What happens without a tail?

If you have a wooden model of a plane, I would not advise to rip off the tail. If you throw the model without tail, it will dive to the ground. Why? Every airfoil has three forces. Lift, weight (both vertical) and drag (horizontal). If lift and weight are placed on the same spot, the airfoil is stable. But most airfoils are not stable. The lift force is mostly located after the weight force. So it generates a turning moment. This turning moment is compensated with the down pushing force of the horizontal tail surfaces.

swepted wings

Unswepted wings

Tail on tips

Low CG

A canard has an upward force in the horizontal "tail"-surfaces.

Flying wings, why?

Every plane (with a tail) also has a long fuselage to fix the tail to. This fuselage and tail create extra drag. Performance gets less due to this drag. Many designers came to the thought: "why not delete the fuselage and the tail". Flying wings were born.

The name flying wing is not totally correct. Most full-scale designs still have some sort of fuselage. The Horten-brothers and Northrop made (to my idea) the only pure flying wings. The Horten IX V2 (1945) and the B-2 (1990’s) have proven that the concept can be achieved. Other designs have fuselages and fall under the name "tailless airplanes". But some still have vertical tail surfaces. So… we make it ourselves simple and call them all "flying wings".

How flying without tail?

There are four ways when using a rigid wing (not a pure textile wing like a parasail).

  1. Give the wing an arrow form (sweep) and twist the wing. If you sweep the wing backwards you need to twist the wing softly downwards.
  2. Use an auto stable airfoil (lift- and weight forces on the same point). Here you don’t have to use sweep. That is why they are called unswept designs. Sometimes designers do use forward sweep. I will explain this later.
  3. Place horizontal surfaces on the tips of the wing. This is not a pure "tailless design". Although it looks a bit like it.
  4. Place the center of gravity very low.

Swepted flying wings

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.



  1. 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.


  1. 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. Site.
  2. Due to the sweep is construction more difficult than the flying wings with auto stable airfoils, which mostly have no sweep.

gal.jpg (23295 bytes)
General Aircraft GAL 56 (third version)
A lesser-known English flying wing that had a 36,4 degree sweep.


The Utopia, a modern competition hang glider.
Made by BrightStar Gliders and flown here by Brian Porter,
a many times champion in the hang gliding competition.
You can clearly see the sweep and the control surfaces.
I got the picture from Brian Porter.
Click the picture to get an even larger size (JPG, 636 kB).


Designs using auto stable airfoils

(also called unswepted flying wings)

These designs use an airfoil, which doesn’t require a sweep. Therefore they are the most compact version of a flying wing. Fauvel, a French designer, became famous with his unswepted designs. These designs are without vertical tail very unstable, so most designs have a vertical tail.

This airfoil (CJ-5) is an example of an auto stable or reflexed airfoil. Note that the trailing edge goes up. You can see a reflexed airfoil as a normal airfoil with a tail-airfoil in one.


pelican_3d.jpg (32158 bytes)
The Debreyer Pelican, a compact ultra light, uses the 17% thick Fauvel reflexed airfoil.
"Ideal for a beginner" as the manufacturer says.
Click picture to go to a page about this remarkable airplane.


Click for link to Marske site (www.continuo.com/marske)
Marske Pioneer, available as kit and on plans (picture given by Buddy and Lloyd Watson)
Click picture for link to site of Marske (www.continuo.com/marske) and also see the Marske Monarch.



  1. Less work on basic design. You don't need to calculate twist and sweep.
  2. Compact. Since (mostly) no sweep is used, these designs are easy to place in a hangar.
  3. No sweep means no difficult main spar connection.
  4. Auto stable means no stall and no spin. The condition is that the CG (centre of gravity) is placed on the right spot.


  1. Reflexed airfoils have less lift than normal airfoils. So more wing area is needed to have the same lift.

Tails on tips

This concept is, according to some people, not a true flying wing. Euh... I don't see a classic tail, or a canard, so I see it as a flying wing.

What has happened in this concept? The wing has a great angle of sweep (a German design had 40°). The classic horizontal tail surfaces are placed on the tips of the wing. This way you have the necessary down force to compensate the turning moment of the wing (the force-arm (distance between center of gravity and elevators) is long enough) and you don't need to have a long fuselage to hold the tail. Most known designs have the vertical tail also placed on the tip. Here you can also combine the elevators with the roll-rudders (combination known as elevons).

The German company Blohm & Voss did some tail-on-tip-designs in WW II. The Luft '46-site (see links nurflugel-site) has many of the unfinished projects of the Luftwaffe. They have superb 3D-drawings of some of these designs.


A nice picture of the Blohm & Voss P212-3 made by Tor Pedersen (permission granted by Dan Johnson) Click picture for link to Luft '46 site (www.luft46.com) to see more of the last German designs of WW II.


I got these pictures from Bjorn Rabben. They show his model of the Blohm & Voss P212. He did use elevons in the main wing instead of the original rudder configuration.

Click the thumbnails to see the larger pictures.

I received this mail from Antonio Fernández (MEWGULL@terra.es), he seems to have had some problems, but now has a good model: "Have been experimenting with "backyard Nurflugels", small flying wings. I first built a high dihedral, 212-01 model that has the fins over the wing, at two-thirds span. It was horrible! spin both sides, flat spins, the lot! The CG range was almost nil (interestingly you must add the weight in the extreme tail, the exhaust of jet!) and then I made a larger 212-03 that has the double winglet-fin assembly on the tips...Steady as a rock, like an arrow on its trail. The winglets act like this: if raised inner only, like ailerons coupled to rudder, gentle turns. If depressed outer, like normal aileron, but sharp response. The rudder makes pronounced almost flat turns, that if exceeded tend to crab and in the extreme, swings out. But stable flyer when all straight and no spins, good cg range and very responsive, proportional to inputs of command. Used reflex profile and no elevons in wing. I´m building larger one with electric fan unit... "


Q: I don't know them yet. Any reaction is welcome. A: (From Kenneth M. Dorsett (Specialist, LMTAS Aerodynamic Stability & Control)) "I have some experience with such surfaces on high performance tactical aircraft; however, my comments should apply to a low-speed glider as well. Advantage: A large moment arm with respect to the CG makes these surfaces ideal lateral-directional controls. A great deal of control power can be generated by a relatively small surface. By staggering the surface aft (like Blohm & Voss did), you can generate a good deal of longitudinal control as well. These surfaces typically remain effective to very high angles of attack (AoA)."



Q: I don't know them yet. Any reaction is welcome. A: (From Kenneth M. Dorsett (Specialist, LMTAS Aerodynamic Stability & Control)) "The primary disadvantage comes from structural integration problems. Tip mounted surfaces such as these are hard to keep stiff -- particularly on a thin-winged, high speed aircraft."


Low CG

The moment created by the wing gets (fully or partially) compensated by the very low CG. This technique is often used with ultra light. Mostly hang gliders (using weight shift as flight control) use this technique to its full use. "Mitchell used this technique for his B-10 flying wing ultra light." This quote from an Air Enthusiast edition probably mentioned that if the cockpit would be higher placed, that the control surfaces needed to be larger to control the airplane. The newer U-2 of Mitchell has a higher placed cockpit, but it also has a longer force arm between the CG and the control areas (the B-10 has a straight wing, while the U-2 has some back sweep). Both airplanes use the low CG technique partially. Flight control is done by control areas hung under the trailing edge of the wing.


  1. Very easy in design. No fuss with twists and sweep.
  2. You still can use airfoil with some pitching moment Cm like a "normal" airplane (not a flying wing). This way lift is larger than the auto stable airfoils used in unswepted designs.


  1. You have not the opportunity to place pilot or engine or equipment in the wing. You cannot make profit from the available space in the wing.
  2. A cockpit hanging under the wing makes more drag then an integrated cockpit in the wing. Probably the reason why Mitchell made his second design, the U-2, has an integrated cockpit.

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