I am desperately trying to get
the single rotor running in the airplane. The engine on the
test stand is just humming away, and when I tried the one in
the airplane a couple of weeks ago it did not do anything.
No ignition!!! cranking too
slow??? starter cable too long??? CAS signal too weak???
The ignition fired when I
took the plugs out of the rotor housing, but not when they
were in the housing. The crank speed difference is 240 vs 320
RPM. The engine on the test stand is already so free that it
does crank about 360RPM. Solution? Making a larger diameter
trigger wheel to make up for the slower crank speed. Turned
out to make no difference. What is going on?????.
My ignition system is a MSD
Street Fire unit. At this point, I decided to have a closer
look at the trigger characteristics of this unit. After
running it on the bench with all sorts of triggers, it turns
out to require a minimum pulse repetition rate at which it is
firing no matter what voltage or wave shape of the trigger
signal. On top of that, a build in trigger indicator light
works at much slower trigger signal the coil actually fires,
creating a deception when testing.
All that seem to be not a
malfunction of one unit because I have two units doing exactly
the same thing.
Before I found out what is going
on, I contacted MSD by phone and was told to hook it up
correctly, and if it does not fire send it back to them. Later
I sent in some more questions by email which were never
answered.
Final solution! No CDY. Using two
individual coils with a TSI igniter each. No more low speed
issues.
Installation on the test stand is
complete, and will be tested in the next two days. If nothing
bad happens, installation in the airplane will be competed in
a couple of days.
I hope this is not to confusing.
Congrats on finding the problem, but if it will fire at very low
rpm, you may have the same safety issues as magnetos. (Have to keep
treating the prop like a loaded gun...) I think Tracy codes a
minimum rpm for fire into his controller as a safety feature.