Programme
Discussions
Wissenschaftstag
Braunschweig
2015
Kevin Nicholls, EIVW
Prepared by Heinz Hansen
TOP-LDA Leader, ETEA
Presented by Bernhard Schlipf, ESCRWG
Laminarität für
zukünftige
Verkehrsflugzeuge
Überblick,
Anforderungen
und
NLF
Slat on
A320
Status
Quick Technology Evaluation
(Performance
only)
Ergebnisse des
AirbusTechnologieprogramms
Low Drag Aircraft (TOP-LDA)
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Content
1
TOP LDA Introduction & Overview
2
Requirements and selected Approach
3
Structure Concepts Status
4
Manufacturing and Flight Test Demonstration
5
Summary & Outlook
Page 2
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Content
1
TOP LDA Introduction & Overview
2
Requirements and selected Approach
3
Structure Concepts Status
4
Manufacturing and Flight Test Demonstration
5
Summary & Outlook
Page 3
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
Jet Fuel Price as Driver for
Performance Improvement
5$
12 Sep 2008
4.81 $ / gal
Jet fuel price
15 Sep 2008
Lehman Brothers
Source: US Energy Information Administration, 9 November 2012
4$
first major Airbus
laminar R&T
activities
3$
First gulf war
Second gulf war
2$
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
11 Sep 2001
1$
0$
Jan. 90
1990-2001
average
59 ct / gal
Jan. 94
Jan. 98
Jan. 02
Jan. 06
restart of Airbus
laminar R&T activities
Jan. 10
Jan. 14
Drag reduction (by laminar flow) and efficient engines
are key elements for reduction of fuel consumption
Page 4
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
What is laminar flow?
Schematic Representation of Boundary Layer
laminar
Skin friction coefficient
turbulent
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
V=0
Aircraft surface
 Laminar flow can reduce friction drag significantly
 Friction drag contributes to total a/c drag with ≈ 50%
 Biggest contributor to friction drag is wing and fuselage
 Laminarisation of fuselage is very challenging
 A laminar wing upper side has a bigger effect than lower side (≈ 65%)
For a typical wing application a reduction of total drag in the order
of up to 8% is possible by laminar flow on upper side
Page 5
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
What are major influence
factors for laminar flow?
Natural laminar flow (NLF):
laminar boundary layer by wing airfoil shape only
Hybrid laminar flow (HLF):
active control (suction, cooling) of boundary layer & airfoil shaping
 Smoothness of wing surface (waviness, steps, gaps, roughness)
 Three dimensional disturbances (fasteners, insects, scratches, ...)
Page 6
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Structure
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
 Wing pressure gradient (= airfoil shape)
 Reynolds number (= size, speed, altitude)
 Leading edge sweep (= Ma number)
Aero
Laminar flow influenced mainly by:
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
Characteristics of
laminar Airfoils
Cp
turbulent
laminar
turbulent
thick & round leading edge
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
• narrow & sharp leading edge
• front spar moved back
• max thickness far aft
• increased rear spar height
laminar
x/c
• accelerated flow needed to get large extent of laminar flow
• this has a negative effect on shock strength (especially at high Ma)
• wing box of laminar wing similar to turbulent but more volume aft
• leading edge: sharp, less space  front spar more aft
Page 7
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
How Hybrid Laminar Flow
works
Hybrid Laminar Flow Control (HLFC)
required at high sweep of leading edge (LE) and high Reynolds number
Can be reached by:
• Optimized aerodynamic shape of the airfoil and
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
• Small suction at the leading edge
for stabilization of boundary layer
• Tight control of the manufactured shapes
to remove perturbations at the skin, and
SUCTION
SHAPING
Page 8
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
A320 VTP Flight Test
with suction 1998
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Content
1
TOP LDA Introduction & Overview
2
Requirements and selected Approach
3
Structure Concepts Status
4
Manufacturing and Flight Test Demonstration
5
Summary & Outlook
Page 9
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
What is different in
comparison to the past?
ATTAS NLF Glove 1987
F100 NLF Glove 1992
A340 HLFC Glove
A320 HLFC Fin
20% 30% 40%50%
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Past: Aerodynamic basic research with glove technology and hand finishing of surface
Today: Realistic structure concept fulfilling aerodynamic requirements and manufacturing at acceptable cost; demonstration of concepts on ground and in FT
Robust
aero design
Specific
wind tunnel
test
Large NLF wing LE
ground demonstrator
NLF wing
Saab
Manufacturing
trials
Joint concepts
DLR
Page 10
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
BLADE Flight Test
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
Surface Requirements:
Experimental approach
Adjustable leading edge step
TSP coating
2D Waviness in LE
+
Step
Xtr movement
2D Step testing
Limit?
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Surface imperfection increase
Realistic
Structure
Simulation
Page 11
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
3D Waviness + Multiple Waves
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
CFD Validation for Surface
Requirements
3D CFD Result
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Experiment in KRG
Ma=.75 Cl=design
Re=13Mio
∆Z enlarged
3D Navier-Stokes
including WTT wall effects
temperature distribution
Page 12
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
Surface quality
measurements
Wing box example
inboard
Flap box example
outboard
flaps measurements before & after assembly
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Stringer
Position
MBF
(Composite Structure)
Manufacturing Waviness is strongly dependent
on build concept (stringer spring in, etc.)
Page 13
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Content
1
TOP LDA Introduction & Overview
2
Requirements and selected Approach
3
Structure Concepts Status
4
Manufacturing and Flight Test Demonstration
5
Summary & Outlook
Page 14
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
NLF Wing Structure
Overview
• Box
• Minimal change to turbulent box configuration
• Lower Skin, Rear Spar and lower flange of Front Spar construction unchanged
• Upper Skin certification challenges for “no fastener” joints and integral front spar cap
• Leading Edge
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
• Change to LE design key to meeting NLF requirements
• Joint to box critical, challenging build requirements and life management
• Slats replaced by Krüger-Flaps
• which provide both high lift and bug protection
• Electric WIPS introduced
Page 15
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
Krüger High-lift and Shielding
Concept and Testing
Definition of acceptable
values for Krueger setting
Constraints for structure and
kinematics concept
Krueger shielding
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Numerical
&
Experimental
Validation
Coating Studies
Kinematics Validation
125° Krueger
Page 16
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
NLF Leading Edge Skin
sub assembly
Deployed Krüger
Thermoplastic
sheet
electrical
WIPS
Substructure
Stowed Krüger
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Erosion shield
Leading edge with
high lift installation
Page 17
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
Examples of Joint and
Fastener Head Options
AGI
filler cover
The joint area and the filler
application is a very critical zone
for a laminar wing structure
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
concept
Several partners are working
on that topic and
flight demonstration in BLADE
DLR
floating joint
Page 18
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
is planned as well
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Content
1
TOP LDA Introduction & Overview
2
Requirements and selected Approach
3
Structure Concepts Status
4
Manufacturing and Flight Test Demonstration
5
Summary & Outlook
Page 19
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
Ground Based Demonstrators
in context of TOP-LDA
Airbus metal LE concept
GKN CFRP LE concept
DLR CFRP LE concept
machined joint
floating joint
metal LE self supported
BLADE demonstrators
Ground Based Demonstrator
in SFWA
Krueger Test rigs
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Saab
GKN
& machined metal LE
4.5m span NLF leading Edge
Check several approaches and
select the best mix out of the different demonstrators
Page 20
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
Upper Cover DLR NLF
Manufacturing Demo
LaWiPro
wing cover tooling
Surface
quality
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
analysis
Major Objectives:
Development of new CFRP
wing cover structure
concept and manufacturing
demonstration for laminar
wing application
Page 21
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Stade 13.6.2013
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
GKN Ground based NLF
LE Demonstrator
Ground based NLF leading edge demonstrator
including Krueger and WIPS integration
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
4.5m length
Major Objectives:
Demonstration of full LE integration of all NLF leading
edge components and manufacturing and assembly
quality of large leading edge parts
Page 22
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
BLADE A340 MSN1
Flight Demonstration
A340-300
Major Objectives:
•
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
•
•
•
•
•
Design and manufacturing of NLF
outer wing
Flight testing of NLF wing with
two different structure concepts
Demonstration and validation of
aero design and CFD tools
Validation that selected structure
concepts are feasible and deliver
expected surface quality
Testing of artificial disturbances
and operation simulation
Testing of Kruegershielding
Page 23
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Representation of laminar
wing on A340 flying test bed
joint
GKN
Leading edge with joint to box
Saab
Continuous surface
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Content
1
TOP LDA Introduction & Overview
2
Requirements and selected Approach
3
Structure Concepts Status
4
Manufacturing and Flight Test Demonstration
5
Summary & Outlook
Page 24
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
Summary and Outlook
• Surface quality is a major challenge for laminar flow application and detailed
knowledge about surface requirements is needed to find best compromise between
structure solution and aero performance
• Specific wind tunnel test have been designed to get such precise requirements
• CFD capabilities further improved and validated to predict such effects
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
• Small, medium size and full wing demonstrators and validation experiments
including large scale flight test with A340MSN1 will be used to get confidence in
what is possible
• There are several activities with different partners running to find the best structure
and manufacturing concept for the leading edge and upper cover of a laminar wing
• Operability of such laminar wings and surface quality degradation effects will be an
additional important topic in the future
Page 25
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
TOP-LDA Vortrag Wissenschaftstag Braunschweig 7. Oktober 2015
What will come next?
Manufacturing of
BLADE large FT
demonstrator
Flight test with NLF
outboard wings on A340
BLADE demonstrator end
of 2017
SAAB
AERNNOVA
Final assembly
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
GKN
HLFC system
Flight test with simplified
HLFC on the VTP
of the A320 DLR ATRA
aircraft in 2017
Wing LE HLFC
Ground Demonstrator
Page 26
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.