hi
this happened to my hyper 7, was working ok with the throttle and brake, took it out onto the field and next minute full throttle with no input from me, still had steering but no throttle or brake, failsafe would not kick in.
it ened up to be a break in the servo wire from the throttle servo to the receiver,new servo and it works like a charm.
on mine it looked as though a screw had one of the wire and it had exposed the core...
would recomend double checking this, uprated servo is about