120 views

How does the stick force and behaviour of aircraft relate to the CG locations?

I'm struggling with developing an intuition for flight behaviour and stick force with CG locations. Assuming conventional wing and tail configuration, When the CG is moved from aft to forward, the ...
126 views

Can I assume that aoa on horizontal stabilizers correspond to aoa of the main wing?

I am in the process of designing a small wing (Re ~ 50-100k) and am wondering if given (a) the Cm on the main wing is relatively small at low aoas, (b) the horizontal stabilizer will produce lift as ...
129 views

Wing moment - providing stability or not [closed]

It is said that wing alone is unstable, because it provides a nose up moment, so tailplane is needed to damp it. But normally wing provides a pitch down moment (as far as I know, apart from very high ...
12k views

Should the pitching moment be up or down?

I had a question regarding the direction of the pitching moment. To make sure we are on the same page, here is what I know so far (please correct me if I am wrong). Lift acts through center of ...
4k views

Why do airfoil's trailing edges point downward?

The trailing edge of and airfoil is mostly pointing downward. Is there any reason for that? Down wash increases drag and down wash is due to the direction of air pointing down. If the trailing edge is ...
9k views

How does the line of thrust affect longitudinal stability?

I’ve been studying Pilots Handbook of Aeronautical Knowledge FAA-H-8083-25B and on p 5-17 they talk about thrust line and stability. Can someone explain why the moment changes when thrust is applied? ...
241 views

How does washout increase static pitch stability in subsonic swept wings?

How does washout increase static pitch stability in subsonic swept wings, more specifically in slow moving aircraft (eg. ultralights), 15mph to 60mph? I understand washout is used to delay full ...
2k views

Can the design for neutral stability reduce trim drag?

If one were to design an aircraft to have neutral longitudinal stability would this reduce the required horizontal stabiliser surface and hence trim drag?
3k views

Can lift be created without air downwash?

I was looking at the great site code7700.com, but I don't really understand their explanation of lift and drag: The so-called infinite wing displaces air for a while, but the air particles ...
6k views

What is the relation of stall speed to the position of the center of pressure with respect to the centre of gravity?

Would the centre of pressure being aft or forward of the centre of gravity (CG), reduce or increase the stall speed in straight and level flight? I know it is a weird question, I just cannot figure ...
259 views

Can the back tail of an airplane move the neutral point backwards?

I'm currently in the process of designing a prototype aircraft and since I don't have very much experience with this I have the following question: I know that the center of gravity of an airplane ...
15k views

Why are there no cargo aircraft with "flying wing" design?

From that I have seen so far, the "flying wing" design (like the one of B-2 Spirit and Northrop YB-49) has superior performance but also a few notable problems that make it difficult to use for ...
291 views

Does a tandem ultralight need flaps on the rear wing if the front wing has flaps?

Does a tandem ultralight need flaps on the rear wing if the front wing has flaps? I understand that most Rutan canards don't have flaps as I was told if the main wing has flaps, the canards need one ...