Fuel Filter

Okay - will try again.

I will be referring to my last aircraft, an ATEC Zephyr kit bult.

All fuel plumbing Gates "rubber" fuel hose (mainly 8mm ID)

Two, in fuselage tanks - 60L Main located just in front of the wing spar. 35L Reserve/Aux behind the front seats.

Main tank; Exit fuel:

Main supply, through in line Hengst H102WK filter -  non return (one way) valve.

Aux/Boost supply, through in line Hengst H102WK filter, 12V electric Boost pump (Facet), T into main supply.

Mechanical pump - fuel manifold - carburettors.

Reserve tank: Exit fuel:Through in line Baldwin BF 7863 filter - transfer pump (Facet) - non return valve - Main tank

Reason for filter selection:

The Hengst H102WK filters are used routinely by ATEC aircraft (not a requirement, the builder can choose their own) - just continued the practice.

The Hengst filters were readily accessible for inspection before first flight of the day - check (with torch) for contaminants..

The Aux fuel tank is not an ATEC approved accessory. The use of the Baldwin BF 7863 filter (significantly larger than the Hengst H102 WK's) is in the hope of less flow restriction (long delivery line) and increased resistance to contaminant blockage (due to location, only inspected at 50 hr intervals).

I had a fuel cut off valve on the main line but never used it. In theory, it was there for an inflight fire situation but as the boost line didn't have one, not sure if it would have had the desired effect anyhow.

Refueling Time:

I use 98 RON, ULP - it seems to go "off" quicker than 95 and certainly AVGAS. In recognition of this, I usually refueled before the first flight of the day - if planning an early start (first light) would do so the day before. In Australia we feel that refreshing "old" fuel (left in tank) with a significant quantity (say 25% or more) of fresh, will restore any lost (through evaporation) performance. Fuel that has been left for a month or more in an open to atmosphere tank, should be discarded (drained) - use in the mower.

When using automotive fuel (MOGAS) it's a very good idea to use a filter funnel, when refueling - amazing what it will catch and also keep your in aircraft filters clean/free flowing.

Thanks I will digest- but a quick observation I did not see a fuel return line from the distribution manifold back to a fuel tank listed- you do have one correct?

Sean wrote:

When using automotive fuel (MOGAS) it's a very good idea to use a filter funnel, when refueling - amazing what it will catch and also keep your in aircraft filters clean/free flowing.

Excellent suggestion

Cheers

I can’t seem to find any flow rate specs for your fuel filters online, nor any data that describes what size microns they will filter. The one I have been using has that data listed on the Aircraft Spruce website. That’s how I determined it meets the Rotax 912 IM requirement for the 0.1mm minimum micron screening, and the flow rate requirements for my particular fuel system as determined by me during the flow test (my filter meets the 150% of max continuous power flow rate and exceeds the IM micron requirement). How did you determine this without the data, or did you find that data? Thanks!

Rotax Wizard wrote:

Sean wrote:

When using automotive fuel (MOGAS) it's a very good idea to use a filter funnel, when refueling - amazing what it will catch and also keep your in aircraft filters clean/free flowing.

Excellent suggestion

Cheers

A technique I’ve adopted when fueling from gas cans is prior to using any gas from a full container, I invert the container so the filler neck now becomes the low point, wait a few minutes, then drain a “gas can sump” sample into a clear glass jar from the inverted container.  In this manner you will identify any problems before you use the can to fuel your aircraft. If it’s clean and clear, pour into your plane, or mower or return it to the can. If it’s contaminated return it to the can and take the can back to the place where you filled the container.