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Introduction

Today’s large transport aircraft all share a common tail design with aft body-mounted horizontal stabilizers and a vertical fin. After gradual development over decades, this concept has now reached a degree a maturity that leaves only limited room for further improvements. To explore the possibilities of unconventional tail designs on civil aircraft, the EU funded research programme ”New Empennage for Aircraft” (NEFA) was conducted, comprising structural-, flight mechanics and aerodynamic aspects.

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Project description

Within the NEFA project, multidisciplinary investigations on the feasibility of H-, U- and V-tail designs for a generic twin-jet transport aircraft were carried out. In terms of increased aerodynamic efficiency and reduced production costs, the V-tailed aircraft was found most promising. Such a configuration offers the advantage to provide lateral and longitudinal stability by only two stabilizer surfaces, instead of three. Possible aerodynamic benefits are reduced interference drag and a slightly smaller wetted tail surface area. Also the reduced number of tail surfaces leads reduced production costs compared to conventional designs.

ISM contributed detailed numerical investigations on the high lift and tail-stall characteristics of the NEFA V-tail- and reference configuration. The RANS-solver TAU was employed for a total of over 45 simulations on hybrid grids with high resolution. The results were found to be in good agreement with experimental data from DNW-LLF experiments, giving accurate predictions of tail-stall onset and characteristics.  Sideslip was identified to have a strong influence on the V-tail’s stall behavior. Due to lateral/longitudinal coupling, sideslip will increase the lift of the windward side of the V-tail, while it decreases it on the leeward side.  This may lead to a one-sided tail-stall at comparably low angles of longitudinal incidence. Furthermore aerodynamic shading must be taken into account as a possible cause of flow separation. An overview of some results can be found here.

The NEFA reference configuration served as the pioneer test case for the application of 3D-transition prediction methods to a full aircraft configuration. (see this link)

 

Contact: Dipl.-Ing. M. Kruse (m.kruse@tu-braunschweig.de)

 

To be published:

Kruse, M., Radespiel, R.: On the effective angle of attack for the evaluation and comparison of V-tail aerodynamic data.


  aktualisiert am 27.06.2008
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