Faculty of Engineering
Aerospace Department / / First Year
Introduction to Aeronautics
Sheet (1) 2008-2009
The use of neat sketches is appreciated
(1) Choose the correct answer:
1.1 The man noted for his rigid airship was:
(a) Montgolfier (b) Von Zeppelin (c) Leronardo da vinci
1.2 The basic principle of aerodynamic are discovered by:
(a) Orville Wright (b) Geroge Calyley (c) Samuel Langley
1.3 The glider pioneer is:
(a) Otto Lilinnthal (b) Wlilber wright (c)Charles
1.4 The buoyancy force acting on the balloon is due to the:
(a) uprising air currents.
(b) unbalance of the external pressure forces.
(c) differences in density between the surrounding air and the
lighter gas inside the balloon.
1.5 The dirigible flight is:
(a) Lighter-than-air and unpowered.
(b) Heavier-than-air and powered.
(c) Lighter-than-air and powered.
1.6 The forces produced by the airplane wing are:
(a) Lift and drag (b) thrust and drag (c) thrust and lift
1.7 The sail-plane flight is:
(a) Heavier-than-air and powered.
(b) Heavier-than-air and unpowered.
(c) Lighter-than-air and unpowered.
(2) Right or wrong? IF wrong. write the correct statement
2.1 The power output per unit weight of a bird is mush less
than that of a man.
2.2 Sustained powered flight was not possible in the last
Decades of the 19th century because even the unpowered
gliders were not yet.
2.3 The lift on an airplane is always directed vertically upward.
(3) Explain berifly how it was possible for Montgolfier's balloon and Charles's balloon to fly.
(4) What are the basic difference between a balloon and a dirigible.
(5) What is meant by the lift and the drag of an airfoil.
(6) A rectangle flat plate, 15 cm x 105 cm, is placed in an air stream and is inclined at an angle of 6 degrees to the air flow. The atmospheric pressure is 101325 pa. The effect of air flow is to reduce the pressure on the upper surface of the plate by 1000 pa and to increase the pressure on the lower surface by 400 pa what is the lift and drag of the flat plate?
(7) A small airplane has mass of 700 kg and a wing area 36 m2. the average pressure on the lower surface of the wing is 70kpa. What must be the average pressure on the upper surface of the wing for the airplane level flight?
(8) The resultant aerodynamic force F on a rectangle model wing is wing 150 N the airfoil section of the wing is shown in the figure.
a) What are the lift and the drag, and angle of attack?
b) Draw a neat sketch for the flow filed around the airfoil.
(9) Consider a Zeppelin dirigible, having a volume of 15000m3, flying at a velocity of 30 m/s at an altitude where the air density is 1.1117Kg/m3 . The zeppelin is at a small angle of attack such that is lift is only 3850 N.The zeppelin is flying in straight and level flight with no acceleration. Calculate the total weight of the zeppelin in tons.
(10) A 1.2 m diameter balloon weighs (empty) 1N and contains helium having a density of 0.1870 Kg/m3. The ambient air, having a density of 1.224 Kg/m3. Has a horizontal velocity of 20 Km/hr. the balloon is fastened to the ground by a 10m long weightless string which makes an angle of 60 degree with the vertical. Neglecting the air drag on the string. calculate the air drag on the balloon
(11) Draw neat sketches for three views of an airplane, indicating the names of the different components. Describe in short the functions of the main components.
(12) What are the four most important forces which act upon an airplane during flight? What are conditions of equilibrium of these four forces? Are these forces likely to alter in value and to move their line of acting during flight?
Prof. Dr. Gala B. Salem- 2 -