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.
Charlie