Elmic Commander chattering...

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Stew
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Elmic Commander chattering...

Post by Stew »

Hi all.

Do any of you experienced chaps know why an Elmic Commander would 'chatter' really fast?!

Stew.
Stew
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Re: Elmic Commander chattering...

Post by Stew »

Hi Phil.
Apologies, I didn't say it was just set up on the bench, connected to a receiver and battery pack, no rubber etc.
I realised late last night I had put the 6v pack on it, and it should be no more than 4.5 I think. The correct pack seemed to stop the chattering..

Stew.
Phil_G wrote: 22 Nov 2022, 23:39 Lots of reasons Stew:
Too heavy rubber
too many turns
pawl stop out of adjustment
rattler not engaging properly
muck under the armature
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Shaun
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Location: West Yorkshire

Re: Elmic Commander chattering...

Post by Shaun »

Hi Stew,

At 6v it would have been screaming out in pain. :D :D

Are you intending to fly with it ?

Shaun.
Stew
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Re: Elmic Commander chattering...

Post by Stew »

To be honest Shaun, yes :shock:
I have an older model that wouldn't hurt me too bad if I planted a balsa tree.. I'd just like to have the experience of flying with a genuine escapement, even if only once.
Just playing with it on the bench at the mo.
Oh, and Tobe managed to tell me what that cute little yellow and black model is in your video. A 'Dick's Dream' apparently. I think the builder modified the front a little, as the original had a more standard cabin. I like the way yours is though. I'm going to build one that way, complete with flappy rudder!
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Shaun
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Re: Elmic Commander chattering...

Post by Shaun »

Is the escapement new or used?

The model was built by Arthur Fox and owned and flown by Dave Boddo, I got it from him years ago with an Ace Pulse Commander.

Not flown it for a long time. Really needs a refurb and get it skyward again.
Last edited by Shaun on 23 Nov 2022, 23:21, edited 1 time in total.
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PaulJ
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Re: Elmic Commander chattering...

Post by PaulJ »

At the risk of showing my ignorance......... If the receiver needs 6V but the escapement only wants 4.5V wouldn't it be possible to put some kind of voltage reduction (a resistor) in the lead to the escapement...... ? :?

Paul
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Phil_G
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Re: Elmic Commander chattering...

Post by Phil_G »

Hard to diagnose without seeing it Stew, any chance of a video?
what receiver? a genuine S/C? relay or relayless?
or a 2.4g rx via a switch?
Obviously it shouldnt chatter at all, you could try momentarily connecting the escapement directly to the battery rather than via the rx, you should get a good solid click with no chatter. Is it defo a Commander? I ask because the Compact had a current saver which could be faulty.
Try the rx driving an LED with a low value series resistor (220Ω or so) it should light solidly on each button press with no flashing.
The only other thing I can think of is the rivets that terminate the coil wires and support the tags, they can loosen or oxidise over time.
PaulJ wrote: 24 Nov 2022, 08:04... wouldn't it be possible to put some kind of voltage reduction (a resistor) in the lead to the escapement......
According to the instruction sheet ( M09 on the Archive page of www.singlechannel.co.uk ) 6v is ok, though I'm sure we never went above 3 dry cells back in the day...
As Paul says, you could drop it with a resistor, say a third of the coil resistance, but I'm not sure why over-voltage would cause chattering in a Commander. In a Compact it suggests a current-saver fault, I vaguely remember Pete having this problem with a Compact, I think he bypassed the current saver, not sure, my memory is really poor. All guesswork until we have more detail from Stew - in particular, we dont yet know whats driving the escapement! :D
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Pchristy
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Re: Elmic Commander chattering...

Post by Pchristy »

My problems with the compact revolved around the current saving circuitry, which the commander doesn't have.

Elmics were intended to run on 3.6 - 4.5 volts. At 6V it may be that the armature is pulling in so hard that it's bouncing. Increasing the spring tension might help.

If you go the dropper resistor route, add a smallish decoupling capacitor. You will need to experiment to get the right value. Too big, and it will make the response sluggish.

Might also be worth adding a reverse polarised diode across the coil. This will suppress any voltage spikes generated by the coil when the voltage is removed. These could be upsetting your driver circuit.
Stew
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Re: Elmic Commander chattering...

Post by Stew »

Hi chaps
I took it out of its case for pictures. I think...its an RCM&E receiver?
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Phil_G
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Re: Elmic Commander chattering...

Post by Phil_G »

Stew wrote: 24 Nov 2022, 17:01I think...its an RCM&E receiver?
100% certain thats an early Macgregor Stew, pre "blue anodised aluminium case" era, the one in the half-blue, half-clear plastic case.

Thats a superregen receiver, very high gain, so without a transmitter switched on it will chatter as it picks up random noise.
Thats perfectly normal and expected. Once it receives a constant unmodulated carrier it will stop chattering.
In a nutshell you need a nearby S/C tone transmitter to be switched on. The escapement should follow the tone button.

Assuming the tx is good and 'on', then if you still have chattering, my suspicions would be with the rx rather than the escapement, you can test the escapement by directly connecting a battery.
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