30_Hansen 110607 MACC Briefing

8/3/2019 30_Hansen 110607 MACC Briefing

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Hovercraft Wing-In-Ground (WIG)Platform Research

Eric Hansen15 June 2011

DISTRIBUTION STATEMENT A: Approved for Public Release; distribution is unlimited


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26/24/2011 DISTRIBUTION STATEMENT A: Approved for Public Release;

distribution is unlimited

Getting Popular Knowledge Behind Us:

Wing in Ground (WIG) craft compress air against the surface of the

earth effectively increasing efficiency (L/D)

The Soviets in the 50s built numerous flying ships (Caspian Sea

Monster) which had questionable utility and the technology never wentanywhere

Despite numerous initiatives, WIGs have never found sufficientutility and value to be successful and prolific

Activity in commercial (Europe / Asia primarily) development havebeen ongoing for transport, military and hobby applications.

The Advantages of Cost Efficiency for marine transport remaincontroversial


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A Quick History

Wing in Ground (WIG) craft compress air against thesurface of the earth effectively increasing efficiency (L/D)

DISTRIBUTION STATEMENT A: Approved for Public Release;



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Iranian Bavar-2

Iranian Sacred Defense celebrations, Sept 2010 Operational Squadron of Ground Effect Vehicles (GEV)

Domestically Built 1 & 2 Seat; Oceangoing; 130 km/hr (est.)

Reverse Delta wings / Large Tail; Lippisch design (similar to X-114)

Machine Guns, Surveillance Equipment, Radar Evading (claimed)

Patrol, Recon. & Harass; Work with Zulfikar fast patrol boats armed with Iranian Nasr-1medium range anti-ship missiles / swarm

[Mehr News Agency]

[Mehr News Agency]

[Photo: Fars news agency, by Vahid reza Alaei.]

[Mehr News Agency]




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Classifications

Type A: No Out of Ground Effect Capability

Type C: Full Flight Capability (Aircraft)

International Civil Aviation Organization (ICAO) and IMO agreed

Type A and B WIGs will come under the jurisdiction of theIMO. Type C WIGs however will be classified as aircraft and

will come under the jurisdiction of the ICAO.

Type B: Flight Capability up to 150 meters; ~ 500 feet




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Two Types of WIG Design Approaches

Span Dominated Ground effect (SDGE)

Aspect Ratio (wingspan to chord) is increased Improved Lift / Drag Ratio (more efficient)

Chord Dominated Ground Effect (CDGE) Air is captured (Ram Effect) Lift is increased




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Considerations

ADVANTAGESLife Cycle & Operating costs / logistics same as Boats

Operational (flight) training ~ 20hrs; Similar to boats

Low Infrastructure and Basing Requirements

Low Operator physical stress; higher comfort level

High Fuel Efficiency

LIMITATIONSCurrently impacted by weather conditions

Operations in High Sea States not mature

Take-off and Landing

Variable L/D due to large waves

Current designs are not highly maneuverable in flight

Transport profile closer to aircraft than boats

[Ref. 1]




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What Small Wing in Ground CraftARE good for:

Certain Aircraft CONOPS (low altitude)

Low operational costHigh Speed Range

40 knts to +200 knts Rapid ingress and egress capability

Pursuit & Intercept of conventional craft

Operations in shallow, hazardous Waterways(logs, mines, obstacles, etc.)

Less vulnerable to torpedoes and mines

Signature Advantages Nap of the earth flight; reduced radar detection range

Stealth shape possible (fly by wire)




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Wing in Ground Craft are NOT Good For

Current Boat CONOPS and Mission Scenarios

Carrying comparable weight in current CONOPS;troops, armor, etc.

However, WIGs can be designed to carry weight athigh efficiencies / speed; high transport factors at

different CONOPs

Close in maneuvering at speed Tight turns in flying mode

Operations in High Sea States (currently) Suitable flight within ground effect in high sea states Takeoff and landing in high Sea States




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Interdiction of Fast Boats

All Go-Fast Boats operate in the same speed regimes

Aircraft are required to intercept in reasonable time

Rapid response in a harbor or coastal area to a need




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Rapid Response over Wide Areas

Multi-mission WIG pursuit variants

would not replace Navy Helicopters or fastconventional craft. It would complement andfree them for more demanding missions.

Lower cost to operate than a helicopterand faster than any water born craft, WIGscan traverse uncertain, shallow water,minefields, low land terrains, and can bevery stealthy.

Multiple units could be staged at any small

base (like other boat craft) which couldprovide the rapid response and interceptionsimilar to aircraft over wide areas at anaffordable cost.




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Existing Navy Prototype History

Acquired by NSWCDD in CY06 for SLY FOX.

Transferred to NSWCCD in CY07 from NSWCDD

Restored to safe operational condition and modified forexperimentation as a Navy test asset

Unmanned / Manned applications

Surrogate Enemy, JFCOM Empire ChallengeMay / June 2011

(UH owned sister craft was used; Navy craft mods not completed in time)

Universal Hovercraft developed the first flying hovercraft.

The prototype first took flight in 1996 near Cordova,Illinois on the Mississippi River.




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Modified Universal HovercraftModel UH-19XRW

Hovercraft mode:Speed: 75+ mph

Cruise: 50 mphPayload: 1,000 lbsPassengers: 2 Cabin: 7 x 4

Endurance: 3.5 hoursLength: 19.5 feet Width: 7.5 feetEngine: 2.0 L Chevy EcotecSupercharged

Hoverwing modeSpeed: 70 mphCruise: 55 mph in flightPayload: 600 to 1,000 lbs in flight

Passengers: 2Endurance: 2.5 hoursLength: 24.5 feetWing Span: 22 feetCruise altitude: 3 to 4 feetMaximum altitude: 15 to 20 feet




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Research Capabilities Supported

Utility for Force Protection and Patrol

Capability vs. Cost based on hard data.

High Sea State operations

Launch and Landing (elevated flight deck)

Nap of the Earth Flight technology

Signatures

Bogie (surrogate enemy) Unmanned Applications

Payload experiments[Ref. 2]




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Take Off and Landing Variants

HydroskiHigh Hydrodynamic Lift

Poor L/D for Take OffGood for Landing

HydrofoilsHigh Hydrodynamic LiftGood L/D for Take OffLow heave

X114-H Accident

PAR (Power-Augmented-Ram)High Thrust to Lift

High Take-Off Weight/PowerLow Efficiency

HovercraftLow Thrust to LiftLow Hydro & Hump DragHigh Heave / Bad in Sea State

Taxi over flat land & obstacles




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Nap of the Sea Flight

Average h/c 50% (.5) for IMO Ruling

19XRW cruises at 3-4 ft; SS3-4 Larger chord will be required for higher

Sea State operations as class B

Stability and Control Issues:Non linear dependence of aerodynamic

characteristics with height

Stable in height

Unstable in pitch Long period (phugoid) oscillations Currently manageable by design andmodern control technologies

Stable in YawZoom Turns; Flying higher and banking

Flat turns; requires vertical foils

[Ref. 2]

[WMO]




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Pitch Stability and Solutions

Problem:The lift vector of a wing is located far aft at very

small ground clearances and moves foreword whenclimbing out of ground effect.

Large Tail: (Ekranoplan)Increased pitch control authorityHigher Drag, Most popular solution

Tandem Bi-Wing DesignLimited stability rangeIncapable of OGELow Seaworthiness

S shape Airfoil SectionReduced CP movement , Not as Efficient

Reverse Delta Wing (Lippisch)

Low CP movement and high L/D

Canard DesignTake Off Advantage (feeds air to main wing)Very efficient, Long pitch moment armIdeal for Fly by Wire; promising, however, unstudied

[Ref. 1]

[Typical]




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Angle of Attack effect on PC and Height

Large Change in Pressure

Coefficient with small changes inaltitude between h/c 0.08 and 0.3.

Lift varies with Close WaveCrossings leads to vibrational

heave

Precise control surface motionrequired to stay in .5 h/c averagefor class B

Implies Higher Speeds at LowAngles of Attack in Sea State

[Ref. 2]




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Consideration of Low Flight over Waves

Flight Dynamic Frequency with Aspect: Wave Speed + Flight Speed (into Sea) Wave Speed Flight Speed (with Sea)

Intelligent Control System to manage

SS3 Waves: 3.5 to 5 ft 2.5 - 7.5 sec periods

Wave length ~ 46 65 ftSS4 Waves: 6 to 7.5 ft

2.5 - 9.5 sec periods Wave length ~ 72 92 ft

SS5 Waves: 8 to 12 ft

3 12 sec periods Wave length ~ 105 to 158 ft

h = 1.54 (Hs)/2 + 0.1 x chord

USSR operational experience Safe Operating Height:

(Hs = the average of the 1/3 highest wave)

Hoverwing UH-19XRWPredicted Estimation: Efficient / Safe SS3 Operational SS4

[Ref. 3]

[Ref. 1]

[See References for larger Table]



F t D i C t l T h l i


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Fast Dynamic Control TechnologiesFor High Sea State Prolonged Flight

Elevator / Canard deflection (pitch varies)

Trailing-Edge Flap dynamic deflection

Dynamic Spoilers

Dynamic Venting (air valves in wing)

Wave Sensing K band Radar / LIDAR Ongoing current research

Wave Prediction Technology Ongoing current research MIT & ONR

Height Sensing Phase Radio Altimeter (RA)

Fly By Wire(Computer controlled flight)

Take Off and Landing in a Sea StateRemains an Engineering Challenge!

Acceleration in Waves

Velodyne LIDAR

ICX K-Band Radar

X-Band Radar

[Typical]




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Unmanned WIG Cooperative AutonomousSWARM Missions

Current Maritime Cooperative Autonomy is Maturing

Obstacle Avoidance & COLREGs development

Advanced Perception, Multi-sensor Fusion Radar, Stereo EO & IR, LIDAR, Acoustic

4 USV cooperative; TW11 July HVA protection

UxS CFT Oct Experiment; 4 USV Non Lethal Weapons

Secure Network (certified net to JEC3)Adjustable Autonomy: Human In, On, and Out of the

loop.



USV Non Lethal Weapons Layered Defense


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USV Non-Lethal Weapons Layered DefenseManned Unmanned Integration




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10 Conclusions & Closing Thoughts

2) Small WIGS promise affordable wide area rapid access & control Protected Waters near term / Open Ocean far term

1) Small WIGS should not be applied to current boat CONOPs

5) Large WIGS for efficient material transport remain controversial

4) Class B status allows aircraft performance at small boat costs

7) High Sea States point to larger chords and higher speeds

6) High Sea State operations feasible, but TO & LD is a challenge

8) Hovercraft capability is a very good solution to TO & LD

drag reduction and has overland benefits

3) No special basing or logistics are required and flying is easy

9) Intelligent lethal SWARMs of stealthy expendable WIGs fit intothe DoD vision of integrated robotic warfare

10) A Next Generation combat craft..




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References / Notes

References:

[1] Halloran, M. and OMeara, S. Wing in Ground Effect Craft Review DSTO-GD-0201, DSTOAeronautical and Maritime Research Laboratory (1999).

[2] Christopher Gamble, Joel Martin, Matthew Eggert, Michael Trott; U.S. Air Force Academy, RobertButler, Steven Morris, Jean Slane; Engineering Systems Inc., Billy Crisler, Possum Works. (2008)Analysis of a Wing and Hoverwing in Ground Effect, U.S. Air Force Academy, Air Force Research

Laboratory, CO

[3] Pierson, W. J.; Moscowitz, L. (1964), "A proposed spectral form for fully developed wind seasbased on the similarity theory of S A Kitaigorodskii", Journal of Geophysical Research 69 (24): 51815190

[4] Morris, S., Butler, R., and Slane, J. Characterization of a Hovercraft (HC)/Hoverwing (HW). Aero471 Aeronautics Laboratory Spring 2007 Research Project List.

Notes:

1) Typical For illustration purposes only

2) Unreferenced pictures and illustrations from multiple sources in the public domain




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References / Sea Spectrum

[Ref. 3]


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