This is a CD4049 inverter running on a 5 volt supply.

The lower trace is the signal out of the upper 2nd gen CAS at a 50 ms
period. That tranlates to 1200 RPM.

One side of the CAS is grounded to the 5 volt supply.

It still works at 100 ms or 600 RPM. It is just ticking over:)

A couple of bias resisters will allow it to work much lower than
that. The scope has a hard time working that slow. I need my other
digital scope to go that slow :)

This is only one of the 6 buffers in this chip.

Paul Lamar

This circuit works down to 400 RPM and lower. How much lower I can't
test at the moment. The 24 volt electric motor is running on only 3
volts.

Paul Lamar



That's great.  This means that the ignition system will not only work
when the engine is running but also when the operator tries to start it
up.  No super duty starter or huge battery is required to spin this
thing up over 600 RPM just to get the sparks working.


  Mark LaPierre


Here is a chip that will work with fraction of a volt from the CAS.
It is called an LM311 comparator.  Been around for 50 years. There are
some new CMOS versions that work even better.
In this movie you can watch the 2nd gen CAS  rotate on less than a volt.

 The CAS is also putting out less than a volt peak to peak  and we are still
getting a usable trigger pulse. Good for hand proping :)

BTW I think what Kevin is talking about is making a leather pocket that will
fit the tip of a prop with a rope attached. Set the prop at 10 AM or so. Use the rope
to jerk the prop 90 degrees. Due to the 3:1 gear box that will rotate the engine
240 degrees which should be enough to start it. If the prop is clocked correctly
each rotor should fire once.

Paul Lamar


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