CMPro Super Chipmunk Repair questions??
02-28-2007, 10:20 PM
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CMPro Super Chipmunk Repair questions??
I have recently been given a CMPro Super Chip that is in need of some TLC. This plane had a Super Tigre .61 in it and the stock muffler (which is a huge can). The guy chopped into the firewall in order to make the muffler fit. He also modded the plane to be dual aileron servos instead of a single servo set up. He flew it once and did not have the engine tuned right and it stalled on him. It landed in a cultivated field and bent the landing gear and cracked the fiberglass right by the firewall. I am going to recover the bottom of the wing as you can see he patched it and did a poor job. But i have never worked with fiberglass before and also would like to replace the firewall or at the very least the piece he hacked out for the muffler. Can anyone give me some tips on how to patch the broken fiberglass and deal with the firewall? thanks in advance. As you can see in the one photo i have a little helper that likes to play with my RC stuff. Hopefully a future flyer!!!
Flyboy76
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03-01-2007, 01:11 AM
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RE: CMPro Super Chipmunk Repair questions??
Some people should never have access to a chainsaw !!
Mine had excessive slop in the aileron torque rod guide slot, so I did the twin servo trick, but not big enough for 1/4 scale servos though. Much better aileron throw that way. Thin Ca will stiffen up the smaller fractured areas and auto Spot-n-glaze thick primer putty will fill the missing gell coat and then repaint. Most auto parts stores will carry it if you don't have a local auto paint store up there.
After plugging the firewall with 1/4" plywood, take a 2 ltr pop bottle and cut it about 1/2" oversize to the opening. It's already curved so should be easy to fit inside. Rough up the outside with 60 grit sandpaper then Ca in place to hold it till you can start laying up fiberglass cloth to fill in the cut area. A little overlap inside will help bond to the good part. Not a perfect match, but at least it's on the underside. Mine has an inverted ST 61 with only a muffler hole coming out on the drivers side. It's a great flying plane and you'll be pleased once you've finished the work. OR, a new one from Nitro is only $119.00
Mine had excessive slop in the aileron torque rod guide slot, so I did the twin servo trick, but not big enough for 1/4 scale servos though. Much better aileron throw that way. Thin Ca will stiffen up the smaller fractured areas and auto Spot-n-glaze thick primer putty will fill the missing gell coat and then repaint. Most auto parts stores will carry it if you don't have a local auto paint store up there.
After plugging the firewall with 1/4" plywood, take a 2 ltr pop bottle and cut it about 1/2" oversize to the opening. It's already curved so should be easy to fit inside. Rough up the outside with 60 grit sandpaper then Ca in place to hold it till you can start laying up fiberglass cloth to fill in the cut area. A little overlap inside will help bond to the good part. Not a perfect match, but at least it's on the underside. Mine has an inverted ST 61 with only a muffler hole coming out on the drivers side. It's a great flying plane and you'll be pleased once you've finished the work. OR, a new one from Nitro is only $119.00
03-01-2007, 01:15 AM
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RE: CMPro Super Chipmunk Repair questions??
Forgot to pick reply on your note in order to post a photo.
Be sure to have the CL of the gear axle about 1" in front of the wing leading edge to prevent nose over on takeoff and landing.
Be sure to have the CL of the gear axle about 1" in front of the wing leading edge to prevent nose over on takeoff and landing.
03-01-2007, 09:17 AM
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RE: CMPro Super Chipmunk Repair questions??
Ya i was initially thinking about buying a new one but this one was given to me and it is a chance to work on my repair skills and learn about fiberglass at the same time. And if something goes very wrong and i wreck it i am out nothing. Then i can spend the 119 and on top of that i have a spare wing. Also is yours the 63" wingspan or the 57". I need a new cowl and mine is the 63". Are you suggesting i take out the chopped firewall and install a new one?
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03-01-2007, 11:00 AM
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RE: CMPro Super Chipmunk Repair questions??
Mine is the 63" also from Kondor/CMP/Nitro/whomever.
Nah, just cut a plug the shape of the firewall cutout and epoxy in place then cover in glass.
A Chipmunk is second only to the Cap 21 as being snap happy. Watch the slow speed turns. I always raise both ailerons up about 3/16" to give washout on these and warbirds. This really slows down the tendency to snap.
Nah, just cut a plug the shape of the firewall cutout and epoxy in place then cover in glass.
A Chipmunk is second only to the Cap 21 as being snap happy. Watch the slow speed turns. I always raise both ailerons up about 3/16" to give washout on these and warbirds. This really slows down the tendency to snap.
03-01-2007, 06:46 PM
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RE: CMPro Super Chipmunk Repair questions??
ORIGINAL: HuskerBoy
Mine is the 63" also from Kondor/CMP/Nitro/whomever.
Nah, just cut a plug the shape of the firewall cutout and epoxy in place then cover in glass.
A Chipmunk is second only to the Cap 21 as being snap happy. Watch the slow speed turns. I always raise both ailerons up about 3/16" to give washout on these and warbirds. This really slows down the tendency to snap.
Mine is the 63" also from Kondor/CMP/Nitro/whomever.
Nah, just cut a plug the shape of the firewall cutout and epoxy in place then cover in glass.
A Chipmunk is second only to the Cap 21 as being snap happy. Watch the slow speed turns. I always raise both ailerons up about 3/16" to give washout on these and warbirds. This really slows down the tendency to snap.
03-01-2007, 10:16 PM
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RE: CMPro Super Chipmunk Repair questions??
Norm,
I've found raising both ailerons while in neutral tames this type plane down till you get use to it. The axial rolls will be a little slower, but I'd rather it be more stable on approach. This not a cure all as I almost went into a death spiral while playing tag with a couple of turkey buzzards. I got too slow and tight in a turn trying to match their moves. The gear forward is important too if you want to save your prop and cowl.
I've found raising both ailerons while in neutral tames this type plane down till you get use to it. The axial rolls will be a little slower, but I'd rather it be more stable on approach. This not a cure all as I almost went into a death spiral while playing tag with a couple of turkey buzzards. I got too slow and tight in a turn trying to match their moves. The gear forward is important too if you want to save your prop and cowl.
