Alan Forsythe and Chuck Green invented the Valkyrie line of Freon-propelled rockets in the late 60's. The rockets utilized the vaporization of liquid R-12 Freon (diflurodichloromethane) to provide thrust. To market their invention, they started Vashon Industries, Incorporated in 1968. The company was located on Vashon Island, WA, an island in Puget Sound.
Both Alan and Chuck had professional backgrounds in rocketry. From 1959-1962, Alan was employed by JPL where he worked on the Ranger project which sent the first U.S. unmanned spacecraft to the moon. Chuck worked at the U. S. Naval Ordinance Test Station in China Lake, CA from 1959-1964 where he was Head of the Propulsion Technology Branch. While there, he lead an effort to design a Freon-based engine steering system for the Navy's Polaris missile. The two inventors met while working at Rocket Research Corporation (later part of Olin Corporation) in Seattle. Between 1965 and 1968 they worked on a low temperature gas generator to inflate the original escape slides for the Boeing 747 (which used R-22 Freon for inflation). In their free time they conspired to develop freon-propelled rockets in Chuck's garage.
By the fall of 1968, Vashon Industries had made its debut and Alan was involved full time in the model rocket business. Within less than a year, Chuck also joined Vashon full time as the company president. Production of the freon-propelled model rockets began with orders for parts to build 1000 rockets. By the time the company was sold to the Damon Corporation in 1971, production had exceeded 100,000 units. It is interesting to note that on paper, Vashon merged with Estes, under the Vashon Industries name, which was quickly changed from Vashon to Estes. One reason for this name shuffle was so that Estes could exploit Vashon's entries into the marketing arena including chain stores such as Sears and Neaman-Marcus. Alan and Chuck sold Vashon for stock in the Damon Corporation (which doubled in value shortly after the sale). The sale was a great relief to the owners (and ~25 shareholders) who were facing imminent cash flow problems stemming from late-paying toy wholesalers. Alan and Chuck were given a two year contract by Damon to transfer their technology to Estes. In 1972 operations were progressively moved from Vashon, WA to Estes' plant in Penrose, CO. During this time Alan and Chuck developed the Estes Cold-Power engine, which slid into conventional Estes "paper-tube" rockets and used a large spiral spring to eject the parachute. The move of Vashon operations to Penrose was completed in 1973, which coincided with the end of the contract between Damon and the original inventors.
Free from their toy company responsibilities and problems, Alan and Chuck started Green Forsythe and Company which used their extensive engineering and business backgrounds to provided consulting support to industrial companies in the Seattle area. Over the next three years they designed a number of products for the heavy-truck industry. In 1976 they started GT Development Corporation which manufactures products for the truck market. Alan and Chuck still run the company to this day, employing over 200 workers.
During the Vashon Industries era, all parts for the freon-propellant engines were purchased from outside vendors. Assembly of the parts was performed at the Vashon plant. The engines consisted mainly of polished aluminum tubes and end bells. Four bells were used per rocket. The nozzle and the threaded fittings were crimped or staked into the bells prior to their being inserted into the aluminum tubes. After a thermal epoxy had been placed in the ends of the engine tube, the bells were driven in by machine and the tube ends were rolled over to further insure that the bell would never pop out. Two of the bells also were required to build the separator which was screwed to the top of the engine.
The filler tube in the side of the engine consists of a rubber valve similar to those used in inflatable sports balls (e.g. footballs, soccer balls and basketballs). The vent valve was more complicated, consisting of a small aluminum poppet inserted through a hole in the engine, followed by a rubber washer, a steel washer, a spring and a snap ring inside the rocket chamber to hold it all together. The head of the poppet was exposed, and had a short blind hole also exposed so that the rocketeer could insert a wire and vent the engine during loading by tilting the poppet. This helped assure that the engine was fully loaded with fuel and would provide a good high flight. When it was full it would exhaust a visible cloudy fog very much like the big rockets at Cape Canaveral. The valve also automatically opens when the tank pressure exceeds about 80 psig to protect against over-pressurization.
A nozzle plug kept the engine sealed while fueling. The plug used a standard O-ring ( size -002 neoprene) to make the seal. Prior to launch, the plug was held in place by either a metal safety pin, or a thin electrical wire. For manual launches, one merely pulled the pin, releasing the plug. For more sophisticated launches, a nozzle plug with electrical leads was used to fire the rocket from a few feet away. The wire leads connected to a thin wire which held the plug in the nozzle. Although the wire resembled nichrome, it was actually pyrofuse. This material is a combination of Platinum and Aluminum in intimate mechanical contact. When heated past a critical temperature, the metals fused exothermically. By connecting the ends of the plug wires to a battery, the pyrofuse would heat up and melt or disintegrated, allowing the plug to be released.
Figure 1. Schematic of a Vashon "cold power" rocket from the kit instructions.
Al designed the separator mechanism which used spring steel to grip the aluminum parachute tube when the engine was pressurized with propellant. Paper discs were used to delay the depressurization of the separator spring (and deployment of the parachute) following depressurization of the engine compartment. The original Valkyrie rockets used an all-aluminum 3"-long parachute tube. A 4.5" version was available separately to provide more room in the parachute compartment. The parachute tube was changed to a paper tube (taped to a ¾" section of metal tube) in the year before the sale to Damon. This change had several advantages including lower production costs. The short metal tube was the same tube that was used to construct the separator. The rest of the parachute tube was paper which was much cheaper than aluminum. Using the paper tube also allowed the rocket to be decorated more easily, and provided an impact absorbing section, should the rocket impact before parachute deployment.
Vashon produced four types of engines. Most familiar are the 4.5"-long V-1 engine (Vashon # ENG-802 or #5075) and the 8.5"-long V-2 engine (Vashon #ENG-801 or #5001) which are both 1" in diameter. The V-2 engine was used only in the Valkyrie-2 kit. A shorter 2.5" V-1/2 engine (Vashon #ENG-803) was also available in the earlier catalogs, but it does not appear in Vashon's last catalog. This engine was sold separately for use in a strap-on clustering arrangement. Two of the 803 engines could be taped onto the booster stage for added thrust at take off. A slimmer 5/8" diameter by 4" long, J-33 engine was introduced around this time for use in the Shrike and XS-1 Styrofoam gliders. This engine was filled through the exhaust nozzle. The vent valve was on the aft end of the engine.
A hobbyist could also dabble in clustering and staging of Valkyrie engines by buying the Staging Adapter Kit (Vashon ADK-801 or #5060) which included their Staging and Clustering Technical Report. A staging kit which included the separator was also listed in catalog 3 with the part number SEP-802. The metal tube included with the staging adapter was the same piece used to cover the nozzle on the Sergeant and Sandpiper semi-scale kits (but was later shortened on the scale kits to make inserting the firing pin easier).
It is interesting to note that, in all the old Vashon catalogs, an exchange policy for the engines is given. One might infer from this that their reliability was suspect. This was not the case however, as one of the inventors attests to having flown the same engine over 100 times.
Four catalogs and many flyers were produced by Vashon. The first three catalogs are 3.6" wide and 8.5" tall and have a color picture of the Valkyrie-2 on the cover. They can be distinguished from one another by looking at the page opposite page 8, where a catalog number 2 or 3 will be printed, or a late 60's date will be given (catalog #1). These catalogs were included in some of the mail order kits. Vashon's last catalog was a more elaborate 5.3"x8.3" edition having a black cover with color pictures of the earth and the moon on it. No dates or numbers appear on this catalog, although some have a sticker with 3001 stuck on the cover. The wider catalog is the only one that lists the (Valkyrie-1 based) parasitic glider/rocket combination kits (X-13, AstroGnat and Baron), the two semi-scale missile kits (Sandpiper and Sergeant), the two Styrofoam glider kits (Shrike and XS-1) and the two-stage Valkyrie Viking kit (which used two stacked V-1 engines and the previously mentioned staging coupler). All of these kits were continued by Estes after the merger except for the Viking. Estes did sell the staging coupler so that one could construct the Viking out of parts from two Valkyrie-1 kits. The most impressive flyer produced by Vashon was a four page color brochure entitled "What's Up at Vashon", that showed their entire line of rocketry products.
Figure 2. The Vashon Viking two-stage rocket description from Vashons's last catalog.
The Vashon kits were initially available by mail order. Later the kits were available in chain and department stores. The "M" in some of the kit numbers signified mail order packaging. As Vashon Industries grew, and later merged with Estes, the kit numbers went through several changes. As an example, the kit numbers for the Valkyrie-1 and Valkyrie-2 are given below:
The Valkyrie kits did not appear in the Estes catalog after 1975 (although some of Estes' Cold Power convertible rockets were available for one more year). With the advent of the knowledge that the RP-100 propellant (i.e. R-12 refrigerant) destroyed the ozone layer, the cold power line was retired. A line of cold power race cars were available from 1975-1977. They used the J-33 engine which Estes renamed the XR-100 motor.
One perceived advantage of the freon-propelled rockets was that they were not an incendiary device. By comparison, conventional contemporary model rocketry fell under the jurisdiction and restrictions of each States' fireworks codes. Nonetheless, a large portion of Chuck's time was spent defending the legality of the Vashon metal rockets. To their credit, the Valkyrie rockets were the only devices that passed the full scrutiny of the New York bomb squad. Vashon also won packaging awards for their display boxes which showed the various parts of the Valkyrie-I through a cutout in the color box.
During the heyday of Vashon Industries, a 30 second television commercial was made to market the rockets. It showed a slow motion lift off of a Valkyrie rocket including close ups of condensed ice sloughing off the sides of the rocket engine as it lifted off the pad. The sequence was so realistic that the FCC complained of false advertising. It seems they thought Vashon was using footage of a real rocket launch to sell their model rockets. The owners were happy to inform the authorities that all the footage was taken from the launch of a Valkyrie model rocket.
As previously stated, vashon rockets used R-12 freon which is no longer being produced owing to its deliterious effect on the ozone layer. However, other ozone-safe gases can be used to fly Vashon rockets today. My son Matthew did a science project to determine the thrust from three different propellants. What he found ( See Matthew's Web Page) was that air-brush propellant and the current automotive referigerant, R-134a, seemed to work fairly well. I would recommend that one wear safety goggles and gloves while fueling these engines (and I cannot be responsible for any accidents you have while playing with these items!!). Higher pressure freons should bleed off (assuming the relief valve is working properly)until they cool the engine to the point where their pressure falls below the relief valve pressure of 80 psi.
Be aware that section 608 of the Clean Air Act states that it has been illegal since November 15, 1995, to knowingly vent substitutes for CFC and HCFC refrigerants during the maintenance, service, repair and disposal of air-conditioning and refrigeration equipment. In addition, on June 11, 1998, EPA proposed a regulation to fully implement this statutory venting prohibition, (See http://www.epa.gov/spdpublc/title6/608/608fact.html#noventing ) except for "de minimis" quantities of refrigerant. However, since a Vashon rocket is not a refrigeration device, one could argue that these rules do not apply to rocketry. In any case, the use of air-brush propellant, which is always released into the atmosphere, is a safe bet. It can be purchased in the model-building section of Wal-Mart or at a hobby shop.
IMPORTANT NOTICE: Within the last year or two, the formulation of Walmart's air brush propellant has changed from inert ingredients, to a mixture that contains flammable components (propane I believe)!!!! Please do not use this new flammable propellant, as the result could be extremely dangerous for you and your rocket associates. Always check the label of the propellant you are considering using and stay away from those with flammable components.
I replace the nozzle head on the can with a head from a can with a nozzle extension tube (e.g. carburator cleaner, WD-40, or TriFlo lubricant) to allow dispensing into the rocket engine. The fill tube from the Vashon kit can be force-fit into the nozzle head to produce a flexible fill line. Since the engine must be filled with liquid, invert the air-brush propellant can so that the liquid flows out the nozzle. The original RP-100 propellant cans had an internal tube that dispensed liquid from the bottom of the can, so that the can could remain upright.
Good luck with your Vashon rocketry pursuits! If you have any stories about fly Vashon rockets, please send me an account of your experiences!
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