Curtiss O-52 Owl (oz11776)

About this Plan

Curtiss O-52 Owl. Free flight scale model, for Ohlsson 19 or similar engine.

Quote: "GAS MODEL ARMY SCOUT. A scale model of the Curtiss O-52 observation plane that is easy to build-and a most consistent filer by SYDNEY STRUHL.

THIS month we are presenting a most unusual gas model - a truly scale version for either Class A or Class B motors of the United States Army's new eyes: The Curtiss O-52 observation ship.

The Curtiss O-52 is the Army's latest flying 'greenhouse' used extensively for observation and reconnaissance work, artillery spotting, and on photographic missions. The crew consists of two: the pilot and observer. Naturally the ship's performance and other details are Army secrets, but it is said the O-52 is considered one of the most efficient aircraft of its type in the world.

After glancing at the pictures of the Curtiss O-52 you can readily tell that this type of plane would make the ideal scale gas model. And believe us it does!

The general setup of the whole plan lends itself to a very stable model. The high wing, ample dihedral, large tail surface area, well placed thrust line, and a rather nice setup of all forces such as the center of gravity and center of lateral area, etc, all combine to present a very pleasing picture of what the well-flying gas model is sporting this year.

Certain structural features are well-noted, too. The landing gear placed well forward insures fine landings and prevents broken propellers. The fuselage design allows us to employ the well known 'crutch construction' that simplifies fuselage construction to a great degree.

The O-52's construction may appear rather difficult at first glance, but after a little study of the plans you will realize that this model is amazingly easy to build. We have tried to keep construction easy enough for the beginner who is trying his hand at a gas model for the first time. Of course one of the big features of our Curtiss scale gas model is the fact that we are employing the new Grant wing slots. There are several reasons why we decided to use these new slots in the wings. The model has a rather high wing loading which means that flights will be quite fast: naturally you don't want a sensitive model: therefore the wing slots. Although the tail surfaces were designed with plenty of area, the fuselage moment arm is rather short. When the wing slots are used they eliminate the need for a long moment to produce a stable flying model. Slots also go a long way in producing a long, flat and very slow glide. All of these facts and claims about wing slots have been proved by the designer, the editor of Model Airplane News, Mr Charles H Grant.

The model is large enough to take either a large Class A or B motor. The author used an Ohlsson 19 to power his O-52 and there was enough power to pull his model quite high on a twenty second motor run. Evidence of the flying ability of the model is that although it was always flown just before sundown when most of the thermals had died down, flights of several minutes were common and are now taken as customary.

The author has tried to adhere to true scale throughout and only very minor changes were made to insure stable flights. It is suggested that you fly without the single wing strut shown in the front view; the extra drag is not compensated by the appearance. If you wish to use the strut use dress snaps to keep it in place.

You will note that the plans are drawn to a very convenient scale of 1/3 to the inch. Therefore all you have to do to obtain full size drawings is to enlarge the magazine plans three times. Too make your task still easier we have supplied full size drawings of the fuselage bulkheads, wing ribs, tips and other important parts.

Well, that's enough talk about the Curtiss O-52. Now how about buckling down and see just how fine a job you can make of it?

FUSELAGE: The fuselage is constructed with the use of a main crutch and a sub-crutch. The main crutch is shown in the fuselage top view. This is made from 1/4 in sq strips of balsa. Note that the hardwood motor mounts are attached to the main crutch. Fill in around the motor mounts with 1/4 in soft sheet balsa. While cement is drying on the main crutch make the sub-crutch. This is made from 1/8 x 1/4 in strips and cemented firmly together. Cut the piece S-C from 1/4 in sheet and cement to the front of the sub-crutch.

Now connect sub-crutch to main crutch as shown in the fuselage sketches with 1/8 x 1/4 uprights. Be sure to keep dimensions correct as given in the side view. Finish the top of the fuselage as shown. Lay the two 1/8 square fairing stringers on each side of the fuselage as shown. Cut all fuselage bulkheads as given in Plate 3 and cement them all in their proper locations.

Bend the single-strut landing gear strut from 3/32 steel music wire to design shown and attach it to a 1/16 thick piece of plywood cut to the shape of lower section of bulkhead D. Cement this to the bulkhead with several coats of cement. Add the lower 1/8 square stringers to the bulkheads. Note that the very bottom stringer is 1/8 x 1/4 rather than 1/8 square. Attach a small tail wheel to the 1/8 x 1/4 stringer with several coats of cement and bind with thread.

Fill in between bulkheads C and D with 1/8" soft sheet balsa. Note that bulkhead D' is not cemented to D; and sandpaper perfectly smooth to simulate the cowling. Insert lengths of 1/8 hardwood dowl to wrap rubber strands on to keep the wing and tail section in place. Cut all necessary holes in the cowling to accommodate your individual motor. No battery box and coil position is given in the plans because these are placed along the main fuselage crutch at points that will balance the model at about the 50% wing chord mark. Note that bulkhead J' is cemented to the center section of the wing and not to the fuselage; this forms the fuselage fairing into the wing..."

Direct submission to Outerzone.

Supplementary file notes

Article, thanks to GTHunter.

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