RE: Pusher AP plane build thread
I don't know. I mounted my engine inverted to keep the firewall small while getting the prop shaft as high up as I could. I don't have the engine cowled in at all. I think there is more than enough airflow to run this way. The engine isn't in the prop wash but at an idle on the ground and getting run up for take off gets the plane in motion. A tightly cowled engine in a tractor configuration is at greater risk. I think it will be OK that way. It will also allow the carb to stay lower down the firewall so it's closer to the fuel pickup level in the tank. One can always put an engine mount with longer rails on to push the engine and muffler farther away from the fire wall for clearance. If Skycam41 has adequate prop clearance for his known runways it may not be an issue. I've seen a lot of planes with props close to the ground that aren't set up in these twin tail boom pushers like ours. It's common to see grass stains and nicks from rocks on the props so I don't want to sound too paranoid about the clearance. Low wing tail draggers bust props commonly on bad landings. I think I just got jumpy because I was flying off gravel with Zinger 18 inch wooden pusher props. A rock in the right place and I was out a 25.00 prop just like that. That 2 cid gas Fuji I’m using really vacuums loose debris on a take off run. It moves one heckuva lot of air.
I don’t see any reason he wouldn’t want to shift the thrust line upward above the aircraft centerline. Randall1959 does that to great extent by putting the motors and engines on his planes up high on pylons etc. I don’t like to move too far away like that just because of induced drag in that style. I’m not suggesting that’s a bad thing mind you. In a slow flying stable AP plane that’s a manageable quality. My application just works better with faster flight and more efficient travel through air. I conserve fuel that way too.
Dan