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Machinbird · 13 June 2009, 03:06 PM

There is a condition you do not want to encounter during the test flying build up on your new aircraft. Flutter. Few living people have any experience with the subject. The subject aircraft in the following sequence was flown by Fred Haise of Apollo 13 fame. The sequence ends just as the flutter is beginning to dampen as the chase pilot wisely backs away from an incipient catastrophic failure.
http://www.nasa.gov/centers/dryden/m...r_test_320.mov
From the relatively low frequency of the oscillation, I think the mode being excited was the spanwise bending mode of the stabilator, but I certainly wouldn't mind someone with more knowledge of the subject providing better information.
There is quite a bit more basic information available on the subject of flutter which is a part of the general subject of Aeroelastic phenomena.
The purpose of this topic is not to put fear into prospective test pilots, but to arm them with the information necessary to recognize that they might be approaching an aeroelastic limit on their flying machine.
Let me know if you would like to see more along this topic and of course, feel free to contribute.
Sid

13 June 2009, 03:06 PM	#231 (permalink)
Machinbird Forum Ace Join Date: Dec 2004 Location: Chicago Area Posts: 583	The Flutter Beast There is a condition you do not want to encounter during the test flying build up on your new aircraft. Flutter. Few living people have any experience with the subject. The subject aircraft in the following sequence was flown by Fred Haise of Apollo 13 fame. The sequence ends just as the flutter is beginning to dampen as the chase pilot wisely backs away from an incipient catastrophic failure. http://www.nasa.gov/centers/dryden/m...r_test_320.mov From the relatively low frequency of the oscillation, I think the mode being excited was the spanwise bending mode of the stabilator, but I certainly wouldn't mind someone with more knowledge of the subject providing better information. There is quite a bit more basic information available on the subject of flutter which is a part of the general subject of Aeroelastic phenomena. The purpose of this topic is not to put fear into prospective test pilots, but to arm them with the information necessary to recognize that they might be approaching an aeroelastic limit on their flying machine. Let me know if you would like to see more along this topic and of course, feel free to contribute. Sid __________________ “If you want to go up, pull back on the stick, if you want to go down, pull back a little bit more.”