Post on 17-Dec-2015
transcript
Extremely Maneuverable UCAV
Team Zebra
Andrew Fischer, Team Leader
Matthew Everingham, Structures and Costing
Connor McCarthy, Aerodynamics and Propulsion
Jim Lang, Project Advisor
Blaine Rawdon, Boeing Company Sponsor
Outline of Presentation• UAV Opportunities• Project Requirements• Mission Profiles• Configuration• Performance• Aerodynamics• Propulsions• Stability and Control• Low Observables• Structure• Future Work• Schedule and Timeline• Conclusions• Special Thanks
UAV Opportunities
Project Requirements
• Create design concept for an extremely maneuverable UCAV that can perform two distinct missions
• Performance up to 9g’s comparable to F-16 & F-15 aircraft for subsonic to transonic flight
• Extended maneuvering capabilities up 20g’s due to increased structural limits and the use of dynamic lift
• Estimate “Value of Maneuverability”
Mission Profiles
•Missions comparable to F-16 and JSF missions
Defensive Counter Air Mission
• Phase 1 – Take off and acceleration allowance• Phase 2 – Climb from sea level to optimum cruise altitude• Phase 3 – Cruise out at optimum speed and altitude for 700 nm• Phase 4 – Combat allowance
• Fuel to perform at 25,000 ft with maximum thrust and fuel flow• One sustained 360º (PS) at M=0.8• Four maneuver-point (instantaneous) 90º turns, recovering to M=0.8 and
25,000 ft altitude after each
• Phase 5 – Climb from 25,000 ft to optimum altitude• Phase 6 – Cruise back at optimum speed and altitude• Phase 7 – Descend to sea level• Phase 8 – Reserves: fuel for 30 minutes at sea level at speed for
maximum endurance
Hi-Lo-Lo-Hi Interdiction Mission
• Phase 1 – Take off and acceleration allowance• Phase 2 – Climb from sea level to optimum cruise altitude• Phase 3 – Cruise out at 500 nm at optimum speed and altitude• Phase 4 – Descend to 200 ft• Phase 5 – Dash out 100 nm at M=0.8 at 200 ft• Phase 6 – Weapons Delivery:
• Small Diameter Bombs are delivered in aggressive turning maneuvers. Retain air-to-air missiles throughout the mission
• Phase 7 – Dash back 100 nm at M=0.8 at 200 ft• Phase 8 – Cruise back 500 nm at optimum speed and altitude• Phase 9 – Descend to sea level• Phase 10 – Reserves: fuel for 30 minutes at sea level at speed for
maximum endurance
Target Laydown
Maneuverability and Speed Issues
• Higher speed requires greater load factor capabilities
• Symmetrical design allows pitching oriented maneuver to replace roll maneuver
• Negative Ps during high g turns complicates the maneuvering
Target Attack Speed versus Load Factor Requirement
0
100
200
300
400
500
600
700
0 5 10 15 20 25
Load Factor
Ve
loc
ity
(k
no
ts)
Sample Tgt Laydown
Targets Attacked per Minute vs Load Factor Capability
0
1
2
3
4
5
6
7
0 5 10 15 20 25
Load Factor
Ta
rge
ts A
tta
ck
ed
/ M
inu
te
Sample Tgt Laydown
Roll Angle vs Load Factor for a Sustained Turn
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25
Load Factor
Ro
ll A
ng
le (
de
gre
es
)
Sustained Turn
Performance: PS
Performance: PS
Performance: Turn Rate vs. Mach
ExMan Exclusive: Dynamic Lift
Take-off and Landing Parameters
• Take-off distance = 1230 ft
• Landing distance = 3678 ft
• Vstall,TO = 155 ft/s
3-View of Planform
Internal Components
Aerodynamic Characteristics
• Leading edge wing sweep - 50°• Aspect Ratio – 4• Taper Ratio, λ - 0.25• Root Chord – 20 ft• MAC – 14 ft• t/c - .09• NACA 0009 Airfoil
• Uncambered• Clmax – 1.32
Drag due to Lift Factor, KMach # vs. K
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Mach #
K
Combat Region
MCR
Zero Lift Drag Coefficient, CD0
CD0 vs Mach #
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Mach #
CD
0
Combat Region
MCR
• Drag Polar – CD=.007+.1CL2
(L/D)max
(L/D)max vs. Mach #
0
2
4
6
8
10
12
14
16
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Mach #
(L/D
) max
Combat Region
Stability and Control
• Aerodynamic Center – .25 of MAC• Static Margin - .0285• Longitudinal, lateral and directional neutral stability• Large control surfaces for high pitch acceleration (°/s2)• Leading edge controls for high lift
• Chord length – 3 ft• Acting over >90 % of wing area
• Trailing edge controls for maneuvering• Chord length – 3.8 ft• Acting over 80% of wing area• Plain flaps
High Lift DevicesCL Versus Angle of Attack at M=0.6
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
-20 -10 0 10 20 30 40 50
Alpha, degrees
CL
0 degree T.E. f laps
10 degree T.E. f laps
20 degree T.E. f laps
30 degree T.E. f laps
L.E. f lapsCLbuffet
CLmax
High Lift Devices, cont.CL vs. Angle of Attack at M=0.8
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
-20 -10 0 10 20 30 40 50
Alpha, degrees
CL
0 degrees T.E. f laps
10 degrees T.E. f laps
20 degrees T.E. f laps
30 degrees T.E. f laps
L.E. f laps
ΔCLmax,high lift
Dynamic LiftCL,Dynamic vs. Angle of Attack at M=0.8
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 5 10 15 20 25 30
Alpha, degrees
Cl
0 deg/sec
30 deg/sec
60 deg/sec
90 deg/sec
ΔCLmax,dynamic
ΔCLmax,dynamic is proportional to ά/V
Longitudinal StabilityCM vs. Angle of Attack
-0.05
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0.05
-30 -20 -10 0 10 20 30
Alpha, de gre e s
CM
Cm vs. AoA
Trim Point
Propulsion System• Two Pratt & Whitney F-100-PW-100 engines scaled
down a factor of .652 - 1784 lbs each• Combined SLS thrust of 46000 lbs• Dimensioning:
• Engine length – 153.4 in• Compressor face diam.– 32.29 in• Max diam. – 35.5 in• Airflow to each engine – 141.4 lbm/sec• Bleed airflow for each engine – 0.4 lb/sec
• Possible options for operating over 9g’s• Dual-cycle engine (turbofan and ramjet)• Build a 20g engine
Maximum ThrustMaximum Thrust Versus Mach # with Varied Altitude in 1000ft
0
5
10
15
20
25
30
35
40
45
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Mach #
Th
rust,
1000 lb
s
0 ft
5 ft
10 ft
15 ft
20 ft
25 ft
30 ft
0
5
10
15
20
25
30
Military Thrust
Military Thrust Versus Mach # with Varied Altitude in 1000ft
0
5
10
15
20
25
30
35
40
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Mach #
Th
rust,
1000 lb
s
0 ft
5 ft
10 ft
15 ft
20 ft
25 ft
30 ft
0
5
10
15
20
25
30
TSFCTSFC (Max T.) vs. Mach # with Varied Altitude in 1000ft
1.8
1.9
2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Mach #
TS
FC
, lb
/lb
-hr
0 ft
5 ft
10 ft
15 ft
20 ft
25 ft
30 ft
0
510
15
20
25
30
Inlet and Nozzle Details
• Axisymmetric pitot inlet – subsonic consideration• Dimensioning:
• Inlet diameter – 24.96 in• Diffuser length – 129.12 in
• S-shape diffuser to reduce radar detection• Pressure recovery in diffuser – 97.14 %• Short convergent nozzle
• Good overall• Potential for thrust vectoring• Slight drag penalty
• Long fairing between nozzle exits• Reduce acoustic interference• Slight drag penalty
Low Observables: Options
• 4 spike configuration• Head on into radar w/ minimal detection
• S-inlet duct w/ radar absorbing material• Increase in LO• decrease in thrust
• Edge Treatments• Increase in LO
• Wempty increase
Center of GravityComponent and Aircraft Center of Gravity
-35
-30
-25
-20
-15
-10
-5
0
-30 -20 -10 0 10 20 30
Y distance (ft)
X d
ista
nce
(ft
)
CG of Aircraft
Engine 1(Left)
Engine 2(Right)
ICNIA
Data bus
INEWS
ALE-50
Vehiclemanagement systemIRSTS
Active Array Radar
LANTIRN NavigationsystemLANTIRN TargetingsystemHARMTargetingsystemElectrical System
APU
OBIGGS
16 250 lb Bombs
Missile Bay 1 (Left)
Missile Bay 2 (Right)
Fuel Tank 1
Fuel Tank 2
Fuel Tank 3
Fuel Tank 4
Front Landing Gear
Rear Landing Gear(Left)Rear Landing Gear(Right)
Travel of Center of Gravity
CG Travel
0
10
20
30
40
50
60
70
80
90
100
89 90 91 92 93 94 95 96 97 98
CG % MAC
Fu
el W
eig
ht
(%)
Structure• 20g structure
• maneuverability outside of human limits• higher lethality
• higher survivability
• Lower factor of safety• Lowered from 1.5 to 1.25
• exploitation of opportunities exclusive to UAVs
• Span Loading• decrease in bending moments on main wing structure
• reduces dependence of structure weight on load factor
Structure Empty Weight Dependence on Load Factor
• The reduction of load factor dependence between span loading and non-span loading was determined using MATLAB model of a basic wing box.• The exponent of load factor was found to be reduced by 0.2, from 0.59.
• Normally, a refined empty weight estimate made based on historical data for A/C components.• In this case, the load factor dependence determined from the MATLAB
program was used with the historical data to produce an empty weight estimate of ExMan.
• An empty weight estimate of the F-16 configuration was also created, using the same historical relations, but with the body-wing dependence on load factor.
Structure Empty Weight Dependence on Load Factor(continued)
• The relation of empty weight to load factor based on the actual empty weight of the F-16 was created to determine the empty weight of an F-16 which has been scaled up to handle up to 20gs.
• A similar relation for the empty weight of ExMan was determined assuming the same quantity of non-load factor dependent weight.
• Targets hit per minute was related to empty weight for each aircraft through the design load factor and minimum required turn radius for sample target laydown.• The relation shows that the ExMan UCAV will weigh less than the F-16
for any given load factor.• The ExMan UCAV at a design load factor of 20 is lighter than the F-16 at
a design load factor of 9.
Empty Weight vs Load Factor Capability
0
5000
10000
15000
20000
25000
0 5 10 15 20 25
Load Factor
Em
pty
We
igh
t
Conventional Body-Wing
Span-Loader Config
Possible Trade Studies
• PW-F-100 vs. GE-404 engine
• Double vs. single engine design
• Leading edge inlets vs. top-bottom bifurcated inlets
• Inlet flaps for flow straightening
• Control effectors (ie. Thrust vectoring)
• Mission Radius
• Fuel layouts
Targets Attacked per Minute vs Empty Weight
0
1
2
3
4
5
6
7
0 5000 10000 15000 20000 25000
Empty Weight
Ta
rge
ts A
tta
ck
ed
/ M
inu
te
Conventional Body-Wing
Span-Loader Config
F-16
Ex Man UCAV
Conclusions•Performance up to 9g’s comparable to F-16 & F-15 aircraft for subsonic to transonic flight•Extended maneuvering capabilities up to 20g’s due to increased structural limits and the use of dynamic lift•Symmetric design able to perform positive and negative maneuvers with equal performance•Span loading concept results in a lightweight aircraft
Schedule and Timeline
Targets Attacked per Minute vs Empty Weight
0
1
2
3
4
5
6
7
0 5000 10000 15000 20000 25000 30000
Empty Weight
Ta
rge
ts A
tta
ck
ed
/ M
inu
te
Conventional Body-Wing
Span-Loader Config
F-16 type based onhistorical data
Ex Man UCAV