Spraying has evolved very much over the past 60 plus years, everything started as engine driven mainly because there wasn't enough power in tractors to run anything from the power take off shaft, well at least anything that required a considerable amount of power.  As tractors have progressed over the years, the need for quality equipment has consistently followed, and Air-O-Fan has lead the industry in technological advancement.  From our old BD-32 500 gallon model which had our DK turning hitch, mechanical agitation, belt driven fan/pulley system, and centrifugal pump, we developed our GB product line which was the first model in the industry to have a gear box driven fan assembly, this revolutionized how PTO driven sprayers would transmit 540 (RPM) PTO power to an axial flow fan and produce 2,600 RPM performance.  Know this type of performance comes at a cost, at the end of the day that cost is horse power.  As the tractor market has progressed, the ability to get big performance from a simple and cost effective PTO driven sprayer has only increased. 
   Air-O-Fan has led this race for many reasons, some of which can't be mentioned, but the honest truth is we use only the best quality products (we believe in quality), knowledgeable service, and we treat our customers as we would want to be treated, we specialize in air-blast sprayers and we stock an inventory of everything that we manufacture (as well as old products that are no longer in manufacturing), and our products are not assembly line, we custom build each machine to your growing needs.  If our growers have special requests 9 time out of 10 those requests are met, we listen to the guy in the field who is maintaining the equipment and we are always looking to make the equipment better.  We have added centralized grease points to the outside of the frame to make greasing more simple and easy, and on our reverse fan models the rear guarding is hinged from both sides allowing better access for cleaning and service.  Our complete product line is manufactured in-house, we build our own tanks, chassis, fan housings, steel axial flow fans, and guarding.  Our tanks are manufactured from heavy gauge 304 stainless steel and we go the extra mile to weld internally and support structurally to make our tanks out-last any other. Our fan housings are supported on their own chassis and designed to transmit harmonic vibration which prolongs the life of the product and our steel axial flow fans are custom tuned in-house to suite your growing need whether you have big horse power and want maximum performance or have small horse power and need a custom tuned fan to get the most out of what your tractor can handle. 
   It's all about horse power!  It takes big power to get big performance, if anyone tells you that they can run a dual fan PTO sprayer with a 75 PTO horse power tractor its because they are running a fan assembly that is losing air performance due to fan deflection (fan deflection is a lose of degree pitch on the fan blade as the fan attempts to compress air).  This lose of performance if often overlooked because the air leaving the fan housing is still traveling at the same speed but the air volume behind that air speed is what is lost.  This air volume is what is displacing the air out of your tree canopy and replacing it with chemical laden air, so naturally, if you can keep the performance curve of the fan constant to your peak RPM (which would be 2,600 RPM's), this will equal the maximum amount of performance that can be achieved from any given type of fan whether that fan is plastic, aluminum, or steel.