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D/229 Molevich is building an Mi-24 cockpit in anticipation of the DCS module.

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D/229 Molevich is building an Mi-24 cockpit in anticipation of the DCS module.

Post by (D/229) Molevich on Wed 27 Jun 2018, 08:11

GunfighterSIX suggested I post the story of my Mi-24 Cockpit development, so although there are various posts around on here about it, I have decided to make a definitive and chronologically accurate document about it.

I have been a big fan of DCS choppers since the arrival of the Black Shark, many years ago. I have an inexplicable affinity with the Russian hardware, and so when Belsimtek released the Mi-8 it was a no-brainer for me. I simply adore this module.

I have always made things. I am not an engineer, but I have a good sense of 2D to 3D conversion, and am used to measuring twice and cutting once. In my careers, I have worked as a carpenter/joiner, a fashion designer and tailor, and a special effects and prop maker.

My first major sim-pit development was to customise 2 x MSFFB sticks and a CH Fighterstick into one Cyclic control stick, following PeterP's guide on ED forums some years back. Having achieved that, I proceeded to design and build a collective with a capable button box head and twist throttle. Having wired that up to a Bodnar board, I swore to never do a switch matrix wiring job again! It was a bit crude, but worked very well.








The collective design later served as the principle for the collective lever I made this year for Gizzy, to attach to a TM Throttle unit.



So in 2013 I had caught the controls-building fever.... I am still not cured.

Then two things happened.

While researching "force-feedback", I came across Salty's plans to build a Huey style setup with home-built force gradients.
Salty's Huey Force Gradient.

And while browsing eBay for real-world cyclics to build in to a sim-pit, I came across these.


Impossible to resist, I negotiated a best price and bought them.

These items became the core of my sim-pit project, to build a force feedback cyclic and collective using magnetic brakes, communicating with DCS via a Bodnar board, and the mechanics to all sit neatly (though I later discover, inconveniently) beneath a seat from a sports car, also bought on eBay. Love eBay!


Last edited by (D/229) Molevich on Sat 30 Jun 2018, 08:51; edited 2 times in total
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(D/229) Molevich
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Re: D/229 Molevich is building an Mi-24 cockpit in anticipation of the DCS module.

Post by (D/229) Molevich on Sat 30 Jun 2018, 08:37

So, there is quite a back-story to these Russian sticks. When the Berlin Wall came down in 1989, the British MOD acquired an East German Mi-24, which was brought back to the UK for analysis. They then proceeded to use it as an ordnance test target, and literally shot it to pieces over a few months.... One of the technicians finally salvaged the sticks and took them off base, stashing them under a bed for 28 years. Then one day, he decided to clear out his house, and contacted an aviation parts trader, and that is how I found them on eBay. They are from the copilot/gunner's seat compartment.

I had already started my magnetic-braked force gradient system with a Lynx cyclic I had acquired when these Royal Navy choppers started to be decommissioned. (Its amazing how variable the pricing of these items can be! From £85.00 to £1000.00 for identical items, you really have to shop carefully... some traders really take the piss.) I sold it on for the same price I had paid, through ED forums.

Mag-brake and force-gradients setup: gimbal made from box profile aluminium stock, motorcycle steering dampers from eBay, magnetic door-holders and drawer sliders from Amazon, MDF and other timber mostly from salvage. Compression springs from various places, lots of trial and error to get the right pressure. Bearings and pivots from eBay also. A Leo Bodnar board to read and communicate all the inputs from both Cyclic and Collective.





I did not make dozens of drawings, calculations, plans, etc. Very much a case of working with available components, the tool set I have, and the skills I have too, mostly joinery-based. But I am a garment designer/tailor by training, so I am used to measuring and fitting, pattern making and 2D to 3D modelling and making. A lot of trial and error, testing and adjusting. There were rough sketches of course, pages of sketch and pocket book designs, worked out in my head before proceeding to make.





The trimmer button on the cyclic is a PTM button, ie Push to Make contact. But in order to make the magnets release the brake on the force-gradients, I needed to have the trimmer button break the contact, ie PTB, Push to Break contact. I spent hours pondering how to achieve this, scouring the net for methods and ideas. (I have little to no electronics knowledge, but have learnt a lot in these past few months!) The solution is a relay, a switch which when activated by the Trimmer button, an electro-magnet pulls a lever to break the current-flow to the door-magnet Brakes holding the force-gradients in position. This also meant that the Trimmer function would need to be independent of, and isolated from, DCS software's Trimmer behaviour. The Mag-Brakes, activated and controlled by pushing/releasing the Trimmer button, would hold the cyclic in position. (I have just recently added a spur of wiring from the Trimmer circuit to my Bodnar board, with a diode to reduce the 12V current, which now communicates the Trimmer actions to DCS).

The relative angles of the Cyclic would be read by a pair of Hall Sensors from magnets rotating away from or towards them. 6mm round Neodymium magnets were mounted into small blocks of plastic and Superglued onto appropriate positions on the Cyclic stick or gimbal to move towards/away from a fixed positioned Hall sensor each.



At this stage, the Cyclic Grip was still unconnected, and the wiring of which a later task, but the Trimmer could be tested with a simple PTM button. Working out how all the Grip's wiring would work would prove an interesting conundrum. I will come to that in a later post.

Having only the collective lever, I needed to build a cradle and pivot for it, and having found a scale drawing of this collective system, I cut one out of MDF and bolted it together. I was never completely satisfied with this wooden solution, but it worked, and proved a viable test bed for the development of the Collective Brake, the Throttle Grip mechanics, and worked in this way for several months (until a new solution was found... more later!) The Collective Brake mechanism uses a similar solution to the Cyclic's Trimmer, with it's own 12V supply and Relay. I have subsequently changed this mechanism to be more like the Cyclic's, as the Brake was too "hard" and jerky.





I will post more on this soon.
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(D/229) Molevich
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Age : 57

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