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technical specs motors and props

#1
I know it is repeated all over the net , but still seems inconclusive and sometimes inaccurate.
I understand that when installing a motor and prop on a plane in a tractor configuration you have the ability to reverse the spinning direction, but I want to understand the terms as read when purchasing. Please correct me here. Please don't add to confusion by talking about reversing wires.

Perspective of reader to the motor when determing spin direction- the shaft end with threads facing toward the reader.

Shaft threads are right hand or left hand tightening. Standard thread direction in the US is right meaning right to tight, left to loose.

CW (clockwise) and CCW (counter clockwise) describe the spinning direction not the thread direction of the shaft based on reader perspective .

Motors that do not list a direction are typically CCW?

Threads on shaft tighten in opposite direction on spin direction (as designed and described , not confused with as installed and electrified )

CCW motors will have right hand threads.

Propellers described as spin direction not thread direction. And lettering / numbering on prop facing reader would be the perspective for direction.

Not positive how to convert the LH (left hand) RH (right hand) descriptions sometimes on props to CCW vs CW.

Not sure what the designed direction of a prop is when no direction is listed.

It seems that pusher vs puller is a plane configuration, not a technical spec

Can be very frustrating trying to purchase props when there is no local hobby shop to lay hands on...
 

CarolineTyler

Well-known member
#2
Perspective of reader to the motor to determine spin direction- the shaft end with threads facing toward the reader. YES

Shaft threads are right hand or left hand tightening. Standard thread direction in the US is right meaning right to tight, left to loose.

CW (clockwise) and CCW (counter clockwise) describe the spinning direction not the thread direction of the shaft based on reader perspective. YES

Motors that do not list a direction are typically CCW? YES but largely irrelevant for electric motors

Threads on shaft tighten in opposite direction on spin direction (as designed and described , not confused with as installed and electrified ) YES – so a nut will generally self tighten when the motor starts spinning

CCW motors will have right hand threads. YES

Propellers described as spin direction not thread direction. And lettering / numbering on prop facing reader would be the perspective for direction. YES

Not positive how to convert the LH (left hand) RH (right hand) descriptions sometimes on props to CCW vs CW. ??? not sure if this is a question

Not sure what the designed direction of a prop is when no direction is listed. The prop will have a sharper thin trailing edge and a blunter thicker leading edge. This will tell you the designed direction of spin of the prop

It seems that pusher vs puller is a plane configuration, not a technical spec YES – PUSHER PROPS stem from fuel engines that are made to spin only in one direction so putting them at the rear of the plane required a reversed pusher prop to work
 
#3
Thank you very much. And yes this is a question and probably the one that frustrated me the most.

Not positive how to convert the LH (left hand) RH (right hand) descriptions sometimes on props to CCW vs CW.

I went to apc Website looking at 6x3 props and they were listed as RH or LH. ... and it was getting late at night.

I never fully trust the pictures of some items on the Web so I was afraid to commit.
 
#4
Or I read this last night which added to my confusion since the person changed perspective from what many hold as standard? ------

A standard (RH) propeller mounted on the nose will spin clockwise as viewed from the cockpit. It's best to use this type for a single-prop aircraft because, well, it's standard. Rotation direction will affect torque roll, P-factor, and thrust angle conditions, and it's just easier if your model's characteristics match up with others in this department. This is the type of prop you should use.

A reverse-pitch (also reverse-rotation, or LH) prop will spin counter-clockwise as viewed from the cockpit. The main use for these props is to balance torque on a twin setup. They're occasionally referred to as "pusher" props, which is a pointless, obsolete, and confusing term. They work in exactly the same way as standard props, but their pitch is "mirrored".
 

CarolineTyler

Well-known member
#5
Or I read this last night which added to my confusion since the person changed perspective from what many hold as standard? ------

A standard (RH) propeller mounted on the nose will spin clockwise as viewed from the cockpit. It's best to use this type for a single-prop aircraft because, well, it's standard. Rotation direction will affect torque roll, P-factor, and thrust angle conditions, and it's just easier if your model's characteristics match up with others in this department. This is the type of prop you should use.

A reverse-pitch (also reverse-rotation, or LH) prop will spin counter-clockwise as viewed from the cockpit. The main use for these props is to balance torque on a twin setup. They're occasionally referred to as "pusher" props, which is a pointless, obsolete, and confusing term. They work in exactly the same way as standard props, but their pitch is "mirrored".
That was all correct - I've not heard of props being described as handed, usually clockwise or anticlockwise (counter clockwise in US speak )
 

Merv

Well-known member
#9
The term tractor and pusher prop are throw backs to the glow engine day. You could not easily reverse the spin of a glow engine. It took a new crankshaft, you had to change the port timing to make it run well. It was far easier to change the pitch of the prop.

You can easily reverse the spin of an electric motor, just switch any two of the three wires. With a plane, just tighten the nut and you will be fine. No so with a quad, the motor is starting and stopping multiple times per second. Which will eventually work the prop nut lose, if you run it “backwards”.