What is this airline thingy?

On Friday, October 11, 2019 at 2:07:11 PM UTC-4, Tango Eight wrote:
I don't think it's a netto leak. I've made a few of those.
IIRC the tube ended up about 3.5 - 4" long, 0.012" ID.

I think you're right, trying to recall last time I saw one decades ago...
Don't know why a restrictor would be that long though.

Side note: modern pressure transducer based electronic varios like to be
on pneumatic circuits without leaks, without large capacities and without
any flows to speak of. Sharing a TE probe with one (and only one)
mechanical vario may be done with reduced performance of the electronic
vario. Sharing static with any mechanical instrument generally goes bad,
don't do it. Sharing the pitot with one ASI can be done in a pinch,
it is the least critical of the three.

Any mechanicals on pitot, static or TE will definitely upset the SN10C...

Regarding the problems arising from sharing pitot, static, and TE across mechanical and transducer-based instruments:

I can see why the flow generated by anything using a capacity would be large enough to cause trouble. My gut feeling is that flow into or out of an altimeter or a mechanical ASI would be too small to matter.

If these instruments are impactful, what’s a workaround for a situation where finding truly separate pitot and static sources for the mechanical instruments is impractical? I’ve seen experimental gliders with digital altimeters, but I suspect a TSO’d option would be hard to come by, and I don’t think I’ve ever seen a (modern) sailplane without a mechanical ASI.

Would T’ing off static and pitot lines somewhat further than the traditional 6 inches from the instruments do enough to mitigate the effects?

Genuinely curious about this.

Neiman

On Saturday, October 12, 2019 at 10:18:14 PM UTC-4, wrote:
Regarding the problems arising from sharing pitot, static, and TE across mechanical and transducer-based instruments:

I can see why the flow generated by anything using a capacity would be large enough to cause trouble. My gut feeling is that flow into or out of an altimeter or a mechanical ASI would be too small to matter.

If these instruments are impactful, what’s a workaround for a situation where finding truly separate pitot and static sources for the mechanical instruments is impractical? I’ve seen experimental gliders with digital altimeters, but I suspect a TSO’d option would be hard to come by, and I don’t think I’ve ever seen a (modern) sailplane without a mechanical ASI.

Would T’ing off static and pitot lines somewhat further than the traditional 6 inches from the instruments do enough to mitigate the effects?

Genuinely curious about this.

Neiman

If you want good instrumentation, it starts with good sources. Fin mount triple probe is the reliable standard for vario sources. Use the nose pitot and side statics for basic instruments (as usually specified by the manufacturer).

T8