Connecticut Corsair, Chester, CT, is restoring an F4U Corsair fighter aircraft, a complex World War II fighter plane. The company is restoring the “main beam,” or spar, using SolidWorks 3D CAD design software.
The beam is the most heavily loaded component of the aircraft, with all loads being transmitted to it, and is fabricated from over 400 parts including many forgings, extrusions and stampings. The tolerance over the 16-ft span of the beam is 0.030 in. Connecticut Corsair is reverse engineering from both original drawings and original parts.
The main beam is the most heavily loaded component of the Corsair fighter, with all loads being transmitted to it, and is built from over 400 parts.
They elected to make a mockup of the beam, using less expensive material, easily modified to include updates as it test-fits parts. The mockup serves many purposes such as a fit, form & function tool, an assembly fixture for the aircraft, and to develop fabrication processes for the airworthy components. It will be displayed at trade shows and to encourage students to study science, math, and engineering.
The first trade show at which the main beam would be featured was the Solid Works World Conference 2009 Show, which took place in early February in Orlando. As the deadline for completion of the project neared, Connecticut Corsair turned to Clinkenbeard to fabricate its mockup parts and to validate its CNC machining processes for the airworthy components. Clinkenbeard is a rapid prototyping and manufacturing company in Rockford IL that produces complex castings and machined parts using a wide variety of metals and plastics.
Clinkenbeard specializes in time-critical delivery of complex, contoured shapes in metal castings, billet parts and engineering prototypes. It offers complete CNC turning, CNC milling 3 and 5 axis, and uses the industry’s leading CNC equipment. It also is a turnkey source for machined metal castings from a 3D CAD model.
Many of the Corsair parts are quite complex and must be cast out of aluminum to support the weight of the assembly. Clinkenbeard needed to go from 3D CAD data to machined 356T6 aluminum castings in ten days or less for each of these parts.
Clinkenbeard’s CNC solution was to machine the aluminum castings quickly in one of its Fadal 40 x 20 x 30-in. 5 axis vertical milling centers. The 5th axis avoids multiple fixtures and setups, which allowed the firm to meet the critical delivery schedule.
Through use of CNC rapid prototyping, Connecticut Corsair was able to complete a 3D part, email it, and have it on Clinkenbeard’s production line within minutes. That firm made a total of approximately 35 part numbers in aluminum as well as plastic in less than three weeks.
According to Craig McBurney of Connecticut Corsair, the responsiveness and the capabilities of this CNC rapid prototype work is the single most important factor in the ontime delivery of the complex main beam for the old fighter plane.