The International Cessna^® 170 Association

rnealon1 wrote:Hi George,

I am using the Fuel Hawk dipstick cut off at the 0 mark as you described. What I note is that when the tanks are full (bottom of the filler neck) I read approximately 22 gallons on the stick.

At lower levels I measured 9 gallons each side, then filled the tanks with a total of 19.2 gallons. This made perfect sense for a total of 37 gallons usable, but the stick then measured well above as described.

Thanks,

Bob

The FuelHawk dipstick is only calibrated/inscribed to 19 gals,...so any level you observe above that is to be ignored due to tank/filler-neck narrowing-shape unduly influencing the level in the tube. (If a FuelHawk that is inscribed more than 19 gals is used it is not the model I recommend.)

Addendum: The modification of the FuelHawk I recommend was developed by me after careful experimentation. I first drained my two gallon error on the high side. By cutting the bottom of the FuelHawk off at the “zero” mark, the error was eliminated resulting in accurate fuel level indications inside the tube at each graduation... until the tank is full at 19.5 gals. (Continuing to add fuel into the filler neck area is only a few ounces but results in a higher than actual impression.)

It’s important when inserting the FuelHawk to keep it at the rear of the filler-neck, and the bottom of the tube placed at the bottom of the tank, and as “aft” as possible...which will be found to be adjacent to a span-wise baffle inside the tank just below the filler neck.

I have been using the Fuelhawk tubes such as George has outlined for the last 4 years, and found them to be very accurate. Fuel burn per flight hour corresponds well with the tubes after flying.

As he stated, if you fill to the necks it will show above the top mark, but I'm not worried about fuel levels when I know I am full. It's when I'm flying at lesser fuel loads that I want the accuracy, and these work very well with that.

Hi All,

Thank you for the clarifications. The model I am using is only calibrated to 19 gallons as George mentions, I was "interpolating", or rather "extrapolating" above 19 gallon reading when full.

At lower levels I found it accurate as described using the aft edge of filler neck and aft against the baffle.

Thanks again,

Bob

Addt’l info for those contemplating getting a FuelHawk for a 19 gal C-172 and modifying it:

Cut the tube off at the “0” mark using a tubing cutter, then polish the cut edge on a wire-wheel to prevent any tendency for cracks to develop from that sharp edge.

I just received the 19 gal 172 Fuelhawk dipstick and modified it per the instructions from gahorn. I thought I would post some pictures just as a reference. I haven't tried it yet, but looking forward to using it. (by the way, if I modified it incorrectly, let me know and I will remove this post).

Doug

I “had”one but it fell off the wing on to the concrete and shattered into 3 pieces. Then throwing it in the bin ,my hand hit the side of the bin and cut my hand with the broken pieces of the tube .

ghostflyer wrote:I “had”one but it fell off the wing on to the concrete and shattered into 3 pieces. Then throwing it in the bin ,my hand hit the side of the bin and cut my hand with the broken pieces of the tube .

Aussies use Imperial measure litres/gallons anyway, right?