Merry Christmas folks!

I has a soviet made U/C airplane building set, the wing span are at 40 cm/16". The fuselage are made of whole spruce and the wings of spruce plywood. There are not building manual or plan. The set are made in Gomel in belarus.

How size engine are best for the airplane at 40 cm/16" wingspan?

Jens Eirik

Hi Jens,

What is the intended purpose of this model? What is the weight?

Jim

I has not builded the airplane therefore i can not know how much will the weight be, nothing techical data in the set.. The airplane are for newbeginner.

Jens Eirik

I bet one of the ubiquitous MARZ MP3 2.5 cc diesels was the intended motivator.

2.5 cc diesel are too big for the airplane with 40 cm/16" wingspan. Must be smaller engine, how small are the engine?

See at the pic of the set of airplane..

Jens Eirik

I bet a half A engine .049 in. ^2 or < 1 cc. would power that well. Or a .020 or so for slower beginner flight.

Thanks, i can take the 0.49 engine first and see how it flies well. I shall take copy of the airplane and make in new material of same sort wood. The parts in box shall be in peace.

Jens Eirik

Is that prop in the center pic part of the kit? If so, perhaps its size will give a better guess.

George

That airplane, made out of hardwood, is going to be (1) heavy and (2) tail heavy. It is going to have to have some nose weight to be flyable, and fly fairly fast to stay in the air. Looking at it I agree that the MP3 2.5 cc is a little much. Maybe one of the heavier 1.5 cc diesels. The prop and the width of the cutout for the engine should be good clues. For an 049, I would use balsa and perhaps extend the nose a little.

Propeller are marked in size x pitch in mm: 200x200 (7,87"x7,87").. The pitch are large as diameter, maybe a stronger engine to run a propeller with big pitch..[X(]

Jens Eirik

Jens,

I tried to respond, but timed out (?)

Go with Jim Thomerson's ideas.

I don't know cyrillic characters, but the large wording on the box looks like it would sound like something meaning Model Monoplane. I can't read the small print. If you read Russian, or know someone who can, more information might be right there.

\BEST\LOU

I am speaking and reading russian since i am married with ukrainan wife.

Кордова� модель �амолет mean Line controlled model air plane, the small text are informaion where the airplane was produced in Гомель�кий Завод Спортивного �амолета (Gomelskiy sportairplane factory).

There are not technical information, nothing text about engine size..

The airplane are smaller than other airplane with 2.5 cc engine and the width of the cutout for the engine are 21 mm/0,826 inc.

Jens Eirik

Wow! 8*8 prop. It would take a manly .049 to swing that, even a 1.5 would have trouble. How about flying it with a 2.5cc on *very* long lines

Jens
if the motor hole is 21 mm wide it fits EXACTLY a MK16 and MK 17 1.5cc diesel, of course russian. The model has the right wingspan for it. The 200X200 propeller should NOT be good for this engine, but it could in some way work.
Merry Christmas, Ugo.

Thanks! But why 200x200 propeller in the kit can i never get answer []

Merry Christmas to all folks!!!

Jens Eirik

...And Merrry Christmas to you as well.

I had a slight exposure to Czech, and to the Greek alphabet, so my guess at the wording on the box was in error because I was only in the neighborhood, not fully competent. I can live with that.

I wish you had more to work with than the box words. You have some good comments on the Russian Mk engines. Maybe the smaller of those, suggested as fitting the engine bearer width, would suit this model - if it is built with balsa as major wing and fuselage wood, and other wood as appropriate.

Best of luck! I, at least, am interested to hear of your successes with this challenge...

(I also wish I had another of the D-A 2.5 diesels that worked so well for me in the 1950's... but reality is, wishes aren't.)

\BEST\LOU

Considering the prop size and the shape of the airplane I would guess that it is a trainer for some "go fast" event like team racing and Jim's original suggestion of the MARZ 2.5cc is probably correct.

I hope everyone had a Joyous Christmas.

George