So, I had a brainstorming session with Joni (Lillebe) last night and we came up with an interesting idea that avoids springs and such altogether.How about this?http://tigert.gimp.org/aviation/vatsim/coc...t-centering.jpgIt needs a bit of explanation: The yoke is the usual "pole" model, then it has a stiff "pushrod" horizontally (like PoRrEkE's Fokker 50 yokes have for the dual-action movement - similar pushrod that goes under the panel)Under the panel there is a large pendulum-like thing - at the bottom of the panel (my panel started as a desktop thingy, so it has a "floor" of 14mm plywood) there is a heavy-duty metal hinge that is connected to a block of wood or metal that hangs downwards. On the bottom edge there is a *heavy* weight. Like a fitness handweight or a gallon bottle filled with sand or something. This goes between the rudder pedals so it shouldnt be on the way (or just move it further front)The yoke pole and the pendulum are connected with the pushrod, so that the pushrod connects to quite high up in the vertical block, thus giving a nice force thanks to the longer arm that pulls the weight straight down.Then one might want a car suspension or something for really heavy jets feel.But in any case, I think this might work. Must build a prototype to see.The trick here (that might also work for Roger's stalled motor thing) is to put the pushrod on the top part of the pole yoke. I know it sucks for the looks, since you get the pushrod there, but it doesnt do a jack of problem in practice since it will be out of sight even, behind the yoke pole. The gain is you need a lot less force to center the yoke pole compared to if you had the centering springs or pushrod on the bottom.Comments? Ideas?Also, does anyone have good ideas how to do the aileron centering? I wish to get away from the "duct tape" department and into some more durable construction that doesnt need to be fixed every other week :)//Tuomas

Hi TuomasI like the idea but suspect some damping mechanism would be needed to stop the pendulum swinging effect. Also would be better to have the pushrod under the floor.... but then a heavier weight might be required. Re: ailerons the same technique could be used with the weight linked with cogs and chains to a central weight instead of a pushrod.Its good to see new ideas...thanks

>Hi Tuomas>I like the idea but suspect some damping mechanism would be>needed to stop the pendulum swinging effect.Yes, I intend to put a dampener 45 degrees between either the pendulum and the panel "floor" or between the simulator base and the yoke pole. I have small washing machine dampeners that are not very heavy - though even a car dampener is not that heavy compared to a real level-D sim, I have seen a Md-80 and B757 and Md-11 sims and those things are _heavy_.. you dont wonder anymore why those guys fly with both hands on the cockpit videos :)For my light twin the washing machine dampener would be enough. Also it is easy to adjust the dampening force by moving the attachment point closer to the hinge of the yoke pole = less force.>Also would be>better to have the pushrod under the floor.... but then a>heavier weight might be required.A LOT Heavier weight, plus a lot more stress to the structure. But yeah.>Re: ailerons the same>technique could be used with the weight linked with cogs and>chains to a central weight instead of a pushrod.>Its good to see new ideas...thanksCogs and chains sound complex - what I like in this idea for elevator axis is that it is very very simple and thus should be durable and smooth.But the weight might well work there too indeed. Then again, ailerons do not really need the centering force all that much, it is much more critical for elevator. Thanks.As a bonus it doesnt sound too hard to make a trim-adjusted centering point by moving the pendulum attachment hinge back and forth..//Tuomas

TuomasOne question..... what is the yoke pole height and the for/aft travel of pole at the yoke? I'm curious as to how much centering force would/could be generated and how non-linear the force would be over the yoke pole "travel" range.Gus B

It's not been built yet. Whatever sitting on the car seat makes for a good yoke height. It'll be pivoting on the base floor of the sim.But it sounds like a reasonable thing to try out, probably over the weekend. I bought some more hinges already :)//Tuomas

You have a very interesting and creative idea!In addition to moving the hinge position to change the apparent trim zero force point, you could use a lead screw to raise and lower the weight to scale the centering force.Mikewww.mikesflightdeck.com

>You have a very interesting and creative idea!>>In addition to moving the hinge position to change the>apparent trim zero force point, you could use a lead screw to>raise and lower the weight to scale the centering force.>>Mike>www.mikesflightdeck.comYeah, I know. But that is beyond my current scope - although it would be entirely possible to do that.It definitely requires a dampener though, otherwise your flying will be a bit um.. .. oscillating.. :-)//Tuomas

Okay, testing begins here :)http://tigert.gimp.org/aviation/vatsim/coc...le-attached.jpgI just need a more sturdy hinge for the bottom of the pole, this one I am using is flexing a bit too much. And I got to add the suspension next.http://tigert.gimp.org/aviation/vatsim/coc.../yoke-hinge.jpgBut it's a start :)//Tuomas

I have a follow-on idea from this one, too !One of the drawbacks with the elevator trim adjustment in most sims is that it doesn't move the position of the yoke itself. In a real plane, you pull the yoke back to the required position, then adjust the trim until the yoke stays put with no force. In a sim, as you apply trim, you let the yoke move back to the centered position. With this idea of yours, you could mount the hinge for the weight onto a worm gear driven from the trim wheel, and thus move the physical position of the yoke's neutral point instead of neutral always being vertical.Richard

Yes, this is part of the original idea. The possibility to "trim off control forces" has been one of my requirements from the beginning - my yoke must be able to do it. I just left that part out the sketch for clarity so the centering idea itself was easier to understand. It's definitely something I am going to do. The weight will be mounted on a rail (designed for kitchen drawers, those suit the task nicely) and I just need to figure out a way to connect the trim wheel to this.. Car windshield wiper motors have an "angle gear" that turns the rotation 90 degrees with a reduction gearing, I could try to mount that into the trim wheel with an axle I guess. Requires pondering in any case, since I need to put the trim wheel ideally next to my seat to get a sensible cockpit ergonomy, the panel is full of throttle levers already :) One possibility might be those flexible axles you can get for drills, but I am wondering if those actually can be used in reverse direction.. Any ideas for how to solve the "transfer the rotation from the trim wheel next to the seat into the hinge thingy under the panel"?//Tuomas

TuomasAny reason the pole's base has to mount with a hinge?? What about the possibility of having the yoke post pivot on a shaft with bushings and/or bearings for a more "solid" feel??Gus

Hi,While working on my tests regarding "electro-magnetic control loading" which undoubtetly is the future of the simulation, controal loading and motion control, I got interesting result using that simple and cheap Neodynium permanent magnets.The Magnets are opposed (blu) North against North and so on, and so the created magnetic field acts like a spring on both side. The feeling is amazing, incomparable to gas springs or hydraulic dampers. It works also with the same design on the pitch axis.I dont know how it will stay stable in the future, no idea about it, but I will anyway use a magnetic field created by current and regulated by a servo controller. There is one weak point. If you use CRT monitors close to your yoke, for the instruments. With my TFT I had no incidence. Anyway, you can make the test.Rogerhttp://forums.avsim.net/user_files/99429.jpgBlu= MagnetsGreen= Magnetic field

>Tuomas>>Any reason the pole's base has to mount with a hinge?? What>about the possibility of having the yoke post pivot on a shaft>with bushings and/or bearings for a more "solid" feel??Simplicity. I have limited tools available. But I probably will have to use inline skate bearings or something to make it solid enough, unless I find good hinges without slack. Those things are not very precision-engineered thouhg. I have a bunch of those bearings around though, and they suit this well. Hinges are just simple - I am using them in the pedals with success - plus hinges are very easy to attach and there are no large kludges of structure needed, just a few screws, the construction stays very flat and nice, hides under carpet etc easily once I get into doing the finishing work of the materials.//Tuomas

Everything you would need could be found at this site http://www.mcmaster.com/

Hi Roger,I too have been looking into using magnetic actuators for control loading. It was, in fact, the low cost of neodymium magnetic that caused me to pursue the approach.The "magic" relationship is: a one tesla field acting on one meter of wire carrying one amp will impart one newton of force.An amp is a reasonable quantity, larger currents are easily controlled. A meter is likewise managable as it can be wound up, and many, many meters of wire can be used. A newton is 0.225 pounds force (for the benefit of our non-metric readers). One tesla, however, is quite an handful. It's equal to 10,000 gauss. At tesla-level strengths one has to be careful of saturating magnetic materials. Magnets with large pole faces and high strengths can grab magnetic materials and seriously damage any fingers that happen to get in the way.Building a magnetic actuator for a columm mounted yoke is possible, but large, if one wants to deliver relatively large forces (say, around 40 pounds) to the yoke that have significant range of motion.Turns out that there are commerical units called magnetic linear actuators that can be used in this application. I looked briefly at them, and actually saw one on Ebay. I have several other projects going right now, and have put this project on hold. Hopefully some of this information may be of help to you.Mikewww.mikesflightdeck.com