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| LZ-5 | |
|---|---|
 | |
| Role | Utility helicopter Type of aircraft |
| Manufacturer | Doman Helicopters |
| Designer | Glidden Doman |
| First flight | 27 April 1953 |
| Status | Prototypes only |
| Number built | 3 |
TheDoman LZ-5 was autility helicopter developed in theUnited States in the early 1950s by Doman Helicopters Inc. of Danbury, Connecticut. Despite the procurement of international manufacturing agreements, no series production of theaircraft ever occurred, and only threeprototypes were built. Two of these were purchased by the United States Army as theYH-31, but eventually becomingVH-31.[1]
Like the precedingLZ-1 throughLZ-4, the LZ-5 utilized designerGlidden Doman's unorthodoxgimbaled rotor head system, which featured the elimination of rotor hinges and dampers and included blades of soft-in-plane dynamic design. The servo control system was entirely contained within the rotor head, with no external oil tanks or plumbing. The tail rotor was also hingeless and free floating to eliminate stresses in rapid tail rotor turns. In other ways, it had a conventional helicopter main rotor and tail rotor configuration. The pilot and co-pilot were seated over the engine, which was in the nose, and a six-passenger compartment was located behind them. The engine was cooled by exhaust ejectors, producing an energy saving that increased payload by 800 pounds. The aircraft featured wheeledquadricycle undercarriage, the main units of which carried dual wheels.[citation needed]
The first prototype (registrationN13458) flew on 27 April 1953, and by the end of 1955, two machines had been delivered to the Army (52-5779 and52-5780). Eventually, theArmy concluded that they had no requirement for an additionalpiston-powered helicopter model in this size category, and no further order was placed. After extensive flight testing and pilot training by the Army, one of the prototypes was taken over by the Navy for ahelicopter flight research program at the Patuxent River Naval Air Test Center. Later thataircraft was re-purchased by the Doman company and used in its commercial sales efforts.[citation needed]
Doman continued with development, building another LZ-5 aircraft in a joint venture withFleet in Canada. The LZ-5 helicopters were simultaneously Type Certificated in the U.S. and Canada in 1954. The third helicopter flew extensively in Canada under Canadian registration CF-IBG and in the United States, France, and Italy under U.S. registration N812. It flew in the Paris Air Show in 1960. This aircraft was also modified with the installation of full blind flight instrumentation, which was demonstrated extensively in the effort to sell it as atrainer. The aircraft thus equipped was advertised as the D-10. The planned production version would have been modified with a turbo-charged engine and designated as theD-10B. Doman sold production rights for military versions toHiller and for the Italian market toAmbrosini.[citation needed]
Ultimately, none of these plans were to eventuate, and the LZ-5 never entered production.[citation needed]
After the demise of Doman Helicopters Inc. in 1969, the second Army prototype was taken to California for display at theHiller Aviation Museum, founded byStanley Hiller, Jr. That helicopter was returned to Connecticut in 2009 and is on display at theNew England Air Museum in Windsor Locks, Connecticut.[2]
Data from Jane's All the World's Aircraft 1956–57[3]
General characteristics
Performance