The utility model coaxial helicopter rotor system relates to aeronautical engineering, in particular, to the design of a helicopter with coaxial rotors and a control system for these rotors, which allows the installation of upanddown equipment that can be pulled upward so that it can rotate around the rotor axis of rotation. The goal of this project was to discover the various design problems encountered when designing a coaxial rotor and it helped me realize how awesomely well. Design and testing of a quad shrouded rotor micro air vehicle. See, the tail rotor is a mechanism that makes up for the tendency of turning. Coax helicopters coaxial rotor helicopters and large drones. Avxs design see image combines coaxial rotors with ducted fans and small wings. A vectoring thrust coaxial rotor for micro air vehicle oatao. Design and testing of a quad shrouded rotor micro air vehicle in hover vikram hrishikeshavan1 and james black2 and inderjit chopra3 alfred gessow rotorcraft center, department of aerospace engineering, university of maryland, college park, 20742 rotor hover performance can be enhanced by enclosing it in a shroud.
Study of contrarotating coaxial rotors in hover, a. A survey of theoretical and experimental coaxial rotor aerodynamic research colin p. Rotor hover performance and system design of an efficient. A rotor system in which two rotors are mounted on the helicopter rotating in the opposite direction but running on concentric shafts. In this paper, we will first introduce the coaxial design concept by illustrating several coaxial helicopters. Hover performance correlation for fullscale and modelscale coaxial rotors. Thrust is provided by two ducted fans that are mounted at the rear of the aircraft and spaced apart laterally. A significant advantage of coaxial main rotor systems is the elimination of the need for a tail rotor for antitorque control. Simulating the unsteady aerodynamic loads for a coaxial rotor, including the aerodynamic interactions between rotors and rotor.
May 27, 2015 ive seen lots on the web about why a balun is essential to a coaxial fed antenna, and it holds true in my experience. Even eads north america has put in a bid, likely based on eurocopters x3 hybrid helicopter. The first set of these tests was performed with manual. In this thesis the design of a coaxial micro helicopter is presented and based on the design, a model is fabricated. Since reactive moments of coaxial rotors are canceled by contrarotation, no tail rotor is required to counter the torque generated by the main rotor. Design, fabrication and hovering performance study of nano coaxial rotor article pdf available january 2011 with 85 reads how we measure reads. Hover performance correlation for fullscale and modelscale coaxial rotors 2009 fig. Oct 28, 2008 october 28, 2008 helicopters featuring coaxial rotor designs are not exactly new. Tangler national renewable energy laboratory 1617 cole boulevard golden, co 80401 introduction the objective of this paper is to provide a historical perspective of the evolution of rotor and blade design during the last 20 years. Studies on coaxial rotor performance are highlighted below. Size restrictions force mavs to operate in a low reynolds number aerodynamic regime that results in poor aerodynamic performance of conventional airfoils and rotor configurations. The geometric properties of the two types of rotors are contrasted in table 1.
Unsteady loads for coaxial rotors in forward flight. Multiblock grids and multiple frame of reference mfr method. Rotational maneuvering, yaw control, is accomplished by increasing the collective pitch of. Rotational motion in designs that exclude the tail rotors is achieved by using two sets of rotor blades rotating in opposite directions, canceling each others angular.
Pdf computational study of flow interactions in coaxial. Experimental comparison of planar and coaxial rotor con. Design, analysis and hover performance of a rotary wing micro. Optimal aerodynamic design of conventional and coaxial. Ive seen lots on the web about why a balun is essential to a coaxial fed antenna, and it holds true in my experience. October 28, 2008 helicopters featuring coaxial rotor designs are not exactly new. Performance analysis of a coaxial rotor system in hover. Kamov ka50 black shark the advantages of coaxial rotors are that you rem. The coaxialrotor uav is composed of offtheshelf electronic parts and plywood foamboard laser cut parts. The unsteady aerodynamic loads on the x2 coaxial rotor are simulated in forward flight, and compared with the results of prasadum parallelized rotorcraft analysis for simulation and design, developed at the university of maryland and cfdcsd computations with the overflow and the createav helios tools. Pdf design, fabrication and hovering performance study of.
Its design approach is aimed at swapping the main rotor with rigid coaxial blades, shortening the tail, removing the tail rotor, and adding twin ducted fans for higher performance, and longer range. Pdf numerical simulations have been conducted for a coaxial rotor tested by harrington. Design and testing of a quad shrouded rotor micro air. Design, analysis and hover performance of a rotary wing. Computational study of flow interactions in coaxial rotors. The coaxial design of a pair of rotors mounted on the same mast and with the same axis of. These factors are critical in the design of compact and safe heavylift muavs for the application of parcel delivery in urban areas 2 and make coaxial rotors a popular choice for pavs. Recent advances in coaxial rotor design have shown bene.
Impact of rotor design on coaxial rotor performance, wake. Radical dual tilting blade helicopter design targets speeds. A study of coaxial rotor performance and flow field. The compact design of a coaxial propulsion systems enables the uav to have a higher thrusttovolume ratio and provides redundancies for motor failure 3. Coaxial helicopters also have the added benefits of. Also, comparison to singlerotor helicopter will be made to show the advantages of coaxial design. Other, like sikorsky, have shown their interest in this technology through the abs helicopter of the 1960s or today the x2 demonstrator, figure 3.
The most obvious examples come from kamov, for transport, antisubmarinesurface unit warfare and attack helicopters. Pdf this work presents a novel design methodology for multirotor unmanned aerial vehicles uavs. Based on this design, a simple dynamic model was developed with unique. Finally, simulation results show the effectiveness of the proposed controller design in the step response of the closed loop. The aim of this paper is to quantify, through numerical simulation. It has been used as a testing platform for control system and algorithms. Without a tail rotor, how does a coaxial rotor helicopter achieve yaw control. Design and performance of a ducted coaxial rotor in hover and. The momentum theory suggests that the minimum induced losses for coaxial rotors is attained when the lower rotor operates in the fully developed slipstream of the upper rotor and at equal and opposite torque. Minimum power requirements and optimal rotor design for. A dual, coaxial rotor helicopter is provided that is relatively easy to fly. Furthermore, the h loopshaping control was proposed to apply the control design of the coaxial rotor helicopter to manage complicated uncertainties and multivariable coupling.
Hover performance correlation for fullscale and modelscale. This dissertation investigates the optimal aerodynamic performance and design of conventional and coaxial helicopters in hover and forward flight using conventional and higher harmonic blade pitch control. First, we describe a method for determining the blade geometry, azimuthal blade pitch inputs, optimal shaft angle rotor angle of attack, and division of propulsive and lifting. This rotor configuration is a feature of helicopters produced by the russian kamov helicopter design bureau. The coaxial design is favored by most of the key design criteria. The coaxial design of a pair of rotors mounted on the same mast and with the same axis of rotation, but turning. Extensive research and development is currently underway to design next generation coaxial main rotor systems for heavy lift, high speed and smallscale. The goal of the project was to design and fabricate a testing rig able to quantify thrust and torque of electrical uas coaxial configurations. Pdf optimal aerodynamic design of conventional and. Design and performance of a ducted coaxial rotor in hover.
The coax unmanned aerial vehicles uavs format, will be large load carrying drones which can be converted easily from cargo to passenger format. This document presents the main steps to build a flyable coaxial rotor uav. As it is based on the blade element theory, it could be used as a design tool where the engineer can modify all parameters. The coaxial rotors are preferably utilized primarily for.
Analysis of coaxial rotor systems has progressed over the last decade thanks to improved modeling capabilities. Why coaxial helicopter rotor blades are so uncommon. In the past when i have made baluns i just twist some coax around a pvc pipe 8 or 9 times and call it good, but i would like to get a little more scientific. Disadvantages include increased mechanical complexity and increased parasite drag which can impede high speed performance. Differential thrust generated by the fans provides yaw control for the aircraft, and forward thrust is provided by the fans working in combination. Pdf this paper proposes a novel dissimilar coaxial rotor concept with. Finally, we combine our forward ight optimization procedure and the blade element momentum theory hover optimization to form a variational approach to the multipoint aerodynamic design optimization of conventional and coaxial helicopter rotors. Vagis kamov company, moscow region, russia september 1416, 1999 rome italy. This con guration is also more suitable for operating with strong winds 1. In this report, we present a novel coaxial design in which both upper and lower rotors are contained within a ducted fan, the speeds of both rotors are independently controlled, and the lower rotors cyclic pitch is controlled through a swashplate. Only the kamov design bureau of russia was successful in production of coaxial rotorcraft in 1970s. It was found that the coaxial rotor spacing effect on hover performance was minimal for the rotor spacing larger than 20% of the rotor diameter.
To address this limitation, this work will consider the use of coaxial rotors in the design. Because the rotors are not intended to be used for forward thrust, the power requirement for the rotors is lessened compared to a conventional design. Study of contrarotating coaxial rotors in hover, a performance. Nevertheless, issues related to rotorhead drag, aerodynamic performance, wake interference, and vibration should also be considered. Coleman 1 provides a summary of experimental and analytical studies of coaxial rotors through 1997. A fully functional coaxial mav was developed based on the aerodynamic studies performed. In the 50s gyrodyne usa developed the xron, figure 3, a one seat coaxial helicopter. Ercoftac international symposium unsteady separation in fluidstructure. Coax helicopters leverages solidworks premium design and solidworks composer technical communication software to commercialize coaxial rotor helicopter technologypreviously used only by the militaryfor use in manned and unmanned applications. Alternatively to the solution with the rotors in the same plane planar con guration, the coaxial con guration arises, with the rotors positioned in pairs, allowing for a more compact design. Coax helicopters will be available in a single seat version with 17 foot or 20 foot rotor system. They are offering a compound helicopter based on sikorskys x2 highspeed coaxialrotor configuration. Design and testing of a quad shrouded rotor micro air vehicle in hover vikram hrishikeshavan1 and james black2 and. Modeling and control of coaxial uav with swashplate.
The link goes to wikipedias article, and down a ways it says. Unsteady loads for coaxial rotors in forward flight computed. Pdf design, fabrication and hovering performance study. The design of an efficient coaxial rotor system requires an accurate assessment of aerodynamic interferences between the rotors. Jan 21, 2017 there are som, but not very many at all. Aerodynamics optimization of a ducted coaxial rotor in. The coaxial rotor uav is composed of offtheshelf electronic parts and plywood foamboard laser cut parts. Aug 23, 2011 the goal of this project was to discover the various design problems encountered when designing a coaxial rotor and it helped me realize how awesomely well made kamov rotors are. Kamov design bureau have made the choice of coaxial systems which led to the ka32 or ka50 figure 3, for example. Pdf design methodology for heavylift unmanned aerial. Ill go the other direction and talk about the advantages and disadvantages of tail rotors, which are the disadvantages and advantages of coaxial rotors, respectively. Hover performance correlation for fullscale and model.
Unlike the single main rotor design that distributes power to both main and tail rotors, all of the. To investigate the aerodynamic complexities involved in the combination of freestream and propellers suction flow field of ducted coaxial rotors system in forward flight, an orthogonal test design has been applied to optimize the design parameters including forward speed, pitch angle, and axial spacing between rotors. Coaxial rotors or coax rotors are a pair of helicopter rotors mounted one above the other on concentric shafts, with the same axis of rotation, but turning in opposite directions contrarotating. Radical dual tilting blade helicopter design targets. Details of such configuration were provided and initial testing related to descend flying conditions was discussed. Reviewing and investigating the use of coaxial rotor systems in. The influence of several design parameters rotor spacing, duct inlet shape, position of rotors within the duct, and tip clearance on performance was determined. Design for conventional, compound, and coaxial helicopters using higher harmonic control by eli b. Modelling the lama coaxial helicopter li chen school of computer science and software engineering. The thesis starts with the introduction on the previous models of micro.
Although the first idea of coaxial rotors appeared more than 150 years ago, most helicopters have used single mainrotortailrotor combination. The utility model coaxial helicopter rotor system relates to aeronautical engineering, in particular, to the design of a helicopter with coaxial rotors and a control system for these rotors, which allows the installation of upanddown equipment that can be pulled upward so that it. The present paper deals with the optimal design of a coaxial rotor system in hover and axial climb. Coleman ames research center summary the recent appearance of the kamov ka50 helicopter and the application of coaxial rotors to unmanned aerial vehicles have renewed international interest in the coaxial rotor configuration. This document presents the main steps to build a flyable coaxialrotor uav. What are the advantages and disadvantages of coaxial rotors. A coaxial rotor system is an arrangement that contains two identical, or nearly identical, counterrotating rotors along a common spin axis. Autonomous systems laboratory, department of product design and. A survey of theoretical and experimental coaxial rotor.