Landing gear design
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The document discusses several key factors in landing gear design: 1. Landing gear must provide adequate ground clearance for the propeller tips and allow the plane to rotate on takeoff and landing to achieve the stalling angle of the airfoil. 2. Factors that affect landing and takeoff speeds and angles include the airfoil characteristics, planform, effect of flaps, and ground effect. 3. NASA's droop wing design increases takeoff and landing angles by delaying wing tip stalling and providing effective aileron control in a stall.
Landing gear design
- 1. LANDING GEAR DESIGN -to provide adequate clearance b/w prop.Tips n ground -to permit the plane to rotate on both taking off n landing so that wings AoA come close to the stalling angle of airfoil -the airfoil characteristics n Rn at landing n takeoff speed -adjustment of section values to those for wing’s AR n plan form -the effect on the stalling angle of flaps when extended. -the impact of ground effect - Nasa droop increases landing/takeoff angles
- 2. Landing gear Fore –plane characteristics To estimate the landing/takeoff speed n angle -Section value adjustments -High lift devices –takeoffs r optional ;landings r unavoidable -Ground effect- -reduction in stall AoA n in induced drag
- 3. NASA safe wing droop delays tip stalling n provides effective aileron in stall -Occupies 38% of semi span -Provides 4 degree more in takeoff/landing - longer landing gear increases tail angle that brings AoA attack above the stall for takeoffs/landings - reduce the tail angle to avoid the stall -Longer landing gear increases weight n drag
- 5. Power loading -cid- cubic inch of engine displacement CG & Landing gear -CG shifts :combustion of fuel -types of LG- -tricycle-front wheel steerable -tail dragger-tail wheel steerable
- 6. Landing gear dynamic Tricycle gear- -prevents nosing over -tail skid rests on the ground n CG shifts aft wheel axel then it will stay tail download -to prevent this LG shifted 5% of MAC aft CG -a very high thrust line n fuselage upsweep is needed to avoid long LG n prop. protection -crane -high tail moves wheel axel farther behind the CG requires heavy up –elevator deflection for takeoff Tail dragger – -disadvantages-nose over , liftoff prob.
- 7. Detail design To locate LG Tricycle gear Tail dragger Tread width -wheel tread is 25% of AR 6 span -Static load squat -Wheel diameter for paved runways 2 inch,grass-2.25 or 3
- 8. Nose n tail wheel design - Main LG legs -should be continuous piece of metal from wheel to wheel so that bending loads do not hv to b absorbed by fuselage