3D Printed Force Feedback Yoke

1st Official Post

    Hey guys

    I wanted to create dedicated thread for my little project where I can post an updates on the Yoke. I know it's not specific to Aerofly but we do love flying and all the gadgets involved right?

    Well here's the update, I changed some settings in FS Force, also showing stall buffet and enabled damping (thanks Antoine & Jan).

    Enjoy

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    Over and Out

    Jay

    • Official Post

    The stall buffet that I know from my gliders with T-tail happens when I pull elevator at high angles of attack. It feels as if the flow on the elevator starts to separate, ver fine vibrations. On a low wing aircraft like that I would expect the buffeting to occur due to flow separations from the wing hitting the elevator at high angles of attack... Just remember the stall isn't caused by low speed, it's only the angle of attack that can cause buffeting... The speed would just influence the frequency of the buffeting as far as I know.

    How much will such a yoke cost in total, given I solder and screw everything together myself. I don't have access to a 3D printer yet and don't have any old elektronics laying around... So what would it cost, roughly?

    How much force can you create on pulling/pushing and on roll axis?

    Jan

    as far as I understand aircraft physics I thought that angle of attack is very dependent on airspeed. Traveling near stall speed with little pull on the yoke/stick will cause increased angle of attack right? Anyhow as I mentioned earlier there is a ton of available settings in FS Force so you can completely change the feedback behavior.

    Regarding the cost, I did't wanna go there quite yet because during the development I spend four times as much as I needed and only handful of parts I purchased ended up being actually used.. Well to give you my rough estimate, considering you do it your self using my STL (printing) files and tutorial (that I would have to put together) and you obviously sourced your own "handle", I'm thinking somewhere around £200.

    It's really my rough estimate though..

    Forces.. tricky question I think I'm able to measure force in the Pitch axis somehow (maybe digital scale or something) but measuring torque of the Roll seems to be very tricky. Anybody has an idea how to do this without expensive equipment?

    Over and Out

    Jay

    • Official Post

    Hi Jay,

    If you put the pitch axis vertical you can attach anything you want. e.g. a bucket of water and then fill it until it's no longer pulling it up. Then measure the mass of the bucket.

    The angle of attack topic would really go beyond the scope of this thread, maybe just briefly: you put the aircrafts wing at an angle to the airflow and that deflects air molecules downwards the amount of deflection is almost proportional to the angle of attack. But at low speed you are just deflecting a few molecules and that isn't enough for you to push on.

    At some angle of attack the flow detaches a bit and the created lift reduced even if the same airspeed is maintained. Then at even greater angles of attack the lift recovers a bit but by that point the drag is so high you won't be able to maintain that attitude for long with that little engine in front.


    The airspeed comes into play if you have a certain aircraft mass that you need to lift. The greater the lift you want to create per wing area that you have the faster you have to fly when you are flying at the edge of the stall. So speed is secondary here, yes if you maintain altitude and just reduce the speed your lift decreases with the speed rapidly (airspeed is squared in the lift equation). But you could reduce the speed futher and further, then your angle of attack just would need to become greater and greater but at some point the air will not follow the curvature anymore. Tha maximum angle of attack is what causes flow separation called "stall". The amount of air molecules is not a factor for that separation. That is why the stall will happen at the same angle of attack no matter how fast you fly or how much g-s you are pulling. If you fly a parabola with 0.0g you have a wing loading of zero and your stall speed decreases to 0 as well. In the end you are flying like a rock, so you don't need wings for that zero-g parabola. But if you start to pull elevator to fly horizontally you are then increasing the angle of attack and thus deflecting air molecules and at a certain speed that will be enough to lift your aircraft.

    So for stall recovery: lower the angle of attack and then watch the speed increase. So to come back to the topic: The buffeting is caused by the flow separation which is caused by the angle of attack.

    Quote from Jet-Pack

    If you put the pitch axis vertical you can attach anything you want. e.g. a bucket of water and then fill it until it's no longer pulling it up. Then measure the mass of the bucket.

    Hi Jan

    I've got some numbers for you but I did it differently. Your proposal was good but I don't know the mass of the axis assembly (handle, shaft, gears, motors and all that's moving within the pitch stroke). Without being able to deduct this mass from the reading the results would be useless.

    Instead I took ordinary digital scale, tip it on it's side, reset the reading and then pushed it against the yoke until it overcame it's force and started moving it. The yoke was set (via FS Force) to push the pitch axis all the way out with maximum force. At this point the reading was about 1.8kg.

    With the Roll axis, I put the scale under one side of the yoke, applied max force (in FS Force) towards the scale and again slowly moved the scale up until the yoke started rotating. Here we have reading about 0.6kg.

    According to online torque calculator (using Force x Lever Arm Length formula) the torque = 0.94Nm.

    I hope it will give you some idea about the actual feel..

    Jay

    Over and Out

    Jay

    • Official Post

    Hi Jay, thanks for measuring it for me!

    So it's not super powerful yet. But I think that largely depends on the actuators that you install, right?

    I think real world forces can go up to an equivalent of 15kg or more. So far the only bigger thing I've flown is a Cessna 350 Columbia and it's elevator force was quite noticeable compared to the touring motorglider G109B or any other glider. I really had to pull and push hard on it's side stick. Roll was had quite low forces, more like I was used to anyway.

    Regards,

    Jan

    Quote from Jet-Pack

    Hi Jay,

    a bit disappointing that the page doesn't load at all when you have a javascript blocker installed... Had to enable at least three javascripts to get it to show content.

    Anyway, looking forward to seeing your projects! Don't hesitate to share it with us here as well :)

    I'm sorry man.. no idea why is't happening. Maybe the "free wix hosting" pushing too much garbage to your screen? No really, no idea, HTML is another galaxy to me:)

    Will keep you posted for sure;)

    Over and Out

    Jay

    OK responding in this thread.

    I love this project, and I love the work you did with it, looks great.

    We currently do and will have similar needs. Our needs however are only for military hardware (because what the museum is) so it's limited to helicopter (our current most pressing need) and Navy aircrafts (very likely in the future).

    We are developing VR experiences with a variety of immersive things, just like you did. Currently we are working on a mockup cockpit of a helicopter (so fake gauges, and so on, but looks real (3D print and other modeling and building methods), Oculus for display and a real control system (collective, cyclic and pedals)). We have a buttkicker, no motion, and no force feedback. That may evolve over time.

    In the future we most likely will expand to aircrafts. Of course anything (like Force feedback, motion, etc..) is under consideration, we have the competency, but it's a matter of budget (not for people, but for hardware mostly, non profit, limited funds) and strategy (what program the museum wants to develop next).

    In any case I'm laying the groundwork for the team to start to look into this. The team however is involved in many projects, all based on technology, but not all based on VR sims, it could be fixing, reverse engineering, restoring, any piece of complex equipment like radios, fire control mechanical computes, hydraulic systems, displays and electronic monitoring, etc.. or developing new technologies in any domain.

    So while I will certainly look into this and have the team look into it, I don't have current resources to dedicate specifically to this. That may change but I can't control how, when or how fast (we're all volunteers, so schedule is typically loose and slow).

    So in short:

    - Yes we're interested.

    - Yes we have the competency (mechanical, electronics, software, computers, etc..) and tons of experience (I'm talking retired aerospace, military, etc.. engineers and similar mostly, as a team) to do pretty much anything we put our mind to and is programmed to be done.

    - We will eventually very likely work on such a software and hardware (or source it), I just can't know when and how fast the development would be right now, it could be years, or soon, or never. Better immersion, motion, etc.. are all on the table. Anything that betters the experience. Again timeframe and budgets are the 2 factors that are unknown.

    - We, as a team, have a constraint of benefiting the museum, so while our work could maybe be used otherwise (for example for a yoke for a commercial plane like yours), our primary focus will be military hardware (joystick) and so on. If it is not part of our objective, I cannot make the team work on it, it then becomes a purely individual and personal desire.

    - That same team has a lot of various projects on its plate, so that again, other than time and budget, introduces a variable in terms of priority and availability

    - FS2 and its interaction is currently looked at for future projects, so we're currently doing some preliminary evaluation and groundwork, not working full steam, so to speak, and projects have not been decided yet. If and when we move forward and develop a project based on FS2, then a lot of things may be happening (but still slow probably). It will depend on many factors (like what is possible, what do we want to do, what we can do, etc..). So far very early evaluation shows a lot of potential, so that's good. I am slowly looking into the FS2 SDK to see the potential and understand its possibilities and limitations to see if it fits and what we can imagine with it (Separately, I'm personally very interested in FS2 also). We're looking at everything that is available out there however, so I cannot guarantee where we'll spend the resources ultimately. A lot of factors are at play.

    And that is the best I can offer to you. We'll look into it, I don't know what and when it will produce if anything. If it does you'll be the first to know. And If personally I do anything, it will be in this forum I'm sure, as it has been so far, my personal specialty is mechanical systems and complex dynamics (aero, thermo) more so than purely software however.

    Let's see where all this is going organically and how much we can collaborate.

    Michael

    ussiowa

    Thank you Michael, I really appreciate your detailed response to my call. You are undoubtedly one of the rare passionate people making us so proud about this amazing community (along with other great personnel of course:) (I don't need to pull the names do I?:))

    Unfortunately I'm in a little time compression right now as I need to get ready for two weeks of hollyday starting in few hours but I'll be always watching the forum no matter where I am:)

    Wish you all the best with your project mate. Hopefully we can join the forces (along with other great personnel of course:) sometimes in the future..

    Regards Jay

    Over and Out

    Jay

    ussiowa I'm making good progress with a simple to build solution for motion. Motion "cues" actually rather than full platform movement. It uses 4 fairly cheap servos off ebay and some steel plate and hinges. Just connect the plates/flaps to an existing seat with hinges and attach the servos with levers to press them up. Software is all no problem. You get heave/surge and a sense of roll/pitch.

    You may find it suitable for your needs. See https://www.xsimulator.net/community/thre…ed-part-1.10470

    Very interesting, have you thought of doing a set of rudder pedals? Do you wish to reproduce actual control loads?, a twin on one engine near the minimum control speed would need pedals to exert something like 40 Kg before trimming, sort of like standing on bicycle pedals trying to getup a steep hill.

    Well simply put, yes..

    Due to the limitations of hardware that is currently used, I would like to develop "universal" and cheap solution based on Arduino platform providing three axis of force feedback for wide range of DC motors. Something similar to what Ian from BFF has done but much cheaper and simpler.

    I'm doing intense research on this subject however such task requires highly skilled programmers and it doesn't seems like there's many of them hanging around, having nothing else to do :(

    Once we conquer this enormous challenge and have the basic platform up and running (Arduino code + PC software suite) creating different versions of hardware controls will be a breeze..

    Regards Jay

    Over and Out

    Jay

    You may want to consider different hardware, like rasberry pi or some micropython featherboards. It's a bit simpler to program I think since it's python versus C.

    I don't want to start a programming language, or a microcontroller debate, but python is a bit more approachable in syntax for non professional coders, it offers file management and math on micropython that I think arduino doesn't offer, or as simply anyway. If push comes to shove (absolutely need an arduino hardware) there is a solution to slave an arduino to a raspi and program everything in python too. I've been looking into all this, just never had the time or urgent need enough to finalize it.

    There is also "node red" on raspi that is completely simplistic to use and create stuff, one can do advanced stuff with just dragging blocks, you may want to look it up if programming is your only limitation.

    Quote from Jay 737

    Well simply put, yes..

    Due to the limitations of hardware that is currently used, I would like to develop "universal" and cheap solution based on Arduino platform providing three axis of force feedback for wide range of DC motors. Something similar to what Ian from BFF has done but much cheaper and simpler.

    I'm doing intense research on this subject however such task requires highly skilled programmers and it doesn't seems like there's many of them hanging around, having nothing else to do :(

    Once we conquer this enormous challenge and have the basic platform up and running (Arduino code + PC software suite) creating different versions of hardware controls will be a breeze..

    Regards Jay

    Could Simtools be used to position a servo according to the forces the aircraft is experiencing, and have the servo somehow add appropriate tension to the rudder pedals? Then the only programming needed is a bit of arduino parameter tuning. I have arduino code that talks to simtools and moves servos.

    Quote from ussiowa

    You may want to consider different hardware, like rasberry pi or some micropython featherboards. It's a bit simpler to program I think since it's python versus C.

    I don't want to start a programming language, or a microcontroller debate, but python is a bit more approachable in syntax for non professional coders, it offers file management and math on micropython that I think arduino doesn't offer, or as simply anyway. If push comes to shove (absolutely need an arduino hardware) there is a solution to slave an arduino to a raspi and program everything in python too. I've been looking into all this, just never had the time or urgent need enough to finalize it.

    There is also "node red" on raspi that is completely simplistic to use and create stuff, one can do advanced stuff with just dragging blocks, you may want to look it up if programming is your only limitation.

    Thanks

    Actually yes, programming is my only limitation, it's driving me crazy as I don't know where to start. I don't want to drag this project over several years and somehow become programmer along the way.. Not that I wouldn't like the subject , it's the fact that I would have to start from very basics so I can imagine getting full understanding of what I wanna do would grow very long beard on my chin. I'm talking VERY long beard..

    I was directed to one guy on ED Forum who made a script for arduino pro micro that turns it into FFB HID (as recognized by windows) . However there's another catch. With only two working axis this board uses up all the ram it has so it can't even hold bootloader. He explained that any other features like communication with management software is simply not possible.

    Well there are another two options on my list.

    1. STM32F4 Discovery - which has proven to work really well within racing sim community

    https://forum.virtualracing.org/showthread.php…back-Controller

    2. SimuCube - more commercial solution but again, developed for racing sims.

    https://granitedevices.com/simucube-simul…ack-controller/

    That brings me to Spit40's question about Simtools. All these solution were developed for different purpose from mine. I need to get much more from them than just one axis and few buttons, however it shows what these boards are capable of.

    Well lets assume that I will have to jump into the pool and start all this process on my own.

    Exactly how capable is Rasberry Pi ?

    Can you compare it to STM32F4 Discovery ?

    Is it worth it trying to modify any of the existing racing FFB solutions?

    Best regards

    Jay

    Over and Out

    Jay