Anybody have this problem......with Spektrum DX7 Radio??[]


Lost 3 planes using Spektrum 7DX
About 600' away and after a couple of minutes of flight the plane goes straight into the ground.
First I lost my nitro Bronco.......Straight into the dirt.... twin engine plane Nitro...I thought it was pilot error    RX7000 Receiver
 2nd I lost my Handyman......a World Models Foam  A couple of minutes and straight down                           RX 6100
3rd I lost my Scale Cessna 182 ......This one hurt     A couple of minutes and straight into the dirt                RX 7000

All different RX's but same tx
Batteries fully charged...No other planes in the Air[]