Full scale reproduction WWII fighter aircraft utilizing carbon fibre composites? 1

[Broncazonk]

Would it be possible to construct exact reproduction WWII aircraft out of composite materials? The structural weights would be much less, and the weight distribution would be dramatically different, and that would impact CG and wing placement, but could all that be worked out?

When Flugwerk built those reproduction FW−190D9's they used an Allison engine instead of a Jumo−213A and the weight difference was over 1,000 pounds so they built incredibly robust (and heavy) engine mounts to get the weight/CG right, but they were using standard aluminum construction like the originals.

The empty weight of a P-51 was 7,635 lbs (3,465 kg) and I'm wondering what would happen if 4,000 pounds was trimmed off an aircraft with the exact same lines.

Bronc

 

[KENAT]

Simplistically, with correct application of ballast to correct the trim it would probably be possible. A lot of work though.

Why and who would pay for it may be good questions.

If you want light weight mustangs you could look at P51 F thru H models.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[berkshire]

Broncazonk
The next question you should be asking is, how many of these do you want to produce.
Whilst it is possible to produce advanced composite aircraft that look like original WW2 aircraft, and companies like "WAR aircraft Replicas " have built 1/2 scale versions of a great many WW2 aircraft using standard composite materials such as wood, fabric and fiberglass. using mold-less construction.
I get the feeling that you would like to use molded construction like the "Cirrus, or Lancair aircraft", or modern carbon fiber sailplanes. Whilst these aircraft can be produced fairly cheaply, compared to say wood, or metal aircraft. There is a tremendous up front cost to produce the required tooling beforehand. So to answer your original question, it can be done, however you may not get the weight savings you expect.
B.E.

You are judged not by what you know, but by what you can do.

 

[Broncazonk]

Thank you KENAT and berkshire for your responses. Mustangs and Spitfires are still fairly numerous, though the lack of Merlin engine parts is becoming a serious problem. Thunderbolts and Lightnings, and Wildcats, Hellcats and Corsairs are fairly scarce. Fying examples of German and Japanese fighter aircraft are very rare. (AFAIK the Flugwerk examples of the Fw190A8 and D9 have been grounded due to structural failures caused by Romanian riveting.) At some point in time, flying and displaying exact reproduction WWII aircraft will make sense in the airshow / sport aircraft market.

Bronc

 

[Surestick]

From the looks of it a PT-6 would fit nicely in most RR Merlin cowls and give similar power figures with less weight and orders of magnitude better reliability.
Air intake and exhaust sizes would have to be different and might ruin the lines somewhat.

Are you familiar with the Thunder Mustang?

 

[Broncazonk]

Yep. Thunder Mustang is .75 scale (with the exception of the wing span which is .65). It's an amazing example of what can be done with carbon fiber and epoxy.

Bronc

 

[WKTaylor]

Beware...

The 'sexy fighters' of WWII were inevitibly Heavy-weight tail draggers [US: P-40, P-47, P-51, F-4, F4U, F-6, etc]... while the somewhate less sexy fighters were tricycle landing Gear acft [US: P-38, P-39, P-61, P-63, F-7].

A vast majority of the heavy tail draggers from that era experienced serious take-off and landing mishaps... and lots of crews were killed and injured... along with the aircraft being substantially damaged or destroyed.

Duplicating these high performance acft with lightweight structures/powerplant technologies will lead to the inevitable high mishap rate 'on wheels'.

The ONLY factor that might be a bright spot is that if modern active control systems can be integrated into these acft, to the point the acft will almost takeoff-fly-land itself in a gusting cross-wind... and powerplants become rock-steady-reliable... then they might become safe-enough for modern pilots to own/fly [with a forgiving/trusting spouse]... assuming plenty of $$$S and a serious training/orientation course.

NOTE.
IF You make a P-39 [or P-64] replica, then que-me-up!

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true.
o For those who believe, no proof is required; for those who cannot believe, no proof is possible.
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion"]
o Learn the rules like a pro, so you can break them like an artist. [Picasso]

 

[berkshire]

Wk Taylor.
You then have to consider that the FAA does not like aircraft with engines behind the pilot, where they can come through and get you in a crash.
B.E.

You are judged not by what you know, but by what you can do.

 

[WKTaylor]

berkshire...

In my humble opinion these were the most beeeuuutiful and sleek aircraft of WWII compared with most of the other designs. OK, I'm prejudice: my dad flew -39s early in WWII down in Panama, guarding the canal-zone...about 6-months... and survived with some interesting stories. Later shipped-off to the CBI and back to P-40s for combat [25th and 80FS].

The Bell acft [P-39, P-63] did have that miserable engine arrangement: however, pilots just didn't worry about it all going-to h*ll... thats why they were issued first class parachutes... and 'flight pay' was so high.

I'll bet that an up-front PT-6 turbine installation would work well in a composite airframe version of the -39 or the -63.

I understand both of these were fairly unforgiving in a fully developed spin or snap roll; or or other cross-controlle dmaneuver... but so were a majority of these generation WWII acft. Regardless the Ruskies made good use of them against the Germans... then the Japanese. General toughness and reliability of US acft were likely better than for the Soviet acft, so chances of pilots surving the war were probably better in US equipment.

Amazing... there is a websites dedicated to the P-63.

http://www.p63kingcobra.com/

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true.
o For those who believe, no proof is required; for those who cannot believe, no proof is possible.
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion"]
o Learn the rules like a pro, so you can break them like an artist. [Picasso]

 

[drawoh]

wktaylor,

I thought the P-38 was one of the main sexy aircraft of WWII. I understand that it influenced car design in the 1950s.

Did all the tail draggers have landing and take-off problems, or just some of them? P-40s ground looped rather easily. Messerschmidt Bf-109s had fragile landing gear. Spitfires and Corsairs had long noses and narrow landing gear compared to Hurricanes and Hellcats respectively. The Spitfire's narrow landing gear was marginal, and it became less than marginal when they converted them to carrier landing Seafires.

YouTube has a bunch of US military films on flying Hellcats, Corsairs, Warhawks and such. I was somewhat surprised to learn that landing speed on a Hellcat was something like 55mph[ ](knots). For the Corsair, this was around 65mph and the Warhawk, around 75mph. This makes sense. A P-40 gets a heck of a lot more runway. My book on Seafires states that Hellcats and Corsairs could easily out-turn a Seafire[ ]LFIII. The Seafire's wing loading would have helped to make landings exciting.

About a third of the pictures in my Seafire book are of crash landings on carriers. My understanding is that the US Navy systemically filmed each and every landing performed during WWII. I would assume the Royal Navy did something similar. This would have created libraries of interesting pictures.

Most WWII pilots were in their early twenties, with maybe hundreds of hours of flying time. They were flying their aircraft, particularly fighters, aggressively. Crashes are inevitable. Read up on Steve Wozniak crashing his Beechcraft Bonanza. They concluded that he was not qualified to fly planes of that level of performance. Let's change the Bonanza to a Griffon engined Spitfire!

If you like P-39s, read up on Alexander Pokryshkin. This WWII Soviet air ace made extensive use of the P-39. Combat on the Russian front took place mostly at low altitude, where the P-39's Allison V1710 engine was effective.

--
JHG

 

[MultiVar]

Actually, the Swiss have already certificated and put into line production the aircraft that you
are proposing... it's called the Pilatus PC-21... I'll take TWO!

 

[Broncazonk]

The project would entail the creation of EXACT exterior reproductions of famous WWII fighter aircraft for airshow, static display and TV/film production. Said aircraft are required to be aerobatic capable. Provisionally: all originally water cooled engine aircraft will incorporate the Allison V-1710, the air cooled radials will be powered by the Wright R-1820-86.

 

[drawoh]

Broncazonk,

Canadian Warplane Heritage has a very accurate looking, full sized, plastic reproduction of a Hawker Hurricane at Hamilton, Ontario. The thing is not flyable, making fabrication a lot easier.

--
JHG

 

[Surestick]

Quote wktaylor: "
The Bell acft [P-39, P-63] did have that miserable engine arrangement: however, pilots just didn't worry about it all going-to h*ll... thats why they were issued first class parachutes... and 'flight pay' was so high"

I suspect they did worry about it a lot, and flew their missions anyway.

I think worrying about the safety of a WWII fighter reproduction is a bit silly. If you built them the cost would be prohibitive enough that only a select few, with proper training, could afford to own/fly them. They could afford to own/fly an original WWII fighter which would be just as dangerous.

If you do find a way to do it affordably sign me up for a De Havilland Mosquito.

 

[drawoh]

Surestick,

Somebody in New Zealand is building Mosquitos. Maybe someone will start building Merlins again.

As I noted above, a Beechcraft Bonanza is a high performance aircraft. WWII combat craft were that much hairier, making them tricky to fly with or without dragging tails. Maybe what you want is a Hawker Hurricane or a Grumman Hellcat.

--
JHG

 

[MikeHalloran]

Several decades back, we saw a Hawker Sea Fury make a low pass with smoke trailing to demonstrate the persistence of tip vortices. I swear they were still visible after 20 minutes. But the thing I remember most fondly is the sound that airplane made.



Mike Halloran
Pembroke Pines, FL, USA

 

[berkshire]

Mike,
The Sea Fury was one of the last piston engine fighters, but that engine was no Merlin, it was fitted with a Bristol Centaurus 18 cylinder radial engine developing over 3000 horsepower. None the less a ground shaking sound at low altitudes.
B.E.

You are judged not by what you know, but by what you can do.

 

[aerostructurejoe]

but doen't the weight affect the airworthiness of the airplane? because a plane will be more susceptible to air currents, but it depents right... well probably it is theoretically possible, but is going to be hard.

 

[crackman]

broncazonk

I would agree with wktaylor strongly. It certainly would be possible to create a replica using composites but one would need to very carefully research and understand the original design and the substantiation and validation of the original airframe. In particular, since these were high performance aircraft, one key item to keep in mind is the stiffness of the airframe and how replacing the structure with composites might impact this. For example, many people are not aware that the F4U corsair had numerous accidents due to fatigue related failures in the empennage due to buffet during dives. Several redesigns and full scale tests were performed in order to try to fix this problem. If the empennage was replaced with a composite one, how would this fare? Most of the other aircraft during ww2 had similar type events related to various other parts of the airframe. This is one of the reasons that the aircraft went thru so many model changes. I would venture most people today do not know all of the reasons why or how a WW2 model D of an aircraft type was redesigned to a model F. Without understanding these issues, it would be difficult to redesign with composites without going thru and expensive test program.

However, I do believe cost efficient replicas could be made using more modern and cost effective manufacturing practices which were not available at the time while maintaining the same design capabilities. Again, though, one needs to know what "they don't know" in order to accomplish this and so "research" is paramount. If the original data is available (which in many cases it is albeit difficult to locate), many of the metallic designs could be vastly improved and simplified since machining costs today are very reasonable. Remember, machining during ww2 was a very costly process and the availability of certain metals was cost prohibitive. As a result, many of these original structural designs would be considered too labor intensive today. However, machining today is very affordable and vastly improved materials are readily available.

As a final comment, see the following link for a complete restoration/replacement (utilizing modern technology) of a constellation:

http://www.lufthansa-technik.com/super-star

good luck