Petrol ignition modules.

Afternoon all.

Apologies, but I have another in the long line of questions, as I slowly try to understand these noisey engine things...

On the ignition module for the engine I have (a DLE55), I was wondering if the ignition unit would stop working (and kill the engine) if power is removed from it?

In a roundabout way, I am trying to figure out if is simple RC relay in the ignition power line would suffice as an ignition kill switch that is operable from the radio. I definately want a reliable way of stopping the engine remotely (in case of throttle servo failure or similar), and a kill switch seems like a good idea to me.

Cheers
Andy

Have got a couple of these Andy Ign SW But in the heat of combat the one in my Sukhoi didn't want to stop the engine at full RPM when the throttle linkage broke, luckily having a servo operated choke I had a second option and stopped it with choke. They seem to work fine at low RPM but not at full chat. But in answer to your question it just interrupts the live feed to the ignition unit

Marvellous, cheers Brian. I've just found one for £14.99 on the Just Engines website, that seems to do the same think. I'm thinking that it is worth a punt for that sort of money

Andy

You could get it for £13.98 from here http://www.vanderbuiltmodels.co.uk/remote-ignition-kill-switch-403-p.asp
plus the other items like timing etc.

Even better, Cheers Allan!

Andy

Cheapskate!!!
heheheh
LOL
Just joking!
Nothing like saving money!

I've got just the thing for you Andy, it's called a Mackay 30cc petrol engine. You don't have to worry about fitting a kill switch as the bloody thing does'nt run long enough!!

thats a Tim Mackay I think

Spelling Mr B..... spelling

I had a quiet moment this afternoon at work whilst waiting for some FEA runs to finish. So I designed me a regulated ignition kill device! Simple really, but it will take a voltage input from a battery (4 or 5 cell nicad or nimh, 2 cell A123 or Lipo), regulate it to 5v output for the ignition. It also takes an input from a receiver, through a dual opto isolator (to make sure no HV nasties find their way back into the receiver from the ignition), and that allows the ignition to be remotely killed.

Just need to get a little prototype knocked up at some point, and a wee bit of software written for it, and I have me a product!

andy

The only time I ran a regulator on an electronic ignition it induced a chronic misfire which eventually culminated in a deadstick which cost me the model. I'm now sworn not to use one again on ignition

Falon advised me to only use the recommended 4.8v NiMH batteries to power the ROTO ignition unit. Some customers were returning them as faulty but in reallity the units had been hooked up to 6Volt or some other fancifull device. Apparently some ignore the warning. "Oh yes I use 6 volts, more reliable !"
End result ROTO wouldn't supply free replacements.
The agency moved to AID.

Brian Colclough wrote:The only time I ran a regulator on an electronic ignition it induced a chronic misfire which eventually culminated in a deadstick which cost me the model. I'm now sworn not to use one again on ignition

If the CDI ignition unit circuit design is anything like how I would design it, then the issue with a regulator inducinga misfire, is more than likely to be caused by an undersized regulator. The current demands of a CDI unit are very peaky. It looks like the specified current draw of several hundred milliAmps is an average rating. In practice, it is likely to peak at several amps for short periods of time (i.e. milliseconds), falling off to not a lot for a few more milliseconds.

The problem with a voltage regulator, is that unless you design it carefully, they are not particularly good at handling peaky loads, usually resulting in the output voltage being thrown all over the place. This is bound to upset downstream electronics. So the trick is to design it properly in the first place.

I'll give it a try anyway, I've got some suitable parts in the junk box already, and see how it goes on the bench, before commiting aviation with it

Andy

AHHH electrical beep bobs!!!!
Anything past parallel and series, voltages and amps, and im lost!

Sam, when you get to my age your lost before you start

Andy, just run the ignition straight off the A123 cells with a 6Amp diode(cost 70P) in series so that the volts are reduced by 0.7v. KISS

It's an option Allan, although I would still need the ignition kill device then. Plus, tinkering with electronics is all part of the fun for me

Andy