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Product:
Testing
KAHU
& WADEAero - a designers perspective
Preamble
History
records the orderly development of the Gyroplane. The concept
is not new and the physics applied conform to the natural
laws of science. Resultant geometric configurations therefore
have commonality and ultimate designs are the result of practical
needs and restrictions. In this equation are the considerations
of materials the end use of the plane and the market value.
At all times it needs to meet the strict legal requirement
of the licensing authority in the area of its intended use.
KAHU
by ASI has been designed with these factors in mind and the
resultant form is an attempt not only to provide a safe and
practical plane but also one that is aesthetically pleasing
to the eye. At all times the various authorities have been
consulted and experts in the individual and various disciplines
been engaged. The combined use of CAD packages provided the
ultimate detail from which the final design emanated.
Procedure.
Plane
Due to the experimental nature of the plane and the desire
to keep the weight within the Microlight category it was decided
at the outset to make the best use of composite materials
as NZ has a reputation for being leaders in this field. It
was also apparent that in any event considerable time would
need to be expended in the testing of panels and the selection
of suitable matrixes. In some areas it was considered prudent
to use typical aeronautical practices of aluminium and chromemoly
supporting structures rather than composites.
Detailed
component drawings were developed and components subsequently
fabricated. A plug was fabricated and moulds developed for
the body form.
Calculations determined the various moments and as a consequence
considerable time was expended in achieving this. Subsequent
trials reflected that the time and effort was well spent.
Where practical 'off the shelf "components were used.
In some instances automotive components have proven to be
adequate and the 'WADEAero' rotary engine forms an integral
part of the schedule.
Engine
The engine is a modified 13B Mazda for aeronautical use. It
was therefore determined at the outset that the engine should
be subjected to various rigorous trials not only on a dyno
but also in a road going car with stopping and starting and
with various loads.
A calibrated load cell was purchased [photo to come] and has
been used in all the subsequent thrust /line pull tests. It
has also provided us with an accurate means by which to record
the resultant reaction of any re-calibration of the engine
ECU. Line pulls of 675 Lbs at 5500rpm are standard.
PSRU
As a consequence of the engine development it was considered
that a matching PSRU should be designed. The construction
being those components normally used in a Mazda transmission
and despite being modified have shown under use (now in excess
of 50 hrs) that the fabrication will withstand thrusts of
up to 850 lbs without undue stress or the additional requirement
of external lubrication.
Composite
Structure
In the design of any object one considers the likely subjective
forces. In the case of Kahu because of the geometric design
configuration and the monocoque construction and the very
nature of its uniqueness a designer's lament prevailed. As
a consequence we now find that the resultant form after curing
has provided structural integrity beyond that required in
usage. Weight reduction/savings will be the result. What it
has shown very clearly that by the careful selection of materials
and attention to resin ratios a very lightweight structure
may be achieved.
General
As with all new experimental craft a test pilot of considerable
reputation has conducted and will continue to conduct such
trials are deemed necessary so as to meet the NZ CAA requirements
for this type of craft. The CAA have provided a certificate
of authority to do this.
At this point in time we are conducting flying trials in accordance
with the test pilots schedule.
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