Fuel dip stick C172
 

Can anyone help me make a fuel dipstick for a C172 with standard 20 g tanks? I really just want a piece of wood with graduations on it, innit. Anyone help?

Empty the tanks. Get a broom handle. Add 1 gallon incrments. Mark each time. Job done, innit?

What he said.

Or just order a "fuel hawk"

FUELHAWK CESSNA-172FUEL GAUGE from Aircraft Spruce

http://www.aircraftspruce.com/catalo...s/13-00442.jpg

don't forget to order the device for fishing plastic fuel sticks out of the tanks

Fuel dip stick C172
 

Alternatively, you could do this:
Go to your local hardware and grab a suitable piece of timber. I use 2" cover strip it's profile is flat with rounded edges- I find it stows well and easy to mark graduations. Make sure it's long enough to not fall into the tank if you accidentally let go. When the aircraft is reasonably low in fuel take your dipstick and aircraft to the bowser. Place the dip stick into the tank, remove it and mark the line made by the fuel. Don't let it sit for too long as it draws fuel up the timber. Add 5 litres, dip and mark again, repeat this process until the tank is full. The last addition may be less than the 5 litres, but note the amount. The "high tide mark is obviously full, so mark it with the total useable for that tank, the next Mark down will be a quantity equal to full, less the last odd amount added. Now label the remainder of the marks progressively deducting 5 litres. I've made at least 30 dipsticks this way over the years and found them to be sufficiently accurate and saves draining a tank. Also not a bad idea to crest a template on cardboard or paper and store it away in case the original goes missing. I lost one out of a Piper Dakota 15 years ago and recently located it in the baggage compartment of a Tiger Moth when checking a guy out in it. Someone had "borrowed" the dipstick to I've the Tiger mag a tap to release the impulse coupling.

Forget the plastic thing.

Calibrate a piece of wood as said above but don't forget, on a 172, to set the fuel tank selector to anything but 'BOTH' otherwise the tanks will crossfeed while you fill and give an innacurate calibration.


7700

A wooden spoon is great for this. The thin bit dips the tank and the fat bit won't fit through the hole so it can't fall in.

they also crossfeed in the off position......tape a stick across the dipstick to stop it dropping in the tank.....it is as close to religion as I dare get!

DIPSTICK
 

Uhhh
Someone want me?

Ah, well what a bunch of helpful clever dicks. We have wooden spoons, broom handles, plastic tubes floating round in tanks, an enlightening but irrelevant tangent about cross-feeding and ... a Dipstick from Hong Kong (where the best dipsticks come from). I was rather hoping someone knew the distances between the marks on a bit of wood and would tell me so I can make one.

Ooo, I wouldn't touch that with a ten foot dipstick! Pilot runs out of fuel - investigators ask: "How'd you know how much fuel you thought you were carrying?". Pilot answers: "I made a home made dipstick with dimensions I read on an internet chat group, from a person I do not know, for a model of 172 I could not confirm."

Best to make your own. Don't do it with the fuel selector to "both" or "off", and assure that the plane is sitting repeatably level, as that makes quite a difference in the reading. Cut the notches in the handle of the spoon, rather than ink, which will wash off.

There is, of course, one flaw in all these good ideas. They assume the plane is on flat ground! At Elstree that is rarely the case (both Echo and Bravo are on a slope), so always err on the side of caution.

It's also worth mentioning that, while the assumption of a linear relation between the dipstick scale and the full quantity might be just about OK for a C172, it's dangerous to generalize. Doesn't work in a P2002, for example. But you can get closer to the truth by running the tank very low or dry, then adding known fuel quantities and noting the levels on a ruler until you hit full. A little bit of graph plotting then gets you the curve you need to make the dipstick.

I agree with Step Turn in that I would never trust a dipstick that I hadn't personally made or checked.

By the way, you'd be surprised at the difference you see between two notionally identical tanks (e.g. LH or RH) when you do the plotting exercise for some aircraft.

Which tank is on the caution side? :)

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I'll be off now.

That would still result in a better degree of accuracy than the installed fuel gauges I suspect ;)

WWC - why was mention of cross feeding whilst trying to calibrate a dipstick 'irrelevent'?
If you're filling at 5ltr measures and one litre or more is cross feeding in to the other tank, what will that do for dipstick accuracy?

I think we all know who's the dipstick if they can't work out how to make and calibrate a dipstick.


7700

It's in the middle isn't it?

I use the exact one pictured by James.
Not a fan of the wooden ones for a couple of reasons:

some bright spark at the flight school I rent from made a whole load from a wood of such a shade that it barely changes hue when the fuel touches it, rendering it near useless. Personally I feel it must have taken a lot of talent to find a wood with these properties and secondly despite having the aircraft reg sharpie markered on them, I keep finding dip sticks for the 152s in the 172s.

Not helpful.

The dipstick itself is marginally more accurate than the gauges. I really just use it to check that we are all in agreement within a quarter of a tank or so, as I don't tend to do long flights that are fuel critical. At least the dipstick doesn't go below zero if someone overfills the tanks as the gauges on one 172 I fly do :confused:

FWIW.

I made a wooden dipstick long enough not to tilt/fall into my Rans S6 wing tanks.
I paint mine with gloss black paint. Then the fuel wetting shows up clearly, but quickly dries off again as it doesn't soak into the wood, so repeat depth checks are easy.

The S6 tanks when filling have different cross sectional areas as they approximate to the wing profile, so for me the best setting up method has to be fill and mark in 5 litre steps. It's now served me safely for 1/2 dozen years

mike hallam

squawking 7700 - I may be a dipstick but you're an Ignorak (ignorant Anorak). Thank you Round Sounds.