I got a new toy in the mail today from Tower. It's a Futaba optical tach sensor that mounts on the plane, plugs into the RX and sends RPM data to the TX in real time. Now I can find out how much an engine unloads in the air and in a dive. *****in' Betty (the radio's female voice) will tell me the rpm every time I flip the appropriate switch. She also tells me the speed via GPS. Altitude, distance and rate-of climb/descent are also avail. from the GPS module. The GPS and RPM modules are less than an ounce each. For the Demon, I'll have to break out my headphones so I can hear Betty over the screamage.