Kaman K-225 "Mixmaster"
Historical Information:
Kaman Aircraft company built three K-225s under a Navy contract (NOa(S)-10876) to test and evaluate the type and the Coast Guard purchased one of these, CG-239, in early 1950. It was delivered to Air Station Elizabeth City on 18 March 1950 where it underwent testing and evaluation.
The K-225 used two two-bladed intermeshing rotors, thereby eliminating the tail rotor. The blades were made of laminated spruce covered with fabric and dope. Control was achieved through the use of servo flaps located behind the trailing edge of each blade, actuated by a series of push-pull rods. Kaman later added a gas turbine engine to a K-225, making it the first rotary-winged aircraft so powered.
On 11 May 1950, CG-239 went into the workshops at Elizabeth City after undergoing 120 flying hours. After this, it was apparently "little used" except for pilot refresher training. CG-239 was transferred to the Navy on 22 March 1954 and was later sold into private hands. It crashed on 1 October 1955. Although there were no injuries, the helicopter was completely destroyed.
No caption/date/photo number; photographer unknown.
"USCG Kaman HK-225 helicopter at U.S. Coast Guard Air Station Elizabeth City, N.C."; 30 January 1951; no photo number; photo by PH Philip A. Biscuti, USCG.
No caption/date/photo number; photographer unknown.
Sources:
Arthur Pearcy, U.S. Coast Guard Aircraft Since 1916 (Annapolis: Naval Institute Press, 1991), pp. 320-321.
Gordon Swanborough & Peter M. Bowers. United States Navy Aircraft Since 1911 (Annapolis: Naval Institute Press, 1990) (revised), pp. 432-435.