Summary As smaller aircraft do not have the

Summary

This case analysis evaluates the placement of the different
engines that can be found in the aircraft design. As the placement of the
engines has a very big impact on the aircraft performance. Therefore, this case
analysis will evaluate how the placement of the engines will influences the
aircraft in many ways. For instance, safety, structural weight, drag, control,
maximum lift, propulsive ef?ciency, maintainability, and aircraft growth
potential.

 

Significance
of the Problem

Everyone’s
surely has their own view and reason on the different placement of the engines
in the aircraft design. For instance, wing-mounted engines, aft fuselage engine
placement, and three engine designs.

 

Alternative
Action 1

Wing-mounted
engines normally can seem using on larger aircraft.

 

Advantages

Such
engines placement will help to minimum the parasite drags and probably minimum
the weight. Engines are quite heavy therefore placing them in the correct
position will help to keep the balance of the aircraft, so that the aircraft
won’t tend to pitch down or up during flight. In a situation where the engine failure,
the inboard location will help to minimize the yaw moment of the aircraft due
to the asymmetric thrust.

Disadvantages

This
kind of engine placement poses as a threat to the basic wing structure because
in an event if a blade or turbine disk failure, it will result in very
difficult to maximize the inlet efficiency and making accessibility for the
engineers on the ground to perform the maintenance much more difficult. In an
event of making improvement to the existing engine design. For instance, increase
engine to larger diameter in the later date, designers and engineers will have
to redesigned and rebuild the whole entire wing. The point of placing the
engine at the correct position will help to keep the balance of the aircraft,
therefore it is a challenge that the designers face during the design phase of
the aircraft to determine the position of the engine if not it will affect the
balance of the aircraft.

Alternative
Action 2

Aft
fuselage engine placement normally can seem using on smaller aircraft. As
smaller aircraft do not have the extra space for the placement of the engines
under the wing and still maintain it adequate wing nacelle and nacelle-ground
clearances. Therefore, the next most suitable location will be aft fuselage.

Advantages

This
kind of engine placement will result in having higher CLmax due to the
elimination of the exhaust-flap interference and wing-pylon that why flap
cut-outs are not required. Which also minimize the drag experience that
generally occurs in the critical part of the taking off climb phase due to the
eliminating of the wing pylon interference. In an event of engine failure, the
asymmetric yaw will be much less due to the engine close to the fuselage.

Disadvantages

One of the main problem for this particular type of engine
placement is that the aircraft will face much more difficulty in balancing and
require generally a larger tail to do so due to the center of gravity (CG) of
the aircraft had been moved to aft. Which results in the center of gravity (CG)
to be well behind in its payload. Thus, this kind of engine placement aircraft
will require the much high enter of gravity (CG) range. As aft fuselage mounted
engines will help in the reduction of the rolling moment. Therefore, the
significant rolling moment that created by the asymmetric stalling could be a
disadvantage that resulting in an excessive roll rate during the stall.

Alternative
Action 3

Three
engine designs placement is considered to be the second generation of the jet
airliners because of the innovative engine locations which include the
advancement of the turbofan technology. Therefore, we can find this type of
engine placement in both middle and small size aircraft as large aircraft
requires much strong engine power.

Advantages

This kind of engine placement will be much lighter in weight
due to the number of engines being used on the aircraft. This design also helps
to reduce in the drag experience, effectiveness in the reverser, and give the
engineers much bigger space in the maintenance of the engines.

Disadvantages

Three
engines design placement will result in a small inlet loss due to the length of
the inlet and there will be an increase in fin structural weight in order to
support the three engines. As fuel efficiency may be another problem in this
type of design because three engines designed aircraft will normally consume
much more fuel than a normal twin engine designed aircraft.

 

Recommendation

This case analysis shows that every single engine placement
design done on the aircraft have their own possible with advantages and
disadvantages. For me, I think that wing-mounted engines are the best designs
among the three because it helps in the balancing of the aircraft and
preventing the aircraft wings from bending upwards due to the incoming winds.
However, when removing the weight of the engine from the wings, it means that
much more strength and consideration has to be put into the wings structure in
order to prevent it from bending upwards during flight like a piece of paper.
One of the main problem I think that the design teams will face when designing
this particular engine placement will be the position of the engines, if this
is not done properly it will have a very big impact on the aircraft balance. I
will recommend that the design team to work hand in hand with the engineers to
do couples of tests to find out the best position for the engines before
building the real one.