RCU Forums - Need help on power train

[&o]

Have a serious question. Sent my son in San Fran. a completed Ultimate, with the E-Flight brushless, 6.33:1 gear box,12.7 slowflyer prop (came with the Ultimate). Has an FMA M5 dual conversion receiver, a Jeti 8 amp ESC (which I also have on my Ultimate), and an 800+maH LiPo KoKam battery. Four mini servos, and also sent him the Hobby Lobby Jeti "programmer" card. Set it up exactly like mine.

Problem is that his motor cuts out after only a short time (about 40 seconds) in the air. Ultimates do not glide real well! He is a very, very good electric flyer, has been since he was 16 years old (35 now!) but we are both very puzzled by this. He has the LIPo battery charger which I got from Hobby Lobby for the Christmas gift , and knows how to operate it. He actually explained the complex charger I have to me, which can charge either LiPo or Nicads.

He appears to have the transmitter set up correctly. Exp on ail, elev, and rudder. Nothing set on the throttle. He has confirmed that with everything plugged in and working. In fact, he has securely fastened the airplane and run the motor at full throttle for 8 minutes. No problem. We are stumped because the FMA receiver has passed brutal range checks, and he has also run the motor at full power at extreme range!

He claims that the battery is charging correctly. He does disconnect the battery after charging, and also after each flight (or attempt!). Do not ask how I found that out! He and I are very puzzled by this thing.

Please help if you think you know what is going on.

Thanks,
Bill