Why do experimental aircraft have such long tubes on the nose?

Question

Why do experimental aircrafts (like the X-35, the Space Shuttle Enterprise, the H160 or the X-15 in the pictures) have such long Pitot tubes at the nose when compared to the production aircraft? Are they for taking test measurements?

Answer 1

Yes- you can see an array of little doodads sprouting from the pitot probe in this photo, they are for accurately measuring the direction of airflow in 3 dimensions. They also are long to ensure that the measurements will not be too badly disturbed by the fuselage of the plane itself.

Answer 2

Air pressure varies greatly along the fuselage of the aircraft and while the general average distribution can be modeled quite accurately, local variations can be enough to cause significant error in pressure measurements. Also when aircraft is subjected to extreme flight conditions errors in pitot tubes and static ports can render flight instruments useless. When test flying new aircraft long pitot tubes and trailing static pressure sensors are used to ensure the probes are free of any interference the body of the aircraft may cause.

During the test flight campaign location of the probes and calibration of flight instruments are finalized so later production aircraft can have accurate pressure sensing within their entire envelope.