Wilson, Grady W. Raspet Flight Research Laboratory, Mississippi State University, Starkville, Mississippi.
- Additional Readings
An aircraft instrument that provides an indication of the vertical change of the aircraft position within the air mass. It is more commonly known as the vertical-velocity or vertical-speed indicator. Contained within a sealed case, it is connected to the aircraft static pressure source, the so-called at-rest air pressure outside the aircraft, through a calibrated leak (see illustration). Although the instrument operates from a static pressure source, it is a differential pressure indicator. The differential pressure is established between the static pressure in the diaphragm or pressure capsule and the trapped static pressure within the case. When the aircraft changes vertical position, the static pressure in the diaphragm changes immediately but, because of the metering action of the calibrated leak, the case pressure will remain at its prior value and cause the needle to show a change in vertical speed. The needle is usually calibrated in feet per minute but may be calibrated in any appropriate unit of length over time. Because of the calibrated leak in the system, a finite time (usually 6–9 s) is required for the pressure inside the instrument to equalize and a reliable rate indication to become available.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Its dedicated editorial team is led by Sagan Award winner John Rennie. Contributors include more than 9000 highly qualified scientists and 42 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 17,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information