ORIGINAL: rc34074
i would get a bisson muffler- i use the pitts style mufflers with the g90 mounted at 9 oclock and the tube a 6 oclock or so. you will want to crimp the outlet tubes of the muffler down a little so they look like an oval horse race track. this adds a little more back pressure and the g90 will run just a bit more consistently at different throttle settings. but i ran my g90s for years without doing this so its not a big thing. anyway the g90 likes the apc 14-6 prop, at least i like the way it flies my warbirds.
i would also recommend usng air baffles to direct the air over the engine piston area mainly. this will reduce the amount of cowl you will need to remove for cooling the g90. anothe thing you might consider is leaving some increased area between the cowl and the fuse behind the head.
not to confuse things but how much will the corsair weigh when its done? if its 10 lb or more then the g90 will be ok but not as strong as i like. the best alternative then is the st 2300, which is a 1.4 cubic inch engine. they are going for very good prices.
one more thing- you didn't ask about retracts but for this plane i would highly recommend you your retracts from sierra. the robarts are not real strong, and for only a few dollars more the sierra AS for the cow,l retracts are far superior. they c ome with the oleos included and look very strong. but as i don't have any corsairs you should do some searches here in the warbirds forum and you will see lots of threads about rotating retracts and comments from guys who have struggled with their rotating retracts.nn
good luck-
ed
HI. Thanks for your input .Seems that Bisson seems to be the popular choice at this point .I think they are fellow Canucks too aren`t they? That APC prop you`re suggesting is it a 4 blade job? If it is and works as good as you say, it would be correct for the F4u-5 version I`m making. About air flow through the cowl Ihave purchased the TOP FLITE. dummy engine and fabricted the 1/8 th lite plywood radial engine support Once I have an exhaust system in my hands, I plan on fabricating a very lite gauge aluminum shroud that will attatch to the lite ply dummy support around the air inlet at the front of the cowl where it is cut open for the cylinder,head and carb.As far as Outlet air the authentic bird had 4 ``pockets``that its exhaust tips exited .These will be be left open with fake exhaust tips installed on my rendition. Also I am going to engineer a opperating cowl flap system. I have a couple of good ideas but the lay-out needs to be planed around a complete and ,permenent ,opperating, engine /exhaust combination. SO,I think , with, the duct, the air outlet thru the 4 pockets, 1 which i intend to exhaust the SUPER T thru,plus cowl flaps ,should keep it beautifully cool. What do you think?? Idon`t want to cut cowl at all, if I can avoid it. Pertaining to weight,I`m not totally certain yet.I~m pretty sure it will be slightly over the listed (on box) weight .I`ve got the robart air retract system inc.struts,and tires(diamond tread with correct apearence rim, also ,dual ailerons dual wing flaps all shooting the weight higher. The wing and fuse are glassed also bringing things up^^^there .AS far as all the Robart parts we seem to be somewhat limited to what hobby supplier can or will get in around these here parts of the Continent. THANKS for the reply. TAlk to you again ,.Any ideas,suggestions will definately be considered FLY for now!! DAVE.B.