HAL Pilot
Well Known Member
I have a QB Fuse that comes with the control column horizontal assembly preinstalled and conveniently Preset to binding. I am now at that part of the build and decided to investigate a little deeper as I was not understanding why the thing was binding.
I attempted to loosen one lock nut first. Binding went away. I thought great all I need to do is re shim this side and life is good. Not so much. Many iterations and attempts later I decided I need to investigate what exactly is behind the binding as it seems that the consensus was play around with it till its good but not actually finding the cause. I decided to stop playing around with washer sizes and dive into what was going on.
My first thought was maybe the washers were being pushed into the Bearing bracket assembly. See Figure 4 bellow. As It is impossible to see into this area with the control column assembly installed, I moved it out of the way and attached a short bolt with washers and lock nut torqued to specs. It moved easily but if I put a load on the bearing by either pushing on the bolt head or locknut in the direction the bolt was pointing then I would feel binding. the washers had very little clearance around the opening So initially I thought it might be the washers contacting the Bearing assembly bracket.
To test this hypothesis, I shaved down 4 washers by placing them on a bolt and spinning with a drill in contact with a hand file. The new narrow diameter washers were reinstalled with plenty of visible clearance. The new bolt and washer assembly also moved easily but if I put a load on the bearing by either pushing on the bolt head or locknut in the direction the bolt was pointing then I would still feel binding, so the culprit is not the bearing assembly bracket or interference with the washers.
Long story short the culprit is side load on the bearings themselves. As an example, if you place one extra larger size washer on the locknut side on each end of the control column assembly (Spot A in figure 4). Make it big enough for demonstration purposes that you have to force it between the tab and the bearing you would end up pushing each bearing outboard and causing binding in both the left and right bearings because they are both having a side load imparted.
The fix then is to have enough washers in all 4 places (inboard and outboard on both ends of the control column assembly) without being able to see gaps easily so that when the lock nut is torqued neither tab of the control column assembly is being pushed in either direction as that would impart a side load on the bearing.
The question for tomorrow is how does one do that without having to assemble torque and disassemble the part 25 times. ;-)
I will update hopefully with useful info.
I attempted to loosen one lock nut first. Binding went away. I thought great all I need to do is re shim this side and life is good. Not so much. Many iterations and attempts later I decided I need to investigate what exactly is behind the binding as it seems that the consensus was play around with it till its good but not actually finding the cause. I decided to stop playing around with washer sizes and dive into what was going on.
My first thought was maybe the washers were being pushed into the Bearing bracket assembly. See Figure 4 bellow. As It is impossible to see into this area with the control column assembly installed, I moved it out of the way and attached a short bolt with washers and lock nut torqued to specs. It moved easily but if I put a load on the bearing by either pushing on the bolt head or locknut in the direction the bolt was pointing then I would feel binding. the washers had very little clearance around the opening So initially I thought it might be the washers contacting the Bearing assembly bracket.
To test this hypothesis, I shaved down 4 washers by placing them on a bolt and spinning with a drill in contact with a hand file. The new narrow diameter washers were reinstalled with plenty of visible clearance. The new bolt and washer assembly also moved easily but if I put a load on the bearing by either pushing on the bolt head or locknut in the direction the bolt was pointing then I would still feel binding, so the culprit is not the bearing assembly bracket or interference with the washers.
Long story short the culprit is side load on the bearings themselves. As an example, if you place one extra larger size washer on the locknut side on each end of the control column assembly (Spot A in figure 4). Make it big enough for demonstration purposes that you have to force it between the tab and the bearing you would end up pushing each bearing outboard and causing binding in both the left and right bearings because they are both having a side load imparted.
The fix then is to have enough washers in all 4 places (inboard and outboard on both ends of the control column assembly) without being able to see gaps easily so that when the lock nut is torqued neither tab of the control column assembly is being pushed in either direction as that would impart a side load on the bearing.
The question for tomorrow is how does one do that without having to assemble torque and disassemble the part 25 times. ;-)
I will update hopefully with useful info.