GWS C-47 power - RC Groups
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Oct 20, 2017, 03:50 PM
RichKat58
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Discussion

GWS C-47 power


Can anyone recommend a motor set up for a GWS C-47, would like to use 2 outrunner motors, one CCW and one CW. This would be my first twin engine set up, I know I need 2 ESC's but do I need a battery for each? or maybe 3, 1 for each motor and 1 for receiver ? Just what is the best way to do this, it's new to me.....Rich
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Oct 20, 2017, 06:36 PM
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Clive66's Avatar
Did you find a C-47 locally ?

I did this C-47 with brushless motors a year ago.
I can PM you the info on the components I used.
On outrunner motors, all you need to do is switch any 2 wires to reverse direction.
You will need different props, not motors (normal rotation & opposite rotation props)
Only need one battery (I run mine on a 3 cell 2200 mah LIPO)


Added:
Here's a diagram on the ESC wiring.
Last edited by Clive66; Oct 20, 2017 at 07:07 PM.
Oct 20, 2017, 09:02 PM
RichKat58
RichKat58's Avatar
Thanks, you can tell I'm planning on that silver 47. Give me a couple of weeks and I'll get with you. That diagram was how I thought it should work, thank you my friend.......Rich
Oct 20, 2017, 09:20 PM
Registered User
Clive66's Avatar
Quote:
Originally Posted by RichKat58
Thanks, you can tell I'm planning on that silver 47. Give me a couple of weeks and I'll get with you. That diagram was how I thought it should work, thank you my friend.......Rich
No hurry here.

A couple of other things about this plane.

I used separate servos for the Ailerons.
Also, didn't cut the ailerons all the way to the end of the wing.
I recommend cutting the ailerons approx 2 & 1/4 inches in from the end of the wings.
That still leaves more than enough aileron & helps prevent tip stalls at lower speeds.
The Elevator is huge, so I cut about 1/2 inch off mine.
Doesn't need a lot of elevator deflection either.
On the battery, all I did, is cut just enough foam out to create a friction fit with the battery (the plastic battery lid that comes with the kit isn't big enough)

I used 2 of these motors
http://www.headsuphobby.com/Emax-CF2...or_p_1297.html

These props
http://www.headsuphobby.com/GWS-6030...op_p_1296.html
http://www.headsuphobby.com/GWS-6030...op_p_1295.html

(4) 5 gram servos (I used these)
http://www.headsuphobby.com/Power-Up...vo_p_1876.html
Last edited by Clive66; Oct 20, 2017 at 09:53 PM.
Oct 20, 2017, 10:17 PM
RichKat58
RichKat58's Avatar
Very cool, thank you
It's amazing how far the cost of motors and speed controllers has dropped, back 10 or 12 years ago when I was into RC, this stuff cost 4 times as much......WOW
Oct 24, 2017, 09:05 PM
Registered User
I can attest that everything Clive66 has used and done for his C-47 is what I did too. And the set-up works great. I've built 2 of these years ago. The first one was built w/o a dedicated servo for each aileron and I cut the ailerons completely to the wingtips as per GWS instructions. The first flight has hair raising because I wasn't flying at a safe cushion altitude of say 300 ft. I was really surprised at the tip stall. Another guy at the park also had one and told me about cutting the ailerons to only about 2 1/4 - 2 1/2 before the end of the wingtip. Went home and modified it to 2 1/2 inches and it helped quite a lot.

The second build was a very similar build to Clive66. I used Hi-tech 9 gram servos, 1800 kv motors I bought from HK a few yrs prior to the build and were just sitting around, and the 6 inch counter rotating pops. I also flew it with a 2200 / 3S / 25C zippy and got about 4 minutes flight time at 60% throttle. If you haven't glue the fuse halves yet, I recommend gluing a qtr inch carbon rod from the front (behind the cockpit area to the tail. I did this and when I had a bad crash and considering how brittle GWS foam kits are, the plane survived quite well. Use the Gorilla polyurethane glue at each end of the rod. It's lightweight, strong, and adds foam when it expands so you have extra cushion. Last, when I mounted my motors on this build, I angled them slightly down. I didn't measure it but it looks like about 5-10 degrees. It seemed to helped the plane fly more level. It's a good looking plane in the air and I got many compliments when people saw it.


Quote:
Originally Posted by Clive66
No hurry here.

A couple of other things about this plane.

I used separate servos for the Ailerons.
Also, didn't cut the ailerons all the way to the end of the wing.
I recommend cutting the ailerons approx 2 & 1/4 inches in from the end of the wings.
That still leaves more than enough aileron & helps prevent tip stalls at lower speeds.
The Elevator is huge, so I cut about 1/2 inch off mine.
Doesn't need a lot of elevator deflection either.
On the battery, all I did, is cut just enough foam out to create a friction fit with the battery (the plastic battery lid that comes with the kit isn't big enough)

I used 2 of these motors
http://www.headsuphobby.com/Emax-CF2...or_p_1297.html

These props
http://www.headsuphobby.com/GWS-6030...op_p_1296.html
http://www.headsuphobby.com/GWS-6030...op_p_1295.html

(4) 5 gram servos (I used these)
http://www.headsuphobby.com/Power-Up...vo_p_1876.html
Oct 24, 2017, 10:11 PM
Registered User
Clive66's Avatar
The best way to make it fly better, without climbing when adding throttle, is to change the wing incidence, which means raising the back of the wing slightly deeper into the fuselage.
It comes with a little too much positive incidence (you can check that with an incidence meter & even see that it has too much positive, by looking at it with the wing & horizontal in place)
Obviously, that requires a fair amount of work, but it is effective (If I were to build another one, I would do that)

This plane was to designed to fly on fairly weak brushed motors & NIMH batteries, so the incidence wasn't as critical as it is when using these stronger motors.
I have no down thrust added to the motors on mine & as long as you don't use much throttle, it flies pretty good.
If you fly it with more throttle, just be ready to add some down elevator.
Adding motor down thrust will help some, but the best thing, would be to change the wing incidence.
Too much throttle with this power on takeoff, will cause it to climb real hard, so don't get heavy at all on the throttle for take off.

I built mine, with the intent of flying it with 4 other guys that I fly with (they were supposed to build one also)
Only one of those guys built it & the plan fizzled.
I put a few flights on mine at that time & haven't flown it since.
I have sooo many planes, and this one doesn't see any air time now.
Last edited by Clive66; Oct 24, 2017 at 11:00 PM.
Oct 26, 2017, 02:51 PM
Registered User
Oh btw, The flight characteristics that Clive described were exactly what I also experienced. I still remember my maiden take off. Maybe he also added some weight. On take off I apparently gave it too much throttle, too soon, and the plane shot up and I had to work fast to keep it from stalling. So I also added about 1 oz of lead in the nose to get better CG (for my taste = slightly nose heavy) and flight characteristics. I didn't use the clay putty that came in the kit, only lead. The clay takes up too my space.


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