| In
May 1996, the prototype UFM-13 was submitted to a rigorous
program of flight tests and load tests, which included testing
the wing to destruction (up to +12g's) at the Aeronautical
Engineering faculty of Brno University.
All of the composite components are built in high quality
molds, thus ensuring a much higher standard of accuracy
and finish then is obtainable with any other method of construction.
The materials used (imported glass and carbon fibre epoxy
laminate of aircraft manufacturing grade) guarantee uniform
qualities of strengh and lightness. The plane successfully
passed the wing loading test carried out at the Aeronautical
Engineering faculty of Brno University.
The wing-flaps, ailerons or flaperons and the elevator all
feature automatic self-aligning connectors, which greatly
facilitate quick assembly and de-rigging of the wings and
tailplane. The wing spars are reinforced with carbon fibre
and require no struts. They locate into each other and into
the fuselage with great precision and are locked in place
with just one steel pin. The whole operation is designed
to be extremely simple and performed in a few minutes without
tools. Once dismantled UFM aircraft can be easily transported
on a special trailer, with the wings supported alongside
the fuselage. The laminar wing profile SM 701 gives high
performance in all phases of flight
A monocoque shell structure has been adopted to provide
maximum strength-to-weight ratio and a streamlined form
of exceptional smoothness and high-gloss finish, which accounts
for the very low drag of this plane. The fuselage is largely
tubular in section with several annular bulkheads, and the
wings are a combination of a sandwich shell and a beam.
The number of parts not contributing directly to the structural
strength has been minimised, e.g. even the seats form an
integral part of the fuselage.
The load test program was based on the Czech UL-2 regulations,
however, due to the aircrafts high performance, several
tests were carried out to the more demanding standards of
JAR-22 and JAR VLA. Specifically wing gust loading and undercarriage
load tests, among others, were proved at the higher standard.
The initial arrangement of composite lay-up was calculated
manually afterwhich a three-dimensional computer model of
the wing and fuselage was created and used for the finite
element analysis of static strength using the computer program
MSC/NASTRAN.
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UFM-13
Lambada