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[October 30, 2010]


The wind forecast for this weekend looked a little unfavorable. I am stuck taking off from runway 34 to stay away from the town of Westminster for the first 5 hours, thanks to the FAA. Today the winds were a little stiff for my likings - 10 kts direct crosswind, slightly favoring runway 16. I had a few things to take care of so I figured why not put my time to good use at the hangar.

I took a closer look at my interference between the mixture arm and the lower cowl. Turns out the mixture arm isn't hitting the cowl. It is the castellated nut on the end of the bolt. I figured I could spin it around and see if that fixed the problem.


Sure enough, turning this bolt around fixed my problem. And it didn't interfere with the fuel injector servo. I like those kinds of fixed!


I worked on a bunch of other things today also. One thing was understanding the engine hour timer on the Grand Rapids system. Turns out the EIS engine monitor keeps track of time. And it only keeps track of HOBBS or Tach time. HOBBS time is the default - it starts measuring time as soon as the engine starts spinning. You can set this to a pseudo tach time by setting a parameter on the EIS to only start the engine time after a certain engine speed has been exceeded (I later determined 1,250 RPM is what most manufacturers of EFIS's use). So here is my dilemma. I want to do engine maintenance according to the tach time, but log my airframe time in hobbs. It doesn't seem possible with the grand rapids system. I looked into installing a hobbs meter (On the subpanel or another auxiliary panel), but that required another oil sensor which would start the hobbs meter as soon as oil pressure was detected.

After doing some more research on the issue, I found a perfect solution. The oil pressure sender manufacturer (VDO) makes a dual-output pressure sensor. One output does what the sensor does now (resistive oil pressure sensor), while the other output closes a circuit once it senses pressure above 4 PSI. That new output would be perfect to wire in a HOBBS meter. Also, I can use it to rig up an auxiliary oil pressure annunicator light. The cost of all of it isn't too bad either. The sensor is around $35, and the hobbs meter is about another $40. I need to run to the airport to see what the part number of the sensor is that I have now so I can buy the right new sensor. Great, one problem solved!

The rest of the day I spent inputting all of the engine power charts into the EFIS's to get percent power. The suck thing about the Grand Rapid's EFIS's is I needed to input this data twice! I used Carl Morgan's power charts he has posted at http://www.rvproject.gen.nz/grt/EnginePerformance.xml. Lastly today I filled up the tanks full of fuel. All I can say is OUCH! The winds don't look favorable tomorrow for flying either, however on Monday and Tuesday they look perfect. Go figure, the days I have to work, the winds are where they need to be!
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