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

Landing gearFore –plane characteristicsTo 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

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

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

Landing gear dynamicTricycle 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.

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

Nose n tail wheel design -Main LG legs-should be continuous

piece of metal from wheel to wheel so that bending loads do not hvto b absorbed by fuselage