"Airfoiled" fuselage

[Luis Strufaldi]

Hello Everybody,
This is my first post, so please, be nice to me.

I remember having read somewhere (a long time ago) about "Airfoiled" fuselages, that is , constructing the inside .... er  side, of the fuselage straight and letting the formers give the outside kind of an airfoil shape. That would, supposedly, help in overhead line tension.

I'm interested to know what you think about it and, if there are any experts around, how it would affect the overall performance of the airplane.


Luis Strufaldi
Brazil

[frank carlisle]

It's not a good idea. It would look terrible. I don't think it would make much difference in how the plane flies but it would sure be ugly from a top view.

[phil c]

the fuselage already acts as an airfoil(although a pretty poor one) as several people have pointed out.  If you lay out a diagram of the top view, when the fuse is tangent to the circle, the plane is traveling around in a sideslip and the air is hitting the fuse at roughly 1-2 deg angle of attack.  The air hits the left side of the nose and probably generates a bit of lift.

Probably much more important is getting the fin and rudder trimmed so the plane flies as straight as possible in all the maneuvers.  If the plane is falling in at you in overhead maneuvers you probably have a fin/rudder alignment problem.

[Dennis Adamisin]

Luis
I see this was your first post so WELCOME to the Stunt Hanger. 

Over the years many folks have alked about and tried what you are doing, but ultimately it is not nearly as effective as it seems it should be.  One real problem is that even if you COULD generate sufficient lift from the fuselage, the airfoil shape also produces a pitch IN, that is turning the nowe toward the pilot.  The way to counter that is to kick the rudder outboard... and it ends up behaving pretty much like a "straight" fuselage with rudder offset.

If you do try it mayke sure you report back on how it works out for you..!

[RC Storick]

I have read the replies here and on SSW. Despite what anyone says it works fine. My S6B Super Marine has a extremely air-foiled fuse shape. I will take a picture ASAP to show the example. It has good line tension in all areas.

In control line building you need not worry about Real Life Applications of aerodynamics. Real airplanes done fly on wires and we don't fly in scale air. Air-foiled fuselage's look more realistic and more shapely. The truth of the mater anything will work in the Hobby as long as its straight-light-rigid with ample power.     

[Dave Cook]

Luis
Airfoil Fuselage
I first was exposed to lifting fuselages in the late 40’s. It was being used by a guy named Sammy Frye in Weymouth Mass. He was also the first guy I saw fly inverted.

I have used airfoil fuselages on Barnstormers, Noblers, T Birds and some of my own designs with good results. They were all good flying airplanes, but how much the lifting fuse contributed is anybodies guess.

I would say that it won't hurt anything. The trick is to keep the airfoil shape very subtle with only a 1/8 to 3/16 shim to the outboard fuse side so the airplane looks stock. The high point of the side airfoil should be about the same as the wing airfoil.
It won't add anything to a round, gun barrel fuselage. If you don't have a flat sided fuse, like a Nobler as opposed to an Aries, there is just not enough area to contribute lift. This falls in about the same class as discussion over fuselage side area. The Nobler has a lot of side area aft of the CG while there are a lot of jet style ships around with a lot of area ahead of the CG. The act different overhead but both can be trimmed to fly well.
I saw pictures of a Chinese airplane years ago with a large outward lifting airfoil tip plate attached to the outboard wing. The same principal - ugly but effective.

Can I prove that that lifting fuse is an advantage? – no but it can make the pilot feel better.
Dave Cook