Combines Shoe fan

10 years ago and can't remember all the details but we bolted a complete R62 fan into an '82 N7 housing with a minimum of hassle. Suggest you check this out as it is far better course of action to follow than to try and rebuild a N series fan, as we found out. Good luck!

the fan is a constant displacment fix vane air pump. The out put volume is changed by 'choking' off the air allowed into the fan. This is the flap or choke above the fan that travels in a 45 degree arc from closed (down) to open (up) . Both min and max are determined by screws screwed in from the sides. The out put of the discharged air is 'split' via splitter. The upper air goes under the walker front and raddle drop area and the lower duct blows up through the chaffer_seive. Hope this helps.

It is usually hard to find decent illustrations on how the Gleaner _ MF _ Case Crossflow or Through flow fans actually work. The following is a link to a paper which has some illustrations of the air flow through a CF fan. Unless you are into the theory of fans then you will find the numbers a bit daunting. http:__mab.mta.hu_~szeidl_files_5-2_5-2-GabiSwp-V5N2.pdf As Tbran says, the Gleaner fans also have a splitter in the outlet to split the exiting airflow between the chaffer _ sieves and the accelerator rolls or the walkers The narrow opening in the top of the air duct from the fan to the sieves must always remain open and not be allowed to be blocked off. Unlike a centrifugal or a propeller type fan, when blocked off by say choked sieves, a cross flow fan will just continue to pump air until it runs out of horsepower or mechanically fails and disintegrates. That opening in the top of the sieve duct is a pressure release duct for the fan air if the sieves become choked. Because the cross flow fan cannot be choked at the outlet, the adjustable board _ flow regulator across the top of the fan regulates the amount of air that is allowed to flow into the fan and therefore the air flow out of the fan.

After careful study of the basics of the parameters of the mass flow derivitives, I now understand why my mother in law is full of hot air. She has a non throttled vortex! Thanks.

So tbarn and R.O.M it looks like the vortex revolves around close to the cut off point, so there is 2 air ducts, do both get the same amount of air or dose the top one get more where it is closer to the cut off pointIJ What dose the upper air duct do that is aimed at the walker and raddle drop. It was a long time before I know there was 2 air duck on gleaners. I look at neighbor N it dose not have any plastic finger in front of upper air ducted but the M dose is that same on allIJ It did take some time to go through the cross-flow fan paper, I like the pictures. I wonder if my mother in law has that vortex going too. Thanks Dee

I really do have the greatest respect for those AC combine designers of the 1970's who came up with the Gleaner cross flow fan design. As you may have read in that paper on the cross flow fan design, there is still a lot of experimentation needed to get the critical fan housing design right. The fan housing configuration is critical to having a good fan and there is no doubt that the old AC Gleaner fan is very good. The fan and housing have remained almost unchanged since first of the Gleaner rotaries, the N series, came out in the late 1970's. That fan design had to be calculated and drawn up on paper from first design principles. No computers, no CAD programs, very little in solid crossflow fan design information and maybe if the designers were very lucky they may have had use of a 4 function calculator [ worth about $400 AUD in about 1973, now worth maybe $4. ] in the early 1970's when this design work was started. I also have wondered about the two duct set up on the AC _ Gleaner fan. I think this is why the location and accuracy of the splitter location and clearances are so critical. The splitter is located very close to where the steering vortices are located and may split the flow as it comes off the vortice. Alternatively there may even be a couple of very small and intense steering vortices located just below and above the splitter which are diverting airflow into each duct. It would be interesting to see the laser image of the airflow with this splitter in place. As you cannot just blank off a section of the air inflow region to change the amount of airflow in this crossflow fan design without changing the critical fan casing design and therefore the whole nature of the fan performance, those very smart old AC designers have used a baffle that changes the air inflow pattern without actually affecting the design performance of the fan. The inflowing air can still move around the baffle into the fan right across the fan's inflow area but the obstruction to the airflow as the baffle is changed in it's position through the fan control allows increases or decreases the amount of inflowing air without blanking the casing off and changing the whole performance of the fan. You really appreciate the genius of the AC fan designer when you look at the similar Case cross flow fan design. Case designers with all the computer design power of the 1990's at their disposal still have to change the fan speed through a variable speed belt drive to get the range of performance that they need for their sieves only. The whole Gleaner rotary design was so far ahead of everything else in so many aspects that we really do not fully appreciate that those guys who drew up and did all their calculations using little more than a drawing board and pen and paper and most important of all, their eyeballs, their brains and their field smarts were close to geniuses.

Interesting reading on a system that appears to be so simple but yet mathmatically so complex. This post brings back memories of the mid 80's when we ran across an N6 that no matter what the fan setting was unless below 5 would blow corn out of the shoe. After removing the chaffer and sieve to do some measuring of splitter we found that when Gleaner went from tie-tods holding the splitter in place to installing roll pins in each side to hold the splitter that the roll pins missed the hole. The splitter ended up having a wider distance between splitter and fan and the amount of air going to the acc. rolls was tremendous. We ended up installing a adjustable bracket on each side to adjust splitter manually so we could play with air flow. Being able to fine tune the splitter distance resulted in a well mannered shoe that was easy to set and also getting the fan setting back up to 7. It would have been interesting to know the numbers before and after the splitter issue described. Rumor has it that Gleaner is playing with this area with future machines which is good as the longer shoes seem to have affected air flow. Hyper Harvest II

So on that machine was there less air to the shoeIJ Are there tools to use to see if the air is right for the 2 ductsIJ On our M there are 5 little diverters (3 on left turned little bit left and 2 on right turned little bit right) on the bottom of duct to shoe and 4 on the N (2 on the left turned little bit to the left both closes to the side 2 on the right turn little bit right closes to the side nun in the middle),there more air need for the sides and is there still same presser in the middleIJ This is fun to lauren Thanks Dee

Interesting. The R60 we just traded this past summer may have had the same thing going on. No matter how the chaffer or sieve were set we would blow corn out the back at anything over 5. I wish I could look it over to see if it was the same as you describe. Brian

Yes, if you wanted to take the time, you could measure the entire airflow pattern right across the fan and the air pressures and velocities and therefore the volumes coming out of each duct and then calculate the HP used just by using a pitot tube and a manometer. A pitot tube or probe measures both the static and velocity pressure of the airflow. The industrial pitot tube consists of concentric tubes, the outer one of around 6 or 7 mms diam with a smaller inner tube running right to the opening at the pitot tip. The tube usually has right angle bend at least 24 diameters from the tip. This allows one to poke the tube in through a small hole on one side of the tube and face it into the airflow for measuring. This small opening of the inner tube at the pitot tip measures the velocity pressure. [ pressure caused by the speed of the airflow into which the tube is pointed. ] A ring of very small holes is drilled in the larger outer tube which is sealed off from the inner tube, about 8 tube diameters back from the tip which allows the static [ air ] pressure to be measured as it passes down between the inner and outer tube. The actual measuring equipment can be a gauge or just a simple manometer which can be made up by nailing a two legged U shaped, 40 _ 50 " high piece of clear plastic tube of about 3_8" size to a piece of wood. This tube is filled with water up to about half the height of the U tube. Depending on what is being measured, one or both ends of the tube are connected to the one or both outlet tubes of the pitot tube. Both tubes connected give velocity pressures; ie; the water levels in one leg of the U tube , the manometer, goes up and the other water level goes down. The difference between the manometer water levels in both legs is carefully measured and a set of tables will give you the speed or the velocity of the airflow where the tip of the pitot tube is located. Connect one tube to the static pressure outlet which is the outer tube with the very small holes and you measure the static pressure at that point. Doing a traverse right across the duct in a number of locations using both the static and velocity pressure readings will give you the areas of the duct where the airflow velocities are slow or reduced or fast and the static pressures which will immediately show where there are dead spots and turbulence in the duct. In some situations you don't even need the pitot tube. Where we have had doubts or suspected a dead spot around a bend in a high velocity air duct, ie; airseeders, we have just drilled 4 or so a 1_16" holes around the pipe or duct and placed one end of the plastic tube of the manometer against the small hole. Pressure pushes the water down in the manometer tube. A dead spot, ie; little or no airflow in that spot and the water levels barely change or worse a low pressure area in a pipe where there should be pressure and the water was sucked up a couple of inches the manometer tube. Good for finding out where you may get blocks when using air to shift materials ie ; airseeders. Believe me, air does some very strange things. What few people realise is that air has weight, about 1.1 kgs _ cubic meter and therefore it has inertia and will not necessarily like going around a corner or bend in a smooth manner or behave as most people assume it will. So you can get dead spots and no pressure on the inside of bends quite often as the weight of the air hangs it out on the outer radius of the bend. This also wears the outside of the bend quite rapidly when you have material moving through at velocity with the airflow. Through poor design, I have also seen a complete air flow flick every few seconds from one side to the other of a flat fan shaped air seeder distributor and leave a dead spot on the opposite side. After that long discourse, a long pitot tube can be used to measure flow patterns as they flow into or flow from a fan in any machine. We worked on fans of 18,000 CFM and 32 inches of water gauge [ 32 inches difference in the water levels in the two legs_ tubes of the manometer ] taking up to 200 hp to drive down to something not much larger than a tractor _ combine airconditioner fan. We have designed and built ducting and entire air flow systems on very successful pasture seed harvesting equipment using nothing more than the above air measuring equipment and we are only your average farmers. On the deflectors in the fan ducts of the Gleaners. Against the end wall of the fans there is a great deal of retardation of the air or "drag" as it is called. Hard against the end walls the air is actually stationary and it gets faster as you move further out from the end wall. The airflow may not be up to full speed until possibly 2 or 3 inches from the end walls of the fan housing. In addition the fan blades do not extend right to the end walls so the fan blades are not picking up and accelerating the air in that last couple of inches as well. Next, the high pressure air further along the fan blades tries to flow into the low pressure areas that exist around the last inch or so of each fan blade as the air bleeds over the ends of the blades. All this means that possibly up to 5 or 6 inches or possibly much further out on each end of the fan is not pushing the full amount of air so the deflectors are in there to push some of the airflow from the centre parts of the fan out to the areas at the ends of the fan where the fan is not operating at it's full capacity due to the above reasons and to give good even airflow right across the sieves.