Oscar Avalle Posted July 12, 2012 Report Posted July 12, 2012 As part of my panel upgrade I installed a new JPI 730 with fuel flow (FF). I was wondering if somebody had an approximate value for the K factor for the FF so I could program it into my JPI and fine tune it later . As usual thank you very much your help.
jetdriven Posted July 12, 2012 Report Posted July 12, 2012 Isnt the K-factor printed on the fuel flow transducer?
MooneyMitch Posted July 12, 2012 Report Posted July 12, 2012 I suspect if you provide your fuel flow equipment to JPI tech. Support, they will have the K factor information you are seeking. I found this to be true with Insight tech. Support. Also, you might just check on your JPI head as that information may be documented on the placard with the p/n and s/n.
Bolter Posted July 12, 2012 Report Posted July 12, 2012 On my JPI fuel flow, the K factor was hand scrawled on a little tag in the packaging with the transducer, not the display. It was hard to read, and the "K" looked like a "16" to me, so I thought it was something completely different until corrected by my A&P who knew what he was looking at. Look though everything you received a second time. Or maybe your A&P already entered in the value off the tag? FWIW, I adjsuted my K value over about 5 fill ups. 3 to confirm a typical reading, each at least 30 gallons, then 2 minor tweaks as it was over-reading more than I thought necessary even as a safety margin. -dan
Oscar Avalle Posted July 12, 2012 Author Report Posted July 12, 2012 Thanks for the recommendations...I just called JPI and asked them. They said that the K factor was either 30 or 85 and that I should try both and see what works.
Oscar Avalle Posted July 12, 2012 Author Report Posted July 12, 2012 Jim, thank you. As I mentioned in my other post, I am now waiting to get back in the air and try everything out... I am just concerned after all these upgrades that something may (will) not work... as expected. Otherwise the panel is really nice. The avionics shop did a great job and not too expensive.
rahawk Posted July 16, 2012 Report Posted July 16, 2012 I just installed an edm700, and the K factor was on the transducer. It was 29.86. it is very accurate. There is a formula in the operating handbook that will help you to tweak it after several fill ups. Mine was within .3 of a gallon after burning 35+ gallons.
Lood Posted July 17, 2012 Report Posted July 17, 2012 30/85 sounds about right. I calibrated mine twice after two flights, each lasting almost 3 hrs and it came out at 85,???. That's for liters, so I suspect the "30" from JPI to be if you're ure using Gal, instead.
Awful_Charlie Posted July 17, 2012 Report Posted July 17, 2012 The K factor comes from the number of time the small impeller turns for a volume unit of fuel flow, and the head unit has to sort out the corrections for USG/lbs/litres/ImpG or whatever. I don't know what the US retail limits are, but years ago when I worked in a UK auto fuel retailer, the retailer was allowed -0.5% to +1% volume of fuel against the pump indication at full flow. Depending on what you are measuring, and allowing for fuel expansion/contraction with temperature (density decreases by about 0.5% per 5 °C (9 °F) increase in temperature) I would suggest that when you get consistently to within 2% you are close to the limit of the equipment on the plane and at the refueller can resolve.
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