Magpie (oz15528)

About this Plan

Magpie. Radio control sport trainer model.

Quote: "Never built or flown an R/C model before? OK, start here with this 50 in span vintage-style cutie. John Rogerson spells out the procedure.

I originally designed the Magpie as a model that I could use for relaxed sports flying that would also double as a good trainer for two of my friends' young children. The 50 inch span, 12 inch chord wing allows the model to be flown very slowly and it can almost be hovered in a light breeze. The fully sprung undercarriage assembly takes most of the shock out of early landings and if you do not have the benefit of flying from a mown grass runway then the model can be easily hand launched.

You will need two or three channel radio control equipment and a model engine of .15 to .25 cu ins. You will also need to purchase a supply of balsa and plywood in various sizes and a suitable covering material in the colours of your choice. Litespan is highly recommended for this.

The model's construction follows the time honoured traditional aeromodelling technique and enables the builder to cut out and assemble the model in a very short space of time. If this is your first model aircraft then welcome to the fascinating world of powered flight. If, on the other hand, you have built and flown models before then you can probably skip the rest of this page and go straight on to the building instructions.

Before you start construction, read the instructions several times and make sure that you understand where everything is supposed to fit. Always check the fit of mating parts before applying glue as some minor adjustments to size are sometimes required in order to obtain a snug fit. The better the joints, the stronger the finished model will be. It is also important to build the model accurately over the plan so that all of the rigging angles are maintained. Now let's make a start!

Wings: Lay the wing plan flat on your building board and cover it with cling film to protect it. On a separate cutting board, cut out all wing parts that are prefixed with the letter W.

Build the right (starboard) wing first, directly over the plan as follows. Glue and pin down rear (trailing) edge parts W12, W11 and W10. Then add the wing tip W9 and front (leading) edge W8, gluing mating surfaces and pinning as before. Now add the main spar W5 by gluing it where it meets W9 and pushing pins on either side of the spar to hold it in an upright position. Add the strip of 1/4 x 5/8 leading edge by gluing to W8 and pinning down at intervals along the length. Do not worry about contouring the end of the leading edge where it joins W8 for the moment, this can be done when the wing is dry and lifted from the building board.

Pin down the lower, rear 1/8 square spar, remembering to glue where It joins W10. Now check the fit of each of the ribs W4, W3 and the two W2s and then glue in place. W1, which is 1/8 balsa, should be slightly shorter than W2 to allow the 1/16 ply front and rear dihedral braces to fit. The slot that takes the mainspar should also be 1/16 wider to allow the centre ply dihedral brace W14 to fit. Glue the 1/16 ply brace W14 to the spar (W5) , holding it in place with clothes pegs. Add the root rib W1 followed by front and rear braces W13 and W15. Note that this rib lies at an angle against the mainspar W5.

Last of all, add the two front 1/8 square turbulator spars in their notches, terminating at the rib W4. The rear 1/8 square spar can also be added which also terminates at the rib W4. Lastly, add the tip braces W6 and W7. When the wing is partly dry, cut a 1/8 wide and 1/8 deep notch immediately in front of the mainspar W5 and glue in a 1/8 square strip by applying glue to each rib and also to the front of the mainspar W5. Hold this spar in place with clothes pegs until dry. Leave the whole wing assembly overnight to dry.

To make the left (port) wing, place the wing panel you have just completed on the drawing so that the rib W1 butts up against the port wing outline that is shown extending from rib W4. Now raise just the tip of this wing so that it is 5 inches from the board. With the wing in this position the bottom of the ply dihedral braces should be flat against the plan.

Now construct the left (port) wing panel using exactly the same sequence the first, but this time using the port wing outline to locate the parts. Once again leave the assembly overnight to dry thoroughly before lifting from the board. You should now add the triangular reinforcement gussets to the rib trailing edges as shown on the plan.

You will now need to shape the wing leading and trailing edges as shown on the plan. This can be done by carefully shaving to size with a knife but a better alternative is to use a razor plane..."

Magpie from Radio Modeller, March 1996.

Direct submission to Outerzone.

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