Altimeter Calibration Height

Stefan wrote:
Steven P. McNicoll schrieb:

The static lines are vented to the atmosphere, so the change in pressure
with altitude takes place in the static lines just as it does in the
atmosphere.
The pressure in the three altimeter cases is the same, so the indicated
altitude is the same.

Ever heard of Kollman?

No, is he any relation to Kollsman?

Matt

Jose wrote:
I'd have to do it in a vacuum to eliminate the drag force.

Huh? Drag force isn't logical. It is an empirical observation.

Sure it is. You are moving one thing through another thing. It is
quite logical that the thing you are moving through is going to be
unhappy about that and resist your motion! :-)

Matt

"Matt Whiting" wrote in message
...

No, it indicates a pressure differential at the level of the instrument.


Show me an altimeter that indicates in units of pressure.

Steven P. McNicoll wrote:
"Matt Whiting" wrote in message
...
No, it indicates a pressure differential at the level of the instrument.


Show me an altimeter that indicates in units of pressure.

Show me one that indicates in units of "altitude at the level of the
instrument."

"Matt Whiting" wrote in message
...

Show me one that indicates in units of "altitude at the level of the
instrument."


http://www.auf.asn.au/groundschool/altimeter1.jpg

Steven P. McNicoll wrote:
"Matt Whiting" wrote in message
...
Show me one that indicates in units of "altitude at the level of the
instrument."


http://www.auf.asn.au/groundschool/altimeter1.jpg



Try again. It is adjustable so I can make it read any altitude I like.

Honestly, I don't know how you guys got Newton involved.

How about a (better) hypothetical?

The imaginary aircraft is sitting at Imaginary Airfield (KIMG), which
sits at a billiards-table-flat 50 MSL. The aircraft's static port is
mounted at the centerline of the fuselage, which is 10 feet from the
ground. The instrument in question is mounted 4 feet above the centerline.

What will the gauge read when set to the proper barometric scale? 50,
60, or 64 feet?

TheSmokingGnu

TheSmokingGnu wrote:
Honestly, I don't know how you guys got Newton involved.

How about a (better) hypothetical?

The imaginary aircraft is sitting at Imaginary Airfield (KIMG), which
sits at a billiards-table-flat 50 MSL. The aircraft's static port is
mounted at the centerline of the fuselage, which is 10 feet from the
ground. The instrument in question is mounted 4 feet above the centerline.

What will the gauge read when set to the proper barometric scale? 50,
60, or 64 feet?

Not enough potential aswers, you for got:

Under IFR

Under VFR

Pass Go and collect $200

No one is going to tell me how to set my altimeter

--
Jim Pennino

Remove .spam.sux to reply.

What will the gauge read when set to the proper barometric scale? 50, 60, or 64 feet?

That depends on what the people in the calibration shop did to it. My
understanding is that the =installation= is certified. It would be
logical for the certified installation to be calibrated to the wheel
height. It would be equally logical for it to be certified to the
instrument height.

It's an FAA certification. 'nuf said.

Jose
--
Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

Recently, Steven P. McNicoll posted:

"Neil Gould" wrote in message
et...

Perhaps you misunderstood Jose's example, but I believe he's correct;
while an altimeter senses the pressure at the level of the
insturment, it *indicates* the calibration set by either the shop
(e.g. compensating for the altitude of the installation) or the
pilot via the Kollsman window.


I understood it, I didn't say he was wrong.

Perhaps I misunderstood your response.

Jose stated:
[...] An altimeter indicates whatever it is set to indicate.
[...]

and:
If you don't get an altimeter setting, you will (likely) set the
altimeter so that the hands indicate the airport elevation as
indicated on your charts, even though you and the instrument are a
hundred feet higher.

If you do get an altimeter setting, you'll set it for that. Then the
question becomes (since the altimeter doesn't know that it's in a
tall airplane) whether, at calibration in the shop, it was set to
indicate actual instrument altitude or to indicate something else
(like instrument altitude minus a hundred feet).
[...]

To which you replied:

In other words, an altimeter indicates altitude at the level of the
instrument itself.

How do you reconcile your comment against Jose's statements? Both
statements will only be true under a very limited set of circumstances
that I would think excludes "In other words...".

Neil