View Full Version : GWS Cargotrans Quad "EC-130H Compass Call" Build Thread

03-09-2006, 03:49 AM
The build is complete as of tonight, but instead of just posting a link to that "other" site, I figured I'd copy my build log here too. I will make multiple posts to kind of break it up, so bear with me. The chronology will seem a little "off" as the thread I'm copying from was three weeks total in the making.

OK, so I finally started building the kit I picked up at the AZ Electric Fly 3 weeks ago. My build will be a model of the plane I flew on when I was in the Air Force. This is the EC-130H "Compass Call" airborne jamming platform. The pic below is of tail number 1862, which is one of the few of these I have flown on.

After checking to make sure all the parts were in the kit, I began sanding off all the foam injection "dimples" and imperfections. I used 240 grit paper on a foam padded sanding block. I then cut out and hinged all the control surfaces. I will be applying the two-tone paint scheme prior to gluing all the parts together, and will touch up after final assembly and filling the cracks with spackling.

I have considered several of the modifications that have been presented in other build threads on RCG, and will most likely do the ones like stick motor mounts, relocate battery farther forward, engine wiring harness, etc. I have already removed the filler styro from the main gear wheel wells to keep the wheels from binding.

Since I will have so much extra stuff on the tail assembly, I will use carbon fiber pieces and low diameter fishing monofilament to help keep the weight down. Detailed pics will be provided during the rest of the build.

03-09-2006, 03:51 AM
I have made significant progress in this build. The next few posts will detail my build to this point. Note that I did not follow the instructions as laid out in the manual as I knew I would be tail heavy in the build. So in order to balance things out better, I would need to move the radio components around some. Namely, I would be mounting the rudder/elevator servos forward of the central bulkhead.

Step one was to sand out all of the mold marks. I also filled all indentations in the foam with lightweight spackling. Everything was sanded down to a smooth finish. I also cut and hinged all control surfaces in the initial steps.

As others have done, I removed the styrofoam from the aft section of the wheel well so that the rear tires wound not bind on landing.

03-09-2006, 03:55 AM
Next I started working on the wing. After joining the wing halves together and gluing in the carbon fiber support rod, I worked on assembling the motors. I opted for the stick mounts as described in another RCG build thread, as I too did not want to rely on the extremely thin plastic cowlings for support. I used lightweight basswood for the motor mounts, and included a block in the rear to act as a motor stop.

Jeff Hunter (Jarhead on RCG) used some d-sub connectors from Radio Shack to connect all the wing wiring together, which I thought was an excellent idea, so I did the same thing. After getting all of the motors assembled and the wiring completed, I mounted the aileron servos and glued the motors to the wing. I used clear packing tape to cover the channels that contained the wiring.

03-09-2006, 03:56 AM
After completing the wing, I then moved on to the fuselage. I started by mounting the rudder and elevator servos forward of the central bulkhead. I then ran the pushrod tubing to the appropriate locations. This is the same as was done in the E-Zone review of this kit. This would help with my CG without having to add dead weight to the nose. I also expanded my battery tray to accept my 3S 1000mAh Lipo pack, but I left it tight enough so that it would not shift in flight. I made it so that the majority of the pack would also sit forward of the CG.

I then hooked up my Rx and ESC, turned on my radio, plugged in a battery and centered my servos. This was critical as once I closed the fuse, I would not be able to have access to my rudder/elevator servos unless I cut into the fuse. In the end, I may wind up creating an access hatch anyway, but only time will tell.

Satisfied with the servos, I glued in the assembled nose gear and joined the fuse halves together. I also mounted the tail surfaces and connected the pushrods.

03-09-2006, 03:58 AM
The last thing I have done was assembled the main landing gear, and then buttoned everything up to see how she looked. I tried to run up the motors with the props attached, but they will need to be CA'd on as the set screws do not work. Or, I may try to rig up a mounting system as described in another build thread.

Next step will be to assemble the trapeze and wire system, carve out the bubbles for the rear fuse section and the external wing fuel tanks, and paint. I only get about an hour or so each evening during the week to work on this, so it's been slow going. But now that the majority of the assembly is complete, I can concentrate on the finishing touches. Will update with more progress in a few days.

03-09-2006, 03:59 AM
OK, so I am almost done with the build. Just a little more paint and some decals, and I'm in business!

So picking up from where I last left off, I decided that I needed access to the servos that I mounted forward in the fuse. I cut out a hatch area in the belly of the fuse. It's kinda hard to mess with the servos, but at least I can get to them if necessary. To secure the hatch, I pirated some pieces from my E-flite Cessna 182 (Rest in Pieces http://static.rcgroups.com/forums/images/smilies/frown.gif , http://www.rcgroups.com/forums/images/smilies/smiley35.gifing glitches!). Same principle in that the balsa protruding from the hatch cover holds it in place in front, while the magnets are located in the balsa pieces in the back. A small tab protrudes from the back portion to grip it for removal.

03-09-2006, 04:02 AM
Next, it was time to add the mods that are not normally included in this kit. First, I created the protrusions that stick out from the rear fuse area, and I created the wing fuel tanks. These were all created from scrap styro. It was just a matter of cutting out the basic size, then sanding to shape. Toothpicks and 5-minute epoxy was used to attach them.

Then, I created the trapeze assemblies for under the tail fins. The forward part was made from flat carbon fiber stick, the rear portion from CF rod. I also used the flat CF for the outer connection points for the rigging on the vertical and horizontal stabs. Then, I ran a single piece of braided fishing line around the outer perimeter for the basic outline of the rigging in a diamond shape. I cut individual strands of thread, poked holes in the top of the horizontal stab at 1/2" intervals, and afixed the threads with epoxy and CA. I then mixed another batch of epoxy, let it start to set up, then fixed the threads to the upper rigging. After the epoxy set, I trimmed off the excess braid with an xacto knife.

03-09-2006, 04:04 AM
Now that assmebly was complete, it was time to paint. I mixed up the lighter color for the two-tone paint job, hooked up the airbrush, and could not get it to function. http://static.rcgroups.com/forums/images/smilies/mad.gif Not sure what the problem was, but I worked at it for over 30 minutes. Frustrated, I decided to brush on the paint. Turns out I did not mix in enough white with the gray, and it turned out darker than I initially wanted (see the first pic in this thread). Oh well, I then decided to go with the current paint scheme which is one solid darker gray color. Then, I ran out of paint. http://www.rcgroups.com/forums/images/smilies/smiley35.gif Had to go back to the LHS today for more.

So painting will get completed tomorrow, then decals will be applied later this week, with maiden to occur this weekend.

I weighed the plane before applying paint, and with all mods and a 3S 1000mAh Lipo, it comes in at 503g. I will weigh again after paint. I also did some taxi runs in my street, and man those 4 motors sound sweet when they are all humming along together. Got her to just below take-off speed and killed the engines. With the 3S, I definitely will not be flying at any more than 1/2 throttle. I will put the meter on later to see what I'm drawing at WOT.

More in a few days when complete.

LOL, almost forgot to show a picture of the prop paint scheme. I used Testors Steel for the color.

03-09-2006, 04:05 AM
Finally, I am finished with my build! And although I'm not exactly thrilled with the final paint scheme, I think it still came out OK. The final touches consisted of finishing the paint job, painting the wires in steel, and adding the decals. I used some of the decals from the kit, but I also had to custom make some others. I downloaded the font for the letters and numbers, and copied some Air Force logos (USAF Europe and Electronic Security Command).

Final weight, 518g, 18.7oz. Paint added 42g, but I saved 27g by going with a TP1320 2S instead of the 3S. I may have a CG problem because of all the stuff on the tail. I think CG is at around 55mm from LE. I have read that most planes fly better with CG around 50mm. A few grams of clay in the forward fuse may be in order.

I plan on maiden this Saturday if the weather cooperates. It seems we may finally get some of the rain that we so desperately need here. But of course it wants to come on the weekend I want to maiden a new plane! If I do get it flying this weekend, I hope to have a fellow flyer get some video, which I will post here.

Sorry about the low light in the pics. It's dark right now and I don't have the best lighting in my house. I will take a few good daylight shots before maiden and post them also.


03-09-2006, 04:08 AM
So there you have it, three weeks worth of building all in one shot! I should also mention that I decided to go with 2S lipos instead of 3S. And it just so happens I got my 2 TP1320 2S packs in the mail today from www.rctoys.com (http://www.rctoys.com).

Maiden to follow.

Happy flying!


03-09-2006, 07:55 PM
Just took a few more pics, this time in bright sunlight. Enjoy!

Sky Sharkster
03-10-2006, 12:04 AM
Hi Pat, great build thread! Thanks for all the info and photos. You should be making the GWS instructions for the kits! Let us know how it flies. It has to be the most realistic C-130 I've seen.

03-10-2006, 03:05 AM
Hi Ron, thanks for the kind words. Don't worry, there will be plenty of flying pics and video of the maiden. We have a large group of flyers (Turbo Joe and zzonie77 fly with me) and there will probably be a few video cameras running.


03-13-2006, 10:09 PM
Bad weather in Arizona this weekend, so no maiden yet. Maybe next weekend. In the meantime, here's a few more pics.


03-20-2006, 05:21 AM
Got a short maiden in yesterday. Winds were up and down due to a front approaching, so I took advantage of a brief lull and got about 4 minutes flight time. Long enough to trim it out and fly some ovals. Even got a nice loop out of it.

Hopefully the weather will be more cooperative next weekend and I can get more time on it, along with some good video. Yesterday's did not turn out very well.


05-23-2006, 04:17 AM
So I've decided to do an upgrade to the power system. I am removing the stock EDP-50 motors and replacing them with sp180's. In order to accomplish this, and to keep a scale appearance, I had to buy some additional equipment. Here is a list of parts I bought for this conversion:

4x E-flite sp180 brushed motors, part #EFLH1211
4x GWS Prop Adapters, part #GWSDS001
4x GWS 4025 props
GWS Direct Drive power system, part #300HC
Rubber tubing

The GWS Direct Drive power system was purchased as it came with 6 spinners that were just the right size to fit the new props (the sp300 motor and 6" props will go into the spare parts bin). The props are exactly the same as the stock props from the kit, except they are 4" vs 3". The rubber tubing I had in my stockpile of stuff, and I don't remember the inner diameter of it. But, it was perfect for this application.

The first step was to add a small length of rubber tubing to the threaded prop shaft. This is because the inner diameter of the prop hub is larger than the shaft. I cut a piece the length of the prop hub, and slid it onto the shaft.

Next, I slid the prop on and secured it with the washer and nut supplied with the prop adapter.

Then I added the spinner. The only problem here is that the spinner is designed to fit a much smaller prop shaft. I wound up cutting out most of the mounting rubber inside the spinner, leaving only enough to squeeze it onto the shaft securely. As it is now, the spinner does not snug all the way down to the prop. I may wind up taking the dremel and sawing off about a 1/4" of the shaft for a snug fit.

I have started fitting one of the motors into an outboard nacelle. Once I get one mounted properly, I will post the procedure here.

05-23-2006, 04:19 AM
This series will show the final steps for the conversion.

First, I decided it would be easier to just de-solder the wires from the current motors, then resolder onto the new ones, instead of trying to remove the wiring itself. The first pic shows the original motor mounted to the nacelle. After removing that, and the two mounting sticks, I pressed the new motor into the styro a little to make an outline. Then, I used an xacto to cut around the outline. Next I grabbed the neddle nose pliers and just dug out the styro deep enough to accept the new motor. After test fitting to ensure the correct depth, I then soldered the wires to the new motor.

Next, I cut out new holes for the stick mounts and glued them in. The new motor has flat sides on opposite ends, and the sticks rest up against the flat sides. At first, I was just going to secure the new motors the same way as the old, by wrapping a rubber band around the motor and stick mounts. But I realized that the motors would shift inside the cowlings under sufficient thrust. Therefore, I devised a retaining system by using some left over piano wire from my Tiger Moth kit. I bent the wire into a "U" shape, with little hooks at the top of the "U". I then poked holes in the stick mounts for the wire hooks, installed the wire, and wrapped with a rubber band. This should prevent any motor movement during flight.

Finally, I installed the prop adapters, put on the cowlings, and mounted the props and spinners. I still have one side to finish, then paint the props as I had done the old ones. I'll post some final pics when completed.

05-23-2006, 06:50 AM
Great job Pat! I intend to build one too next month. I already got a hard copy of your posts and this will definitely help me with the build. Anything else to watch for please post it. Looking forward to hearing how it goes after a good flight.

05-23-2006, 02:21 PM
Nice Pat!!! I bet it will really get up and go with those new motors. Nice job on the upgrade. I like your ideas on the connecting the props... Am still looking at options for mine.

Will be waiting for the flight report now.:D

05-23-2006, 04:50 PM
Thanks for the comments guys. I'm really looking forward to more power (argh, argh, argh) :D

Will be waiting for the flight report now.:DHopefully by the end of this weekend, I'll have a report AND video to boot.

05-23-2006, 05:03 PM
Hopefully by the end of this weekend, I'll have a report AND video to boot.


02-01-2008, 12:47 PM
What ever happened to that video?

02-01-2008, 09:34 PM
Never did get any video of it after the upgrade. Most of the guys I fly with are afraid of video cameras. :p

I now have a Quad EDF version that I will be building soon. I'll definitely get video of that.

02-02-2008, 03:14 AM
build thread!!!

02-02-2008, 03:16 AM
Jawohl, mein Herr! :D