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Sikorsky–Boeing SB-1 Defiant

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The Sikorsky–Boeing SB-1 Defiant (stylized as "SB>1"; company designation S-100) was the Sikorsky Aircraft and Boeing entry for the United States Army's Future Long-Range Assault Aircraft program to replace the Sikorsky UH-60 Black Hawk. It is a compound helicopter with rigid coaxial rotors, powered by two Honeywell T55 turboshaft engines; it first flew on 21 March 2019.

SB-1 Defiant
Flight demonstration in February 2020
Role Compound helicopter
National origin United States
Manufacturer Sikorsky Aircraft / Boeing
First flight 21 March 2019[1]
Status Canceled

In December 2022, the U.S. Army selected the rival Bell V-280 Valor as the winner of the Future Long-Range Assault Aircraft program.[2]

Development

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Sikorsky Aircraft and Boeing are jointly producing a medium-lift-sized demonstrator they named SB>1 Defiant[3][4] (also widely known as "SB-1")[5][6] for phase one of the program. Originally planned to fly in late 2017, its first flight was delayed in April 2017 to early 2018.[7] Once flight testing begins, the aircraft will be evaluated by the Army for further development.[8][9] Sikorsky is leading the development of phase one with an aircraft based on their previous Sikorsky X2 design.[10]

Boeing plans to lead phase two, which is the mission systems demonstrator phase.[11] The Boeing-Sikorsky team is seen to have an advantage with their large industrial base that may result in wider support from Congress. Their transport helicopters are the most-used in the Army currently.[12]

Up to 2013, Sikorsky and partners have spent $250 million on X2 and Raider.[6] The team and aircraft will be separate from the S-97 Raider.[10] The team feels confident in the SB-1 Defiant and is paying for more than half of its design costs. The last project the companies teamed up for was the RAH-66 Comanche, which started in the 1980s and cost $7 billion before being cancelled in 2004. They say that factors outside their control, like budget cuts, "requirement creep", and a long development period caused problems with the Comanche and not team dysfunctionality. Under the Comanche program, each company built different parts of the aircraft. For JMR, employees from both companies will work together. The team named the suppliers in 2015.[13] Swift Engineering Inc. supports the program with a major portion of the airframe structure designed and manufactured at the company's facility in San Clemente, California by an integrated team of Swift and Boeing employees.[14]

The timeline for the first flight has slipped several times. Originally scheduled for 2017, delays arose due to a requirement to implement automated fiber placement blade manufacture at the request of the U.S. Army.[15] Further delays resulted in the first flight slipping past summer 2018.[16] Dynamic systems such as turboshafts, transmission, and rotors were scheduled to be tested at West Palm Beach, Florida, by the end of October 2018, before ground runs in November, then first flight to reach 200 kn (370 km/h) within six months.[15]

The first prototype was unveiled in December 2018, and the first flight was pushed to early 2019.[17] Ground runs began in January 2019; 15 hours of ground tests were needed before the first flight.[18]

The first flight took place on 21 March 2019 at Sikorsky West Palm Beach site in Florida.[1] In the summer of 2019, flights were suspended to address a bearing issue with the main rotor. Flight testing resumed on 24 September 2019.[19] The aircraft reached a speed of 211 knots during level flight in October 2020.[20] By December 2020, the demonstrator had logged 26 flight hours in 31 flights over the 21 months since first flight.[21] By October 2021, the demonstrator reached a top speed of 247 knots in level flight.[22]

Defiant X variant

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In January 2021, Sikorsky-Boeing announced the Defiant X variant, specifically designed for the Future Long-Range Assault Aircraft program.[23] In February 2022, Sikorsky-Boeing picked Honeywell's new HTS7500 engine, a derivative of the Honeywell T55 engine that powered the SB-1 demonstrator, as the powerplant.[24] In March 2022, Sikorsky-Boeing has selected Collins Aerospace to provide all three seating platforms and its Perigon as flight control computer.[25]

On 5 December 2022, the U.S. Army selected the rival Bell V-280 Valor as the winner of the Future Long-Range Assault Aircraft program.[2][26]

Design

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Sikorsky and Boeing state the design is to have a cruise speed of 250 kn (460 km/h), but less range due to using the "old" T55 engine. A new engine, the Future Affordable Turbine Engine (FATE), is to meet the radius requirement of 229 nmi (264 mi; 424 km).[27][5] Compared to conventional helicopters, the counter-rotating coaxial main rotors and pusher propeller offer a 185-knot (213 mph; 343 km/h) speed increase, a 60% combat radius extension, and 50% better performance in high-hot hover operations.

Sikorsky has said that the X2 design is not suitable for heavy-lift size, and instead suggests the CH-53K for heavy-lift and tiltrotor for the ultra-class.[28] However, Sikorsky plans to build the 30,000-pound-class (14,000 kg) JMR-TD (with a cabin 50% larger than the Black Hawk) at full scale to remove doubts about the scalability of the X-2 technology.[4]

Sikorsky–Boeing states the SB-1 will be quick and nimble, with fast acceleration and deceleration, fast side-to-side movement, and the capability to hover with the tail up and nose down.[29] The Defiant demonstrator will be powered by the Honeywell T55, which powers the CH-47 Chinook. It will be slightly modified to better operate at slower propeller speeds, down to 85% rpm.[30]

See also

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Related development

Aircraft of comparable role, configuration, and era

References

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  1. ^ a b "Sikorsky-Boeing SB>1 DEFIANT™ Helicopter Achieves First Flight". Boeing. 21 March 2019. Archived from the original on 15 December 2023.
  2. ^ a b Weisgerber, Marcus (5 December 2022). "Army Chooses Bell V-280 to Replace Its Black Hawk Helicopters". Defense One. Archived from the original on 3 October 2023. Retrieved 5 December 2022.
  3. ^ "Sikorsky, Boeing Selected to Build Technology Demonstrator for Future Vertical Lift - SB>1 Defiant expected to fly in 2017". Sikorsky. 12 August 2014. Archived from the original on 19 July 2015.
  4. ^ a b Parker, Andrew D. (16 October 2014). "Good things come in threes: Boeing-Sikorsky to develop two larger X2 offshoots for JMR and Future Vertical Lift". Vertical Magazine. Archived from the original on 16 July 2015.
  5. ^ a b Parsons, Dan (14 October 2014). "Sikorsky, Boeing finalise design of SB-1 Defiant". FligthGlobal. Archived from the original on 18 October 2014. Retrieved 18 October 2014.
  6. ^ a b Warwick, Graham (4 November 2013). "Sikorsky Moves X2 Technology Up A Size For JMR". Aviation Week. Archived from the original on 22 June 2014.
  7. ^ Giangreco, Leigh (21 April 2017). "Defiant's first flight falls behind". FlightGlobal. Archived from the original on 27 December 2023. Retrieved 20 April 2017.
  8. ^ Majumdar, Dave (18 January 2013). "Boeing and Sikorsky team up on US Army's JMR". FlightGlobal. Archived from the original on 14 January 2024.
  9. ^ "Sikorsky, Boeing Partner for Joint Multi-Role Future Vertical Lift Requirements". PR Newswire. 18 January 2013. Archived from the original on 14 January 2024. Retrieved 28 January 2013.
  10. ^ a b Sweetman, Bill (22 October 2013). "Boeing and Sikorsky Name New Rotorcraft". Aviation Week. Archived from the original on 14 January 2024.
  11. ^ Majumdar, Dave (28 February 2013). "Sikorsky and Boeing to pitch 'X-2'-based design for US Army JMR TD effort". FlightGlobal. Archived from the original on 15 August 2022.
  12. ^ Insinna, Valerie (14 June 2013). "Boeing-Sikorsky Team Emerges as Frontrunner After EADS Quits Army Helo Competition". National Defense Magazine. Archived from the original on 9 June 2023.
  13. ^ Drwiega, Andrew (9 April 2015). "Sikorsky-Boeing Announces JMR Defiant Team". MilTechMag. Archived from the original on 12 December 2023.
  14. ^ "Swift Joins Sikorsky-Boeing Defiant Team to deliver Next Generation Vertical Lift". Swift Engineering. 30 March 2015. Archived from the original on 30 September 2023. Retrieved 2 September 2019.
  15. ^ a b Reim, Garrett (9 October 2018). "Despite delays, SB-1 Defiant on track for 2018 first flight". FlightGlobal. Archived from the original on 23 September 2023.
  16. ^ Huber, Mark (9 August 2018). "Sikorsky Defiant Moves Closer To First Flight". Aviation International News. Archived from the original on 12 December 2023.
  17. ^ Waldron, Greg (27 December 2018). "SB-1 Defiant breaks cover". FlightGlobal. Archived from the original on 17 September 2021.
  18. ^ Reim, Garrett (31 January 2019). "SB-1 Defiant starts ground run tests ahead of first flight". FlightGlobal. Archived from the original on 31 October 2023.
  19. ^ Parsons, Dan (16 October 2019). "Defiant back in the air after 'bearing creep' issue found on test bed". Vertical Magazine. Archived from the original on 13 December 2023. Retrieved 26 November 2019.
  20. ^ Judson, Jen (14 October 2020). "Watch the SB-1 Defiant coaxial demonstrator aircraft hit 230 knots". Defense News. Archived from the original on 22 August 2021.
  21. ^ Parsons, Dan (30 December 2020). "Defiant roars through flight test milestones in 2020". Vertical Magazine. Archived from the original on 15 December 2023.
  22. ^ Reim, Garrett (12 October 2021). "Sikorsky-Boeing team to squeeze a bit more speed from SB-1 Defiant". Flight Global.
  23. ^ O'Connor, Kate (26 January 2021). "Sikorsky-Boeing Team Unveils Defiant X". AVweb. Archived from the original on 15 December 2023.
  24. ^ Beinart, Matthew (10 February 2022). "Sikorsky-Boeing select new Honeywell engine to power FLRAA offering". Defense Daily. Archived from the original on 15 December 2023. Retrieved 22 February 2022.
  25. ^ Bellamy III, Woodrow (1 April 2022). "Next Generation Perigon Flight Control Computer to See First Placement in Defiant X Helicopter". Aviation Today. Archived from the original on 15 December 2023. Retrieved 16 June 2022.
  26. ^ Capaccio, Anthony; Tiron, Roxana (5 December 2022). "US Army Taps Bell Textron for Helicopter of the Future". Bloomberg.com. Archived from the original on 3 March 2023. Retrieved 5 December 2022.
  27. ^ Gourley, Scott R. (8 October 2013). "Joint Multi-Role (JMR): The Technology Demonstrator Phase Contenders". Defense Media Network. Archived from the original on 16 November 2023.
  28. ^ Majumdar, Dave (14 September 2011). "X-2 Maxes Out in Medium-Sized Role". Defense News. Archived from the original on 20 October 2013. Retrieved 28 January 2019.
  29. ^ Hemmerdinger, Jon (23 October 2013). "Sikorsky-Boeing confident SB-1 Defiant won't be the next Comanche". FlightGlobal. Archived from the original on 22 July 2014.
  30. ^ Trimble, Stephen (18 June 2014). "Sikorsky-Boeing select T55 to power SB-1 Defiant demonstrator". FlightGlobal. Archived from the original on 1 July 2014.
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