A bitsa radio DT system for free flight models
I was getting fed up with long
retrieves in windy weather, digging models out of trees and wading about in
lakes. A radio DT (RDT) seemed the thing. Whilst there are commercial devices
that might do the job, the idea of a homebrew caught the imagination.
The BMFA Free Flight Rule Book para 3.1.1 suggests.....'that a single transmission for the purposes of DT is allowed for free flight models. The rules disallow transmission on 27/35/40MHz and recommends use of the 2.4GHz frequency'.
A 2.4Ghz Futaba RF module was procured (£30) together with a Phil Green encoder (£10) which supplies the relevant servo signal. An enclosure, a push button switch, an on/off power switch and a 9v pp3 completes the TX components and half an hour with a soldering iron hooks everything up. The airborne system is a Lemon DSM2 2.4Ghz receiver (£8) powered by a 50mah LiPo . This drives a 1.8gm nano servo via a mouse trap. The airborne system weighs 6-7 gm and is shown below. The battery shown is 120mah 1s and was replaced by a 50 mah 1s for flight testing.
Hook up TX schematic is shown below with a parts and supplier list:-
The system has found duty in a free flight dlg which will be tested at Luffenham at the Area events. If you are interested in this, find the PMFC flag and ask for me.