Thursday, March 12, 2015

AMA Maxi Jr Free Flight Perfect From the Start

I was so lucky to receive a kit for what might be a very good second model for rubber powered free flight known as the AMA Maxi Jr. Searching for the kit on the Internet the website for RN Models was currently down, I did notice kits are available on eBay. This is a printwood kit in that pieces like wing ribs are printed on the wood, not die-cut or laser cut. To me the wood for the ribs felt heavy so I replaced just the ribs with lighter wood. The fuselage is a rather large piece of balsa but it appeared to be rather light in weight.  During construction and after covering I weighed the different structural components of the airplane, the end result was an airplane under 20 grams without rubber.

Update : Ken A. found this link to Penn Valley Hobby for the kit

Weight Breakdown
Fuselage 3.84 grams  
Stab 1.2 grams uncovered – 1.56 grams covered
Vertical Fin .65 gram uncovered - .74 gram covered
Wing 4.73 grams uncovered – 6.71 grams covered
Wing Mount  1.04 grams
Propeller 4.66 grams

Total Weight Without Rubber 18.96 grams

Another similar airplane I had built many years ago was the Air Hare which was a model class project for a couple of students, proportions were very similar and so are the flight characteristics. It is too bad the Air Hare kit is no longer available as that was a laser-cut kit. Both airplanes have fairly long fuselages which I think contributes to the pitch stability.

Air Hare on Left AMA Maxi Jr Right

Last evening was the first flights for the AMA Maxi Jr and it flew absolutely perfect from the first flight with absolutely no trim adjustments needed at all. Power is a single loop of 3/16” Super Sport Tan rubber which appears to be adequate power for a steady climb.  Unlike many smaller sport rubber models when the rubber runs out it glides fairly well and doesn’t go into a spiral dive.

From what I have heard from other people, everyone has thought this simple plane flies amazingly well.

Bill Kuhl

Video of First Flight

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