{{Short description|Proposed heavy-lift helicopter}} {{Infobox aircraft | name = S-73 HLH | logo = | logo_size = | image = | alt = | caption = | long_caption = | other_names = | aircraft_type = Heavy-lift cargo helicopter | aim = | outcome = | related = | national_origin = United States | manufacturer = Sikorsky Aircraft | design_group = | designer = | builder = | issuer = | status = | owners = | primary_user = | more_users = | service = | major_applications = | proposals = | prototypes = | number_built = | construction_number = | civil_registration = | military_serial = | radio_code = | requirement = | aircraft_carried = | flights = | total_hours = | total_distance = | construction_date = | introduction = | retired = | first_flight = | initiated = | in_service = | last_flight = | expected = | developed_from = CH-54 Tarhe | variants = | developed_into = | preservation = | fate = | predecessors = | successors = | concluded = }}
The '''Sikorsky S-73'''<ref>[https://www.globalsecurity.org/military/systems/aircraft/h-62.htm XCH-62 Heavy Lift Helicopter (HLH)]</ref> was a proposed aircraft design to meet the United States Army requirement in 1970 for a Heavy Lift Helicopter (HLH) capable of carrying {{cvt|45000|lb|kg t}}, a lifting capacity more than twice that of Sikorsky's most powerful helicopter at that time.
The Sikorsky's S-73 design was an enlarged version of the successful CH-54/S-64 with a simplified and improved single main rotor powered by three General Electric TF34-58 turboshaft engines rated at a combined {{convert|21,000|hp|kW|0|abbr=on}}. A crew of five would operate the aircraft from the forward cockpit with pushbuttons replacing the traditional cyclic stick and collective lever. Behind the cockpit an aft cabin provided capacity for 12 combat troops.<ref name=sik>{{cite web |url=http://www.sikorskyarchives.com/HLH%20Heavy%20Lift%20Helicopter.php|title=Heavy Lift Helicopter, HLH|author=Art Linden|date=June 2013|website=www.sikorskyarchives.com|publisher=Sikorsky Archives|access-date=21 May 2017}}</ref><ref name=arc>{{cite book |last=McKenna |first=John |title=Skycrane: Igor Sikorsky's Last Vision|year= 2010|publisher=AIAA |isbn= 978-1600867569|page=106}}</ref>
Sikorsky submitted their design in February 1971, then in May the Army declared the Boeing Vertol XCH-62 winner of the contract, ending the Sikorsky S-73 program.<ref name="sik"/>
==Specifications== {{Aircraft specs |ref=Sikorsky Archives<ref name=sik/> |prime units?=imp <!-- General characteristics --> |genhide=
|crew=five |capacity=12 combat troops or {{convert|45,000|lb|abbr=on}} max payload |length m=33.54 |height m= |height ft=31 |height in= |height note= |empty weight lb=59,000 |max takeoff weight kg=53,524 |fuel capacity= |more general= <!-- Powerplant --> |eng1 number=3 |eng1 name=General Electric TF34-58 |eng1 type=turboshaft |eng1 shp=7,000
|rot number=1 |rot dia m=37.8 |rot area sqm=<!-- helicopters -->260.2 |rot area note=4-bladed composite construction <!-- Performance --> |perfhide=yes
|max speed kmh= |cruise speed kmh= |cruise speed mph= |cruise speed kts= |cruise speed note= |never exceed speed kmh= |never exceed speed mph= |never exceed speed kts= |never exceed speed note= |range miles= |combat range km= |combat range miles= |combat range nmi= |combat range note= |ferry range km= |ferry range miles= |ferry range nmi= |ferry range note= |endurance=<!-- if range unknown --> |ceiling ft= |g limits=<!-- aerobatic --> |roll rate=<!-- aerobatic --> |climb rate ms= |time to altitude= |disk loading kg/m2= |disk loading lb/sqft= |disk loading note= |fuel consumption kg/km= |fuel consumption lb/mi= |power/mass= |thrust/weight=
|more performance= }}
==See also== {{aircontent |related= * Sikorsky CH-54 Tarhe * Sikorsky S-64 Skycrane |similar aircraft= * Boeing Vertol XCH-62 * Mil Mi-10 |lists= * List of helicopters |see also= * Aerial crane }}
==References== {{Reflist}}
{{Sikorsky Aircraft}}
Category:Sikorsky aircraft Category:Three-turbine helicopters Category:United States military helicopters