Dave Jackson's points, in turn:
>>1/ The Huskie has a 23.5' radius and a 3.7' stagger. Its combined disk area is exactly 10% greater then the area of its individual disks. This represents a 10% improvement over a comparable coaxial or 4-bladed single rotor disk.
NL- True enough, but it also shows 90% commonality with a co-axial, clearly within the accuracy of our "PPRUNE Engineering" According to the data I looked at today (This web site makes me work on Sunday!!) the negative effects get large at 50% overlap, let alone 90%. While it would be better than a straight forward coaxial, the diffecence would not be thundering.
>>>2/ The tip path of the upper blade when at 90-degree azimuth is 9'-8" above the plane of the lower blade. This is a much greater gap then a coaxial has and therefor the convergence of the upper rotor's downwash will put even more of the lower retreating blade in free air.
NL- This takes the extreme of course, but the rotors have zero clearance at the hub, so the average is probably half that, or perhaps 5 feet, which is about what a typical coaxial uses as its separation. No points scored here, Dave, I think.
>>>3/ The outer portion of the retreating blade imparts the greatest (blade element) lift and this is the portion of the blade that is operating in free air.
NL - Sounds plausable, I wonder if there is any data to describe
>>>If the payload of a helicopter is 50% of its gross weight, then the above represents at the very least a 20% increase in payload.
NL- The data gets muddy here, mostly because there is little to quantify the one possible advantage from above. The H-43 is so very hover efficient because of its extremely low disk loading, where the 48 foot rotor(S) lift about 9000 pounds of aircraft (5 pounds per square foot for 1 rotor, 2.5 pounds for both, the reality is somewhere in between). A Bell 412 is 6.5 PSF so it would use 40% more power just because of the disk loading, not the planform.