|A K-Max flying Rotex Helicopters|
|Role||Medium lift helicopter|
|First flight||December 23, 1991|
The Kaman K-MAX (company designation K-1200) is an American helicopter with intermeshing rotors (synchropter) by Kaman Aircraft. It is optimized for external cargo load operations, and is able to lift a payload of over 6,000 pounds (2,722 kg), which is more than the helicopter's empty weight. An optionally remote controlled unmanned aerial vehicle version is being developed and is being evaluated in extended practical service in the war in Afghanistan.
In 1947 Anton Flettner, a German aero-engineer, was brought to the United States as part of Operation Paperclip. He was the developer of the two earlier synchropter designs from Germany during World War II: the Flettner Fl 265 which pioneered the synchropter layout, and the slightly later Flettner Fl 282 Kolibri ("Hummingbird"), intended for eventual production. Both designs used the principle of counter-rotating side-by-side intermeshing rotors, as the means to solve the problem of torque compensation, normally countered in single–rotor helicopters by a tail rotor, fenestron, NOTAR, or vented blower exhaust. Flettner remained in the United States and became the chief designer of the Kaman company. He started to design new helicopters, using the Flettner double rotor.
The K-1200 K-MAX "aerial truck" is the world's first helicopter specifically designed, tested, and certified for repetitive external lift operations and vertical reference flight (Kaman received IFR Certification in 1999), an important feature for external load work. Other rotorcraft used for these tasks are adapted from general-purpose helicopters, or those intended to primarily carry passengers or internal cargo. The K-MAX can lift almost twice as much as the Bell 205 using about the same engine. The aircraft's narrow, wedge-shaped profile and bulging side windows give the pilot a good view of the load looking out from either side of the aircraft.
The transmission has a reduction ratio of 24:1 in three stages, and is designed for unlimited life. The rotor blades (turning breaststroke style) are built with a wooden spar and fiberglass trailing edge sections. Wood was chosen for its damage tolerance, fatigue resistance and to take advantage of field experience and qualification data amassed from a similar spar on the HH-43 Huskie helicopter, built for the U.S. Air Force in the 1950s and 1960s. The pilot controls blade pitch with tubes running inside the mast and rotor blades to move servo flaps that pitch the blades, reducing required force and avoiding the added weight, cost and maintenance of hydraulic controls.
The K-MAX relies on two primary advantages of synchropters over conventional helicopters: The increased efficiency compared to conventional rotor-lift technology; and the synchropter's natural tendency to hover. This increases stability, especially for precision work in placing suspended loads. At the same time, the synchropter is more responsive to pilot control inputs, making it possible to easily swing a load, or to scatter seed, chemicals, or water over a larger area.
|RC version of K-MAX at Ft. Eustis|
|Autonomous K-MAX at Yuma[dead link]|
|Unmanned K-MAX at Yuma|
|K-MAX with wrecking ball|
Thirty-eight K-1200 K-MAX helicopters have been built. As of January 2015, 11 of these were not airworthy or have been written off in accidents, 5 are in Limbo at Kaman, and in March 2015 the number of operational K-MAXes was 21. The production line was shut down in 2003, but may restart if the U.S. Marine Corps orders more autonomous K-MAXs.
In February 2014, Kaman revisited the idea of resuming K-MAX production, having recently received over 20 inquiries for firefighting, logging or industry transport requirements additionally to requests for the military unmanned version. Ten firm orders may convince Kaman to produce K-MAX again. Kaman has received deposits, and if enough orders come through, deliveries could occur by 2017 at a production rate of one per 6-8 weeks. The assembly line re-started in January 2017, and the first new K-MAX is to be delivered later in 2017.
The K-MAX line has flown 300,000 hours as of 2014, and costs $1,200 per flight hour to operate.
Unmanned remote control version
Kaman had been developing the Unmanned K-MAX since 1998. In March 2007, Kaman and Lockheed Martin (Team K-MAX) signed a Strategic Relationship Agreement (SRA) to pursue U.S. DoD opportunities. An unmanned mostly autonomously flying, optionally remote controlled and optionally piloted vehicle (OPV) version, the K-MAX Unmanned Multi-Mission Helicopter was developed for hazardous missions. It can be used in combat to deliver supplies to the battlefield, as well as civilian situations involving chemical, biological, or radiological hazards. A prototype of this was shown in 2008 for potential military heavy-lift resupply use, and again in 2010. In December 2010 the Naval Air Systems Command awarded a $46 million contract to Kaman for two aircraft, and in 2011 they completed a five-day Quick Reaction Assessment.
In December 2011, an unmanned K-MAX was reported to be at work in Afghanistan. On 17 December 2011, the U. S. Marine Corps conducted the first unmanned aerial system cargo delivery in a combat zone using the unmanned K-MAX, moving about 3,500 pounds of food and supplies to troops at Combat Outpost Payne. A third unmanned K-MAX in the U.S. was tested in 2012 to deliver cargo to a small homing beacon with three-meter precision. As of February 2013, the K-MAX had delivered 2 million pounds of cargo in 600 unmanned missions over more than 700 flight hours.
On July 31, 2012, Lockheed announced a second service extension for the K-MAX in Afghanistan for the Marines, then on 18 March 2013 the Marine Corps extended its use of the unmanned K-MAX helicopters indefinitely, keeping the two aircraft in use "until otherwise directed". At the time of the announcement, they had flown over 1,000 missions and hauled over three million pounds of supplies. Assessments for their use after deployment are being studied. The unmanned K-MAX has won awards from Popular Science and Aviation Week & Space Technology, and was nominated for the 2012 Collier Trophy.
On June 5, 2013, one of the unmanned K-MAX helicopters crashed in Afghanistan while resupplying Marines. No injuries occurred and the crash was investigated. Pilot error was ruled out, as the aircraft was flying autonomously to a predetermined point. The crash happened during the final stages of cargo delivery. Operational flights of the remaining unmanned K-MAX were suspended following the crash, with the Navy saying it could resume flying by late August. Swing load was seen as the prime cause. The investigation determined that the crash was not caused by mechanical problems, but by unexpected tailwinds. As the helicopter was making the delivery, it experienced tailwinds instead of headwinds, causing it to begin oscillating. Operators employed a weathervane effect to try and regain control, but its 2,000 lb load began to swing, which exacerbated the effect and caused it to contact the ground. The crash report determined that it could have been prevented if pilots intervened earlier and mission planned received updated weather reports; diverging conditions and insufficient programming meant it could not recover on its own and required human intervention.
At the 2013 Paris Air Show, Kaman promoted the unmanned K-MAX to foreign buyers. Several countries have reportedly expressed interest in the system. The K-MAX supporting Marines in Afghanistan was planned to remain in use there until at least August 2014. The Marine Corps is looking into acquiring the unmanned K-MAX as a program of record, and the U.S. Army is also looking into it to determine cost-effectiveness. In theater, the aircraft performed most missions at night and successfully lifted loads of up to 4,500 lb (2,000 kg). Hook-ups of equipment were performed in concert with individuals on the ground, but Lockheed is looking into performing this action automatically through a device mounted atop the package that the helicopter can hook up to by itself; this feature was demonstrated in 2013. Other features are being examined, including the ability to be automatically re-routed in flight, and to fly in formation with other aircraft. The unmanned K-MAX was successfully able to deliver 30,000 lb (13,600 kg) of cargo were in one day over the course of six missions (average 5,000 lb (2,270 kg) transported cargo per mission). Lockheed and Kaman have discussed the purchasing of 16 helicopters with the Navy and Marine Corps for a baseline start to a program.
The unmanned K-MAX is competing with the Boeing H-6U Little Bird for the Marine Corps unmanned lift/ISR capability. In April 2014, Marines at Quantico announced they successfully landed an unmanned K-MAX, as well as a Little Bird, autonomously using an iPad-like mini-tablet. The helicopters were equipped with Autonomous Aerial Cargo/Utility System (AACUS) technology, which combines advanced algorithms with LIDAR and electro-optical/infrared sensors to enable a user to select a point to land the helicopter at an unprepared landing site. The Office of Naval Research selected Aurora Flight Sciences and the Unmanned Little Bird to complete development of the prototype AACUS system, but Lockheed is continuing to promote the K-MAX and develop autonomous cargo delivery systems.
Both unmanned K-MAX helicopters in use by the Marine Corps returned to the U.S. in May 2014, when the Corps determined that they were no longer needed to support missions in Afghanistan. After deploying in December 2011, originally planned for six months, they stayed for almost three years and lifted 2,250 tons of cargo. The aircraft were sent to Lockheed's Owego facility in New York, while the service contemplated the possibility of turning the unmanned K-MAX from a proof-of-concept project into a program of record. Formal requirements for unmanned aerial cargo delivery are being written to address expected future threats, including electronic attack, cyber warfare, and effective hostile fire; these were avoided in Afghanistan quickly and cheaply by flying at night at high altitudes against an enemy with no signal degradation capabilities. Officials assessed the K-MAX helicopter that crashed and planned to repair it in 2015. The helicopters, ground control stations, and additional equipment are stored at Lockheed's facility in Owego. The two unmanned K-MAXs, designated CQ-24A, were to be moved to a Marine Corps base in Arizona by the end of September 2015 to develop tactics and operations concepts to inform an official program of record for a cargo UAV.
Lockheed Martin demonstrated a fire fighting version in November 2014, and again in October 2015, when it delivered over 24,000 pounds (11,000 kg) water in one hour. A casualty evacuation exercise was performed in March 2015 in coordination with an unmanned ground vehicle and mission planning system. A medic launched the UGV to evaluate the casualty, used a tablet to call in and automatically land the K-MAX, then strapped a mannequin to a seat aboard the helicopter.
- Skywork Helicopters Ltd.
- Rotex Helicopter AG
- Central Copters, Inc.
- Helicopter Express
- HeliQwest International
- Swanson Group Aviation
- Timberline Helicopters, Inc.
- United States Marine Corps
- Crew: one
- Capacity: 6,000 lb (2,700 kg) external load
- Length: 51 ft 10 in (15.8 m)
- Rotor diameter: 48 ft 3 in (14.71 m)
- Height: 13 ft 7 in (4.14 m)
- Empty weight: 5,145 lb (2,334 kg)
- Useful load: 6,855 lb (3,109 kg)
- Max. takeoff weight: 12,000 lb (5,400 kg)
- Powerplant: 1 × Honeywell T53-17 turboshaft, 1,341 kW (1,800 shp), flat rated to 1,118 kW (1,500 shp) for take-off / 1,350 shp in flight)
- Maximum speed: 100 knots (185 km/h, 115 mph)
- Cruise speed: 80 knots (148 km/h, 92 mph)
- Range: 267 nmi (495 km, 307 miles)
- Service ceiling: 15,000 feet (4,600 m)
- Fuel consumption: 85 gallons/hour
- Related development
- Aircraft of comparable role, configuration and era
- The Kaman K-MAX Production list by Markus Herzig
- Kaman restarts K-Max production on new commercial orders Flightglobal
- Kaman Resumes Commercial K-MAX Helicopter Production Helis
- Boyne, Walter J. (2011). How the Helicopter Changed Modern Warfare. Pelican Publishing. p. 45. ISBN 1-58980-700-6.
- "Anton Flettner"; Hubschraubermuseum Bückeburg
- "Twin Turborotor Helicopter". Popular Mechanics, August 1954, p. 139.
- Head, Elan (9 March 2015). "Going Solo". Vertical Magazine. Archived from the original on March 16, 2015. Retrieved 17 March 2015.
- Gray, Peter (26 June 1996). "Long - Lining". Flightglobal. Reed Business Information. Archived from the original on June 21, 2015. Retrieved 21 June 2015.
- 'K-MAX Intermeshing Rotor Drive System' 53rd Annual Forum Proc., AHH, 1997.
- 'Composites take off ... in some civil helicopters.' 1 March 2005. Retrieved: 26 June 2011.
- Chandler, Jay. "Advanced rotor designs break conventional helicopter speed restrictions (p. 2) Archived July 18, 2013, at the Wayback Machine." . ProPilotMag, September 2012. Accessed: 10 May 2014. Archive 2
- Karman III, John R. (18 August 2008). "Demolition precedes new construction for Ursuline schools".
- The Kaman K-MAX Current Status SwissHeli.com by Markus Herzig
- http://www.sust.admin.ch/pdfs/AV-berichte/[permanent dead link]/2142_e.pdf
- Padfield, R. Randall (March 2012). "Civil Tiltrotor and K-Max Aerial Truck Back in the Saddle?" (PDF). AINonline.com. Retrieved 31 March 2012.
- Kaman Aerospace Soliciting Interest in New K-MAX® Production Businesswire
- Heli-Expo 2014: Kaman looks to restart K-MAX production Shephardmedia
- Head, Elan. "Production potential" p. 44 Vertical Magazine, April/May 2014. Accessed: 8 July 2014.
- Head, Elan (15 March 2015). "Kaman still aiming to restart K-MAX production". Vertical Magazine. Retrieved 17 March 2015.
- "A shut and open case" RotorHub, August/September 2015 - Volume 9, Number 4
- Trimble, Stephen (17 January 2017). "Kaman inducts first K-Max into re-opened assembly plant". Flightglobal.com. Retrieved 18 January 2017.
- Kaman Aerospace
- Lockheed Martin K-MAX
- "Lockheed Martin And Kaman Aerospace Demonstrate Unmanned Supply Helicopter To U.S. Army". Retrieved 13 August 2009.
- "Team K-MAX demonstrates successful unmanned Helicopter Cargo resupply to U.S. Marine Corps", Lockheed Martin press release, 8 February 2010. Retrieved 14 March 2010.
- "Lockheed Martin awarded $45.8 million for unmanned KMAX" Defense Update, 6 December 2010. Accessed: 11 December 2010.
- "Lockheed Martin/Kaman K-MAX Completes US Navy Unmanned Cargo Assessment", 8 September 2011. Accessed: 9 September 2011.
- John Roach. "Robotic helicopters at work in Afghanistan". Future of Technology, MSNBC. Retrieved 22 December 2011.
- "Unmanned helicopter makes first delivery for Marines in Afghanistan". USMC. Retrieved 28 December 2011.
- "Beacon improves UAV’s cargo-delivery accuracy" Marine Corps Times, 8 July 2012. Retrieved: 9 July 2012.
- McLeary, Paul. "K-MAX Chugging Along in Afghanistan" Aviation Week, 3 February 2012. Accessed: 4 February 2012.
- U.S. Marine Corps to Keep K-MAX Unmanned Cargo Re-Supply Helicopter in Theater for Second Deployment Extension - Lockheed press release, July 31, 2012
- US Marines extend K-MAX unmanned helicopter's use in Afghanistan - Reuters.com, 18 March 2013
- "Unmanned K-MAX Wins Top Innovation Honors, USMC Praise". HeliHub. 9 January 2013. Retrieved 26 February 2013.
- "Unmanned K-MAX is nominee for Collier Trophy". HeliHub. 11 February 2013. Retrieved 26 February 2013.
- Unmanned Marine helo crashes in Afghanistan - Militarytimes.com, 13 June 2013
- US Navy set to resume K-MAX flights - Flightglobal.com, 14 August 2013
- Marines Work to Extend K-MAX in Afghanistan Through 2014 - Defensetech.org, 25 September 2013
- Tailwinds caused K-Max crash in Afghanistan - Strategicdefenseintelligence.com, 11 August 2014
- K-MAX looks to lift overseas sales - Flightglobal.com, 18 June 2013
- Stephen Trimble. "Lockheed tests K-MAX cargo enhancement" - Flightglobal.com, 18 November 2013. Accessed: 18 November 2013.
- Lockheed seeks more autonomy for unmanned K-MAX - Flightglobal.com, 11 September 2013
- USMC Unmanned Lift Competition Taking Shape - Defensenews.com, 25 September 2013
- Marines Fly Helicopters With Mini-Tablet - DoDBuzz.com, 5 April 2014
- Aurora beats Lockheed bid to develop iPad-based UAS controller - Flightglobal.com, 6 May 2014
- K-MAX RoboCopter Comes Home To Uncertain Future - Breakingdefense.com, 24 July 2014
- K-MAX returns from Afghan deployment - Flightglobal.com, 25 July 2014
- K-MAX cargo drone home from Afghanistan, headed to storage - Militarytimes.com, 2 August 2014
- U.S. Marines take next step toward cargo UAS acquisition - Flightglobal.com, 4 August 2015
- "Archived copy". Archived from the original on October 16, 2015. Retrieved 2015-10-15.
- K-Max carries out US federal government firefighting tests Flightglobal
- "Neya Systems Awarded Phase III SBIR to Demonstrate VTOL UAV Control". Neya Systems, 4 April 2014.
- Lockheed Tests Casualty Evacuation Mission with K-MAX Drone - Nationaldefensemagazine.org, 1 May 2015
- "colombian army aviation". helis.com. Retrieved 5 January 2013.
- "HELOG". helis.com. Retrieved 5 January 2013.
- "Skywork Helicopters". skyworkhelicopters.com. Retrieved 6 January 2014.
- EC725 "Peruvian police anti-drug order boosts K-MAX, p. 21" Check
|url=value (help). flightglobal.com. 29 January 2001. Retrieved 27 October 2014.
- Markus Herzig. "Swiss Helicopters - Current Fleetlist". Swissheli.com. Retrieved 18 June 2012.
- "Central Copters Inc.". Retrieved 7 July 2013.
- "Heliqwest Fleet". heliqwest.com. Retrieved 10 August 2013.
- "Swanson group aviation". DNA Web Agency. Retrieved 5 January 2013.
- "Timberline Helicopters". Retrieved 5 January 2013.
- "U.S. Marine Corp K-MAX". helis.com. Retrieved 5 January 2013.
- "K-MAX Performance and Specs". Kaman Aircraft. Retrieved October 2, 2012.
- The Kaman K-MAX Specifications SwissHeli.com by Markus Herzig
- Kaman K-1200 "K-MAX"
- "Kaman K–1200 FAA Approved Rotorcraft Flight Manual", p. 1–4. Kaman, February 17, 2004. Retrieved: October 2, 2012.
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