I bet you all thought I’d run out of silly questions. I think I’m likely to keep coming up with them as long as I live. Today’s stupid question is why there is always unsuable fuel capacity in the tank? My theory is that it’s a hangover from the days when the cleanliness of the fuel was less certain than it is now. The idea being that the sump gave them a better chance of preventing debris from entering the fuel lines. Of course I may be wrong as usual.
By: Moggy C - 26th June 2013 at 17:41
It was actually the picture of the PA28 tank that misled me. I have run those dry in flight also.
Apologies.
Moggy
By: mike currill - 25th June 2013 at 23:42
It’s OK Tony I think Moggy was nit picking, I know enough to know that fuel systems very from type to type and often between models of the same type. I don’t think I’ll be intentionally running to dry tanks on the Eurostar as I won’t have another one to switch to.
By: TonyT - 25th June 2013 at 17:58
One was taking in context to a Cessna 152 when one said that in which the tanks are interconnected and only have a single selector for off and on 🙂
One should have made that clearer…… My faux pas.
By: Moggy C - 25th June 2013 at 15:08
… if you have got to the point of drawing that low from the tank your on the way to the crash site.
I don’t follow this.
On the PA22 we regularly ran one of the tanks dry in flight before switching over. It gave us a real-world measure of maximum endurance under the flying conditions on that day, thus enabling us to calculate sensible endurance with 20 minutes reserve with some confidence.
Moggy
The rest was spot-on
By: TonyT - 25th June 2013 at 12:22
A bit more for you.. this is a 152 fuel tank
Top right you can just see the feed connection which is on the lower edge of the tank, bottom right is the vent line connection at the top which connects to the other tank and below that the crossfeed line, again on the lower side, that balances the tank contents out with the other side. Big hole is the cap, little hole the fuel sender mount. The vent line connect both as originally only the port side was vented, now both caps are as a added safety measure.
The two lines on the tank are where it is strapped into the wing, the panel goes over the top and is screwed to the wing and the filler attachment.
Bottom picture
This is a PA28 tank, they are metal and are a part of the wing simply screwed on, the supply comes out the inboard side, on the rear is the sender and the vent line, that vents overboard, there is no cross connection between wings as the tanks are selectable, unlike the 152 where its all or nought. Caps are also vented.
By: mike currill - 22nd June 2013 at 06:14
Thanks Tony that’s answer my query quite well. I’d never thought about the fact that the feed came from the side of the tank.
By: TonyT - 21st June 2013 at 21:37
Because a fuel feed pipe out of a tank on the likes of your Cessna or Piper etc has to feed out of the side, you couldn’t feed it vertically down as it would stick out of the bottom of the wing, if you made the tank so the pipe could come out of the bottom internally then you would waste 1/2 of the space available for the tank and hence lose half of your fuel load. And if you think you could put the outlet at the very bottom and wrap it around the side, well the fittings need to screw onto that, so you need skin clearance for those too and by the fact it screws into the tank also creates a step from the bottom. Crap and water can come into it, but to be honest if you have got to the point of drawing that low from the tank your on the way to the crash site.
By: nostalgair2 - 21st June 2013 at 16:28
I think that absolutely nob on!
Sign In
June 21, 2013 at 2:28 pm