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Posted for "clark baker" <cbaker9@nyc.rr.com>:
Was the position of your elevator normal or did I see a very large
amount of nose-down elevator in compensation for the ice? If yes,
please tell us more about the handling. Did the wing ice create nose-up
pitching? Did the tail ice create greater aerodynamic negative angle of
incidence compensated by the added down elevator?
Scott Krueger<<
Scott, I noticed the large nose-down position of the elevator also (in
the picture). Due to the significant negative effects the ice buildup
created, we did not feel like exploring the handling envelope. However,
I can make several observations:
- First, I was shocked at how rapidly the ice accumulated- almost
like we went from no ice to noticeable ice. I would equate the
size/shape of the ice buildup on the wing to a broomstick handle, cut in
half, glued to the leading edge. The ice buildup on the tail appeared
moderately greater (which I understand is quite common). The ice
formation was much different than another ice encounter (more gradual
buildup) that produced a much more uniform coating on the leading edge
(which had only a slight negative effect on performance).
- The speed/performance decay was quite surprising (at
approximately 9k msl). The 45kt loss in speed may have been a slight
exaggeration, but the decline was at least +30kts.
- The handling/performance felt very sluggish/heavy. We did not
notice anything else that unusual, including the large nose-down
elevator position. I have the Mark II tail, which has fairly powerful
trim capabilities, so we may have unconsciously trimmed that effect away
- I do not know how much of the performance loss was due to
propeller ice (I have the MT 3 blade), although studies by Cessna show
that propeller ice is a noticeable, but NOT substantial, part of the
performance loss. I am not an engineer, and am also curious what aerodynamic effect may
have been responsible for the unusual elevator position.
Regards,
Clark Baker
N250JF
LNC2 360
http://lancair.net/Lists/lml/Message/20225-02-B/P1010022.JPG
http://lancair.net/Lists/lml/Message/20225-03-B/P1010021.JPG
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