kennydee

I've just started using Brushless motors. So far I have used the 50 dollar Hobby Lobby motor(with gearbox) and the Mini-AC. I have also begun using Li-pol cells. I have run into some problems, the 2 cell Li-pol is not quite hot enough(7.4 volts) and the 3 cell is a little too hot (11 volts). I fly mostly speed 400 sized stuff(16 to 25 ounces all up weight). It can be quite expensive, setting up a plane with Brushless gear, only to find out the match isn't quite right. I know, right now someone is going to suggest Motocalc (I'm not sure that name is right). I really don't want to get involved that much (OK, I'm just too damn lazy!). For me, the simpler, the better, that's why I build fan-fold planes (F.A.D. : Fanfold Aircraft Design). Some of the mag's are beginning to suggest motor, controller combo's. That's the kind of info I need, something that someone else has tried and had success with. There are a lot of options out there and my budget is somewhat limited. What is a good set-up for an aerobatic plane in the 20 to 30 ounce range?
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mglavin

My Feedback: (31)

You'll need to provide some specifications on the motor. Most likely you'll want to use a gear-box of some sort. I like the simplicity and inexpensive cost of the GWS stuff.

What props have you been running and how about run times?

kennydee

I've been using the Hobby Lobby MP jet motor(brushless with 26 ounces of thrust) with a 9/5 or 6 and a 10/5 or 6. The gearbox is about 4 to 1. I have to motor on both my homebuilt fan-fold(about 20 ounces) and the Hobby Lobby ThreeDee(about 25 ounces). The problem with the 2 cell LiPol(2000mah) is tepid performance. This motor is designed to perform best at about 9 volts. The three cell LiPol is too much at around 11 volts. I also have a couple of 9 cell 1950 mah nimh I use with these motors. The 2 cell LiPol gives me 10 to 15 minutes of flying time(but less power) and the 9 cell nimn gives me 8 to 10 minutes of flying time(but with more power). I have used GWS motors and gearboxes. I used the 300 a lot with the 6/1 gearbox on some very light fanfold stuff I made(about 10 ounces). I'm an intermediate flyer and I like my electrics to have good power, I can't hover yet but I can do a lot of basic aerobatics. I also have a Mini-AC(brushless with about 16 ounces of thrust) and it works well on lighter planes(10 to 16 ounces). It also performs best on about 9 to 10 volts, again the 2 cell LiPol is not enough and the 3 cell is too much. Does GWS make motor/gearbox combo's that can handle 20 ounces or more?

mglavin

My Feedback: (31)

GWS offers many gearbox/motor combos but there all standard can motored. Most of us use the drives because of the tuning flexibility/gear ratios available and cheap replacement parts...

There is not much info on the MP Jet motor, at least that I could locate. I'd suggest you try a 11/4.7 prop on 11.1 volts. I think you'll be pleased... Just to make sure you don't cook anything run the larger prop for a minute or so and come down and check and see if the motor is overheating. The added voltage will allow you to swing a larger prop and the lower pitch rating won't hurt either.

When you suggest 11.1 is to much what do you mean?

What type of props are you using? GWS and APC offer "E" props in many popular size ranges.

kennydee

Thanks for the info. All of the motors I have (both brushed and brushless) are designed for about 9 volts. I've read that the 11.1 volt 3 cell LiPol might be too much for my motors(in other words, seriously shorten motor life). I purchased a couple of 2 cell Thunderpower cells based on bad advice from the guy at the shop. He told me these packs would give me good performance on my speed 400 electrics. I get good flight times but not much power because, I assume, of the lower voltage. I'm using both GWS props and APC thin E props. I will continue to use both brushed and brushless, I just need to learn more about motor, battery pack, plane combo's. Will the GWS can motors (the 300 and 350) handle the 3 cell LiPol? By the way, I just damaged a gearbox on one of the 50 dollar MP Jet brushless motors I have. I called Hobby Lobby and discovered you can not buy a replacement gearbox for this motor. They don't recommend you run this motor direct drive(too much rpm) so the motor becomes a useless hunk of metal if you break the gearbox. You can replace the front portion of the gearbox if the bearings wear out, but you can't replace the gearbox if you break it.

mglavin

My Feedback: (31)

The 300/350 will take the voltage but there life will be significantly shortened!

Most likely you can retro-fit the MJ Jet motor into a GWS gear-drive. Unless the outside diameter is oddball... This is commonly done and presents very little effort in most cases.

I'd suggest you invest in a meter that will allow you to measure the current draw of your gearing and prop load. Astroflight, H9 and others offer devices for this sole purpose.