# Could this helicopter's body be a flying wing?

This question: Could a helicopter fly like a plane this way? asks if a helicopter can turn sideways using additional wings to tip forward to allow the rotor blades to act as a propeller. The tail-setter and other types of planes came up as answers. Similar to the tile Setter their first function of this aircraft would it be to hover then to fly as a plane.

Would this model helicopter with a body shaped of a flying wing be able to fly at a 90 degree angle and at a 90 degree twist transferring lift from the rotor blades to the body?

I have sketched out a picture below on how on might and apologize for imperfections. The body could be longer to create more wing span.

The pilot would need a special seat or controls to adjust for tilt but they would enter it like a normal helicopter. Could this model fly, keep maneuverability and feel of a helicopter foremost?

The pilot would only need to dive Rotor head first to allow the body to serve as a wing.

• Have you seen the Boeing V-22 Osprey? – Jan Jun 4 '19 at 7:31
• Can you include the annotation for the numbers in the images? It is not really clear what the various lines are supposed to represent. – Jan Hudec Jun 5 '19 at 19:02
• @JanHudec number of wings – Muze Jun 5 '19 at 19:31
• You talk of a model, which is by definition unmanned, and of a pilot. Which are you really asking about? – Guy Inchbald Mar 13 '20 at 19:57

No, you need sufficient wing span to produce lift without excessive induced drag.

Lifting bodies are only a thing of hypersonic flight where the induced (component of wave) drag is tiny compared to the form (component of wave) drag.

Induced drag is an unavoidable side-effect of producing lift over a finite span. It decreases with wing span, and with dynamic pressure (which in turn grows with density and square of speed; indicated speed is a square root of dynamic pressure). So at slow speed, you need considerable wing span to generate lift efficiently. This applies also to helicopter rotors, which is why they have such large diameters.

Since the other component of drag, form drag, increases with dynamic pressure and cross-section, the optimal wing span decreases with speed. But even jets still have quite high aspect ratio (square of wing span to wing area). Flying bodies without much any wings only become efficient well into supersonic area—and keep in mind that anything resembling a propeller (including tiltrotor) is limited to subsonic.

(At supersonic speeds, the mechanism of drag creation is different, called wave drag, but it still has a form component and induced component and the induced component still depends on wing span and dynamic pressure in the same way.)

• What would you do to improve on this design? – Muze Jul 7 '19 at 16:29
• @Muze, it's not possible to work with a design without specified goal—and most mission profiles have pretty good designs covering them already. – Jan Hudec Jul 11 '19 at 20:47
• The goal is to fly like a wing at higher speeds that far exceed any helicopter today. – Muze Jul 11 '19 at 20:49
• @Muze, I could imagine something like an airplane with a foldable rotor. Basically similar principle as F-35, but a foldable rotor instead of the fan to reduce the induced power in hover and therefore increase payload fraction. The reason for folding the rotor is that you can't use it for propulsion at higher speeds, because the tips would go supersonic, and without being stiffened by the centrifugal force the blades are quite fragile, so you'd have to at least align them with the flow to reduce the aerodynamic forces on them. Still subsonic; above the usual M0.85 nothing is efficient. – Jan Hudec Jul 11 '19 at 21:00