Hi Don,

 

Teething problems it seems.   I have the older 13B with a RD1-C and a Performance Propeller 74/88.   I had a 76/88 that gave me 5800 rpm static on a nominal day.  I had an inch trimmed off each tip which moved my static up to a nominal 6000 rpm (6200 on a <50F day).

 

 You mentioned you had the quietest plane around presumably due to the two mufflers in series.  I am not certain about the Renesis with the side port exhaust, but the older 13B is sensitive to exhaust back pressure.   You might try removing one (or both) temporarily to see if it has any effect on your static rpm and power.

 

I never copy A to B controller (I always leave B in default mode as a fall back), so can not help you on the problem there – however, I would agree with Tracy that electrical noise can be interpreted by a digital chip as a signal to do something unexpected. 

 

Just guessing, but your EGT divergence would seem to suggest that perhaps your airflow in the manifold changes around 5800 rpm and you are perhaps getting more combustion in one rotor than the other resulting in the diverging EGT.  Hard to figure why - given  your manifold tubes are a mirror image – any photos available?  Where is your staging point?

 

Not using Tracy’s EM-2, so can’t help you there.  However, if Tracy suggested hooking up your EM-2 that way to “make the signal stronger” then he’s the designer – but, if suggested by anyone other than Tracy, I would be somewhat hesitant to do it.  I would suspect that since the serial port signal appears to work for most - at its normal signal level that the “Stronger signal” approach may be a brute force method to overcome problems that might be associated with  electrical noise.  But, again, if Tracy suggested it - then its worthwhile trying.

 

In addition to shielding my pumps and filters with a fiberglass “box” wrapped with aluminum tape, I also have a 2” opening into this box and have a NACA duct feeding it.  In the early days before making this mod and using auto gas, I had vapor and fuel pressure fluctuations – I then found, however, that by turning on my 6psi boost pump it immediately squelch the fluctuations.  Not wanting to run my boost pump all the time, I build the shielding box and cooling air.

 

 

Good luck, hopefully others can offer useful suggestions

 

Ed

 

 

Flying RV-8  N113BR  1.2 hours in the air, 3 flights, 35+ on engine
13B Renesis, EM-2, EC-2, RD-1C, Catto 76/88
Tuned intake, 17.5 in, Tuned exhaust 24 in
Flys like an RV, quietest plane around, long hushpower II and tangential in series
1130lbs empty.  Engine starts easy and runs smooth.

There are a few things going on with the airplane that that I am having trouble with and don't seem to be making any progress on.  Thought some of you might have some thoughts.
1. Occasionally map addresses drop out.  It hasn't happened in a while, but 3 weeks or so ago, as I advanced the throttle there was a rough spot.  I went and looked at the EM-2 in track mode and sure enough, address 43 was at zero.  I manually programed in fuel and it ran smooth again. Running through the Map addresses is now part of my checklist.
2. Starting at about 6000 RPM, the RPM display on the EM-2 starts dropping out.  By the time the RPM gets to 6500 or so it is almost completely gone, but comes back when I reduce the throttle.  I have an optical prop tach so I know it's speed
3. Not getting full power.  On the ground I can only get the RPM to about 5800 static.  Some others with similar setups are getting 6200 static.  Once in the early days of running this,  I could get 6100 on the B controller. Shortly thereafter, I foolishly copied A to B and  b starts acting like a.  I can only get 6800 max RPM in the air, midrange on the air-fuel mixture gauge.  8000ft, 40 degree day.  Additionally, B never works as well as A.  When I make minor changes to A and copy to B, it never runs as well.  It is my understanding that the only difference is there is no Temperature compensation and that the coil disable switches only work on B.
4.High and unbalanced EGTs  If I leave the mixture control just a little below midrange, the EGTs stay pretty close all the way up to 5750 or so.  If I enrichen the mixture the RPMs goes up 125 RPM or so, but rotor 1 (closest to the CAS) starts climbing rapidly to about 1720 degrees or so and rotor 2 starts dropping off, down to 1450 or so.  Engine runs smooth.  EGT probes have been tested.  Pilot has been too busy flying airplane to check if this is happening in the air.  I'll check on the next flight. Oh, no air leaks in the manifold. I've checked several times. All rotor 1 intake manifold tubes are same as rotor 2.  Just a mirror image.

    I have had an e-mail discussion with Tracy and he says there may be an Electrical noise problem.  He wrote, "a cap and a resistor on the injector line to the EM-2".  That's it, but no specifics or drawings.  Anyone have any thoughts on this?  Right now I have EC-2 line 17 hooked to line p3-6 on the EM-2.  It was suggested to do this to make the signal stronger rather than have it just come via the serial lines.  By the way, I'm not an EE or electronics tech so I really don't know what I'm doing, just a guy who can usually follow directions.  I suspect there may be a common cause to all this.  Perhaps it is electrical noise.  It seems to be part of it.  If the noise problem takes care of some of this, great.  Then on to the remaining.  My next experiment will be to run the engine with only the Essential buss on and see if anything changes.  I only have one Ground line off my battery to the Firewall ground.  If I remember correctly, 2 grounds run off that to the engine and that's it.  This cutting edge stuff takes forever.  Thankfully it's not bleeding edge.

A couple of successes:
    My old style fuel pumps were starting to sound funny.  In addition, when one was running and I switched to the other, when the engine was hot, the fuel pressure would drop, the engine cough and a few seconds later the second pump would start pumping.  I would run both for 30 seconds or so to get rid of the vapor lock before shutting off the first one.  I ordered and installed the new ones that RWS now sells.  This problem was less, but still there.  Ended up insulating the shielding around the pumps and this took care of it.  Also the old pumps were very noisy and whined loudly during all flight phases.  Very difficult to hear these new pumps. Nice!
    My engine leaked a little oil from the top of the mount plate.  I had to take it apart when I realized that I had to drill a hole in the engine case for the PSRU oil return.  I didn't get it resealed perfectly.  It didn't leak much, but was a nusence.  An engineer friend told me how to fix it.  Spray the area that is leaking with Carbon Tet based brake parts cleaner and let it evaporate.  Coat the area with clean silicone.  Pull a vacuum on the engine with  vacuum pump.  I hooked mine up to the Crank Case breather tube going out the top of the oil filler cap.  I let it set for 24 hours and no oil leak!  Now that's nice!

I notice that there is a provision for a 2nd CAS to the EC-2.  Has anyone done that and how is it done and where to mount?  I know about using only aluminum for mounting the CAS.
I've come to understand the Mixture monitor and like it!  It would be nice if there was a wide range O2 sensor that gave more of an analog response rather then the almost on/off reading that we now get. Anyone know which one might work and if you are using one?

Thanks,
Don Walker





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