Author: hc625ma

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Trying latest stuff in X-plane

Finally, after quite a long process of designing new things and upgrading old, I can relax for a while and fly to my heart’s content: stuff needs testing. I try to fly every evening, sometimes in DCS, sometimes – in X-Plane. I like both of them: DCS for the Huey, which feels alive, X-Plane for Ortho4XP, VATSIM and the opportunity to fly around the world.

Sometimes it’s a bit hard to go from DCS to X-Plane and fly perfectly: the way these sims handle controls input feels very different. Usually, I try new hardware in DCS at first, because its flight model is better. I have been flying there for a while lately, even had a chance to lead a large enough formation, and could say nothing bad about the new gimbal.

Today I decided to go on with my X-Plane journey across the US West in a 407, doing a short Derby (KLOL) – Silver Springs (KSPZ) leg of the route. After getting used to more sensitive controls response of the 407, the flight has been a pure joy. I have started the flight with 80% sensitivity mode enabled but quickly switched to 100%. The gimbal allowed for slightest adjustments to be made with cyclic. This time I used force trim function in flight a few times, to hold the stick while I’ve been looking at the map, and to try 407 specific “electric” cyclic movements with a hat switch.  With rubber bands now present on the gimbal, it holds and centers cyclic stick quite well, now I use force trim mode on the ground only when I need to remove cyclic stick to go pour myself some tea =)

So far the gimbal feels perfect. It’s very precise, maybe because of a stronger mechanics, there seems to be no backlash at all. The collective with a pneumatic mod still holds together and feels great as well. I tried adding a few drops of bicycle chain oil to the tensioner, this way it can strengthen the assembly, yet not affect smoothness of travel.

Overall the whole set is very precise and smooth, probably leaving nothing more to wish for, except maybe pneumatic mods for cyclic and pedals =)

Bell 407 in Silver Springs
vfrmap.com is awesome, especially with Ortho4XP!
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Throttle quadrant released!

I have printed the quadrant, its parts seem to fit together quite well. I have also added firmware for it, for now, it supports 3 axes (3 more can be added easily).

Each slider has a reverse mode, programmed as a separate axis, so we can fly STOL aircraft =) This is the first version of the software, more features will follow. Let me know if you have ideas of useful functions for it!

Simchair MKIII universal throttle quadrant
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Simchair MKIII universal throttle quadrant

I really like flying helicopters, but sometimes I just want to take that Cessna 172 for a ride. Sometimes, I like flying TF-51 in DCS.  Sometimes I fly STOL aircraft, and I know some of my friends love flying jets.

I have made a single prop GA control panel with three axes earlier, but that one only has 3 axes, and most of the times I am too lazy to go fetch it from the shelf and mount to the table. That’s why I decided to make something universal, that will fit the standard IKEA GUNDE chair frame, somewhere on top of the collective lever base. I want it to be connected and active simultaneously with other stuff at all times (I think we all can find a good use for some additional axes).

I also want it to be modular (stackable, from 1 to 6 axes, for now, tell me if you need more!), and I want full reverse support (there’s a problem with it usually). I don’t think it needs to resemble any particular aircraft, so it can stay universal =)

Here’s what I’ve come up with so far =)

Simchair MKIII universal throttle quadrant

It uses all of the standard potentiometer’s 300-degree travel range. Forty degrees of travel is reserved for reverse operation (various types of reverse will be supported in software), then there’s a small gap with a tactile detent, and the rest of its travel is used for main axes. I will start printing it soon and release it after I  check that parts fit together properly.

Stay tuned!

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Pneumatic mod counterweight design improved

I have found that an issue with the collective lever being a bit too stiff was not due to the counterweight position, but rather because of how upper cylinder hinge was assembled. I have improved this unit and achieved silky smooth travel regardless of a position of the counterweight. Thus, I decided to move it to where it can be barely seen, to improve the overall look of the lever:

A better counterweight housing design
It is almost completely hidden under the chair
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Strengthened gimbal released!

As I have promised, the gimbal is finally released for public testing =) Also, for those willing to try other two designs (MLX90333 based), you can find their dev source files under “dev” directory.

Let me know if you guys have some cool ideas! I will be adding the pneumatic mod for these as soon as pneumatic cylinders arrive. While they are en route though, I am going to make some flying so I can test the new stuff properly.

Here are some pics of the new stuff =)

The strengthened 608zz and SS495A based gimbal
Single collective lever with the pneumatic mod installed
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Strengthened gimbal first flight impressions

I have finally managed to build the gimbal, and even tried flying with it on Aerobatics Online Caucasus sever in DCS =)

I can say it’s great! For now, I’ve used rubber bands for stick centering, and they work pretty well. I noticed that I haven’t been using the software force trim function much during this flight. A lot of heli pilots were online, so I’ve had a great opportunity to put both the gimbal and pneumatic mod for the collective to a good test 😀

I am waiting for 50mm MAL16-50 pneumatic cylinders to arrive, hopefully with them installed the stick will feel perfect.  The collective pneumatic mod still holds together, I am beginning to think it’s really safe to use. A couple more weeks will show if I am wrong =) The new gimbal will be released tomorrow, if time permits, I will also be making a couple of videos about the new stuff soon.

Stay tuned!

Me leading a humble formation 😀
And following another ship, the gimbal has been performing great!
Feels fine when maneuvering in ground effect as well =)
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Thoughts on MLX90333

After finally getting some long enough sleep I thought again on my failed attempts with a Melexis sensor. The sensor itself is quite precise and has some DSP onboard, so I tried it again with a spherical gimbal and noticed that depending on how close a magnet is to the sensor, it outputs not a circle, but a square, inclined to 45 degrees. I thought, “- what if I simply cut excess values and make it a square?”, and did just that. The idea behind it was that jitter of the point in a joystick tester sketch seemed minimal,  so the physical precision of the sensor looked like being enough to work well. As long as we have a 15 bit external ADC that powers our gimbal, we should still have something like 4096 points per axis even with this reduced range, which is plenty.

Now, if we use a disk magnet instead of a square one, unarrested twist axis is not an issue anymore, it doesn’t affect X and Y positions in a big way. So this design seems to be perfectly fine for vertical sticks, or sidesticks, and I think with a pneumatic mod it can be as good for everything else. Its beauty lies in its mechanical simplicity, only a few parts are needed, it can be quite small in size.

I think I will make, test and publish both versions so everyone will be able to choose something for himself =) There’s also a third version, the 608 and MLX based one, its fate will depend on a degree of success of the spherical bearing based one =)

 

Meanwhile, some progress on the 608 and SS495A based version:

Reinforced 608 and SS495A based gimbal
The gimbal itself is quite strong, it should be able to handle the load!)
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News on a strengthened gimbal

I’ve printed and assembled both versions I was talking about in the previous post, and sadly, I had to revert to using SS495A sensors. That’s because the MLX sensor is not so good at displaying values at the angles of the square, like x:1000,y:1000 or x:10,y:10. It also has quite a high jitter near edges of axes. If someone has some experience with these MLX sensors (I am probably doing smth wrong) plz share it with me =)

Meanwhile, I’ve redesigned the new gimbal for use with trusty old SS495A sensors. I am pretty sure it still needs some adjustments, but it uses the same distance from sensor to the magnet, and same 6x6x4 magnets (5x5x5 mod will be available as usual) as well, so I think we will see it in action soon enough.

Here’s how it looks:

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Thoughts on strenthened flight stick gimbals

I am now working on two reinforced gimbal variants. One of them is based on an ordinary 608 skateboard bearings, another one – GE25 ES-2RS spherical bearing. Both of them will be able to handle springs, rubber bands, pneumatic cylinders, etc. A CJMCU-93 module (MLX90333) is used as a magnetic field sensor.

The fate of GE25 ES-2RS one depends on whether I will be able to prevent it from twisting or not (i have an idea involving _| shaped bracket, 2 pneumatic cylinders, and 2 spherical heads now). If you have some ideas about how to lock “twist axis” of a spherical bearing, please share them in comments =) Here are some pictures of the GE25 testbed and 608-based design.

608-based strengthened gimbal
GE25 spherical bearing based gimbal, it’s cute, but the “twist” axis kills all the fun!