The Ohmen

Of course that should read PDF files

Very surprised to see a thread on this started so early since it has only just been published in the mag.

I have an unusually empty building board at the moment so I was looking around for something to keep me occupied for a while.

I once built Peter`s Cap 21 which was excellent so I thought about scaling this back up for an OS52S, but not wanting a protruding silencer I found that the exhaust systems I have for the motor would not allow this.

I have a TGY 3548 and an AXI 2820/14 doing nothing and fit the power requirements so saw sense and have almost decided to have a go at it `as is`.

Will keep you posted on the results of my effort.

After a recommendation to build this model on a thread I posted recently, I to am looking to build this model in the near future. I’ll be looking forward to seeing your build progress in tandem. This will be my first plan build balsa kit, as opposed to a balsa WOT4.

Hi Martin

The thread was started when I first cut balsa for my prototype. Always glad txo see others adding to tthe thread.

NOTE that the triangular stock in the corner betwen F-1 ans the sides is missing. I checked and I am guilty, I forgot to add it to my own original plan.

Well, been hard at it since my last post and here is the result so far.

I changed the wing assembly method a little just to suit me but the component parts and end results are similar. I added large holes in the rear formers since I shall be using pull- pull on the rudder, and substituted vertical 1/32 balsa for the ply doublers to save a little weight. Not clear to me how the u/c is held in place so may go a little more conventional here and maybe make up a steerable tailwheel.

Martin Re: Ohmen undercarriage.

I just had a look at my copy of the plan, and the u/c wires are a fairly straightforward job. They're held/screwed to the underside of the fuselage with those little grooved nylon things ( can't remember what they're called ) and the vertical ends of the u/c wires - which go up into the fuselage, against the fus side ply doublers - are trapped in the two grooved ply blocks glued to the fus sides. It's just here you could have done with that ply doubler!  You can of course retro fit some in the areas where the u/c wires will be.

P.S. The nylon things I referred to earlier are saddle clamps......

Edited By Percy Verance on 23/09/2018 16:52:33

The plan shows a 1/8 ply plate across the fuselage and appears to show it covered with 3/32 balsa like the underside . 6mm birch ply would seem a good idea instead - something to get the saddle clamp screws to bite into.

The point about using 1/32 ply doublers is that in a severe crash the ply usually remains intact while the balsa splinters. The ply keeps the model straight enough to rebuild! And as Percy said it's really needed in the u/c mount area. For my model i would choose to use just a 2 inch wide strip of ply instead of the 3.5 inch height shown. Maybe with a triangle to extend up to top of F1 and a couple of filler strips at F2 and F3 to keep the surface level where it meets those formers. Save a lot of weight and expensive ply!

Yesw, there should be triangualr stock in teh F-1/ fuselage side joint.

The 1/32 ply doublers are very important they hold the sides tin one piece.

The 1/8 ply plate under thefuselage for the U/C mount is fine, Due to the long legs going up into the 1/4 ply slotted members it won't pull out.

I got disoritened and the model came down vericlly. I pulled it our and it smashed into the ground dead flat. The U/C just splayed out flat and the model bounced and flew into the field. The fuselage had a clean break just at the rear of the trailing edge. The U/C just needed bending straight (10 SWG insread of my usual 8SWG

Thanks for the comments. If I build the u/c as per plan then I shall obviously use ply between F2 and F3. I just asked the question because the plan does not appear to show saddle clamps so I wondered if it simply plugged in. Anyway, I do not try to make my models crash proof as I have no intention of bending them if possible!

Update soon.

The undercarriage does sort of plug in Martin, and the saddle clamps ensure it stays in.