Mailing List flyrotary@lancaironline.net Message #16786
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] Re: Microtech EFI and Tuning, was Re: [FlyRotary] Re: Bad day at the airport
Date: Wed, 9 Feb 2005 10:55:07 -0600
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
I got up to 5100 rpms static, and most people told me that the prop would most likely unload in flight.  How can I obtain more than 5100 rpm's unless I fly it?   
 
 
Hi Paul,
 
I asked Tracy that same question when I was first tuning my EC-2.  The answer (for his unit) was that it didn't matter.  The system bases it's fuel injection pulse width on MAP, which will be nearly the same in static runs as it is in normal climb speeds.   When your prop unloads in flight, you run higher rpms, but that doesn't change the pulse width requirement for each intake cycle at a given MAP.  It just means you need more pulses, because you have more intake cycles.  
 
It's VERY important to realize that everything I just said was based on Tracy's EC-2.  There's a very real chance that the MicroTech DOES care what the rpm is.  I know that the Power FC computer in my FD had a fuel injection and timing table that was based on RPM and MAP.  This gives you more power to tune, but as they say, with power comes responsibility :-)
 
FWIW, I really do like the MicroTech unit, and I thought really hard about getting a couple for the single rotor project, but eventually went with what I know, which is Tracy's EC-2.   Part of that decision was based on having a backup controller if I ever suspected a problem, though it sure would be nice if someone would include the ability to save and restore tuning parameters (between slathering foam and fiberglass on a clapped out travel trailer)  :-)    I also like the built in backup (which would have ruled out an EFI tuning issue for you), and don't quite know how you'd wire two MicroTech's together.   I also like the mixture knob, which is powerful enough to overcome almost any tuning mistake.  I also felt it was safer for me to have only one unit to try to remember.   
 
Hang in there Paul.   Give this some thorough consideration before doing anything drastic.  I seem to recall you giving me some similar advice not long ago.  
 
Cheers,
Rusty  
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