From 35 mghz to 2.4 - British Model Flying Association Southern Area - SABMFA

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From 35 mghz to 2.4

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From 35 mghz to 2.4 (transmitter conversions)

Having the desire to build an original Kwik Fli 3 model (classic aerobatics) I made the decision to also fly this model with an original radio set, both Kwik Fli and kraft rc being synonomous with Phil Kraft - a truly classic model designer and rc manufacturer. Eventually my transmitter was sourced on Ebay from the states and cost me £30 including postage. The set was a series seventy seven that had plug in modules to enable it to be used on 72, 53 and 27 Mhz. By so doing the set was designed with separate RF section and hence the decoder was easy to identify. Being wary of a transmitter that had not been switched on for 25 years it was only prudent that the decoder was checked to ensure that the functional side of this transmitter - wave form - pots - and each channel output were indeed operating correctly and without deviation. At this point i contacted Mike Ridley of ModelRadioWorkshop to assist (a local supplier who has many years of experience in RC equipment and model electronics) and within 5 minutes we had powered the transmitter and could see the output on the scope of this Kraft series 77 transmitter. The output was perfect, clean and showed that all channels were as good as the day it was produced. Kraft always set the standard for quality and they did not compromise on components - processes and inspection to ensure that every set made was top quality, this was probably why they were unable to compete in the market place when foreign companys saw the potential in the model market. So establishing that the decoder and mechanics were operating as required next step was to link in a 2.4 rf module. I had selected the FRsky module as being one of good heritage as this equipment has proven over past years that it can compete favourably with most major brands of rc equipment on the market. To convert the transmitter to 2.4 all that was necessary was to connect the 3 wires from the FRsky module onto the decoder board, 2 wires connected to power supply and the third wire to output from decoder. We then completed the bind to a FRsky reciever, at which point all servos became operational and the system became complete. Centering and movements on each channel were perfect with no adjustment required (another tick in the box for Kraft quality) and the bind of transmitter and receiver was instant (we checked this by switching both receiver transmitter off independantly with almost instant recovery of control).

The conversions of older Rc sets is becoming popular as many modellers find a way to re-use equipment from the past and build classic models from the golden era of proportional equipment. There is also a resurgance in single channel and modules to convert our old equipment to 2.4 are available ( .

Such conversions do need to be completed carefully and the radio checked afterwards to ensure it is fit for use (as the pilot you are responsible for your equipment and must show you have acted responsibly when completing changes to 2.4) and hence my advert for ModelRadioWorkshop. Mike Ridley has serviced most major brands of Rc equipment in the UK for many years (Futaba - JR) and currently supports Multiplex as well as manufacturing numerous electronic devices to meet specific model requirements .He will gladly help on technical rc issues and can be contacted at email -- his website at

Although we have talked multi proportional sets Mike also has a solution for single channel that can emulate sequential or compound actuators as well as quick blip throttle. see his webpage to view the other products he can supply and or help you with. I should also add that Mike was able to supply the FRsky transmitter modules and receivers for me to help my conversion so a one stop solution. Below are pictures of my Kraft transmitters bought for conversion - you can see both in excellent condition and have open gimble sticks with RF module being inserted at the top, state of the art in there day .......

The Completed 2.4 Kraft transmitters -- here are the Kraft transmitters after completion of conversions At the top of the transmitter the small black plate covers the hole where normally was inserted - it now carries the bind button and the LED that shows status of transmitter. The RF module used was the FRsky and hence the same manufacturers receivers in the foreground . The open gimbal sticks are as good as the day they were produced and the whole transmitter feels comfortable to hold and oozes quality - just like in the good old days . This conversion is very prevelant in the USA with many classic aerobatic pilots still prefering to use their original kraft radios --
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