Citizen-Ship was an early
commercial manufacturer of radio control systems. When you see that they were producing 8-channel units back in
1958, you might be amazed. However, in those days each channel was a single direction of control. So, an 8 channels
in 1958 was equivalent to 4 channels today.
the schematics show, circuits from 1958 are a lot different from those used today. There was no such thing as an
integrated circuit; everything was built up out of discrete resistors, capacitors, inductors, and transformers.
Vacuum tubes preceded discrete transistors, which have both been replaced by ICs. Especially in circuits like transmitters,
you will still find discrete Rs, Cs, and Ls, but they will likely be surface mount types rather than having wire
leads for connection to the circuit board. Click on the thumbnail to the left to view the designer's datasheet for
the 3V4 pentode tube.
R/C Equipment: Citizen-Ship 8-Channel
Circuit diagram for Model MST·8 Transmitter.
Circuit and photo of MSR-8 receiver.
Citizen-Ship's MST-8 transmitter
While the new Citizen-Ship 8-channel simultaneous reed transmitter and receiver may at first glance appear similar
to other apparatus, they have significant differences. One of the most surprising is the fact that both units sell
for just under a hundred dollars each. The relatively low cost does not reflect any short cuts in quality or performance.
Model MSR-8 receiver, intended for 2714 me operation, is a compact unit featuring a single tube detector, followed
by two transistor amplifiers. Output feeds into an 8-reed bank which controls eight sensitive relays. The makers
provide headphone connections for test purposes. For best results the reeds are used as follows: Two highest tone
reeds - rudder; next two - ailerons; next two - motor speed; two lowest - elevator.
Thus, either elevator position may be had reliably with either position of rudder or ailerons; also, motor speed
may be changed at will while rudder is being held either right or left. Relays are all SPDT for use with motor-driven
servos. Escapements can be used but are not recommended where simultaneous operation is desired. While reed adjustment
should not normally be required, it is quite simply accomplished by means of screw contacts.
The receiver is mounted on a sturdy metal chassis, with tube, transistors, reed bank and relays on a phenolic
upper plate. Over these goes a metal cover, open at each end to facilitate connections to the relays, which are
mounted so their terminal plates face chassis ends.
Model MTS-8 transmitter is handheld. Main control, a sturdy "stick," moves up and down for elevator action,
sideways for rubber or ailerons. Alongside the stick is a lever switch which is normally in position to give rudder
operation when the stick is moved sideways; when this switch is pushed upward however, the ailerons are controlled
by stick side movement. Two motor speed buttons are at the left side of the transmitter face. It is quite feasible
to use a motor control system that requires only a single audio channel, such as an escapement or Multi-servo. Other
channel might then be used for some such control as flaps, brakes, etc.
Makers of reed equipment have learned that great tone stability must be built into high class electronic organs;
(Please send me an e-mail if you would like the rest of the article scanned.
I missed the last couple pages while I had the magazine out the first time.)
As always, I try to accommodate requests for reprints of old articles. I do not publish plans full-size because
the Academy of Model Aeronautics still provides
many of them for a small fee, and I don't want to take business from them. If you absolutely cannot buy the plans
anywhere (legitimately), I will send you my higher resolution scanner file(s). The potential exists for image distortion
with my scanned plans, so you are safer trying to obtain originals anyway.
Citizen-Ship's switching system
Posted December 18, 2010