Kimhoff

My Feedback: (22)

I bought a CH ignition that has the timing advance built in. CH told me to set the static ignition at 28-32 degrees before TDC? If this is correct how can the igniton retard to anythig less than the seting of 28-32 before TDC. Shouldn't the static timing be set at 4-8 degrees? I can see see how the timing could be advaced from this point based on the engine RPM that could be measured by the time between pulese.

Can anyone help me with this?

Thanks

RC Extreme power

My Feedback: (24)

Why question them, They have been doing ignitions for longer than we have been using gas engines for model planes, It works set at 28 deg.

http://www.rcuniverse.com/forum/m_8868990/tm.htm

Milton

w8ye

My Feedback: (16)

The timing doesn't advance. It retards

A fast flip past the sensor will retard it about 16 degrees and it doesn't get to full advance intil up around 4500

If you think about it electronically, it could only retard

av8tor1977

My Feedback: (6)

Yes, "auto advance" is a misnomer; it should be "auto retard". There is a computer chip in the ignition that senses the speed (or rather time) that the magnet is under the sensor. At very slow rpms, like when you slowly turn it over by hand, the timing is advanced. That way you can set the timing at your desired max advance. When the engine is turning a few hundred rpms, the ignition retards itself for starting and low speed running, then starts advancing as the rpms rise up to where you initially set it when the rpms reach 4000.

AV8TOR

tkg

My Feedback: (1)

What he said........

pe reivers

also what my strobe tests showed.

captinjohn

[quote]ORIGINAL: av8tor1977
I will say the description how it works is very good. But any ignition tha advances the timing with the RPM increasing...is a auto advance ignition. Capt,n

av8tor1977

My Feedback: (6)

You do love to argue Captain John....

AV8TOR

tkg

My Feedback: (1)

[quote]ORIGINAL: captinjohn


No that is incorrect. An ignition that is an advancer STARTS with the timing around 4-5 deg BTDC. An ignition that is a retarder starts around 30 Deg BTDC and retards the timing at low RPM. As the rpm increases it returns to its starting point. It does not advance, it retards less.
Why don't we just call it Computer Controlled Timing.

av8tor1977

My Feedback: (6)

Thanks Terry; I didn't want to "get started" and get into a huge unnecessary discussion about it. Remember the big "Top Dead Center" debate some time ago?

AV8TOR

pe reivers

[quote]ORIGINAL: tkg

Terry,
It is good to know if the ignition is an advancer or a retarder if you consider how to set the timing.
Advancers need to have the timing set at between TDC and 6° BTDC
retarders must have a setting of 20° - 35° BTDC, depending on engine make and application.

Some advancers, like the VLACH and Falcon are/were in fact super retarders. Because the pickup signal came too late to fire the same cycle, the signal time was stored and used to fire the next cycle! If I am informed well, they used the mean of the last 10 cycles to do that. When starting, these were fixed timing ignitions, switching to super retarding when the engine was running.

captinjohn

Oh...we had fun with that advance-retard thing...yup tis great to know this stuff. That is why it is a good idea to read as much as you can before you try something new!!! I sometimes reply to postings here & there just to get that extra data placed for new experimenters!!!! Best Regards capt,n

pe reivers

Of course ALL electronicaly advanced ignition advance the firing as rpm rise. 'tis just the way how they do it.