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Old 05-28-2012, 12:14 PM
Leif Ohlsson's Avatar
Leif Ohlsson Leif Ohlsson is offline
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Clerget 9-cyl 130 hp 1/16 scale model

The testbuild of the enlarged Sopwith Triplane by Boats, "Sopwith Triplane 1/24 scale" triggered an urge to do some more work on this model. (The existing versions are here: "Sopwith Triplane N5486, 1/32 scale", and "Sopwith Triplane N5912, 1/32 scale".)

For one thing, the propeller needs improving. But that's already been done, as I found when I re-opened an old work-in-progress-file of the Triplane. In there, of all places, I found all the dozens of iterations of the "Simplified laminated propeller", now available as a download.

Next thing on the agenda has to be the engine, which - as Boats already has remarked - is just an outline of an engine.

So, I buckled down, got hold of an excellent drawing of the Clerget 9-cyl 130hp rotary engine by Mark Miller; and wrote to Richard Schulten for permission to use his design of the earlier 7cyl 80 hp Clerget as a base for making a proper 9-cyl 130 hp version.

Here's what the work so far looks like (one page of two or three):



You will not be able to read much from that illustration. So, please, download a high-resolution pdf-file of this testpage instead.

My question now to all interested is rather basic: Do you understand what this page says on how to build the 1/16 scale version of the Clerget rotary?

The thing is that this is an attempt to really recreate a properly working papermodel of a rotary engine. This is the way it (hopefully) works:

Quote:
The whole engine rotates, hinged as the fullsize in a unit which is fixed mainly to the firewall, and stabilized further aft along the long carburettor intake tube, and the two transverse air intakes at the rear. These will have to be dimensioned according to the aircraft you are building. (They are the little stubs sticking out from each side of most rotary engine WWI-aircraft.)

There is a stopper hidden inside the rear carburettor distance tube, which will prevent the engine from dropping off the aircraft. This means that you will have to build the rear section, and attach the engine to it, in a specific order:

1) Glue the rotary front, main, part of the engine to the 2mm shaft. Be careful to follow dimensions given in the sideview drawing.

2) Make the three bearings of 3 mm diameter (2 mm inner diameter) tubing.

a) Insert & glue the first piece in the main engine mount (the one that will be stuck into the firewall eventually).
b) Stick the rotary, main, section of the engine, on its shaft, through this main engine mount, and add the stopper piece of 3 mm tube. Glue this to the shaft. It will rotate, hidden in the carb distance tube.
c) Stick the carb distance tube onto the main engine mount, over the shaft, and its stopper. Glue it at the front end.
d) Stick the last piece of the bearing into the endpiece, and insert this into the rear end of the carb distance tube, over the shaft, joining the carb distance tube, and glue it to that tube. The shaft & stopper will now rotate freely inside (since the distance tube is of slightly larger diameter), supported by the bearings in the main engine mount in the firewall, and the bearing in this end piece (which usually ends up almost in the pilot's lap).

3) Mount the prop (the simplified layered prop will be included in the engine kit).

4) The engine is now finished. It is entirely self-contained and can be plugged into the large, true-to-scale, diameter opening in the firewall.
I guess I ought to add some text like the above in some free space on another page.

Another feature is that the engine model is consistently built up of cylinders and cones made by parts which have gluestrips almost as large as the outer part, plus lids top & bottom. The technique has previously been described here: "Making paper cylinders with a ledge & full inner layer".

Any particular question marks? Immediate suggestions for improvements (clarity, readability, etc.)?

I realize that I may have gone over the top with arrows and explanatory text pieces. But on the other hand this engine drawing is consistent with the rest of the Triplane kit, and the propeller kit, in that it has no part numbers at all - everything is explained in words and arrows.

I plan to include photos of the build, of course (when I get to that); there already is 3/4 of another page with cylinder parts, and some white space left for these photos.

Still, though, what are your thoughts?

Leif

Last edited by Leif Ohlsson; 05-28-2012 at 12:42 PM.
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