Sopwith Pup (oz9660)

About this Plan

Sopwith Pup. Radio control scale model WWI biplane, for electric power with geared Speed 400 motor and 3 function radio.

Quote: "Hi Steve and Mary; I was looking at Mike Roach's Sopwith Triplane (oz9773) which references a Peter Rake Sopwith Pup as the basis for the triplane. A search for this plan brought it up on Aerofred. Attached is a copy of the file. Keep up the good work! I love seeing these old plans and look almost every day for what is new. Cheers, mjb"

Update 05/04/2021: Added article from Flying Scale Models, November/December 1999, thanks to RFJ.

Quote: "Peter Rake adds another electric powered R/C scale model of a WWI aircraft to his range, designed for three function control and geared 400 size motors

The SOPWITH PUP has always been a great favourite with modellers, largely because it doesn't seem to matter what scale it is modelled to - they always fly well. This particular Pup is no different! This series of models is designed, mostly, around the 2.33:1 geared Graupner Speed 400 unit. When powered by 7x500AR cells and turning a wooden propeller of about 11"x 7", a fine and mildly aerobatic performance is to be expected. Since all the models in this series are to a constant 1/9th scale, they compliment each other admirably. With flight times in the region of six minutes, a lot of fun is to be had with them for a minimal outlay.

Being small and quiet, you can fly your model from most smallish fields without upsetting anyone. I live about two minutes walk from our local cricket field, which means that I don't even need to take a charger with me when I pop out for a quick buzz around. It is very nice just to nip back home for a cup of tea while the model recharges. Anyway, enough on basics - I don't doubt that you'd like some more detailed information about what is involved in order to build the model. Here we go then.

EQUIPMENT: Since I like to build this type of model for rudder/elevator control, whenever practical, it keeps the number of servos required and therefore the weight, to a minimum. The model will need mini servos at the very least. Micro servos will save even more weight, but are not absolutely essential for success.

The one item that is mandatory in order to get the best from your model is a speed controller. This one item will do more for the versatility of your model than anything else I can think of. So, please don't be tempted to fit a simple on/off switch - the gears in your motor unit will appreciate it too, otherwise you run the risk of having teeth everywhere but where you need them - on the gears.

A standard size receiver is acceptable if you really don't have anything else, but will use up a lot of the weight you could otherwise have used to detail your model. Since there are now some excellent sub-micro units available at very reasonable cost (cheaper than many standard ones), it would be well worth investing in one. The actual equipment used in my model is comprised of a JETI 4 Rx, two HS50 servos and a KONTRONIC EASY 1000 speed controller, giving an all up weight of the flight pack of about 1.5 oz. This is less than some standard servos weigh.

Don't, under any circumstances, be tempted to use anything other than SANYO 500AR cells for your power pack. I have yet to find anything else that comes even close to them for lightness, performance and longevity. They really do work out cheaper in the long run.

Although I designed this model around the Graupner motor unit, other brands may be substituted. It may well be necessary to modify the motor plate or even the entire mounting system to suit them however.

CONSTRUCTION I have deliberately kept this as simple, and as light as possible. To this end, I have made the model a one-piece assembly. Should you wish to make your model disassemble-able it would prove a fairly simple task to replace the lower wing locating dowels with tubes and wire wing dowels and to have the top wing mounted with saddle clamps..."

Supplementary file notes

Article.

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