For
Beechcraft 60,
A60 & B60 Dukes
The
modification consists of two tapered strakes which are approximately
5 ý feet long that are riveted to the underside of the aft
section of the fuselage. Because the rear most portion of
the strakes is actually attached to the tail cone the strakes
incorporate a split design which allows the tail cone and
aft section of the strakes to be removed as one piece for
maintenance. Installed, the kit weighs in at 7 ý lbs.
The strakes are designed to improve the directional stability
of the Duke, reduce aft body drag, and reduce Dutch roll oscillations.
The reduction in Dutch roll is most apparent to the passengers
riding in the back of the airplane and is the main reason
the strakes were developed. Boundary Layer Research test pilot
Bob Desroche said that the aft body strakes "improve the ride
comfort at cruise speeds, and provide a more solid feel at
low speed". He also states that "the company tests indicated
a Vmc reduction of two knots" although BLR did not take credit
for the reduction at certification.
The strakes are available in kit form with all the necessary
parts, installation instructions and certifying paperwork
included. The kit can be installed by any qualified maintenance
facility. Installation time is approximately 16 hours plus
paint. There are no placards added or airspeed indicator dial
changes required with the kit.
PERFORMANCE SUMMARY
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Improved
Directional Stability during takeoff, climb
and landing. |
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• |
Improved
aft cabin ride during low and high
altitude cruise. |
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• |
Improved
stability and handling at high angles of attack and
low speed. |
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• |
Improved
yaw dampening with or without the yaw dampener engaged. |
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• |
Reduced
Aft Body Drag with associated benefits of increased
cruise speed. |
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• |
Additional
2 knot reduction in Vmc. |
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