LF info 1960's Graupner Grundig radio
08-18-2011, 11:13 AM
#26
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Location: maracaibo, VENEZUELA
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RE: LF info 1960's Graupner Grundig radio
hello sir, I would like to know if you have digital drawings of the plane Graupner Cherokee. I have that model but I had an accident and broke the wing. and I want to reassemble but it is very difficult to get building plans! or if you have someone who would appreciate help me!
08-19-2013, 08:12 AM
#28
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Location: Paignton, South Devon, UNITED KINGDOM
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I bought one of these radios in Switzerland in 1965! I still have it, and it still works - occasionally! Back in those days it was one of he most reliable radios around. They were very popular in our club as any transmitter would work any receiver - they didn't have to be carefully tweaked like the popular "reed" receivers of the time.
The transmitter runs off 12V - originally two 5 cell nicads wired in series. My original batteries had long ago died, so I've replaced them with a 4-cell LiFe pack, which it shares with my Digimite-8 transmitter!
The receiver is a relay receiver and requires two battery packs. The receiver itself runs off 6 to 9 volts. I'm now using a small 2-cell LiPo for this. The servos run off a separate 2.4V supply, for which I use a 2-cell NiMh pack.
As others have mentioned, the large red block is a superhet receiver. The coloured blocks each contain two tone filter units and a pair of relays. The small red block seen in the above picture is the super-regen receiver that I bought originally. It also still works! The transmitter and receiver both use standard 3rd overtone crystals, but I have a feeling that the IF frequency is 470 KHz rather than the more common (nowadays!) 455 KHz, so Futaba or similar crystals probably won't work. (I'm about to move house, so its all packed away at the moment, and I can't check!)
The system was very modular - mine started out as a 4-channel (2-function) outfit with just a single stick on the Tx. Later I bought the 4 channel expansion pack for it which added the extra stick and 4 channels (another 2-functions). I don't think the ten channel was available as an expansion for the transmitter, but the receiver was simply a case of stacking more modules!
When I fired mine up for the first time in nearly 30 years, the transmitter came up straight away, as did the receiver. I could hear the relays clicking, but the servos weren't moving. I carefully opened the filter units and tried cleaning the relay contacts. This isn't easy, but it did restrore full functionality for a while. Just before I packed it away again the servos had stopped working again. Obviously I didn't clean the relay contacts well enough!
The "Bellamatic" servos (two seen in the picture) were centered by springs. However, under "no signal" conditions, the motor was short circuited by the relay back contacts, which made the centering very slow. Grundig came up with an ingenious "bodge box" (the small grey things on two of the modules) which not only eliminated this problem, but enabled you to vary the centering speed via a small knob on the "bodge box"!
The third servo was a progressive one used for throttle, and wasn't affected by the centering issue.
I had many years of happy flying with this radio, initially in a Graupner "Consul" powered by a Cox Medallion .09 (rudder and elevator only), followed by a Veron "Robot" powered by an AM 35 diesel (also rudder and elevator only), then a "Super 60" powered by a Merco 35 (Rudder, elevator and throttle) and finally a Graupner "Taxi" powered by a Veco 19 (also rudder, elevator and throttle). When I sold the Taxi, the radio got retired - that would have been in the late 70's. It was still working perfectly reliably then, but had been superceded by proportional systems.
These were absolutely brilliant radios with a reliability record second to none. I must have another go at getting mine working properly again.....!
--
Pete
The transmitter runs off 12V - originally two 5 cell nicads wired in series. My original batteries had long ago died, so I've replaced them with a 4-cell LiFe pack, which it shares with my Digimite-8 transmitter!
The receiver is a relay receiver and requires two battery packs. The receiver itself runs off 6 to 9 volts. I'm now using a small 2-cell LiPo for this. The servos run off a separate 2.4V supply, for which I use a 2-cell NiMh pack.
As others have mentioned, the large red block is a superhet receiver. The coloured blocks each contain two tone filter units and a pair of relays. The small red block seen in the above picture is the super-regen receiver that I bought originally. It also still works! The transmitter and receiver both use standard 3rd overtone crystals, but I have a feeling that the IF frequency is 470 KHz rather than the more common (nowadays!) 455 KHz, so Futaba or similar crystals probably won't work. (I'm about to move house, so its all packed away at the moment, and I can't check!)
The system was very modular - mine started out as a 4-channel (2-function) outfit with just a single stick on the Tx. Later I bought the 4 channel expansion pack for it which added the extra stick and 4 channels (another 2-functions). I don't think the ten channel was available as an expansion for the transmitter, but the receiver was simply a case of stacking more modules!
When I fired mine up for the first time in nearly 30 years, the transmitter came up straight away, as did the receiver. I could hear the relays clicking, but the servos weren't moving. I carefully opened the filter units and tried cleaning the relay contacts. This isn't easy, but it did restrore full functionality for a while. Just before I packed it away again the servos had stopped working again. Obviously I didn't clean the relay contacts well enough!
The "Bellamatic" servos (two seen in the picture) were centered by springs. However, under "no signal" conditions, the motor was short circuited by the relay back contacts, which made the centering very slow. Grundig came up with an ingenious "bodge box" (the small grey things on two of the modules) which not only eliminated this problem, but enabled you to vary the centering speed via a small knob on the "bodge box"!
The third servo was a progressive one used for throttle, and wasn't affected by the centering issue.
I had many years of happy flying with this radio, initially in a Graupner "Consul" powered by a Cox Medallion .09 (rudder and elevator only), followed by a Veron "Robot" powered by an AM 35 diesel (also rudder and elevator only), then a "Super 60" powered by a Merco 35 (Rudder, elevator and throttle) and finally a Graupner "Taxi" powered by a Veco 19 (also rudder, elevator and throttle). When I sold the Taxi, the radio got retired - that would have been in the late 70's. It was still working perfectly reliably then, but had been superceded by proportional systems.
These were absolutely brilliant radios with a reliability record second to none. I must have another go at getting mine working properly again.....!
--
Pete
Last edited by pchristy; 08-19-2013 at 08:15 AM.
12-14-2013, 06:35 PM
#29
Junior Member
Pete,
Thanks for sharing this story and photos!
I have two of these radios and have tried EVERYTHING to get them back to work.... but NOTHING!
All I can do is display it next to one of my 15 Graupner Boats.
(I just finished another 1967 Gracia sailboat and have posted some images. Have a look)
Any luck making yours work again??? I absolutely love these old things!..
Regards,
Carlos
Thanks for sharing this story and photos!
I have two of these radios and have tried EVERYTHING to get them back to work.... but NOTHING!
All I can do is display it next to one of my 15 Graupner Boats.
(I just finished another 1967 Gracia sailboat and have posted some images. Have a look)
Any luck making yours work again??? I absolutely love these old things!..
Regards,
Carlos
12-17-2013, 11:23 AM
#31
Junior Member
Jay, thanks for your message. I called you and left you a message regarding my radio. I live in Los Angeles so we are close by. Would like to bring it over to see if it can be fixed. Please call me back at 310 505 0988.
12-17-2013, 08:50 PM
#32
Junior Member
Here is a link to a really cool site with lots of Graupner info.
enjoy.
http://rcpedia.elf24.de/text/GRAUPNER
enjoy.
http://rcpedia.elf24.de/text/GRAUPNER
12-22-2015, 12:57 PM
#33
Skimming through an old R/C book printed 1964, I came across a Graupner ad for the Variophon/Varioton S (superhet) transmitter/receiver combo. They list only 5 different crystals (as listed on the transmitter's top plate as well) while the 1967 catalog lists 12. Anyway, there's a remark that the receiver's IF frequency is 460 kHz. For what it's worth...
That was the nostalgia part, now to curiosity: Did you really manage to fly your old set again, did you try at all?
