Scale RCM 1/3 Scale Champ Build

[TonyHallo]

When I purchased the engine some time ago there was some discussion about hesitation with the 4 strokes and the need of an electric fuel pump. Everything works as intended on the Roto from I can tell so far. The fuel tank is about 4" below the carb, after choking and flipping I pulled the fuel line at the carb and found gas. Once started the engine loosen up quite a bit although I had to put a few drops of gas into each cylinder to get it run at first. I did 3 temperature cycles yesterday allowing the engine to cool down to ambient temperature. On the third start, one choke flip and one flip and away it went.

 

[Snoopy1]

I do like it, I'm thinking I might just finish off that Super Cub with one. The plane was built using a 3W 56 CS engine, never ran, just might sell it and buy another Roto 85. Need to check the cowl size, the 3W fit in just fine.
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Back to work on the Champ, enough of this playing around with engines. I built a box out of scrap 3/8" plywood to support the form for the windshield plug. I treated the mold with Pam cooking spray for release then filled with Plaster of Paris, man does that stuff setup quick! From what I read on the web they suggested filling the mold 1/4 at a time so that's what I attempted, messy stuff for sure, I made a foam filler to minimize the amount of plaster needed, this was just short of a 25# sack.
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Tony please give me chance to buy the 3w twin if you decide to sell. The exhaust looks different?

 

[TonyHallo]

I cut the tubes off and made a single scale like exhaust. I believe the mufflers were Johnson brand? Pretty sure they came from AI.

 

[TonyHallo]

I did find that Johnson mufflers were sold by AI, they have 1 muffler listed. On another search I found that they are out of business and this guys mufflers for the 56 twin were leaking. It has been a while since I looked at them but from what I remember the mufflers were nice, they are little more than typical manifolds you find on engines today, might actually reduce some noise.

 

[Snoopy1]

Interesting setup you went through a lot of work to make it scale. Looks good.

 

[TonyHallo]

Looks like the 85 will fit inside the cowl, once the Champ is finished up I'll study the Super Cub and determine what I'm doing, petty sure I will parting with the 3w 56 CS.

 

[TonyHallo]

Control sticks, I purchased the white stick in the photo below from I Fly Tallies, it is a little short for the Champ and I thought it shoud be a little larger in diameter based on the photo below. For reference the same gauges are 20mm 1/3 scale so I estimated the control stick diameter to be about 10 mm or 3/8". A Google search found that Advance Auto has 3/8" aluminum tube in 1' lengths, box of six for $1.59, hard to beat, this is used for repairing auto A/C tubing. It's called hard on the box but the tubing bender had no problem bending to shape. I have 1/2" aluminum balls on the way from McMaster Carr.

 

[TonyHallo]

Found the control stick cover for sale online, I made mine from the same material that I covered the dash with. Thought I could just use fabric glue to assemble but had to get out the needle and thread and put three stitches in the seam. I think I going leave the stick natural aluminum colored, I found a couple of used sticks for sale that were natural. Need to come with an attachment method yet, needs to be removable to service the wiring under the dash.

 

[TonyHallo]

True story,
Yesterday I ran the engine with the cowl on, ran it at less than 1/4 throttle until the temperature quit increasing. The cylinders were approximately 260-270 f, both temperatures on ignition module slowly increased to 132f at which point the engine began to miss. Shut it down and let it cool, started and ran the tank of fuel. I decided to move the ignition module inside the cabin area. This morning took everything apart and removed the dash and boot cowl, mounted the ignition on the cutout for the carb and thought I should check to see if everything is working, power on, the power indicator did not come on, check wiring and connection, back probe the connector plug on the module side, 8 volts, ignition dead. I had purchased the engine from a seller on Ebay, maybe ShoSho?, any rate can't find him now. Vogelsang now is listed as the US distributor, new ignition is listed at $175. Rather than mess around, called CH Ignition and mailed the engine off to Adrian today, it will cost a little more but no need to worry about the temperature limit and if fails again I can just swap out the ignition. It's hard to image they can't make an ignition module that isn't so sensitive to temperature. The RcExcel instructions have you mount the ignition on the engine box and caution you about mounting inside the fuselage! Just another set back!

 

[dhal22]

Better on the ground than in the air.