Dipsticks

YKA

Pre-takeoff checklist
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Jan 13, 2021
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YKA
Does anyone use a fancy one, or do you all use the 39 cent paint stir sticks from the hardware store, and draw lines on it with a pen like me?

Or maybe you know a 'dipstick ', you know the type of person I mean?

Discuss the dipsticks in your life :)
 
1/4” x 1/2” x 12” piece of table saw scrap, marked with actual gallon values over the course of my first year with the airplane.

39 cents?!? you must be one of those rich pilots!:D
 
I know some geologists that would have trouble finding oil with a dipstick...
 
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I bought a fancy hollow tube thing once for the Cirrus, something like the below but after a few uses it stopped working right.. I'd have the tanks topped off and it would read very low.. at tabs (which in the Cirrus is about 30 gallons) the thing was showing like 16 gallons in the tank. I think the float mechanism developed a leak or something. So I threw it directly in the trash.

I don't get why more planes don't have graduated marks on the "tab" - in the Duchess they have two tabs, one at 30 gallons and the other at 40 gallons.. it's a great idea, probably doesn't cost much, and would be great to just have graduated marks every 5-10 gallons on the thing. +1 for Beechcraft

upload_2021-1-27_18-38-20.png
 
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I calibrated a half inch dowel for the 195. I had a Fuel Hawk when I was flying an Archer.
 
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The Mooney has float gauges in each wing, makes it easy to see how much gas is in there.

upload_2021-1-27_18-46-44.jpeg
 
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I don't get why more planes don't have graduated marks on the "tab" - in the Duchess they have two tabs, one at 30 gallons and the other at 40 gallons.. it's a great idea, probably doesn't cost much, and would be great to just have graduated marks every 5-10 gallons on the thing. +1 for Beechcraft
Skycatcher put holes in the tabs:
  • Gas at bottom of tab = 1/4 tank.
  • Gas at bottom hole = 1/2 tank.
  • Gas at middle hole = 3/4 tank.
  • Gas at top hole = full tank.
  • Gas at the collar = better put a catch basin under the fuel vent.
 
I made aluminum dipsticks for the flight-school airplanes. They were T-shaped, with the cross of the T wide enough that you couldn't lose the stick in the tank, and the T sat on the filler neck so the bottom of the stick didn't quite touch the bottom of the tank. Stuff pounding on the tank bottom, or a rubber bladder, can do damage. I painted them in green epoxy zinc chromate primer. Fuel-proof, and the fuel level shows up nicely on it. With wood you can have fuel wicking up the stick and giving a falsely high reading.

If you calibrate a dipstick, do it right, right from the start. Drain the tanks totally and then pump in the unusable fuel as per TCDS or POH/AFM. Unusable is the difference between the total shown on the filler placard and the amount shown on the fuel selector. The unusable fuel level is the Zero fuel line on the dipstick.

And NO, the unusable fuel is NOT just the fuel in the lines or strainer. It's the fuel that won't reach the tank's outlet in critical attitudes such as a Vx climb or a power-off, full-flap descent. Read the definitions in the link below if you don't believe me. Calibrating a stick with zero-fuel being zero on the stick is dangerous, and I know of an engine failure on approach due to it.

Dipsticks for taildraggers like the 180/185 I also made as Tee sticks, but the shaft had a banana shape that extended some distance back into the tank to reach the lower levels of fuel in the three-point attitude. Again, make it so the stick doesn't rest on the bladder.

Unusable fuel: https://rgl.faa.gov/Regulatory_and_...1F546169B93D7B8385256687006FB8CE?OpenDocument
 
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I've never understood the point of a dipstick. If fuel isn't flowing out artesian style when you remove the gas cap, why would you even want to take off?

(My personal minimum is a five hour reserve.)
 
I've got a high precision wooden ruler with the gals marked on it. Luckily when it got broken the business end was not impacted.

I keep meaning to mark up a high precision wooden dowel, but haven't gotten a round tuit yet.
 
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mine came equipped with metal tab-like thingys in there that tell me when there be zero, 17, or 24 gallons in there.
 
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mine came equipped with metal tab-like thingys in there that tell me when there be zero, 17, or 24 gallons in there.

Mine came equipped with tab things I could care less about, but this one feature... If avgas started to spill on to the wing, you were good to go.
 
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Mine came equipped with tab things I could care less about, but this one feature... If avgas started to spill on to the wing, you were good to go.
“Only time you’ve got too much fuel is when you’re on fire.”

“In Minnesota in January, that might not be all bad, either.”
 
“Only time you’ve got too much fuel is when you’re on fire.”

“In Minnesota in January, that might not be all bad, either.”

Actually, on one memorable BFR, the chief instructor of the flight school asked me, "When have you got too much fuel?"

He had a history. He's like some Gold Seal instructor or something but managed to put a Cessna down on a major street in Sac county since neither he nor the pilot he assisted recognized the lack of fuel in the AC, after an assisted ferry flight.

The Cessna lost its wings. Both pilots were okay. It made the local news and the NTSB database.
 
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Mine came equipped with tab things I could care less about, but this one feature... If avgas started to spill on to the wing, you were good to go.

I use that one the most. It is a very accurate gauge. When blue liquid is running over the white wing... probably are at full fuel for that tank. Probably. Unless you are on a slight hill.
 
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1/4” x 1/2” x 12” piece of table saw scrap, marked with actual gallon values over the course of my first year with the airplane.

I have the same sort of deal, except my stick isn't marked with gallons. A couple notches at 5 gallon intervals, full tank notch in the middle, then mirror image notches for the rest of the stick's length, making it exactly twice as long as it needs to be. That way I don't have to worry about which end I stick in the tank, and, being long, it's virtually impossible to lose it by accidently dropping it in there.

Tim
 
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That has moving parts. Things can go wrong.

While it's true it can go wrong, in the 13 years we've owned the plane they've worked well and have remained accurate. We leave the plane filled to the tabs (25g/side, max is 32g/side), and when filled to the tabs the float gauges read 25g on the dot. Interestingly though, one can't directly correlate to the electric fuel gauges on the panel as Mooney decided to have the fuel gauges read in pounds. Yes, one can do the conversion, but I consider it interesting that the inside gauges are in pounds.
 
While it's true it can go wrong, in the 13 years we've owned the plane they've worked well and have remained accurate. We leave the plane filled to the tabs (25g/side, max is 32g/side), and when filled to the tabs the float gauges read 25g on the dot. Interestingly though, one can't directly correlate to the electric fuel gauges on the panel as Mooney decided to have the fuel gauges read in pounds. Yes, one can do the conversion, but I consider it interesting that the inside gauges are in pounds.

Never heard of the pounds thing in little airplanes but then I haven’t flown very many different ones. Do you open the cap and have a peek inside to make sure that wing thingy didn’t get stuck. It’s not a chance I would take
 
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Never heard of the pounds thing in little airplanes but then I haven’t flown very many different ones. Do you open the cap and have a peek inside to make sure that wing thingy didn’t get stuck. It’s not a chance I would take

Yes, I always put eyeballs on the fuel level during pre-flight. Quick pic of the fuel gauges on the panel:

Capture.JPG
 
I'm not a fan of trusting any fuel gauges, dipping the tanks is how I do it.
 
"When have you got too much fuel?"

When you are on fire is probably the answer he was looking for.

When you have 5 hours fuel for a 1 hour trip and have to displace revenue because of the gas. Or count the extra fuel as ''pocket gas''....
 
When you are on fire is probably the answer he was looking for.

When you have 5 hours fuel for a 1 hour trip and have to displace revenue because of the gas. Or count the extra fuel as ''pocket gas''....
Besides that, there are plenty of airplanes in which you can fill the seats, or fill the tanks, but not both. Four hour's fuel for a one-hour flight is also wasting performance hauling all the extra weight around. It can mess up plans to land and take off at some shorter strip.

At the flight school I had a tank set up next to the fuel pumps for extracting fuel from the airplanes. Besides being handy for emptying the tanks for maintenance, it allowed us to remove fuel after someone filled the tanks and made the next flight impossible because more people or gear had to go on board.

That tank's system was plumbed so that extracted fuel went directly into it, and fuel pumped out of it ran through an expensive waterstop filter that totally cleaned it.
 
I marked my own on a maple stick I made. I trust it preflight and a FS-450 in flight. My digital fuel gauges are along for the ride.
 
The club rules are if you flew it more than 1 hour, put it away full. I look at both tanks as part of my pre-flight. Eyeball says full? All is well. I have never dipped a tank in 20+ years.
 
I dip the tanks before every flight (taildragger, gauge doesn't work on the ground) and before fueling so I know how much to add without overflowing (can't see into the tank as it's in the top wing center section). In flight, the gauge doesn't register less than 6 gallons.
 
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