USAF T-X - here we go again
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USAF T-X - here we go again
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......
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......
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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.
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.
Do a Hover - it avoids G
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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.
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.
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.
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.
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........
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........
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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.....
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.....
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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.
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.
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.
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I'm not sure why the USAF need it -nobody else needs that type of capability in a trainer
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.
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+.
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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.................
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.................
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.
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.
Do a Hover - it avoids G
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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.
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.
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.
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.
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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.
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.
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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
Damn, been retired for two years, but it still catches up with me. :-)
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
Damn, been retired for two years, but it still catches up with me. :-)
