Sample Aviation Coursework Paper on (SFTY 335) – Questions Sheet

(SFTY 335) – Questions Sheet

Q. 1

Load factor (n) = 1/Cos ᴓ

Degree(ᴓ)G –load
10(1.02)g
20(1.06)g
60(2)g
70(2.92)g
80(5.76)g

Q. 2

In a constant altitude, the load factor is the result of two forces which are; gravity and centrifugal force (Chen et al, 2017). For a given bank angle, the rate of turn is inversely proportional to the airspeed hence the higher the airspeed, the lower the rate of turn. In this case, increasing the g-load sharply over the 80 degrees mark will impart too much load on the aircraft and hence can damage it.

Q. 3

The load factor is the ratio of the lift of an aircraft to its weight and depicts the stress (“load”) subjected to the structure of an airplane. In as much as the ratio is dimensionless, it is traditionally given a unit g. A load factor of one (1) depicts a scenario of a flight in a straight and level whereby lift is equal to the weight. A load factors of less than 1 is a negative g load and is a result of wind gusts or maneuvers. A negative factor can be achieved when a plane is flown upside-down during extreme banking maneuvers or when a plane hits big air pockets.

Q. 4

A Vg diagram depicts the flight operating strength of an aircraft. In the Vg diagram, the normal operating range is the region of the graph whereby the plane flies at level flight of 1g.

Q. 5

Fighter airplanes fly at greater speeds than normal passenger airplanes. As such, they need an additional area on the Vg diagram for their better performance (Chen et al, 2017). An example of extreme maneuvers done by fighter planes include extreme banking and inverted flying when in combat.

Q. 6

“I” sections are designed to be beams while “H” piles are designed to be columns. Particularly, “H” piles are made to be able to take axial forces while “I” sections are made to be beams which bend in a single direction. As such, if ‘I’ beams are used in the ‘H’ form, they will be heavier than an ‘I’ beam which can take the same load.

Q. 7

The spars (beams) are made of steel with enough strength to support the wing as well as the airplane’s aerodynamic and landing loads. These spars are the main structural members of a wing and are made to support all distributed loads for a given plane (Xu et al, 2015).

Q. 8

The neutral axis is the axis through a beam whereby there is neither compression nor tension hence the stress is zero.

Q. 9

I¯=1/2bh3 where: b= the base or width of the beam and, h=the height of the beam.

For beam 1 with breadth 0.250 and depth 0.150,

I¯=1/2 *0.250*0.1503

 =1/2*0.250*0.003375

=0.00042187

Q. 10

From a structural point of view, an engine mounted above the wing is unstable since the force of gravity acts on it and it exerts more force on the wing especially during airplane maneuvers (Xu et al, 2015). This aspect increases the stress values on the wings than in a scenario whereby the engine is mounted below the wing.

Q. 11

Moment of Inertia depicts the “second moment of area” whose units are m^2 * m * m. Hence the units for an ‘I’ value take the m4 notation.

Q. 12

The type of stress within the section beyond the last engine is the torsion. This is the stress produced by an airplane’s engine crankshaft during the period when the engine is running.

References

Chen, X. S., Lam, D. W. T., Wong, G., Zhai, C. R., & Ng, J. Y. (2017). Design, Development And Fabrication Of Aircraft Maintenance Jig. Retrieved June 7, 2018 from; https://dspace.lib.sp.edu.sg/xmlui/handle/get/16560

Xu, X., Chen, S., Li, G., Wang, S., & Li, Y. (2015, April). Construction of MBD-Based Three-Dimensional Process Design Platform for Aircraft Manufacturing. In International Conference on Advances in Mechanical Engineering and Industrial Informatics. Atlantis Press.