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Multidisciplinary Design Multidisciplinary Design Optimization of a Optimization of a
The golden age of seaplanes is The golden age of seaplanes is long gone…long gone…
because of:because of:• Higher weightHigher weight• Higher dragHigher drag• CorrosionCorrosion
Power-to-weight ratio of Power-to-weight ratio of planing boats and airplanesplaning boats and airplanes
0
0,05
0,1
0,15
0,2
0,25
0 100 200 300 400 500
Cruise velocity, km/h
Po
we
r to
we
igh
t ra
tio
, k
W/k
g
Seaplanes
Landplanes
Planing Boats-Calm sea
Planing Boats - Stormy
Empty weight to Maximum Empty weight to Maximum take-off weight of commercial take-off weight of commercial seaplanes and landplanesseaplanes and landplanes
0,4
0,45
0,5
0,55
0,6
0,65
0,7
0,75
0 1000 2000 3000 4000
Range, km
EM
/MT
OW
Seaplanes
Landplanes
Empty weight to Maximum Empty weight to Maximum take-off weight of LSA take-off weight of LSA seaplanes and landplanesseaplanes and landplanes
0,4
0,45
0,5
0,55
0,6
0,65
0,7
0 500 1000 1500 2000
Range, km
EW
/MT
OW
LSA seaplanes
LSA landplanes
Advantages of composite Advantages of composite structures for amphibious structures for amphibious aircraftaircraft• Eliminate corrosionEliminate corrosion
• Reduce weightReduce weight
• Cheaper maintenance and longer lifeCheaper maintenance and longer life
Sandwich structuresSandwich structures-lighter, because they are stiffer-lighter, because they are stiffer-cost-effective-cost-effective-can be more damage tolerant-can be more damage tolerant-provide flotation-provide flotation
Single Skin Laminate- Blunt Projectile Damage
Sandwich Laminate- Blunt Projectile Damage
Photo by High Modulus (NZ) Ltd.
Application of the progress in Application of the progress in planing boats designplaning boats design
Optimization of planing hullformsOptimization of planing hullforms
• ResistanceResistance
• Longitudinal and lateral stabilityLongitudinal and lateral stability
Experience with composite hull Experience with composite hull structuresstructures
• DesignDesign
• UsageUsage
Amphibious aircraft design is Amphibious aircraft design is multidisciplinary by nature – there are multidisciplinary by nature – there are contradicting requirements for contradicting requirements for aerodynamics, structural performance and aerodynamics, structural performance and
• Displacement Froude NumberDisplacement Froude Number
3bC
3
g
VF
Comparison of the hull resistance of planing boats and Comparison of the hull resistance of planing boats and hydroplaneshydroplanes
Speed Regimes of Hull
0 1 2 3 4 5
Displacement Froude Number
Res
ista
nce
Planing Boats
Hydroplanes
Flying boat design is determined by Flying boat design is determined by the take-off conditionthe take-off conditionMost important parameter - beamMost important parameter - beam
• Create physics based metamodels for the drag Create physics based metamodels for the drag and weight of a seaplane hull as functions of and weight of a seaplane hull as functions of length to beam ratio and deadrise anglelength to beam ratio and deadrise angle
• Determine the constraints from the hull Determine the constraints from the hull volume requirements and the necessary volume requirements and the necessary forebody lengthforebody length
• Calculate the design pressures(CS-23)Calculate the design pressures(CS-23)• Build a Pareto front and select the design Build a Pareto front and select the design
parameters according to mission and parameters according to mission and seaworthiness requirements.seaworthiness requirements.
Response surfaces Response surfaces
• Weight / min weight (L/b, Weight / min weight (L/b, ββº)º)• Constant volume of hullConstant volume of hull
Design Study – Design Study – Composite Composite amphibious aircraft amphibious aircraft investigationinvestigationThe benefits from replacing The benefits from replacing
the Al alloy structure with the Al alloy structure with CFRP sandwich one and CFRP sandwich one and optimizing the geometry of optimizing the geometry of the planing hullthe planing hull
0 500 1000 1500
MTOW
AL EW
C EW
Weight, kg
Series1
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
Al alloy Composite
Em
pty
wei
gh
t fr
acti
on
Series1
Future WorkFuture Work
• Improve the metamodels with Improve the metamodels with application of kriging or radial basis application of kriging or radial basis functionsfunctions
ReferencesReferences
1.Diehl, W. – The application of basic 1.Diehl, W. – The application of basic data on planing surfaces to the data on planing surfaces to the design of flying-boat hulls, NACA rep design of flying-boat hulls, NACA rep No 696, 1940No 696, 1940
2. Munro, W2. Munro, W.. – – Проектирование и Проектирование и расчет гидросамолетоврасчет гидросамолетов – – Москва Москва 19351935