Require help, aerodynamics

stevebelfast · June 18, 2009, 07:04

Been having problems with some questions can anyone help...?

.. Describe three ways that can be used to increase the lateral stability of an aircraft.
.. Discuss the effect of the tailplane and wing on longitudinal static stability on an aircraft in flight. Assume the rudder remains in the ‘stick fixed’ position.
.. How the flow velocity over an aerofoil may exceed Mach 1 during subsonic flight.

I would be so greatful of any help?!

bunty_abhi · June 19, 2009, 14:40

All 3 ques u asked can't b answered here properly, but i can give u references where u can get ur answers directly.for ur 1st & 2nd ques on Stability u can refer these two books.
STABILITY & CONTROL by PERKINS or AERODYNAMICS by L.J.CLANCY.

For ur 3rd ques:This can be explained by taking an eg. of a Symmetrical aerofoil section at low incidence, the local airspeed adjacent to the surface just outside the boundary layer is higher or lower than the free stream speed depending on whether the local static pressure is less or greater than the ambient. So that the velocity somewhere on the aerofoil exceeds that of the free stream. Thus as the free stream flow speeds up the mach no at a point somewhere adjacent to the surface reaches sonic flow conditions before the free stream. and this free stream mach no. (corresponding to M=1) is called as Critical mach no. Beyond this mach no. flow is mixed, partly supersonic partly subsonic, over the surface of the aerofoil .

June 18, 2009, 07:04	Require help, aerodynamics	#1
stevebelfast New Member Steve Join Date: Jun 2009 Posts: 1 Rep Power: 0	Been having problems with some questions can anyone help...? .. Describe three ways that can be used to increase the lateral stability of an aircraft. .. Discuss the effect of the tailplane and wing on longitudinal static stability on an aircraft in flight. Assume the rudder remains in the ‘stick fixed’ position. .. How the flow velocity over an aerofoil may exceed Mach 1 during subsonic flight. I would be so greatful of any help?!

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June 19, 2009, 14:40		#2
bunty_abhi New Member Abhishek Pateria Join Date: Jun 2009 Posts: 2 Rep Power: 0	All 3 ques u asked can't b answered here properly, but i can give u references where u can get ur answers directly.for ur 1st & 2nd ques on Stability u can refer these two books. STABILITY & CONTROL by PERKINS or AERODYNAMICS by L.J.CLANCY. For ur 3rd ques:This can be explained by taking an eg. of a Symmetrical aerofoil section at low incidence, the local airspeed adjacent to the surface just outside the boundary layer is higher or lower than the free stream speed depending on whether the local static pressure is less or greater than the ambient. So that the velocity somewhere on the aerofoil exceeds that of the free stream. Thus as the free stream flow speeds up the mach no at a point somewhere adjacent to the surface reaches sonic flow conditions before the free stream. and this free stream mach no. (corresponding to M=1) is called as Critical mach no. Beyond this mach no. flow is mixed, partly supersonic partly subsonic, over the surface of the aerofoil .