Profile Help-4 Engined Plane

[CESARNOGUEIRA]

I've just started the fuselage.

http://www.bird.ch/Russians/An22/AN22SU1.jpg

Probably will increase the wingchord.
Finishing all the Motocal calculations.
All foam, carbon/plywood reinforcement.
Glass skin.
3 meters wigspan.
4 Speed 600 geared.
2x8 Sony RC 2400 Matched packs.
100 Mha ESC
Retractable gear.

My doubt:

I would like to have a very scale like flight.
Slow and scale like.
No rolls, no spins, no loops.

Just scale like flight, touchs and goes, low passes, etc...

But I would like also to find the best profile:
Slow scale like flights, but with not too much drag.

What would be the best profile?
Please, help!
Thanks a lot!
Cesar

[davidfee]

Very impressive project!

I presume you mean wing profile (airfoil). I would use an Eppler 205 or a Clark Y and just go with it. Either of those airfoils will give you plenty of lift for slow speed flight. The drag of the E205 will be slightly lower. The fancier, more modern airfoils are better suited to fast, heavily-loaded sailplanes and racers.

Good luck!
-David

[Sparky Paul]

What David said.
Along with your other question about incidence...
Set the wing with the aft part of the bottom along the FRL. The incidence will be built-in.. About 1-1/2 degrees with the Clark or Eppler.

[vintage1]

I remember one very successful scale modeller when asked what profile he used allegedly replying 'Dunno. I took of my shoe and drew round the edge of it'.....

:)

Isn't there some theorem somewhere that says that at the sorts of very low Reynolds numbers we use, its pretty irrelevant...reasonably thick, blunt at the front and rounded on top...:)

[ChrisP]

Originally posted by davidfee
I would use an Eppler 205 or a Clark Y and just go with it. Whaaaaaaat ? American or German aerofoils in a RUSSIAN aircraft ? Antonov would turn in his grave.
Doesn't anyone know any Russian aerofoils ? :D

[steve lewin]

I believe the Epplerov 205 and the Clarkski Y were very popular ;). The Russians, like the Japanese in the early days, did a lot of "borrowing" of designs.

Steve

[CESARNOGUEIRA]

Originally posted by steve lewin
I believe the Epplerov 205 and the Clarkski Y were very popular ;). The Russians, like the Japanese in the early days, did a lot of "borrowing" of designs.

Steve


I'm still laughing a lot with the Epplerov and yhe Clarkski!!!
Very funny!

People, thanks a LOT for the immediate reply!
This is a real friendship place!

One curiosity:
Why the russians decided using a wing aspect ratio tipically found in soarers?
My calculations showed an A/R of 10 !!!
Any clues?

[CESARNOGUEIRA]

Originally posted by Sparky Paul
What David said.
Along with your other question about incidence...
Set the wing with the aft part of the bottom along the FRL. The incidence will be built-in.. About 1-1/2 degrees with the Clark or Eppler.


Sorry, but what is the FRL?
Could you explain a litlle bit more how to set the wing?
My I.Q. is decreasing with age... :D
Thnaks a LOT!;)

[ChrisP]

Originally posted by CESARNOGUEIRA
Why the russians decided using a wing aspect ratio tipically found in soarers?Same reason as on plane like the Liberator, I guess : to reduce induced drag.
I usually drive down to the Speyer Museum 2 or 3 times a year and always go inside the AN 22. It's a beautiful aeroplane. I can well understand you wanting to build it.

[Sparky Paul]

FRL = Fuselage Reference Line.
Usually horizontal.
With a semi-symmetrical profile like the Clark-Y, the nose of the airfoil is above the FRL when the wing's aft section is aligned with the FRL.
This is the incidence for the wing.

[CESARNOGUEIRA]

Thanks a lot!!!:D :D :D