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Oct 20, 2017, 02:50 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, 05:36 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 06:07 PM.
Oct 20, 2017, 08:02 PM
RichKat58
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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, 08:20 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 08:53 PM.
Oct 20, 2017, 09:17 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, 08:05 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, 09:11 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 10:00 PM.
Oct 26, 2017, 01:51 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.
Dec 23, 2017, 09:23 AM
RichKat58
RichKat58's Avatar
Got my 47 from Mr.Clive yesterday, ordered the power set up he used today. Thinking of making some more scale looking landing gear for it, at least getting some more scale tires, saw some at a Hobby Town that would look great I think, that and two leg gear would look good. Don't think I'll use the factory decals, been looking at DC3 pics on line, lots of natural metal paint jobs to choose from. I have printed my own decals before, print on card stock paper, seal with clear spray paint, and use spray contact glue to attach, so maybe a Thompson AirLines in the future.....LOL
Dec 23, 2017, 03:18 PM
Registered User
Clive66's Avatar
Rich
Looking forward to the results.
Latest blog entry: Goldberg Eagle 2
Feb 05, 2018, 07:18 PM
RichKat58
RichKat58's Avatar
Just about done with covering, now on to primer and dreaded sanding then white upper and silver overall. Should be done around spring.......LOL
May 21, 2018, 02:36 PM
Registered User
Quote:
Originally Posted by RichKat58
Just about done with covering, now on to primer and dreaded sanding then white upper and silver overall. Should be done around spring.......LOL
Okay, it's Spring so I'd be very interested in new pics to see how she looks, how the power system works and how she flies.

Btw, if you haven't added the decals yet, I'd like to offer a tip that I've been using for years. HomeDepot sells a bathroom calk/sealer made by DAP. It's water based and dries clear (even though it comes out of the tube white). Many times when I finally get around to building a plane the decal glue has aged and the decals won't stick. I put this calk on the back side of the decal, wet my finger, and spread the calk into a thin layer. After applying the decal I spread it out using a soft sponge or my finger. The calk takes overnight to dry properly but it's super elastic and when it's dry the decals don't come off. Additionally, this calk works great on acetate canopies. I used it on my GWS Focke-Wulf canopy 8 years ago and it's still in tact after hundreds of flights.
May 31, 2018, 03:10 PM
Registered User
E-Challenged's Avatar
"Canopy Glue" RC-56, etc., works well on foam models, it's water based, easy clean up with damp Q-Tip, goes on milky, dries crystal clear, stays flexible, grips well. I use it on windows and windshields as intended, plus for gluing nylon or CYA type hinges into slots, etc. Don't get glue on rotating nylon hinge parts or on hinge areas of CYA hinges.
May 31, 2018, 03:20 PM
Registered User
E-Challenged's Avatar
I bought 7 inch CW and CCW 3-bladed props from Motion RC for my Pat Tritle DC-3 . One type is for a foam B-17 that has small GWS shaft holes. I will fill hollow hubs with epoxy and drill for larger brushless motor prop adapters. I will use a single 2200mah 3S lipo and two matching Cobra motors and speed controls. Always use a good predictable duration lipo pack and land well before either speed control can go into low voltage cutoff (LVC) using your timer. Disable the BEC circuit in one speed control .
Jun 05, 2018, 03:31 PM
Registered User
Quote:
Originally Posted by E-Challenged
Disable the BEC circuit in one speed control .
Hey, E.
What is the reason for disabling the BEC on one of the ESC's on a twin motor plane like a DC-3?


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