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Weather / Flgt Plng
Fri Mar 27, 2015.
Wishing you and yours a happy, safe and RV-filled
Check ...Justin Ttwilbeck RV-10
I finally got to see the plane with its wings
on!....for a day. With help from Brian and Brandi we trimmed the
flaps and wing root fairings as needed in less then a day! Brian was
a great help and I'm not sure I could have gotten the job done
before sundown without him.
After a few days away, Aurora Australis
returns home with her new tiger stripe livery. It looks better
than I thought it would, especially in the sun! <g>
Manifold Pressure Mystery ...Tango Mike
Manifold Pressure Mystery:
The airplane: RV-4 with VM-1000 and dual Electroair ignitions (left
gold Gen 1 unit with the MP sensor mounted on the EIS beside the
coil packs, and right purple Gen 2 unit with a rev 1 MP sensor
1) VM-1000 MP reads barometric pressure when the engine isnít
2) After start, the MP advances to mid to high 20s with about 900
3) Left advance reads 17 degrees
4) Right advance reads 28 degrees
5) Neither advance reading changes when the manifold advance is
6) During runup, the VM-1000 MP and the advance on each side remain
the same as when the rpm is below 1000.
1) It appears to me that the VM-1000 and both Electroair EISs are
2) Itís important to note that the Gen 1 units have a different RPM
advance curve than the Gen 2 units. I donít have my notes with me at
the house this evening, but I think the Gen 1 units are programmed
to 18 degrees once RPM is above 800, and the Gen 2 units are
programmed to 25 degrees. (I also think the Gen 1 units added a
degree or two of advance for every 100 RPM above 1000, but thatís
not germane to this problem.)
3) With MP advance turned on and working on both sides, the advance
readings at low taxi manifold pressures should be high. Theyíre not,
and they remain at the fixed advance settings based on RPM, close to
the programmed, fixed advance of 18 degrees on the left and 25 on
4) Turning off the manifold pressure advance causes no change in
5) If the VM-1000 were reading normally, Iíd troubleshoot the
manifold pressure ignition advance system.
6) If the manifold pressure ignition advance system were working
properly, Iíd investigate the VM-1000. (Itís important to note that
last year I followed forum member Reggieís procedures for cleaning
the MPT and solved a problem with erroneous MP readings. That and
the fact that the MP reads atmospheric pressure in static conditions
appears to eliminate the VM-1000 as a suspect in this mystery.)
7) Iíve removed the hose from the fitting on the engine and gently
applied pressure and vacuum, both of which resulted in about .2Ē
increase and decrease, respectively.
Investigate the possibility that no MP is being supplied through the
fitting on the #3 cylinder to the VM-1000 MPT and the two MP
Any suggestions would be much appreciated. Thanks.
Welcome Kitplanes Magazine...and their monthly photo contest.
Previous Day's VAF News
Interested in Relocating to 10.5 Acres Outside of Waco, TX?
My late Mom and Dad's property is coming up for sale
here in a few months, and I wanted to give the RV community first
crack at it. 10.54 acres, live oaks over 100 yrs old (one over
20' in circumference), deer, no state income tax and room to
breathe. 9 minutes by car to KACT. I helped my Dad clear
the pastures out around age 13. With less work than you might
think you could operate a Cub out of it. VFR 300+ days a year.
Avg temp 66.5*F (data).
Pics below...click to enlarge.
Zillow info on this property
honor system site by Doug Reeves (contact).
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