Capacity flask tube length

[dbrunone]

I'm considering relocating my 0.45L capacity flask (for the vario) from behind the instrument panel to elsewhere in the cockpit. I would have to use maybe 6 or 7 feet of tubing to do that though...by some quick calculations, the extra tubing will make the 0.45L flask effectively almost 0.50L. Would this throw off my vario too much, or will it matter? Thanks

[Peter Scholz[_3_]]

Am 15.11.2012 12:28, dbrunone wrote:
> I'm considering relocating my 0.45L capacity flask (for the vario) from
> behind the instrument panel to elsewhere in the cockpit. I would have to
> use maybe 6 or 7 feet of tubing to do that though...by some quick
> calculations, the extra tubing will make the 0.45L flask effectively
> almost 0.50L. Would this throw off my vario too much, or will it matter?
> Thanks
>

you could reduce the volume of the flask to compensate, e.g. by putting
an adequately sized block of styrofoam into the flask.
--
Peter Scholz
ASW24 JE

[John Galloway[_1_]]

At 14:11 15 November 2012, Peter Scholz wrote:
>Am 15.11.2012 12:28, dbrunone wrote:
>> I'm considering relocating my 0.45L capacity flask (for
the vario) from
>> behind the instrument panel to elsewhere in the
cockpit. I would have to
>> use maybe 6 or 7 feet of tubing to do that though...by
some quick
>> calculations, the extra tubing will make the 0.45L flask
effectively
>> almost 0.50L. Would this throw off my vario too much,
or will it matter?
>> Thanks
>>
>
>you could reduce the volume of the flask to compensate,
e.g. by putting
>an adequately sized block of styrofoam into the flask.
>--
>Peter Scholz
>ASW24 JE
>
If it is a Winter flask I don't think it would be possible to
get the styrofoam in there.

A practical experiment with a 65" length of standard
instrument tubing, a measuring jar and water gives an
internal capacity of 29.7 mls for a 7 foot length. That
would add 6.6% to your capacity so all reading up and
down would be increased by that same amount. A 6 knot
thermal would read 6.4 knots. That wouldn't worry me.
The zero would remain the same. I would be more
concerned about making sure the tubing is fully supported
throughout its length.

John Galloway

[Chip Bearden[_2_]]

Time for another "in the old days" story. :) Many years ago when
diaphragm or bellows TE compensation was common (e.g., PZL,
Schuemann), tuning the capacity of the bottle and tubing to the
compensator was necessary. I had a Schuemann TE/netto compensator that
I loved, but had to mount it behind the cockpit. Since it incorporated
a .45l flask, I used much smaller diameter tubing to run to the vario
(no problems with delays). Others who had room to mount the
compensator near the vario would coil up many feet of the standard
instrument tubing to add capacity. The amount by which all of this
affected the accuracy of the vario was insignificant compared with the
effect on TE compensation. That's no longer an issue with TE probes so
I doubt you will be able to see any difference.

Chip Bearden
ASW 24 "JB"
USA