RE: Some early digital proportional history
Here is my project F&M Digital*5 system. It has the 7 cell battery pack (tapped at 8.4, 6.0, and 3.6 volts for the servo motors and receiver) and four servos, three that fail-safe to the center and one that fail-safe to the end of travel (low throttle). They are built with Kraft KPS-7 servo mechanics. I believe that this was the second variation of the early F&M system, as the earlier one used Bonner servo mechanics. The transmitter has the Bonner stick assemblies, which are rather crude by todays standards. The airborn system weighs only 26 oz.
If you look closely, you can see that the painted markings at the top of the transmitter case are missing. Unfortunately, somewhere before I aquired it cleaning was attempted with a solvent like acetone. However, with a good photograph I have been able to make a masking pattern for the original markings which the last photo shows. This one shows the relationship to the case and is not the final copy that the silkscreen will be made from.
Oh yeah, the VK Cherokee kit in the background is from the same period. Though the plans show reed equipment (Bonner Transmites) when the kit was reviewed in RCM I think they used a F&M proportional system. It was also on the cover of Flying models with the Boomarang Bipe by Wally Zober in March 1967. An issue that I wore out in the hospital at the age of 12 after having my appendix removed.