Help Please on How this Fuel Gauge Works

Milton Shupe

Milton Shupe

Staff Contributor
Staff member
This is the best picture I have on an underwing fuel gauge for the Puss Moth.

It is not clear exactly how this works. Is it simply a fuel bowl with a readable level? Or is there some sort of float in it? Does anyone have a working knowledge of what these are supposed to look like, how they work, and if there are typically markings on the new ones?

Thanks
 
Not sure about the Puss Moth, but if it's anything like the Stearman - which has the fuel sight gauge under the tank - there's a float that slides up and down the tube depending on the fuel level.

Pete.
 
Having never seen a Stearman or Puss Moth, I can only hazard a guess....from the looks of it, I would say it has a float (probably red). My grandpa had a fuel tank on his land back when he ran a dozer and did construction. The gauge for that tank was a very large metal and glass cylinder with a red float inside of it. The more fuel was in the tank, the more pressure was exerted within the gauge, the higher the float went up the glass. There were recessed markings in the glass, painted in with black paint, that told the number of gallons of fuel in the tank. It was a very large tank, bigger than a four door sedan of the period (early 70s)...probably a 1000 gallons.

OBIO
 
Ya know, the more I look at that dohickey sticking out the bottom of that wing...the more I am thinking that it isn't a fuel gauge at all. I know that on early planes, they had water traps that had to be drained before each flight. I'm more inclined to think that that is what the thingimajig actually is. It has a fitting to allow drainage. The window would allow the pilot to see if there were any water that needed to be drained from the tank.

OBIO
 
Hi

Seem's to me to be a greasing point !!
It's seem's to be a grease nipple (teflon on the thread) under the red thinghy :) (Stauffer type)
Anyways it is .. strange those things are not secured
 
OBIO said:
Ya know, the more I look at that. It has a fitting to allow drainage. The window would allow the pilot to see if there were any water that needed to be drained from the tank.

OBIO
Click to expand...


That was my first guess. I just never said anything.
 
I looked at this last night and I also thought it could be a water drain. That should not stop it from being a float gauge either.

If it is a fuel gauge then it must be set up something like my crude drawings below.

Figure one would not make sense but would work. The tank would be empty when the indicator is at the top of the gauge.

Figure two would make more sense as the tank would be empty when the indicator is at the bottom of the gauge.

It is likely that the distance to fulcrum or indicator arm (A) is much longer than the distance on (B) so that the indicators length of travel is shorter. This would keep the gauge as small as possible. From the picture I don't see this protruding below the wing any more than 4 to 6 inches but I could be wrong.

Either way I think creative license is warranted here.
 
Milton,
I know a Guy who has both a Gypsy and Tiger Moth. Let me see what he has to say. I'm not sure if the the fuel system is the same as the Puss, but like most buiders- Once they have something that works, they dont like to change it.
As a Side Note Milton, This research and attention to detail is what puts your airplanes and many developers like you a step ahead of the pack. And now that I have my soapbox out. Thats what great about the whole sim community. People helping people. Thanks for all your hard work.:ernae:
 
Thanks for the assistance, opinions and comments from everyone.

I can affirm now that the underwing device in the initial pictured post is a fuel gauge from an article I have from FLIGHT InternationaL, 25 December 1975.


Here is an excerpt:

"We checked the red tabs at each wing root to confirm that the folding wings were safely locked in place and looked at the glass-bowl fuel indicators beneath each wing."

Scott has started development of a best-guess functioning gauge that looks like the attached. It is apparent that the glass enclosed gauge has glass on each side of the housing so the same unit can be used on either side of the craft.

I would also guess that the drain at the base is there to remove any sediment or water build-up that occurs over time.
 
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