Aeronautics Research 2002 - 2006 projects

82
Strengthening Competitiveness
NEFS
New track-integrated Electrical
single Flap drive System
Background
The high lift system of large transport
aircraft comprises leading edge slats and
trailing edge fl aps and is deployed during
take-off and fi nal approach, providing
additional lift to get or stay airborne at low
speeds.
Symmetric fl ap actuation is traditionally
assured by coupling all fl ap surface
actuators to a torque shaft system, which
extends along the rear spar of both wings
and is driven by a centralised hydraulic,
electric or hybrid motor. The actuators
are located at or near special fl ap support
structures called track beams which
transmit the lift produced by the movable
fl ap surfaces to the wing.
Conventional fl ap drive systems have a
low effi ciency, require a high installation
effort with shafts and gearboxes distributed
across most of the wing trailing
edges and offer no functional fl exibility,
e.g. differential surface defl ection.
It is the target of NEFS to fundamentally
change the high lift drive system and
structure presently installed in commercial
transport aircraft. It is proposed to
develop a distributed electrical fl ap drive
system that is completely integrated with
the fl ap track beams. This new technology
is an enabler for new functionalities,
which are developed in related RTD projects
like AWIATOR, NACRE or ATEFA. It
will also allow an increase in the fault tolerance
of the high lift system.
system and centralised motor will be
replaced. The track beams will be redesigned
to enable an optimised systemstructure
solution for this new fl ap drive
system. This provides the opportunity for
an innovative composite design in fl ap
support structures.
The proposed fl ap drive system offers
a fundamental change in high lift drive
technology compared to state-of-the-art
systems. The expected benefi ts are:
– new functionalities of the high lift system
via differential fl ap setting (DFS),
like accelerated vortex decay, roll trim
and roll control support
– reducing operational interruptions
caused by high lift systems by at least
15%
– improving the drive system effi ciency
by at least 25%
– a 2-3% L/D improvement in cruise
– a 20% weight reduction of the fl ap
track beam due to highly integrated
composite design
– a 5% cost reduction in the manufacturing
and assembly of the fl ap track beam
due to the minimised number of parts
– improved maintainability
– reduced installation effort (for design
and manufacturing).
Description of work
As a baseline for the boundary conditions
and the assessment of improvements,
reference data will be adopted from a
state-of-the-art commercial transport
aircraft.
Objectives
One of the main criteria for the system to
The main objective of NEFS is to replace be developed is the high requested level
the traditional drive systems by a distrib- of redundancy, primarily concerning the
uted electrical fl ap drive system that is motors and electronics. To address this
completely integrated into the fl ap sup- problem, advanced redundancy concepts
port structure. The transmission shaft will be developed.