Harrier Throttle Nozzle Quadrant

[engines]

I'm making a dedicated thread on a throttle nozzle quadrant build that I'm working on.  This is something that started a while ago with a pretty detailed design effort that was put on hold for two reasons: 1. my 3D printer was having issues that needed to be investigated, and 2. designing the throttle grip was quickly determined to be too difficult based on the information I had at the time.

Since then I have bought a new 3d printer and the old one has now been stripped down for parts for the quadrant.  I have also stumbled across several excellent photos from @mattjonesgr9 that were posted on a UFC build thread.  This is now enough, along with a short break in work travel madness, to allow me to hit this project hard again.  I'm hoping I can keep enough momentum to get a working prototype finished in a few weeks.

These are the original renderings of the quadrant enclosure assembly:

I did manage to print out this first grip effort, but it was so far off the mark, I didn't know where to start.  Since then I have come up with this design for the shell:

Whilst not perfect, for a solid body, it's close enough.  I've also scaled down the component by a factor of 0.9 as the printed version felt a tad too big for an ungloved hand.

This first prototype won't be made of sheet metal as originally planned, but will be assembled from 2020 extruded aluminium and 3D printed parts.  I will also be using a hall effect sensor for each of the three rotating axis instead of potentiometers.

[engines]

 

I'm pretty happy with the draft grip print, so I'm in process of eating the elephant.  The detail design work on this is was more complicated than I had anticipated.  I have split the grip into three sections, one of which is printing now and should be ready tomorrow.  I need to finish the detail on the "head" of the grip with the other switches.

While I have been working on this, to have a bit of break, I've been working on the friction mechanism.  I have mocked up the quadrant with the bearings and geometry I intend on using, but while the dimensional tolerance is good, I'm going to have to do some work to fine tune the friction.  I hope the method I use is going to be effective.  Here is a glimpse of some of the structure.  It's hard to describe what I have in mind, so I will just share more photos when I'm there.

 

[mattjonesgr9]

Looks awesome !

[engines]

Cheers, those renderings you found unlocked this for me to continue!

[engines]

 

Framework v9.avi

 

Pretty much there with the detail design now and I have all the parts I need for assembly.

Edited November 9, 2021 by engines

[engines]

[aaronwhite]

That's looking awesome! 

I wish I had these skills! I would love to make all sorts of custom HOTAS grips for my Orion throttle base. It seems like the perfect base for these things.

[engines]

Some test and assembly prints are ready.

[engines]

Custom "button matrix" PCBs for the inputs. I feel like I should have increased the trace size from default. We shall see.

[engines]

Functional testing of the input matrix is looking good so far.  I've only tested a couple of the digital inputs to verify the board and code works. I'll have to look at the analogue stuff next while I wait for the rest of the diodes to arrive.

 

 

[engines]

I'm redesigning this to make it more print and manufacturing-friendly.

 

 

Edited November 17, 2021 by engines

[mattjonesgr9]

On 11/8/2021 at 5:43 AM, engines said:

Cheers, those renderings you found unlocked this for me to continue!

Will you share the stl files ?

[engines]

If I can get them to a good enough standard, absolutely.

[Xpendable]

On 11/10/2021 at 11:35 PM, engines said:

Functional testing of the input matrix is looking good so far.  I've only tested a couple of the digital inputs to verify the board and code works. I'll have to look at the analogue stuff next while I wait for the rest of the diodes to arrive.

 

I don't understand what purpose the diodes serve in your circuit...  Can you explain?  It looks like you're just hooking them up directly to the digital I/O pins on the Arduino, and that shouldn't require the use of diodes. Assuming of course you are using the built-in pull-up resisters mode on the Arduino. 

[PhoenixRising]

I believe that it prevents "ghosting" or unwanted button presses when used in a matrix. It serves a different function than the pull-up resistors.

Sent from my moto g stylus 5G using Tapatalk

[engines]

That's exactly it.  It prevents spurious inputs when a combination of buttons are hit simultaneously.

[Xpendable]

I see. That makes sense. I usually use multiplexing chips in my designs such as the mcp23017 which makes the diodes unnecessary, although you do need resistors in that case. Of course adding a chip also increases cost and there is a bit of work in the code necessary to make it work - which I already have as I reuse it in a bunch of designs.

[engines]

A quick peak at the unit attached to my chair.

[Xpendable]

On 11/8/2021 at 10:58 PM, engines said:

 

Framework v9.avi 4.53 MB · 0 downloads

 

Pretty much there with the detail design now and I have all the parts I need for assembly.

 

It won't let me see or download this video.

[Xpendable]

By the way, this is looking really awesome.  Did you put any metal inside the yellow throttle arm for strength?  I'm guessing you did, but can't really tell from the 1 picture.  

[engines]

17 hours ago, Xpendable said:

It won't let me see or download this video.

It may have moved. I'll have a better one up at the end of the week with (hopefully) a functional friction mechanism.

15 hours ago, Xpendable said:

By the way, this is looking really awesome.  Did you put any metal inside the yellow throttle arm for strength?  I'm guessing you did, but can't really tell from the 1 picture.  

The only metal is for the M4 inserts and the screws themselves. The grip is made from PETG for better surface finish and durability, but there is internal structure that holds it all together that is using ABS for higher modulus of elasticity.  From the prototypes I've made so far, it seems to be strong enough, although I reserve the right to change my mind once I get some use out of it.

I've just got the grip head section to a point where I'm reasonably happy with the structure. There will have to be a few more revisions to get the hat switches properly mounted though.

[engines]

I've been working on a simple, reliable friction mechanism.  This version uses a toothed belt (from a recycled 3D printer), belt tensioner, and a lever pushing on the throttle pivot block.  This way I can use the friction knob as it was intended while keeping moving parts to a minimum.

 

[engines]

Quick clip showing the smooth action of the hall effect sensor here:

And attached is the sensor details. It's used with an 8mm cube magnet.

 

 

Edited December 17, 2021 by engines

[engines]

Quick progress update now that I have most of the structure in place.  The photos below aren't the final configuration as I need to redo a couple of parts, but for the most part it's complete.

Each of the three rotational axis will be using the hall effect sensors.  Once I've adjusted a few aspects of the moving parts, I will be ready to functionally test.

I've scrapped the original friction assembly as I couldn't get it to apply enough force within the geometry constraints I had, so I will be resorting to a small damper which will arrive next month.

Some more photos from the front aspect.

[obious]

This looks awesome. Can I ask if you’re using some custom programming for the hall sensor? I’m playing around with hall sensors at the moment but for the life of me I can’t get windows to recognise the full range of motion 

Edited January 12, 2022 by obious