predator mods
05-04-2002 | 03:34 AM
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From: ND
predator mods
Randy, here's the changes that Darrol Cady reccommended in the Feb. NMPRA newsletter:
1. cut a 2.25x2.25x1/8" aircraft plywood plate. Epoxy it to the front of the firewall before you start drilling any mounting holes. This will disperse any shock of a hard landing to the fuselage side and the top and bottom. It will help keep the firewall in cace of a bump.
2. Triangulate the wing to the fuse and tap the mounting holes with 1/4-20 nylon bolts. The metric bolts will be impossible to replace if you misplace them.
3. Replace the hardwood wing hold down plate with plywood of the same thickness and make a fillet of epoxy and micro-balloons around bottom all of the wing hold downs and the landing gear block.
4. Drill and pin with toothpicks all of the wing hold downs, landing gear blocks and the firewall.
Changes that are nice and will give better performance:
1. Cut the aileron torque rods out and replace them with 4-40 threaded rod. This must be done before the ailerons are glued in place.
2. raise the stab about 3/8" and put the elevator horns inside the fuse. Lots of work, and I am not sure the effort is worth the performance gain.
3. Replace the push rods with 1/8 carbon push rods.
I think everyone interested in pylon racing should join the NMPRA to get this type pf information on a regular basis, Its a great voice for ur racers also! Bawana.
1. cut a 2.25x2.25x1/8" aircraft plywood plate. Epoxy it to the front of the firewall before you start drilling any mounting holes. This will disperse any shock of a hard landing to the fuselage side and the top and bottom. It will help keep the firewall in cace of a bump.
2. Triangulate the wing to the fuse and tap the mounting holes with 1/4-20 nylon bolts. The metric bolts will be impossible to replace if you misplace them.
3. Replace the hardwood wing hold down plate with plywood of the same thickness and make a fillet of epoxy and micro-balloons around bottom all of the wing hold downs and the landing gear block.
4. Drill and pin with toothpicks all of the wing hold downs, landing gear blocks and the firewall.
Changes that are nice and will give better performance:
1. Cut the aileron torque rods out and replace them with 4-40 threaded rod. This must be done before the ailerons are glued in place.
2. raise the stab about 3/8" and put the elevator horns inside the fuse. Lots of work, and I am not sure the effort is worth the performance gain.
3. Replace the push rods with 1/8 carbon push rods.
I think everyone interested in pylon racing should join the NMPRA to get this type pf information on a regular basis, Its a great voice for ur racers also! Bawana.
05-04-2002 | 06:27 AM
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From: Tempe, AZ
Predator Firewall Reinforcement
Bawana and to ALL,
If you want neat look and a Very Strong Firewall, do the opposite of Darrol's recommendation. Instead of adding plywood to the outside, in front of the firewall, it's much better and stronger by laminating Carbon Fiber on the inside of the Firewall and sandwich a 1/4" plywood in between for the blind nuts to dig into. This not only cleaner, but it's probably 100 times stronger than it needs to be. I can attest to it because I had radio interference at Speedworld and the plane drop out of the sky straight down (nose first) and it didn't do anything to it except the wing bolts broke. The whole plane was in one piece standing straight up with it nose digging into the dirt (except a slight dent in the left leading edge area) and I went to race at the Basin the weekend after that. I was amazed how strong it is and I couldn't believe it with my own naked eyes. Just a note and something to think about as an alternative to Firewall reinforcement.
Sam S.
If you want neat look and a Very Strong Firewall, do the opposite of Darrol's recommendation. Instead of adding plywood to the outside, in front of the firewall, it's much better and stronger by laminating Carbon Fiber on the inside of the Firewall and sandwich a 1/4" plywood in between for the blind nuts to dig into. This not only cleaner, but it's probably 100 times stronger than it needs to be. I can attest to it because I had radio interference at Speedworld and the plane drop out of the sky straight down (nose first) and it didn't do anything to it except the wing bolts broke. The whole plane was in one piece standing straight up with it nose digging into the dirt (except a slight dent in the left leading edge area) and I went to race at the Basin the weekend after that. I was amazed how strong it is and I couldn't believe it with my own naked eyes. Just a note and something to think about as an alternative to Firewall reinforcement.
Sam S.
