The International Cessna 170 Association

I seem to recall reading a recommendation for a fuel dipstick for 170s that involved cutting off the bottom end at the zero mark.
I see Spruce sells these: FUELHAWK CESSNA 172 19 GALLON FUEL GAUGE Has anybody tried one of these for the 170?

It is a Fuelhawk that you cut off. But not sure if it's that model. There is no Fuelhak made specifically for the 170.

George Horn recommended these dipsticks here: http://www.cessna170.org/forums/viewtop ... ck#p111915

I made one by draining the fuel from one tank, putting five gallons in at a time, and marking the stick each time. Made “T” handle at top so it can’t drop into tank.

The fuel hawk dipstick I asked about is the same one George Horn recommended in that link mentioned by lowNslow, only the price has increased by
about 30%. Apparently cutting it off at the zero mark compensates for the 170's 3 point attitude.

The variable with any fuel stick and any tank, is the angle one “sticks” the tank. I do not recall George’s instructions but seem to remember he put it against the rib at the bottom of A and B tanks. I did this and fell the cut off version work relatively well. Easy to ready if you can hold your thumb/finger over the tip to hold suction. A plain marked stick can work as well. For the ‘48 owners, I’m not sure George’s instructions apply with a Fuelhawk.

I read Georges post on this, early in my ownership, and have used the dipstick as he outlined in his directions since then. I have found it to be accurate enough as well, and can recommend it without hesitation.

I have the A model, and as George states, it works fine.

Directly below the fuel cap opening is a stiffener/baffle which runs along the bottom of the tank left/right. Placing the Fuel Hawk into the filler-opening at the rear of the opening, one can move the bottom of the Fuel Hawk AFT along the bottom of the tank until it contacts that stiffener at the bottom of the tank. This will provide an accurate and repeatable sampling of the fuel level using the modified Fuel Hawk for a 19 gal 172 cut-off at the "0" maker.

I used this method and found it very accurate at lower quantities but when the tank is full I get readings well above the 19 gallon mark...must be doing something wrong?

Thanks for any suggestions...

Bob

rnealon1 wrote:I used this method and found it very accurate at lower quantities but when the tank is full I get readings well above the 19 gallon mark...must be doing something wrong?

Thanks for any suggestions...

Bob

The tank does hold 21 gallons, and in level flight will use significantly more than the 18.5 stated in the AFM.

Realizing that fuel pumps, whether on a fuel truck or at the fbo, are subject to some minor errors, has anyone had a fuel tank completely empty and checked to see exactly how much fuel you can put in your tanks? Several years ago I had an occasion to remove both my fuel tanks, then filled them from a truck and found I could only get 19.6 gallons in one tank (left I believe) and 19.7 in the other one. Prior to that time by a couple of years I drained the left tank by removing the sump drain and again got 19.6 gallons in it. Just curious.

They used to sell an uncalibrated dipstick marked 0-10 which you calibrate yourself and record the info on the supplied calibration chart. I used one on my C180 and cross-referenced it with my fuel gauges. Pretty interesting results. The gauges were wrong at almost every quantity but they were very repeatable when checked over time.

After some experimentation I discovered that a C-172 “FuelHawk” for a 19-gallon 172 was a great dip-tube if the tube was cut at the “zero” mark. (The FuelHawk has a marked section of two gals of unusable fuel below the “0” which, if cut the area off below the “0”, is perfectly calibrated for a 170 A or B.)

The method used with such a modified FuelHawk is to insert it into the filler-neck, resting the lower end at the mid-tank bulkhead, and it will read accurately. (The mid-tank bulk head can be easily located by inserting the tube to the bottom of the tank, then dragging the lower end aft toward the trailing edge of the wing until it contacts the bulkhead which is easily noticed by any further movement aft being blocked.)

I’ve done this and repeatedly check accuracy from empty to full and found it perfectly calibrated.

After some experimentation I discovered that a C-172 “FuelHawk” for a 19-gallon 172 was a great dip-tube if the tube was cut at the “zero” mark. (The FuelHawk has a marked section of two gals of unusable fuel below the “0” which, if cut the area off below the “0”, is perfectly calibrated for a 170 A or B.)

The method used with such a modified FuelHawk is to insert it into the filler-neck, resting the lower end at the mid-tank bulkhead, and it will read accurately. (The mid-tank bulk head can be easily located by inserting the tube to the bottom of the tank, then dragging the lower end aft toward the trailing edge of the wing until it contacts the bulkhead which is easily noticed by any further movement aft being blocked.)

I’ve done this and repeatedly check accuracy from empty to full and found it perfectly calibrated.

19 gal 172 FuelHawk, Aircraft Spruce PN 13-00442
Remember, cut it off at the “zero” mark to modify it for a 170 A or B.

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