Alternate UTTAS designs from Bell, Sikorsky and Boeing

[Pioneer]

Total speculation on my part. C-130 requirement may have been dismissed after the rotor system had to be heightened due to blade flapping on both (?) competing helicopters. With the increase in height of the rotor head, it may have not been feasible any more for them to be put into the C-130. The C-141 requirement may have gone away due to weight restrictions on the C-141 later in life and their impending retirement.

Thanks for your response yasotay, your speculation makes sense. As for the C-141, wasn't its cargo compartment the same as that of the C-130's, in terms of width and height? So your analogy about the rotor system having to be made heightened, might also have impacted on the C-141, as it did the C-130 capacity to fit it.
Also, going by the airlift configuration mock-up of the Sikorsky, it appears that the 'kneeling' capability of the landing gear of the production Blackhawk might have been negated, as a consequence.


Regards
Pioneer

 

[Aeroweanie]

The UH-60 has a removable section in its rotor mast. When removed, this allows the head to be dropped sufficiently for the helicopter to fit into a C-130.

During the PLAAF fly-off in Lhasa in 1985, Sikorsky flew in S-70C N3124B (civil UH-60A) in a L100 (civil C-130).

 

[yasotay]

The UH-60 has a removable section in its rotor mast. When removed, this allows the head to be dropped sufficiently for the helicopter to fit into a C-130.

During the PLAAF fly-off in Lhasa in 1985, Sikorsky flew in S-70C N3124B (civil UH-60A) in a L100 (civil C-130).

Thank you for that information. I think that was dropped for both the Lima and Mike versions of the platform.

 

[Pioneer]

A few snippets of information pertaining to the UTTAS RfP and the Sikorsky S-70 design [sorry if these have already been posted]:

-The key performance requirements included a vertical rate of climb of at least 450 feet per minute at a 4,000-foot altitude and at 95 degrees F temperature and a cruise speed of at least 145 knots. Maneuverability requirements included achieving a yaw rate of 15 degrees per second while flying 35 knots sideways. The useful load included a crew of three plus the 11-man rifle squad and fuel for 2.3 hours of endurance with reserves.
-The value of that cost-type contract in then-year dollars was $61.9 million and included construction of three fight aircraft, one ground test aircraft and one static test aircraft while the Boeing Vertol contract was for $91 million for essentially the same deliverable products. The actual contract expenditures were approximately 50% higher for both companies due to unplanned work to correct problems uncovered during flight-testing.
-The Sikorsky UTTAS was designed with its 4-blade tail rotor canted upwards 20 degrees to provide approximately 400 pounds of extra lift. This lift at the tail permitted the aircraft center of gravity to be placed aft of the main rotor, which allowed the nose and cockpit to be moved aft thereby shortening the fuselage length to better fit inside the C-130 cabin during air transport.
-Other configuration features [of the YUH-60] included a tail landing gear and a tail rotor placement on the starboard side that functioned as a tractor tail rotor as opposed to the conventional pusher tail rotor. The canted tractor tail rotor provided additional clearance and safety for ground personnel. A tail landing gear configuration was selected over a nose wheel arrangement to provide protection to the airframe during high flare landings. Sikorsky had used the tail landing gear design for its earlier S-58 (H-34) model that was well accepted by pilots.

(Source: https://sikorskyarchives.com/home/s...innovation-era/sikorsky-s-70-uttas-prototype/)

Regards
Pioneer

 

[Pioneer]

The UH-60 has a removable section in its rotor mast. When removed, this allows the head to be dropped sufficiently for the helicopter to fit into a C-130.

During the PLAAF fly-off in Lhasa in 1985, Sikorsky flew in S-70C N3124B (civil UH-60A) in a L100 (civil C-130).

Do you by chance have any pics of the S-70C N3124B in or being loaded/unloaded from the said Lockheed L100 Aeroweanie ?

Regards
Pioneer

 

[Aeroweanie]

The UH-60 has a removable section in its rotor mast. When removed, this allows the head to be dropped sufficiently for the helicopter to fit into a C-130.

During the PLAAF fly-off in Lhasa in 1985, Sikorsky flew in S-70C N3124B (civil UH-60A) in a L100 (civil C-130).

Do you by chance have any pics of the S-70C N3124B in or being loaded/unloaded from the said Lockheed L100 Aeroweanie ?

Regards
Pioneer

None fall to hand, but I know I've seen one somewhere. There might be one in Ray Leoni's book "Black Hawk: The Story of a World Class Helicopter".

 

[yasotay]

The ability to lower the mast was eliminated for cost considerations. Folding blades and collapsible landing gear were deemed sufficient to fit into C-17 and larger airllifters.