Combining these two features helps to create an aircraft that will tend to stay in wings-level flight during straight flight and loops. They also help the pilot recover the aircraft from most turns. Fewer pilot corrections are therefore required in all of these flight regimes.

    Dihedral has other effects, but some are not so beneficial. It allows the rudder to be used to bank and turn the aircraft better, but too much results in a model that requires continuous aileron input to remain in a banked attitude. This is bad because it teaches a new RC pilot bad habits. On the other hand, a reasonable amount of dihedral, such as the three inches on Hangar 9's Alpha 60 RTF which is shown, adds a great deal to a trainer's teaching abilities.

    Power-plant selection is also important when studying a basic trainer. As far as I know, all RTF basic trainers that are powered by engines are two-stroke designs; these include Hobbico's NexSTAR, which is shown. If the pilot prefers to use a four-stroke engine, he or she must select an ARF.

    There are also a few electric-powered basic trainers. Some, such as Hobbico's SuperStar EP Select, which is shown, are complete, four-channel RTFs. Others, such as Horizon Hobby's HobbyZone Firebird Commander, also shown, are basic, two-channel RTFs.

    Engine-powered ARF basic trainers such as Midwest's Aero-Star 40 and Lanier's Explorer 40, which are both shown, offer the new RC pilot choices of radio system and engines that are unavailable in RTF models. However, this luxury comes at the cost of additional assembly work that could require basic model-building skills. RTFs require only that the new pilot be vaguely familiar with which end of the screwdriver points toward the work.

    The amount and type of assembly work involved in ARFs and RTFs (it's hard to call preparing those models for flight "building") is all that separates the two. As you can see in the photos, they look almost identical. And the two types do fly the same since there are few airframe-performance differences. There are performance differences, however, if the pilot equips an ARF with more powerful engines/motors and more capable radio systems than are usually found in an RTF.

    With the exceptions of the Hobbico NexSTAR powered by the O.S. Max .46 Fxi engine, the HobbiStar 60 Mk III using the O.S. Max .60 LA engine, and the Hangar 9 Alpha 60 equipped with the Evolution .61 engine, all RTF glow-powered aircraft currently use .40 cu. in. power plants. No matter how good a .40 might be, and all of today's engines are good, a hot .46 offers more performance.

    Except for the Hangar 9 Extra Easy 2 with the five-channel JR XF-421 computer radio system, all RTF basic trainers use analog four-channel radio systems for control. The NexSTAR does have an installed flight-stabilization system, which is similar to an autopilot but without direction control, but its transmitter remains a good four-channel analog system.

Click on photo to view large image with caption

Whether a pilot chooses an RTF or an ARF airframe as a basic trainer is his or her choice. Both offer excellent aircraft and performance. But as good as these aircraft are, there is always room for improvement and for pilot individuality.

    Next month I'll build an RTF trainer and make a few easy improvements. Following that, I'll look at the ARF world and show you how to make these fine aircraft look different and perform better.

    Until next time, you can review many of these aircraft on Sport Aviator, MA's online magazine, at www.masportaviator.com.   MA