Step 1 - Primary Trainer
A primary trainer is a High-Wing, stable model with self-correction capabilities. It should be as large as feasible - generally .40 size. Self-correction is important because it allows the aircraft to attempt to right itself if the beginner loses orientation and releases the controls. The stability comes from the wing location and a large amount of dihedral.
Desirable Properties of a Primary Trainer
Most of the weight in a model is the engine, radio equipment, fuel and landing gear. The high wing location puts all this weight below the wing which naturally makes the aircraft want to fly upside up.
Dihedral makes the model want to fly with its wings level. If the aircraft is banked and the controls are released, the model will naturally want to return to flying with the wings level.
The flat bottom airfoil does not aid or hinder stability. It is a special high-lift airfoil that allows the model to fly slower. Conversely, a symmetrical airfoil must fly faster to maintain its altitude. Therefore a flat-bottom airfoil is best for a trainer because it allows the beginner to fly a slower model.
The wing incidence and decalage, if designed properly, make the aircraft naturally want to fly at a level attitude. If the model is diving and the controls are released the model will return to level flight.
Note the word, naturally, is the key word here. That's what makes a good trainer a good trainer. It's the fact that the model wants to fly straight and level and will attempt to return to straight and level flight if the beginner does nothing at all. Of course all of this depends on the aircraft having enough altitude to recover which may take as much as 200 feet.
As a beginner you should start training yourself to pull the throttle to low and releasing the controls as soon as you realize you are not in control of the model. Because you have an instructor, you should also immediately tell him that you are in trouble because he may not know and think whatever the airplane is doing is something that you are doing on purpose.
Why You Should Build Your Own Trainer
Building your own trainer will teach you rudimentary building skills in an aircraft that is less critical of errors. Trainers tend to be over-built so that they can still be considered flight-worthy even when there are multiple construction errors.
However, I do not intend to give you the belief that you should ever attempt to put a questionable aircraft in the air. A Radio Control model airplane can be very dangerous - lethal even. In fact, there are many hazards associated with this hobby. Please be safe.
Additionally, even ARF's need to be repaired from time to time. It is important that you understand what is under the covering and what it does. Building your own trainer will give you the fundamental knowledge you need to make basic airworthy repairs.
By the time you finish your first trainer you should have a few tools to get started on your next build.
Specific Primary Trainer Recommendations
For your primary trainer, I recommend any of the following aircraft. Note that Sig has a really screwy website and I can't link to the individual aircraft. To find them, enter the Sig website. Then click Aircraft, Aircraft - R/C Kits, Trainers and select the trainer you want to view.
All of these models are lightweight, excellent flying aircraft. The Sig Kadet MK II is probably the most durable of the models mentioned here as well as the heaviest.
There are other primary trainers available and I have yet to come across a .40 size trainer that I would specifically not recommend, but then I have not looked closely at what is currently being offered either.
By the time you graduate your primary trainer you will have learned:
- Basic building skills
- Properties of a variety of materials and adhesives
- Basic airframe covering skills
- Basic aerodynamics
- How to pre-flight and post-flight your aircraft as well as general maintenance
- Radio and Control adjustment
- Radio battery maintenance
- Flying field etiquette
- Basic flight skills including taxiing, flying a circuit, setting up and landing and basic emergency recovery
- How to trim a model aircraft for straight and level flight
- Basic engine tuning and maintenance