72MHz question

[jtbluefeather]

I have an old JR 72MHz system from the 90's that I am wanting to use in my FT Simple Soarer for the WR attempt at Flite Fest this year. I had it working and had several flights with a 2S 1000 mAh battery, 18A Turnigy plush, a Turnigy 2750-1500 motor and an 8x4.5 prop with everything staying cool to the touch after 10-15 min flights. I plugged in a 3S 800 to see what it would do, and the first flight went well. Climbed faster to altitude, cruised around on low power for 10 minutes and came in. He next flight I tried, it was up for three minutes when the motor slowly lost power over about ten seconds. I had enough altitude to glide it back, and took it back to the shop to figure out what was going on.

When I checked the combo on a 2S again, it did the same thing. But then I plugged it into an Orange rx bound to my dx6, and it ran fine. So I plugged a different power pod into the JR rx and tested it. Again, it ran for a minute or two at half power, then lost power over ten seconds. Tried that setup on the Spektrum, and it ran fine. This leads me to believe there may be a rx/tx problem with the 72MHz set, but I don't know that much about them.

The rx does have a separate slot for throttle and batt, and I've been plugging the ESC in to the throttle and it worked for a few flights. Now I'm wondering if that could be the problem? Or something else?

Anyone have any thoughts or ideas?

 

[Hai-Lee]

Try using a separate BEC for the Rx on the battery input of the receiver and remove the positive power lead from the ESC connection into the Rx on channel 3.

If not a BEC any old ESC used in place of the BEC in the above sentence can be used. You could either join the ESC abd BEC to the same battery or use a smaller and separate battery for the Receiver.

My experience was with an ESC that when it got very warm it would drop all voltage to the receiver. Very near fatal and a few flights with strange outages later I worked it out and now the plane flies brilliantly with 2 batteries and 2 ESCs.