USAF T-X - here we go again

[Heathrow Harry]

According to this week's "Flight" some of the minimum requirements are so strict they have already knocked out most current types

e.g they require sustained g of 6.5g minimum and 7.5 g is a target

Bet this leads to a new (or heavily reworked design) winning = cost overruns, delayed in-service dates and a lot fewer airframes than they really need.

This sort of thing reminds me of the A-12A Avenger were all sorts of "minimums" were required, seemingly each one written in as "stretch targets" by every man and his dog in the Pentagon.

the plane never came into service but if they'd all been willing to accept something a little less cutting edge they'd have had their strike plane 20 years ago......

[Martin the Martian]

If I was conspiracy minded I would say it was an effort to knock out any foreign designs from the competition. But I'm not, so I'll just say that it is an incredibly stringent requirement.

I'm not sure why the USAF need it -nobody else needs that type of capability in a trainer- but it looks like they have failed to learn their lesson about overcomplicating matters. They will end up funding an entirely new aircraft that will be way over the top for an advanced trainer and will be eventually cancelled as being too expensive. The T-38s will require another SLEP and then they'll start the whole shebang again.

Why not just pick one of the existing products, guys? They are all perfectly adequate and able to do the job required of them.

[John Farley]

Modern aerodynamics and engines enable aircraft to be designed with such sustained performance that the pilot is becoming the limiting factor in how they are used. I suspect that the USAF are looking for a vehicle where they can train (and chop) pilots to handle their bodies as well as learning how to fly the aeroplane.

If you doubt the importance of this (which was not a problem for earlier generation pilots) then read the accident report on the F-22 that was lost checking its high g handling at Edwards. The new trainer will be around for 50-60 years from now after which the whole unmanned business will have become the established norm. This trainer has to bridge the gap from now until then.

[Courtney Mil]

John, I'm interested in your comment about the pilot becoming the limiting factor, especially with reference to F-22 - I think, physiologically he has been for years. Raptor has the same Gz limit as F-15, in which we were training our students to operate at +9g, using the centrifuge to do the g-tolerance training and individual assessment way back. I would agree that a trainer that offers exposure to higher g earlier in training is a good thing, but it starts to get expensive to make the airframe capable of withstanding the forces and increased fatigue usage and to make the engine powerful enough to sustain the higher g. Getting the fighters to operate above those sort of levels becomes even more technically difficult, although technology moves on, obviously. That makes me wonder if that problem (pilot being limiting factor with respect to g) will continue to become much more of an issue. Of course the French managed to stress Mirage to 11g, but I don't think the airframe started life with many coins that high!

If memory serves, the pilot in the Edwards crash ejected, but died from blast injuries due to the speed, which was well above the ACES seat limit. My understanding was that he had not performed his g-straining manoeuvre (insert your own term for that here). So with regard to those two aspects, the pilot and the seat were the limiting factors, as you say.

Still, shouldn't be a problem for F-35 drivers - tongue firmly in cheek, by the way.:E

[Haraka]

Again tongue in cheek.
As your natural 'g' tolerance goes up as you get older ( 'cos yer arteries harden etc.), perhaps we should look to older pilots, whose cunning and experience outweighs their slower reactions..........


"Space Cowboys", step on down........:)

[Heathrow Harry]

personally i'd be a bit surprised if the T-X isn't pretty much a US design - it's a big order and years and years of maintenance and upgrades in it - far better than few tankers TBH

It's just they're going to write a spec that will lead to all sorts of grief when if they were willing to compromise at 90% of the wish list they'd have something in place on cost and on time.....

[ShotOne]

Not so bothered how the US plays it. Their order is at least likely to be large enough to justify a bespoke product...but that's unlikely to be the case for any future UK order. But we'll insist on doing it that way anyway., rather than just buy something that exists already. And every department will add some extra requirements until it costs so much we can only afford to buy one.

[sandiego89]

While I share the concerns about capability creep, it does make sense to have a trainer that can take the student more into the advanced stages, instead of having them do much of their continuation training on front line (and very expensive) aircraft. Yes you will still have to have type/transition training, but perhaps less of it.

And while the "Red Air" emulator that was linked to the program does not seem to be the current driver, I imagine the thought is still there and helped nudge the requirments up- better to build it in early.

[Pontius Navigator]

Remember Jaguar was ordered as a supersonic trainer.

[KenV]

I'm not sure why the USAF need it -nobody else needs that type of capability in a trainerMay I offer my two cent's worth:

Penny #1: That level of performance is almost certainly not needed for undergraduate pilot training. However, the same trainer will be used for refresher training of pilots who fly the F-22 and whatever future air superiority fighters may come along. It's really expensive to operate front line fighters and a high performance trainer can provide a big percentage of the refresher training needed to keep the pilots current in those fighters. Further, the T-X will very likely form the basis for the "red-air aggressor aircraft." That's the aircraft that will be used to simulate 5th (and maybe 6th) generation opponent aircraft. As such, it will need exceptional performance.

Penny #2: The 6.5G sustained turn requirement can be met by several existing trainers. However, most cannot meet that sustained turn performance at the altitudes USAF wants to train its pilots. So its not so much the raw turn performance that's proving difficult, but doing it at the altitude USAF demands. USAF apparently wants to do the high G stuff at higher altitudes to provide a greater margin of safety to the pilots being trained.

Hope this was helpful.

[Courtney Mil]

Yes, it was. And makes perfect sense. And 6.5g isn't that tall an order in airframe terms - similar kind of loading the Hawk et al. I was imagining they were talking 7.5+.

[Heathrow Harry]

the full g requirement is in "Flight"

I can see the reasons but doesn't anyone look at recent procurement issues and say

"This is what we can afford for x hundred trainers, this is what the constructors can REALLY achieve without going crazy - let's design for that?"

it's only a trainer after all - not a B-52/B-1 replacement.................

[LowObservable]

PN - Indeed it was - AST.362 was a Gnat/Hunter T7 replacement. Mainly, I suspect, a trainer for TSR.2.

Generally: this trend in T-X reflects the high cost per flight hour of the F-22 and F-35, plus the fact that there are no two-seaters. Clearly one does not want to find out that a pilot is susceptible to high g levels and rapid onset when that individual is alone in an aircraft.

The high cost favors what is called "downloading" or transferring training tasks to a less costly aircraft. A higher-performance trainer does more of this; and since it's an economic case too, if the CPFH on the fighter is high, the economic case will close at a higher CPFH for the trainer.

Also, in addition to undergraduate pilot training (which is what T-X is primarily for) there is growing interest in putting companion aircraft into the operational unit. (ACC resisted this, but now has T-38s on F-22 squadrons.) Budget documents show that this is expressly being taken into account as an adjunct to the T-X program.

What will be interesting is to see what Boeing/Saab and NG propose as clean-sheet designs.

By the way, the Italians are insistent that the requirement does not cut out the M346 - but there's no sign of a partner willing to take them to the dance.

[John Farley]

Courtney

I find it very difficult to be certain wot will happen in the future (unlike some posters) but I do feel it is sustained g capability (not simple g limits) which are gradually making pilots have to waste some performance available from their mounts. Plus that trend is increasing.

Re the Edwards accident listening to the voice recording of how hard the pilot found some of the earlier points impressed me with how difficult life is getting. But I fully accept the final accident point was about something else.

[Willard Whyte]

A manoeuvrable little trainer with a couple of AIM-9X and a gun pod would make a nice 'n' cheap lightweight point-defence fighter...

[Plastic Bonsai]

http://i538.photobucket.com/albums/ff347/Plastic_Bonsai/redarrer_zpsdfa5ahtg.jpg (http://s538.photobucket.com/user/Plastic_Bonsai/media/redarrer_zpsdfa5ahtg.jpg.html)

Also available in black...

[Stuff]

The drag index on that will be horrible!

I took the static display from Valley to RIAT many moons ago and, even though I'd done the calculation, was impressed at the rate the fuel disappeared when you put fins on the 'winders.

[KenV]

The following may be of interest to those with "requirements growth/creep" concerns:

Air Force Secretary Deborah Lee James announced in January that T-X will be a pathfinder for her Bending the Cost Curve initiative, which is designed to allow for dialog with industry on requirements and cost trades with a goal of reducing weapon-system cycle time and cost. “When it comes to T-X, we are about two years away from a request for proposals stage, and this new process should allow us to directly engage industry as we develop an understanding of how to best evaluate our objective and our threshold requirements,” James said. Today’s procurement process is linear, with requirements developed by one unit and handed over to another for a development and buy. James hopes that by opening a dialog with industry early in the process, the service can tailor the requirements not only for operational needs but with a realistic budget in mind.

[Cpt_Pugwash]

ShotOne,
Cost growth and requirements creep is not exactly a new concept, David Kirkpatrick and Philip Pugh were writing about it in 1985.
Towards the Starship Enterprise (http://www.tandfonline.com/doi/abs/10.1080/08823871.1985.10462343#.Va6fz7WKKGk)

Damn, been retired for two years, but it still catches up with me. :-)

[AtomKraft]

Does anyone have a date for that F-22 accident at Edwards?

There was a heckuva bang while I was there, followed by much smoke.....

[ShotOne]

"Not a new concept..." That's sort of my point, cpt; we have to relearn the lesson with bigger numbers for every procurement project. Yes the Americans probably do so too but with their much bigger production runs it doesn't matter so much. As a result the European NATO nations combined spend very roughly the same cash but get pathetically little to show for it.

[Bastardeux]

I think the musings about downloading training onto cheaper aircraft are most likely on the money; the high requirements aren't for its abilities to train new pilots, but to make it a legitimate replacement for hours on frontline aircraft. Rather like the rumours that the QWI course is going to be carried out on the T2, they'll be used far more extensively than just fast jet trainers...and having heard some of the proposed plans for F35 flying hours, it sounds like the only way to keep people current.

[Martin the Martian]

Many thanks for the explanations, gents. Another thought has popped up, however.

Just how feasible is it to combine an advanced trainer for a pilot who has just stepped out of a T-6 with the requirement for a lightweight, agile aircraft with the performance of a Gripen or F-16 and then put it all in one airframe? We did indeed set out to do the same with the Jaguar, and it is telling that both the UK and France decided to take a different path and leave it as a combat aircraft while designing something else for the training role. Are the USAF likely to find themselves in the same position, or will they be forced to procure two separate types to fulfil what appear to be two very different requirements?

Or, to put it another way, is the T-50 or M346 -or even the T-38- as far as we can go in designing a pure trainer before it becomes something else altogether?

[Bevo]

T-X is also basically a series of impossibilities. Whether it’s the budget, the emergence of clean-sheet proposals and the proliferation of players, or the shifting requirements, pretty much everything about this program makes analysts and observers throw up their hands in despair.

Funding T-X is the biggest apparent impossibility…………………

On the other hand, it’s impossible to not proceed with T-X. Replacing the T-38 (see photo) would seem to be a necessary and time-urgent requirement………………

What makes T-X cancellation or long-term deferral impossible, however, is the T-38 fleet’s growing need……………………………..

T-X requirements are another problem. Right now, it is impossible to determine the ideal T-X trainer, because the requirements have shifted………………………

The biggest T-X impossibility of all, it would seem, would be to get companies to invest their own money in a clean-sheet design……………….

And consider T-X’s importance relative to the broader high-end jet trainer market. Over the past 20 years (1995-2014), just 760 Western high-end jet trainers have been delivered worldwide, a number divided among six different models. T-X procurement, plus additional requirements and exports, will almost certainly result in 500 aircraft being built over the next 20 years or so.

In other words, for any major U.S. airframer and anyone else building a trainer in this class, it is impossible to not compete for this requirement.
http://aviationweek.com/ (http://aviationweek.com/defense/opinion-shifting-requirements-budget-reality-conspiring-against-t-x)

Earlier this year, Northrop Grumman announced it will propose a clean-sheet design for the T-X requirement, departing from its arrangement with BAE Systems to offer the latter company’s Hawk jet trainer, although Northrop Grumman is still teamed with the British company. In March, General Dynamics withdrew from its partnership with Italy’s Alenia Aermacchi to offer the latter’s M-346, quoting business reasons, but Alenia told AIN that it is looking for another U.S. partner. Lockheed Martin and partner Korea Aerospace Industries have proposed the latter’s T-50 trainer.

Boeing and Sweden’s Saab signed a joint development agreement in December 2013 to offer a clean-sheet design. At a media briefing ahead of the Paris Air Show, Jeff Kohler, v-p for international business development with Boeing Military Aircraft, said that Saab brings “some unique skills, and its experience in smaller fighters.”

During a presentation to U.S. exhibitors at the Paris Air Show, Air Force Secretary Deborah Lee James said the requirements that the service released in March are “final.” Asked to elaborate, she described a tiered approach to the requirements with “objective” and “threshold” levels. “Threshold—think of that as the bare minimum requirement—and think of the objective requirement as something that we would like to have, but we very much want to understand the cost-capability tradeoff,” she said. “Once we understand that more, it might be that we’re willing to pay for the objective level [or] maybe not. We consider these to be final requirements…we don’t want to keep changing our minds,” James added.http://www.ainonline.com/ (http://www.ainonline.com/aviation-news/defense/2015-06-18/us-air-forces-t-x-requirements-test-field)

[LowObservable]

MtM - There are limits... although you could program the FBW system like a Corvette's suspension, dialing in anything from "Cruise" to "Racetrack". This is actually done on the Yak-130.

I suspect that trying for Gripen/F-16 performance in a trainer would be a bridge too far, economically speaking. You need a burner = a lot more fuel = bigger airplane. So far there is no sign that T-X is supposed to be supersonic - as far as I can tell there is only one supersonic sortie on the T-38 UPT syllabus today.

If you want a real Aggressor/LIFT type with supersonic speed, you may find it better to go buy some Gripens to do exactly that than to make all 350 UPT birds supersonic-capable. As it is, the T-50 pushes very close to the size/weight of the Gripen D, and will have similar operating costs.

My guess is that the Boeing/Saab demonstrator will have a non-reheated F414 and will be high-subsonic, but with a lower OEW than the T-50.

[Courtney Mil]

AtomKraft, Early 2009. It's easy to find. Give me a moment.

[Courtney Mil]

25 March 2009 according to the accident report.

[Courtney Mil]

Rather like the rumours that the QWI course is going to be carried out on the T2

Which QWI Course? The Hawk one?

[Bob Viking]

Oh no no. Your fears are correct!

BV:E

[O-P]

Good joke Bob, you nearly had me there...wait, you were joking...weren't you?


Anyway, the requirements for this trainer/red air jet seem rather extreme. Here goes my idea, what about a stripped out F-16D with a plug and play front end radar/IRST pack.


The infrastructure to support the jet is already in place, the line is still open, they know how to fly it...I must be missing something?

[Bob Viking]

O-P.

One day we'll know for sure;)

As for the T-X project we may have to throw conventional wisdom out the window. We all have our own opinions and there have probably been umpteen times throughout history where experts (I mean people like us!) have said "it'll never work" and then are proven wrong.

I've lost count of the number of times I've heard someone suggest a cleaned up F16 for a new trainer. I've also lost count of the number of times someone has said it's ridiculous and will never work.

The fact is a decision will be made eventually, for right or wrong, and the guys at the coal face will probably make it work.

Somewhere along the line some men in suits will make a lot of money at the expense of a Government. Of that I am certain.

BV

[O-P]

Bob,


Well said fella.


But it was a joke, right?

[LowObservable]

I ran some basic numbers on a super-stripped F-16 when the requirement was called RAFTS. Not a totally bad idea; remember F-80 to T-33? But times have moved on and LCC rules. GE has even mentioned a new engine.

[Bob Viking]

O-P.

I shall say no more. I'm sufficiently out of the loop that all I can do is add fuel to the speculative fire.

BV

[John Farley]

When trying to decide the spec today for an advanced trainer that will be in use 50+ years time there are clearly lots of what ifs that have to be addressed.

As I indicated earlier, I believe sustained g could be a biggy in the future. So far as the pilot is concerned there is much more to this than a simple macho how long can you grunt for. AvMed docs have told me that once 5-6 is maintained for more than about 30 secs then the body chemistry starts to react and up the blood pressure (clearly a good thing) but the big snag is that if the g is then released quickly (very likely in many if not most circumstances) then the body can overreact and suddenly dump blood pressure to a very low level. Potentially out like a light time.

It all sounds a lot harder than gazing out from a hover.

PS Anybody know of a spec that has included sustained g before this one?

[Courtney Mil]

Yes, John, and so do you. The Harrier needed sustain 1g in the hover! :cool:

[KenV]

PS Anybody know of a spec that has included sustained g before this one?

My understanding is that F-35 has a 4.5G sustained turn requirement. But one must be careful when comparing such a number. Altitude, fuel state, payload, and external stores can all affect sustained turn. Many of the trainers on the market for example can already meet a 6.5G sustained turn requirement. But they cannot meet the T-X's specific requirement which includes fuel state, payload, and altitude. I understand that altitude is what prevents the Hawk and M-346 from being compliant.

[KenV]

USAF has clarified their turn rate requirements for the T-X. Instead of a 6.5 G sustained turn rate (i.e. no loss in airspeed or altitude during a continuous 6.5G turn) the new requirement is for the following:
perform a turning maneuver in which 6.5 g or above is sustained:
through a 140-deg. turn.
starting at 15,000 ft
completing it no lower than 13,000 ft.
losing no more than 10% of its turn entry speed.

The above is a much more benign requirement.
And reportedly, the purpose of this maneuver is to "evaluate and improve the student pilot’s g-resistance with a tactically representative maneuver." To me, this is a clear sign that USAF is listening to industry in formulating requirements for T-X. To put this in perspective, the Aermacchi M-346 reportedly just meets this requirement.

And in related news, Aermacchi says they've lined up a new US partner for their trainer, who will be announced "very soon."