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Variable Capacity Ejection Canister from Pratt Hobbies |
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2002 Archived News by Pratt Hobbies
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Tuesday, April 02, 2002 |
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HERNDON, Virginia USA -- Pratt Hobbies has added to its line of unique and useful rocketry accessories by introducing the Variable Capacity Ejection Canister, or VCEC.
Based on the popular WEC-1A Ejection Canister, this prewired plastic container allows the user to select the amount of black powder that is appropriate for his application. There is no need to cut or modify the Canister, just slide the compressible stopper down until it touches the powder charge.
Literally thousands of WEC-1 and WEC-1A Ejection Canisters have been used by rocket fliers in the past four years. However, the 1.5 gram capacity of the Ejection Canister was too small for some larger models, or applications that required more force, such as shear pins. Some users would connect two canisters to the same control output, or mounting a single canister in a 35mm film can filled with BP. Pratt Hobbies has been looking for an elegant solution to the problem for almost a year. Larger snap-top containers have been tested, as have various flexible sealed bags. The ideal solution has emerged in the VCEC.
The VCEC consists of a thick-walled polypropylene plastic tube, sealed at the bottom. The filament igniter is inserted through a hole in the bottom, and secured in place with a special adhesive. This is the same igniter used in the WEC-1A canister, and does not require a LEUP, special storage or hazmat shipping. Each igniter is continuity tested before packaging, and comes with stripped and tinned wire leads.
The compressible stopper is the elegant part of the VCEC. The stopper is a plastic spongelike material that is sized to fit the tube. When pressed into place, it expands and grips the walls of the tube, providing a positive seal. The seal is tight enough to prevent any powder leakage, but loose enough to provide a clear path for the ejection gases, keeping the tube intact. Since the stopper can be positioned at any point inside the tube, the user can determine the exact amount of BP necessary for his application. It is not necessary to cut or drill the tube.
Variable Capacity Ejection Charges are single-use devices, packaged in sealed bags. They cost $2.00 each, and can be shipped without hazmat restrictions. For more information and to order, check out the Pratt Hobbies catalog at http://www.pratthobbies.com. |
