CN105620727B - A kind of low noise unmanned plane rotor/propeller - Google Patents
A kind of low noise unmanned plane rotor/propeller Download PDFInfo
- Publication number
- CN105620727B CN105620727B CN201610063152.5A CN201610063152A CN105620727B CN 105620727 B CN105620727 B CN 105620727B CN 201610063152 A CN201610063152 A CN 201610063152A CN 105620727 B CN105620727 B CN 105620727B
- Authority
- CN
- China
- Prior art keywords
- unmanned plane
- value
- blade
- propeller
- low noise
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
- B64C11/16—Blades
- B64C11/18—Aerodynamic features
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
- B64C11/16—Blades
- B64C11/20—Constructional features
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C27/00—Rotorcraft; Rotors peculiar thereto
- B64C27/32—Rotors
- B64C27/46—Blades
- B64C27/463—Blade tips
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
- B64U10/00—Type of UAV
- B64U10/25—Fixed-wing aircraft
Landscapes
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Remote Sensing (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
The present invention provides a kind of low noise unmanned plane rotor/propeller, including blade, the leading edge of the blade is sinuous nodular structure, the trailing edge of the blade is the broached-tooth design of isosceles triangle shape, microarray diaphragm structure is bonded with the wing tip suction surface of the blade, the microarray diaphragm structure is made up of substrate and the equally distributed some flexible columns being arranged on substrate.The present invention proposes a kind of practical and economic and environment-friendly blade design structure, the noise of unmanned plane rotor/propeller is reduced to a certain extent, it disclosure satisfy that particular/special requirement of the different occasions to unmanned plane noise level, improve the efficiency of unmanned plane, make the endurance of unmanned plane be strengthened, more energy-conserving and environment-protective, there is economic implications.
Description
Technical field
The present invention relates to unmanned plane rotor/propeller noise reduction technology field, specifically a kind of low noise unmanned plane rotor/spiral shell
Revolve oar.
Background technology
Today's society, more and more occasions visible its figure, as military affairs detect more and more progressive with the technology of unmanned plane
Examine, assist anti-terrorism etc., unmanned plane has played great role, reduces unnecessary loss and improves success rate.But some
In the case of, its noise problem brings hidden danger to its security, is found and fallen event as unmanned plane occurs for military surveillance.
The reason for unmanned plane is found its low-latitude flying, small volume, is not easy largely precisely due to it has bigger noise
Found by radar, but noise governs its security.For problems, present countries in the world all start one research low noise
The upsurge of unmanned plane.
In general, the reduction of noise has two methods：Active noise reduction and passive noise reduction.Active noise reduction is primarily referred to as using phase
Dry sound wave offsets existing noise field, suppresses to produce the vibration source of noise.The units such as domestic Nanjing University's acoustics institute, utilize this
Method realizes active noise reduction, and experiment effect clearly, but is at the laboratory research stage, does not reach practical journey far
Degree.When in face of complex sound field of the unmanned plane rotor/propeller in spatial distribution, this mode more seems helpless.It is so-called
Passive noise reduction mainly include with sound absorption structure by the mechanical energy of incident acoustic wave be converted into the other forms such as heat energy energy or
Modify its external structure so that fluid more adsorbs its surface, reduces fluid separation and comes off, so as to reduce the generation of noise.Pin
To the situation of unmanned plane rotor/propeller quick rotation in space, also it is difficult to reach the target of noise reduction using sound absorption structure
Carry out.It is finally feasible for it to be exactly how research by modifying the space structure of unmanned plane rotor/propeller reaches noise reduction
Purpose.
The content of the invention
It is an object of the invention to provide a kind of low noise unmanned plane rotor/propeller, can obtain effective noise reduction effect
Fruit, it is practical, it is economic and environment-friendly.
The technical scheme is that：
A kind of low noise unmanned plane rotor/propeller, including blade, the leading edge of the blade is sinuous tubercle knot
Structure, the trailing edge of the blade are the broached-tooth design of isosceles triangle shape, and microarray is bonded with the wing tip suction surface of the blade
Diaphragm structure, the microarray diaphragm structure are made up of substrate and the equally distributed some flexible columns being arranged on substrate.
Described low noise unmanned plane rotor/propeller, the nodular structure are made up of several tubercles, the tubercle
Height value is 0.005L~0.2L, and the width value of the tubercle is 3mm~30mm, the number value of the tubercle for 2~
20；Wherein, L represent single paddle mean chord, its value for single paddle horizontal projected area and the span ratio, its
Unit is mm.
Described low noise unmanned plane rotor/propeller, the broached-tooth design are made up of several sawtooth, the sawtooth
Height value is 0.01L~0.4L, and the width value of the sawtooth is 0.01L~0.5L, the number value of the sawtooth for 3~
50；Wherein, L represent single paddle mean chord, its value for single paddle horizontal projected area and the span ratio, its
Unit is mm.
Described low noise unmanned plane rotor/propeller, the height value of the flexible column is 0.01%L~30%L, described
The basal diameter value of flexible column is 0.1 ‰ L~30%L, distribution density value of the flexible column on substrate be 0.5%~
20%；Wherein, L represent single paddle mean chord, its value for single paddle horizontal projected area and the span ratio,
Its unit is mm.
Beneficial effects of the present invention are：
（1）For the complexity of unmanned plane rotor/propeller noise, the present invention proposes a kind of practical and economic ring
The blade design structure of guarantor, the noise of unmanned plane rotor/propeller is reduced to a certain extent, disclosure satisfy that different occasions pair
The particular/special requirement of unmanned plane noise level.
（2）The present invention is to copy the cat head in nature with " Jing Yin " flight characteristics based on bionical denoising structure is coupled
Hawk structure is got, it is possible to increase the efficiency of unmanned plane, make the endurance of unmanned plane be strengthened, more energy-conserving and environment-protective, and tool
There is economic implications.Although research object of the present invention is to be directed to unmanned plane rotor/propeller, as fan, axial flow blower, turbine
The rotating machineries such as machine can use leading edge nodular structure, trailing edge broached-tooth design and wing tip suction surface microarray diaphragm structure this three
One or more in kind structure, can be used alone or be applied in combination, and can also be used to the aerodynamic noise for solving aircraft
Problem.
（3）The present invention gives the span of above-mentioned three kinds of structural parameters, this chi to concrete structure in practical application
Very little selection has directive significance.
（4）Above-mentioned three kinds of structures proposed by the present invention in addition to being fixed to integration with blade can be made into that energy can be torn open
Dress it is movable, to be used according to actual conditions, or even with control system be combined to form active noise reduction system.
Brief description of the drawings
Fig. 1 is the structural representation of the present invention；
Fig. 2 is Fig. 1 A portions enlarged drawing；
Fig. 3 is Fig. 1 B portions enlarged drawing；
Fig. 4 is Fig. 1 C portions enlarged drawing.
Embodiment
Below in conjunction with the accompanying drawings the present invention is further illustrated with specific embodiment.
As shown in Figure 1 to 4, a kind of low noise unmanned plane rotor/propeller, including blade 1, the leading edge 11 of blade 1 are adopted
With sinuous nodular structure, the trailing edge 12 of blade 1 is using the broached-tooth design of isosceles triangle shape, the wing tip suction of blade 1
Microarray diaphragm structure 2 is bonded with face, wherein, microarray diaphragm structure 2 is by substrate and is arranged on uniformly dividing on substrate
Some flexible columns 21 of cloth are formed.
The major parameter of nodular structure includes tubercle height a, tubercle width b, node number M, after these three parameter optimizations
Span it is as follows：
Tubercle height a values are in 0.005L~0.2L；
Tubercle width b values are in 3mm~30mm；
Node number M values are 2~20.
The major parameter of broached-tooth design includes sawtooth height c, tooth width d, sawtooth number N, after these three parameter optimizations
Span it is as follows：
Sawtooth height c values are in 0.01L~0.4L；
Tooth width d values are in 0.01L~0.5L；
Sawtooth number N value is 3~50.
The microarray diaphragm structure 2 pasted on wing tip suction surface be using MEMS technology process circular silicon column hole array or
Person's nickel post holes array mould plate, then by pouring simultaneously spin coating PDMS flexible materials, what curing and demolding obtained.Wherein, silicon column hole or
The height or diameter of nickel post holes are the height and diameter of the single flexible post 21 of microarray diaphragm structure 2.
Below by taking the making of silicon column pore array template as an example, lower technical process is introduced, 3 inch silicon wafers is chosen and is used for making silicon
Post holes array mould plate, it is as follows using L-Edit software development mask plate patterns, specific preparation flow：
（1）It is from 3 inches of diameter, crystal orientation（100）Single-sided polishing silicon chip, thickness be 500 microns, then to monocrystalline throw
Light silicon chip carries out Chemical cleaning, rear drying process；
（2）The silica membrane and 200 of 600 nanometer thickness of growth deposition is received successively on the burnishing surface of monocrystalline polished silicon slice
The thick metal aluminium film of rice；
（3）The photoresist that a layer thickness is 2 microns is coated in metal aluminium film（Positive photoresist）；
（4）Front photolithography plate mask exposure；
（5）Development, it is fixed；
（6）The corrosion window of front side aluminum is opened；
（7）The corrosion window of front silica is opened；
（8）Erosion removal front photoresist；
（9）Using inductively coupled plasma（ICP）Deep etching process etches silicon at corrosion window to the depth designed
Degree, etch the monocrystalline silicon of no metallic aluminium mask pattern and earth silicon mask figure protection zone, until required depth with
Obtain the silicon column hole array for meeting design；
（10）Remove front metal aluminium mask layer；
（11）Remove positive silicon dioxide mask layer；
（12）One layer is made containing fluorine-based compound on silicon column hole array surface using spraying process, to reduce its adhesiveness.
Because silicon column hole array aperture is smaller, hole depth is larger, and the density of array is high, between silicon column hole array and PDMS because
Adhesion is very big caused by contact area is big, if do not pre-processed to silicon column pore array template, easily causes PDMS to take off
It is damaged after mould, or even be difficult to be stripped.It is therefore possible to use spraying process is in one layer of ultra-thin fluorine class of silicon column hole array surface spraying
Compound, its adhesiveness is reduced, in order to which PDMS is stripped from silicon column pore array template.
Height h, basal diameter Φ and the flexible column 21 that the major parameter of microarray diaphragm structure 2 includes flexible column 21 exist
Distribution density ρ on substrate, wherein, distribution density ρ of the flexible column 21 on substrate refers to all flexible columns 21 on substrate
The ratio of floor space sum and chip area, the span after these three parameter optimizations are as follows：
The height h values of flexible column 21 are in 0.01%L~30%L；
The basal diameter Φ values of flexible column 21 are in 0.1 ‰ L~30%L；
Distribution density ρ value of the flexible column 21 on substrate is 0.5%~20%.
Above-mentioned L represents the mean chord of single paddle 1, and its value is horizontal projected area and the span of single paddle 1
Ratio, unit：mm.
Some biologies pass through the evolution of 1 years in nature, form the somatic stigmata with environmental suitability, such as cat
The Jing Yin flight characteristics of head hawk is exactly Typical Representative therein.The present invention is inspired by " Jing Yin " flight of cat owl, with reference to coupling
Bionic theoretical foundation, design and made leading edge nodular structure, trailing edge broached-tooth design and wing tip suction surface microarray diaphragm
The blade of structure Coupling, and the preferable parameter combination of effect is obtained by experimental study.
Effect of these three structures played in unmanned plane rotor/propeller noise reduction differs, leading edge nodular structure
The momentum of downstream direction vortex is mainly improved, increases its adhesive force, delays to separate, to suppressing noise while improving lift
Have certain effect；Trailing edge broached-tooth design make it that the radiated noise of unmanned plane rotor/propeller trailing edge is further reduced；The wing
Sharp suction surface microarray diaphragm structure is set according to the flow behavior of the fluid on suction surface so that the fluid energy of modified
It is enough gently to flow to trailing edge, vortex is reduced in a way to come off caused noise.
These three structures difference can be used alone in different objects, or combination of two according to the actual requirements（Leading edge knot
Nodule structure couples with trailing edge broached-tooth design, leading edge nodular structure couples with wing tip suction surface microarray diaphragm structure, trailing edge sawtooth
Structure couples with wing tip suction surface microarray diaphragm structure）, all can effectively reduce aerodynamic noise.
The results show, using unmanned plane rotor/propeller of coupling biomimetic features, its noise reduction is more obvious,
This greatly improves " Jing Yin " performance of unmanned plane, the security performance of unmanned plane has been ensured to a certain extent.
The coupling biomimetic features of the present invention have portability, and in addition to unmanned plane, can be also used for other needs to drop
The rotating machinery made an uproar, such as axial flow blower, fan, turbomachinery, it can effectively reduce aerodynamic noise.
Embodiment described above is only that the preferred embodiment of the present invention is described, not to the model of the present invention
Enclose and be defined, on the premise of design spirit of the present invention is not departed from, technical side of the those of ordinary skill in the art to the present invention
The various modifications and improvement that case is made, it all should fall into the protection domain of claims of the present invention determination.
Claims (4)
1. a kind of low noise unmanned plane rotor/propeller, including blade, it is characterised in that：The leading edge of the blade is sine wave
The nodular structure of shape, the trailing edge of the blade are the broached-tooth design of isosceles triangle shape, are glued on the wing tip suction surface of the blade
Microarray diaphragm structure is connected to, the microarray diaphragm structure is by substrate and is arranged on equally distributed some soft on substrate
Property post form.
2. low noise unmanned plane rotor/propeller according to claim 1, it is characterised in that：If the nodular structure by
Dry tubercle is formed, and the height value of the tubercle is 0.005L~0.2L, and the width value of the tubercle is 3mm~30mm,
The number value of the tubercle is 2~20；Wherein, L represents the mean chord of single paddle, and its value is the level of single paddle
Projected area and the ratio of the span, its unit are mm.
3. low noise unmanned plane rotor/propeller according to claim 1, it is characterised in that：If the broached-tooth design by
Dry sawtooth is formed, and the height value of the sawtooth is 0.01L~0.4L, and the width value of the sawtooth is 0.01L~0.5L,
The number value of the sawtooth is 3~50；Wherein, L represents the mean chord of single paddle, and its value is the level of single paddle
Projected area and the ratio of the span, its unit are mm.
4. low noise unmanned plane rotor/propeller according to claim 1, it is characterised in that：The height of the flexible column
Value is 0.01%L~30%L, and the basal diameter value of the flexible column is 0.1 ‰ L~30%L, and the flexible column is on substrate
Distribution density value be 0.5%~20%；Wherein, L represents the mean chord of single paddle, and its value is the level of single paddle
Projected area and the ratio of the span, its unit are mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610063152.5A CN105620727B (en) | 2016-01-30 | 2016-01-30 | A kind of low noise unmanned plane rotor/propeller |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610063152.5A CN105620727B (en) | 2016-01-30 | 2016-01-30 | A kind of low noise unmanned plane rotor/propeller |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105620727A CN105620727A (en) | 2016-06-01 |
| CN105620727B true CN105620727B (en) | 2018-03-20 |
Family
ID=56036159
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610063152.5A Expired - Fee Related CN105620727B (en) | 2016-01-30 | 2016-01-30 | A kind of low noise unmanned plane rotor/propeller |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105620727B (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10011346B2 (en) | 2015-12-18 | 2018-07-03 | Amazon Technologies, Inc. | Propeller blade indentations for improved aerodynamic performance and sound control |
| US10099773B2 (en) | 2015-12-18 | 2018-10-16 | Amazon Technologies, Inc. | Propeller blade leading edge serrations for improved sound control |
| US10259562B2 (en) | 2015-12-18 | 2019-04-16 | Amazon Technologies, Inc. | Propeller blade trailing edge fringes for improved sound control |
| JP6643480B2 (en) * | 2015-12-18 | 2020-02-12 | アマゾン テクノロジーズ インコーポレイテッド | Propeller blade machining for acoustic control |
| US10460717B2 (en) | 2015-12-18 | 2019-10-29 | Amazon Technologies, Inc. | Carbon nanotube transducers on propeller blades for sound control |
| US10933988B2 (en) | 2015-12-18 | 2021-03-02 | Amazon Technologies, Inc. | Propeller blade treatments for sound control |
| US10259574B2 (en) | 2015-12-18 | 2019-04-16 | Amazon Technologies, Inc. | Propeller surface area treatments for sound dampening |
| CN106114850B (en) * | 2016-06-23 | 2018-08-21 | 湖北大秀天域科技发展有限公司 | A kind of mute blade and the rotor wing unmanned aerial vehicle containing it |
| CN106275423A (en) * | 2016-08-23 | 2017-01-04 | 成都翼高九天科技有限公司 | A kind of novel unmanned plane rotor aerodynamics structure |
| US10604245B2 (en) * | 2016-12-30 | 2020-03-31 | Wing Aviation Llc | Rotor units having asymmetric rotor blades |
| CN107074344B (en) * | 2017-01-13 | 2018-09-25 | 深圳市大疆创新科技有限公司 | Propeller, power suit and the unmanned plane of aircraft |
| WO2018206860A1 (en) * | 2017-05-11 | 2018-11-15 | Jose Buendia | Optimized helicopter - aeroplane - wing- propeller/rotor profiles |
| US11163302B2 (en) | 2018-09-06 | 2021-11-02 | Amazon Technologies, Inc. | Aerial vehicle propellers having variable force-torque ratios |
| CN109356802B (en) * | 2018-12-29 | 2019-10-01 | 南京航空航天大学 | A kind of pneumatic equipment bladess with denoising structure |
| CN110429158A (en) * | 2019-07-04 | 2019-11-08 | 云南师范大学 | The wet etching method of non-refrigerated infrared focal plane probe optical window |
| CN110466751A (en) * | 2019-09-03 | 2019-11-19 | 中国科学院合肥物质科学研究院 | A kind of the high effective portable unmanned plane rotor structure and its design method of low noise |
| CN112896503B (en) * | 2021-03-18 | 2022-12-13 | 厦门大学 | Helicopter rotor blade capable of restraining tip vortex of blade |
| CN113086169B (en) * | 2021-03-30 | 2022-07-12 | 吉林大学 | Bionic propeller capable of reducing drag and noise and preparation method thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5088665A (en) * | 1989-10-31 | 1992-02-18 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Serrated trailing edges for improving lift and drag characteristics of lifting surfaces |
| CN1110368A (en) * | 1993-11-04 | 1995-10-18 | 斯道克产品工程公司 | Wind turbine |
| CN102162464A (en) * | 2011-05-05 | 2011-08-24 | 广东志高空调有限公司 | Cross flow wind wheel of sawtooth-type vanes with pits |
| CN203584893U (en) * | 2013-12-09 | 2014-05-07 | 深圳市锦固鸿五金科技有限公司 | Noise-reduction energy-saving fan |
| CN104064175A (en) * | 2014-07-10 | 2014-09-24 | 中国科学院电子学研究所 | Bionic noise-reduction membrane |
| CN205418069U (en) * | 2016-01-30 | 2016-08-03 | 中国科学院合肥物质科学研究院 | Low noise unmanned aerial vehicle rotor / screw |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7059833B2 (en) * | 2001-11-26 | 2006-06-13 | Bonus Energy A/S | Method for improvement of the efficiency of a wind turbine rotor |
-
2016
- 2016-01-30 CN CN201610063152.5A patent/CN105620727B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5088665A (en) * | 1989-10-31 | 1992-02-18 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Serrated trailing edges for improving lift and drag characteristics of lifting surfaces |
| CN1110368A (en) * | 1993-11-04 | 1995-10-18 | 斯道克产品工程公司 | Wind turbine |
| CN102162464A (en) * | 2011-05-05 | 2011-08-24 | 广东志高空调有限公司 | Cross flow wind wheel of sawtooth-type vanes with pits |
| CN203584893U (en) * | 2013-12-09 | 2014-05-07 | 深圳市锦固鸿五金科技有限公司 | Noise-reduction energy-saving fan |
| CN104064175A (en) * | 2014-07-10 | 2014-09-24 | 中国科学院电子学研究所 | Bionic noise-reduction membrane |
| CN205418069U (en) * | 2016-01-30 | 2016-08-03 | 中国科学院合肥物质科学研究院 | Low noise unmanned aerial vehicle rotor / screw |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105620727A (en) | 2016-06-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105620727B (en) | A kind of low noise unmanned plane rotor/propeller | |
| CN205418069U (en) | Low noise unmanned aerial vehicle rotor / screw | |
| Lei et al. | Three-dimensional Improved Delayed Detached Eddy Simulation of a two-bladed vertical axis wind turbine | |
| Clark et al. | Bioinspired trailing-edge noise control | |
| US20200018285A1 (en) | Airfoil with a vortex generator pair | |
| CN101917784B (en) | Three-dimensional micro heater with groove-shaped heating film region and manufacturing method thereof | |
| US8783337B2 (en) | System for changing the convective heat transfer coefficient for a surface | |
| CN201461226U (en) | Vane | |
| Le et al. | Morphological effect of a scallop shell on a flapping-type tidal stream generator | |
| Genç et al. | Traditional and new types of passive flow control techniques to pave the way for high maneuverability and low structural weight for UAVs and MAVs | |
| Noda et al. | Development of bio-inspired low-noise propeller for a drone | |
| CN101296842A (en) | Plasma actuators for drag reduction on wings, nacelles and/or fuselage of vertical take-off and landing aircraft | |
| Finez et al. | Broadband noise reduction of linear cascades with trailing edge serrations | |
| Gharali et al. | Reduced frequency effects on combined oscillations, angle of attack and free stream oscillations, for a wind turbine blade element | |
| CN101885381A (en) | Wing with recesses | |
| Bleischwitz et al. | Near-wake characteristics of rigid and membrane wings in ground effect | |
| Morton et al. | Rotor inflow noise caused by a boundary layer: inflow measurements and noise predictions | |
| Svorcan et al. | Current state and future trends in boundary layer control on lifting surfaces | |
| JP2017125603A (en) | Panel having non-uniform edge for reducing boundary layer peeling | |
| Hanson et al. | Experimental investigation of propeller noise in ground effect | |
| Bao et al. | The function of the alula with different geometric parameters on the flapping wing | |
| TW201538392A (en) | High pitch stall resisting propeller | |
| CN104097770B (en) | A kind of Helicopter Main rotor fin | |
| Syawitri et al. | A review on the use of passive flow control devices as performance enhancement of lift‐type vertical axis wind turbines | |
| Stürmer et al. | Installation impact on pusher CROR engine low speed performance and noise emission characteristics |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20180320 Termination date: 20210130 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |