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Tri-Motor Homebuilt: Laudable Effort, but Is It an Airplane

By Pat Panzera, Editor, Experimenter

China Tri-Motor

March 3, 2011Auto mechanic Ding Shilu of China’s Liaoning Province created some significant ripples on the Internet this week when photos of his home-designed and -built tri-motor aircraft were posted in several locations. The contraption is reportedly made of recycled materials including three motorbike engines and plastic cloth and cost almost $400. Total weight is reported at 130 kilograms (about 287 pounds). The series of photos includes an apparent taxi test conducted on a frozen reservoir in Shenyang, Liaoning. Pat Panzera, editor of Experimenter, EAA’s homebuilding e-newsletter, saw the photos and had these thoughts about Ding’s invention, which Pat hesitates to label an airplane.

While credit and respect has to be given to Ding for undertaking such an audacious task of designing, building, and testing, those of us who are fortunate enough to have educational resources like the EAA are likely cringing in horror - just as we did with a similar undertaking by Gabriel Nderitu, the Kenyan homebuilder we reported on back in October 2010. Like Ding, Gabriel built an “airplane” powered by passion more than anything else. But unlike Gabriel, Ding’s vehicle at least got one wheel off the ground.

Again, I can’t begin to express my respect for these types of undertakings and the people behind them. The sacrifice, as unimaginable as it is, is surely an outward sign of the unquenchable desire for flight. While those of us who fully grasp the obsession to “slip the surly bonds” will applaud the effort, we still can’t help but to recognize that the effort is for naught. If in fact Ding’s project ever climbs above ground effect, it probably won’t end well and although the reports don’t specifically state it, we can assume that Ding doesn’t have any formal flight training.

Reports of the 130-kilogram (287-pound) aircraft state that the builder has invested roughly 2,600 yuan, which depending on which day we check is roughly $395 USD. That’s just over the annual income for many people in rural China.

Observations based on the information at hand and the photos: Power comes from three unshrouded motorcycle engines and (thankfully) seats only one occupant. In true EAA homebuilt spirit, it was crafted from recycled and previously used materials, including the rigid tricycle gear’s wheels - which appear to have been borrowed from a motor scooter.

The short wingspan is reportedly because of “airstrip” (narrow dirt road) restrictions; power lines border each edge. The sharp leading edge of the flat-bottomed airfoil (covered in “plastic cloth”) suggests that - should it ever actually take flight - the stall will be without warning and fairly unforgiving. The huge, rectangular flat-slabbed ailerons are hinged off the trailing edge and in plane with the equally rudimentary horizontal stabilizer and elevator. Being so short, coupled with the aileron trailing edges being only inches in front of the horizontal stabilizer leading edge, downwash from the wing will certainly affect the elevator. One would think that this aircraft would be very pitch sensitive.

Each of the three engines turn crudely constructed wood propellers driven by a single v-belted propeller speed reduction unit- a fancy term for a set of pulleys, in this case - that reduce the engine RPM to a more propeller-friendly speed. It appears from the photos that the engine drives the belt with the centrifugal clutch leftover from the motorbike. All three props turn in the same direction and no two blades look exactly alike.

Although we certainly wish Ding all the best, it would have been nice if an EAAer – a Technical Counselor - was available to mentor and guide him. With the money, time, and effort he’s already expended, it’s entirely possible some properly focused direction might have resulted in an aircraft he could fly safely

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