Sopwith Camel - Free flight scale power model of the British WWI fighter. For .03 - .049 cu engines.
Quote: "Your FREE plan! A 28 inch span free-flight scale model using 0.5 to 0.8 cc engines. Sopwith Camel, by DM Collins.
THE CAMEL, in the eyes of the author, was quite the most fascinating aircraft flown in the First World War and by all accounts also the most effective in terms of enemy aircraft shot down. However it has some very obvious shortcomings, as a flying scale subject which should be borne in mind by the builder. The full size aircraft was tail heavy and the model will be also unless care is taken to keep the fuselage aft of the cockpit, and the tail assembly, as light as possible. Use the lightest balsa available and limit the number of coats of dcipe applied at the tail end. Some relief from the CG problem can be obtained by making a really robust cowling of glass fibre with about, 3/32 in wall thickness, or at least by covering a balsa cowling with a layer of glass fibre.
The other problem is the small tail moment available with the scale tail area. One solution is to have a pendulum operated elevator. Pendulum controls are often justifiably criticised on the grounds that acceleration of the whole model will make the control operate, but remember that the only significant change in forward speed occurs at the launch and in that case the slipstream quickly damps out any such oscillations. Some folk limit the movement of the control surface, but the designer prefers to limit the weight on the pendulum relative to the control surface area, and rely on aerodynamic damping. Do not increase the weight 'for good measure'.
The outline is to scale although the wing section is thickened to improve warp resistance and give more docile flight characteristics. Rigging wires are not needed for flight which speeds up assembly time after hard landings, especially with cold fingers in the winter! Of course they may be added by the meticulous using shirring elastic thread, but on small models this often looks overscale.
Engine installation is a bit of a problem due to the shallowness of the cowling. This does seem to rule out those trusty Mills .75s but the original flew well on a DC Dart .5 cc, and the DC Merlin would also be suitable. Small glow motors are out unless they can swing a 7 x 4 in prop at a reasonable speed. Incidentally the torque of a Dart on a 7 x 4 can be improved by making a con-rod .02 to .05 in longer between the centres of the big and little ends. This reduces the exhaust and transfer periods of the otherwise high speed timing. Fortunately Darts will start and run without any adjustment of the controls once they have been warmed up, so for this reason no external access to needle valve or compression screw is provided. If you must twiddle, you will have to make an extension handle for the compression screw, the gap between the prop and the top wing is too small unless you have unusually high aspect ratio fingers! Alternatively the motor can be inverted, with appropriate adjustment to the thrustline, and the compression screw extended backwards by soldering on a wire to come out of the cowling bottom vent area.
Construction is quick and simple for a scale model but the following points will help guide you on your way. Start the fuselage by cementing a piece of 1/16 in sheet on top of the engine bearers to give the correct spacing, then bind and cement on the pendulum assembly. The cabane and undercarriage wires are bound and cemented to their formers..."
Quote: "Only a small model, but a great flyer with only a little power needed to stay aloft. Glow plug engines are not really suitable for this type of model due to their high revving characteristics - a diesel will turn a larger prop at moderate speeds... "
Direct submission to Outerzone.
Update 30/07/2016: article pages, text & pics added, thanks to RFJ.
Update 06/09/2018: Replaced this plan with a clearer copy, thanks to DBHL, theshadow.
Scan from DBHL, cleanup by theshadow.
Direct submission to Outerzone.
Article pages, text & pics.
Previous scan version.
Did we get something wrong with this plan? That happens sometimes. Help us make a correction
* Credit field
The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.
This model plan (like all plans on Outerzone) is supposedly scaled correctly and supposedly will print out nicely at the right size. But that doesn't always happen. If you are about to start building a model plane using this free plan, you are strongly advised to check the scaling very, very carefully before cutting any balsa wood.
© Outerzone, 2011-2018.
All content is free to download for personal use.
For non-personal use and/or publication: plans, photos, excerpts, links etc may be used, provided that full and clear credit is given to Outerzone with appropriate and specific direction to the original content i.e. a direct hyperlink back to the Outerzone source page.
Unauthorized use and/or duplication of this material without express and written permission from this site's owner is strictly prohibited. If we discover that content is being stolen, we will consider filing a formal DMCA notice.