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Old 04-12-2009, 02:43 PM
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Bob Pastorello
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Default RE: Newbie to Gas General Information

Thank you! Hope it is helpful. Continuing...

24. Gassers vibrate. Period. Firewalls must be STRONG, and pinning around their circumference with wood dowels or epoxy/nails is a good practice. Pulling the engine box off an ARF is easier to do than you think.

25. Your engine will probably require "standoffs". Measure your ARF from intended prop spinner backplate to firewall. Deduct the overall "mounting length" of your engine, plus 1/8". Whatever is left is the "standoff". You can buy metal ones, or make your own out of hardwood dowels, whatever. BUT - they have to mount real solid-like. Find sources of long #10-32 hex head bolts, split washers, flat washers, fender washers and nylon-insert Locking nuts. USE them. It is a BAD plan to have an engine come loose.

26. Allow "exit area". You cannot avoid it. You either make holes to let LOTS of air out of your cowling/nose, or you cook your engine. Period. If you are able to do it, direct air by dams or ducting directly over the fins of the engine, THEN to the "big exit area".
If you hover, or do strenuous 3D....skip this step and you'll cook the motor, probably seizing it up at a low-altitude hover by overheating, thereby crashing your airplane ALSO.

27. Props - the most important accessory for your engine. Bad props give sucky performance, break easily, or disappoint you in their performance. Any good prop of the manufacturers rated size will make you a happy gasser.

27a. Prop Balancing - probably an oft-ignored and vitally-important "thing" for gasser guys. A good balancer is essential. A bad balancer is a waste of money. I prefer the Dubro Spin balancer....very sensitive. Blades are balanced by lightly spraying the back of the blade with clear spray lacquer- lightly...until blades balance. If blades are balanced, but moves anyway, check the hub. Put the prop on the balancer with blade vertical. Release blade. Watch top blade....if it falls LEFT (as you're looking at it) then the RIGHT hub needs weight, and vice versa. Weight on the hub is the curly velcro, ca'd in place, a few drops of thick ca, then kicker. Recheck balance. Keep at it until the prop remains motionless wherever you position it on the balancer. THAT is perfect balance. Takes about a half hour on a 22", more on bigger. DO IT.
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