For those unfamiliar with reeds... this was a system which used a different audio tone for each channel,and typically provided
between 3 and 12 channels. Imagine a childs musical keyboard with 12 keys - each note would have a different effect at the receiver.
The receiver had a bank of tiny reeds, one for each channel, each of which vibrated like a tuning fork in sympathy with one of
the 12 tones. This vibration was amplified either electronically or with a relay to drive a servo in one direction.
Each function needed two channels - left was one, right was another. Up was a third, down was a fourth channel, and so on.
A lot of the early reed transmitters had only one tone oscillator and so were non-simultaneous - you could
This is because each control transmitted a different audio tone, like playing a piano with one finger.
Then came Bi-Simul radios with two tone generators, where the left-hand side of the tx (throttle, elevator, elevator trim*) used one tone generator and the right-hand side (rudder, aileron) used another tone generator so... Eureka! you could hold rudder AND elevator AT THE SAME TIME! Fantastic!
Each function (rudder, elevator etc) on the tx had a separate sprung-centred switch, and the appropriate servo shot from neutral to full left (or whatever) with no in-between, then centred when you let go of the switch. Each direction of the switch was a separate channel or tone, so aileron, elevator, rudder & throttle needed 8 channels.
For the throttle, you used a different type of servo (yes, you had to specifically buy a throttle servo for throttle!) that was just nudged by the tx switch, blip it up a bit, blip it down, hold it to go to full or tickover. No centreing.
Because the elevator, just like the other channels, was bang-bang, all or nothing, it couldnt be trimmed off-neutral to correct a diving tendency for example. If you wanted elevator trim, you had to have ANOTHER SERVO like the throttle one, which you could nudge up & down, and that was mechanically linked to the elevator servo either via a bellcrank ,or push/pulling the ele servo on a sliding mount.
Actually the term 'reed' tx is a misnomer, the rx had the reed bank, like a row of miniature tuning forks. Each reed in the bank of 10 would respond to a different tone from the tx. You had to occasionally retune the tx tones so they matched the reed in the rx perfectly - like tuning a piano to a tuning fork - repeating for each channel.
The receivers typically used a 9.6 volt 500mah nicad (called DEACs at the time) with multiple voltage taps. A full-house airborne pack, battery, rx, & 5 servos weighed almost 2 pounds.
Still taking that ultra-reliable 2.4g 7-channel fully proportional, no frequency control, lightweight set for granted?
|Phil's Orbit 10-channel reed set, soon to be flying again after almost 50 years|
|Shauns OS Minitron, it really is immaculate.|
|The OS Minitron again.|
|This is one of two RCS Competition-Ten reed sets owned by Shaun. This one was in reasonable condition but has been restored as far as possible whilst keeping it original. Note the label 'trim' for elevator only. This required a separate servo in the model, hence no trims were available on any other channel!
The servos are Climax Servomites which were supplied on a PCB base which made most of the interconnections. The elevator trim-bar can be seen at the top, the control push-rod connected about 2/3 the way between the trim servo and the elevator servo...
|This similar set was in a shocking state - its electronics were corroded beyond repair & its case battered and rusted - and therefore an ideal donor for a conversion. Its been cosmetically restored to look as near original as possible and given a new lease of life on 2.4g using Phil's reeds emulation encoder and a Spektrum RF module.|
|Inside the back cover - simple wiper switches, and enough room to keep rabbits.|
|Shauns Remcon 12. This was supplied as a self-build kit. Phil also had a Remcon 12 in 1968, but it was a home-made copy of a clubmate's kit-built one!|
|And Phil's converted 2.4g Remcon 12. No attempt has been made to restore it aesthetically, I like the 50-year-old look!|
|Shaun's Miniten reed set.|
|Phils British-made Ariel-Electronics 8-channel reed set.
Theres a story behind this one! When I was a young lad flying single-channel, I saved all my milk-round money with the intention of buying an Aerial-6 which was the most affordable reed set on the market at the time, and was widely advertised in the magazines.
Selective rudder, elevator and the possibility of elevator trim would have been bliss in my gliders!
Needless to say it never happened, but 40+ years later I finally have an Aerial 8!
|The Ariel and its matching receiver was very kindly donated from a deceased modellers estate, RIP RDW. Receiver photo to follow.|
|The Duo-ten, predecessor to the Mini-ten (above), bi-simultaneous, and designed to be "Super Slim" in stature (!) by Geoff Chapman, who later formed Remcon:|
|The Duoten after a bit of spit & polish...|
|...and fitted out with a full complement of batteries|
|Not one of ours, but an antique ED (Electronic Developments) 3-channel valve reed set.
In the receiver, note the bank of three reeds of different lengths, responding to three different tones sent by the transmitter. This was a floor-standing transmitter, with the remote hand-held controller seen here on an umbilical cable.
|This is a PEP250, restored cosmetically and electrically by Shaun. It appears to be a four-channel reed transmitter used on a model boat. We'd like to know more about this one. PEPxxx was a naming system used by Fleet, could this be an early Fleet reed prototype?|
|Inside the PEP250: It is built on perforated board but otherwise has some Fleet characteristics, like a centre-loaded tunable aerial:|
|REP 3 channel reed receiver:|
|Inside the REP 3 channel reed receiver
The reed-bank is plainly visible as are the three relays. These were necessary as the reeds could only pass a tiny, intermittant current, but enough to operate the relays, which in turn operated the servos. 'Relay' servos had no electronics inside at all, they were purely mechanical. Relayless servos had an amplifier which could switch the motor from the tiny reed current.
|and a close-up of a 10-channel reed bank, also by REP. This is a cheap-&-cheerful reed bank with adjustment by bending the upper contacts. Posh ones like the ones used by OS had tiny adjustment screws one each upper contact. In use, the transmitter tones would agitate the reeds strongly such that they could easily be heard, rather like 10 tuning forks:|
|Here are some old Taplin servos, these are general purpose relay-driven servos & could be driven by a reed or a S/C receiver:|
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Phil Green & Shaun Garrity, of the Pontefract PANDAS club
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