Thursday 7th May 2015 ExpErt IntErvIEw · 2016. 8. 26. · 4 Institute for Engineering Design...

ExpErt IntErvIEw

General Information and Program

Thursday 7th May 2015

2 Institute for Engineering Design

Expert Interview 2015

prEfacE

Over the decades Rotorcrafts have been es-tablished for vertical lift operations. Be-sides the classical helicopters, tiltrotor- and

tiltwing aircraft have also been developed and en-tered service for special operations.However in recent years, driven by new operation-al challenges, especially high speed helicopter concepts have been evolved and novel concepts for vertical lift aircraft were presented by all ma-jor manufacturers. The requirements for future rotorcraft were discussed on many occasions and scientific congresses. Besides new mission pro-files and operational demands, the development

is influenced by new regulations from the Authorities.New concepts for vertical lift will require new solutions for propulsion. Apart from the totally new technological approaches for engines and elec-trical aircraft, all drive train components will have to be adapted for new rotorcraft concepts. Since 2008 TU Vienna is doing active research in the field of drive train technology for aircraft and would like to focus with new projects on these challenges, together with multinational companies and research institutes.In addition to the Vertical Lift Initiative activities of TU Vienna in IFAR, this international expert day would like to discuss new drive train concepts and challenges for future rotorcraft. Discussion and evaluation of new drive train concepts is envisaged to outline new technological solutions in accordance with certification specifications and to build up international cooperation early enough to reach a suitable TRL level and to be able to support the concepts of rotorcraft OEM´s.

Michael WeigandDean of Machine Design Department

3Institute for Engineering Design

2015 Expert Interview

OrganIsatIOn

I hope this program folder will provide an over-view on the scheduled events and firmly be-lieve it will arouse your interest.

The event is planned to be a platform for ex-changing ideas & information and to construct decision on the topics related with rotorcraft de-sign. The main topics covered in this session would be, initially about, the possibility to integrate the rotorcraft into a global transportation sys-tem. Secondly then, on the possible increase of efficiency and flight envelope of rotorcrafts by using transmission variable drive trains to vary

the rotor speed.To make the event livelier, we have conveyed for a friendly get together in the evening in a typically Viennese restaurant. We kindly request your es-teemed presence and participation to the a fore mentioned event.

Kindly find my contact details below. If you are interested to join to the Expert Interview 2015 please inform me! And also for any further queries please don’t hesitate to contact me. Thank you!

Hanns AmriGetreidemakt 9 / E307-31060 ViennaAustriaTel.: +43 1 58801 30611E- Mail: [email protected]

Looking forward to welcome you to the Expert Interview on Thursday 7th

May 2015!

Hanns Amri



Ifar- vErtIcal lIft

IFAR, the International Forum for Aviation Research, is the world´s only aviation research establishment network. IFAR is established on a vol-untary, non- binding basis.

IFAR aims to connect research organisations worldwide, to enable the information exchange and communication on aviation research activities and to develop among its members a shared understanding on challeng-es faced by the global aviation research community.

IFAR develops views and recommendations, e.g. the IFAR Framework Doc-ument on future research strategies and facilitates opportunities for net-working and partnerships.

IFAR develops a regularly updated IFAR Framework Document outlining global research objectives and technological opportunities for use by its Members. The focus of IFAR is on non-competitive aviation research and development related to global technical challenges and steps to reduce the impact of aviation on climate and the environment.

Beyond the scientific and technical activities IFAR aims also on exchange on education and promotion of youth scientists and engineers by the de-velopment of an action plan and specific measures.

IFAR Vision and Mission



IFAR Vertical Lift

IFAR discusses global air transport with the goal of minimal travelling times. Vertical Lift (VTOL) aircraft can be one important part of a global air transportation system reaching this goal.

Currently OEM’s of VTOL aircraft are working on new products based on individual motivation and scenarios and completely new concepts come up. The basic question is: “Are Rotorcraft a part of future global transporta-tion system?!”

The topic is about the requirements for new rotorcrafts and to get an idea how a new rotorcraft concept should look like. The focus is on speed re-quirements, efficiency and noise. Also already existing concepts should be presented and discussed.

📍 What has a new rotorcraft to fulfil to be part of a global transportation system?

📍 What are the requirements for air rescue, sea rescue, police and other typical mission profiles?

📍 Rotorcraft in offshore industry like oil production and wind turbines - are there special requirements?

📍 Rotorcraft in cargo transport: Are there special requirements for cargo transport?

📍 Is the rotorcraft an alternative for public transport and if, what is expected from the rotorcraft?

📍 New rotorcrafts as a private transportation system for the mass or only for a few people (business)?

📍 What are the requirements according to safety, reliability and maintenance?

📍 How fast should a rotorcraft be in the future?



varIablE rOtOr spEEd

Rotorcraft

Helicopters, as they are state of the art, produce lift and propulsion with the main rotor. Main rotor and tail rotor are driven by a turbine with constant speed and the power transmission is done by a con-

stant transmission gear box.

To use constant speeds simplifies the construction of blades and the whole rotor system. The reason is, that there is only one design speed for calculation and design. The eigen frequencies of the rotor are adjusted to the rotor harmonics that they are not in the same region. Therefore there is only a drive through without loads by starting or shutting down the engine. The best lift-to-drag-ratio of the blades is used at the design operational state.

Most of the time a rotorcraft works not in its design operational state. Therefore the rotorcraft cannot use the most efficient angle of attack of the rotor blades. To enable the rotorcraft to operate in the efficient point over a wide range of the flight envelope could increase the efficiency of the rotorcraft. This may lead to a reduced power demand and so to less fuel consumption. This might be also interesting in an ecological point of view for future rotorcrafts.

📍 Does the optimization of the rotor speed according to flight conditions result in an improvement for rotorcrafts?

📍 How much does the optimization of rotor speed increase the rotorcraft efficiency?

📍 Is there a difference for different rotor or rotorcraft config-urations? (For which types is it useful and for which not?)

📍 What about safety? Are there new risks or demands? 📍 Is an encrease of safety conceivable? 📍 Is there a need for new certification rules?



If we consider a speed variable rotor, there are two basic facts we have to think about. Firstly, “how can we vary the rotor speed?” To answer this question one needs to have deeper understanding by the drivetrain of a

rotorcraft.

For example if you consider a gear shift during flight, it is imaginable a difficult task, compared with the gear shift mechanism of an automotive. It must be ensured, that the power transfer is not interrupted during shift and the change of the rotor speed should not be abrupt. The turbine is working nearby with constant speed, so the adaptation of the rotor speed must be done by the gearbox.

Second, “What would be the dynamic behaviour of the rotor, when the speed is varied?” This question needs a deeper understanding of the rotor itself.

The dynamical behaviour of a rotor characterizes the vibratory loads of the whole helicopter. Rotor blades are, as a rule, designed so that its flap, lag, and torsional Eigen frequencies do not match with the rotor harmonics at nominal rotor speed.

📍 Are there different possibilities to change rotor speed? 📍 What are the advantages and disadvantages of a transmis-

sion variable gearbox? 📍 What are the basic requirements for such a gearbox? 📍 What are the main difficulties on the rotor to vary its speed? 📍 Is there a possibility to adapt the rotor to different condi-

tions? 📍 What are the main risks by changing the rotor speed during

flight? 📍 How should the new control variable be implemented?

(Workload for the pilot)

Drivetrain and Rotor



dEtaIlEd prOgram

Morning session: Vertical Lift

09:30 IFAR Program PresentationVertical Lift- as a part of global transport systemSpeaker: Prof. Michael Weigand, Technical University of Vienna

09:50 Trends in Future RotorcraftsRussian inventions and ideasSpeaker: Prof. Vladimir Zhuravlev, Moscow Aviation Institute

10:30 Coffee Break

11:00 High speed RotorcraftInventions on high speed rotorcrafts in RussiaSpeaker: Pavel Zhuravlev, Moscow Aviation Institute

11:30

Lunch Break

10:10 Trends in Future RotorcraftsEurope and US inventions and ideasSpeaker: Hanns Amri, Technical University of Vienna

DiscussionRequirements for future rotorcraft

12:30

Thursday 7th May 2015

Registration08:45

Welcome and Introduction09:15



Afternoon session: Variable rotor speed

14:30 Rotor behaviourDifficulties and benefits from variable rotor speedsSpeaker: Roland Feil, Technical University of Munich

14:50 Gear box designDesign process at the EC135 main gear boxSpeaker: Prof. Michael Weigand, Technical University of Vienna

16:20Discussion 3Are variable rotor speeds the future in rotorcrafts?

17:00 Closing remarks

15:40 Gear box designDesign process of a gear box in the industrySpeaker: Bernhard Wagner, Zoerkler

16:00 Transmission variable gear box Possibilities of transmission variable gear boxes in rotor-craftsSpeaker: Hanns Amri, Technical University of Vienna

19:00 Evening eventDinner in a typical Vienna location. We will start together from the university at Getreidemarkt.

Evening event



lOcatIOnThe Expert Interview takes place at Getreidemarkt 9 / E307-3. You will find it in the building “BD” the Stair 1 in the third floor.

Arrival by car:You can use the car park in Lehargasse!Arrival by plane:From the airport take the CAT or S7 train to “Wien Mitte”. Then Take the subway U4 to “Karlsplatz”.Arrival by train:If you are at Westbahnhof than take the subway U3 to “Neubaugasse”. Go to the “Haus des Meeres” and then follow the “Gumpendorferstraße” to city center. If you are at Hauptbahnhof take the subway U1 to “Karlsplatz”.



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Published by: TU Vienna, Karlsplatz 13, 1040 Vienna, AUSTRIA

General CONTACT:TU Wien - Institut für KonstruktionswissenschaftenGetreidemarkt 9/307, A-1060 Wien

[email protected] http://www.ikl.tuwien.ac.at Tel: +43 1 58801 30601

Thursday 7th May 2015 ExpErt IntErvIEw · 2016. 8. 26. · 4 Institute for Engineering Design...

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