mattWow, just wow. I’m surprised nobody has advocated the trench strafing biplanes from WWI.
Composite based Sopwith Camel with a vankel engine or something?
hmm ok i buy that just for the novelty factor.
What was that russian propfan ground attack aircraft there was a model made, i think it was by meschieve but i am not sure.
mattIrony is that a commercial aircraft has the highest percentage of composite uses. The Boeing 787 Dreamliner is made up of 50% composite by weight, or 80% composite by volume.
Different requirements though, and the 787 is struggling and i am not sure if Boeing have sorted out the issue of wrinkles
having more composites isnt always a good thing.
mattWhat happened to the OV-10 NOGS? was it cancelled? Looks like a modern version of a miniturised lancaster.. :S
was it/is it a good flyer?
Out of all the contendors the ability to drop airborn troops at any given place or for nigh ops looks to be very useful for COIN ops.
I know of one other country could find the NOGS very useful.
Can the NOGS be interchanged with the normal version for troop carying?
mattFirst, what’s wrong with the A-10?
These armed agriculture planes are just good to shoot up folks who don’t shoot back.
And I’d take a re-interpretation of the NOGS Bronco with FLIR, a 30mm chain gun belly turret, and two pods with Laser Zunis or Hellfires over an AT-6 or other prop trainer any day.
Is the production line and supply chain for the A-10 still going?
As for not being able to control the types of weapons the enemy has and the taliban being able to get hold of stingers and sams and things.. well surely the danger exists the same for the MV-22 and Apache and Cobra and other slow or rotor craft?
mattI think you are overrating your “z pins” there, matt.
Is not dealing with the main composites problem, the resin, is the resin the one that cracks, no the fibers.
Actually, the trend is to produce smaller fibers (the nanotubes thingy) to be more homogeneous with the resin, they key for composites is there, the z pins is more like a patch solution for the nowdays capability, and i don’t think is that critical.
Remember, the F22 program was meant to have 50% of composites, which was cut down to 25%
About indians, i don’t know, i can tell why the g-loads goals were decreased, why only 6gs were achieved on tests, probably is money probably is technology, probably the designers were way to optimists, i can tell.
Probably all of the above, having 45% by weight or volume of composites means nothing if your aircraft structure cant clear more than 6g’s. That was news to me by the way i thought the tejas was cleared for 7g’s
As for using either SWNT (single wall nanotubes) or MWNT (multiwall nano tubes) to increase fracture toughness of epoxides well i have not seen any proper evidence, maybe in a few years time but it looks likely that nano tubes could go the way of asbestos fibres.
its good to use the word nano for a marketing gimic and thats about all. or if you are a university trying to get some poor saps money.
I would not trust half the papers that are published about nano tubes and practicability.
mattOh, it is special beast, all right. This is why they built only 187. 😉
Either way, it doesn’t matter. One would have to cool the airframe down to environmental temperature to mask it’s IIR signature (short of hiding in clouds). At tropopause it’s -56°C and I don’t think that F22 even in free fall can do that. Call me skeptic, though. 😀
Ill ignore your first comment un fair and nothing to do with the capability of the aircraft.
as for the second comment fair play to you and good point!
mattWasn’t that ~180,000$ damage when fire dpt. pulled that guy out of the F22’s cockpit, using saws?
How much of the $180,000 damage was due to sub systems damage in the aircraft or damage to say the wings etc?
we do not know enough to be honest.
Lets be fair, the F-22 is a special beast so it cant do mach 3.2 due to its canopy or what not, but does it matter when it can do all the rest?
As for stagnation temperatures, ill have to bow out on this one, i can not remember what kind of temperatures to expect at those points, i remember it being not so much but aero is something i have not touched in eons..and eons..
I do remember that even for engine inlets the rise between p1 – p2 and T1- T2 is not that great a deal.
mattOf course it’s not just “open source” info on how composites were used in F-22 specifically – the entire industry has moved forward on this, civil aviation included, and indeed India’s experience with Tejas has give it much experience here that PAF-FA will only build on top of. Correct me if I’m wrong, but Tejas may have a higher % of composites than F-22, which isn’t surprising given the advantage of time. Further, it isn’t so much a manner of “transferring” this technology from Russia, as much as the joint project funding local industries to develop their capabilities towards a concrete product.
That could be (90% chance) a pretty inaccurate and brazen statement.
There is knowledge and know how behind the F-22 structure and its manufacture that would take just as much time now to develope as it took back then. I wouldnt be so dismissive.
The % of composite by weight on the Tejas is no use to anyone. and Tejas was all well and good for Indian industry but its only got it to catch up. mind you that is based on snippets from news, but i doubt they are world leading.
A large part of the aerospace industry was working on the co-cured co bonded structures back in the 80’s and 90s when Tejas was just starting out. Dont get me wrong Tejas is a great achievement but to compare it to the F-22 just seems naive.
Fair dues to the research team of Tejas they have done well but they could always learn more.
F-22 probably uses systems (fibres and matrix) that the tejas team could only dream off.
ill ignore all the computery bit not my strong point bores me too much so i have never been able to finish an article on it.. too many abbriviations and what nots.
mattAs for weight, I don’t know, but somehow I doubt that this is an issue, since F22 has ~20t empty, already.
Stealth is a matter of shaping and conductivity and hasn’t much to do with plastics (insulator), which is claimed being the weakest link.
This whole story is somehow oddly constructed. It doesn’t fit.
The use of the fuel is pretty much genius for the F-22 correct me if i am wrong but I do not think it has any heavy or expensive de-icing or anti icing gizmos.
or maybe you do not fully understand it or now everything about the F-22 or its manufacture or ever that you do not know everything about stealth could it be possible too?
Weight would be an issue, polycarbonate sounds a lot lighter to me than say glass.
polycarbonate Density 0.950 – 1.54 g/cc 0.0343 – 0.0556 lb/in³ Average value: 1.20 g/cc Grade Count:391
Borosilacate glass Density 2.40 g/cc 0.0867 lb/in³
Aremco AREMCOLOXâ„¢ 502-400 Machinable Glass Ceramic Specific Gravity 3.00 g/cc 3.00 g/cc
mattThe ‘problem’ is fatigue. The canopy is ‘certified’ for a 400 flight hours of life (under ‘normal/intended’ operating conditions). Any period of time at higher than ‘normal/intended’ operating conditions (such as excessive speed) reduces this time, causing the canopy to have to be replaced sooner than otherwise (& they aren’t exaclty cheap).
How much are the canopies?
mattNo, not really.
IRST scans much wider temperature band than, what is cooling system able too cool the aircraft down.
However, if an F22 would, by some miracle be able to avoid IR detection of itself, the temperature of stagnation point in front of the aircraft would, in fact discover it’s presence.
So no, you can’t really hide 20t of metal from IR system, that easy.
Do you know what the capabilities of the cooling system are? Do you have the range versus differential temperature figures of the IRST to say what can be detected when? Sounds like a pretty wide an inaccurate statement.
The comments seem very ambugious and disingenious.
But that is why the coolent is pumped around the craft why how else would you have heat?
If the F22 is able to avoid detection by IR surely that means they have over come issues of stagnation temperatures?
Also i would hazard a guess that the F-22 is 20tons of composite not metal (lol ok thats a lie not all of it is composite i know)..
mattWell Mig-25’s got to M3.2, so that should suffice for F22, too.
The trouble with picture clarity and thermal liability at >= ~110°C is that such material is soft and it’s perfect clarity will most probably be ruined during first harder run. So, there isn’t much point in insisting on something that can get ruined in one flight.
Finally, F22’s combat mission profile and avionics, requires the least clear vision of (almost?) all fighters in US inventory.Sure, how many other planes you saw that cool their skin?
Erm i know many aircraft that warm their skins.. especially leading edge D noses.
What is the weight of those canopies on the mig 25? also what radar signatures do those mig 25 canopies have?
Would be interesting to see the numbers, i would envisage that the mig 25 canopy does not have the same stealth requirements.
mattWell i think the MOD has realised that keeping the defense industry in the UK going is good all around not only does it give you a strategic leg up but also it helps the economy.
Defense is the only manufacturing sector outside of automotive worth much these days.
mattAs stated before the ‘weak link’ is the canopy – and not so much an immediate failure in flight but rather a reduction in flight hours of life.
Thing is there are certain inaliable laws of physics and certain materials which maybe good for providing stealth may not do so well to survive high speed impact!
Any item flying that fast bombarded with small particles would have a problem.
Is the problem with the canopy that the stealth is so reduced that the F-22 isnt the size of a golf ball anymore, or is it that the canopy is fatigued and damaged?
if its the first than surely it is a question of user requirements bein too high..
mattAnd why is it cooled, if the temperature is in check? 😀
Erm maybe it is in check because it is cooled? logical isnt it?
Simples!
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