continue in the railcar business, as competitors may have underbid on a key contract and the post-Vietnam War military build-up provided far more lucrative military contracts. Boeing Vertol products Rotorcraft AH-6 Little Bird (acquired when Boeing merged with McDonnell Douglas) AH-64 Apache (acquired when Boeing merged with McDonnell Douglas) Boeing Model 234 Commercial Chinook Boeing Model 360 (an all-composite, private venture, technology demonstrator) Boeing Vertol 107-II Boeing Vertol XCH-62 (Model 301) Boeing Vertol YUH-61 Boeing Vertol CH-46 Sea Knight Boeing CH-47 Chinook Boeing Chinook (UK variants) V-22 Osprey (built as a teaming arrangement with Bell Helicopter Textron) Boeing-Sikorsky RAH-66 Comanche Sikorsky-Boeing SB-1 Defiant Boeing MH-139 (Military variant AW139M to be American-built) Rail US Standard Light Rail Vehicle (aka the Boeing LRV) Morgantown Personal Rapid Transit Boeing Vertol 2400-series Chicago "L" cars See also Comparable major helicopter manufacturers: AgustaWestland Airbus Helicopters Bell Helicopter MD Helicopters Russian Helicopters Sikorsky Aircraft References Notes Further reading Jonathan M. Feldman (author), Gerald I. Susman and Sean O'Keefe, eds. "Chapter 18, The Defense Industry in the Post-Cold War Era: Corporate Strategy and Public Policy Perspectives", The Conversion of Defense Engineers' Skills: Explaining Success and Failure Through Customer-Based Learning, Teaming and Managerial Integration, pp. 281–318. Oxford: Elsevier Science, 1998: . External links Boeing Military Aircraft's Mobility division, headquartered at Ridley Park, PA Rotorcraft Systems Helicopter manufacturers of the United States Defunct rolling stock manufacturers of the United States Manufacturing companies based in Pennsylvania Companies based in Delaware County, Pennsylvania 1960 establishments in Pennsylvania