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Swashplate

A swashplate, also known as a slant disk, is a mechanical engineering device that translates rotational motion of a shaft into reciprocating motion parallel to the shaft's centerline, or conversely, transmits inputs from a stationary frame to a rotating component.^[1] It typically consists of an angled plate or disk fixed to a rotating shaft, with an outer race or bearing that precesses or tilts to generate linear motion in connected elements such as pistons or linkages.^[1] This mechanism enables precise control and efficient power transmission in various applications, distinguishing it from other motion converters like crankshafts by its ability to produce motion aligned with the rotation axis.^[2] In aeronautics, the swashplate is a critical component of helicopter rotor systems, where it converts pilot control inputs from the non-rotating fuselage into motion for the rotating main rotor blades.^[3] It comprises two primary parts: a stationary swashplate, mounted around the main rotor mast and connected to cyclic and collective controls via pushrods, and a rotating swashplate, which turns with the mast and links to blade pitch horns through pitch links.^[3] By tilting and sliding as a unit, the swashplate adjusts blade pitch cyclically for directional control (roll and pitch) and collectively for altitude changes, allowing stable flight operations.^[3] This design is essential for helicopters ranging from small unmanned aerial vehicles to large transport models, as seen in NASA's Ingenuity Mars helicopter, where the upper swashplate manages rotor pitch via servo motors for flight stability.^[4] Beyond aviation, swashplates find prominent use in hydraulic and pneumatic systems, particularly in axial piston pumps and compressors.^[2] In these devices, the swashplate's angle determines piston stroke length, enabling variable displacement for efficient fluid handling at speeds of 800–4000 rpm.^[2] For instance, in vehicle air conditioning compressors, it drives pistons connected by shoes and a retracting ring, optimizing performance through features like enhanced valve designs that can increase efficiency by up to 12.7%.^[5] Such applications highlight the swashplate's versatility in converting rotary drive into linear force, supporting compact, high-power machinery in industrial and automotive sectors.^[2]

History

Invention by Anthony Michell

Anthony George Maldon Michell (1870–1959) was an Australian mechanical engineer renowned for his innovations in bearings and engines. Born on 21 June 1870 in Islington, London, to Australian parents, he moved to Victoria as a child and graduated from the University of Melbourne with a Bachelor of Civil Engineering in 1895 and a Master of Civil Engineering in 1899.^[6] Michell established himself as a consulting engineer in Melbourne, specializing in hydraulic and mechanical systems, including irrigation and water supply projects. His early career included work on regenerative pumps and a stint as a patent examiner, but he gained prominence through his 1905 invention of the tilting-pad thrust bearing, which addressed axial loads in marine propulsion systems and generated significant royalties by World War I.^[6]^[7] This experience with efficient load distribution in high-thrust applications, such as ship engines, motivated his later designs for balanced power transmission mechanisms.^[8] In 1917, Michell invented the swashplate as a core component of his crankless engine, filing Australian Patent No. 4627 on 19 June for "Improvements in Mechanism for the Transmission of Power." The patent described a tilted "slant disc" mounted obliquely on the drive shaft, which converted the linear reciprocation of pistons in an axial cylinder arrangement into rotary motion, eliminating the traditional crankshaft. This design used slipper pads on the pistons—drawing from his thrust bearing principles—to transfer loads directly to the swashplate via an oil film, avoiding side thrust on the cylinder walls and achieving perfect primary and secondary balance at all speeds.^[9]^[6] The swashplate's oblique plane ensured pure harmonic piston motion, making it suitable for compact, vibration-free axial engines.^[9] Michell secured patents for the crankless engine design in multiple countries, including the United States and United Kingdom, to protect its international application. In the U.S., his mechanism was detailed in Patent US1613116A, granted in 1926 but building on the 1917 Australian filing, which emphasized the swashplate's role in multi-piston coordination for internal combustion cycles. Early prototypes focused on compressors by 1919–1920, with initial internal combustion engine tests following shortly after.^[10]^[9] To commercialize the invention, Michell founded Crankless Engines (Australia) Pty Ltd on 24 August 1920 in Melbourne's Fitzroy suburb, initially as a private company that converted to public status in 1922 with £100,000 capital. The firm established workshops at 129 Greeves Street and built over 45 machines by the mid-1920s, including an 8-cylinder automotive prototype in 1923 (Machine No. 12) and a 70 hp gas engine tested in Sydney around 1923–1924. These early engines demonstrated the swashplate's efficiency in load transfer without side thrust, though commercialization faced challenges from economic pressures.^[11]^[12]^[13]

Development in Engines and Helicopters

Following Anthony Michell's foundational 1917 patent for the swashplate mechanism, its commercialization began in the 1920s with the development of practical engines. In 1927, Michell's eight-cylinder static barrel swashplate engine was produced by the Crankless Engine Company, which he founded in 1920 to exploit the design.^[14] This engine featured pistons acting directly on a tilted swashplate at 22.5 degrees, eliminating the crankshaft and significantly reducing vibration compared to conventional designs.^[15] It found application in marine propulsion, where the low-vibration characteristics were particularly advantageous for shipboard use.^[14] In the 1930s and 1940s, swashplate technology saw further integration into axial internal-combustion engines, building on Michell's axial configuration to enable compact, balanced power delivery.^[14] Concurrently, the mechanism was adapted for Stirling engines, with Philips Research Laboratories initiating swashplate drive concepts in the 1940s to convert reciprocating piston motion into rotation while maintaining sealed, efficient operation.^[16] A notable later revival occurred with Duke Engines' prototypes, which began development in 1993 and demonstrated valveless axial swashplate designs for high power density and torque.^[17] The transition to helicopter applications emerged in the 1940s, drawing from earlier autogyro innovations. Influenced by Igor Sikorsky's rotorcraft designs, the swashplate was incorporated for cyclic and collective pitch control, enabling precise rotor blade angle adjustments.^[18] This culminated in its standard use in post-World War II rotorcraft, such as the Sikorsky R-4 (introduced in 1942), the first production helicopter, which employed a magnesium-alloy swashplate assembly for flight control.^[19] Key milestones included helicopter-specific patents in the 1940s and 1950s, such as Harold F. Pitcairn's 1944 design for rotor pitch control, which was transferred to the U.S. government during World War II and licensed to Sikorsky and Bell.^[20]^[18] By the Korean War era (1950–1953), swashplate-equipped helicopters like the Bell H-13 Sioux and Hiller H-23 Raven were widely adopted by U.S. military forces for evacuation, reconnaissance, and rescue missions, marking the mechanism's maturation in operational aviation.^[21]

Design and Construction

Core Components

The core of a swashplate assembly varies by application but generally consists of an angled disk (the swashplate) fixed to a rotating shaft and a follower interface for connected elements. In axial piston pumps and engines, the swashplate is typically a single rotating plate mounted obliquely to the drive shaft, with piston shoes or slippers maintaining sliding contact on its surface to convert rotation into reciprocating motion.^[2] In helicopter rotor systems, it comprises a rotating swashplate connected to the rotor mast and a stationary swashplate that receives control inputs, with pitch links serving as the follower interface.^[3] Assembly of these components emphasizes precision to ensure smooth operation and minimal friction. Bearings, such as ball or roller types, support rotation and tilting; in variable-displacement designs, they enable angle adjustments, while helicopter configurations use spherical bearings or uniball sleeves between plates to accommodate rotation and prevent metal-to-metal contact.^[2]^[3] Linkages like pushrods connect to actuators in helicopter setups, while general designs may incorporate control mechanisms for angle variation. Centering devices, such as anti-drive links in helicopters or pivots in pumps, maintain alignment during operation.^[3] Materials for swashplate construction prioritize durability under cyclic loading and sliding contact. Steel and aluminum alloys, such as 390-T6 aluminum for plates and 52100 steel for shoes, are commonly used to balance strength, weight, and resistance to wear.^[22] Lubrication points are incorporated at sliding interfaces, like between slippers and the plate surface, to minimize friction and extend component life.^[23] In generic construction, the oblique angle of the swashplate—typically set between 10 and 30 degrees—is established during assembly by mounting the disk at the desired tilt relative to the shaft axis, which directly influences the amplitude of reciprocating motion in connected followers.^[2] This setup ensures reliable motion translation across various mechanical systems, with variations such as dual-plate configurations in helicopter applications adapting the core design for enhanced control.^[3]

Types and Variations

Swashplates in axial piston pumps and engines are primarily categorized into fixed-angle and variable-angle designs. Fixed-angle swashplates feature a constant tilt relative to the cylinder barrel, delivering unchanging piston stroke lengths and thus constant displacement for applications requiring steady hydraulic flow, such as in fixed-displacement axial piston pumps used in medium- to high-pressure systems.^[24]^[25] In contrast, variable-angle swashplates incorporate mechanisms like hydraulic actuators or control pistons to adjust the tilt angle, enabling dynamic variation of piston strokes and output flow from maximum down to near zero, which supports load-adaptive performance in variable-displacement pumps.^[25]^[26] Helicopter swashplates typically employ a dual-plate configuration, consisting of a stationary lower plate linked to flight controls and a rotating upper plate connected via bearings to the rotor mast, allowing coordinated plate movement while accommodating rotation.^[3] A notable variation is the flybarless (FBL) swashplate, which omits the stabilizing flybar in favor of direct electronic servo inputs for precise control, particularly in small-scale unmanned helicopter designs.^[27] Geometric variations in swashplate design, often tailored for remote-controlled (RC) helicopter models, include 90-degree configurations for standard cyclic pitch mixing with aligned servo geometry, 120-degree setups for balanced force distribution across three servos to minimize strain, and 180-degree arrangements for opposed servo placements that simplify mechanical linkages.^[28] These adaptations optimize servo efficiency and control symmetry in compact systems. Additional adaptations encompass single-plate swashplates for basic reciprocating mechanisms in piston engines, where a solitary inclined plate directly drives piston motion without dual elements.^[29] Wobble-plate variants, functioning as single-sided alternatives to conventional swashplates, appear in automotive compressors to generate axial piston reciprocation through a nutating disc rather than a fully rotating one.^[30]

Operating Principles

Motion Conversion Mechanics

The swashplate mechanism converts rotary motion from an input shaft into reciprocating or tilting motion. In axial piston pumps and engines, a stationary oblique disk is mounted at a fixed angle to the shaft via pivots on the housing. As the shaft and attached cylinder barrel rotate, the orbiting pistons, connected via slippers to the tilted swashplate surface, reciprocate axially within their bores due to the plate's inclination, generating linear displacement parallel to the shaft centerline.^[2] This sliding contact at the piston shoes ensures smooth motion proportional to the disk's radius and tilt angle. Multiple pistons arranged around the shaft reciprocate in phase opposition, enabling efficient volume displacement.^[2] In dual-plate configurations, as used in helicopter rotor control, a stationary plate is linked to a rotating oblique plate through bearings, enabling the stationary plate to tilt and transmit angular control inputs to the rotating component while accommodating the shaft's continuous rotation.^[3] For reciprocating motion conversion, the swashplate's tilt imparts axial pushes to pistons, forcing them to extend and retract. Piston shoes, typically featuring ball-and-socket joints, maintain sliding contact with the disk's surface to follow its tilt.^[2] In tilting mechanics, particularly for rotor control, collective inputs raise or lower the entire swashplate assembly along the shaft to uniformly increase or decrease pitch angles across all connected elements, altering overall thrust magnitude. Cyclic inputs, by contrast, tilt the assembly in specific directions, producing differential angles that vary cyclically as the rotating plate spins, thereby directing thrust vector for directional control.^[3] Friction arises at sliding interfaces, such as piston shoes against the swashplate face or bearings between dual plates, necessitating continuous lubrication to reduce energy losses, heat generation, and wear during high-speed operation. Proper lubrication maintains low-friction contact, preserving mechanical efficiency and longevity.^[2]^[1]

Mathematical Modeling

The mathematical modeling of a swashplate focuses on its kinematics, which convert rotational motion into linear reciprocation through the geometry of the tilted disk. The derivation begins with the vector projection of the swashplate's rotation axis onto the piston's axial path. Consider the swashplate tilted at an angle β relative to the perpendicular of the drive shaft axis, with the piston contact point at a radial distance r from the shaft center. As the swashplate rotates by an azimuthal angle ψ (or equivalently, as the barrel rotates relative to a stationary swashplate), the projection of the tilted plane onto the axial direction yields a sinusoidal variation in piston position. Specifically, the instantaneous axial displacement x(ψ) of the piston from its mean position is given by x(ψ) = r tan(β) cos(ψ), where the tan(β) term arises from the slope of the tilted plane, and cos(ψ) captures the harmonic nature of the rotation. This leads to the full axial stroke h, defined as twice the amplitude of the motion, expressed as h = 2 r tan(β).^[31] For small tilt angles (β << 1 rad), tan(β) ≈ β ≈ sin(β), providing a linear approximation commonly used in preliminary design, but the exact form accounts for the oblique geometry without approximation. This model assumes rigid body motion and neglects slipper dynamics or elastic deformations, which are secondary effects in basic kinematics.^[32] In applications requiring variable displacement, such as axial pumps or engines, the stroke h directly influences the swept volume per piston, V = (π d²/4) h, where d is the piston diameter; however, the core kinematic relation remains tied to the tilt angle β for control of output flow or power. For helicopter rotor control, the swashplate's tilt translates pilot inputs into cyclic variations in blade pitch angle. The kinematic relation for the blade pitch θ is θ = θ₀ + A sin(ψ - φ), where θ₀ is the collective pitch angle (uniform across blades), A is the cyclic amplitude determined by the swashplate tilt magnitude, ψ is the rotor azimuth angle, and φ is the control phase angle set by the direction of tilt (e.g., fore-aft or lateral). This equation derives from the swashplate's non-rotating ring displacing pitch links vertically as a function of sin(β) projected onto the rotating frame, producing the sinusoidal pitch variation that tilts the rotor disk for directional control. The amplitude A is proportional to r sin(β) / l, where l is the effective pitch link length, ensuring the pitch change aligns with the tilted thrust vector.^[33] Load analysis on the swashplate incorporates force balances to determine operational torques and stability. The force on each piston is F_piston = P A_piston, where P is the fluid pressure and A_piston is the piston cross-sectional area, representing the primary hydraulic load driving reciprocation. The resulting torque T on the swashplate, which must be counteracted by the control mechanism, is T = ∑ F_piston r cos(β), summing over all pistons with the cos(β) factor accounting for the reduced moment arm due to the tilt (the axial component projects orthogonally to the radius). This torque balance is critical for sizing actuators in variable-displacement systems, as it increases with pressure and decreases with tilt angle, potentially leading to instability if not compensated. In steady-state operation, the net torque is zero when hydraulic forces balance control inputs, derived from equilibrium of moments about the swashplate pivot.^[34]

Applications

In Axial Engines and Pumps

In axial engines, the swashplate serves as a key mechanism for converting the linear reciprocating motion of pistons into rotary motion along the engine's central shaft, eliminating the need for a traditional crankshaft and enabling a more compact layout. This design arranges pistons radially around the shaft in a barrel configuration, allowing for opposed or multi-cylinder setups that balance forces inherently. A seminal example is Anthony Michell's crankless engine, patented in 1922 (US Patent 1,409,057) and prototyped as an eight-cylinder model by 1927, where pistons directly engage a tilted swashplate angled at approximately 22.5 degrees to drive the output shaft.^[14] This configuration supports both internal combustion and Stirling cycle operations, promoting vibration-free performance due to the symmetric piston arrangement and even firing intervals.^[15] Modern implementations, such as those developed by Duke Engines since 1993, further leverage the swashplate in axial prototypes to achieve high power density in valveless, four-stroke designs. These engines feature five cylinders aligned axially, with the swashplate facilitating direct piston-to-shaft motion conversion, resulting in reduced weight, lower vibration, and improved efficiency compared to conventional inline engines.^[17]^[35] Duke's prototypes demonstrate power outputs up to 215 horsepower from a 3-liter displacement while maintaining compact dimensions suitable for automotive and aerospace applications.^[36] In axial piston pumps, the swashplate enables variable displacement by allowing the plate's tilt angle to adjust the pistons' stroke length, thereby controlling fluid flow rate without altering shaft speed. This is particularly useful in hydraulic systems, where pumps like Liebherr's DPVO series use a swashplate design for open-circuit, high-pressure operations up to 420 bar.^[37] The theoretical flow rate Q can be expressed as Q = \left( \frac{\pi D^2}{4} \right) N \sin(\beta) \times Z, where D is the piston bore diameter, N is the rotational speed in revolutions per minute, \beta is the swashplate angle, and Z is the number of pistons; this formula highlights how tilting the swashplate from 0° (zero flow) to its maximum angle scales output up to 100% capacity.^[38] A common application is in automotive air conditioning compressors, such as Toyota's swashplate models, which adjust the plate angle via electromagnetic clutches or hydraulic controls to match cooling demands and optimize fuel efficiency.^[39] Control of the swashplate in these pumps typically involves hydraulic actuators or pressure-compensating mechanisms that respond to system demands, tilting the plate to vary displacement dynamically while minimizing energy loss.^[40] This adaptability makes swashplate axial pumps ideal for heavy machinery and mobile hydraulics, offering stable flow with reduced pulsation compared to fixed-displacement alternatives.^[37]

In Helicopters

In helicopters, the swashplate serves as the primary mechanism for translating pilot control inputs into changes in main rotor blade pitch, enabling precise flight control in rotorcraft such as single-rotor configurations.^[3] It consists of a stationary lower plate mounted around the main rotor mast, which receives inputs from the cyclic and collective controls via pushrods and mixing units or servos, and an upper rotating plate connected to the blade pitch horns through pitch links.^[3] This design allows for continuous 360-degree cyclic control without mechanical interference between the stationary inputs and the rotating rotor system.^[41] The collective pitch function is achieved through vertical translation of the entire swashplate assembly along the rotor mast, which uniformly adjusts the pitch angle of all main rotor blades to vary overall lift and enable altitude control.^[3] This upward or downward movement, driven by the collective lever, increases or decreases thrust symmetrically across the rotor disk.^[42] Cyclic pitch control involves tilting the swashplate in the desired direction, which cyclically varies the blade pitch angles as the rotor rotates, creating a differential lift between the advancing and retreating blades to tilt the rotor disk and provide directional control in roll and pitch.^[41] Yaw control is typically managed separately via the tail rotor, but the swashplate's cyclic tilting contributes to overall attitude stability.^[3] The swashplate mechanism became standard in single-rotor helicopters following its adoption in designs during the 1940s.^[43] A prominent example is the Bell UH-1 Iroquois, introduced in the 1960s, where the swashplate integrates with hydraulic servos for collective and cyclic inputs to support utility and transport missions.^[44] In radio-controlled (RC) model helicopters, cyclic-collective-pitch-mixing (CCPM) configurations use three non-orthogonal servos linked to the swashplate to simultaneously handle cyclic and collective commands, reducing servo load and improving control efficiency.^[45]

Other Uses

Beyond their primary roles in engines, pumps, and rotorcraft, swashplates find application in specialized systems for motion control and fluid handling. In active electronically scanned array (AESA) radars, a mechanical swashplate mechanism tilts the antenna array to enable wide-angle beam steering, achieving up to a 200° field of regard with a 40° plate tilt angle.^[46] This hybrid approach combines electronic beamforming with mechanical repositioning, reducing the need for extensive electronic phase shifters in military phased-array systems like the Eurofighter Typhoon's ECRS Mk 2 radar, thereby enhancing scan coverage and operational flexibility. As of September 2024, the ECRS Mk 2 radar featuring a swashplate mechanism achieved its first flight on a Eurofighter Typhoon testbed, demonstrating advanced beam steering capabilities.^[46]^[47] In multistage air compressors, swashplate designs facilitate high-pressure gas compression across multiple cylinders of varying sizes, with the plate's adjustable angle enabling variable displacement to optimize output based on demand.^[48] This adjustment alters piston stroke length, allowing control over refrigerant or air flow while adhering to the first law of thermodynamics for work done on the gas during compression cycles.^[39] Such compressors are commonly used in automotive air conditioning systems, where they maintain efficient cooling by modulating capacity without a clutch.^[39] Emerging applications include robotic actuators, where swashplates provide precise control over reciprocating linear motion in displacement-controlled hydraulic systems, offering energy efficiency and high accuracy for manipulators.^[49] Prototypes have explored swashplate integration in automotive variable valve timing mechanisms to enable dynamic adjustment of valve lift and duration in axial piston configurations.^[50] Niche implementations appear in floating cup pumps for high-pressure hydraulics, featuring swashplate-mounted cup elements that pair with pistons equipped with dual sealing rings to minimize leakage under extreme pressures up to 450 bar (continuous) or 500 bar (peak).^[51] These designs, often with spherical piston heads forming tight seals against the floating cups, excel in compact, high-efficiency fluid power systems for industrial and mobile equipment.^[52]

Advantages and Disadvantages

Benefits

Swashplate designs offer significant compactness and high power density due to their axial arrangement, which aligns pistons parallel to the output shaft, reducing overall volume compared to traditional crankshaft mechanisms in engines and pumps. This configuration enables a smaller footprint, making it suitable for space-constrained applications such as heavy machinery and aerospace systems.^[53] In axial piston pumps, the swashplate's structure supports high power-to-weight ratios, allowing efficient operation under demanding conditions like construction equipment.^[54] The balanced forces in swashplate mechanisms minimize vibrations and noise, as the axial layout reduces side loads and harmonics that are common in offset piston designs. This attribute is particularly beneficial in marine applications, where Michell crankless engines utilized swashplates to eliminate vibration inherent in crankshaft systems, enhancing durability in ship propulsion.^[15] Similarly, in automotive air conditioning compressors, the swashplate's smooth reciprocation lowers operational noise, improving passenger comfort and meeting regulatory standards.^[55]^[56] Adjustability is a key advantage, with the variable swashplate angle enabling precise control of displacement from 0% to 100% without throttling, which optimizes efficiency across load ranges. In hydraulic pumps, this allows for seamless adaptation to varying flow and pressure demands, achieving up to 10-15% energy savings in partial-load operations compared to fixed-displacement alternatives.^[54]^[53] In radar systems employing mechanical steering, swashplate-based arrays provide extended scan ranges over purely electronic methods by enabling lightweight, compact beam tilting with reduced failure risk.^[57]

Limitations

Swashplate systems in axial piston pumps and helicopter rotors are prone to wear due to high sliding contact between components such as piston shoes and the swashplate surface, where three-body abrasive wear predominates from contamination particles in the lubricant.^[58] This wear is exacerbated in low-viscosity fluids, as insufficient hydrodynamic lubrication fails to maintain an adequate oil film thickness, leading to direct metal-to-metal contact and potential slipper burning.^[59] In pumps, the required oil film is governed by principles like the Reynolds equation, which models pressure distribution to predict minimum film thickness under varying loads and speeds, but deviations from optimal conditions accelerate friction and degradation. The mechanical complexity of swashplate assemblies, involving dual plates connected by bearings and multiple actuators, significantly increases the parts count and elevates failure risks, particularly in helicopter applications where exposed linkages contribute to drag and maintenance demands.^[60] Common failure modes include bearing deformation from uneven loads and actuator faults that disrupt pitch control, necessitating robust condition monitoring to detect early wear in swashplate components.^[61] Variable swashplate angles impose stringent containment requirements, as axial loads from piston forces or rotor thrust can destabilize the plate without adequate housing support, potentially leading to misalignment or catastrophic failure.^[62] In designs employing secondary swashplates for enhanced control, the housing must counteract these forces to maintain stability across the operational tilt range, often requiring reinforced structures to prevent axial play under high-pressure conditions in pumps.^[62] Performance limitations of swashplate systems include reduced efficiency in pumps when operating with high-viscosity fluids exceeding typical thresholds (e.g., above 150 cSt), where increased viscous friction between slippers and the plate elevates energy losses and lowers delivery rates.^[63] Additionally, the maximum tilt angle is constrained to approximately 30 degrees in most axial piston pumps and helicopter rotors, limiting applications requiring extreme angular displacements, such as advanced scanning mechanisms in radar systems.^[64] To mitigate these challenges, engineering solutions incorporate advanced materials like fiber-reinforced epoxy composites for swashplates, which reduce weight and improve fatigue resistance while lowering overall system inertia in helicopters.^[65] In flybarless (FBL) helicopters, digital controls enhance precision by electronically stabilizing swashplate inputs, compensating for mechanical tolerances and reducing failure risks through real-time adjustments.^[27] Hybrid electro-mechanical designs further address limitations by integrating electronic actuators with traditional plates, offering fault-tolerant operation and reduced mechanical complexity in actuation systems.^[66]

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Multi-parameter load sensing pump model simulation and flow rate ...
Accordingly, the torque balance equation of the swash plate can be expressed in the form below:(10) p c A p cos θ p r - k p x p cos θ p + F po r - M sw + M pl + ...
[37]
Duke Engines' incredibly compact, lightweight valveless axial engine
Sep 3, 2014 · It's the smallest and lightest engine around for its displacement and power output. "Even our prototypes are outperforming established engines ...Missing: 1993 | Show results with:1993
[38]
The Valveless Duke Axial Engine Is Lighter, More Compact, & More ...
Dec 19, 2014 · The 3-liter, five cylinder Duke Axial Engine utilizes an innovative valveless ported design in order to crank out 215 horsepower and 250 lb-ft ...
[39]
Variable displacement pump DPVO - Liebherr
The variable displacement axial piston pumps DPVO are of swash plate design and built for open circuit and high-pressure applications.
[40]
"Kinematic analysis of a swash-plate controlled variable ...
Jan 1, 2010 · Variable displacement, swash-plate controlled, axial-piston pumps are widely used in applications that require high pressure and variable flow ...
[41]
Types of Compressor and Structure - Toyota Industries Corporation
The swash plate angle can be adjusted, which forces the piston to make larger or smaller strokes. This enables stable temperature control and improved driving ...
[42]
The Basics Of Variable Displacement Pump Controls - CrossCo
Sep 2, 2016 · In a variable displacement pump, we vary the angle of the rotating group, which is done by tilting the swash plate. Pressure Compensation – ...
[43]
[PDF] Active Helicopter Rotor Control Using Blade-Mounted Actuators
Tilting the swashplate generates cyclic commands which vary the blade pitch angle sinusoidally with a period of one rotor revolution. This effectively tilts the ...<|control11|><|separator|>
[44]
[PDF] The Cierva Autodynamic Rotor
Means to control rotor collective pitch with applied torque or a swashplate. 2,296,251 23 August. 1940 (USA). 1 December. 1938 (UK). 22 September. 1942 (USA).<|separator|>
[45]
Helicopters & Vertical Flight – Introduction to ... - Eagle Pubs
The helicopter's control surfaces, including the swashplate, pedals, and collective, enable control over the helicopter's direction and altitude. This makes a ...
[46]
[PDF] Model development, system identification, and control of a quadrotor ...
... rotor having separate collective pitch actuation. This is the most common helicopter architecture, with examples such as the Bell UH-1 Iroquois. (Huey), ...
[47]
[PDF] Autonomous Helicopter Aerobatics through Apprenticeship Learning
Jun 23, 2010 · pitch mixing (CCPM) where three non-orthogonal servos are used to control both the cyclic pitch and collective pitch together, rather than ...
[48]
British Eurofighter Finally Gets Advanced Swashplate AESA Radar
Jan 17, 2024 · In comparison with traditional mechanically scanned array technology, an AESA can find and track a target at a much greater range, more quickly, ...Missing: beam steering
[49]
Optimization of swash plate multistage compressor based on ...
The swash plate compressor can provide high-pressure gas through multistage compression using its different cylinders, which is an ideal structure for ...Missing: ratio | Show results with:ratio
[50]
An Investigation of Swash Plate Control Concepts for Displacement ...
Aug 7, 2025 · This study proposes an energy-efficient and high-precision closed-loop controller for the highly nonlinear hydraulic robotic manipulators.
[51]
The Potential of Wobble Plate Opposed Piston Axial Engines ... - MDPI
In an engine with a wobble plate mechanism, the problem of torsional vibrations is significantly reduced. The gas and inertia forces are first transferred to ...
[52]
Floating cup pump having swashplate mounted cup elements
A floating cup pump assembly incorporating a tilted swashplate structure with cup elements projecting away from either side of the swashplate structure.
[53]
Floating Cup - Innas BV
The Floating Cup uses cup-like cylinders that 'float' on a rotating plate, paired with pistons, and is designed for high efficiency and performance.Missing: rings | Show results with:rings
[54]
News - What Are the Advantages of a Swash Plate axial Piston Pump?
Compared with other types of hydraulic pumps, the swash plate axial piston pump can significantly reduce oil leakage, reduce system pressure loss and energy ...
[55]
[PDF] Swash plate pumps – the key to the future - Qucosa - TU Dresden
The advantages of axial piston pumps with swash plate design is the high nominal pressure level, variability of the displacement, beneficial efficiencies ...
[56]
Swash Plate Type Axial Piston Hydraulic Pump - News
Feb 23, 2022 · The Swash Plate Type Axial Piston Hydraulic Pump operates on the principle of converting mechanical energy into hydraulic energy through the ...<|control11|><|separator|>
[57]
Variable-displacement Swash Plate Compressors - ZonCen
By adjusting the angle of the swash plate, the compressor can modulate its displacement, thereby regulating the flow of refrigerant and maintaining optimal ...Missing: compression ratio
[58]
Cyclic/Collective Pitch Mixing - Edward McFarlane
Dec 14, 2020 · This technique is known a cyclic/collective pitch mixing (CCPM). With CCPM we can reduce the complexity of the swash plate whilst improving ...Missing: benefits strain
[59]
What is CCPM on RC Helicopters & How To Identify Swashplate Types
With 140°mixing, the swashplate geometry is evened out between the side servos and the front or back servo.Missing: dual credible engineering sources
[60]
Mechanical swash plate array versus digitaly steered array! - Key Aero
A swash plate array (as proposed for Gripen and Typhoon, at any rate) is a normal AESA, just mounted on a mechanically steerable platform rather than fixed to ...
[61]
Multi technical analysis of wear mechanisms in axial piston pumps
Jun 19, 2025 · The observations reveal that in the contact between shoes and swashplate, the main wear mechanism is three-body abrasive wear due to coarse ...
[62]
Study on the Lubricating Characteristics of the Oil Film of the Slipper ...
Dec 8, 2023 · The oil film cannot be too thin or too thick; too thin will cause excessive wear and slipper burning damage, and too thick will have a small ...
[63]
Rotorcraft Aeromechanics - Dr. Inderjit Chopra - University of Maryland
The swashplate assembly is heavy, complex and maintenance intensive. In addition, the exposed linkages result in a large drag penalty during forward flight.Missing: modes | Show results with:modes
[64]
[PDF] Detection of CH-53 swashplate bearing deformation - PHM Society
Therefore the swashplate bearings are safety of flight critical components. ... The rotating plate transmits the load through the bearings to the stationary plate ...<|separator|>
[65]
The control and containment forces on the swash plate of an axial ...
Aug 7, 2025 · In this research, it is shown that the secondary swash-plate angle has a significant impact on the problem of swash-plate control and ...Missing: viscosity | Show results with:viscosity
[66]
Effect of Operating Parameters on Efficiency of Swash-Plate Type ...
This study presents the performance measurement results of a variable displacement axial piston pump in the form of efficiencies as a function of pressure, ...
[67]
Understanding the Mechanics of a Hydraulic Piston Pump
Jul 26, 2024 · Swash Plate (in axial piston pumps): A swash plate tilts pistons so they go up and down instead of round and round, changing how much liquid is ...<|separator|>
[68]
US4804315A - Composite helicopter swashplate - Google Patents
The field of art to which this invention pertains is helicopter swashplates and particularly swashplates comprising fiber reinforced epoxy matrix composite.
[69]
System-level modeling and preliminary experiment study of a ...
Oct 22, 2025 · The Helicopter Electro-Mechanical Actuation System project has not yet led to mature solutions. In contrast, EHA has achieved widespread ...<|control11|><|separator|>