. . . aren't planes supposed to fly from point "A" to point "B" instead of getting towed?
Ordinarily, yes, but this plane has been hangered for 20 years. The last owner was planning some modifications in 1992-93 and then bought a Mooney and left the plane alone. He died in 2007 and it became available the first week in October. I drove up and after a through examination, bought it.
Now this particular plane had a 1984-86 vintage, 1835 cc engine and sad experience revealed two serious problems:
- prop flange and crank shaft fractures - there are two cases where the props separated, at least one in flight, and a crankshaft fracture in flight.
- aluminum flywheel - aluminum is subject to work weakening and fracture. It isn't if it will fail but when.
It is my intention to have a new engine built using the most advanced techniques we know of today:
- tapered prop flange mount - this includes a deeper prop flange nut to help minimize stress concentration around the flange. The tapered mount instead of the slip-and-key mount prevents a high impact, vibration mode that would contribute to flange fracture.
- steel flywheel - better material that recovers instead of stretching as aluminum does
- electric only ignition with dual 12V supply - electric ignitions have better advance and retard capabilities and a significantly hotter spark. Aircraft engines often run rich leading to carbon deposits on spark plugs that magnetos have difficultly dealing with. Electronic ignition gives a much hotter spark and dual, 12V supplies reduce risk of the most likely failure mechanism occurring.
- four-in-one exhaust and O{2} sensor - in addition to the exhaust temperature gauge, this provides a finer mixture control. It should be a little quieter and give the option of adding a 'stinger' to direct exhaust pulses away from the cabin.
We've also learned several lessons about this airframe that can improve safety:
- vortex generators on canard - this improves handling in rain and from bug splatters. Vortex generators are often found on airliners on the outboard segments to improve aileron authority at low speeds and high angles of attack.
- water drains - we found over a gallon of rain water in the fuselage. We dumped most of it but some still remains so I'll add three drains: tail, behind main bulkhead, and in front of the canard, drag bulkhead. Water sloshing about the fuselage is bad news in flight and not a good idea for the electronics, steel cables and steel control linkages.
- move rudder pedals forward - mount on the canard lift bulkhead to give an extra 8" of leg room.
- hinged canopy or front inspection plate - there is no easy access to the area behind the instrument panel and the rudder and control area. A hinged canopy provides access and provides more space for the pilot and passenger to get in and out but leads to water sealing issues. An inspection plate is easier to seal and would have a lower weight impact. This is not decided, yet.
- steel landing gear - provides more flex to make landings less risky but I'm thinking about other options too.
- nut plate on the canard lift and drag fittings - so bolts and tools won't fall in difficult to reach areas.
- cargo net over the wing area.
- pockets in the seat back bulkhead for maps and flashlight.
In 20 years, aircraft avionics has gone through a generational change:
- mode-C transponder - this foam and fiberglass airplane is nearly invisible to radar so an encoding, transponder makes sense.
- GPS - map, backup altimeter, performance data recording, backup ground speed.
- small, lighter nav-com - provides legacy VOR navigation and communications.
- LEDs - high intensity LEDs are in navigation, cabin, and even landing lights.
- alternator improvements - more reliable regulators and battery options.
Yes, I would have preferred having the plane 'flyable' but there are good reasons for rebuilding including inspecting every part and adding the safety and performance enhancement we've learned about in the 20 years it was in hangers. There is no reason to repeat what others have already pioneered. <grins>
Bob Wilson
- ZVW30
