Andy wrote:
Eric Greenwell wrote:
To recap, one of the SparrowHawks built for Mississippi State University
broke up in flight Oct 18. The pilot parachuted safely.

I just finished talking to Greg Cole, designer of the SparrowHawk. The
program manager from MSU visited him Monday to discuss the data from the
flight and pictures of the pieces. The short story is the pilot
inadvertently exceeded Vne while performing a rolling maneuver as part
of the test program, and the glider broke apart at 171 knots!


Was the test point intended to be a roll with CASVne or was it not
possble for some reason to perform a roll without exceeding Vne?

Greg was not certain about the reason for the test, but it was supposed
to be conducted under 100 knots. ntil a public determination is offered
for the excessive speed, I don't want to repeat prelimanary remarks that
I got third-hand,but everyone is agreed the speed build up had nothing
to do with the SparrowHawk design.


Is there any indication of the speed at which flutter started?

Based on the air data logger it carried, it broke up at 170 knots
"instantaneously". Given the rapid breakup, and the 170 knot flutter
speed from design calculations, everyone thinks that's when and what
happened.

--
Eric Greenwell - Washington State, USA
Change "netto" to "net" to email me directly

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

"A Guide to Self-launching Sailplane Operation" at www.motorglider.org