Plans-Built, e-Powered Carl Goldberg Junior (Jr.) Falcon

As published in the July/August 1963 issue of American Modeler magazine, Carl Goldberg Models released a ½A-powered version of their highly popular Falcon model airplane - the Junior Falcon (aka Jr. Falcon). Having always been a fan of Goldberg models, I decided to build a Jr. Falcon from plans. I was originally going to use a Cox .049 engine for power, but ultimately decided to go with electric power since glow fuel has gotten very expensive. The resultant 4-channel Jr. Falcon has a 480 brushless motor, ESC, and a 3-cell, 380 mAh Li-Po battery pack.

The photo to the left shows the Jr. Falcon at the end of is maiden flight. I flew very well, but was also very fast due to the relatively high wing loading. Its 37" wingspan and 6-3/4" chord for a 250 in² wing area. The specified flying weight with a single-channel escapement R/C system is 16 oz., which resulting in a wing loading of 9.2 oz./ft², which is quite reasonable.

My Jr. Falcon, with the 480 motor, esc, receiver, and three servos came out at 20.0 oz., for a wing loading of 11.5 oz./ft². The semi-symmetrical airfoil adds to the flying speed, as compared to the 1/2A Skylane, with its flat bottom airfoil.

No being particularly happy with the flight flight speed, I decided to do a weight reduction and wing area increase in order to get the wing loading down. The ailerons were not very effective, so I removed the servo and hardware and glued the ailerons to the trailing edge. 4 inches was added to the wingtips, for a total wingspan of 45", which increases the wing area to 303 in², a 21% gain. With a flying weight of just 20 oz., that works out to a final wing loading of a mere 9.5 oz./ft². That's still a bit higher than the spec loading, but it results in a much more docile airplane. It was definitely worth the effort. By comparison, my 85% Airtronics Aquila sailplane has a wing loading of 6.2 oz/ft². It's a real floater, as you might expect.

Posted July 1, 2024