IndustryAerospace

Business challengesRetain process edge throughout product developmentIncrease production efficiencyReduce the number of prototypes and physical testsSecure the company’s competitive advantage

Keys to successEstablish a global service networkContinue to introduce new product developments and enhancementsLeverage finite element analysis for materials testing

ResultsReduced number of tests and prototypesCompressed production timesPushed back material boundariesImproved manufacturabilityIncreased sales/growth

MT-Propeller develops better products using Femap with NX Nastran, reducing prototype testing, improving manufactur-ability and increasing sales/growth

High-tech and innovation – made in Bavaria Ever since the advent of jet aircraft, the manufacturers of airplane propellers have dwindled in both numbers and relevance. But today, prop airliners are regaining importance, especially over short dis-tances, such as European regional routes. They are faster, use less fuel, release less harmful emissions and are now just as quiet and vibration-free as jet engines. As one of only three remaining worldwide propeller manufacturers, MT-Propeller Entwicklung GmbH plays a major role in this trend. From Straubing Airport

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MT-PropellerReaching performance limits safely

(Germany), it dominates the European market for aircraft propellers. Since its founding in 1981, the medium-sized engi-neering and manufacturing company has carved itself a dominant market share of 85 percent in the new aircraft segment. Its average growth rate in recent years has been about 20-25 percent. The company’s

Regional airliner Jetstream 32 of British Aerospace.

Regional airliner Dornier 228 NG (new generation).

through in-house manufacturing all the way to maintenance, all processes are optimized in an effort to realize perfection. The eight-member development team is able to master a multitude of variations thanks to a configurable, modular system of 28 basic patterns and about 300 differ-ent blade designs, to which new develop-ments are constantly added. MT-Propeller achieves lofty standards of quality and pre-cision with the use of modern computer-aided design (CAD)/computer-aided manufacturing (CAM) systems, as well as finite element technology. The goal is clear: the number of prototypes must be reduced. Every single prototype means a delay of about seven weeks in lead-time. That’s because before propeller blades can be marketed, they must undergo lengthy endurance and fatigue tests for the pur-pose of certification.

Pushing back the limits of materialsBeing able to accurately predict interacting material behavior is crucial when design-ing a propeller made of composite materi-als. For this, MT-Propeller has been relying on Femap™ software for finite element analysis (FEA) and the Nastran® software solver since 1998. “Femap and NX Nastran have played a major part in the company‘s growth,” says Martin Albrecht, CEO at MT-Propeller and reigning German cham-pion in aerobatics. “They are great tools in

expansion into the significantly larger and highly important U.S. market is in full swing.

The MT-Propeller Group, which includes MT-Propeller Entwicklung GmbH, MT-Propeller Gerd Mühlbauer GmbH, Avia Propeller and MT-Propeller USA Inc., employs about 150 people worldwide. Its competitive edge is the result of a high level of innovation, constant enhance-ments and a global sales and service network.

Competitive edge through excellence and efficiencyThe innovative MT natural composite pro-pellers have been increasingly successful in the company’s target markets. Aerobatic pilots from all around the world trust the high-tech products, as do well-known sup-pliers of do-it-yourself (DIY) aircraft. Similarly, large aircraft manufacturers rec-ognize the tremendous benefits of MT-Propeller‘s products. The special, pat-ented natural composite blades, consisting of a plasticized wood core, a shell of fiber-reinforced plastics, and a bonded metal erosion sheath, are lighter than aluminum blades and present excellent vibration damping characteristics. Nonetheless, they have the tensile strength of steel and are virtually impervious to material fatigue. This is the type of five-blade propeller that was developed by MT-Propeller for RUAG Aerospace to fit into its twin-engine Dornier 228 NG commuter aircraft. As a result, a weight reduction of about 35 kilo-grams was achieved, and the noise level inside and outside the passenger cabin was cut in half. Yet, the propeller-driven turboprop is now flying at a much higher rate of climb and top speed.

Run by engineers, the forward-looking company has put a lot of effort into achieving its competitive edge, which it plans to expand through further innova-tion. From the development stage,

“Femap and NX Nastran have played a major part in the company‘s growth. They are great tools in our business.”

Martin Albrecht CEO MT-Propeller

Innovative high-tech propellers in composite construction.

Structural analysis of a propeller hub.

into a finite element modeling (FEM) version and transfer them seamlessly into Femap. This is where all the materials and the complex boundary conditions are defined. The NX Nastran solver calculates the result in just 4 to 5 hours. The solution is available quickly as a result, with any inaccuracies in the boundary conditions detected in a timely fashion. High flexibil-ity and fast reactivity greatly reduce delays.

Identifying problems earlyThe Femap pre- and postprocessor clearly demonstrated its usefulness when the bonding of steel and the composite mate-rials on a newly launched propeller blade model came undone. While the cause was first investigated as a possible manufactur-ing fault, the verification using Femap with NX Nastran showed that the adhesive could not withstand the high shear stresses – a serious problem, as the series production of the blade in question was already underway. Thanks to Femap, it was possible to figure out another com-posite fiber layup, which provided the solution. “Based on finite element analysis, we were able to reduce stress by a third,“ recalls Martin Albrecht. The result was immediately transferred to the manufac-turing process. Five weeks later, the real stress testing confirmed that the solution identified with Femap was safe and entirely implementable.

Using Femap with NX Nastran, today MT-Propeller only produces one single pro-totype for each propeller blade, which can usually go into production without further changes. It was therefore possible to sig-nificantly reduce the already very good average of one to three prototypes. As a result, MT-Propeller achieved considerable time savings in the development stage. The company is now 99 percent sure that the computer-generated model will be fea-sible. The new development of a propeller system for the BAE Systems Jetstream 41 is

our business. With these tools, we are able to push material boundaries even further and what we build is thus much lighter, but just as safe.”

Femap, a CAD and solver-independent pre- and postprocessor, helps MT-Propeller identify and eliminate weaknesses at an early stage, which is a determining factor in raising product quality significantly. MT-Propeller implements the user-friendly solution on any standard Windows® oper-ating system to perform static, dynamic, linear and nonlinear calculations. The stress behavior in the propeller blade can be analyzed in this way for every situation. Here, Femap is able to simulate all of the many different materials, as well as the different transitions. “Femap is a great tool in the company,” notes Albrecht. “Whoever programmed the system has to be a genius.”

The computer calculations often confirm the long-standing expertise and acquired insights of the MT-Propeller engineers – with the great advantage that those already accurate estimates are precisely validated with the help of Femap and now NX™ Nastran software as well. MT-Propeller operates its simulation and validation process with an error probability of less than one percent. For simulation, the designers convert the 3D CAD models

“ Intensive guidance, individu-alized training and ongoing support – our customers deserve the best, of course.”

Rolf Bröske CEO SMART Engineering GmbH

With finite element analyses, MT-Propeller increases product quality.

Martin Albrecht‘s Extra 330SC was the winning aircraft at the German championship in aerobatics, 2010.

SMART Engineering GmbH, a specialist in FEM calculations and distributor of Siemens PLM Software solutions. Through individually tailored training and ongoing support, SMART Engineering helped ensure the smooth integration of software tools throughout MT-Propeller‘s everyday development routine. “Rolf Bröske and his SMART Engineering company really know a thing or two about software,” says Albrecht. “The care and support we receive are just great.”

© 2012 Siemens Product Lifecycle Management Software Inc. All rights reserved. Siemens and the Siemens logo are registered trademarks of Siemens AG. D-Cubed, Femap, Geolus, GO PLM, I-deas, Insight, JT, NX, Parasolid, Solid Edge, Teamcenter, Tecnomatix and Velocity Series are trademarks or registered trademarks of Siemens Product Lifecycle Management Software Inc. or its subsidiaries in the United States and in other countries. Nastran is a registered trademark of the National Aeronautics and Space Administration. Windows is a registered trademark of Microsoft Corporation. All other logos, trademarks, registered trademarks or service marks used herein are the property of their respective holders.Z7 23790 3/12 Cwww.siemens.com/plm

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Americas +1 800 807 2200 Europe +44 (0) 1202 243455 Asia-Pacific +852 2230 3308

Solutions/ServicesFemap www.siemens.com/plm/femapNX Nastran www.siemens.com/plm/ nxnastran

Customer’s primary businessMT-Propeller designs and manufactures innovative aircraft propellers for the global market. www.mt-propeller.com

Customer locationAtting Germany

PartnerSMART Engineering GmbH www.smart-fem.de

current proof of the performance displayed by MT-Propeller. In just six months, propel-lers were produced for the 32-seat twin engine turboprop aircraft, which operates at 600 kilometers per hour at top speed. The aircraft generates 3.2 tons of thrust during take-off at 1,680 horsepower – without faults and within the preset deadline.

Assuring smooth integration through excellent trainingMT-Propeller received an excellent intro-duction to Femap with NX Nastran from

“ Based on our finite element analysis (technology), we were able to reduce stress by a third.”

Martin Albrecht CEO MT-Propeller