Kaman K-225
| Kaman K-225 | |
|---|---|
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| Type: | Agricultural helicopter |
| Design country: | |
| Manufacturer: | |
| First flight: |
July 1949 |
| Number of pieces: |
approx. 20 |
The Kaman K-225 is a Helicopter equipped with a Flettner double rotor made by the US company Kaman Aircraft Corporation .
history
K-125
Charles Kaman designed his first helicopter in the mid-1940s. The K-125, flown for the first time on January 15, 1947, was the first helicopter developed in the USA to use intermeshing rotors configured as a so-called Flettner double rotor . A tail rotor to compensate for the torque can be dispensed with, which has advantages such as less downdraft and easier controllability. Also of Anton Flettner developed on the rotor blades attached so-called servo-flaps ( servo flaps an invention which should reduce the control forces and stabilize the rotor blades -). A Lycoming piston engine with 125 hp was used as the drive. The K-125 was uncovered, had a round cross-section and consisted almost entirely of a steel frame, it offered a seat. Only one prototype was built.
K-190
The K-125 formed the basis for the K-190 multipurpose helicopter, which flew for the first time in December 1948 and was produced in small numbers with a 190 hp Lycoming O-435 piston engine. The K-190 was the first Kaman helicopter to receive a type certificate. Like its predecessor, this model was not disguised, but it was built much more angular and consisted of a tubular steel frame, it offered seating for two people in a row. Few examples were built.
K-225
The K-225 was further developed from the K-190, which retained the structural design of its predecessor and received a Lycoming O-435-A2 piston engine with a continuous output of 225 hp. Behind the pilot's seat there was a bench with three seats, the cockpit in the footwell was glazed, otherwise open. The prototype and the first ten series machines were configured for “spray use” in agriculture. The state of Mississippi purchased a special version with an enclosed cabin for use in the field of oil exploration. The Turkish government bought some copies for training and agricultural use.
In July 1949, the US Navy purchased two K-225s at a price of $ 25,000 each to gain experience with the unconventional rotor configuration and the rotor's novel servo flap system. The machines, designated by Kaman as XHK-225 (Experimental Helicopter Kaman 225), have undergone extensive testing at the Naval Air Test Center (NATC) in Patuxent River, Maryland.
On December 10, 1951, a converted XHK-225 flew for the first time, in which the piston engine had been replaced by a Boeing 502-2 (YT-50) turbine with 175 WPS, making it the world's first helicopter operated with a gas turbine . Despite the lower performance, the flight performance was significantly better, as the turbine weighed only half as much as the piston engine. The XHK-225 was then further developed into the Kaman HTK .
Technical specifications
| Parameter | Data |
|---|---|
| Seats | 3 |
| Rotor diameter | 11.58 m |
| length | 7.01 m |
| height | 3.35 m |
| Dimensions | 816 kg |
| Power (piston engine) | 168 kW |
| Power (turbine) | 130 kW |
See also
literature
- Howard Levy: Kaman Helicopters. In: Airplane Monthly, June 2006, pp. 61–75.