Barometer in a sealed airframe


Will a Barometer work in an air sealed airframe ?
If not, what other reliable all weather methods exist for altitude measurement ?

Completely sealing a fuselage is poor practice. You’ll induce stress as pressure changes with altitude. Provide some static ports/weep holes, and a barometer inside should function well.

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No. Take Yuri’s advice or use an external barometer which perhaps you can protect w/o sealing as they are small boards.

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Wouldn’t water poor in through the static ports/weep holes ?

Not if you locate them well. It’s not a submarine, after all.

I would be very surprised if you had a truly sealed fuselage. It would be very difficult to do, if it was ‘almost’ sealed the result would be accurate barometer readings just with some lagging upon altitude changes but i don’t think any fuselage would be sealed well enough to cause this at all.
Even a simple 2-3mm hole on the tail section would be plenty to keep the pressures balanced and would not cause any water ingress issues


Well…I do want it to be able to float over water for long durations.

Sure, but that doesn’t mean you will get it completely airtight.

I’m aiming towards IPX7 - so it would be water tight. I don’t see how it can meet this standard while having 1mm holes in the structure.

And even it was possible as you said - there will be a delay until the pressure stabilizes,won’t this delay cause poor altitude hold ?

You can explore GPS or a rangefinder as the altitude source(s), but those both have inherent drawbacks, as well (you’ll find plenty of topics on those subjects).

Additionally, you’ll likely need to plan for some method of cooling/heatsinking to prevent hardware overheating.

It’s not even worth worrying about baro inaccuracies due to delays in pressure equalization. Either build with a barometer in mind or don’t.

To simply answer your first question: a barometer will not function at all in a perfectly sealed hull.


Get a barometer with a tubed pressure port and route that to a static port on the side of the vessel. That way you can keep use the outside air pressure for altitude measurement while maintaining your pressure vessel fuselage.

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We at use DAM-AD17 pressure exchange membranes which let air through but dont let water in:

This way we can use regular barometers within our watertight 3d printed box:

That’s what I would do too. There are many barometer chips available that have a tubed port, and they are usually able to take not just air but also water, oil, some acids, etc.

The only worry would be the port clogging, for example by ice.

The port needs to be well located to avoid pressure error due to venturi effect.

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