PT-40 (oz8015)

About this Plan

PT-40. Radio control sport trainer, for .40 engines and up.

Note the PT-20 (oz8014) and PT-40 were two sizes of the same trainer model design, essentially. They both featured in the same RCM article.

Later kitted by Great Planes.

Quote: "RCM presents a pair of primary R/C Trainers for beginners that are superb fun fliers too - the PT 20 and the PT 40. By Stu Richmond.

Remember when you were just learning to fly? If only you had a forgiving model. If only things happened a little slower. If only the model would have taken a greater pounding. If it would have just righted itself - these models will!

R/C Modeler Magazine urges you, our reader, to bring this pair of models to the attention of your friends and spectators who are thinking about getting into R/C. And if you want to drift around the sky with your new 4-cycle running leisurely or compete and win in fun-fly contests with climb/glide, limbo, spins, etc, these models can be for you!

The P.T. 20 is ideal for a Saito .30 or smaller 4-cycle engine, as well as .15-.20 2-strokers. The P.T. 40 is ideal for any of the current .40 site 4-stroke engines up through and including the .60 sizes, as well as .25 to .40 2-strokers. The object of this design was to have a non-ballooning, non-zooming R/C model in a choice of two sizes that a beginner could readily learn to fly - and to have a superb fun-fly winner in the hands of a competent flier - with lots of fun in-between! The object has been achieved and these are yours to enjoy. This design is dead simple to build, has relatively few parts to cut out and is immensely strong.

The P.T. 20 and the P.T. 40 have both been flown with a variety of engines (they're great with 4-strokers) - they hand launch very easily, loop readily, barrel roll well, spin gently to the left, fly inverted, and can be coaxed into one outside loop. They'll land at startlingly slow speeds and even handle cross winds well on a paved runway. My two prototypes do not have a steerable nose gear - but they steer beautifully on take-offs and landings - touch and go with ease - but for slow speed taxiing if you fly from a paved runway you can readily add a steerable gear of your choice selected from many available to RC'ers. The designed purpose of the nose gear is simply to protect the model when landed by a beginning RC'er!

The 'break-away' engine mounting plate is a useful safety feature that helps protect your engine. Also, it makes changing engines a snap. My P.T. 20 has had an H.P. .21 4-stroke in it, an Enya .19 2-stroke and is presently flying with a simple, super reliable idling O.S. .15 R/C 2-stroke engine. The P.T. 40 carries a Saito .45 4-stroker that is proving to be my personal favorite engine of all time! It's great on 4-cycle fuel, is happiest on home-brew of 10% castor oil, 20% nitromethane and 70% methanol and the more I run it, the better it gets! But I might try my vintage twin cylinder inline Taplin Twin British Diesel just for fun. The engine mounting plate does have advantages. So pick the site of P.T. you want to build..."

Supplementary file notes

Article pages, text and pics, thanks to hlsat, JHatton.

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