Update by user Jun 15, 2013
Dad, good idea! If you read some of the posts on RCU about these motors, you'll find many detailing how the crank binds on the back side of a loop. The general consensus is that as the prop unloads on the back side of the loop, the crank is pushed backward to the point where it contacts the rear of the case resulting in a stalled motor and a dead stick landing. Too much play and not enough shim to keep the crank in place.
In addition, the recommended prop range appears to be incorrect. The mid and upper range prop sizes for the 50i, seem to overload the motor in the higher RPM ranges. I've experienced uneven RPM's and a lot of missing and popping.
I mounted this motor on an old Great Planes Giant Aeromaster I found on RCU as an ARC kit. I had, some years ago, a Super Aeromaster with a Fitzpatrick .61 glow. The Super flew like it was on rails. The CRRC motor does not seem proportional in power, performance, and reliability on the Giant Aeromaster when compared to the performance of the Super Aeromaster.
In MY OPINION, I think you'd be better off buying a more reliable motor. DLE are great! More expensive? Yes, but they run right out of the box. If I had not tried to get away cheap and bought a motor from a REPUTABLE and TRUSTWORTHY distributor, I would not be on this site at all.
Original review posted by user Sep 16, 2011
Just over six months ago I bought a brand new CRRC 50i gasoline motor for a new giant scale model aircraft I was just finishing. This motor was DOA out of the box. I tried for two evenings to get the motor to start so I could slowly break the engine in. I followed the instructions explicitly using the recommended 93 octane gasoline and the correct ratio of oil added to the fuel for safe break in. I could not get the motor to run even after replacing the spark plug with a higher quality one. I contacted Maxford USA, the US distributor for these engines, and found that it was under warranty. I obtained an RMA # to return the engine for warranty service. Now begins the problem. There is a practice we use in the model aircraft hobby where we use blue Loctite, the weaker formula, to help keep the propellor nut from loosening and losing the prop. At full throttle and with a 22 inch prop spinning at 7500 RPM the tips of said 22 inch prop are travelling at 281.4444... miles per hour. Hence the practiceof "Loctiting" the prop nut. It's a safety issue. Little did I know that the thread locking compund used by CRRC-Pro manufacturing in China is weaker than the blue "Loctite" we normally use. I was able to just loosen the propellor nut to remove the prop when the whole propellor shaft came loose from the crank shaft. I had to get the prop off the shaft and rinstall the shaft back on the motor to ship, it in its original box, to the distributor for repair. I tried using a strap wrench and failed to get enough torque to remove the prop nut. I had to resort to using a pair of pliers which accomplished the task but also slightly marred up the shaft. Maxford USA was informed of this and they said we'll look at it. They called back after they received the motor and looked at it. They said I damaged the motor internally by moving the crankshaft backward one millimeter when replacing the prop shaft and thus voided the warranty. Moving the crankshaft BACKWARD is a physical impossibility. If there was any movement, which I doubt, it should have been FORWARD due to the direction to tighten the prop shaft back on the crankshaft. They admitted that the crankshaft was not moved at all when they tried to shim the crank into what they thought was the correct position. That position, according to them, caused the engine to bind. I felt vindicated. They still will not honor the warranty and it cost me $200.00 to repair the motor. As far as MY OWN OPINION is concerned, Maxford USA will do anything in their power to AVIOD honoring a warranty. Also, IN MY OPINION, CRRC-Pro gasoline motors do not even make good boat anchors because they are so light. Lesson Learned? Cheap motors are just that. CHEAP JUNK. and Maxford isn't any better! If you're into building and flying RC airplanes and want to try the gig gas engine models, buy a REPUTABLE motor, not a cheap piece of junk like CRRC-Pro.