(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 be clear.
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 two fold:
  1. Quality control is paramount in producing helicopter components. In-house production is far easier to monitor.
  2. 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 costs.
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.


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


Photo #1.

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?)
Photo #2.
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 design.
Photo #3.
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.)
Photo #4.
A ¼ rear view of the tanks in their respective positions in the HELICYCLE airframe.
Photo #5.
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 #6.

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.
Photo #7.
The "drag" or bottom half of the sand mold.
Photo #8.
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!
Photos #9 & 10.
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.
Photo #11.
Here we're pouring 70 lbs. of 319 aluminum into the mold at 1250° F.



Photo #12.

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.
Photo #13.
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.
Photo #14.
A temperature check using an infrared sensor.
Photo #15.
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.
Photo #16.
Removing the upper mold half.
Photo #17.
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).

   Specifications  FAQ  Price  Contact  Flying Helicycle's  Factory  Shows  Pictures/Video  Builders  Home

Eagle RnD 2512 Caldwell Blvd. Nampa, Idaho USA 208-461-2567 Fax 208-454-3752

Hit Counter