how does an airplane mesaure its own speed in the air?

Question

that is, without using GPS.

Answer 1

All those are nice long answers...

Getting to the easy point:

The plane has a tube that points into the oncoming air. On the side of the plane is a port that has a small pin hole. The air speed indicator in the plane just measures the difference between the air being forced into the tube and the air thats sitting still in that little hole. No need for a textbook, lol.

Answer 2

It uses air pressure through what is called a pitot tube... a tube that faces the planes direction of travel. And as a reference it uses a static air port. A hole on the side of the plane that feeds into the same air instrument. This will only give you the air speed at which you travel however. The speed across the ground can be judged by the use of a VOR system or an ADF system with distance measuring devices

Answer 3

A Pitot tube is a measuring instrument used to measure fluid flow velocity, and more specifically, used to determine the airspeed of an aircraft. The Pitot tube is named after its inventor, Italian born French engineer Henri Pitot, and was modified to its modern form by Henry Darcy.The basic pitot tube simply consists of a tube pointing directly into the fluid flow. As this tube contains air, a pressure can be measured as the moving air is brought to rest. This pressure is the stagnation pressure of the air, also known as the total pressure, or sometimes (particularly in aviation circles) the pitot pressure.
The measured stagnation pressure cannot of itself be used to determine the airspeed. However, since Bernoulli's equation states that
stagnation pressure = static pressure + dynamic pressure
then the dynamic pressure is simply the difference between the static pressure and the stagnation pressure. The static pressure is generally measured using the static ports on the side of the fuselage. The dynamic pressure is then determined using a diaphragm inside an enclosed container. If the air on one side of the diaphragm is at the static pressure, and the other at the stagnation pressure, then the deflection of the diaphragm is proportional to the dynamic pressure, which can then be used to determine the indicated airspeed of the aircraft. The diaphragm arrangement is typically contained within the airspeed indicator, which converts the dynamic pressure to an airspeed reading by means of mechanical levers.


A pitot-static system is an avionics component which directs impact pressure from a Pitot tube and static air pressure into the appropriate flight instruments. The system allows a pilot to know an aircraft's airspeed, Mach number, altitude, and altitude trend.


Instead of static ports, a pitot-static tube may be employed, which has a second tube coaxial with the pitot tube with holes on the sides, outside the direct airflow, to measure the static pressure.
Pitot tubes on aircraft commonly have heating elements to prevent the tube from becoming clogged with ice.

Answer 4

Airspeed indicator measures the airflow against the airplane with the aid of a pitot tube. GPS provides actual music floor velocity. airspeed is relative to situations (i.e. wind direction and velocity, as nicely as altitude and airpressure) so gps satelite navigation provides the main reasonable velocity. additionally you're able to remember an airplane flies a million-6 miles above the earth floor. So if its GPS floor velocity is one hundred Knotts, a nautical mile 6 miles above the earth is a differnt length than on the floor. yet in a distinctive way is with radio beacons and distance calculations. maximum pilots communicate over with Indicated AirSpeed or IAS EDIT: additionally GPS has lag which makes it no longer up as much as now, you are able to abruptly end and the GPS for some moments (reckoning on high quality of sign and device) will reveal an incorrect v alue.

Answer 5

Simplifying the previous answers,
The pitot tube is the device used to determine the airspeed via the ram air that goes through the tube. To understand how its speed is measured you must understand that it only records airspeed, not ground speed. An aircraft may read 115kts (100mph) on its airspeed indicator but may only be flying at 50kts (43 mph) ground speed. Or vise versa, your airspeed indicator may read 50kts and your ground speed may be 115kts. It all depends on wind and its direction in relation to you. If you get a flight computer, you can do the computations very easily

Answer 6

Several ways. First is a device called a pitot tube which measures the air flow the plane is passing through. Sometimes that is inaccurate because of tail winds, etc. Next is good old navigation. Time how long it takes you to go from one fixed point to the other on your chart. Last, but not least, electronic devices like loran and radar.

Answer 7

By using Pitot tube to measearing the stagnation pressure.

Answer 8

In addition to the previous answers, add or subtract the amount of headwind or tailwind to get your groundspeed.