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October 29, 2020, 19:57:52 pm

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RC Flight Chatter / Re: how did you start messing ...
Last post by pooh - Today at 18:53:49
Quote from: FlyinBrian on Today at 18:47:07You describe the Reed relay system and it really did exist.

Thanks, I couldn't recall the "reed relay" definition. Pleased to see that I am not entirely losing my grip...

The concept (reed relay, not my lack of grip) of such a crude system must seem strange to our younger members - even I could have designed something a lot more effective using electronics 40 years ago, but the components and power consumption were a totally different thing. I do recall trying (unsuccessfully) to make a radio control transmitter and receiver using "acorn" valves, although I did have great fun making a small transmitter with appallingly wide harmonic output and standing outside a TV shop and watching all the screens in the shop window collapse into lots of wavy lines when I switched it on, hidden in my pocket...
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Quote from: pooh on Today at 18:00:36IIRC then came multi-channel, using tones to control the individual servo channels? I seem to remember a bar-shaped electromagnet with a sort of comb above the long narrow core, so the "teeth" vibrated as the tones were supplied and the one at resonance moved the furthest and made contact electrically whilst the others didn't make contact.

Or is that something plucked out of my demented memory?

You describe the Reed relay system and it really did exist.
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RC Flight Chatter / Re: how did you start messing ...
Last post by mart49 - Today at 18:08:16
From a very young age I built Airfix kits,usually bought with pocket money from Woolworths. Then one day in a sort of model/craft shop I couldn't find a !/72 kit I fancied I bought an all sheet high wing rubber band model sort of Cessna-ish. I built it, it flew well, had hours of fun with it, hooked. next was free flight,Vic Smeed Debutante, Frog 80 powered, didn't fly well being under-powered and flown by an inexperienced schoolboy. Thinking back to where I lived a couple of years earlier a neighbours son flew F/F in a meadow at the front of the house. A diligent search of the APS  hand bool identified two models a Hot Canary and a Vic Smeed Mamselle that he flew. Got the Hot Canary plan built it. Flew really well, now I'm really hooked. Mamselle then a little C/L and then single channel. Brian I had good experiences with the Elmic Conquest. Then Galloping Ghost. The model definitely galloped when you applied up elevator and the pulse rate went right down. Then RCM&E  digital.... On the bench at the moment is a scaled up Hot Canary, a photo copy of the plan I bought in 1962, who says modellers are hoarders?
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RC Flight Chatter / Re: how did you start messing ...
Last post by pooh - Today at 18:00:36
IIRC then came multi-channel, using tones to control the individual servo channels? I seem to remember a bar-shaped electromagnet with a sort of comb above the long narrow core, so the "teeth" vibrated as the tones were supplied and the one at resonance moved the furthest and made contact electrically whilst the others didn't make contact.

Or is that something plucked out of my demented memory?
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RC Flight Chatter / Re: how did you start messing ...
Last post by dickw - Today at 17:47:41
Galloping Ghost was much more "sophisticated" (I use the term loosely!) than the sequential escapements, as it provide a sort of proportional control of a continuously moving (vibrating?) rudder and elevator. The single control channel was pulsed at a fairly high speed and by varying the rate of pulsing you could move the elevator and by varying the mark/space ratio you could control the rudder. Have a look at the following video which shows the same Mighty Midget "servo".

https://www.youtube.com/watch?v=IBxXsRwRn1M

Dick
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Quote from: pooh on Today at 14:22:20The Elmic used a rubber band, twisted, to provide the force needed to shift the rudder (single channel only, transmitter on  or off) Every "on" blip of the transmitter caused an electromagnet to release the motor shaft, and an escapement (like a clock) allowed only 90 degrees of rotation for each blip.
The rest of the mechanism moved the rudder from centre, to left, to centre, to right (can't be sure which way round it went but you get the idea)

So if you were going straight and want to turn left, just one blip. If you wanted to turn right, you blipped again to get straight on, then again to get right. You had to remeber which "straight on" you were in to know how many blips got the desired result.

Ahhh, yes, the delights of the sequential Elmic Conquest "bang-bang" escapement. They were a complete pain in the bum.  Apart from having to remember which way your last command went, there was the ever-present problem of the escapement skipping due to engine vibration or, more commonly, a touch of radio interference. Nightmare.

The way to go was with the Elmic Commander.  This one always started from the same position, so it was "once for right and twice for left" and was far more reliable.
Then, of course, there was the Elmic Compact with kick-up elevator, which required three presses on the button.   ::)
Happy days.
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RC Flight Chatter / Re: how did you start messing ...
Last post by pooh - Today at 14:22:20
The Galloping Ghost was, IIRC, the next thing after the Elmic Escapement mentioned earlier.

The Elmic used a rubber band, twisted, to provide the force needed to shift the rudder (single channel only, transmitter on  or off) Every "on" blip of the transmitter caused an electromagnet to release the motor shaft, and an escapement (like a clock) allowed only 90 degrees of rotation for each blip.
The rest of the mechanism moved the rudder from centre, to left, to centre, to right (can't be sure which way round it went but you get the idea)

So if you were going straight and want to turn left, just one blip. If you wanted to turn right, you blipped again to get straight on, then again to get right. You had to remeber which "straight on" you were in to know how many blips got the desired result.

Apparently, according to Dennis, you could loop by setting alternate left and right, skipping quickly through the centre positions, as a turn effectively lifted the "outer" wing and the next turn lifted the other wing, so you started climbing and finally went over the top!
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RC Flight Chatter / Re: how did you start messing ...
Last post by dickw - Today at 14:05:11
Sort of - it's a Galloping Ghost "servo" - it gives a sort of "proportional" rudder and elevator control from a single pulsed channel.

Dick
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RC Flight Chatter / Re: how did you start messing ...
Last post by Tabsdad - Today at 13:12:00
Quote from: dickw on Today at 13:02:32apologies for the upside down image - it's the correct way up on my PC!
July 1960.jpg

Is it a homemade servo?
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RC Flight Chatter / Re: how did you start messing ...
Last post by dickw - Today at 13:02:32
After playing with a few basic KK kits when very young as most kids do, my real introduction to model flying was when I saw the attached drawing in a magazine that a classmate was reading on the bus on the way home from school. Next day I went out and bought a copy of the magazine (Model Aircraft July 1960) just so I could try and understand what it was I was looking at.
I have been an aeromodeller ever since.

Dick
apologies for the upside down image - it's the correct way up on my PC!
July 1960.jpg
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