Pusher prop substitute

[foxkilo]

Like to find out from the experts here, what's the difference and any possible disadvantage if I substitute a pusher prop with a normal 'puller' prop mounted facing forward (i.e. the puller prop is now 'pushing' the motor and airplane forward)??

I'm using this arrangement now, and it seems to work, so wondering what's the need to have a dedicated-by-design pusher prop??

[blushoes]

Like to find out from the experts here, what's the difference and any possible disadvantage if I substitute a pusher prop with a normal 'puller' prop mounted facing forward (i.e. the puller prop is now 'pushing' the motor and airplane forward)??

I'm using this arrangement now, and it seems to work, so wondering what's the need to have a dedicated-by-design pusher prop??

i'm no expert. i think pusher and puller, difference is the pitch.
one is positive, one is negative pitch.

cos motors are in generally supposed to spin anti clockwise (if u look
at the motor facing u). so a pusher prop and puller prop will throw
thrust in opposite directions for the same anti clockwise spin of motor.

[foxkilo]

i'm no expert. i think pusher and puller, difference is the pitch.
one is positive, one is negative pitch.

cos motors are in generally supposed to spin anti clockwise (if u look
at the motor facing u). so a pusher prop and puller prop will throw
thrust in opposite directions for the same anti clockwise spin of motor.

Well my airplane is happily flying, so thrust must've still been in the correct direction!

...Maybe I should clarify, here's how I do it:

The motor is facing the rear of the airplane, in pusher arrangement. The puller prop is then mounted on the motor shaft, oriented FORWARD (so it looks like the prop has been mounted in reverse...).

So now when the motor spins CW (easily done by swapping two of the three motor connections), the puller prop provides thrust in the usual direction - except that instead of pulling an airplane behind it, it is now "pushing" the motor and airplane in FRONT of it.

As far as the puller prop is concerned, it is still spinning in the right sense, and providing thrust in the usual direction - so there shouldn't be any loss in function or efficiency. So why bother to use a dedicated pusher prop, is my question???

[Sunstorm]

hey fellas;

the reason that there are still pusher props around is that ;

long time ago, brushed motors were the standard and they can only turn efficiently in 1 direction

hence there is pusher props

also IIRC nitro engines also turn 1 direction only

so therefore there is pusher props

[foxkilo]

That's a possible ANSWER! Surely it has to be some "historical" reason, or outside the scope of electric flight!

[edmond22]

hey fellas;

the reason that there are still pusher props around is that ;

long time ago, brushed motors were the standard and they can only turn efficiently in 1 direction

hence there is pusher props

also IIRC nitro engines also turn 1 direction only

so therefore there is pusher props

Also to add on what SunStorm said,

The direction in which the propeller nut tightens keeps the propeller nut from loosening when the motor is running, so you will want to keep it in the right direction spin that tightens, hence the need for the right propellor to maintain that.

[Tony]

The is no difference if your motor can turn equally well in either direction eg. brushless motor. You will have to note however, that your plane may have the motor thrust line already canted (right or left thrust) to counter the effect of torque with the prop turning in a particular direction. If so, and you then run the motor in reverse, it may be necessary to reverse the thrust line accordingly as the torque effect will be working in the opposite direction.

[foxkilo]

Thanks, all Learned something new... considerations about the nut tightening direction and the motor thrust angle.

[Blackite207]

Guys there is a very big difference between the pusher and puller...And it has nothing to do with pitch or spinning direction. It is in the chararistics in flight.

The pusher prop acts very like a jet. There is little if no airflow over the control surfaces when the aircraft is stationary so in order to control the plane it needs to be moving fast.

The puller prop has its propwash over the rudder and elevator and to a smaller extent, the wing, so even when it is stationary you do have some control.... even more at low speeds.

Cheers!

[Tony]

Your point is noted and valid with regards to air flow, however, I think the original question was about swapping a pusher prop with a tractor prop. Presumbly, the motor position will remain unchanged.