AMA Racer Re-visited

AMA Racer in Flight

Bill Kuhl ScienceGuyOrg

I noticed the local hobby shop had some AMA Cub and AMA Racer kits, I have plenty of AMA Cub parts from a bulk purchase so I bought an AMA Racer kit. In my basement I still have the first AMA Racer I built using the heavy plan material covering. My thought was to build the new one covering it with tissue, I also eliminated a small amount of weight by leaving off the small spruce piece used to hold the wing on with tiny rubber bands.

Frank Ehling, a legend in model aviation designed both the AMA Cub and AMA Racer. Wingspan of the AMA Racer is longer at 18” but because of the swept back wing it is skinny near the wing tips; that is not much surface area near the tips. Building the AMA Racer could be a little more difficult for beginners because of all the angle cuts required for surfaces that are triangle shapes. The AMA Cub had these shapes too but the joints were made by folding over the covering material at the tips so a proper fit was not so important. The beauty of the Squirrel design was that everything is a straight cut across the balsa strips which is easier for many beginners, Squirrel kits have the pieces laser-cut now.

Completed Frameworks Ready for Covering

To build the AMA Racer I covered the plan material with wax paper and held the strips down with push pins stuck into a piece of ceiling tile, conventional model airplane construction technique. Tissue paper was attached to the balsa framework with glue stick. Spruce strip is used as a tail boom in the AMA Racer, gluing this to the front of the motor stick gives the negative incidence in the stabilizer. This plane has the normal V-dihedral so you want to get a good glue joint in the center of the wing because of the stress there. I glued the wing to the motor stick and left the nose portion of the motor stick plenty long, cutting it off to achieve proper balance. If I can avoid adding weight for balance I try every trick possible first before adding weight.

Flying the AMA Racer is fun in that it flies slower than some other models of this type yet it climbs easily on 3/32” rubber strip. The AMA Racer can be purchased from Sig Manufacturing or AMA is selling individual kits of the AMA Racer also.

Note:  Dave Gee that is on AMA Education committee suggested that the AMA Racer flies better if you cover the bottom of the stabilizer instead of the top. This would also give a wood to wood joint instead of wood to tissue.  I plan to try this on another AMA Racer.

 


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