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Thanks Ed. I’ll have a look at how we might buffer the signal.
Steve
> On 24 Jul 2016, at 9:57 PM, Ed Anderson <flyrotary@lancaironline.net> wrote:
>
> Hi Steve,
>
> Looks like the "typical" run of problems that many of us have encountered.
>
> In my research, one thing that became clear is that there are very high pressure waves generated in the rotaries intake manifold (naturally that is what is used to "self-turbocharge" the rotary engine). IF you do not have a dampener of some sort between your manifold and the EIC2 pressure sensors - you can get some puzzling results.
>
> I build an instrument for monitoring/control of the Pmag electronic ignition systems (produced by Emags) for piston engines and some folks were having difficulty in that one of their Pmags would lose its TDC timing reference after engine start.
>
> It turns out it was caused by two factors. Some folks were using the old magneto starting procedure whereby they would start on one Magneto and switch on the second magneto after engine start. Well the Pmags have TDC reference set by having the user blow into their manifold tubes. What was happening is the high pressure waves generated during the start on one Pmag generated high enough pressure in the second Pmags manifold line that it thought it was having its TDC reference reset (and by this time engine rotation had it way past TDC). So the user was ending up with one Pmag with its timing 10 or more degrees off TDC. Not good for smooth running. The Emag systems folks have fixed the problem with a Software upgrade that precludes it from happing, but it just goes to show that those finite amplitude pressure waves can cause unanticipated problems.
>
> You might try a dampener in your manifold pressure line if you do not already have one. Folks have used everything from a small hole drilled in a rivet stuck into the line to the small fuel filters for lawnmower engines.
>
> Ed
>
>
> Edward L. Anderson
> Anderson Electronic Enterprises LLC
> 305 Reefton Road
> Weddington, NC 28104
> http://www.andersonee.com
> http://www.eicommander.com
>
> -----Original Message----- From: steve Izett
> Sent: Saturday, July 23, 2016 7:29 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] First full power testing of Renesis 4 port
>
> 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
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