What's this?

[SixPapaCharlie]

 

[nauga]

Homemade vent/fuel cap cover on a Luscombe.

Nauga,
and an old hangar mate

 

[LauraE51]

An empty two liter bottle after the diet coke and mentos have emptied out into the tank?

 

[timwinters]

what's this?

Could you get another photo oriented slightly to the right? I can't quite make out the FAA part number in this one.

 

[Fearless Tower]

Why would you need that inside the hangar? Are they worried the temp will rise and fuel will burp out the vent?

 

[MyassisDragon]

Homemade vent/fuel cap cover on a Luscombe.

Nauga,
and an old hangar mate

Thats my guess too. you can see the tall vent tube inside the bottle.

Interesting article I found when googling Luscomb fuel vent.
http://www.aero-news.net/index.cfm?do=main.textpost&id=d3de2e27-8dab-423d-a810-6035a45a804d