Small aircraft engines are usually placed under the wings or in the front of the fuselage. Engine placement selection; it depends on various factors such as aerodynamics, weight distribution, stability, maintenance and cost. Each option has its own advantages and disadvantages, but it’s hard to say which one is better.
While we can’t choose which is better, we can explain why these engine placements are different. After reading our article, you can be sure that you will understand better why small aircraft engines are mostly at the front and not on the wings.
Let’s start with the most common first: Airplanes with the engine on the wing
Wing-mounted engines are engines that are placed in compartments under the wing, usually in the thruster assembly (the propeller propels the airplane forward). We see these types of engines on big planes like Boeing. Wing-mounted engines have several advantages:
- Lower friction and noise in the propeller
- Better vision for the pilot
- Lower torque and gyroscopic effects from propeller reducing rudder input
However, wing-mounted engines also have disadvantages. For example:
- More difficult access and maintenance
- Less space for fuel tanks and cargo in the wings
- Higher risk of blade bending and flutter from engine weight and vibration
- In case of engine failure in twin-engine aircraft, asymmetrical thrust, inability to control
There are other less common engine layouts for small aircraft. An example of these are engines fitted to the rear of the fuselage or to a vertical stabilizer.
This is a rare engine placement for small aircraft, but they can be seen on some regional jets or gliders, such as the Embraer ERJ family or the Aviafiber Canard 2FL. Tail-mounted engines have some advantages over front-mounted and wing-mounted engines. For example:
- Better balance of weight distribution
- Better vision for the pilot
- Better protection from FOD (foreign object damage)
- Better airflow over the wing (aerodynamics)
- Less impact of engine noise on the cabin
The disadvantages of stern-mounted engines are:
- In case of engine failure in twin-engine aircraft, asymmetrical thrust, inability to control
- More difficult access and maintenance to the engine
- Higher risk of tail hitting the ground on landing or takeoff
- Higher center of gravity (CG) and moment of inertia affecting stability and maneuverability
- Higher risk of a possible fire spreading from the engine to the fuselage or wing
Our last and main model: Front-engined airplanes
Front-mounted engines are engines that are mounted at the front of the fuselage, usually in a tractor assembly (the propeller pulls the airplane forward). Examples of this are small single-engine or twin-engine aircraft such as the Cessna 172, Piper PA-28, Cirrus Vision Jet or Pilatus PC-12. The advantages of front-mounted engines are:
- Less friction and noise from the propeller
- Easier access to engine and maintenance
- Lower moment of inertia increasing stability and maneuverability
- Fuel tanks in the wings and more space for cargo inside the aircraft
- No risk of asymmetrical thrust in case of engine failure
- Uncomplicated controls that require less rudder input
Front-mounted engines also have some disadvantages:
- Poor vision for the pilot
- Higher risk of foreign object damage (FOD) from debris on the track
In conclusion; why are the engines mostly in the front on small planes?
As the most obvious reason, we can show the maneuverability that we have listed in the advantages items. The fact that the plane is light and its wing has an oval design also plays a big role in this, of course, but the fact that the engine weight is on the fuselage rather than on the wings balances the center of gravity.
Therefore, although they cannot fly long distances, these aircraft have excellent maneuverability at short distances. You may have noticed that this type of aircraft is mostly used for short-haul touristic trips, field spraying/irrigation trips that require quick maneuvers and not very long flight distances.
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