Linked Questions

3
votes
3answers
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 ...
2
votes
3answers
239 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 ...
0
votes
3answers
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 ...
5
votes
2answers
5k views

What are the properties of the wing (airfoil symmetry, angle of incidence) of an aerobatic aircraft?

On an aerobatic aircraft, such as an Sbach342, what type of airfoil does it have and what angle of incidence does it have in relation to the fuselage?
4
votes
2answers
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 ...
3
votes
2answers
8k views

How are empennage airfoils chosen?

Empennage airfoils are usually symmetric. What is the process behind choosing the airfoil used in the tail of the airplane? Is it related to the stability? And then how would the angle of attack of ...
1
vote
2answers
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 ...
1
vote
2answers
187 views

Need to add elevator downforce to total lift when sizing wing area?

Do I need to add elevator downforce to total lift when sizing wing area? Say a small airplane weighs 1,000 lbs, and both the wing and elevator have a max Cl of 1.5, and my elevator is 20% of my wing ...
8
votes
1answer
1k views

Are the vortex generators on the Cessna Caravan necessary and sufficient for safety of flight?

I've been doing some reading about the C208B (Cessna Caravan) in prep for my new job flying cargo; I came across this article which (as far as I can tell) is a transcription of litigation surrounding ...
8
votes
1answer
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?
4
votes
1answer
290 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 ...
3
votes
1answer
119 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 ...
1
vote
1answer
1k views

How to calculate the location of C.G. A.C. & N.P. in static longitudinal stability?

We are in the conceptual stage of design and, using Raymer & Nicolai as references, I am doing a rough calculation of "power off" neutral point (N.P.) to find the optimum c.g. and a.c. positions. ...
1
vote
1answer
289 views

Why is subsonic lift at 25% of chord? [duplicate]

I pretty much understand the way a wing works and the different ways of explaining it, what I don´t understand is why the lift on a subsonic wing manifest itself at the 25% chord.... The 50% chord ...
0
votes
1answer
1k views

Which moments are acting on a flying airplane?

I would like to ask some clarifying questions regarding the moments acting on a flying airplane. My understanding is that there are following force: Weight (pointing down and applied to the CG of ...

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