If you have 700 hours to spare and can shim a rotor assembly to within .001 of an inch, here's a hobby for you.
- By James R. Chiles
- Photographs by Joe Loxterkamp
- Air & Space magazine, August 2010
(Page 3 of 4)
Finishing a helicopter both completes a challenge and begins another. Let’s assume that the new two-seater is rigged and balanced perfectly. Assume also that a certified flight instructor is on hand. Even so, the first days of practice are likely to be frustrating—even scary—because it takes time to develop the reflexes and multi-tasking skills unique to helicopter piloting. Once skids depart ground, pilots must make constant, small corrections on the controls without delay. Early kit-built rotorcraft had such a high crash rate that an FAA inspector in a July 1970 Popular Science article called them “the most dangerous type of experimental aircraft in use today,” and warned that 95 percent of the crashes happen at low speeds near the ground. It was a sobering change in tone from that found in earlier magazine articles. One reason for trouble among novices is the phenomenon called dynamic rollover. If a helicopter pivots around a landing gear during liftoff or one landing gear makes inadvertent contact with the ground while sliding sideways, the thrust of the main rotor will flip the machine on its side, requiring thousands of dollars in repairs.
The major brands of kit helicopters share the layout of Igor Sikorsky’s classic VS-300 prototype of 1941, which combined a single main rotor for lift with a small, vertically mounted rotor on a tailboom to offset the main rotor’s torque. Flight controls on kit-built helicopters mimic those on their production counterparts. Two “anti-torque” foot pedals control the pitch of the tail rotor and point the nose left or right; a collective lever connects to the main rotor and urges the machine up or down; and a joystick at knee level called a cyclic adjusts the main rotor to tilt the helicopter so it flutters off in the desired direction.
Orv Neisingh is an independent Missouri-based expert who has been training pilots on RotorWay helicopters for 10 years, and now holds an airframe-and-powerplant license that allows him to sign off on repair work during his field visits. That elevates him to one of an elite corps of consultants. Liability concerns, the small size of the kit-copter market, and the inclination among builders to perform their own repairs keep the number of licensed mechanics who deal with kit-built helicopters low. Neisingh’s service comes with a wise skepticism. Before scheduling work where he would fly another’s kit helicopter for training or testing, he requires the new customer to fill out a long and sobering checklist.
RotorWay customers can also go straight to the factory. RotorWay runs its flight school out of Stellar Airpark in Chandler, Arizona, in three sets, or phases, of classes. Each phase takes up to a week. Phase 1 is mainly for hover practice, which alternates with school on documentation, maintenance, and rigging. According to Robin Wactler, director of the flight school, the best time to come for Phase 1 training is near the end of construction, but before the main rotor is complete.
Nearing the end of their build, Helicycle owners are required to spend a week with an Eagle R&D representative like Doug Schwochert of Burlington, Wisconsin. Schwochert’s house call comes at an extra charge but it isn’t optional, since he brings a crucial pair of main-rotor bearings available only from the factory. (After B.J. Schramm liquidated his interest in RotorWay and founded Eagle R&D, it was Schwochert who convinced him that a turbine instead of a piston engine should be the Helicycle’s standard powerplant.) Schwochert inspects each part before lighting off the turbine, followed by a series of adjustments before test flights begin.
A refurbished Solar T62 gas turbine once used in generators is the standard engine, accounting for a quarter of the kit’s $39,800 price. Its power section spins at 62,000 rpm, more than 1,000 times a second. Gearboxes bring this down by a factor of 20 to suit the tail rotor, and still further for the main rotor. Though the Solar is rated for 160 shaft horsepower, Eagle has cut fuel flow, holding it to 90 shaft hp for longer life.
IT’S JUST AFTER LUNCH in the RotorWay school hangar, and the talk is of grease: the red variety, in a big shiny grease gun, and where to point it. A RotorWay 162F Executive (superseded by the A600 Talon in 2007) has grease points under the main rotor and around the tail rotor drives. Explains Robert Preston, the company’s factory instructor pilot, owners will be wielding the gun every 25 hours of routine operation, and will be checking air and fuel filters, changing oil, and tightening the chain drive and the three rubber belts that drive the tail rotor.
When explaining how to tighten bolts, Preston advises student Don Pool: “Remember, this is an aluminum block and steel wins every time, so don’t apply more torque on the bolts than necessary—no monkey strength allowed!” With time out for flight training, Preston spends the week shouldering through a long list of RotorWay-specific techniques.