WHY IS IT SO DIFFICULT TO GET ANY
CERTIFIED QUALITY HELICOPTER INTO PRODUCTION?
(The Problem & An Example of a Solution)
The easy answer would be to send you on a tour through the Bell
Helicopter or Robinson Helicopter production facilities. Seeing
is believing; when you finished the tour, your conclusions would
You would definitely see that producing helicopters requires being
in many types of manufacturing businesses, from plastic forming
to aerospace machining. Eagle R & D has no less difficulty in this
area, because every manufacturing discipline needed to create an
R-22 is also necessary to produce the HELICYCLE©. There are 400
lbs. of materials in the HELICYCLE and about 700 lbs. of materials
in the R-22. The sheet metal in the R-22 is replaced with fiberglass
in the HELICYCLE and the wiring is more complex, but the HELICYCLE
has more components in its transmission and rotor hub … so the problems
are quite similar.
You might well ask why a true helicopter manufacturer
is forced into creating his product almost entirely in-house and in
the process forced into so many different businesses. The answer is
Quality control is paramount in producing helicopter
components. In-house production is far easier to monitor.
It's very costly to have certified quality aircraft
parts produced outside. Parts produced outside also add a second
internal recheck of tolerances, which again significantly increases
It's important to recall that the grand purpose
of the HELICYCLE is to produce it for 1/5th the price of the R-22.
This goal can only be achieved by cutting the cost of each part
in the machine by ½ what we were able to produce for in the mid-80's.
(Building the Exec helicopter at Rotorway). Achievement of this
kind of cost reduction necessitates building in-house virtually
everything but AN hardware. Each piece and part in the machine is
carefully cost analyzed, it's processes are timed and documented.
Tooling to produce it is optimized for the volumes involved. Written
production procedures add to the efficiencies. Effort is made to
continuously reduce cycle times.
THE FUEL SYSTEM IS
Tooling projects to get the HELICYCLE in production have been
going on now for about three years (from 1997 - 2001). The most
recent project started in November 2000 and was completed in 3
½ months. The fuel system was not the most difficult area of tooling,
however it is of vital importance from the standpoint of crash
worthiness and affordable cost.
The fuel tanks in any aircraft are prone to rupture in a crash,
therefore they must be formed out of a material that will deform
and still not rupture. One of the better materials meeting this
criteria is a cross-linked plastic polymer which is molded in
a 600° oven using a process known as rotational molding.
There are numerous rotational molders around the
U.S. producing parts for everything from garbage cans to water tanks.
The problem for Eagle R & D is not one of supply. The problem's
are quality control and cost. By producing our tanks in-house, we
can control the quality and the cost is reduced by designing the
tooling, oven & molding equipment specifically for our product.
How we went about doing this is shown in the photo
story which follows. The bottom line is a high quality fuel system
for ½ the normal price.
PHOTO PAGE I. Creating
the Rotational Molding Casting Tools
The first step is to design the configuration of
each tank which will be used. It must fit in the space available
and the method of attachment & a number of other engineering considerations
must be addressed. For instance, in a 20G impact, the top fuel tank
will weigh 820 lbs. It must be secured to withstand this loading.
The parting line where the molds will be formed into two halves
must be established and the shrinkage's of all processes calculated.
This is a tricky process on complex configurations like those pictured
here. The process of shaping the tanks in wood, foam, fiberglass
and Bondo (all used here) requires pattern making skills. The eight
separate tools shown here combine to produce four separate tanks.
(Can you match them up?)
Step two is to lay-up a fiberglass molding tool
about 3/8" thick over each master pattern. Great care is taken to
preserve the draft angle integrity. The part will not be able to
be extracted from the silica sand mold if this is not the case.
The flange areas of the tool are another example of precise work
to insure against warpage, which would ruin the alignment of the
parting lines. The speed of the lay-up, temperature, and the resin
catalization are factors which must be monitored in order to create
a molding tool which will faithfully reproduce the original engineering
The last process is to pour off the aluminum castings
in which the plastic polymer will be molded. The inner cavities
of the casting tools are carefully finished to provide an attractive
surface on the plastic part. The castings are machined to match
on the parting lines. A dowel pin system insures accurate alignment
and a quick release clamping system holds the two halves together
during the molding process. A lot of elbow grease goes into these
tools from the time they are poured, until they are ready for production.
(The process of making the sand molds and pouring the castings is
shown On Photo Page II.)
A ¼ rear view of the tanks in their respective positions
in the HELICYCLE airframe.
A side view of the tanks. The top tank drains into
the lower tanks on each side. Special fittings are provided in the
fuel system kit for this purpose. A unique method of supporting
and attaching the tanks in the airframe is utilized. (The process
is covered in the fuel system installation video.)
PHOTO PAGE II. MAKING
The "cope" or top half of the sand mold. We are
using a molding process here known in the foundry business as "air-set".
A three part chemical binder causes the sand to harden in a few
minutes. The registration and detail transferred using this process
is exceptional and it insures that the metal casting will accurately
reproduce the pattern.
The "drag" or bottom half of the sand mold.
Here the cope and drag are being closed. The alignment
pins show on either side of the mold. The pins insure accurate cope
and drag registration. This mold weighs 700 lbs. The largest in
this set was 1100 lbs. Eight parts required 16 cope and drag halves,
so a considerable amount of sand (several tons) was consumed. (Moving
this amount of sand about 4 times in one week caused son Rodney
to admit he was tired, another first!
The casting is chipped out of the mold with an air
hammer. Photo #10 clearly shows the gating and risers with exothermic
sleeves, which allow us to achieve solidification without any shrinkage
or porosity problems.
Here we're pouring 70 lbs. of 319 aluminum into
the mold at 1250° F.
PHOTO PAGE III .
MOLDING THE PARTS
A view of the oven used to heat the molds. The in-house
designed burner provides 1 million BTU to enable us to quickly achieve
temperature stabilization at 600° F.
The 2-axis molder runs two parts simultaneously
for added efficiency. The molder was designed and manufactured in-house
specifically for use with our proprietary tooling.
A temperature check using an infrared sensor.
Cooling the tools prior to de-molding. Processing
cross-linked polymer is more demanding. Finalizing the parameters
of mold rotation, heating and cooling cycles and release preparation
takes time to refine into a repeatable, procedural cycle. (Another
written procedure which must be followed by the operator and monitored
by Q. C. personnel.) The HELICYCLE procedural manuals now total
14 and will be up to 20 or so by the time every production procedure
is completely documented.
Removing the upper mold half.
A view of the still hot upper fuel tank.
The HELICYCLE is
the smallest cocoon you can strap yourself into, capable of 95 mph
cross-country flight, terminating in a pinnacle landing at 10,000
ft. (All for the price of a pickup).