Chapter 6
Airplane Aerodynamics and Performance · 3 exercises
Problem 1
A 9 -cylinder engine with a bore (i.e. diameter of the piston head) of 5 inches and a stroke of 6 inches runs at \(2,200 \mathrm{RPM}\). The indicatcd mean effective pressure is 200 psi. If the brake horsepower is \(530 \mathrm{hp}\), calculate the mechanical efficiency.
4 step solution
Problem 2
An aircraft engine develops 260 BHP at 2,300 RPM and burns 21 gallons of fuel per hour. Calculate the brake thermal efficiency if the fuel has a heating value of 20,000 BTU per lbs. The unit weight of the fuel (gasoline) may be taken as \(6 \mathrm{lbs} / \mathrm{gallon.}\)
5 step solution
Problem 5
A turbojet engine is operated at standard \(20,000 \mathrm{ft}\) altitude conditions with an exit pressure of 9 psi and an exit area of 180 in'2. If \(\gamma=1.33\) and the Mach number at the exit is \(1.0\), what is the gross thrust? What percentage of the gross thrust is due to the pressure thrust?
5 step solution