I run an inch and a half knife {quick-cut} style knife on my NH 30ft. header with an AWS air reel. I have personnally cut 50 bu. beans at 8.2 mph and was snipping them off right on the ground. I also have another header with a SCH cutting system and a Crary Air Reel. The 1.5 inch knife cuts alot better than the 3.0 inch system but needs to have the holddowns shimmed periodically. I designed a precision adjuster plate that bolts onto the holddown and enables one to shim an entire 30 ft. knife to 1 thousands tollerance in 20 minutes. I find a 3 inch cutting knife is the weak link in getting absolute capacity out of your combine. The AWS air reel is very simple to install and does an excellent job of saving soybeans and improving the feeding of any combine. This maker can mount the blower on the header or if it is a JD. or Case combine, direct off the main combine on the right side of the cab.