqium with Major Heath, USAF on F-22 capabilities.


A video of the lecture is avaible however i can't connect to it, wonder if it's a country restriction or what.


I someone that succeed in watching it be kind enough to forward it to me, thanks :)


http://colloqsigma.larc.nasa.gov/past-colloquium-lectures/all-colloquium-lectures/colloquium-february-3-2015/
 
Its not a country restriction. Give it a few days, they'll fix it :)

Until then I can give you this ;)

https://www.youtube.com/watch?v=m5Z_Eg5QFbM


Edit - I checked with Michael Holloway, the video is only available form inside NASA Langley firewall..
 
Grey Havoc said:
bring_it_on said:
Its not a country restriction. Give it a few days, they'll fix it :)

Video is working now.

I'm still not getting it to either play or download. I contacted the person in charge and he said its only available for those within the NASA Langley firewall. If it works for you, could you please download it and post it up for us to download.
 
Grey Havoc said:
Sorry, I thought you were referring to the video above. :-[

Ahh..No problem. I think the video could eventually be released through their youtube channel.
 
http://www.ijrame.com/vol2issue1/V2i105.pdf

Some interesting observations here. I was always under the presumption that stealth was about shape, shape, shape, and RAM. This article seems to suggest that RAM is responsible for a good part of the F-22's low RCS. That said, the model used in this simulation may have questionable accuracy. Perhaps more knowledgeable people here can chime in?
 
one can do only so much with shape. while i do believe shape was far more important in the past, with f22 and later projects i do suspect materials play an ever increasing role, perhaps even more than half the rcs reduction for certain wavelengths.
 
RadicalDisconnect said:
I was always under the presumption that stealth was about shape, shape, shape, and RAM.

That makes it sound like the RAM is something simple, when it is more like waveguides with quantum physics levels of engineering....
 

Similar threads

Please donate to support the forum.

Back
Top Bottom