saab 2000 (aew&c) certification for flight in icing conditions wim willemse october 19, 2010
TRANSCRIPT
Saab 2000 (AEW&C)Certification for flight in icing conditions
Wim Willemse
October 19, 2010
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Saab 2000 (AEW&C)Certification for flight in icing conditions
Introduction
Platform Description – external changes
Effect of ice accretion on external changes
Definition of the artificial ice shapes
Flight test
Acknowledgments
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Saab 2000 (AEW&C)Certification for flight in icing conditions
INTRODUCTIONAirborne Early Warning and ControlLatest generation of the ERIEYE radar and Mission SystemSelf Protection SystemIdentification Friend or Foe
The Saab 2000 (AEW&C) should full-fill the same civil certification requirements as the Saab 2000 airliner:
To operate into known icing conditions, the aircraft must be certified in accordance with the criteria of FAR/JAR Part 25, Appendix C.
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Saab 2000 (AEW&C)
PLATFORM DESCRIPTION
DOU
MAW/LWS
Towed decoy
WT pods Chaff/Flare
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EFFECT OF ICE ACCRETION
Wing Tip Pods – Unprotected Effect of Ice accretion
- Increased drag
- Possible effect on aileron aerodynamics
Has been investigated by flight test with
artificial ice shape.
Towed decoy – Unprotected Effect of Ice accretion
- Increased drag
Has been investigated by flight test with
artificial ice shape.
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EFFECT OF ICE ACCRETION
DOU Struts – Protected Clean struts decrease directional stability and
increase the drag.
(Verified by CFD analysis and Wind tunnel tests)
Effect of Ice accretion
- Increased drag – Requires protection
- Decreased strut lift (side force) – Less negative effect on directional stability
Saab 2000 (AEW&C) Aft strut - 45 minutes holding
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
-0.4 -0.2 0 0.2 0.4 0.6 0.8 1x/c
y/c
-20 C
-12 C
-7 C
-5 C
-4 C
-3 C
No ice
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EFFECT OF ICE ACCRETION
Vertical tail extension (30 inches) - Unprotected Effect of the 3 inch double horn ice tested in the wind tunnel.
- Increased drag
- Slightly increased directional stability
- Slightly increased rudder efficiency
Investigated by flight test with artificial ice shape.
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EFFECT OF ICE ACCRETION
MAW/LWS sensors – Unprotected
No significant effect of ice accretion on pitot-tubes and angle of attack vanes
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DEFINITION OF ARTIFICIAL ICE SHAPES
ONERA Ice code
Code produced by Onera
Icing code used for Saab 2000 artificial ice shapes
Accepted by FAA and EASA
2-dimensional code
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DEFINITION OF ARTIFICIAL ICE SHAPES
Icing conditions
Requirement FAR/JAR:
Appendix C
For unprotected parts: 45 minutes holding in Continuous Maximum
pinnacle length up to 3 inch
Droplet size: 20 μm
LWC as function of temperature – according to Appendix C
.
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DEFINITION OF ARTIFICIAL ICE SHAPES
Artificial ice shape on wing tip pod
The ice shape is defined by two shapes: one top view and one side view. The thick red line is the selected shape for flight test. The ice shapes are made dimensionless with the “chord length”: 2.14mRoughness has been added up to 10 % length of the wing tip pod:
(a) roughness height: 3 mm(b) particle density: 8 to 10/cm2
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Saab 2000 AEW&C Ice accretion on wing tip pod - top view
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
-0.02 0.00 0.02 0.04 0.06 0.08 0.10
-20 C
-12 C
-11 C
-10 C
-9 C
-8 C
-7 C
-6 C
-5 C
-4 C
-3 C
-2 C
No ice
flight test shape
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Saab 2000 AEW&C Ice accretion on wing tip pod - side view
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
-0.04 -0.02 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14
-20 C-12 C-11 C-10 C-9 C-8 C-7 C-6 C-5 C-4 C-3 C-2 CNo iceflight test shape
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Artificial ice shape on towed decoy
The ice shape is defined by two shapes: one top view and one side view. The thick line (-6 C) is the selected shape for flight test. The ice shapes are made dimensionless with the “chord length”: 1.454mRoughness has been added up to 10 % length of the wing tip pod:
(a) roughness height: 3 mm(b) particle density: 8 to 10/cm2
DEFINITION OF ARTIFICIAL ICE SHAPES
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Saab 2000 AEW&C Ice accretion on towed decoy - top view
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
-0.05 0.00 0.05 0.10 0.15 0.20
-2 C
-3 C
-4 C
-5 C
-6 C
-7 C
-8 C
-9 C
-10 C
-11 C
-12 C
-20 C
No ice
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Saab 2000 AEW&C Ice accretion on towed decoy - side view
-0.07
-0.05
-0.03
-0.01
0.01
0.03
0.05
0.07
0.09
-0.05 0.00 0.05 0.10 0.15 0.20
-2 C
-3 C
-4 C
-5 C
-6 C
-7 C
-8 C
-9 C
-10 C
-11 C
-12 C
-20 C
No ice
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DEFINITION OF ARTIFICIAL ICE SHAPES
Vertical tail extension - Ice shape at c = 1.370 m45 minutes holding
-0.12
-0.10
-0.08
-0.06
-0.04
-0.02
0.00
0.02
0.04
0.06
0.08
0.10
0.12
-0.10 -0.08 -0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14
x/c
y/c
clean profile-9 C-8C-7 C-6 C-5 C-5 C; 3 inch ice shape; selected for flight test-10C-9C-8C-7C-6C-5.5C-5C-5.5 C; 3 inch ice shape; selected for flight test
Artificial ice shape on vertical tail extension
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Saab 2000 (AEW&C) FLIGHT TEST
Flight in natural icing• boots on DOU struts
Dry-air flight test with artificial ice shapes• Effect on flying qualities• Aircraft performance
#1B-AEW Approach ice. 0.5” on protected, 3” unprotected#5-AEW Left Upper Wing failure case. 1.5” on failed surface.
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Saab 2000 (AEW&C) Dry-air flight tests Flying Qualities tests
Test\Ice 1B 5
Stall Characteristics X X
Push Over to 0 g X
Directional Control X
Lateral Control X
Steady Heading Sideslip X X
Dutch Roll X
Vibration and Buffeting X
Landings X X
Selected Flying Qualities tests, artificial ice configuration and flight conditions are ”worst case” from the Saab 2000 certification.
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Acknowledgments
Nenad Jankovic – Manager applied aerodynamics
Per Weinerfelt – Specialist Mathematical and numerical modeling
Henrik Åslund – Senior Research Engineer Aerodynamics
Karl-Erik Eklund – Advanced Design Engineer
Ronny Gyllensten – Advanced Design Engineer