IN THE FIRST article of this portion of MA's "From the Ground Up" series I reviewed RTF and ARF aircraft that are suitable for new RC pilots. The second article covered building a generic RTF trainer, using available glow- and electric-powered versions as examples. You can assemble RTF trainers in 20 minutes to an hour, using common hand tools. No adhesives and few building skills are required.

The contents of a typical ARF kit. Most of the hard work is already done for you.

    RTF trainers represent a leap forward for beginning modelers. It is possible to get into the air with a quality aircraft in less time than was once required to unpack a wood kit. Still, constructing a wood kit has several advantages that RTF pilots miss, one of which is that it allows the pilot to select an upgraded radio system and engine.

    Building a wood kit allows the pilot to modify the airframe to increase performance, appearance, and durability. Wood kits allow the modeler to "swap out" heavy parts by making identical parts from lighter wood. Built-up wooden kits are usually 5%-10% lighter than the identical ARF. Less weight makes any sport aircraft fly better.

    Constructing a wood kit is also fun and educational. This series will eventually cover how to build a wood-kit aircraft "from the ground up." Every model pilot needs to gain this experience, but constructing a wood kit has two drawbacks: it takes one to two months to complete and requires advanced building skills.

An extra servo, stronger nose gear, a few pieces of wood, and covering material (not shown) are all you need to improve the Hobbistar's handling and durability.

Use 30-minute epoxy to join three wingspar parts. Tack pieces to flat building board or clamp to large combination square.

    Surely there must be a compromise between RTFs and wood-kit models. There is, and it is an "ARF."

    ARF aircraft require some building skills, but nowhere near those required to complete a wood kit. ARFs come in enough pieces that the builder can make almost as many modifications as he or she can when building a wood kit.

    The pilot supplies the radio and engine systems, allowing upgrades. So much work is factory-completed that the average ARF trainer requires just 20-25 hours to go from box to air. Almost the only advantages left for a wood kit are its lighter weight and unique appearance.

    There are far more ARFs available than the relatively few RTFs. It is impossible to include every ARF in this installment, as I did in the June issue with the RTFs. Instead, in the next few "From The Ground Up" articles I will cover building and modifying one ARF trainer: Hobbico's Hobbistar 60 Mk III.

    This 60-size advanced trainer features a semisymmetrical-airfoil wing, allowing inverted maneuvers. However, the generous wing area and dihedral give the Hobbistar basic-trainer abilities as well.
 
    If you want to learn about many other fine ARF trainers available, you can read about them in MA's Sport Aviator online magazine at www.masportaviator.com.  

Apply epoxy inside aileron torque-rod hole and along channel. Epoxy strengthens wood around torque rod to prevent flutter. Epoxy in channel fuel-proofs exposed wood.

Note hinge center mark where 3/32-inch hole was drilled in both surfaces. Two pins align hinge during installation. Remove pins just before gluing hinges.