Compy 3m Yak 55 Assembly


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OK... lets get this thing started!!

Last nite, I cleaned up the work benches, and photo'd all the stuff for CaliNative's Compy Yak I am assembling.....

He is using a bunch of smart fly stuff.... (All new to me.. so if you have experiance with this stuff... help me out!! lol) and Fromeco batts and a DA170 with KS95's.....

Lets show some Pix.....







the bottom of the yak fuse is very round... I may need to use a wire tail wheel instead of the carbon leaf spring....hmmmm??


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He did get pretty much everything 'cept wheel collars and servo extensions....

spinner looks beautiful!








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I really like this plane... and I like the scheme... ('cept the big black "JR" on the wing ;) lol )








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I have had like 3 Compy Super Extras... but I think I like the layout of this fuselage better.... there is a seperate Cannister section.... essentially.. the exhaust isn't inside the plane with the fuel tanks, batteries and radio equipment....





Tired Old Man

Staff member
I like that tailwheel. I have a 2.6 Yak and the one thing on the entire plane that troubles me most is rudder tiller linkage attachment points from the rudder. Hopefully there was a little more consideration for this item with the 3m plane. Attaching cables to the rudder horns imposes quite a bit of a down load on the phenolic horns, which will likely cause them to give up far sooner than they would normally. There's no place on the bottom of the rudder to attach a secondary tiller, and the rudder itself is hollow so it would not easily accept drilling of a hole in the bottom for a rod direct to the tailwheel.

The only thing I've come up with is the addition of a couple of brass swaging sleeves over the pull-pull wires before they are swaged for the pull-pull end connections. The spare swage tubes would be used for attaching steering cables to the rudder pull-pull cables forward of the rudder horns.


You understand carbon about as well as the best of the best so here's something I did with my gear legs for attaching the spats. The spats on the smaller plane are attached using a couple of sheet metal screws drilled and tapped into the end of the round carbon gear leg. I didn't feel that there was enough leg "volume" where the screws had to be drilled to permit them to have any strength and survive for any length of time. I roughed up and cleaned the ends of the gear legs and added enough carbon mat material to oblong the end of the gear leg ends fore and aft a little for more supporting area for the attaching screws.
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Well-Known Member
Yeah yeah... That's right JR.

I had Futaba back in the day. I traded in my Futaba Attack-4 for a JR 8103. LOL. I'm using the JR 9303 2.4 and have no complaints. I usually fly at "the Basin" in Van Nuys a place that is "Notorious" for radio hits and my JR's have never given me a problem. Not to say Futaba is crap, they make great products. I guess it was just "that day" i decided to buy a computer radio and JR was the result.

I like the JR scheme by Comp-Arf but everybody seems to have the yellow/black version so i swapped the colors.

You should have 2 white rose tail wheel assy's Mith (1 leaf spring, 1 wire) other than that i think that's pretty much everything i bought.


Lifetime Supporter
This is awesome, I have always loved the Copy Yak. I never understood why there weren't more out there. I look forward to watching this one. Mike, you'll get over the aversion to the JR stuff. Getting a little red under those orange & black fingernails will do you good... LOL.
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Well-Known Member
The wings...

I like the one wire connection per wing as opposed to two. It's a setup i've used for years and it has worked for me.


Circus Staff
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OK... so tonight I got some actual work done!

Fortunately, Comp-Arf starts out with the Landing gear installation.... I usually do this anyway as it gets the fuse off the table... less prone to scratches I think....

The main gear struts pretty much just slide into the tubes installed in the fuse... and then a couple 6mm bolts to hold'em in place.... I like to put a bit of silicone on the fasteners as it seems to hold'em in pretty well... but it is still removeable....




The supplied wheels are kinda Bling-Bling.... they use 6 4-40 fasteners to clamp the two rim halves t'gether.... here I put a little silicone on the fasteners too....





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here you can see the tightend Strut fasteners located inside the fuselage.... very easy to install this LG system!!


so now I assemble the axles.... the hubs are thinner then wheels like Dubros... so I had to shim a lot with washers...

The root end of the axle does clamp the wheel fairing to the strut end, so I used a fender washer here to get good clamping on the hardpoint in the fairing.....



I am going to bond the fairing to the strut with more silicone.. so I sanded the mating surfaces so I will get a good bond.... again.. the silicone seems to be a pretty robust bond yet can be seperated if needed... a bit flexible too... better for wheel fairings that get shock!



On Gear.... I do need to remove the axles after the silicone cures to add the two small screws that secure the fairing to the strut.



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here is the new White Rose Tail Wheel Assy I will use that has a 1/4 inch wire instead of a carbon leaf-spring... fits on rounded lower fuselage better!!


And now I install the nose bowl.... the joggle was a little deeper then the thickness of the nose bowl, so I shimmed it with a few layers of tape.... marked the nosebowl 7 mm from the aft edge, taped it all in place and drilled the 3 mm screw holes..... tomorrow I will wax the screws and then bond in place the "T-Nuts"....





Looks pretty good huh??

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