controls, the flight control computers and the
actuators for rotor-blade control.
DLR says the advantages of FBL
over FBW include the high transmission
bandwidth, high reliability and low weight.
The FBL flight control system consists of
a quadruple redundant computer and is
designed such that the stringent safety
criteria of the European aviation authorities
are met in full.
“We’re also investigating new control
schemes [with the EC135], for helicopters,
flying with active sidesticks, feet on the floor
etc,” revealed Brieger.
Another concept DLR is researching
involves combat search and rescue missions
as Brieger explained: “The task is to recover
someone who may have ejected or who is
in hostile territory in any kind of weather
conditions. The aircraft is fitted with a sensor
pack consisting of a radar, stereo FLIRs and
a laser scanner. The idea is the helicopter
overflies the projected landing area, the
sensor package then makes a sweep of that
and the aircraft then performs the approach
and landing automatically.”
The helicopter’s 3D database is
enhanced in real-time with information
coming from the sensor suite to provide a
“consolidated picture”, which is depicted for
the pilot via a helmet-mounted display to
ensure situational awareness is maintained
throughout.
The Bölkow Bo105 is used as a universal
science platform. Among the missions it has
conducted are studying flight characteristics,
low-noise approaches, thermal-imaging
photography, pilot-assist systems and flying
with external loads. Sometimes a nose
boom is fitted to the helicopter for research
into inflow conditions, and with pressure
sensors and strain gauges fitted on the main
and tail rotor blades for measuring the forces
and pressure conditions on the rotor blade.
Other modifications to the helicopter include
external hardpoints and an IFR-compliant
cockpit.
“On the smaller side, we also operate high-
tech gliders, which are fitted with a bunch ofsensors and data acquisition systems for air
elasticity research etc,” explained Brieger. “We
also have a General Aviation aircraft which we
use as a tow ’plane”.
DLR retired its ATTAS (Advanced
Technologies Testing Aircraft System),
D-ADAM (c/n G17) in 2012. The aircraft,
based on the VFW 614, was the fixed-wing
equivalent of the EC135, used as a flying
simulator, to replicate the flying behaviour
of other – existing or virtual – aircraft. A
programme is now under way to define a
successor aircraft for the ATTAS platform.ASSIGNMENT
Usually the scientific institutes carrying
out the research have a good idea as to
the platform they require for their research.
Studies using optical systems are often
conducted with the Dornier 228s because
they are unpressurised (they are also flown
above 12,000ft, but with those on board on
oxygen).
“It is important for the optical systems that
there is no additional window in between sothey can actually place their equipment into
the atmosphere directly,” said Brieger.
Sometimes the researchers wish to use a
combination of aircraft for their project.
Part of DLR’s mission is to make their
aircraft available to a national or European
institution or industry, which involves working
with external customers. In this instance, the
research team defines the mission and DLR
informs them which is the most appropriate
test bed.
The lead time for missions is lengthy due
to the complex nature of some of them and
the aircraft modifications required.
“On HALO, those missions are
so complex, we can have up to 100
modifications for one mission,” revealed
Brieger. “We [can] put 15 different racks with
scientific instruments in the cabin, maybe
additional external instruments. Usually for
the G550, project planning will commence
three years in advance of the mission.”
Some projects require specialist
equipment to be developed, which has to
be certified to varying degrees. DLRWorkstations are set up in the back of DLR’s Cessna Caravans enabling them
to be used as flying classrooms. AirTeamImages.com/Wolfgang MendorfThe Bölkow Bo105 is used as a universal science platform. Among the missions it has
conducted are studying flight characteristics, low-noise approaches and thermal-imaging
photography. AirTeamImages.com/Felix Gottwaldhttp://www.aviation-news.co.uk 3936-40_dlrDC.mfDC.indd 39 05/01/2018 16:54