Swept flying wings

a tale of no tail

What is achieved by using sweep and twist? Well, the tips provide the compensating down- (in case of backward sweep) force or up- (in case of forward sweep) force to the turning moment of the airfoil in the center.

The angle of sweep can be shown in two ways. One is to the leading edge (used by Horten), the other is to a line, which is placed on 1/4 of the wing. Make sure, when using data of exciting models, that you don't use the wrong angle. If not mentioned which angle they use, take the one to the 1/4-line.

The twist-angle is the angle between the airfoil at the root of the wing (nearest to the fuselage) and the airfoil at the tip of the wing.

Advantages:

  • When using a twisted wing, the airfoils have not the same angle according to the longitude axis. This leads to good situations if you use a backward sweep. If the center section of the wing stalls, the tip airfoils are not near the angle to stall. If you place elevons on these tips, you can still control the aircraft. You can avoid getting the plane into a spin.

Disadvantages:

  • If you are planning to make a model, be prepared to see some complicated formulas in your research. But don't let it scare you. A friend of me made some good models, just be guessing the angles or using data from full-size airplanes. I have seen a site that gives a good help in choosing the right angle of sweep and twist. Just read a bit of the given theory and use the curves to determine the angles.  http://www.mh-aerotools.de/airfoils/flywing1.htm
  • Due to the sweep is construction more difficult than the flying wings with auto stable airfoils, which mostly have no sweep.

FLYING WING DESIGNER

Recently Marko Stamenovic made a very useful excell that help you a loooot when designing your own RC flying wing with swept wing. You can find all the info here.

General Aircraft GAL 56 (third version)

These two gliders of the German brothers Horten also use sweep and washout.

The lower one, the Horten Ho XIII, even has a very extreme sweep. The left one has a pilot lying on his belly. For more info about that, go see my proned pilots page. Permission to use pictures from Sharkit (www.sharkit.com). Sharkit is a firm which makes resin models of unconventional and experimental flying machines.


If you like to test a RC model of a flying wing with extreme sweep, go try the Horten H13B jet (electric ducted fan) of RBC (www.rbckits.com). Here you can see the model made by Erik Van Schaik.

Another drawing of Graham Ward.

Both engines would make this airplane uncatchable by enemy-fighters. But ... it never left the drawingboard. more detailed info at www.luft46.com

 

 

The lower video shows me inside the two-seater trainer of the SWIFT based in Beauvechain in Belgium. Contact Avia Airsports for flights in it.