spray and another to spray the thermobaric coating. The
robot can be used to coat cracks inside a jet engine, for
example in the combustion chamber, preventing bigger
problems and costlier maintenance in the future.
One arm is first deployed to detect any damage, the
second is deployed by the operator only if damage is
found. All control is conducted locally. The temperature
while the coating is being deployed can rise to as much
as 3000˚C. “The coating has to be sprayed at the right
distance,” says researcher on the project Abdelkhalick
Mohammad. “It’s a difficult process and this is the first
time such a coating has been deployed inside an engine.
Performing this repair while the engine is on the wing
saves a tremendous amount of time – an entire day of
work potentially down to a couple of hours.”
FLARE was recently successfully demonstrated on
the combustor of a Trent 900 and deployed on a Trent
inspection & monitoring
80 SEPTEMBER 2019 \\ AEROSPACETESTINGINTERNATIONAL.COM
1000 engine, using 3D imaging to develop control and
navigation for the snake-arm. The robot is close to use in
the field, with a company ready to commercialize the
technology and in talks with the UTC.
IN-SITU INSPECTION
Another project is producing an integral boroscope that
can be retrofitted to engines to automatically detect and
repair damage to turbine blades, so that the lifetime of
the blades is significantly elongated.
The number of routine gas turbine inspections
having to be performed is increasing as aviation-use
grows. These inspections are time intensive, can vary
between inspectors, and offer limited data capture and
assessment possibilities. The Inspect project is
“We are attempting to develop an
endoscope which uses glass lenses and
able to survive a flight environment”
tip, which can be positioned to direct the
laser. The tool could also deliver air or
water via a jet. The cable would fed
through an engine to carry out
inspections and repairs.
The 5m cable complicates the control
of the arm and any effector considerably.
Alatorre says, “The cable is stretchy and
you need to understand how it moves and
how that affects the arm. The longer the
cable is, the more friction is created,
while bends and kinks affect the level of
force that is required to move the arm.
The aim is to develop a closed loop
feedback mechanism, so an operator can
easily use it.”
IN-SITU REPAIRS
Another recent project that has deployed
a larger snake-arm for aerospace engine
inspection and repairs is FLARE (Flame
Spray Adder for in-situ Patch Repair of
Aero-Engine combustors). This £1.5
million (US$1.8 million) Innovate
UK-funded project uses two snake-arms,
one to collect visual data about a defect
and to act as the igniter for the coating
developing an inspection system that mounts
permanently onto an engine’s port and automatically
extends downwards to examine compressor blades for
damage after every flight an aircraft makes.
Researcher on the project, Andres Gameros-Madrigal,
says, “At the moment we have a minimal number of
inspections to gather data. If we looked at every stop, we
can gather better information to analyze damage,
improve designs and maintenance schedules.”
Of the several challenges to overcome so that regular
automatic deployment of the system can be achieved, the
temperatures of up to 500˚C which are found within jet
engines that the device has to operate in, is perhaps the
most difficult.
The first version of the system uses fiber optic
strands to create a flexible probe. The thickness of the
walls has to be minimal to accommodate as many optical
£1.5 million
(US$1.8 million)
Cost of project
developing the FLARE
snake-arm robot
3 // Snake arm robots offer
the opportunity to inspect
parts of engines while they
are on the aircraft’s wing
(Photo: Alex Wilkinson
Media)
4 // Technology from
projects such as the
hexapod is used across
different prototype devices
4
3
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