1Nm = ~.7 ft·lb. 1 Foot = ~ 300mm. This is similar to the distance to the pivot in most real aircr

1Nm = ~.7 ft·lb.

1 Foot = ~ 300mm. This is similar to the distance to the pivot in most real aircraft.
(F-18 has around ~ 1.5ft pitch, ~1ft roll, if the sources I've seen are accurate)
(the center of the palm may rest as much as 75mm above the base of the grip)

A pull force of ~20lbf for full deflection seems fairly typical of fighter aircraft.
(Looking for data on the f-18 I found a figure stating a force gradient of 3.5lbf/g. 3.5lbf * (7.5g-1g) ~= 23lbf = 31Nm at full aft stick.)
>20Nm seems fairly reasonable if you want to build a realistic stick for a modern jet.

manuvering aircraft without fbw (for instance the p-51) at high speed could easily become a two handed job.(>70lbf) But replicating that isn't really very viable for a ffb setup

Vladinsky•6/11/22, 2:11 AM

20NM wouldnt be a terrible place to be, it would net you about half the stick force of a relatively light stick like the Mirage 2000 using the thrustmaster hornet grip and rhino base format.

WWoodspeople 1Nm = ~.7 ft·lb. 1 Foot = ~ 300mm. This is similar to the distance to the pivo...

Vladinsky•6/11/22, 2:12 AM

The hornet springs give 35-40lbs at full pitch deflection, the excess after the regular lbs/g ratio is used for the AoA feedback.

WoodspeopleOP•6/11/22, 2:13 AM

If I ever finish my diy ffb stick project it would be fairly powerful as to replicate modern aircraft I decided on a design figure of 30Nm.

VVladinsky The hornet springs give 35-40lbs at full pitch deflection, the excess after the ...

WoodspeopleOP•6/11/22, 2:13 AM

Didn't realise that, neat.

Vladinsky•6/11/22, 2:14 AM

Although having used a 10KG force joystick I've become a huge fan of not having realistic forces haha, 4-5KG peak is my sweet spot

WoodspeopleOP•6/11/22, 2:15 AM

Of course directly connecting the motors to the gimbal would be a little overkill. About a 10:1 reduction seems like the most you're going to easily fit in a single stage on a reasonably sized gimbal.

VVladinsky Although having used a 10KG force joystick I've become a huge fan of not having ...

WoodspeopleOP•6/11/22, 2:16 AM

This is a good point, the demands of a simulator pilot are somewhat different to those of a real pilot.

Vladinsky•6/11/22, 2:17 AM

I also ran into some ergonomic issues with the wrist, because it was a short stick the angular deflection was much higher than something in a real aircraft. If it was a full size stick I suspect it would be a lot more manageable

WoodspeopleOP•6/11/22, 2:17 AM

~~How long was the throw?~~
Sorry, brain not 100% on, I meant 'how large was the pivot radius?'.

FFlashgod_VR the question is, what for? why so much power? the rhino base with it's form and ...

Vulkan•6/11/22, 2:17 AM

Base is going to be mounted into directly into the chair, so shouldn't be moving with those forces

WWoodspeople ~~How long was the throw?~~ Sorry, brain not 100% on, I meant 'how large was the...

Vladinsky•6/11/22, 2:18 AM

WW libra base so very roughly 20 degrees

WoodspeopleOP•6/11/22, 2:20 AM

I see

Vladinsky•6/11/22, 2:30 AM

Had to go measure it, about 20cm radius from the base to the stick reference point, middle finger under the trigger. It turned it into more of a wrist action to pull rather than arm.

WoodspeopleOP•6/11/22, 2:31 AM

Ah, that does sound uncomfortable with a large force.

Vladinsky•6/11/22, 2:31 AM

For reference this is the real hornet stick

WoodspeopleOP•6/11/22, 2:31 AM

Yea, I was looking at this drawing earlier for my first comment.

Vladinsky•6/11/22, 2:35 AM

Lots of fun stuff in ADA324124 and for the hornet specifically AD-A256 522 if you haven't seen it

Flashgod_VR•6/11/22, 2:36 AM

i hope you guys are aware that a ffb stick is more a piece of machinery compared against a stick in a real aircraft. it can be dangerous.

Vladinsky•6/11/22, 2:37 AM

Absolutely, I've had the opportunity to use some high power FFB wheels and they're quite something

Flashgod_VR•6/11/22, 2:38 AM

yeah, those are wrist breakers and ffb sticks can turn into melee weapons ;)

Flashgod_VR•6/11/22, 2:40 AM

dcs player knocked out by joystick...

WoodspeopleOP•6/11/22, 2:41 AM

I saw a forum post by someone who mentioned they booted up msfs with the 'push stick back on spawn' option on spawn checked, ouch...

WoodspeopleOP•6/11/22, 2:42 AM

Gonna try not to repeat that one.

Vladinsky•6/11/22, 2:43 AM

yikes

Vladinsky•6/11/22, 2:47 AM

Might be a good idea to position the stick in such a way that you're never in danger of that, regardless for base power

WoodspeopleOP•6/11/22, 2:47 AM

Yea, definitely want some beefy physical endstops to prevent unwanted attacks.

Flashgod_VR•6/11/22, 2:52 AM

still remember my first hours with the G940, had it simply standing on the desk, testing ffb effects... it is very light, compared against the rhino, much weaker power but still wanted to hop from the desk

WoodspeopleOP•6/11/22, 2:53 AM

Yea. I've got a sidewinder I'm using as a ghetto shifter and I'ts heavy enough to keep itself down but it has a fair bit of impulse.

VVulkan Does the rhino come with the larger or smaller motors. And down the line do you ...

walmis•6/11/22, 5:04 AM

Interesting discussion here

I'll chime in. So yeah there are couple of design decisions and compromises for the Rhino. I wanted to make a more accessible base and to keep the weight down while having decent forces. If it beats a Brunner offering then it's a win for me. And the shipping costs worldwide go exponentially with weight

So material selection was based on that idea also. So I consider the Rhino as the 'advanced' entry level FFB device and once this project grows, I'll have more resources to start offering more PRO solutions.

WWoodspeople 1Nm = ~.7 ft·lb. 1 Foot = ~ 300mm. This is similar to the distance to the pivo...

walmis•6/11/22, 5:09 AM

86BLF04 motors with 10:1 reduction should generate up to 40-50Nm

walmis•6/11/22, 5:15 AM

I had this reduction scheme on my first prototype base, 1:25 iirc

Even the 57BLF did provide 5-6kg at the stick (=20-30Nm)

walmis•6/11/22, 5:17 AM

https://www.youtube.com/watch?v=9nuxdO52OqM

YouTubeValmantas Palikša

FFB Joystick force test

walmis•6/11/22, 5:18 AM

pivot to stick base ~38cm

WoodspeopleOP•6/11/22, 5:51 AM

Very impressive as always! I can definitely see the reasoning behind the design decisions with the rhino aimed at advanced entry level, looks like you've got a really nice niche.

WoodspeopleOP•6/11/22, 6:01 AM

I do have one question regarding the motor specs. According to the data from the manufacturer you posted above the 86BLF04 has a continuous torque rating of 1.4 Nm, and a peak rating of 4.2.
How much do the motors heat up when running at peak current? Is it a significant factor?

walmis•6/11/22, 6:05 AM

well, leaving them running at 30A will heat them up in 5 minutes or so, but they have so much thermal mass, that with active cooling that's no problem.

walmis•6/11/22, 6:06 AM

After testing they were still warm after a couple of hours lol

walmis•6/11/22, 6:06 AM

Literally bricks

walmis•6/11/22, 6:07 AM

They absorb about 100-120W at the peak

WoodspeopleOP•6/11/22, 6:07 AM

I see, as long as the average current is below the maximum the cooling can handle, it should be mostly fine? (within limits of course)
I'm sure the inrunner design helps with heat dissipation. Lots of easy thermal access to the stator windings.

walmis•6/11/22, 6:08 AM

Yeah, that's absolutely correct

walmis•6/11/22, 6:08 AM

📃general

WoodspeopleOP•6/11/22, 6:10 AM

Certainly quite beefy.

FFlashgod_VR i hope you guys are aware that a ffb stick is more a piece of machinery compared...

BikerSid•6/11/22, 9:59 AM

I read a good book about the early days of flight simulation with NACA and NASA. They sometimes used hydraulic FFB sticks and the test pilots absolutely hated them and a few were borderline nervous around them.
The analogue computers driving the hydraulics would sometimes do weird and unexpected things, causing the sticks to bite them in painful areas of their anatomy....

BBikerSid I read a good book about the early days of flight simulation with NACA and NASA....

Richard•6/12/22, 10:16 PM

When I worked in flight simulation they had just transitioned from analogue to digital control loading. It was an absolute marvel of engineering. The basic hardware was the same (hydraulics and strain gauges); but the software that controlled it was written in microcode (into a special modified processor that had writable control store) so it could run at 500hz. That's right - the CPU was modified so that they could write software in microcode.

There was a big emphasis on safety and if anything was out by a very small margin then the controls would disengage. What you have to realise is that when the controls were disengaged (from the hydraulics) the stick would move freely.

Quite often during development (and sometimes during training) you'd be flying along and suddenly the controls would disengage. The noise was very distinctive as the hydraulic pressure was rapidly dumped.

Once when I was working on the Swiss Hawk the controls guy had got his signs inverted; so it was effectively a positive feedback loop. So as he pulled back the force was inverted which moved the stick forwards which increased the force being applied. Net result was being pulled into the HUD assembly. Normally as a force was measured on the strain gauge the software would move the stick in the appropriate direction and it would feel as though you were moving the stick when in fact it was the software that moved the stick.

WoodspeopleOP•6/12/22, 11:30 PM

Those are some pretty neat anecdotes.

sko•6/13/22, 5:02 AM

so which grips are we up to now with implementation?

walmis•6/13/22, 5:05 AM

Virpil T-50CM2, Constellation Alpha, WarBRD tested

walmis•6/13/22, 5:09 AM

@sko2408 Which one do you have?

1Nm = ~.7 ft·lb. 1 Foot = ~ 300mm. This is similar to the distance to the pivot in most real aircr

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