Rescue Tandem with CH47 Chinook Fuselage - RC Groups
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Dec 27, 2013, 08:56 PM
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Rescue Tandem with CH47 Chinook Fuselage

This blog post describes how I fit a CH47 Chinook fuselage from a Nine Eagles Twingoo coaxial tandem helicopter onto the mechanics for an E-Flite Tandem Rescue.


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Last edited by RoboHeli; Dec 27, 2013 at 10:20 PM.
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Dec 27, 2013, 09:09 PM
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One of the things that I've been meaning to do for about a year now is to mount a Nine Eagles Twingo fuselage on the mechanics of an EFlite Rescue Tandem. The Nine Eagles Twingo is a great example of a CH-47 Chinook while the E-Flite Tandem Rescue is a CH-46 Seaknight. The Twingo comes in two different colored fuselages. The first is a "civilian" yellow and the second is a military camo pattern.

My primary problem with the Nine Eagles Twingo is mainly that I can't stand the little game-pad controller that comes with it. Compared to all of my other helicopters (both RTF and those I fly with my programmable TX), I'm ALWAYS chasing the throttle on this heli and it's just not as fun to fly. My secondary problem with this heli is that the battery is the proprietary Nine Eagles type which is incompatible with any sort of plug that I can connect to my nice computerized charger.

However, thanks to the magic of EBay and Amazon (primarily the vendor hopmeup), EFlite Rescue parts are still plentiful! I cobbled together what I needed to assemble the mechanics of two EFlite Rescue Tandems and i was ready to start modding.

Step 1: Repositioning the landing wheels.

The Seaknight has a single landing gear wheel right under its nose but the Chinook has a pair of wheels mounted further back. First, I removed the front landing gear from the EFlite mainframe. Then I bought a second set of the rear landing gear for the EFlite Rescue and was able to install it in the cross brace that is part of the internal structure here.

Then I had to move the EFlite rear landing gear back as far as I could. This was easily done by removing the screws that hold the landing gear mount to the frame and sliding the entire assembly as far back to the rear as you can. I didn't even bother to secure this piece though you could certainly do so with a little bit of white glue or something.

Finally, because the landing gear hubs are yellow plastic, I used a Sharpie paint pen (not the basic Sharpie marker) which is an oil-based paint to color the hubs black as best as I could.

Step 2 : Attaching the fuselage to the frame

The Twingo fuselage is a very good fit for the Rescue Tandem frame. The proportions are right and the canopy mount pins for the Rescue Tandem line up very well with places in the frame where you can drill a few holes for mounting them. The only problem is that the canopy mounting pins are not long enough to go through the Twingo fuselage.

To fix that, I got some of the canopy extender pins from the MCX S300 canopy (part number EFLH 2327) and put them on the Rescue Tandem canopy pins. I had to secure the rear ones with a little white glue (heat shrink tubing might also work) but the front ones were pretty tight. In fact they were so tight, I cracked one of the S300 canopy pins and had to glue it anyway.

Here's what the front canopy pins look like:

and here's what the rear canopy pins look like:

Finally, I inserted the frame into the fuselage and gently positioned it where I wanted it to go, marked the locations on the fuselage where I needed to drill the new holes, and used a 5/64th drill bit to make the right sized hole. I used a pin vice and my fingers to make the hole. No power tools needed here!!!

Here's the front side where I made the hole for the canopy pin:

and the rear:

Step 3 : Finishing touches

Here's what the model currently looks like:

Things that I'm still missing are:
  • Coloring the white MCX S300 canopy extenders black. The white pins stand out like a sore thumb and I think black ones would look better.
  • Removing the Nine Eagles LEDs and installing the EFlite LEDs. The pins on the Nine Eagles LEDs are square and don't fit into the round holes of the EFlite receiver board.

when I take care of these, I'll update this blog post.

Step 4 : Go Fly!!!

I'm still experimenting with the CoG on this model, but so far it flies really well. I think it tends to be a tad tail-heavy so I might try to add some weight in the front to balance things out. Otherwise I'm pretty pleased with the results.

Here's a picture of some of my Tandem helicopter models. The bottom three are all EFlite Rescue Tandems. I mounted the yellow Nine Eagles Twingo canopy on the mechanics of another Rescue Tandem.

Last edited by RoboHeli; Dec 27, 2013 at 09:16 PM.
Dec 28, 2013, 05:16 AM
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djdavies83's Avatar
Real nice job there man!
Dec 28, 2013, 04:41 PM
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Thanks! I really enjoyed putting this together. It's even nicer because I could do it all with stock parts from the different helicopters. There's no additional need to fabricate anything.

Too bad it's so hard to get the Nine Eagles Twingo canopies now. They're still out there but you really have to look hard to find them.
Jan 13, 2014, 12:13 AM
valiantGLX's Avatar
Excellent work Robo. Could you move the receiver/battery a bit further back instead of adding weight to get the CG right? I swapped out the plug on mine so I could use nanotech 300mah with jst-ph 2-pin plugs. After doing that I needed to move the receiver slightly forwards for a good CG
Jan 13, 2014, 09:25 AM
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Thanks! Yes, I agree that it's always better to move existing parts around rather than adding weight if you can help it. I'll try that first before adding weight.

I'm also using used motors from the models I bought off of ebay. I wonder if I'd get better results with new motors. I found some killer deals on spare rescue tandem parts this xmas but I haven't tried installing them yet.
Jan 22, 2014, 04:08 AM
Registered User

Help with the schematic.

Roboheli - very nice fleet of tandems. I have the Blade tandem and tried to replace the fuselage, but I forgot to mark the adapters from
The 4 servo and the 5 in 1 board. So now I don't know what goes where. Do u have a schematic or could u even just tell me where each go? Would really appreciate yours or anyone help on this.

Jan 22, 2014, 08:28 PM
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Here you go! And by 4 servos, you actually mean 4 brushed motors. There's only one servo on the heli and that's the little white actuator on the 5-in-1 itself.

Some quick photos snapped from my phone. They're not great but they should get you going again.

First, on the servo side of the 5-in-1 (the side facing the FRONT of the heli):

You'll see that the red/blue motor wires plug into the slot that's closest to the top of the top of the board and the red wire faces the white servo. The black/white motor wires are under it and the white wire faces the servo.

Now, on the back of the 5-in-1 which faces the rear of the heli:

You'll see that the red/blue motor wires are once again on the top of the 5-in-1 and that the red wire faces AWAY from the battery port. The white/black motor wires are under it and the white wire faces AWAY from the battery port.
Last edited by RoboHeli; Jan 22, 2014 at 08:34 PM. Reason: Uploaded better picture for the front image.
Jan 22, 2014, 08:36 PM
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I just uploaded a better picture of the front of the servo. The first picture I had was too blurry for my liking.

Also, if you go back to my original post, you'll see this picture of the green/brown tandem that also shows the wires if you look carefully (and read my description above!)

Here's the photo I'm referring to again.
Jan 22, 2014, 08:37 PM
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Hope that helps, Macymastiff!
Apr 10, 2014, 11:46 PM
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Nice collection of tandems! Would you be so kind to measure the distance between the two rotor shafts. I would like to convert a hcp100 to a chinook and was looking for the right canopy size that I can use.
Apr 11, 2014, 06:41 PM
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Originally Posted by aED__
Nice collection of tandems! Would you be so kind to measure the distance between the two rotor shafts. I would like to convert a hcp100 to a chinook and was looking for the right canopy size that I can use.
Hi aED__! I'd be happy to take a few measurements for you.

First, look at the Nine Eagles Twingo internals:

The distance between the center of the front & rear shafts is about 19.3cm. Thus either the Nine Eagles or the EFlite Rescue Tandem fuselage will work for you here.

If you want something a little bigger, please consider the dimensions of the Esky Tandem:

This is more like 21.1cm from shaft to shaft.

Plus the Esky Tandem has four different fuselage styles to choose from:

And some of them are on deep discount right now! Check them out here:
Apr 12, 2014, 12:13 PM
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Thank you very much! Especially for the links I almost bought that canopy for $14 Now I can start with my conversion
Apr 12, 2014, 01:00 PM
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Very cool. I'd love to know how it progresses! Please post pictures when you have a chance.

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