thinking out loud about dip stick fuel guages.

[Dan_E_Root]

Your local pilot shops and catalog stores offers graduated dip stick gauges for fuel measurement for $12.00 or so. The universal gauge even comes with calibration instructions.

Why anyone would pay so much for a plastic tube with some markings on it?
I thought graduated laboratory pipets would be a good alternaive, but only found them in glass or polystyrene. Glass breaks, and the polystyrene probably breaks down in gas. Not to worry, that well-known purveyor of plastics whose name rhymes with ZAP sells acrylic piping. It's the same material the store-bought gauges are made from. OK, the pipe from RHYMES WITH ZAP has a thinner wall, and it's not graduated, which explains why the commercial ones go so high. I'll grant that the thicker rod stock guages will be sturdier over time, and they're already marked. They're very nice, but come on, twelve bucks?

On the other hand, you can get six feet of 1/4 inch OD, 1/16 inch wall pipe for ONE DOLLAR. Cut it to size, and calibrate to fit your plane. For a dollar, heck, you'll have enough material left over to make a handful of them. If one breaks, there's another ready to go. Give 'em away as stocking stuffers, or use 'em as swizzle sticks. Meanwhile, your friends will have replaced that storebought one at least once because the guy who borrowed it, lost it!

whaddya think. will this work?
blue skies.

[TShort]

Originally Posted by Dan_E_Root

that well-known purveyor of plastics whose name rhymes with ZAP sells acrylic piping.

I need more hints ...

Otherwise, sounds like a good idea!

Thomas

[kevinh]

Originally Posted by TShort

I need more hints ...

Otherwise, sounds like a good idea!

Thomas

TAP Plastics - might not be national, very common over in CA.

[TShort]

Whew! I thought I was missing something really obvious ... never heard of it!

Thanks

Thomas

[markscogg]

I have a 3/8 wood dowel dip stick. It is marked directly with a magic marker.
It gets wet for a few seconds, but 100LL dries before you get to the next tank.

[prkaye]

The dip sticks we use for the Katanas where I fly are wooden dowel, but instead of magic marker, each quarter-tank increment is marked on the dowel with a circular notch cut around the circumference (this way the markings don't wear off over time, and you don't get marker fluid dissolved in your fuel).
The wood gets wet when you dip it, which is what allows you to see how deeply the stick was in the fuel: you read the wet-line relative to the circular notches carved along the stick. Of course, with two tanks to check, this could be a problem unless the wood dries *very* fast. An alternative, perhaps more accurate approach would be to have a separate dip stick calabrated and marked for each fuel tank. Carve the letters "L" and "R" somewhere on the sticks to distinguish them.

[RVbySDI]

Originally Posted by prkaye

An alternative, perhaps more accurate approach would be to have a separate dip stick calabrated and marked for each fuel tank. Carve the letters "L" and "R" somewhere on the sticks to distinguish them.

The wooden stick method sure works for me. Except I do not use a piece of dowel. Instead I use a wooden stir stick I got for free with my paint purchase at the local paint department of the hardware store. The paint department is right next to the aviation department. One of the advantages of the flat stick as opposed to the round dowel is I can calibrate and mark one side of the stick for the L tank and turn it over on the other side where it is calibrated for the R tank. As long as I make sure there is no user error by looking at the wrong side for the wrong tank, I get to use one stick that is calibrated correctly for both tanks. One stick with both tanks calibrated on it saves me from carrying around two sticks.

[Dan_E_Root]

BTW and for the record, during tests at the local chem laboratory in the corner of my garage, I've proven conclusively that polystyrene pipets break down in 91 octane VALERO auto gas. One dip and the degradation begins immediately.

For those who want to more precisely measure tank volume, the dowel is less satisfactory cuz the gas wicks up the stick a little. If you've got a dip tube correctly calibrated you can get precise measurements.

Which begs the question, just how much precision do you need? For me, the question is how much money do I want to throw away? This tube gauge question came about because I didn't see the advantage in a twelve dollar graduated tube, when a stick would do just as well, in my mind. Obviously, there are some who like them, otherwise they wouldn't sell.

I like and use the wooden dowel too. Had a dowel laying around the shop. Pour in five gallons, measure and make a mark. Turn the marks into notches later. Cost me nothing but a little time.

The paint stirrer is an idea I'd not considered, but I like it because it satisfies my frugal tendencies.

cheers.

[prkaye]

>> One stick with both tanks calibrated on it saves me from carrying around two sticks.

except once the stick is wet from dipping in the first tank, how do you see the new wet level after dipping in the second tank?

[Sam Buchanan]

On my RV-6, when I look in the filler and the fuel is just at the bottom of the tank, there is eight gallons in the tank. After you fly your RV for awhile, you will be able to estimate the onboard fuel quite accurately just by eyeballing the tank. But anytime I begin a xcountry leg, the tanks get topped up. For local breakfast runs, I don't launch without 16 gallons in the plane (fuel at least above the bottom of the tanks).

So, all of this is sorta moot if you have a good fuel gauge like the EI unit which is accurate to about a gallon. More and more RVs now have fuel totalizers which adds even more precision to fuel management.

Personally, I have never found the need for a fuel dipstick--Maybe on a C152 where you can't see into the tank, but not on an RV.