LDW Aircraft - American Institute of Aeronautics and · PDF file · 2013-03-31wing...
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LDW Aircraft LDW Aircraft A Hybrid Flying Wing Concept A Hybrid Flying Wing Concept
Transcript of LDW Aircraft - American Institute of Aeronautics and · PDF file · 2013-03-31wing...
LDW AircraftLDW Aircraft
A Hybrid Flying Wing ConceptA Hybrid Flying Wing Concept
�� Researcher: Michael DizdarevicResearcher: Michael Dizdarevic
�� Principal Researcher: Faruk DizdarevicPrincipal Researcher: Faruk Dizdarevic
�� VP R&D Soko Aircraft IndustryVP R&D Soko Aircraft Industry
�� Military Training and Combat AircraftMilitary Training and Combat Aircraft
�� B737/757; MD80; A310/330/340 SubB737/757; MD80; A310/330/340 Sub--assemblyassembly
�� Cooperation with CanadAir & EmbraerCooperation with CanadAir & Embraer
�� University ProfessorUniversity Professor
�� 20+ year research of Flying Wing concepts20+ year research of Flying Wing concepts
About UsAbout Us
LDW General FeaturesLDW General Features
�� LLongitudinal ongitudinal DDouble ouble WWing Configuration (LDW)ing Configuration (LDW)
�� 7070--800 passenger capacity range800 passenger capacity range
�� Commercial and Military Applications (Jet or Turboprop)Commercial and Military Applications (Jet or Turboprop)
�� UAVsUAVs
�� Firefighting AircraftFirefighting Aircraft
Flying Wing BackgroundFlying Wing BackgroundGoals
Achieve the highest possible aerodynamic efficiency
by eliminating all wetted areas not generating liftIncrease lift capacity and range
Challenges(naturally stable aircraft)
Flight Safety of Commercial
Aircraft
Aerodynamic Efficiency at
High SpeedRide Quality
Safe level of Pitch Control in All Flight and Weather Conditions
Safe Disposal of Large and Shifting Fuel Mass Away From Passengers
With Required Static Margin
Low Attack Angle at Low Speed During Landing
Design With Efficient Thin Airfoils in the Payload Area
Application of Efficient Aft-Camber Airfoils Across the Span of Large
Airlifting Body
Pitch Trim Efficiency in Cruising Configurations
Low Inertia Forces Across Passenger Cabin During Standard
Flight Procedures
Horizontal Level of Passenger Floor in All Flight Configurations
Daylight Access in Passenger Cabin
Flying Wing ChallengesFlying Wing Challenges
Required Level of Pitch
Control
Flight Safety for Commercial Aircraft
Safe Fuel Disposal and
Low Pitch Control
Impact
Safety With Low Attack
Angle During Landing
Tailless Flying Wing can not deploy trailing edge devices for extra lift production during airport approach and landing because it does not have efficient pitch trim control devices far behind G.C. to compensate for a high negative pitch momentum, hence requiring a significant increase of attack angle closer to stall position, thus together with low efficiency of pitch controls additionally jeopardizing flight safety.
Difficulties with longitudinal stabilization of a single airlifting body of Tailless Flying Wing (T.F.W.) aircraft with multiply longer chords than tube-and-wing (T.A.W.) aircraft by its own pitch control devices whose resulting aerodynamic forces have a much shorter arm from gravity center (G.C.), while the airlifting body with very long chords has a much higher disturbance propensity from external forces, which is especially pronounced at low speeds.
A naturally stable T.F.W. has the position of neutral point (N.P.) at around 25% of mean geometric chord (M.G.C.) with G.C. at around 20%, hence the largest quantity of fuel being disposed aft of gravity center, which results with much larger G.C. shift during flight when compared to T.A.W. aircraft, thus jeopardizing either the natural longitudinal dynamic stability during takeoff if positioning G.C. close to N.P. or otherwise being too stable during landing and having slow response to pitch controls.
Flying Wing Challenges Flying Wing Challenges ……cont.cont.
Efficient Thin Airfoils
in the Payload Area
Aerodynamic Efficiency at High Speed
Application of Efficient
Aft-Camber Airfoils
Across the Wing Span
Pitch Trim Control
Efficiency in Cruising
Configurations
Provide competitive cruising trim efficiency of T.F.W. that has no pitch trim devices at a long distance aft of G.C. The only solution is high deflection of pitch control devices on trailing edge of a large airlifting body in upward direction in cruising configuration over time, thus making airfoils of large airlifting body more reflex and less efficient when compared to T.A.W. airfoils that have pitch trim devices positioned far behind aircraft G.C.
Provide sufficient inner height for passenger accommodation by using airfoils with low relative thickness of under 14% across passenger cabin, especially for aircraft below 250 seating capacity, which is decreasing critical Mach and efficiency at higher speed, while the extension of central section in the area of passenger cabin to decrease relative thickness is challenging from the aspect of pitch control of T.F.W.
Efficient Aft-Camber airfoils shift the resultant aerodynamic force far behind N.P. and G.C. of T.F.W., hence resulting with high negative pitch momentum. Two available solutions to provide static stability include high negative loading of airfoils with the longest distance behind G.C., which decreases the effective airlifting area, hence resulting with higher profile and induced drag, or a combination of reflex airfoils in large central section and aft camber airfoils in outer sections, which requires lower negative loading of outer wings but significantly increasing profile and compression drag of large central section.
Flying Wing Challenges Flying Wing Challenges ……cont.cont.
Low Inertia Forces
Across Passenger Cabin
Competitive Ride Quality
Horizontal Level of
Passenger Floor in All
Flight Configurations
Daylight Access in
Passenger Cabin
Inability to have lateral windows along passenger cabin as being the case with T.A.W. aircraft.
Potential solutions include creating openings on the top of passenger cabin, as well as 2D or 3D window virtualization.
Provide for low inertia loading across the passenger cabin. A potential solution is to group passengers close to symmetry axis. However, it results with small number of passengers relative to T.A.W. aircraft for the same given external dimensions due to short chords of T.F.W.
The challenge is associated with inability to deploy trailing edge devices for extra lift production that require a higher attack angle of aircraft and consequently a higher cabin floor angle when compared to T.A.W.
Flying Wing Challenges Flying Wing Challenges -- SummarySummary
�� It is evident that the improvement of T.F.W. flight safety requiIt is evident that the improvement of T.F.W. flight safety requires the res the addition of a stabilizing body with pitch control devices set faaddition of a stabilizing body with pitch control devices set far behind r behind a large airlifting body.a large airlifting body.
�� The addition of stabilizing surfaces further shifts the N.P. of The addition of stabilizing surfaces further shifts the N.P. of aircraft in aircraft in aft direction thus forming a positive chain of events relative taft direction thus forming a positive chain of events relative to the o the improvement of aerodynamic efficiency.improvement of aerodynamic efficiency.
�� However, the large front airlifting body requires large stabilizHowever, the large front airlifting body requires large stabilizing ing surfaces that are not producing lift or requires stabilizing sursurfaces that are not producing lift or requires stabilizing surfaces to be faces to be shifted far behind airlifting body.shifted far behind airlifting body.
�� A longer distance of the stabilizing body from the airlifting boA longer distance of the stabilizing body from the airlifting body dy increases the wetted area of the connecting bodies that are neitincreases the wetted area of the connecting bodies that are neither her producing lift nor stabilizing aircraft, while a shorter distancproducing lift nor stabilizing aircraft, while a shorter distance is e is decreasing the efficiency of the stabilizing body.decreasing the efficiency of the stabilizing body.
�� Our analyses have shown that the only way to overcome these Our analyses have shown that the only way to overcome these limitations was to design all connecting bodies and all other nelimitations was to design all connecting bodies and all other necessary cessary parasitic wetted areas as either stabilizing or airlifting bodieparasitic wetted areas as either stabilizing or airlifting bodies.s.
Our GoalsOur Goals
�� Improve flight safety of Flying Wing aircraftImprove flight safety of Flying Wing aircraft
�� Further improvement of aerodynamic efficiencyFurther improvement of aerodynamic efficiency
�� Further improvement of engine efficiencyFurther improvement of engine efficiency
�� Achieve the highest possible subsonic speedAchieve the highest possible subsonic speed
�� Significant noise reduction in passenger cabin Significant noise reduction in passenger cabin
and around the airportsand around the airports
LDW ResponseLDW Response
Specific Design of
Front Airlifting
Body
LDW Design Elements
Large Airlifting and
Stabilizing Rear
Sections
Engine Integration
With Stabilizing
Rear Sections
Custom Design of
Connecting Bodies
LDW Response LDW Response ……cont.cont.
Wider Leading Edge
Nose of Central
Section
Specific Design of Front Airlifting Body
Trailing Edge of
Central Section
�Longer chords of airfoils at the outboard ends of the passenger cabin
�Wider passenger cabin next to the cockpit
�Increased aerodynamic efficiency in the same area (lower induced drag)
Net Effects
LDW Response LDW Response ……cont.cont.
Wider Leading Edge
Nose of Central
Section
Specific Design of Front Airlifting Body
Trailing Edge of
Central Section
A higher optimal Forward
Sweep angle between 40°and 45° resulting with much longer airfoil chords across passenger cabin, especially in symmetry plane while still satisfying aerodynamic efficiency of the central section.
Net Effects
LDW Response LDW Response ……cont.cont.
Wider Leading Edge
Nose of Central
Section
Specific Design of Front Airlifting Body
Trailing Edge of
Central SectionNet Effects
�Allowing design of highly aerodynamically efficient business or regional one-isle aircraft up to 100 seats with cabin width of up to 3.8 m and min. isle height of 1.9 m inside airfoils of max. rel. thickness under 14%, while providing for much larger luggage compartments when compared to T.A.W. aircraft.
�Design of 100-300 seat two-isle aircraft with cabin width between 5 and 9 m.
�Three aisle 300-500 seat aircraft with cabin width 8.5-12 m when compared to ~20 m of T.F.W. aircraft.
LDW Response LDW Response ……cont.cont.
Composition and
Position
Stabilizing Sections
Shape and Size of
Stabilizing Sections
�Stabilizing sections on the rear wing are composed of two symmetrical sections that are not directly mutually integrated
�Stabilizing sections are set at a large longitudinal distance behind front airlifting body
Net Effects
LDW Response LDW Response ……cont.cont.
Composition and
Position
Stabilizing Sections
Shape and Size of
Stabilizing Sections
�The planform of stabilizing sections is similar to the planform of Front Wing
�Trailing edge across the span of stabilizing surfaces is covered by elevators
�Inner portion of stabilizing sections having a very long root airfoil chord to join both integral aerodynamic cover and upper ends of “V” support
Net Effects
LDW Response LDW Response ……cont.cont.
Composition and
Position
Stabilizing Sections
Shape and Size of
Stabilizing SectionsNet Effects
�Large stabilizing surfaces are set at the highest possible longitudinal distance behind Front Wing, thus substantially shifting N.P. of LDW aircraft in aft direction along M.G.C. of Front Wing.
�Large elevators of stabilizing surfaces are positioned at the highest possible distance behind aircraft gravity center, hence providing for a substantially higher pitch momentum than elevators of T.A.W. aircraft.
LDW Response LDW Response ……cont.cont.
Engine Integration
Position and
IntegrationShape
�All aircraft engines are grouped side-by-side to have a single integral engine aerodynamic cover with a high aerodynamic reflection for longitudinal stabilization and reduced wetted area by up to 30%�Front portion of aerodynamic cover is having conical air intakes exposed to free airflow, thus collecting a much higher amount of kinetic energy then singular air intakes�Rear portion of upper surface in front of trailing edge is partially perforated with exhaust cones to discharge exhaust jet�Rear portion of engine aerodynamic cover aft of jet engine exhaust is pivotal in vertical direction, thus acting in dual role as a central pitch control device that is changing both airflow around aerodynamic cover and engine thrust vector
Net Effects
LDW Response LDW Response ……cont.cont.
Engine Integration
ShapePosition and
Integration
�Engine aerodynamic cover is inserted between the rear portion of stabilizing sections to have the outermost aft position relative to Front Wing, thus forming a large integral stabilizing body with stabilizing sections
�Identical size and shape of outermost lateral airfoils of engine aerodynamic cover and root airfoils of inner portion of stabilizing sections providing for a smooth aerodynamic and structural integration to prevent lateral slip of airflow around lateral ends of aerodynamic cover, thus additionally increasing its aerodynamic reflection for longitudinal stabilization
Net Effects
LDW Response LDW Response ……cont.cont.
Engine Integration
Position and
IntegrationShape Net Effects
�Large integral engine aerodynamic cover with high aerodynamic reflection for longitudinal stabilization and long distance behind Front Wing substantially shifting aircraft neutral point in aft direction �Central pitch control devices substantially increasing pitch momentum relative to T.A.W. aircraft, especially at low speed with thrust vector change�Conical engine air intakes substantially increasing engine efficiency when compared to T.A.W. aircraft� Outermost aft position of engines behind Front Wing substantially decreasing passenger cabin noise�Deflected jet exhaust in upward direction during takeoff and landing compensating for the negative pitch momentum of trailing edge flaps of Front Wing and simultaneously reducing noise around airports
LDW ResponseLDW Response ……cont.cont.
Connecting Bodies
Position and IntegrationShape
�Connecting bodies are designed as “V” tail supporting elements.�Dihedral angle of “V” tail is under 45°. Optimal dihedral angle needs to satisfy a sufficient bending resistance and low obstruction level of free airflow in front of engine air intakes including highest possible horizontal stabilizing projection, lowest lateral reflection, and lowest possible interference drag.�“V” tail has a high sweepback angle (over 50°) to shift the rear stabilizing body including itself in aft direction as much as possible.�Cross sections of “V” tail are shaped as efficient airfoils with rel. thickness of up to 12% and max. relative thickness behind 50% of airfoil chord length.
Net Effects
LDW ResponseLDW Response ……cont.cont.
Connecting Bodies
Position and Integration Shape
�Upper ends of “V” tail join front free root portions of stabilizing surfaces in front of engine air intakes�Identical shape and size of front portions of stabilizing sections and upper ends of “V” tail, as well as low dihedral angle of “V” tail providing for a smooth aerodynamic integration and low interference drag.�The lower ends of “V” tail are smoothly integrated with vertical reinforcement, thus providing for low interference drag.�Aerodynamically shaped rear portion of vertical reinforcement behind “V” tail is pivotal around vertical axis, thus acting as vertical rudder for directional control of LDW aircraft.
Net Effects
LDW ResponseLDW Response ……cont.cont.
Connecting Bodies
Position and IntegrationShape Net Effects
�High aerodynamic reflection of “V”tail for longitudinal stabilization due to large horizontal projection thereof, efficient airfoils, and smooth integration with rear stabilizing surfaces, as well as a long distance of “V” tail behind Front Wing due to a high sweepback angle is additionally shifting the neutral point of LDW aircraft in aft direction along M.G.C. of Front Wing.
�Vertical reinforcement with rudder and vertical projection of “V’ tail behind aircraft gravity center are increasing the natural directional stability of LDW aircraft, while vertical rudder is providing for sufficient directional control of LDW aircraft.
LDW ResponseLDW Response -- OutcomeOutcome
�� Large stabilizing surfaces together with large integral engine Large stabilizing surfaces together with large integral engine aerodynamic cover and aerodynamic cover and ““VV”” tail set at a long distance behind tail set at a long distance behind Front Wing are shifting the aircraft neutral point behind 60% ofFront Wing are shifting the aircraft neutral point behind 60% ofM.G.C. of Front Wing, thus involving the large integral M.G.C. of Front Wing, thus involving the large integral stabilizing body in positive lift production when Front Wing is stabilizing body in positive lift production when Front Wing is designed with custom aftdesigned with custom aft--camber airfoils, hence resulting with camber airfoils, hence resulting with LDW aircraft configuration.LDW aircraft configuration.
�� The overall aerodynamic effect is equivalent to more than 80% The overall aerodynamic effect is equivalent to more than 80% of total wetted area generating a positive lift in cruising of total wetted area generating a positive lift in cruising configuration with an optimal constant lift coefficient when configuration with an optimal constant lift coefficient when compared to around 40% for T.A.W. aircraft.compared to around 40% for T.A.W. aircraft.
LDW Response LDW Response -- RecapRecap
Front Airlifting Body
LDW Design Elements
Rear Wing Engine Integration Connecting Bodies
�Main Airlifting Surface�Passenger, Cargo, & Fuel loading�Aft Camber Airfoils w/long chords due to stabilizing V-tail and large airlifting Rear Body surfaces
�Secondary airlifting body
�Pitch Control
�Main stabilizing surface
�Secondary Fuel disposal
�Engine Integration
�Increasing airlifting and stabilizing effects of Rear Body
�Additional pitch controls
�Improved Engine efficiency
�V-tail connecting Front and Rear Wings�V-tail stabilizing surfaces�V-tail w/Rear Body is a sturdy box-like structure�V.R. role as connecting means�Vertical Rudder
BenefitsBenefits�� More than 70% lower fuel consumption due to higher aerodynamic More than 70% lower fuel consumption due to higher aerodynamic efficiency, lighter airframe, and higher engine efficiency relatefficiency, lighter airframe, and higher engine efficiency relative to ive to T.A.W aircraft. T.A.W aircraft.
�� Higher economical cruising speed by up to 10% due to higher Higher economical cruising speed by up to 10% due to higher aerodynamic and engine efficiency, as well as lighter airframeaerodynamic and engine efficiency, as well as lighter airframe
�� More than twice longer range at higher cruising speedMore than twice longer range at higher cruising speed
�� More than twice lower passenger cabin noise due to more than twiMore than twice lower passenger cabin noise due to more than twice ce lower engine thrust and long distance of engines behind passengelower engine thrust and long distance of engines behind passenger r cabincabin
�� More than twice lower noise around airports due to twice lower eMore than twice lower noise around airports due to twice lower engine ngine thrust and upward deflection of jet noise during takeoff and lanthrust and upward deflection of jet noise during takeoff and landingding
�� More than twice lower COMore than twice lower CO22 emissions due to lower fuel consumptionemissions due to lower fuel consumption
�� Higher level of pitch control at low speed despite large Front WHigher level of pitch control at low speed despite large Front Wing due ing due to significantly larger pitch control surfaces set at a very lonto significantly larger pitch control surfaces set at a very long distance g distance behind aircraft G.C. and simultaneous involvement of engine thrubehind aircraft G.C. and simultaneous involvement of engine thrust st vector in pitch control.vector in pitch control.
LDW 150 LDW 150 -- Case StudyCase Study
�� TwoTwo--isle passenger, freighter, and isle passenger, freighter, and military transport aircraft with a military transport aircraft with a cockpit crew of twocockpit crew of two
�� Front Wing and Rear Wing Front Wing and Rear Wing generating 88% and 12% of total generating 88% and 12% of total lift respectively.lift respectively.
�� Three sideThree side--byby--side turbofan engines side turbofan engines within integral cover of Rear Wing, within integral cover of Rear Wing, each rated at 41kN (123kN total).each rated at 41kN (123kN total).
�� Main and Nose landing gears are Main and Nose landing gears are retracted in lateral and forward retracted in lateral and forward direction respectively.direction respectively.
�� Over 70% of airframe made of Over 70% of airframe made of advanced composite materialsadvanced composite materials
�� Passenger cabin is 7.14 m wide Passenger cabin is 7.14 m wide
�� Isle height ranging from 2 to 2.35 mIsle height ranging from 2 to 2.35 m
LDW 150 LDW 150 -- Case Study Case Study ……cont.cont.
VersionsVersions::
LDW 150PLDW 150P
�� Passenger transport aircraft with capacity between 170 and 222 Passenger transport aircraft with capacity between 170 and 222 passengers for short and long distances with range of up to 13,0passengers for short and long distances with range of up to 13,000 km.00 km.
LDW 150FLDW 150F
�� Cargo transport aircraft with capacity of up to 40 tons of payloCargo transport aircraft with capacity of up to 40 tons of payload and ad and range of up to 10,000 km.range of up to 10,000 km.
LDW 150MLDW 150M
�� Military transport aircraft with capacity of 178 seats and rangeMilitary transport aircraft with capacity of 178 seats and range of up to of up to 12,000 km12,000 km
�� Military equipment and weapons transport aircraft with capacity Military equipment and weapons transport aircraft with capacity of up to of up to 40 tons and range of up to 10,000 km40 tons and range of up to 10,000 km
�� Air refueling tanker with capacity of up to 70 tons of fuel for Air refueling tanker with capacity of up to 70 tons of fuel for refueling refueling purposes and range of up to 5,000 km purposes and range of up to 5,000 km
Accommodation Accommodation –– LDW 150PLDW 150P
�� All versions having 6 backward and 4 All versions having 6 backward and 4 lateral facing folded attendant seatslateral facing folded attendant seats
�� Passenger cabin having downward opening Passenger cabin having downward opening main passenger door on its port side and main passenger door on its port side and opposite service door on its starboard sideopposite service door on its starboard side
�� Two outward opening emergency exit Two outward opening emergency exit doors on the port side and two on the doors on the port side and two on the starboard sidestarboard side
�� Additional two downward rejected Additional two downward rejected emergency exit doors behind passenger emergency exit doors behind passenger cabincabin
�� Two galleys each in front of and behind Two galleys each in front of and behind passenger cabinpassenger cabin
�� Two lavatories in front of passenger cabin, Two lavatories in front of passenger cabin, as well as two each on port and starboard as well as two each on port and starboard side in the backside in the back
Accommodation Accommodation –– LDW 150PLDW 150P ……cont.cont.
�� Two pressurized luggage compartments Two pressurized luggage compartments behind lavatories, each with capacity of behind lavatories, each with capacity of 4.5 m4.5 m³³
�� Two lateral overhead lockable handle Two lateral overhead lockable handle luggage racks over lateral economy seats luggage racks over lateral economy seats 12 m long and 0.9 m deep12 m long and 0.9 m deep
�� Two central overhead lockable handle Two central overhead lockable handle luggage racks 15.5 m long and 0.9 m deepluggage racks 15.5 m long and 0.9 m deep
�� 6+6 side windows in the front of 6+6 side windows in the front of passenger cabinpassenger cabin
�� 11+11 daylight ceiling openings (optional)11+11 daylight ceiling openings (optional)
�� All LDW versions having two separate All LDW versions having two separate lateral cargo and luggage holdslateral cargo and luggage holds
�� 4+4 LD3 containers + 50 m4+4 LD3 containers + 50 m³³ luggage luggage holdsholds
Accommodation Accommodation –– LDW 150FLDW 150F
�� In addition to having lateral/cargo luggage In addition to having lateral/cargo luggage
holds, partially or completely converted holds, partially or completely converted
passenger cabin area being used for cargo passenger cabin area being used for cargo
transport with 4 m wide and 3.2 m long ramptransport with 4 m wide and 3.2 m long ramp
�� Central cargo compartment being 7.14 m wide Central cargo compartment being 7.14 m wide
and 14 m long and 14 m long
�� Cargo volume of 250 mCargo volume of 250 m³³ with constant height of with constant height of
1.9 m1.9 m
Accommodation Accommodation –– LDW 150MLDW 150M
�� MultiMulti--purpose military aircraft for transport of troops purpose military aircraft for transport of troops and equipment, as well as refueling tanker. and equipment, as well as refueling tanker.
�� The biggest difference compared to other versions is The biggest difference compared to other versions is the conversion of outward luggage compartments into the conversion of outward luggage compartments into fuel tanks for a total fuel capacity of 80,000 liters fuel tanks for a total fuel capacity of 80,000 liters (around 21,000 gallons), out of which 70,000 liters are (around 21,000 gallons), out of which 70,000 liters are used for refuelingused for refueling
�� All military versions have a rear cargo ramp for cargo All military versions have a rear cargo ramp for cargo loading and troop embarkationloading and troop embarkation
�� Military transport of up to 178 troops Military transport of up to 178 troops
