Viper 500 ARF (GPMA1265/1266)
Some engines have backplate bolts that are not long enough to properly mount the engine to the engine mount. Please see the addendum below for further information.
The metric hex head bolts included with the Viper ARF work with the OS engines but may not work with some other brands of engines.
The rule of thumb is the bolt must thread into the crankcase 1.5 times the diameter of the hole. So if the hole is 4 mm the bolt should have 6 mm of threads. If your engine does not allow the bolts to have this much thread area, purchase bolts that do from your local hobby shop.
February 1, 2006
Please see the addendum below if you are installing a high performance Nelson or Jett engine.
Great Planes Model Manufacturing