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Old Sep 28, 2011, 06:04 AM
Registered User
New Zealand, Wellington, Lower Hutt
Joined Sep 2011
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Pusher prop vs Standard prop

Hi everyone, complete newbie question here.

I've got a foamie wing that I'm keen to mount a motor on in a pusher config. I'm looking into the correct prop to buy for it, and am wondering if I need to buy a pusher prop for it?

I don't have a prop in front of me at the moment so I can't quite visualise what's going to happen. Presumably to use a standard prop you'd have to have the motor spinning "backwards". Is that correct? I assume as it's an electric motor it should run equally well forwards or backwards?

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Old Sep 28, 2011, 06:24 AM
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Azarr's Avatar
Dayton Intl, Ohio, United States
Joined Jan 2000
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[QUOTE=DaveTheKiwi

I don't have a prop in front of me at the moment so I can't quite visualise what's going to happen. Presumably to use a standard prop you'd have to have the motor spinning "backwards". Is that correct? I assume as it's an electric motor it should run equally well forwards or backwards?

[/QUOTE]

Welcome to RC Groups. Yes, you are correct. You reverse the motor and install the prop with the convex side facing the direction of flight. The reverse pitch props for electric flight are mainly used for counter rotating motors on multi engines to eliminate torque, on contra rotating motors and for the mushrooming multi rotor tri/quad/octo copter market.

That being said, there's no reason not to use a reverse pitch prop if you have one, just don't reverse the motor.

Azarr
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Last edited by Azarr; Sep 28, 2011 at 06:34 AM.
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Old Sep 28, 2011, 08:45 AM
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Staffs, UK
Joined Nov 2003
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That's it. For a pusher configuration almost everyone simply uses a standard (tractor) prop mounted what would normally be "backwards" (i.e. with the convex side towards the motor)and then reverses the rotation of the motor. Brushless motors in particular will run equally well in either direct.

Steve
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Old Sep 28, 2011, 11:27 PM
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Awesome. Thanks for the info!
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Old Sep 28, 2011, 11:38 PM
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United States, NC, Bear Grass
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Tractor style (puller) the numbers on the prop face forward.
Pusher style the numbers on the prop face forward.
If looking at the plane from the front your motor needs to turn counterclockwise in both pusher and puller.
Just make sure the prop faces numbers forward and reverse 2 of the wires to make your motor turn counterclockwise. It's that easy. You don't need a counter-rotating prop.
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Old Sep 29, 2011, 01:19 AM
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United States, CA, Ontario
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Not correct , they will turn different directions ...looking towards the front , puller will turn clockwise , pusher will turn counter-clockwise

Ask me how i know (see pic)
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Old Sep 29, 2011, 04:03 AM
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Staffs, UK
Joined Nov 2003
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Another name for a "pusher" prop is a reverse rotation prop. It is specifically designed to turn in the opposite direction to a "normal" prop.

BTW a tractor/normal prop turns clockwise and a pusher prop turns anti/counter-clockwise when you're looking FROM the front of the plane TOWARDS the prop (which may well be what you meant ).

Late correction - I got it the wrong way round again (where's the "embarrassed" smiley when you need it ?). Thanks Dennis and Azarr. Must watch my clocks more carefully in future.

Steve
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Old Sep 29, 2011, 05:33 AM
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Dayton Intl, Ohio, United States
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As you can see, this is confusing, even for seasoned modelers. Dennis Everett is correct. Convention has it that most references to our models are as if we are in the cockpit looking forward. For instance, that way, we all know which is the right aileron or right rudder. If someone says "give right aileron" we don't ask if we're looking from the front or the back.

In this case the convex side of the prop always faces the direction of flight, the tractor propeller would move clockwise and the reverse pitch (pusher) counter clockwise regardless of whether the prop is located on the front or back.

Azarr

Edit: The "pusher" (actually reverse pitch) props originally were developed because reversing the direction of a glow engine is impractical. In the days of only glow motors reverse pitch props were required to fly a rear engined plane. The modern Brushless motor runs well in either direction.
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Old Sep 29, 2011, 08:15 AM
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United States, NC, Bear Grass
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Quote:
Originally Posted by Dennis Everett View Post
Not correct , they will turn different directions ...looking towards the front , puller will turn clockwise , pusher will turn counter-clockwise

Ask me how i know (see pic)
I really need you to tell me how you know b/c I am 101% sure that I am correct.
If you look at it from the rear both props will be turning clockwise. If you look at it from the front both props will be turning counterclockwise.
The motors in the different configurations do turn opposite of each other but we aren't looking at which way the motor is turning. We are paying attention to the prop in this instance. This is the easiest way for someone new to understand this.
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Old Sep 29, 2011, 08:16 AM
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United States, NC, Bear Grass
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Quote:
Originally Posted by Azarr View Post
As you can see, this is confusing, even for seasoned modelers. Dennis Everett is correct. Convention has it that most references to our models are as if we are in the cockpit looking forward. For instance, that way, we all know which is the right aileron or right rudder. If someone says "give right aileron" we don't ask if we're looking from the front or the back.

In this case the convex side of the prop always faces the direction of flight, the tractor propeller would move clockwise and the reverse pitch (pusher) counter clockwise regardless of whether the prop is located on the front or back.

Azarr

Edit: The "pusher" (actually reverse pitch) props originally were developed because reversing the direction of a glow engine is impractical. In the days of only glow motors reverse pitch props were required to fly a rear engined plane. The modern Brushless motor runs well in either direction.
I believe we were talking about using the same prop as a pusher or puller. Not using a counter rotating prop.
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Old Sep 29, 2011, 09:14 AM
Jack
USA, ME, Ellsworth
Joined May 2008
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One is saying viewed from the plane (i.e., the pilot's seat), the other is saying viewed from in front of the plane, so they are both describing the same rotation from two different places. And they want to argue about it?

Jack
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Old Sep 29, 2011, 09:29 AM
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Rich in ILM's Avatar
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Quote:
Originally Posted by jackerbes View Post
One is saying viewed from the plane (i.e., the pilot's seat), the other is saying viewed from in front of the plane, so they are both describing the same rotation from two different places. And they want to argue about it?

Jack
My simple way to keep myself sane. Props must always have their lettering facing into the direction of flight. Motors are, normally, always set up to turn counter clockwise. To use a standard prop on a motor on the back of a plane just change the rotation (2 out of 3 wire esc switch) to clockwise and make sure the prop lettering is facing forward. I always do this as there is a much larger selection of standard props than pusher.
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Old Sep 29, 2011, 10:47 AM
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Moab, Utah, USA
Joined Apr 2003
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If you go back and read their posts carefully you will see that the confusion lies in the fact that one is using a regular pitch prop in front and a reverse pitch prop in back. The other is using regular pitch props in both locations. The one using the regular pitch prop worded his reply in such a way that if not read carefully it leads one to think he is using a reverse pitch prop in the rear.

Larry
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Old Sep 29, 2011, 11:45 AM
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United States, CA, Ontario
Joined Mar 2002
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When i set up the Falcon above my local hobbyshop did have both pusher and tractor props in stock (13x8-3 blade), but like was said above , pushers are harder to find , so if the prop i bought didnt work so good trying to find another one wouldnt be so easy , so i went with the tractor .
Ive since changed it to a cut down apc 12x12 which works much better(near same amp draw and better speed )...
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Old Sep 29, 2011, 01:25 PM
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United States, NC, Bear Grass
Joined Jul 2011
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Maybe this vid will sum it all up.
Tractor Prop To Pusher Prop Conversion (5 min 19 sec)
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