Making a Fuel Dipstick

[StudentPilot]

I just got a plane that did not come with a dipstick. I drained the last 8 gallons of fuel from the engine drain (ie including some fuel not in the tanks and at the time thinking it would not drain the unusable fuel). The tanks are 40 gallons total capacity, 37 gallons usable, and I put 40.2 gallons back into the tank. I had started off marking my new dipstick in 5 gallon increments, but now I am thinking I had drained most/all of the unusable fuel from the tanks. Should the first marking on the dipstick be 2 gallons or 5 gallons?

[old_man]

...........and I put 40.2 gallons back into the tank. I had started off marking my new dipstick in 5 gallon increments,

Your methodology is flawed. I doubt most tanks are linear for depth vs volume. You should have put in 5 gal at a time and marked it off that way.

That being said I don't think making your own dipstick is the best (or legal) idea but I really don't know about that one. I am no expert.

[photofly]

Some are more linear than others. This one isn't, very:


This one, maybe more so:

[ahramin]

Empty weight includes unusable fuel. Your dipstick should read 0 with the first 2 gallons in. The next 5 would be 5, and so on. Makes the math easy when doing your weight and balance.

Make sure your aircraft is sitting in its normal attitude when you make your dipstick. If it was sitting tail low when you made your dipstick and then you climb on the wing to check and your weight pulls the nose down, your dipstick will way overread.

[ScudRunner]

Here's a pro tip: trace the dip stick on the inside of the logbook or something that you will normally have with the plane. When you loose the stick and you will you can grab a willow or whatever you can find out in the bush and mark off some lines on it with your leatherman and vola instant dipstick.

[StudentPilot]

To clarify, I marked the dipstick as I went along.

Thanks . and Ahramin.

[ipilot54]

I think Air Canada has a dipstick you can have. I heard it comes with a metric conversion chart as well.

[AirFrame]

I made my own dipstick as well... My tanks are very linear once you get about 20 litres in. I think 12 is where it hits the bottom of the dipstick. Since it takes 72 litres a side, I marked it in 10L increments from 22 to 72. Then I repeated it on the other side, and confirmed my measurements were accurate on the first side.

I recorded the measurements along the stick so I wouldn't have to do it again later. But I also made a second stick as backup...