How to determine the optimal cruise and loiter conditions of an aircraft/aircraft concept?

Question

I am extreamly interested in aeronautics and aerospace. I want to learn how to engineer the planes and i have found a program that does all but determine the optimal cruise and loiter conditions. Can anyone tell me this?

Answer 1

aircraft stability can mean longitudinal (i.e. pitching controlled by the elevator), lateral (i.e.rolling controlled by ailerons) or directional (i.e.yawing controlled by the rudder)

by cruise, i assume you are referring to steady flight i.e. longitudinal static stability. for that, you need -ve moment coeff-angle of attack slope, and +ve moment coeff at zero angle of attack (read up-the explanation is quite interesting...this is the reason why we have horizontal stabilizers)

anyway, the trim velocity= sqrt(2W/(rho*A*C_L)) (balancing vertically). the pilot can maintain longi. stability for different velocities by controlling the elevator.

anyhow, this is very vague...if you need to know anything more specific/technical with equations and proofs, email me and I'll try to reply