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.

Bah! What's this youngest generation coming to....acoustic stealth!

I had not realized John Dixson was a millennial!

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.

I see this repeated ad nauseum.....and it really makes absolutely no sense. If you actually look at 3-views of the RAH-66 and 360 they look almost nothing alike outside of the fenestron assembly and the fact that it has a chine.

The 360 is far closer to a Z-10+Z-19 or a Tiger in overall shape.

https://i.ibb.co/KbYdQ6z/Untitled.png

Just a bit nitpicking but your last picture shows an Agusta A-129 Mangusta, not a Tiger

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 couldn't find a decent 3D silhouette of the Tiger that matched the rest, but the AW was even closer with its slightly lower pylon

deleted for being stupid.

Not fixed shaft turbine
 

Single spool engines refers to the gas producer section of the engine, and does not effect the power turbine section. Still a free turbine engine....

https://www.geaviation.com/sites/def...dual-spool.pdf

You are correct. The dual spool P&W/Honeywell engine would allow for better performance at a reduced power turbine speed.

Since all of the FARA competitors are using the new GE ITE engine, are you saying none of them will use variable rotor rpm to avoid advancing blade Mach effects?

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.