- #1
Graviman
- 19
- 0
I am currently very confused about how an altimeter works. I understand that stagnation pressure is the pressure of bringing the flow to rest, and that static pressure is the pressure flowing with the fluid (air in this case). What i don't understand is that the static port is used for altimeter, while pitot tube is used for air speed indicator.
I've always understood that the venturi effect is explained because the total stagnation pressure remains constant, while dynamic pressure changes - thus the static pressure changes. If that is so why doesn't altimeter alter with speed? Alternately what is to stop the static port being put on the wing? Ahhh!
This has come about because of a discussion with some helicopter test pilots about how ground effect reduces hover power. I thought i understood this stuff but I'm coming unstuck. Pan! Pan! Pan!
Mart
I've always understood that the venturi effect is explained because the total stagnation pressure remains constant, while dynamic pressure changes - thus the static pressure changes. If that is so why doesn't altimeter alter with speed? Alternately what is to stop the static port being put on the wing? Ahhh!
This has come about because of a discussion with some helicopter test pilots about how ground effect reduces hover power. I thought i understood this stuff but I'm coming unstuck. Pan! Pan! Pan!
Mart