GENER AL AVIATION
34 JANUARY/FEBRUARY 2017 AIRCRAFT MAINTENANCE TECHNOLOGY
ity and size, as well as NDT and alloy
requirements.
Cost is split between nonrecurrent
reverse engineering and mold design costs,
and part production cost. Lead time can
vary from several weeks for simple parts to
three to six months when complex reverse
engineering is required. The process is
much faster than the standard foundry
part development time.
AM of the above described part is some-
what simpler, since no molds are neces-
sary. At a current cost of $500 per cubic
inch of a structure, a motor housing would
cost about $50,000 per piece - way more
than this method.
So far, the absence of spare parts meant
in past a sure "death" of an aircraft. With
this reverse engineering, the operational
life of an historical aircraft can be extend-
ed at a manageable cost. Smaller batches
are also affordable. The above engine
crankcase is only one example, a remanu-
factured brake drum of the Junkers JU52,
which was no longer available, was also
built. There are just few similar projects
in the USA and Europe that will lead to
whole aircraft in the next two to three
years with the use of reverse engineering.
For example, Replic Air from Toulouse,
France is building the Le Dewoitine D551,
an aircraft destroyed before its maiden
flight in WW2 (www.replicair.fr). In such
large-scale projects, the fuselages and
wings are "relatively" easy to manufacture
because they are made of wood or sheet
metal. However, problems arise with non-
existing undercarriage and engine compo-
nents. Here reverse engineering can make
a project feasible.
Currently the maximum possible size of
a part depends on the dimension of a job
box what still limits the production of some
parts. Software and testing techniques must
also be further developed and adapted. So
far, there are only a handful of companies
in the world that use this method. With the
fast growth of 3-D printing technologies
and machines, this will hopefully change
soon. For more information visit www.vin-
tair.com or www.ventana-group.eu.
MARINO BORIC graduated
with a university degree as
an aeronautic engineer, and
acquired degrees in business
development/trade and
commerce and in journalism. He
is a civil and military pilot and
has built experimental aircraft. As a journalist, he
specializes in aviation and propulsion and travels
worldwide, flight-testing UL, LSA, Experimental,
and certified aircraft. He is writing for U.S.,
European, and Chinese media companies.
THE JUNKERS JU52 original brake drum (left), and the new one using reverse
engineering (right).
AviationPros.com/company/10018066