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Description
| Manufacturer: | Bell | |
| Base model: | H-40 | |
| Designation: | YH-40 | |
| Designation System: | U.S. Air Force | |
| Designation Period: | 1948-Present | |
| Basic role: | Helicopter | |
| Status: | Prototype | |
Specifications
| Not Yet Available |
Known serial numbers
Recent comments by our visitors
| David Hatcher Enterprise, AL | Thanks Matt for the picture! 10/02/2008 @ 05:32 [ref: 22781] |
| David Hatcher Enterprise, AL | Thanks Bill! Gee and I was just by there last March going from the NASM to Kitty Hawk. Thanks again for the location and picture! Dave 10/02/2008 @ 05:30 [ref: 22780] |
| Bill Lincoln , NY | Currently, the Bell Model 533 is on display at Fort Eustis, VA outside of the Aviation Applied Technology Directorate (AATD) building. I, too, wish I had a good photo of it. 04/19/2007 @ 13:40 [ref: 16232] |
| David Hatcher Dothan, AL | Does anyone know where the Model 533 is today? Pax River at the Navy Test Pilot School or at NASA? I would appreciate a recent digital photo, or any other UH1s that may be "displayed" even those on a stick! 12/04/2006 @ 14:37 [ref: 14909] |
| David Hatcher Dothan, AL | In 1959, the Army experimented with various rotor systems and methods of drag reduction for helicopters. Bell modified the first prototype YH-40 s/n 56-6723 as a test-bed which Bell called the Model 533. These modifications included a cambered vertical tail surface, streamlined fairing for the rotor system, flush air intakes, aerodynamic cross-tubes for landing skids and new hinges for the doors. Even the stabilizer bar and replaced with a variable-tilt rotor mast (?) in order to maintain the fuselage in low-drag attitude. The Lycoming T53-L7 was replaced with a 1.100 shp Lycoming T53-L-9A and then with a 1.400 shp Lycoming T53-L-13 turboshaft.
Several different two, rigid three and four bladed rotor types were tested. Eventually, two Continental J69-T-9 turbojets were installed on each side of the fuselage. On January 17, 1964, the helicopter achieved a speed of 338km/h in level flight using both the 1.100shp Lycoming T53-L-9A shaft-turbine, plus the J69s. The next modification was two small sweptback fixed wings which now made it “a compound helicopter”. The J69-T-9s were replaced by 765-kg J69-T-29s. On October 15, 1964, the Model 533 was the first helicopter to exceed the 200 knots. In 1968, two 1490-kg Pratt & Whitney JT12A-3 turbojets at the end of short stub wings, and in May 1969, Bell announced the aircraft had attained 508km/h. 12/03/2006 @ 06:45 [ref: 14900] |
| David Hatcher Dothan, AL | The US Army procured 6 YH-40 in 1956, Army serial numbers 56-6723 thru 56-6728 (Bell serial numbers 4 thru 9)
56-6723 became the Bell Model 533, experimental compound helicopter 12/01/2006 @ 10:54 [ref: 14888] |
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