Project: Development of an innovative compact actuator for the stability control of ultralight aircrafts

There is a growing worldwide demand for both manned and unmanned ultralight aircrafts. The definition of ultralight (or microlight) aircrafts according to the Joint Aviation Authorities document JAR-1 is an aeroplane having no more than two seats, maximum stall speed of 65 km/h CAS, and a maximum take-off mass of no more than 300-595 kg depending on the number of seater._x000D_Applications include leasure and sport, but also environmental monitoring, security and scientific applications. In all these cases the stability of the platform is becoming a very stringent requirement as it affects the quality of the work performed by the aircraft. For manned vehicles safety is also a major issue as many accidents were due to failure of the stability control system._x000D__x000D_Suppliers are requested to provide safer and more reliable stability control systems to comply with the increasingly stringent performance requirements. In particular there is a request for more accurate positioning of the flaps, increased system reliability, and smaller weight and volume. These targets can be achieved using a totally innovative concept of actuator which substitutes the presently produced systems characterized by long transmission chains (including up to 10 gears). _x000D_The objective of the FLY-GEAR project is the development of a totally innovative actuator for stability control of ultralights making use of NUGEAR, a patented gearbox system based on the concept of nutation coupled with bevel gears._x000D__x000D_The small electric motors used as power sources in actuators for stability control systems have high rotational speeds and low torque ratings. Their typical speed is between 6 and 10.000 rpm, too fast to be applied to flaps. Therefore it is necessary to use a gear-reduction system that reduces the motor’s speed and multiplies its torque to the level required. State-of-the-art solutions applied to commercially available actuators include: several stages of planetary gear trains in series and conventional cylindrical couples. They have too many transmission couples to insure the requested precision and stiffness of the system. The harmonic drive is the most accurate gearbox available in the market but it is too expensive and the flexible element included in the system is not compatible with the requirements of robustness of the system. _x000D_The NUGEAR system (Patent N. 0001323689) couples the mathematical concept of nutation with bevel gears. The NUGEAR is characterised by: small size (only four bevel gears required), small weight, multiple teeth engagement (that guarantees higher safety and reliability), small backlash and high torsional stiffness._x000D__x000D_The limiting factor to the industrial exploitation of the NUGEAR lies in the difficulty of manufacturing the internal bevel gear, which is part of the system, with conventional CN machine. _x000D_At present, the NUGEAR has been successfully used for space applications, where the manufacturing problem was solved using the spark erosion technique. Such technique, however, is not suited for large series. The research work to be performed is therefore composed by two CO subjects:_x000D_1) the research of the best architecture that will see the NUGEAR integrated in the FLY-GEAR actuator, with the proper design and the appropriate electronics;_x000D_2) the research on the manufacturing process suited for internal bevel gears. _x000D__x000D_The market for ultralight aircrafts is a significant portion of the aeronautic market, with an amount close to the 20% of the whole civil air force. This market developed so much that ultralights production almost triplicated in the last four years. _x000D_Today the market of stability control systems is dominated by overseas manufactures, COly from the United States. In the European Union, Turkey, Portugal and the Netherlands together represent a powerful industrial district able to overcome the American competition due to their strong and complimentary technical capabilities. _x000D_The objective of FLY-GEAR can only be addressed at a European level rather that a national/regional/private level because of the geographical dispersion within EU of technological expertise and know-how needed to achieve the project objectives. The Consortium is composed by SMEs from the countries who will benefit most from the proposed project: Portugal, Turkey and the Netherlands. A well balanced Consortium has been established in order to provide a close technical cooperation among Ps with complementary experiences. The core SME group are well distributed from a geographical point of view (the Netherlands for Northern Europe; Portugal for the western Europe and Turkey for the Eastern Europe) and their business activities cover a wide range of applications relevant to the project.

Acronym FLY-GEAR (Reference Number: 4259)
Duration 01/07/2008 - 30/10/2010
Project Topic There is a growing demand for both manned and unmanned ultralight aircrafts. Suppliers are requested to provide safer and more reliable stability control systems. The aim of FLY-GEAR is the development of a totally innovative actuator for stability control of ultralights based on NUGEAR technology.
Project Results
(after finalisation)
Even though the goals were extremely challenging, the Consortium proved its high-tech skills and expertise, and led the project from a raw idea to the final prototype of the servo-mechanism and its testing._x000D_The project achievements are summarized as follows:_x000D_1) The optimized prototype of the actuator for stability control, in real scale._x000D_2) An innovative manufacturing process for internal bevel gears, to enable to produce the needed gears at a reasonable price._x000D_3) A NUGEAR prototype, that was tested independently._x000D_4) A validated numerical model of the NUGEAR system, to enable further applications of the technology._x000D_5) Test results, that will constitute the background for system qualification.
Network Eurostars
Call Eurostars Cut-Off 1

Project partner

Number Name Role Country
3 Active Space Technologies, Actividades Aeroespaciais Lda. Coordinator Portugal
3 Bierens Machinefabrieken B.V. Partner Netherlands
3 Global Teknik Elektronik Yazilim Mühendislik Hav. San. Tic. A.S. Partner Turkey