In propeller driven plane there are two noticeable configuration. Front nose driven propeller or known as "Tractor" which pull the plane forwards. Another one is a read driven propeller where the motor and prop nose pointed rear ward giving push thrust, this are called "Pusher" prop. So what are their significant difference in performance between two of this configuration? These factor are most popular debated among R/C flight modeler in the internet and yet have not come out and idea which works great in performance or vice verso because the problem is not one of them even fully experience or try max out their uses. As you know in side the website if flown bunch of these two setup and i can tell you they do have their differences and purposes which ultimately decide which best for your next flying platform.
But first before i continue discuss about it let me show you some of my FPV "selfie" video that feature both "Tractor" and "Pusher" setup. Watch them and see the difference between them.
- Youtube: FPV P-51D Mustang - external view (Tractor)
- Youtube: FPV Drifter Ultralight - external view (Pusher)
- Youtube: FPV Pitts Special - external view (Tractor)
Done watching? Good! Did you notice any differences?.................... Drifter Ultralight (Pusher) are noisy right? Why? Let find out why.
TRACTOR
Tractor configuration is where the propeller and motor are located at very front of the nose or most front of the wing where it "pulls" the plane forward like a tractor. This is most traditional way to propel the plane since the early days of aviation technology.
Pros:
- Tractor are silent, they don't make much noise unlike the pusher because the front propeller received direct "clean" un-disturbed airflow from the front causing the air to flow through the blades more smoothly and balanced on each side of the propeller blade, which is why they don't make much noise due to low vibration incident to the blade.
- The clean air then pushes to the back along the main wings giving more direct air flow to the aileron control, elevator and rudder control allow better maneuverability at low speed because each control surface receive constant steady airflow from the propellers even if the forward airspeed is at minimum. That's why tractor planes such as YAK, EDGE 250, PITTS SPECIAL and other aerobatic/stunts plane could do fact tight slow maneuvers because each control always received clean airflow from the props. Tricks like Prop hangs, knife edge, snap rolls and other 3D moves are easily executed on Tractors.
- In FPV flights Tractor configuration allows pilot to visually gauge which rpm throttle should be apply and get the right rotation per-thurst. You don't have to put an FPV earphone to hear the motor rpm level if it goes too much, rowdy or if the throttle was adequate. Tractor give a good throttle visual aide.
- On the performance side Tractor setup on FPV/UAV models doesn't require long take off and landing space. Some are almost STOL (Short Take Off and Landing) capable when proper wing surface control received full amount of airflow along the main wings.
Cons:
- The cockpit view on Tractor driven plane aren't much an appealing for forward viewing because the front are mostly obstructed my big propellers.
- In FPV flight majority pilot dislike it because it obstruct camera viewing especially during recording.
- Scale plane with bigger and heavy propellers such as the famous F4U Corsair have huge inertial weight on its propeller blade that it will "torque roll" the whole plane fuselage if suddenly take off without getting enough airspeed to allow airflow around the wings to counter the effect. The same effect applied when helicopter flown without functional tail rotor.
Application:
- Tractor are good for 3D/F3P flight application for slow moving aerobatics and agility.
- Excellent for long range, low power and endurance flight.
- Stealth flight because of its silent attributes. (Spy drone).
PUSHER
Pusher configuration are well known for fast plane setup. They are usually equipped with smaller and narrow propeller to make it its high rpm motor. Located and pointed to the rear the propeller pusher the air out to the back hence called "Pusher".
Pros:
- Pusher plane are usually ideal for FPV because the propeller are located at the back and doesn't obstruct the camera forward viewing and recording.
- They are very popular for hand launched and belly landing style flying platform and pilot can also safely catch these plane during landing in the air because there's nothing in the nose to hurt their hands.
Cons:
- Pusher are definitely a very noisy setup because pusher propellers received "un-clean" or disturbed airflow that run through various surfaces on the airframe before it reached to the propeller blades. Clean forward air bump along the fuselage nose, wind shields, cameras, wing leading edges, and other surfaces causing unstable ripple of wavy air and then hit the propeller blades at final destination. The uneven wave of "disturbed" air from slammed from various sides causes each propeller blade to flex/vibrate unevenly throughout the RPM causes noisy pitching sounds. Its like different amplitude of wave in the ocean hitting differently on each side of your boat.
- Because of being slammed by different force of airflow into the blades pusher airframe owner always uses hard type composite blade such as APC type blade to counter flexy pitch blade problem thus reduce bleed of thrust performance. Smaller blade pitch and length help to minimized the problem and ease fast rotation to generate thrust.
- Pusher only pushes airflow through elevator and rudder surface control because the pusher motor usually located behind the main wing. To take off pusher plane have to speed forward fast to get more wind/airflow under the wings thus requires longer runway to take off and landing. However this can be compensated by having a bigger and longer wingspan to generate short lift off capability but with added weight for extra inch of wing extension. This can be seen on glider type pusher props.
Application:
- Excellent for delta shaped wing for fast performance flight, usually accompanied with smaller pitch and length props for FPV.
- Good for belly lander on grass because caught the platform in the air during landing by hand because nothing in front of the nose to cause injury.