REFLECTOR: Pressure testing

[David Staten]

Math time.

1 PSI is overkill. Even Half a PSI is too much. A water manometer to 
handle 1 psi would need to be nearly 4 feet tall.  If you can make a 
water manometer that can accurately measure something on the order of 12 
INCHES of water pressure, and HOLD that water pressure for hours and 
days, you can establish the presence or absence of a leak. Fuel tanks in 
these planes are just not meant to hold pressure.

Dave


Keith Hallsten wrote:

>David,
>
>1.5 psi is definitely overkill.  You just want enough pressure to determine
>whether or not you have a leak, not enough to blow the strake apart or CAUSE
>a leak.  One-half of a psi is plenty.  Remember, fuel has a higher viscosity
>than air, so a little pressure on the air is enough to determine whether or
>not the fuel will leak.  Thus, there's no need for the 5-gallon bucket, and
>a few inches of water column is sufficient. 
>
>I did my "pressure" testing with a large, high-quality latex party balloon.
>Not a calibrated instrument, but if the balloon stays inflated for a couple
>of days, you know there's no leak.
>
>Keith Hallsten
>
>
>  
>