Developed in 1949, the K-225 is the same as the Kaman K-190 except for engine and performance.  CAA certificated, 11 were produced with the primary use of crop dusting.  In March 1950, three K-225s were delivered to the United States Navy and Coast Guard for evaluation.  Of those delivered, the K-225 performed the first loop by a helicopter.  The Navy took the K-225 into service, modifying it under the designation of HTK-1. This version used a reciprating engine.

Source:  Hirschberg, Michael. "The American Helicopter" (2000). Page 58.

Overview

Data on design, manufacture and status

Design authority: Kaman Aircraft Corporation

Primary manufacturer: Kaman Aircraft Corporation

Parent type: Kaman K-225

Aircraft status: No longer flying

Configuration

Primary flight and mechanical characteristics

VTOL type: Helicopter

Lift devices: 2 in Synchropter configuration

Crew required: 1 in Single seater arrangement

Landing gear: Wheels (non-retractable)

Key Characteristics

Data on key physical features

Aircraft Details

Data on aircraft configuration, weights, flight performance and equipment

References

References and sources used

Helicopters & Autogyros of the World
Paul Lambermont, Anthony Pirie
Cassell & Company Ltd., 1959 (page 314)
Book

S-47 | S-47/R-4 Helicopter
Vinny Devine
Sikorsky Archives | Product History, Sep 19, 2017 (page 3)
Website
Very thorugh description and details of the R-4 series helicopter

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Related Public Resources

Resources related to the K-225 (YH-22), provided by public sources across the internet.

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