Scratcher

1. If two of the same type/strength electric motors are turning the same gear, do the motors work together for more efficiency or do they work against each other? 2. Do electric motors work just as efficient in reverse as they do in forward? 3. Can anyone tell me where I can find a contra rotating prop assembly or gearbox for RC airplane props? Thanks!

DBCherry

My Feedback: (4)

Two motors are often run together on the same gearbox, there's even a company (or two) that sells these setups.

Many motors will run just as well reversed, but some motors have adjustable timing, so you have to be sure the timing is either "neutral", or set for referse operation.

Sorry, but I can't help with the other question.
Dennis-

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Here is a gear box for a motor that is forward or neutral timed http://www.maxxprod.com/mpi/mpi-10a.html I am not sure how big a motor you want. A buddy of mine has this in a little park flyer. It works find but is not very durable when the nose hits the ground first. Of course, what is? I haven't seen anything like this that will handle 2 motors though.

RandyL

My Feedback: (4)

Thinking over the gearing and direction makes my head hurt...but...here is a set up that fly a 7 pound + Telemaster. It is a gearbox with a pair of $6 each 05 can motors. It is very simple actually. Both motors run the same direction, no reverse timing issues. Motors mounted backwards and then direction is reversed with the through the gears and prop shaft which means the motors are wired to run a normally timed forward direction and the prop turns the correct direction. It is so simple I would never have figured it out!

Scratcher

Randy, thats exactly what I was looking for but have a few more questions...1. Where can you get the gears and extra shaft for the prop gear? 2. Did that setup run 2 motors on the same ESC? #. May seem like a dumb question but if they did share a ESC, does 2 motors drawing 10 amps pull 20 amps through the ESC? Thanks!

RandyL

My Feedback: (4)

Scratcher, I am by no means an e-guru.. I usually ask all my friends over on the E-zone to help with power systems but I am learning slowly.
An 05 motor will take about 30 amps max... I am using a pair of them on a single ESC ( 40 amp if I remember correctly ) and am using a 16cell pack. You have to have identical motors and a single ESC to gear them together, as I see it.
I flew the twin speed 600's for a while and currently have an Astro 40 geared motor and the same pack and ESC. I like both. The Astro 40 is simpler and stronger but the twin 600's really peaks flyers interest and increases the "fun" value!
The mounting bracket, bearings, and gears are sold as a set. I think EAM still has them..http://eam.net/ let me know if they don't. I may can get another set around here.
Go to my homepage listed below and look for the electric section, then on to the Telemaster project. I can always be reached via e-mail and that is on my homepage as well.
What type project you have in mind???

Scratcher

I dont currently have a project started, just trying to gain some knowledge on a few subjects before I sink some cash into this hobby. You guys at RCU are wonderful at answering my questions so far! So on to the next question...lol. Do all props for electric motors require a prop adapter or are there some that just push on the shaft or have a simple set screw?

RandyL

My Feedback: (4)

Scratcher, There is no need of a prop adapter so to speak.. you are just trying to find a way to mount the prop to the motor shaft and there are many ways from simple push on props to machined adapters that allow a large hole in a prop to fit a small electric motor shaft.

Scratcher

So some props fit tight enough they don't need a set screw or a dab of glue, just pop them right down onto the motor shaft and spin away? And they never slip or bore the hole loose?

RandyL

My Feedback: (4)

Yep,,, you got it. A lot of the Zaggi and various speed 280 through 400 have press on props. Seems strange but works.

Randy

Scratcher

I was needing a push on prop for a speed 600 with 3.2mm shaft...available?