Flying Pacmans and Other Drenalyns
Many years ago, my brother and I built a Speed-400 powered "Flying PacMan". It was essentially a piece of 3mm Depron shaped like those nasty ghosts in the PacMan video game. The sheet was glued on a foam fuselage.
Many people have had similar ideas over the years. One of the most popular designs has come to be known as the "Drenalyn", popularized by the Aero Modelist Club Creusotin, in Le Creusot, France (blueprint of Philippe Jambon's Drenalyn V3D is available in PDF (24KB) and in DjVu (11KB)
My dad and I built several more flying PacMans and Drenalyns since then.
This is one of the most fun-to-fly plane I have ever built (as of Spring 2002)!
The A.D.V.E.R.S.E., which is even more fun, is a derivative of this plane designed for vertical takeoff right from the start.
constructionIt's pretty much a scaled down version of the standard Drenalyn (504mm diameter instead of 610mm for the original Drenalyn, see links to Philippe Jambon's blueprints above). The wing is a single 3mm Depron sheet with a single carbon rod stiffener near the back. The carbon rod also serves to hold to thin music wire skids. The fuse is a chunk of pink foam (like the one you find in the US at Home Depot for insulation). The battery also comes from Home Depot: it is made from eight 700 mAh NiMh cells sold at Home Depot. For our Depron-starved American friends, I suppose the wing could also be build from Zepron, but it may have to be stiffened with another rod near the center of gravity.
in flightThis beast has amazing flight characteristics. The range of possible flight speeds is nothing short of hallucinating. You can fly quite fast in horizontal flight, and slowly transition to hovering flight with the plane hanging vertically by the prop. Dosing the power in this flight configuration is the trickiest part, but with enough practice, you can hover for minutes at a time. The best part is, if you get in trouble, just apply full power, push up the elevator stick a little, and the thing just climbs vertically. If you don't push up on the stick, you will experience the most common failure mode: a back flip. Even if you happen to do a back flip at low altitude, the structural damage will be non-existent to minimal (but remember to bring spare props to the field!).
And now for something completely different. This micro Drenalyn is a gentle-flying indoor animal. It is built from 2 thin carbon rods and one carbon tube, with little pieces of Depron and a light iron-on covering material.
This baby is very light and slow, ideal for indoor flying. With a 7-cell 150mAh battery or an 8-cell 300mAh it's just a tad underpowered or overweight (it flies fine, but there is no big reserve of power). An 8-cell 150mAh NiMh, or even a 7-cell 70mAh NiMh would be ideal, but I haven't tried that yet.
Like its semi-namesake the Flying Dutchman, the Flying PacMan is a ghost. Well, it's shaped like a ghost anyway. It is designed to look like the nasty little ghosts in the video game PacMan.
The wing is (not surprisingly) a 3mm sheet of depron glued to a yellow foam fuselage. It was originally powered by a Speed-280 with a 4:1 JH gearbox and a 3 blade prop (slowflyer drive stock number JH28043 from Hobby Lobby), with 7 to 8 cell batteries anywhere between 300 and 700mAh NiMh.
It flies very gently and is an ideal platform to teach kids to fly model airplanes.
The plane is now powered by a Nippy 280 brushless outrunner/LRK motor (also obtainable from Hobby Lobby) with a GWS 9047 orange prop. The battery is an 8-cell 700mAh NiMH, but 2-cell 1200 mAh LiPo high dischage LiPo would be even better. This new motorization gives it a lot more power for steep climbs.