AIRPLANE PERFORMANCE HOMEWORK

4. Consider an a/p with the following data: wing span=20 ft (small airplane), wing planform area =38 ft2 , C L max=1.6, Weight take off =1000 lb, Fuel capacity= 55 gal, Turbojet engine with max thrust at sea level of 200 lb and sfc=1.3 lb/(lb-h), approach angle while landing 3 deg, Drag polar: CD=0.02+0.062*CL2

Assume CLmax =1.6, clearance height of 35 ft, coefficient of rolling friction = 0.04 and height of the wing above the ground (sea level) during ground roll is 1.5 ft (Kuc=4.5x10-5, e=0.9).

(a) (3 points) Calculate the take-off distance at sea level. Use ex 6.6 as a guide.

(b) (2 point) If the CLmax is increased to 1.8, what is the change in the takeoff distance?

5. Consider an a/p with the following data: wing span=20 ft (small airplane), wing Planform Area =38 ft2 , C L max=1.6, Weight take off =1000 lb, Fuel capacity= 55 gal, Turbojet engine with max thrust at sea level of 200 lb and sfc=1.3 lb/(lb-h), approach angle while landing 3 deg

Drag polar: CD=0.02+0.062*CL2

Assume CLmax=1.6, clearance height of 35 ft, coefficient of rolling friction with braking= 0.4 and height of the wing above the ground (sea level) during ground roll is 1.5 ft. Remember this is a small aircraft. wing Planform Area =38 ft2

(a) (3 points) Calculate the landing distance at sea level. Use 6.7 as a guide (Kuc=4.510-5, e=0.9, G=0.588, CL=0.1 (for ground roll).

(b) (2 point) CLmax is increased to 1.8, what is the change in the landing distance

6. Predator airplane has the following characteristics:

Weight 2250 lbs, Length 27 ft, Wingspan=48.7 ft, Reference Area=123.3 sq ft

Cruise Speed=140 mph =140*(88/60) ft/sec=205.33 ft/sec, Altitude =25,000 ft, Assume e1 (or e) = 0.95, Cd0=0.08, density =1.0663x10-3 slugs/ft3

Let the predator be accelerating and doing climb up-roll maneuver cd0=0.08.

Let thrust is at an angle () of 5 o to the flight path, flight path is at an angle (of 5 o to the horizontal, roll angle () =10 o, the thrust (T) of the engine is 500 lbs during climb up, r1=10,000 ft, r2=10,000 ft

Calculate the lift for the case in which acceleration component is in the direction perpendicular to the flight path in a plane parallel to the surface of the earth (1 point)