|
Title: Puller prop pusher prop Post by: docnayeem on January 12, 2014, 11:18:14 AM Hello every one ....
Need help .... Props ... Pusher and puller ... In an electric setup can a puller be used as a pusher ? I guess yes I have read it on the net too to mount it reverse but does it give the same efficiency and thrust ? And design wise what is the main difference in a puller and pusher prop. Knowledgeable people ... Awaiting replies Thanks in advance Title: Re: Puller prop pusher prop Post by: Priyum on January 12, 2014, 08:12:36 PM Yes it can be done,just reverse the prop and change 2 out of 3 wires of the motor to esc and your'e done!
Title: Re: Puller prop pusher prop Post by: anwar on January 12, 2014, 08:16:27 PM Reversing a prop does not work that way... otherwise there would only be one type of props !
http://www.rcindia.org/rc-general-topics/basic-aerodynamics-for-rc-flying/msg72909/#msg72909 (http://www.rcindia.org/rc-general-topics/basic-aerodynamics-for-rc-flying/msg72909/#msg72909) It will be less efficient when it is all said and done. Title: Re: Puller prop pusher prop Post by: sushil_anand on January 13, 2014, 11:52:15 AM Not true, Anwar. Reversing the prop AND rotation will will be as "normal". Think of it as just moving the motor from the rear to the front (of the prop)!
Title: Re: Puller prop pusher prop Post by: anwar on January 13, 2014, 12:49:24 PM I think you misread my message. What I said (or intended) was that reversing the prop does nothing, and reversing the motor will result in an inefficient operation as the leading edge of the propeller is not the leading edge any more.
Title: Re: Puller prop pusher prop Post by: girishsarwal on January 13, 2014, 02:32:42 PM Anwar sir, I tend to agree with sushil sir. Reversing the prop will not have any affect on the pitch angle but will mirror the leading edge; This followed by a toggle in rotation will give the desired effect of converting the puller into a pusher, the LE will still be the LE. The idea of LH and RH props is more suited for multirotors and multi engine airplanes, where all of them have to throw air in the same direction with the counter rotation preserved
Title: Re: Puller prop pusher prop Post by: K K Iyer on January 13, 2014, 02:40:17 PM @anwar sir,
With due respect, let's do this in 3 steps. 1. Turn the motor around so it faces backward 2. Interchange wires to reverse direction of rotation 3. Reverse the prop so that the 'leading edge' leads Seen from behind, the prop orientation and direction of rotation will be identical in the tractor and pusher configurations. (Whether the motor and cowl create more drag when ahead of / behind the prop is a different question....) Title: Re: Post by: docnayeem on January 13, 2014, 02:43:53 PM I totally agree with Mr. K K Iyer ... From what literature I got to read ... There is no design difference in a pusher and puller prop ... In an electric setup
In a nitro or glow setup where the direction of rotation cannot be changed the prop has to be a pusher prop with an inverted helix Title: Re: Puller prop pusher prop Post by: anwar on January 13, 2014, 02:55:44 PM Yes, you are right. The combined action does preserve the leading edge.
I was confused for a moment, and stand corrected. We had an incident at the field where someone had used a prop with the wrong leading edge, and his Floater/Bixler had severe thrust issues. I hope my getting geriatric helps you avoid the leading edge problem when you mount your props ! :) The same thing was discussed here : http://www.rcindia.org/beginners-zone/pusher-configuration/ (http://www.rcindia.org/beginners-zone/pusher-configuration/) Title: Re: Post by: docnayeem on January 13, 2014, 03:01:30 PM I knowledge is updated and confusion cleared thanks to all the experienced people around ....
|