Scale ME-262

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Toobuilder

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The scale factor in the cockpit area is one of the biggest issues. Compounding that, the German cockpits of that era were VERY tight even full scale. You might have to use a semi supine seating with much of your body forward like a modern sailplane with only your head in the canopy area. Engine nacelles are not going to scale well either, but for the opposite reason. These modern model based engines are going to be swimming in the scale nacelle OML. Long tailpipe too.

But for certain, original drawings are going to be practically worthless for structural detail. Cardinal measurements are going to be the only use - it's an entirely new structure beyond that. You'd be better off starting with something like an RV for a sanity check on the structure.

...and to pile on a prior post, I can get you into an L-39 TODAY for less money than this project will cost.

IMG_20190915_143008651.jpg
 
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pictsidhe

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;)

Actually one could also place the battery/batteries up front. Decent chunk of weight there. Plus the heavy cabling that then runs back.



Not sure how useful the drawings would be as, at first glance, I don't see any dimensions. I'd have to make hand measurements, convert to full size then back down to 2/3's. Seems ripe for human error (knowing me).

As for stress engineering I figured I'd have to do it anyways as the weights of the components (e.g. engines) are vastly different, plus, as I mentioned in the OP I would give some thoughts (much further down the road) to composites. There are a lot of curves on this thing. Bending sheet aluminum to obtain them for a one-off plane seems overwhelming.
You would find making an extremely accurate replica extremely difficult. the few % error from measuring some of the best available drawings will be minor compared to the shape compromises you'll need to make for it to work as sub scale homebuilt. For most of mine, I'm measuring the plans, then scaling up by 16. My 1:24 plans are 1:16 at my 2/3 scale. My Hurricane is currently 70% scale at the cockpit, with a 65% scale nose. That is necessary so I can see where I'm going... Seating will be glider-esque supine, with my feet inside the original engine... You'll need to draw an outline and then see how you make things work.
Gentle curves are easy in aluminium, compound curves are wheer it gets interesting. You may well find that flat wrapping in short sections gets you close to true shape. I have an idea for compound wrapping aluminium, but haven't tried it yet.
 

mm4440

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Nobody at the outset promised, least of all me, that these thoughts would lead to a flying article. But I'm intrigued by the possibilities, and maybe others are too. Success and progress always begins with an idea.

An idea may not lead to anything practical; but instant rejection of an idea always leads to failure of one sort or another.

Also note that I paraphrased Paul Dye's opinion that the SubSonex - and probably my idea - is a vanity plane with little practicality to the average pilot/owner. But who knows? Plus I never said this was a marketing idea which would make me zillions.

Instant negativity always causes me to instantly dismiss the negativist.

Instantly.

What's it to you how I or others, spend my time and/or money?

To squash an idea at the outset is really quite destructive to progress. At the very least I, and possibly others, may learn something. Something about design....something about structures...something about jets.

But I suppose there are always people like that. I've certainly run into them often in my life.

I learned to laugh at them and then ignore them.
Not negative at all. It will be an educational project. If you really want to fly a jet you can do like Paul Dye and build a kit or buy a used jet trainer.
 

mm4440

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Saville

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Not negative at all. It will be an educational project. If you really want to fly a jet you can do like Paul Dye and build a kit or buy a used jet trainer.
Do you seriouslyy imagine that I was unaware that if all I wanted to do was fly a jet, I could built a SubSonex or buy a jet trainer?

What I really want to attempt is to see how a design of a scale ME-262 using the PBS TJ-100 works out. That was the point of my original post.

Your response was extremely negative. You were saying:

"Forget your idea and just buy an L-39. It'll be cheaper and faster."
 

Mad MAC

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Cheapest way to get the nose shape in sheet metal maybe to find an external fuel tank off a fast jet / C130 and reshape it out of round.
 

mm4440

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Do you seriouslyy imagine that I was unaware that if all I wanted to do was fly a jet, I could built a SubSonex or buy a jet trainer?

What I really want to attempt is to see how a design of a scale ME-262 using the PBS TJ-100 works out. That was the point of my original post.

Your response was extremely negative. You were saying:

"Forget your idea and just buy an L-39. It'll be cheaper and faster."
 

mm4440

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I suggested an L-29. My first aviation magazine article was "Pony Soldiers" in 1986 on Mustang replicas. I also did an article on homebuilt jets, both with surplus real turbojets and ducted fans and the physics has not changed but the costs have certainly gone up or the dollar has shrunk or both. My particular obsession is a scaled Airacobra. It has morphed into something more useful, a poor person's Stemme. A fighter replica is a challenging project and you will learn a lot. Some projects produce successfully flying aircraft, others waste years and thousands of dollars and a few end up killing their pilots. Not negative, just realistic.
 

Vigilant1

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Is safe single engine flight a requirement for this design? If so, you can save some time by determining the limits that constraint will impose (e.g with the available thrust and the scale wing you are envisioning, along with a rough estimate of the drag (incl drag due to countering asymmetric thrust), you can figure out the max weight you can accommodate.). This may tell you pretty quickly whether the idea is worth pursuing.
My own >opinion< is that I would not find it desirable to have a plane with two experimental engines if it can't fly safely on one.
 

Speedboat100

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Is safe single engine flight a requirement for this design? If so, you can save some time by determining the limits that constraint will impose (e.g with the available thrust and the scale wing you are envisioning, along with a rough estimate of the drag (incl drag due to countering asymmetric thrust), you can figure out the max weight you can accommodate.). This may tell you pretty quickly whether the idea is worth pursuing.
My own >opinion< is that I would not find it desirable to have a plane with two experimental engines if it can't fly safely on one.

Was Me-262 safe to fly on one engine in the first place ?
 

nicknack

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I was wondering if the nakajima kikka which is approximately 75% scale of the ME262 can be another point of reference?
Specs are:
  • Length: 8.125 m (26 ft 8 in)
  • Wingspan: 10 m (32 ft 10 in)
  • Height: 2.95 m (9 ft 8 in)
  • Wing area: 13.2 m2 (142 sq ft)
  • Empty weight: 2,300 kg (5,071 lb)
  • Gross weight: 3,500 kg (7,716 lb)
  • Max takeoff weight: 4,080 kg (8,995 lb)
  • Fuel capacity = 200 us gal
  • Engines 2 × Ishikawajima Ne-20 axial-flow turbojet engines, 4.66 kN (1,047 lbf) thrust each
The newer PBS TJ150 puts out 337lb thrust..
Now if the Price Induction DGEN380 or DGEN390 ever becomes available at a reasonable price, it will be the best choice since it is an efficient turbofan with ~ 550 to 750lb thrust

Personally I think a light weight composite ME163 airframe will probably work very well with 2 PBS TJ100 engines. The ME163 is after all a glider with a Lift/Drag ratio of ~ 25
 
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vhhjr

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You might consider the two place version. That would give you a much larger canopy.

For "Walter Mitty" planning get a set of giant scale RC plans for the ME-262. I wrote an article about the process a few years ago of Experimenter Magazine. Truth in advertising- The closest I ever got to actually doing it was building a non-flying 75% P-39 fuselage.

Vince Homer
 

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mm4440

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You might consider the two place version. That would give you a much larger canopy.

For "Walter Mitty" planning get a set of giant scale RC plans for the ME-262. I wrote an article about the process a few years ago of Experimenter Magazine. Truth in advertising- The closest I ever got to actually doing it was building a non-flying 75% P-39 fuselage.

Vince Homer
Hi Vince, thanks for posting your article. My collection of 215 V-8s (now gone) was started with a 39 replica in mind.
 
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