Wingspan: 24 in
Length: 18 in
Wing area: 95 sq in
AUW: 3 oz
Wing loading: 4.4 oz/sq ft
Power loading: 55 W/lb

Stevens AeroModel DiddleBug


The DiddleBug is an ultra-lightweight 3-channel indoor/backyard flyer from Stevens AeroModel. With its wing pylon, elliptical wing, swayback fuselage, wheel pants, and fake glow engine cylinder head, it has a classic look, reminiscent of the freeflight models of yesteryear.


The DiddleBug is tiny; the kit consists of three 4"×24" sheets of 1/16" balsa. To the right is a picture of the entire kit (except for a couple of small pieces of wire used for the landing gear and pushrods), with a cell phone included for scale.

The DiddleBug took about six hours to build, of which two hours were spent shoehorning the electronics into the fuselage. The flight gear is:

The all-up weight of the completed model is 83 g, or only 2.93 oz. (Adding LEDs (see below) brought the AUW to exactly 3.0 oz.) As-built wing loading is 4.6 oz/sq ft.

Flight video

The DiddleBug's successful maiden flight was in light snow on 2007-12-05. The airplane flies great—it is nimble and surprisingly fast for its weight. It climbs quickly under full power, has a decent glide (considering its high-drag undercambered airfoil and open-bottom fuselage), and turns quickly, even with the rudder throw set as low as possible. The elevator is small and has very little authority; altitude must be controlled with throttle. To the right is a link to a flight video.

Landings on rough surfaces (such as asphalt) are a challenge; the springy gear and small wheels allow the front edges of the wheel pants to dig in, causing the model to flip over onto its back as soon as it touches down. One solution would be to remove the wheel pants and replace the wheels with lightweight 1" GWS wheels, but I'm reluctant to do this because the wheel pants are a major part of the model's charm.

Some pictures:

DiddleBug DiddleBug DiddleBug DiddleBug DiddleBug


The DiddleBug is very light, and flies best in windless conditions, which usually occur at dusk. Thus, the DiddleBug is a good candidate for LED lighting. After a few weeks of flying, I installed two high-intensity (approx 2500 mCd) LEDs, one red and one blue, in the top of the turtledeck, illuminating the pylon and the underside of the wing. With these lights, it is easy to see the orientation of the airplane in the dark.

w/LEDs w/LEDs w/LEDs