American Junior Hornet Goes Radio Control
This story on the Radio Control A-J Hornet appeared in the December, 2004 edition of Model Aviation Magazine. The story is written by Paul Bradley and is reprinted here with his permission.
Jim Walker's Hornet was great then and now. Awhile back I shared with you a fanciful project of mine involving the conversion of a reproduction Jim Walker 404 Interceptor folding-wing glider to RC. That was a fun project that has provided much small-field-flying enjoyment.
Frank Macy, the man behind the 404 Interceptor reproductions, makes another classic American Junior (Jim Walker) offering of the 1950s: the rubber-powered Free Flight Hornet.
I can't tell you how many American Junior (AJ) Hornets my brother Ralph and I had as kids. Thanks to those great RTF models, we had the opportunity to experience a model airplane that flew well. I'm not sure we would have stuck with the hobby without some of the reinforcement that came with each successful Hornet flight.
Having such a fond memory of the AJ Hornet, it was only a matter of time before my reproduction would receive an electric motor and radio gear. The pictures tell the story.
My choices of components for transforming the model into a small-field RC flyer began with selection of a suitable microreceiver. I used the RFFS-100 from Dynamic Web Enterprises. Another good choice is the JMP receiver (see source listing). It has the bonus of being narrow band. Both weigh roughly 2 grams and include a built-in 1.5-amp speed control.
To operate the rudder and elevator, I chose Bob Selman standard-size magnetic actuators. I used a Mabuchi N-20 motor coupled to a Bob Selman 4.2:1 gear drive. The gear drive that Bob sells for the N-20 motor is well suited to a project such as the AJ Hornet conversion. The propeller for this model is the same 5-inch Gunther unit that Chris Poole selected for his scaled-down Uproar.
In its Free Flight configuration—which includes the rubber motor—the AJ Hornet weighs 18 grams. The electric-powered RC version weighs 41 grams. You might think that the weight gained in the transformation would have a large negative impact on flight performance, but that was not the case. The RC Hornet is a wonderful small-field flyer.
I elected to use two Li-Poly cells in series. This gives plenty of power to let the model punch through wind and do simple aerobatics. My chosen battery has a capacity of 190 mAh. This gives flights in excess of 20 minutes. To use two cells with the RFFS-100 or JMP receiver, you need an adapter. These receivers are designed to operate on one Lithium cell. Bob Selman sells a two-cell adapter for each of the microreceivers mentioned.
After flying the RC Hornet, the idea of using it as an air-tow tug for the 404 Interceptor floated my way. At first I set the idea aside, thinking there would not be enough power to tow the Interceptor, especially because of the increased weight of the RC configuration.
The more I thought about this idea, the more I felt compelled to try it. As I write this, I have started the process of developing air-tow techniques for the Interceptor. My first attempts have demonstrated that the little RC Hornet has plenty of power for the job. I need to tune the towing geometry to get a more stable flight of the Interceptor while being towed, but this looks as though it will develop into a great backyard-flying adventure.
The RC Hornet and similar models are great for small-field venues such as a big back yard. That is where I like to fly mine. It is so nice on a calm evening to walk out to the backyard and do ROGs (rise-off-grounds) from the back porch. Life is good in the small-field-flying world.
Paul Bradley - 32238 Spinnaker Run, Magnolia TX 77354; E-mail: email@example.com
AJ Hornet: Frank Macy
RFFS-100 receiver: Dynamic Web Enterprises 159 Little Robin Rd. Amherst NY 14228 (866) Fly-Micro www.smallrc.com
Magnetic actuators, JMP receiver, N-20 motor/gear drive, two-cell receiver adapter: Bob Selman Designs 9054 Gum Rd. Carthage, MO 64836 (417) 358-9521 (after 6 p.m. CST) www.bsdmicrorc.com
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