Beginners Guide To Flying RC Airplanes ebook

Gas RC trainer airplanes
(glow plug/nitro)

Gas rc trainer airplanes ('trainers') are designed to make learning to fly as easy as possible and all trainers - regardless of power type - have the same basic characteristics. The most obvious of these are the high wing design and noticeable dihedral, which is the term that refers to the upward 'V' angle of the wing panels when viewed from the front.

This high wing / high dihedral configuration gives a trainer a lot of natural stability in the air which, generally speaking, results in very forgiving flight characteristics - exactly what you need when learning to fly radio control airplanes!

Gas rc trainers are typically designed around the '40' or '46' size (.40/.46 cu.in) 2 stroke glow plug engine and are 4 channel with control to throttle, aileron, elevator and rudder. The wingspan will typically be around the 60-70 inch mark.
Incidentally, the word 'gas' although short for gasoline is also often generically used to describe all internal combustion (IC) powered rc airplanes, but for the sake of this page we're just referring to the most common IC power type; glow plug, sometimes also called 'nitro'.

Such rc trainer airplanes can be purchased in kit form or RTF/ARF (Ready To Fly / Almost Ready To Fly). RTF airplanes are the better choice if you have no desire to do any model building and you just want to get flying as quickly as possible. The primary differences between kit, ARF and RTF are:

Kit: the plane needs building from a box of pieces, over a plan. You'll need to purchase quite a few extras and tools and have a good knowledge of model building techniques. Building from a kit is ultimately very rewarding.
ARF: the plane will be about 90% finished, just needing some final assembly work over a few evenings. You need to install the engine and radio gear yourself, having bought it separately from the kit (Learn more about ARFs).
RTF: the plane is completely finished, with motor and rc gear fully installed. You just need to buy batteries for the rc gear and do some very basic final assembly (Learn more about RTFs).

So you can see that an RTF gas rc trainer airplane is the best choice if you just want to get flying with the least amount of fuss and in the shortest possible time, but an ARF or kit is a better choice if you want to learn more about the construction side of the hobby.

Shown below are just a few currently popular gas rc trainer airplanes...

Hanger 9's trusted Alpha Trainer gets a revamp with this new edition; the same basic features as its predecessor are there but the big difference is that this plane comes with the latest 2.4GHz DSM2 radio technology, for interference-free flying. Read more...
This NexStar Select 46 from Hobbico is packed with unique features to help you get flying as quickly, easily and safely as possible. Fully RTF and a great introduction to gas rc airplanes. Read more...
A Piper Cub like this one makes an excellent scale trainer airplane, and is a popular subject. Modeled from a real-life trainer, the Cub is very stable and forgiving in the air, making it easy to fly. Search for rc Piper Cubs.
An exception to the high wing rule, this P-51 Mustang PTS Trainer is a scale warbird that's been tamed to fly slower and more stable than such airplanes usually do. Sold as a legitimate gas rc trainer airplane, this is an excellent alternative to the norm. Read more...

See these gas rc trainer airplanes in more detail.

Why high wing airplanes make the best trainers

High wing gas trainer Most rc trainer airplanes have a high wing for one simple reason - stability. In a high wing plane the weight of the fuselage below the wing will always act to stabilise the model in flight. After a turn, for example, the plane will naturally want to level itself because it is 'bottom heavy'. Airplanes of this design are therefore perfect for the novice radio control pilot.

Low wing gas trainer airplane Low wing designs are of course the opposite; the airplane is 'top heavy' because the fuselage is above the wing and so the plane will not want to right itself so much. For this reason, planes of a low wing design aren't as stable as high wing planes, but they are more maneuverable. There are some low wing trainers available of course, like the Hanger 9 PTS Mustang, for example.

Mid wing gas trainer rc airplane Between the two there are the mid wing designs, where the wing is located approximately halfway between top and bottom of the fuselage. These airplanes give a good balance of stability and maneuverability and are perfectly suited to smooth aerobatic performance because of the generally symmetric design. The 'Extra' is a well known mid-wing airplane, but not really a trainer!

Other factors to consider...

Wing shape

When choosing between model rc airplanes, wing shape (airfoil or aerofoil) is another factor to consider. This airfoil section is the shape that you see when looking at the wing 'end-on'. Although there are many different specific airfoil designs, all alphanumerically labelled, there are basically 3 common categories that you're most likely to experience in your early days of flying radio control airplanes - flat bottomed, semi-symmetrical and symmetrical shaped airfoils.

Put simply, an airplane with a flat bottomed airfoil will have the most lift at the slowest airspeed - obviously good for the beginner and the reason why many trainers feature this shape.
A symmetrical airfoil provides equal amounts of lift regardless of whether the plane is right-side up or upside down - perfect for aerobatics.
An airplane with a semi-symmetrical airfoil holds advantages of both flat bottomed and symmetrical, so is ideal for the 'sport' type planes.

These 3 common airfoil shapes are (very approximately) illustrated below:

Some common airfoil shape categories of a wing

Two other airfoil sections that you might encounter are under-cambered and flat. An under-cambered wing has its lower surface closely following the curve of the upper surface. Such airfoils are very efficient and create little drag.
The flat wing section has become increasingly common in recent years as more people build electric rc airplanes out of foam sheet, particularly Depron. The indoor 'shock fliers' are a good example of planes that usually feature a completely flat airfoil. You almost certainly won't see a flat airfoil section on a gas rc airplane though.

Dihedral

Dihedral is the upward 'V' angle of the wings from the fuselage, looking at the wings from the front. Greater dihedral increases the airplane's stability, up to a point, as the plane will naturally want to center itself to its lowest point. Model airplanes that are designed for aerobatics will have very little or no dihedral, so maneuvers can be executed without the tendency for the model to keep righting itself.
Planes that are designed to be trainers will always have noticeable dihedral.

Landing gear (undercarriage) layout

While some models have no landing gear, there are two choices otherwise; tricycle or taildragger.
Airplanes with a tricycle landing gear ('trike') have two main wheels beneath the cockpit area and a nose wheel, which may be linked to the rudder servo to give accurate steering control on the ground. The trike undercarriage plane is, generally speaking, easier to maneuver on the ground, making it better suited to beginners.
A taildragger has the same two main wheels but instead of a nose wheel has a much smaller wheel located beneath the fin, which may or may not be steerable. Taildraggers can be harder to maneuver on the ground but the lack of nose wheel means slightly less weight and drag in the air.
Of course, the type of landing gear will be determined by your choice of plane - for example, a Cub will always be a taildragger whereas most non-scale trainers will likely be trikes.

So hopefully this page has given you an idea of what a trainer airplane is. It's important that you consider this type of airplane as your first and that you don't rush out and buy something unsuitable for learning on. The correct choice of your first rc plane is going to have a profound effect on your enjoyment of and success in the hobby of radio control flying!

See the gas rc trainer airplanes on this page in more detail.

Gas rc airplanes - a general overview of planes available today.