Hi Guys

Did the first high power testing of our setup yesterday.
Renesis 4 port EC2 RD1-C electric pitch adjustable prop on Glasair Super
II RG
Engine sounded good.
On a fine pitch setting she spun out to 7200rpm.
On a course pitch she gets just over 6000rpm.
Our intake manifold is a modified original Renesis.
The length is shortened, Secondaries Valve removed, but kept the
Variable Intake Valve.
Primary and secondary runners are different lengths now unlike the
original setup unfortunately.
At 6000-7000rpm opening the valve provides another 200rpm so dynamic
charging appears to be
working despite the primaries being shorter than the secondaries.

Confession time!
Experienced a small fire from the exhaust where I had some insulation rap.
Turned out I had a very small oil leak from the sump had dropped a small
amount of Mobile#1 on the exhaust wrap which then ignited.
Had extinguishers at the ready so no damage done. I subsequently found
quite a few of the sump bolts were loose (poor on my part).
Hopefully no more leaking oil. Thankful to find the problem on the
ground while testing!

A few issues came up and I would appreciate your brains and wisdom:
1. RPM above 6000 the Dynon Skyview and the EM3 stop reading correctly -
both take their tach input from Injector #1.
     Now if it was just the Skyview units I’d look at the signal level.
But the EM3 is also playing up and has me stuck pondering at present.
     It seemed to go intermittent but and perhaps come good above 7000rpm?

2. On the course pitch, as soon as the rpm gets to 6000 and I continue
to open the throttle, it goes from smooth to massive missing and rpm drop.
     Any thoughts here?
     Related to point #1 above? Don’t think so as on fine pitch rpm
doesn’t read properly but spins faster with no missing.
     Don’t recall mixture when this happened.
     I think its related to load?
     What could cause this?
     a. Fueling - I tried adjusting mixture but with no success.
Thinking I need to experiment more with mixture when this massive
missing occurs.

   b. Spark? Coils are D585’s
     c. Manifold pressure fluctuations feeding back into EC2 creating
fueling issues?

Thanks in advance for your thinking on my problems.

Steve Izett
Perth Western Australia


Do you have a pressure gage or sensor on the fuel flow?

How are the spark coils being driven?

Most coils require at least a 4 ms dwell time.

The engine rotates at 7000 RPM that is 1166.66 RPS
divided into 1000 is   8.57 msec per rev.

A tall order for most control microcomputers.
The computer must calculate the exact time
before the spark is required to turn the coil on.
When the coil is shut off that's when the spark
is generated.

Very very few engines will run at 7000 RPM.
In addition rotaries fire every rev while a 4 stroke
piston engines  fires every other rev.

One of the reasons I invented a new ignition system.

What kind of control computer are you using
and does the company claim it will work with a rotary?

CD ignitions on the other hand will fire when asked
with no dwell time.

We had a fire too :-)

Paul Lamar



HI Paul

The D585’s are driven by Tracy’s EC2 which is programmed correctly. I
could put the CRO on a coil and check the dwell.
Steve

You are probably the first person in the world to try Tracy's system at 7000 RPM :-)

I always hesitate to criticize Tracy because he was the only person making
gear boxes at the time. Now we have Neal making gear boxes so I am now
free to tell the truth :-) Those coils are no where near 4 ms dwell.
Not only that when you run them at twice the RPM they were designed
for they over heat. They were designed for a four cycle engine firing
half as often.

I would say the dwell is twice 4 ms. Never the less I never put a scope on Tracy
system to see how much dwell he was allowing. There is no way for you change
his program anyway. Maybe I am just ahead of my time advocating doing your
own programing with a Maximite. This situation is an excellent example
of why one would  want to do their  own source code.

You Steve are the best person to pioneer in this matter because your already know
how to program a Maximite.  Despite my being half way around the world I will work
with you if you want to do that.

Now the first thing to try is get RX8 coils. RX8 coils are designed for a rotary
that turns 9500 RPM. I know for a fact the dwell time is 4 ms.
One the early RX8 they over heated. But the switching technology in
the RX8 coils was and still is rapidly getting better.

The ideal solid state switch has no resistance. The current state of the art
is only about 50 milli-ohms and still getting smaller. That is the main
reason the coils over heat. The D585's were designed long ago
in the solid state switch time frame.

In that case the dwell in Tracy's program needs to get smaller but
the RX8 coils might work never the less.

Unfortunately I don't think Tracy's system will  work with a cap dis charge system
as is but I can design a small circuit to make that possible.

If you can contact Aden Lindsay he can help as he is an expert
in electronics. Dave McCandless might know him. He has been on
the news letter since day one but I have not heard from him in years.

Paul Lamar

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