RV-12 Gascolator

[rgmwa]

Originally Posted by rvbuilder2002

Correct.
The hole is designed to provide for easy use of a fuel sample tube like THIS

Tip: Make sure the hole is big enough to take the sample tube before you paint the cowl.

[D&M Dan]

You must be correct, I will check my plans, although they are an older set that step should be there. I must have been too busy fitting the cowl and some how missed that step. I will order that sampler and drill a hole at the airport.
Thank You

[BigJohn]

Be aware that some sampler tubes have molded protrusions on the sides that make it impossible to slide the tube in the hole. If you run into this simply grind the protrusions off with a belt sander or the like.

[RFSchaller]

I replaced the gascolator drain valve with one that locks open with a twist. I like it for several reasons: it prevents a vacuum lock when you are removing the bowl for insp Cotonou, it makes draining your fuel system easy and I don't need the stem that protrudes above the tester tube. You do have to remember to verify the valve shuts after taking a preflight sample, but that has only happened once in over 100 samples and it was obvious.

[rvbuilder2002]

Originally Posted by RFSchaller

I replaced the gascolator drain valve with one that locks open with a twist. I like it for several reasons: it prevents a vacuum lock when you are removing the bowl for insp Cotonou, it makes draining your fuel system easy and I don't need the stem that protrudes above the tester tube. You do have to remember to verify the valve shuts after taking a preflight sample, but that has only happened once in over 100 samples and it was obvious.

Not always obvious.....
There is at least one RV take-off accident caused by the use of a locking drain ion the gascolator.

RV owners usually learn early on that almost no fuel comes out of the gascolator drain unless the electric pump is on.
If someone is unaware of this detail, it is possible to accidentally leave it open with little to no indication, if the electric pump is off.
Once the engine is started the large leak will obviously have a major impact on engine performance.

[RFSchaller]

Scott, the one time I inadvertently locked it open while sampling the trickle was pretty obvious, and as I said ensuring it is in the correct position is an important part of my preflight. I've owned a Cherokee 180 with this type of drain valve on each gas tank as well as the gascolator for 31 years, so it is second nature for me to check the valve status after sampling. I think the advantages I mentioned make the twist-to-lock valve a good choice as long as reasonable care is taken. You can't eliminate every possible bad scenario with design without losing some desirable features.

[scottmillhouse]

I flushed my system as per instructions when doing the PAP procedures and at 103 hours have had no debris on the screen, bowl or with any fuel samples.

At risk of a thread drift, thought I'd post my recent experience. Just did my first annual and was unable to remove the right rear gascolator screw. There is a nut plate for a clamp inside the airplane that holds the fuel return line as shown on drawing 22-02. I had too much thread showing through the nutplate adjacent to the screw and the extra was just enough to block screw removal. No problem when trimmed flush. In final assembly I probably used too long a screw. This error made a 10 minute inspection take several hours.

[rvbuilder2002]

Originally Posted by RFSchaller

Scott, the one time I inadvertently locked it open while sampling the trickle was pretty obvious, and as I said ensuring it is in the correct position is an important part of my preflight. I've owned a Cherokee 180 with this type of drain valve on each gas tank as well as the gascolator for 31 years, so it is second nature for me to check the valve status after sampling. I think the advantages I mentioned make the twist-to-lock valve a good choice as long as reasonable care is taken. You can't eliminate every possible bad scenario with design without losing some desirable features.

My comment wasn't really for you Rich.... just mentioning it for others since I can confirm the potential for it causing a problem is real (I saw the wreckage that was the result of the forced landing it caused.

BTW, this was on an early RV-6 where someone had used a cherokee gascolator / fuel pump assy.

[RFSchaller]

Scott,

Yep, each builder should definitely consider your position and beware of the issues before they decide what's best for them.

Rich