Secondary Flight Control Surfaces and Engine Types

Published: October 08, 2019


What are secondary flight control surfaces? How many engine types are there? Flight control surfaces are devices that allows a pilot to adjust and control the aircraft’s altitude by using aerodynamics. Main control surfaces include ailerons, rudders, and elevators.

Secondary control surfaces include spoilers, flaps, slats, and air brakes. Spoilers, no not the movie or automobile kind, are often called lift dumpers as they are used to reduce lift by disrupting the airstream above the wing.

Spoilers allows glider pilots to reduce in altitude without increasing airspeed. Spoilers that are asymmetrical are referred to as spoilerons and can affect the roll of an aircraft.

secondary flight control surfaces and engine types

Flaps, on the other hand, can be found on the trailing edge of each wing near the wing roots and are used to increase effective curvature of the wing! Flaps are used to reduce stall speed due to the fact that the maximum lift coefficient is raised, hence why they are most commonly used during take off and landings!

Flaperons, or inboard ailerons, are also present in some aircrafts and behaves much like ailerons, however, these inboard ailerons may stoop lower than usual when the flaps are deployed. Therefore, flaperons will act as both a flap and an inboard aileron that controls roll.

Slats are used to reduce stalling speed by altering airflow over the wing and has got two types! Fixed or retractable slats! As the namesake says, fixed slats are fixed and are great to decelerate while retractable slats can be emerged when required only!

secondary flight control surfaces and engine types

Last, but not least, air brakes are used to increase drag and slow down the aircraft. Spoilers can be said to act as an air brake, but cannot fully take the roll of an air brake as spoilers also functions as lift-dumpers.

This is useful when an aircraft is required to descend urgently! Why is it important to slow down an aircraft? Well, without decelerating an aircraft prior to landing, problems may arise and lives may be put in danger! This is why it is important for all pilots to understand the uses of control surfaces and what their effects are.

secondary flight control surfaces and engine types

What about turbine engines? Turbine engines can be classified to 3 groups; whether the compressor is centrifugal flow, axial flow or a combination of both centrifugal and axial.

There are 4 types of aircraft engines: Turbojet, Turboprop, Turbofan, and Turboshaft. The first, in no particular order, is the turbojet which was first developed before the start of the Second World War. There are 4 sections of a turbojet engine which is the compressor, combustion chamber, turbine section, and exhaust.

The second, turboprop, drives a propeller through a reduction gear and hence, allowing optimum propeller performance at a lower speed. This can be commonly found in smaller aircrafts as it is more fuel efficient.

Thirdly, turbofan engines, can be said to be the child of turbojet and turboprop as it has the best features of both. Turbofan engine began its journey in 1941 where it was used for commercial and military aircrafts.

Turboshaft engines, on the other hand, gains most of its energy from the expanding gases that would then drive the shaft that is connected to a turbine, hence the name. Turboshaft engines can be found commonly to be used by helicopters!

secondary flight control surfaces and engine types

There are lots of advantages of turbine engines compared to other reciprocating engines, one of them being that there is less vibration from turbine engines along with increase in reliability.

In conclusion, it is important for all pilots to understand the uses of secondary flight control surfaces and engine types in order to know your aircraft better. This would, without a doubt, guide you to become a more efficient and safer pilot.


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