rbort Elite Veteran Location: Franklin, MA - U.S.A.
| engine bogging downYou got too much blades for the engine and pitch settings.
If you fly 680mm blades, you can support somewhere around 10.5 degrees on the top end at say 1700 rpms.
If you fly 700mm blades, then the top pitch will drop to +9.5 degrees to support 1700 rpms.
If you have 710mm blades, then naturally +10 is too much degrees. Of course if you put a tuned pipe on it will increase the engine power and hence you can support more pitch.
I personally use the Min Air rear can muffler (the one that tucks in behind the frames), and I use the governor on the machine. With 700mm blades, this is what I had to do.
For 1500 rpms, I have +10.5 degrees and I can turn that all day.
For 1600 rpms, I have +10 degrees and the engine maintains that.
For 1700 rpms, I dropped the max pitch to +9.5 degrees to maintain the 1700 during the full power climbout.
Basically use a sky tach on the ship and have someone tell you if you are maintaining rpms at full power, or just listen to it if you don't have one. The rule of thumb is, the faster you want to turn the blades, the more work on the engine so you need to drop the pitch a bit to maintain a good balance. As the blades are turning faster, you will still climb out at about the same rate even with the less pitch.
When I was using 680mm blades, I had power to spare and I was +10.5 degrees on all three rpms. In that case I probably could have ADDED pitch to say +11.5 for 1500rpms, +11 for 1600, and left the +10.5 for 1700. However, I like the bigger disk for extra lift and more hang times on the autos, so I just dropped the max pitch a bit to keep the engine happy.
For you, either use a tuned pipe to increase the power, or drop the max pitch on the higher rpm settings to prevent the engine from bogging down.
Good luck and enjoy!
-=>Raja. |