Re: Rotax 912 Oil Pressure Sensor Problem
Posted: Sat Mar 08, 2014 6:55 pm
After 2 failures in 700 hours, I have now mounted my sensor on the firewall - will see how long this one lasts.
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Do you know what the resistance in Ohms was set to on your EFIS (I have the same EFIS) for the Equus out of interest sake? I am busy doing some validations before I spend 6K on a pressure sensor on the 912is... Thanks!tigger_na wrote: ↑Thu Jan 02, 2014 9:42 amCheaper elsewhere for me, please. My VDO oil sender unit also broke, giving wildly erratic readings. Luckily I had previous experience with loose instrumentation cabling and decided to limp to the airport instead of making a precautionary landing. My life, so extended, was made miserable by VDO prices, so instead of forking out a thousand bucks for a new sender unit I bought an EQUUS sender unit for 80 bucks and spent the R920 so saved on fuel. The EQUUS also has a 1/8-27 NPT thread, but only a 0-7 bar pressure range, versus the VDOs 0-10bar. Since 7 bar is the maximum allowable oil pressure on a 912 UL, this is acceptable, for me at least.
Unbelievably EQUUS is not able to provide calibration data for their oil sender unit model 9832, so I checked the resistance versus pressure by connecting the sender to a compressor and recording the resistance readings at various pressures. The results are below. Please bear in mind that the calibration was done with backyard (not calibrated laboratory) equipment. It is evident that, if the EQUUS is used as a straight drop-in replacement, your deviation in the relevant range 2-5bar range will be a maximum of 13%, which is really good enough for me. My MGL Odyssey allows me to define any linear pressure-resistance characteristic, so the error of the EQUUS drops to below 8%. Even better.