Sikorsky's Experimental Aircraft
John, I do recognize the obvious similarity between the Model 360 and RAH-66, but in particular I was referring to an aerodynamically significant wing on both the M360 and S-67. The S-67 wing was quite large and I assume could offload the main rotor in high speed flight so that the rotor could still be effective at producing horizontal force at a lower thrust level at high Mu. The M360 doesn’t look quite as significant but the renderings make it look more purposeful than simply as weapon storage and I assume rotor offload is part of how it will cruise at the claimed 185 knots. RAH-66 obviously looks similar but that’s a distinct difference.
Thanks for the info on the S-67 rotor rpm, I suspected that might be the case.
Thanks for the info on the S-67 rotor rpm, I suspected that might be the case.
Thread Starter
Was not a stealthy audible situation however.
SD, some further comment re the 67 and wings on helicopters. NASA commissioned a maneuverability test program on the S-67, to include maximum G capability, wings on and wings off. We were a bit surprised that the G advantage with wings ON was less than some aerodynamic predictions. They add extra weight, and they produce vertical drag thus reducing hover performance, thus for any new design, there are puts and takes to weigh ( no pun ) before deciding.
As for responding to the subject of acoustic stealth to SAS and IFMU,I cannot. Other than my lovely spouse accusing me ( correctly so ) of having very selective hearing,I am deaf on the subject.
As for responding to the subject of acoustic stealth to SAS and IFMU,I cannot. Other than my lovely spouse accusing me ( correctly so ) of having very selective hearing,I am deaf on the subject.
The 360 is far closer to a Z-10+Z-19 or a Tiger in overall shape.
Thread Starter
Brother Dixson got to do some very interesting flying at Sikorsky.
I am thinking he knows a thing or two about the S-67.
The lucky Sod!
Sikorsky S-67 helicopter - development history, photos, technical data
I am thinking he knows a thing or two about the S-67.
The lucky Sod!
Sikorsky S-67 helicopter - development history, photos, technical data
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Not fixed shaft turbine
Sikorsky X2 - T800 engine, free power turbine
Sikorsky Raider - T700 engine, direct drive from engine to rotor
Sikorsky/Boeing Defiant - T55 engine, free power turbine
Sikorsky Raider X - new GE single spool engine, direct drive
Conclusion - Sikorsky Raider and Raider X will never fly fast, because they lose the slowed rotor technology with a single spool engine. X2 and SB-1 have free power turbines, so the drive to the rotor is decoupled from the engine central shaft.
Sikorsky Raider - T700 engine, direct drive from engine to rotor
Sikorsky/Boeing Defiant - T55 engine, free power turbine
Sikorsky Raider X - new GE single spool engine, direct drive
Conclusion - Sikorsky Raider and Raider X will never fly fast, because they lose the slowed rotor technology with a single spool engine. X2 and SB-1 have free power turbines, so the drive to the rotor is decoupled from the engine central shaft.
https://www.geaviation.com/sites/def...dual-spool.pdf
Sikorsky X2 - T800 engine, free power turbine
Sikorsky Raider - T700 engine, direct drive from engine to rotor
Sikorsky/Boeing Defiant - T55 engine, free power turbine
Sikorsky Raider X - new GE single spool engine, direct drive
Conclusion - Sikorsky Raider and Raider X will never fly fast, because they lose the slowed rotor technology with a single spool engine. X2 and SB-1 have free power turbines, so the drive to the rotor is decoupled from the engine central shaft.
Sikorsky Raider - T700 engine, direct drive from engine to rotor
Sikorsky/Boeing Defiant - T55 engine, free power turbine
Sikorsky Raider X - new GE single spool engine, direct drive
Conclusion - Sikorsky Raider and Raider X will never fly fast, because they lose the slowed rotor technology with a single spool engine. X2 and SB-1 have free power turbines, so the drive to the rotor is decoupled from the engine central shaft.
I said I was wrong. Although the competitors engine would have been a better choice. Karem has unique speed reduction technology.
The OEM producing a Nr command as a fn of speed/alt/temperature is a relatively trivial task. The main point is having an engine whose control system produces all the engine limiting and stall-free transient response characteristics throughout the Nr range required by the rotor/aircraft. That can be anything but trivial.