Rambler (oz12763)

About this Plan

Rambler. Free flight power model.

Note this is not a full size plan, this is a scan of the article and drawings as printed in the magazine pages, in 1939.

Quote: "Rambler, by Gilbert Shurman.

All petrol pretties are not the same - no, not by a long shot! And here's one that's so much different that she stands alone. In fact, she's one of those 'once in a life time' models that you'll want to build before finishing the one you're working on now! Because the 'Rambler' is not only different - but she's a contest winner, too! So if you want to bring home the bacon from tourneys, gather around and follow Gil's instructions.

HERE'S a gas model that will satisfy the beginner and expert alike with its ease of construction and flying ability. The Rambler was the result of several months of deep thought plus two weeks of drafting and building. It was designed expressly for limited engine run contests. And when finished and flown, it more than fulfilled all performance expectations.

The Rambler was completed during the early part of September, 193S, and was taken to the Second Annual Quaker City Gas Model Airplane Association contest at Northeast Airport, Philadelphia. But, due to the poor weather preceding the meet, the ship had to be tested on the morning of the event.

Although testing a gas model on the morning of a meet is hardly recommended, in this case ithwas followed with a first place. On a 19 second motor run the craft stayed aloft for over 22 minutes!

The next time the Rambler was flown was in March, 1939, at the Metropolitan Model Council Meet, at Creedmore, Long Island. Here it turned in an unofficial flight of 16 minutes on a 17 second motor run. This time it disappeared from sight and has not been heard of since. On normal fights (no risers) it has always shown a 4-to-1 ratio between the climb and glide, which, under the present 20 second ruling, allows 1-1/2 to 2 minute average flights.

In concluding the description of the flying qualities of this model, the author would like to clear up one point - namely, sinking speed. No doubt you've heard some of your friends describe the gliding angle of their gas ships, which in most cases seems to be the popular figure of 20-to-1. The author has noted the glide on all good gas models seen at recent eastern contests, and the best have shown a ratio of 6-to-1, or less. As you know, it is the sinking speed that turns precious altitude into minutes of flight time. Therein lies the reason for all the talk on SS, because that is one point in which the Rambler excels.

Are you interested in building this crate? Then grab your or pencil and dividers and get to Work right away by enlarging the plans to full size. After that's done, you can start on the actual construction.

FUSELAGE CONSTRUCTION: THE body is of conventional design, having a rectangular cross section; the entire frame is constructed of 1/4 in square balsa. In picking the strips to be used in the fuselage, try to use the straightest and most even-grained pieces that you can beg, borrow, or appropriate from your friends, enemies, or other model builders in your neighborhood.

You will note, on the plans, that the fuselage is symmetrical, making it easy to build. The similarity in shape between the top and bottom longerons produces an equal strain, so when you remove the built frame from the plans, the fuselage will not change shape.

Since the fuselage is so simple, it is not necessary to explain fully its construction. Note, however, that the top of the fuselage is filled in directly behind the wing with sheet balsa, to provide a mounting for the timer. A piece of 1/4 by 1/8 pine goes through the fuselage at the front to provide a point of attachment for rubber bands that hold the engine mount on. Before laying the fuselage aside, examine all the cement joints and make sure that they are sufficiently strong.

The motor mount consists of two bearers, 1/2 by 3/8 by 4-7/8, cemented and nailed with small brads to the plywood piece 'A' shown on the plans. Also nail on an upright piece of 3/8 by 1/2 at the rear of the triangular plywood piece. This upright is bolted to the Ys plywood bulkhead.

Cut two 10 inch lengths of 1/4 squares and cement a sheet bottom between them, making sure that the space between the 1/4 squares is over 1 5/16 to allow for shifting of the battery box. After cutting out two pieces of B, cement them to the 1/4 squares. And when dry, glue the whole works to the rear of the plywood bulkhead. Make sure that the battery mount is constructed of strong balsa as it must support the battery box.

On the rear of the plywood bulkhead, build up a rectangular section of 1/4 squares, so that the rectangle fits inside , the front of the fuselage frame. The rectangle is roughly 1/4 smaller in height and width than the bulkhead and the front of the fuselage, both of which are the same height and width. When this has been completed, the motor mount unit should fit snugly into the front of the fuselage. But if it doesn't, build up or shave away some of the mount so that it fits very snugly.

The landing gear is bent from 1/8 or 3/32 steel wire to the shape shown on the plans. Solder small brass fittings in the places shown, and drill them so that the landing gear may be bolted to the plywood bulkhead. Coat all joints in the motor mount unit with cement as a precaution against gas leaking in and doing its weakening work. A 1/4 by 1/8 pine strip should be cemented to the front of the bulkhead to provide anchorage for the rubber bands that hold the motor unit and landing gear in place.

THE WING : A TEMPLATE should be made first, by tracing the airfoil shown on the plans onto a piece of cardboard or .025 aluminum sheet. After cutting out the correct amount of ribs, the spar should be carved to shape. Bevel the ends of the center piece and taper the outer pieces from 1/8 by 3/4 to 1/8 square. Shape the trailing edge to the required triangular cross section and assemble the wing on a flat surface.

Cement the ribs in place and slide in the 1/8 square braces that extend through the center section of the wing. These braces are put in to keep the ribs aligned, because when the covering is applied the shrinking force would naturally tend to warp the ribs. Before removing the center section of the wing from your workbench, cement the tip spars to each end of the center one..."

Supplementary file notes

Planfile includes article.

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