AT-6 SNJ (oz6336)

About this Plan

AT-6 SNJ. Sport scale model for radio control.

Note also kitted by Aero Precision.

Quote: "AT-6 SNJ by Bryce Petersen. A semi-scale version of the North American Harvard II designed for the Graupner/OS Wankel engine. Pattern performance on a .29 to .40.

Hello, again, It has been some time since I could join you with a model project. The opportunity presented itself to start a new club here in West Virginia, so I have spent a year or so plunging into the various chores of club activities and training new members. Membership is up to 30 proud, dues-paying members with five competent instructors with 'ready thumbs' to help the beginners. This year's election produced eager, new faces and I was allowed to settle back into the background and design models again. We are known as the Mountaineers of Charleston, West Virginia, and all of us extend the invitation to come fly with us.

AT-6 SNJ North American Harvard II. This aircraft needs no introduction to aviation-minded persons. It was the basic trainer for the Army and Navy, produced after the second World War because of its excellent handling characteristics for training. It was first ordered in 1938 by the RAF. The popularity of the Harvard [1 soon spread to the U.S. and over ten thou-sand were produced in the U.S. and Canada. The design possesses the dis-tinction of having been manufactured in larger quantities than any other basic trainer.

The model presented here is a semi-scale SNJ. It is close enough for stand-off scale events and actually won first place this spring at a contest. The head judge suggested I add instruments and rescale the ailerons for more points, however.

The real plus for this model is its ability in the air. The power, drag, and wing loading ratio is close to perfect. The first few flights were a thrill for me, l found myself doing things that are normally difficult for me. For example, I can pull the stick back, and it will do a round loop. With a touch of down trim, you can roll it upside down and it just stays there. Slow it down and point its big nose up into a stall and plop, straightforward to recovery. I went charging into an eight point roll and to my surprise, l did it. I am so impressed with its flight characteristics I plan to enter it in pattern next month. For a 030 powered scale model that brings the 'oohsh and 'aahs' on the flight line, then flies like it does, I am quite proud of this one.

It has been amazing to me how much trouble some designers go to designing scale models. Why do they make things so difficult to construct? The average modeler is interested in a model that is realistic and flies well. l looked at some of the all-balsa scale models at Toledo this year, and I wonder how many of these kits will be completed and flown by the builder. I believe the modelers of the near future will demand scale appearance even in the beginner-trainer kits.

The model presented here was designed for flight performance first and scale appearance second. Construction is as simple as the average slab side square-tipped monster, but in my opinion, it looks like a real airplane. In order to transmit the construction techniques that I think are easy for the prospective builder, I have added key photographs to answer questions the plans fail to show. I have found that it is almost impossible to communicate with drawings, little ideas that are so easy for the experienced builder and seem to confuse the beginners.

Let us start construction by cutting two fuselage sides from a good grade of medium hard 1/8 in balsa. Lay them on a flat table and trace your 1/32 in plywood doublers. Epoxy the doublers to the insides, Cut two hard-wood dowels to length and the 1/16 in plywood center section (F1) that extends into the cockpit area. This extension forms a base for mounting a pilot in the cockpit area. Cut the 1/4 in plywood firewall and sand all rough edges smooth.

On a flat table, turn the fuselage sides upside down and slide the two dowels in place. Slide F1 in place and add the firewall. This will form a box-like structure and every-thing should fit squarely. Epoxy these parts together except for the dowels. The latter are epoxied after the 1/16 in sheet sides are in place. Draw a straight line on your work table and a center line on the fuselage... "

Hi Steve - Here is Bryce Petersen's AT-6 SNJ from RCM magazine issue 09-71.

Direct submission to Outerzone.

Update 19/05/2021: Added kit review from Flying Models, September 1974, thanks to RFJ.

Quote "A Trade Winds Special Review: Aero Precision's AT-6 Texan, by Frank Tiano.

Here is a review of Aero Precision's all balsa kit for the popular AT-6 Texan, a good kit but one that must be balanced correctly before you attempt to fly it!

The AT-6 Texan, manufactured by North American Aviation, has been called the most universally used airplane in his-tory. It was the classroom from which most World War II Allied pilots graduated to the real thing: Thunderbolts, Spitfires, Corsairs, Hellcats, Mustangs and Light-nings. It was designed to provide the best possible training in all aspects of military flying including ground-strafing, dive-bombing, dogfighting, aerial photography, flexible gunnery, and it carried most of the equipment which pilots of the period had to operate, Lieutenant EC Dickson, the most decorated Navy flier of the war, called the SNJ version the best scout trainer in the world.

The Texan model represented in the following review is manufactured by Aero Precision Inc., PO 152, Tipton, IN 46072. It's called a high performance, semi-scale model for .29 to .40 sized engines. The price of this all-balsa kit at the time of this writ-ing was $38.50. Usually in our Trade Winds Reviews we give a general set of direc-tions to aid the reader in assembling the kit. However, except for a few isolated areas, this kit may be constructed by any-one with even a little amount of previous building experience. That statement doesn't hold true for the flying part of this airplane, though. The plans are very com-plete as are the directions and bill of ma-terials. Since the "Texan" is a Bryce Peter-son design, construction may be a little unorthodox at times.

Construction: Before starting actual construction, fa-miliarize yourself with the plans and direc-tions thoroughly. Next, sand the backs of all the die-cut balsa sheets to make the parts easier to remove. If your kit is any-thing like mine was, die-cutting left some-thing to be desired, especially for the wing ribs. It might be a good idea to make your-self a wing jig like the one shown on the plans to make certain that no warps will creep into the structure while building the wing panels. The overall quality of the wood in the kit was good with the excep-tion of the wingtip blocks which were of very different weights and grain. The only other area of discrepency was with the formers which were band sawed but had different shapes on either side of their centerline.

The fuselage is built using the standard 'box' method. Plywood doublers are first cemented to the sides and then the formers added. After the basic box has been com-pleted, cement the little half-moon for-mers to the outside of the fuselage sides. These are then covered with 1/16 sheet balsa to obtain the proper fuselage round-ness. What you have, in effect, is a fuse-lage with two sides on each side. I suggest that you don't add the plywood canopy braces until the entire fuselage is com-pleted as they are prone to being knocked off while handling the model.

The fin and stabilizer are sheet balsa while the elevators and rudder are built up and covered with whatever material you prefer. A word of caution here; be-cause of its short nose moment and long tail moment, this aircraft is prone to be a little tail heavy, so make every effort pos-sible to keep the rear fuselage and tail surfaces as light as can be. With careful use of the glue and generous use of the sanding block you can almost eliminate this problem.

The wing is built up of ribs and spars and is sheet covered. There are three wing panels: a center section and two outboard panels. The dihedral brake is approximately six inches on each side of the cen-terline of the center wing panel. Be sure to use plenty of epoxy in these areas. I chose to install torque rods for the ailerons in-stead of the bellcranks shown on the plans. I also decided to strengthen the center section trailing edge of the wing so I could use wing holddown bolts instead of the rubberband method for attaching the wing to the fuselage as shown on the plans. After completing the wing construction, I cov-ered the entire surfaces with Trico fiber-glass cloth and Trico resin. Because it weighs only .7 ounces per square yard, I was able to increase the strength of the wing without adding weight of any conse-quence.

All that's left to do at this stage is to fit the balsa cowl to the engine you're us-ing and cement the tail surfaces to the fuselage. The plywood cockpit braces may be added at this time also, along with two pilots and instruments if you chose to use them. The canopy may be installed now. You'll notice that the canopy is very much oversize to allow you enough material for trimming and fitting..."

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