Larry S
Posts: 443
Joined: 3/3/2004
From: Manteno,
IL, USA
Status: offline
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Before I post the changes I made, you might want to think about this in trying to decide if the modifications are worth the time and trouble. Late last year, I was fooling around, doing touch and goes, etc when on one take off, it snapped in, my fault. The plane went in nose first breaking a nylon prop and knocked off the wing. Damage to plane: wing, none. Fuselage including cowl, scratched all to hell, simple fix with airbrush. The skin had small cracks, more like fractures and I fill them in with micro ballons. The paint I mixed looked close but went on darker then I wanted but after looking the bird over, it looks cool. It looks weathered like a war bird should. All formers including the firewall held up. No wood parts were broke. IF I hadn't done the extra work, I would be buying a new plane. So here goes.
Changes I did to CMP 50 Corsair:
Coarse sand complete inside of cowl. Mount dummy engine on 1/16 ply and using heavy fiberglass material, epoxy dummy engine in cowl. I found it was easier to insert dummy engine exactly where I wanted it then applying three or four drops of thigh CA and use an accelerator to hold it in place until the epoxy sets. I used the fiberglass material and epoxy on the joint between the dummy engine and sides of cowl and turned the cowl on it’s nose to let any excess epoxy run into the nose of the cowl. Use strips of cloth and overlap each one. Epoxy that ran into front ( nose ) will strengthen that area. Noseovers won’t break the cowl as easily. After that sets, use 3/4 glass cloth and do the complete inside of the cowl being careful not to get any epoxy on the painted surface. Now you have a strong cowl. Where ever your screws will go through to hold the cowl add one more one inch squares of 3/4 glass cloth to build up that area. I also first screwed the ply ring onto the fuse that holds the cowling. After I was satisfied on the location, I took it off, added epoxy on the inside of the ring and screwed it back on. Forget about the added extra weight at this time.
I made my own mounts from a better grade of ply for the landing gears. I had first installed RhomAir retracts but they gave me problems so I decide to go with a fixed gear. I didn’t trust the ply I got with the kit, that is why I used my own and I epoxied everything in.
Inside of the plane: sand as best as you can and add epoxy to all the formers. I even bent an epoxy brush backwards to get to the opposite side of the formers. Between the formers and skin, that is a weak area that will come loose over time. Not anymore.
Firewall: Add epoxy and cloth between the firewall and fuselage where ever you can get it. That is one area that seems to never be as strong as it should be from an ARF. One important thing I found with my Corsair, plans show 2 degrees down and 2 degrees right thrust. I found that my Corsair had the right thrust built in but no down thrust, so I made a shim to put behind the motor mount to off set that thrust. Don’t fly it until you have both right and down thrust.
Again using a bent epoxy brush, fuel proof all wood inside from the servo tray to the fire wall of fuselage. That also helps keep the glue they used from coming loose. Lot’s of weight, but useable weight, you’ll see.
Canopy: I screwed mine on but first epoxied blocks of hard wood to the inside of fuse at the points where the screws would go through.
Control surfaces: I use only epoxy, no CA on hinge areas. I’m not sold on CA for that.
Servos: mount them as far forward as possible.
Engine: I first tried an OS 46 FX and it was marginal. If our grass field had just been mowed, no problems but if the grass was high, then the 46 would need a lot of runway to lift the plane off. I ended up going with an OS 61. That engine does the job, gets the plane rolling at a good speed before lift off then I just throttle back to where I like to fly. Make sure you have your airspeed up before lift off and when it comes time to lift the plane off, it will probably go up by itself if trims are set very good. But if the trims are not set the first time, which they probably won’t be, don’t force the plane up. After the plane is rolling, EASE back on the elevator till the planes lifts then hold it there until the plane reaches the altitude you want. Gently let it climb, no hard turns. Once the plane reaches speed, then you can do what you want, you’ll have altitude to work with. One thing, none of my Corsairs will do is a stalled, snap roll. I have crashed more Corsairs then you would want to know and every time, the same way.
CG: On the CMP Corsair, the shown CG is close, but no cigar. You can fly it that way and I did on my first flights but you’ll have your hands full. I used a CG of exactly 3 inches from the leading edge, spaced 15 inches apart using a Great Planes balance machine. This is a little less then the 80mm to 85mm shown in the plans. That means the plane has to be a little more nose heavy to balance and remember all that epoxy you added in the cowl, it now has become your friend. I still had to add some lead weight, but not as much if I hadn’t reinforced the cowling.
Guns: Airbrush out the decal guns on the plane and install 1/8 brass tubes where the guns should be, outside the gull.
Remember, these are changes I made based on my having two of these planes, one of which is no longer with me.
< Message edited by Larry S -- 1/16/2007 3:23:41 PM >
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All Forums >> RC Airplanes >> RC Warbirds and Warplanes >> RE: New CMP 50-sized Corsair 
RE: New CMP 50-sized Corsair - 
Learned something new concerning the white lines interesting... Now if I may, what is with the arrows.... One on the rudder would seem to say "this side up" and the one on the wing "fly in this direction" ?....
