Hi All,

Working an a design for a 1/8 Scale R.A.F. BE2c (Late Version).

[link=http://thevintageaviator.co.nz/projects/be-2/be-2f-reproduction]BE2 reproduction[/link]

The example here is a BE2e, but the Airfoil for the late BE2c is the same (or at least very similar).

This Airfoil looks to be one that will not translate well into this small scale (the construction is possible, but I'm worried about detremental Aerodynamic effects).

Any thoughts?

Cheers,

Hugh

There are definitely more efficient airfoils for models, however that is a low speed design and it will work for a model. If you would prefer to keep the true scale appearance then it should be fine. If you are not that concerned with true scale, then a more modern low speed design would be better. Sopwith camels had a very similar under cambered wing, but the Hanger 9 version has a more modern flat bottom airfoil, and it is a joy to fly. The more scale VK Camel, with an under cambered airfoil, is a bit more tricky, but still fly's well. Most of the new micro park flyers use basically that style and work well.

The problem is not the airfoil shape -it is the strength of the scaled down shape
H9 does a flat bottemed setup because it's easy to do and is thicker than the original full scale shape.
Th thicker shape is more rigid
The tiny EFlight curved foam setups are curved to again provide strength at lowest possible weight - that and thread rigging. (I have had em and they work well but you have to get em rigged correctly).
Airfoils are ALL simply compromises for the speed and load on the airframe
No exceptions.

For a light slow flying model the thin shape of the old WW1 airfoils is actually not too bad an option at all. A buddy of mine built a 36 inch SPAD XIII that used the scale airfoil and it performs well with a decently gentle stall.

If you opt for a fully functional scale rigging with the landing and flying wires being functional then the scale airfoil or a flat bottomed with scale upper will do fine. The key here is that by using functional rigging the small section height of the spars will be OK because the rigging ties the two spars together. In the end the upper and lower wings then form a strong structure much like the truss form of a crane boom or climbing crane tower.

Yes the rigging on the VK camel is functional and required.

Thank you all for your input.

I know it sounds ambitious but I do intend that the rigging will be functional.

I want the model to be as scale as possible, but it would be real nice if it can fly well (and is easy to fly).

I have a date with Gary Sunderland next weekend (I am interviewing him for an article I am writing for our club news letter).
I have noticed that most if not all of his later builds (99% of which are his own designes) use sale airfoils.
He has experience in full sized glider building going way back, and uses the same techniques in his construction methods. He told me on th phone the other day that he had tried a 1/8 scale BE2c years ago for free flight with scale airfoil. He said he had to rebuild it later because the trailing edge warped, but said that if I was to use a strip of thin ply (say 5mm Wide) for the trailing edge, I would probably avoid this happening.

Cheers,

Hugh

Given the scale you've chosen to work to making the rigging fully functional should not be much problem at all. The fittings for adjusting the rigging may be a bit of an issue but with a bit of imagination I'm sure you can come up with something or just purchase some Proctor turnbuckles.

proctor turnbuckles are nice and come in several sizes. A bit pricier, but well worth it.

Yes, I think so too.

Cheers,

Hugh

It has been a few years since last speaking to him, but Brian Taylor of the UK told me he tried scale airfoils on his WW2 model designs, more for the fact that he got critisized so often in the early days. No scale need for them but he used them anyway. The RAF 20 and 30 seriesdid not come into general useage until the middle 1930's when the future WW2 designs were new.

Prior to that era, they used the 1 to 19 series I would assume for RAF designs. In the jet era they went to a whole 'nother series of numbers.

Wm.