1. An aircraft which was flying straight and level, suddenly doubles its lift coefficient, while adjusting its thrust to keep its forward velocity constant. Find its upward acceleration in g’s.

2. The wing loading of an aircraft is 6000N/m ². The value of CD₀ is 0.018. The aspect ratio is 10, and the spanwise efficiency factor is 1. At an altitude where density is 0.5 kg/m³, find the speed for minimum drag.

3. An aircraft is in a coordinated turn, where it banks 45 degrees to the right, while maintaining altitude and speed. Find the load factor n.

If the speed of the aircraft is 200 m/s, find the radius of the turn.

4. Traveling at 200 m/s, an aircraft performs a coordinated turn, with the radius limited by the need to keep the g-level (load factor) below 9.0. What is the radius in meters, and what is the bank angle?

5. (a) A rocket propulsion system has a specific impulse of 390 seconds. Find the equivalent exhaust velocity in meters/ second.

(b) A turbofan engine has the following parameters: Air mass flow rate through the core of the engine: 100 kg/sec. Fuel/air ratio of the core flow: 0.03. Bypass ratio: 3. Flight speed: 280 m/s. Hot exhaust speed: 1200 m/s. Cold (fan) exhaust speed: 350 m/s. Find the thrust in Newtons, and in lbs, and also the Thrust Specific Fuel Consumption in (per hour).

6. a) The drag divergence Mach number of an aircraft is 0.88. Below that, the value of CD0 is approximately constant at 0.017. Estimate the value of CD0 at Mach 0.93.

b) The wing loading of the above aircraft is 5000 N/m2, and the spanwise efficiency factor is 0.97. The aircraft is flying at an altitude where the density is 0.4 kg/m3. Aspect Ratio is 7.5. The aircraft weight is 500,000 Newtons. Estimate the thrust required at the speed for minimum drag..

c) What was the final fuel weight fraction of your aircraft design?

d) How high should the floor of the Bridge at the terminal gate be to reach the bottom of the doorway of your aircraft? Show with a figure the dimensions of the aircraft fuselage, the placement of the door, the passenger compartment dimensions, and the height of the landing gear. Also show why the back end of the aircraft won’t hit the runway at landing.

e) At what altitude / speeds did your aircraft not have enough lift /thrust to fly?

7. The planet CGX375 has half the mass of Earth, and twice the mean radius of Earth. If a person who weighs 200lb on Earth reaches there with no change in mass, how much will that person weigh on the surface of CGX375?

8. What are the 3 basic ways of generating lift? Give one example of each.

AE 2350: Things you know by now, from the later portions of the course

1. A turbofan engine has the following parameters: Air mass flow rate through the core of the engine: 50 kg/sec. Fuel/air ratio of the core flow: 0.03. Bypass ratio: 12. Flight speed: 280 m/s. Hot exhaust speed: 800 m/s. Cold (fan) exhaust speed: 320 m/s. Find the thrust in Newtons, and in lbs, and also the Thrust Specific Fuel Consumption in (per hour).

2. A rocket engine has an equivalent exhaust velocity of 4000 m/s. Find the Specific Impulse in seconds.

3. At launch, a space vehicle has a mass of 10 million kilograms. The specific impulse of the propulsion system is 500 seconds. If the mass left over when all the fuel is gone is 100,000 kilograms, find the velocity increment achieved.

4. The planet CGX373 has half the mass of Earth, and half the mean radius of Earth. If a person who weighs 180lb on Earth reaches there with no change in mass, how much will that person weigh on the surface of CGX373?

5. Its Christmas Sale time at the Space Mall "Gwinnett", which is in Low Earth Orbit. Parking is hard to find, but there are some docking stations attached to the outer solar panels of the Mall. You are in a sub-compact SUV ( Space Utility Vehicle) which has a mass of 1000kg, including the 200kg of fuel still left after the trip from the Techwood Drive OrbitRamp. As you come up to this docking station, you are traveling 1000 m/s faster than the Gwinnett and need to slow down to park. The specific impulse of your SUV’s engine is 2000 seconds. How much fuel will have to be consumed to achieve the slow-down? In other words, will you be able to slow down enough before the fuel is all burned up and you go hurtling out of control into the wall of solar panels, which are used to light up the giant plastic Christmas Tree which is visible from Earth?

6. What are the 3 basic ways of generating lift?

7. You are comparing 2 proposed jet engine designs for your new long-range airliner. Company A is going to build an engine with a pressure ratio of 25. Company B proposes to build an engine with pressure ratio of 40. Which one will have the bettter thermal efficiency? Calculate the ideal value of thermal efficiency for each engine.

8. Further on in the Proposals, you see that Company A’s design will have air coming in at 280 m/s, and a jet exhaust velocity of 800 m/s. Company B’s design, for the same incoming air velocity, will have exhaust velocity of 400 m/s. Which engine will have the better propulsive efficiency? Calculate the values and compare.

9. How much more should the mass flow through Company B’s engine be to get as much thrust as Company A’s engine for the above conditions?

10. Company C claims that they can make their jet engine has a maximum turbine inlet temperature of 1600K. Company D has shown performance of their engine at 2000K. Which engine can fly at the higher speed? Why?

11. An AE enthusiast straps a rectangular wing (5 m span x 1m chord) on to his motorcyle, gets on and starts up. The whole contraption including the rider weighs 330 lbs. The wings have a maximum lift coefficient of 1.6. What speed must the motorcycle reach before it becomes airborne? (PLEASE DON’T TRY THIS EXPERIMENT!! YOU ARE TOO PRECIOUS!!)

12. An airplane weighing 670,000 lbs touches down on a short runway in an emergency landing. It is moving at 200 mph. Calculate the force needed (from the reverse thrust, ground brakes, air brakes, etc.) to bring the aircraft to a rest within 3000 feet. Assume that the force is constant for the duration.

13. Use the range equation in your notes to estimate the range of your designed aircraft, assuming that you carry the full payload, and start with the volume of fuel which you calculated before.

14. The leading edge of the wing of a supersonic bomber (just observed rolling out of a factory by a spy satellite) is swept at 43 degrees. Estimate the design cruise Mach number.

15. A wedge of 2 degrees included angle at its leading edge is moving through the air at zero angle of attack at Mach 2.4. Without consulting shock tables, etc., Estimate the angle of the shock emanating from the leading edge. Sketch the flow configuration (wedge, freestream flow direction, shock ), and indicate the shock angle on the picture.

Please study the earlier material, and expect some questions to be based on your design project. The School is watching your progress with great interest, and several faculty and older students have been very impressed with your work already. Please study hard for that Final. Thanks!