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bmears9413@aol.com wrote:
I understand what Chris is thinking. I dont want to get my motor setup dialed in with a prop spinnin' around me. Wonder if there would be another way to load the engine without a prop while tuning? maybe like a temporary generator or alternator under a hard load? Anybody got any ideas?
Bob Mears
Supermarine Spitfire
two words:
test club
It doesn't have to look like a prop. Cut a couple of 3 ft diameter plywood disks & sandwich 6 2x4's between them in a radial pattern. (Rip the 2x4's to end up with the same total thickness as your future prop.) Drill at the 2x4 locations for the prop bolts. Do a rough static balance.
Obviously, you don't want to spin this affair at full engine power, but it will provide at least some air load.
If you back into the disk, hopefully it will just rip your shirt and/or throw you across the room instead of taking off an appendage.
You'd be really surprised at what a/c engine companies have used for test clubs. My neighbor collects old aviation stuff. He's got a test club that has the blades pitched in opposite directions. Ponder the loads on that crankshaft when they spun up the engine.
Charlie
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