Schoolboy (oz1030)

About this Plan

Schoolboy. Radio control gas model, for .010 power and 2 channel RC.

Quote: "Small R/C is really big - good power coupled with assured reliability of the small-transistorized receivers make the small one a must for every dedicated radio control man worth his salt.

As any Schoolboy will show you, the new Cox Tee Dee .010 glow engine puts out more than enough power to fly a hot little radio job. That is, of course, if the airplane is designed so that the power of the .010 is converted into useable thrust rather than a big blast against a firewall. So let's see how the Schoolboy figured this out and got into the air so soon after the engine was available.

The Schoolboy is designed with a long tapered nose, since the 3 inch diameter prop for the .010 Tee Dee has to have a fairly clear area behind it for the blast from that small a blade to have any effective thrust. Aside from this feature, the rest of the model is so conventional and straightforward that it almost needs no construction directions at all. It's about as simple as you'll ever see, but the pleasing lines and the hot performance will give you a real source of fun while you're building that big beautiful monster with 'steen channels - and it'll keep on giving you a thrill or two even after the big one is done.

The name is derived, of course, from the fact that the model can easily be flown in any normal sized schoolyard - although you should get permission first, naturally.

When I first heard that the LM Cox Company was going to market an .010, I naturally - along with a lot of others - wanted to see if I could come up with a successful R/C model for it. I'd experimented with the .020 a lot, had several successful designs, and knew the engine characteristics pretty well. I'd found out, for example, that with the little 3 bladed prop on the .020 flew my little seaplane with far more power than was required. This was a function of the engine placement up on the pylon above the wing, where the entire propeller disc was exerting effective thrust. I could probably have used that design, but I wanted something more along the classic lines of R/C.

So, using the basic layout of the proven cabin monoplane high wing design, I just stretched it out a bit, tapered the nose, swept the tail for the modern look, and in no time at all the Schoolboy was designed. The dimensions were set so that the fuselage would accommodate a standard Babcock compound escapement, a standard F & M Pioneer receiver, and two pen-cells for receiver power.

I built the model up rapidly, installed the radio gear, and mounted an .020 in the nose. All ready to fly, it weighed in at 10 ounces. There was no question of whether it would fly or not - I'd flown a similar model back in 1958 which weighed 15 ounces but needed a pretty-hot engine run to perform well.

The first flight on the Schoolboy proved the soundness of the design - both aerodynamically and structurally. Frankly I forgot, in my usual first excitement, and neglected to put the prop on backwards. I launched the model, it screamed up and over in a tight loop and banged into the ground - hard. It was easy to replace the prop and glue the firewall back in place. The tough part was trying to heal my wounded pride - somehow these models always have a way of whittling you down to size when you get overconfident, don't they?

The next flight I used better sense, put the prop on backwards (a 5-1/4 x 3 prop) and this time I was rewarded with a very nice flight. The model still needed some down thrust, and after I put that in it was a real joy to fly. Take offs were straight and fast, and the model handled very well. The only thing sensitive about it was the elevator. It does have to be adjusted carefully to the right neutral setting.

With this experience under my belt, I figured I had it about made. With the prop on backwards, the .020 was only developing about half power insofar as thrust was concerned; yet I had ample thrust. I put the model away until I could get one of the new .010's.

Since the .020, when it came out, amazed everyone with its power, which approached some of the old .049's, I figured the new .010 would probably do the same thing.

During a trip to Los Angeles, I was able to get to the Cox plant and tell Bill Selzer, the plant manager, some of my plans. They were shipping the .010's for release to the hobby shops, and he agreed that it would be good publicity to have an R/C job, so he presented me with one for my experiments.

The following weekend I had the .010 mounted in the Schoolboy and ready to go. Sunday morning, March 19th, I called my flying buddy in the Bay Area, Jim Wade, and out we went - 7:30 AM - to our 'private' field. I'd checked everything - radio, trim (reset to accommodate the slightly lighter weight of the .010 under the .020) and the engine, which really turns up like they say it will.

So what happens? Nothing! My booster battery is low, and I don't have a spare. I cuss, Jim commiserates, we confer. Solution - we head for Baylands park, where all the R/C guys fly, in hopes there'll be some other nut out that early from whom we can borrow a booster. Naturally, there is - several, in fact. We had to wait our turn, although as soon as they saw what I had, they cleared the air. I don't think they really expected that little .010 to pull this 'big' 36 inch model.

With a borrowed booster, then a prayer, the engine fired up like an angry mosquito. Jim took the model from me, went out about fifteen feet to avoid any swamping, I checked the controls, and Jim launched the Schoolboy. Off she went on as pretty a flight as you'll ever see. The .010 R/C was no longer a dream. I flew it around, looped it, rolled it, did everything I could think of, then when the engine ran out, brought it in easily. After that, we flew it until I had to leave to catch a plane to New York. For the record, we took some snaps with a Polaroid, which you saw in the June '61 issue of MAN.

Well, briefly, that's the history of the first .010 R/C. As for constructing it, you'll find it so conventional as to almost eliminate the need for explanation.

WING: The wing is standard single spar construction. Build it flat on your bench, cut it in two, glue it back together with dihedral braces at the center section, cover the center section top and bottom with 1/16 sheet, shape the leading edge, cover with silk, dope with butyrate dope, and it's done. About four coats of elope, slightly thinned, with a couple of drops of castor oil for each ounce of dope, yields a good finish. I used red silk with clear dope. Medium grade balsa is used throughout - wing, fuselage and tail.

FUSELAGE: This is the most complex part of the building process. Even so, it's simple. Cut the sides out of 1/16 sheet, glue the 1/8 square braces in place as they show on the plans along the top of the sides back to the rear of the wing mounting area, and the vertical braces at the respective stations.

Next glue in the bulkheads at the wing leading edge and escapement mounting and let them dry. Then glue in the cross braces at the trailing edge location of the wing. Be sure that the sides are glued together with the bulkheads at right angles so you'll have the right alignment..."

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