If a hypothetical aircraft, which is a tailless straight flying-wing with no fuselage, has:

• no sweep,
• an AR = 9,
• a dihedral angle of 3 degrees,
• a slight tapering of 3 degrees on each edge,
• thickness 10% at the tips, 15% at the root and 20% at the centerline,
• a low wing loading, i.e. 50 kg/m2,
• and the CG within limits and slightly forward than the neutral point (at 25%?),

what kind of airfoil characteristics - or even better - what specific airfoil examples (or at least, a specific airfoil category) would provide both low induced drag and ample lift ability at low speeds of 50KT, but still have low resistance at higher speeds i.e. at 200 KT?

Specifically, how much camber and reflex (approximately) should be sought for each of the different segments of the wing (centreline/root/outboard/wingtip - having in mind the required stability in yaw through a slight washout and symmetrical/negative reflex at the tips) and what should be the Centre of Pressure positions (in chord percentage), at slow flight or in high-speed cruise?

I know it may be a fairly wide question with a myriad of possible answers but I would be grateful to see some examples, so I can have some notion on what the spectrum for these airfoil characteristics should be and to better understand via examples how the airfoil parameters, the centres of pressure and the centers of gravity will affect longitudinal stability.

Thanks

If a hypothetical aircraft, which is a tailless straight flying-wing with no fuselage, has the following characteristics:

• moderate forward sweep
• an aspect ratio = 9
• a dihedral angle of 3 degrees
• a slight tapering of 5 degrees on each edge
• wing twist (10 degrees of total incidence difference between centreline and wing tip)
• positively cambered airfoil at centreline, slightly less at the root, minimally positive camber at the inboard section, symmetrical outboard section, negative camber from there towards the wing tips
• thickness 10% at the tips, 15% at the root and 20% at the centerline
• a low wing loading, i.e. 50 kg/m2
• slightly forward CG

And if the required stability in yaw (proverse yaw) is considered to be ensured through sufficient wing twist and symmetrical airfoil/negative camber at the tips,

what kind of airfoil characteristics - or even better - what specific airfoil examples (or at least, a specific airfoil category) would provide both low induced drag and ample lift ability at low speeds of 50KT, but still have low resistance at higher speeds i.e. at 200 KT?

Specifically, how much camber and reflex camber change (in ratio to symmetrical) should be sought for each of the different segments of the wing centreline, root, outboard section and wingtip?

Or, would it be sufficient if the whole planform has an identitical airfoil shape (scaled for chord length due to taper)?

What would be the Centre of Pressure positions (in chord percentage) of such a wing at slow flight or in high-speed cruise?

——

I know it may be a fairly wide question with a myriad of possible answers but I would be grateful to see some examples, so I can have some notion on what the camber/reflex camber for these wing characteristics should be, and to better understand via examples.

Thanks

If a hypothetical aircraft, which is a tailless straight flying-wing with no fuselage, has:

• no sweep,
• a dihedral of 3 degrees
• a slight tapering of 3 degrees on each edge,
• thickness 10% at the tips, 15% at the root and 20% at the centerline,
• a low wing loading, i.e. 50 kg/m2,
• and the CG within limits and slightly forward than the neutral point (at 25%?),

what kind of airfoil characteristics - or even better - what specific airfoil examples (or at least, a specific airfoil category) would provide both low induced drag and ample lift ability at low speeds of 50KT, but still have low resistance at higher speeds i.e. at 200 KT?

Specifically, how much camber and reflex (approximately) should be sought for each of the different segments of the wing (centreline/root/outboard/wingtip - having in mind the required stability in yaw through a slight washout and symmetrical/negative reflex at the tips) and what should be the Centre of Pressure positions (in chord percentage), at slow flight or in high-speed cruise?

I know it may be a fairly wide question with a myriad of possible answers but I would be grateful to see some examples, so I can have some notion on what the spectrum for these airfoil characteristics should be and to better understand via examples how the airfoil parameters, the centres of pressure and the centers of gravity will affect longitudinal stability.

Thanks

If a hypothetical aircraft, which is a tailless straight flying-wing with no fuselage, has:

• no sweep,
• an AR = 9,
• a dihedral angle of 3 degrees,
• a slight tapering of 3 degrees on each edge,
• thickness 10% at the tips, 15% at the root and 20% at the centerline,
• a low wing loading, i.e. 50 kg/m2,
• and the CG within limits and slightly forward than the neutral point (at 25%?),

what kind of airfoil characteristics - or even better - what specific airfoil examples (or at least, a specific airfoil category) would provide both low induced drag and ample lift ability at low speeds of 50KT, but still have low resistance at higher speeds i.e. at 200 KT?

Specifically, how much camber and reflex (approximately) should be sought for each of the different segments of the wing (centreline/root/outboard/wingtip - having in mind the required stability in yaw through a slight washout and symmetrical/negative reflex at the tips) and what should be the Centre of Pressure positions (in chord percentage), at slow flight or in high-speed cruise?

I know it may be a fairly wide question with a myriad of possible answers but I would be grateful to see some examples, so I can have some notion on what the spectrum for these airfoil characteristics should be and to better understand via examples how the airfoil parameters, the centres of pressure and the centers of gravity will affect longitudinal stability.

Thanks