Square Trainer (oz12628)

About this Plan

Square Trainer. Radio control trainener model. For .40 power.

Quote: "Here's a scratchbuilt trainer for the beginning R/C pilot, one which will help get you into construction with complete, step-by-step instructions. And it's a good flier too!

Twenty years ago the R/C world was well-stocked with trainer aircraft that, were inherently stable. These were the 'left over' escapement-controlled planes that were the standard 1950/1960 radio con-trolled models. As proportional control took over, the experienced escapement flyers graduated to that type of control. DeBolt Trainers, Esquires, Smog Hogs, Rudder Bugs, etc were easy conversions to proportional control. While not always slow flying because they depended on high wing loading for penetration into the wind, they were inherently stable, ie hands-off they would return to the normal level flight.

As these models flew into the sunset, the beginner was forgotten as the more experienced flyers demanded faster, more maneuverable aircraft: that would defy the novice's abilities. However, many of these designs were advertised as trainers if one put a smaller motor in them. At that time, there were no real trainers being kilted. The writer became noisy in this respect and had a letter-to-the-editor or two published on the subject. Still nothing happened. After some correspondence with Bill Winter, the author designed the Junior Trainer (oz12543) published in the Jan/Feb 1973 issue of the Junior American Modeler). Actually, the Mark I Trainer was designed first but Bill thought it too fancy for the junior novice. This design was published in the March 1973 issue of Model Airplane. News, Subsequently a number of trainer. designs were published or kitted, Here again, the experienced modelers. who designed these (myself included) tended to think in terms of a combined trainerifun fly model. One goal was to produce a model that would not be "outgrown," quickly. This approach did the novice no favors in the writer's opinion but is still the approach used in many of the trainers. being sold today.

A word should be said for the argument that the best trainer is a four-channel, semi-symmetrical winged bird. Those who argue for this approach point out that the slower flat-bottom winged bird can lose its utility quickly as a novice learns to fly and wants a more agile craft. To this argument we say that there are mighty few novices who can get the necessary instructor time to learn to fly using a four-channel bird. It takes a heap of learning (for most of us) to get to the point where one can completely solo this type of aircraft. If comprehensive tutoring is available, it may be possible to go this route. The slaw trainer provides good building experience,, forgiving flight characteristics and the reaction time necessary for a novice to pick up the feel of radio control flying. If you are talented enough to learn to fly R/C quickly and truly outgrow your slow trainer; don't despair! Your aircraft can be passed along to another beginner or used for such projects as: photo taking, glider towing, and float flying.

The type of aircraft we are discussing in this article is illustrated by Ramco's First Step, Hobby Lobby's Telemaster Goldberg's Eaglet, Sig's Kadet and Kraft's Trainerkraft 40. These aircraft are kitted and relatively simple to build. If you can build well, try an R/C assisted Old Timer or a model like John Laycock's Cavalier (May 1984, Model Aviation). Incidentally, most powered gliders do not make good trainers. Their flat glide and slow control reaction time makes them uncharacteristic of other powered aircraft. You will have enough trouble getting a lightly loaded powered aircraft to settle in for a landing on a warm day - the glider may fly on and never let you practice touch and goes.

If you are game for a real learning experience, read on - a scratch-built trainer may be for you.

DESIGN FEATURES: The Square Trainer is an inherently stable, slow flying aircraft that: is easy to fly. It is not very aerobatic. The characteristics that make a good stunt. aircraft are exactly what a novice doesn't need: in the hands of a novice these characteristics lead to early disasters! The model will accept a range of two-cycle engines from .30 to 45, and is ideal for a 40 four-cycle. Any radio of three or more channels will work, servos in the small to large sizes will work just fine.

The landing gear is widestanced (main wheels wide apart), for greater stability on the ground (especially under windy conditions). The nose wheel is not steerable, but casters freely in response to air rudder steering. If you fly from a. smooth field or asphalt, a straight legged, steerable type can be used. Rough fields are very hard on servos used to steer a nose wheel. Tail dragger gear is not recommended for novices. Nose gear protects the propeller and positions the model for easy takeoffs. Note the bumper under the stabilizer to protect it from nose high take-offs and landings.

The general configuration of the Square Trainer borrows from many sources among them: Bob Machado's First Step, the M.E.N. Buzzard Bombshell and the author's early trainer designs. It has low wing loading to make it fly at slow speeds and long nose and tail moments to make it directionally stable. The wing has moderate dihedral for easy turns and' the inherent capability to return quickly to straight and level flight from most any attitude.

Perhaps the major design feature in the Square Trainer is its simple construction, Each step in the design was thought out to compromise: ease of construction, good flight characteristics and the ruggedness needed..."

Direct submission to Outerzone.

Supplementary file notes

Article.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction