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New engine design a winner with PowerSHAPE |
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DeltaHawk Inc., based in Franklin, Wisconsin, has developed a powerful all-aluminium diesel engine for military drones - the un-manned aircraft used for surveillance and other dangerous battlefield operations. Diesel engines are simpler, more fuel efficient and more rugged than the petrol and turbine engines currently used. |
The DeltaHawk engine features an integral head and block. This saves as much as one-third of the weight of more conventionally designed diesels but presented serious challenges to the patternmakers that created the tooling. DeltaHawk entrusted its components to the expertise of two nearby firms; Central Pattern Corp., which designed and built tooling for a dozen engine components, and Waterford Aluminum Co., the foundry which made the sand castings.
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Mark Patrick at Central Pattern did some of the tooling design and CAM programming. Users of Delcam software since 1995, the designers at Central Pattern had confidence in PowerSHAPE and the support staff at Cad Cam Systems. "If any errors occurred, it would have meant excess metal that has to be ground away by hand," he explained. "It would also mean that parts would have to be spot-matched for proper fit during assembly." Misfits could mean a great deal of hand work for assemblers as well as reliability and maintenance problems later in the engine’s life cycle. What’s critical to the foundry is the "close-over", the fit of the molding tools for the outside of the engine when closed over the mould and cores for the inside. The DeltaHawk engine required more than a dozen cores. Despite the complexity, the tooling held together tightly."For CAD, we used PowerSHAPE, which was created for this kind of work," said Mr. Patrick.. "For something like the DeltaHawk, we couldn’t rely on the traditional methods. This tooling had to be done right to the data. No interpretation was allowed, not even on the smallest fillets." |
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"We probably could have designed this tooling with other software packages but it would have taken 15% to 20% longer." Mr. Patrick continued. "The engine block and its integral components had a total of 1,400 surfaces".
Time was of the essence. The patterns for the DeltaHawk engine were designed and built over a period of ten weeks. It currently holds more than 100 orders for engines with a value of about $1.9 million from the military and experimental aircraft builders.
