Cumulus (oz5363)

About this Plan

Cumulus. Free flight gas model. Classic design.

This full-size plan seems to be a faithfully drafted enlargement of the original Cumulus drawings that were printed in Flying Aces 1937. This is good because the original drawings (see supplement file) needed a lot of scaling up and did not show details like individual wing ribs. Plan says 'Drawn by Ben Shereshaw' but that might mean model design rather than actual drafting(?).

Quote: "Construct the 'Cumulus', by Ben Shereshaw. There's no thrill to compare with the joy of handling a real airplane in flight.! But perhaps the nearest approach is to launch a sky-scooting gas job into the air. And great indeed is the enjoyment if the gas fan has made his plane himself. You are assured of satisfaction and success in gas model flying, if you'll build this new ship of Shereshaw's - the 'Cumulus' - for she's inherently stable. And what's more - she's easy to build!

IN designing this Cumulus model for Flying Aces gas model fans, I have tried to combine scale appearance with con-test performance. In other words, the Cumulus - named after the massed cloud formation - is a ship that not only looks good, but also has what it takes when it comes to satisfactory performance.

Because of her high thrust line, she is an extremely stable flyer and you can depend upon her every time - if you carefully follow my instructions for building her. She has a good glide ratio - around fifteen-to-one with power off.

In preparing these instructions, I have assumed that the out-and-out amateur would not yet be ready to build this gas model. So while the Cumulus is really an easy ship for the chap who has had a little model making experience (Herb Denaci, who built the original model from my plans, is sixteen years old), I have glossed over the details that such a model hobbyist would normally know and have stuck entirely to the straight, practical end of the construction.

If, however, any reader should run into difficulties in connection with this model, he has only to drop me a note with a self-addressed, stamped return envelope and I'll do my best to straighten him out.

Fuselage. The first step in building the fuselage is to lay out the side elevation. This is done by scaling the side view up to full size, with an architect's or mechanical engineer's scale. The longerons are made of 1/4 by 1/4 hard balsa, and are selected for their uniform texture and even bending characteristics - since longerons having variable bending qualities are apt to distort the fuselage.

The fuselage sides should be assembled on a piece of plywood or similar material, which must be absolutely level. Cut the compression members to size, and insert them at the proper stations as indicated on the plates. Then, cut your diagonal braces, and be sure to cut them so that part of the diagonal rests against both the longerons and the compression members. You will note that the diagonal bracing at the nose is of 1/4 by 1/4 balsa, and the diagonal brac-ing backward from the wing is of 1/8 by 1/4 balsa.

See that each member makes a snug fit, and do not try to correct a poor fit by filling the crevice with cement. Use the very best cement available, and proceed by cementing all the compression and diagonal members securely in place.

The next step is the assembly of the fuselage. Our top longeron being straight and the lower one curved, it is easier to assemble the fuselage inverted. Start by cutting the cross-members, then cementing the center portion of the fuselage together. Be sure to cement both the top and lower members to the fuselage sides at the same time, Following this procedure, work back until you have reached the stern post..."

Direct submission to Outerzone.

Added article, thanks to Orange&White.

Supplementary file notes

Article. Includes original drawings, as published 1937.

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