R.J. Enstrom Corp. formed Menominee, Michigan, 1959 to produce F-28 3-seat helicopter flown as 'breadboard' prototype November 1960. Operations ceased February 1970, but restarted as Enstrom Helicopter Corp. 1971. Since then 915 helicopters delivered in 7 main versions, but company acquired successively by Pacific Airmotive, Bravo BVC (Netherlands), US group headed by Dean Kamen and Robert M. Tuttle, and in 1990 by investment group based in LA.