Gazelle Pit

[TripRodriguez]

@xray20 Here is the main forum I used when building my platform, and also this is the supplier of the hardware motion sim board I bought.http://motionsim.freeforums.net/thread/35/trips-ac-hp-6dof-build

 

Now to answer your question. Yes the data is exported through an export.lua, and IMO the exported data from DCS is much better than FSX and P3D.

 

The exported data is first translated by motion sim software, there are several options both paid and free. The one that is by far most highly recommended for flight sims is Ian's BFF http://bffsimulation.com/index.php . After that it goes to hardware, in my case (AC rig) a Thanos Board translates the motion sim data into movement for my drives and incorporates the positional feedback from my sensors, then sends it to the inverters which drive the motors.

 

BFF can do racing as well, but other options have more of a focus on that.

 

As far as building a platform, first thing is that a 6DOF Stewart platform is by far best for flight sims. I was originally going to build a 4DOF due to lower cost, but a very knowledeable member of the flight sim community who worked for a motion sim company talked me out of doing that in favor of going 6DOF.

 

There are a number of major considerations when choosing what type of motors/power system to use.

 

I did an AC motor build with Hitachi inverters which is a mid level cost option. The up side is it has plenty of power and good weight capacity (I was told about 350KG). The down side is the 3 phase motor drive system emits high pitched noise that makes wives very unhappy! It's easily drowned out with loudish head phones so doesn't bother me a bit! Fortunately my wife seems to have gotten used to it after a few months. My only complaint about my rig is I'm having a hard time getting it to be smooth like I feel like it should be for flight. My rig has more torque than I can use. It can easily accelerate the platform much too fast for comfort, but I'm struggling with trying to get the accelerations slowed down to where they feel smooth without slowing it down too much. Tuning these things is a delicate balancing act.

 

I think adding a G-seat is going to be a huge upgrade, in fact you might consider building a G-seat first if you don't want to go too crazy with costs. A g-seat alone is apparently pretty effective and way less expensive. Ideally of course you have both.

 

The cheapest way to go is generally DC powered but generally the weight of the platform has to be pretty low and you might wish for more power.

 

If you are willing to spend the big bucks you can get commercial linear actuators or servo motors.

 

Please feel free to ask me any more questions you have, I'm not super knowledgeable but can answer many questions and point you in the right direction to get others answered.

 

Trip

 

Trip

Thanks Hans.

@trip

Hi Trip, I have been looking at your motion sim and thinking it would be fun to build one.

Two questions to start:

How do you export the XYZ data from DCS? (export.lua?)

How do you transform the XYZ data into positional data for the platform?

I can't find any motion platform group on the DCS forum - is there one elsewhere?

Cheers

Matt

Edited April 4, 2017 by TripRodriguez

[xray20]

@Trip,

Thanks for sharing this info. I spent about an hour on the motionsim forum and there are some great projects going on (including yours). More study is required.

 

I take on board your comment about wifely indulgence. Having just got rid of a half ton of A-10C cockpit with the promise that everything will be smaller, quieter etc. with VR, I have to approach this one carefully. :music_whistling:

 

Gazelle Fly-in this weekend! I'm getting excited.

 

Matt

[TripRodriguez]

I can't possibly express how jealous I am that you can attend that, but I feel much better about it than I did before I was able to share the info with you!

 

Good luck with the wife! My sim takes up a space 6.5 feet wide by 8.5 feet long! Not too bad really, considering.

[xray20]

Gazelle 50th anniversary Fly-In. I get a close look at the controls

 

I attended the Gazelle 50th Commemorative Fly-In at Army Air Corps Middle Wallop on Saturday 8th April 2017. A fabulous day. I have posted a video of the departure of the

military Gazelles on YouTube.

 

 

20 or more Gazelles on the field, many allowing a chance to sit inside and handle the controls (engine off unfortunately). The military pilots were very willing to answer my questions.

Many of my questions about the 'feel' of the controls were answered, with some unexpected results:

Collective

The collective has an adjustable friction grip (the knurled tube near to the quadrant) so it can be adjusted from light, to almost locked. It can never be set too tight to move, however. It will stay in place if half locked, but tends to close to fine pitch if the friction grip is at minimum.

It has detents or click stops at the pitch angles marked on the quadrant. The Army Air Corps have three positions:

IPS - intermediate pitch setting. This corresponds to 8.8° on the DCS model and is never exceeded in normal flight.

 

MPS - maximum pitch setting, corresponding to 9.9°. Used only for combat manoeuvres

 

Full pitch - the end point of the collective. This only ever used for auto-rotation landings. The travel between MPS and Full is strongly spring loaded and the collective is forced back to MPS. The collective at this position is vertical and somewhat behind the pilot's center-line requiring a deliberately awkward arm position.

 

It is not unusual to let go of the collective in level flight to adjust the instruments etc.

 

Cyclic

The cyclic also has a friction lock (the thumb ring like a fuel filler cap at the base of the stick). The cyclic is servo assisted and only thumb and two fingers are needed, with action from the wrist, which rests on the pilot's leg. Later models have a magnetic cyclic lock whch allows the pilot to let go of the cyclic in flight. It is still possible to move the cyclic and fly the aircraft with the magnetic brake on although the resistance is higher.

 

Rudder

The rudder is hydraulically assisted and again is quite light, a bit more than the accelerator pedal resistance in a car.

 

The Polychop Gazelle model in appearance and dynamics and sound appears to be excellent.

It was interesting to see the pilots find the neutral position, adjusting cyclic and rudder with the helo rocking on the suspension of the skids, before lifting off.

 

I didn't get a flight yesterday, but I have put some feelers out and hope for a positive response. I will post a link to some more photos when I have had a chance to edit them.

[hansangb]

very nice! thnx for taking the time

[TripRodriguez]

Sounds like a great success and thanks for posting all the excellent info! Some very interesting stuff there. I hope you get your ride!

[FragBum]

@xray20

 

Thanks for the pictures and info great stuff. :thumbup:

[TripRodriguez]

Thanks for the video! So cool to sit here and watch that and know exactly what the pilot is doing during take-off prep.

[xray20]

Rotor Brake

 

I forgot to mention the rotor brake.

 

Its held in a gate. The pilot pulls it to the right, out of the gate and it snaps forward on a strong spring. It caught me by surprise and it snapped up to the horizontal with a bang (causing a look of admonishment from the pilot).

 

I can see how this would have caused some problems with the simulation. It's necessary to let it off under hand control, somewhat like releasing the handbrake on a car.

 

The fuel control lever is similarly gated and needs to be pulled to the right before releasing.

[TripRodriguez]

That is interesting! It's on a spring in the sim but moves very slowly. On the fuel control lever, it has a gate, but no spring I assume as going full open on it too early can kill the engine?

 

I'll add at least the rotor brake gate and spring I think, not sure I have the room to put a gate on the fuel lever, I'll have to look.

[xray20]

@trip

Confirmed - Fuel control has no spring, its pretty much as per the sim.

[TripRodriguez]

@xray20 Do you have contact info for one or more of the Gazelle pilots you spoke with? Specifically we need one familiar with the SA-342 (not SA-341) to hopefully answer some questions.

 

I'm not sure if you saw but there is once again a big thread going on the DCS Gazelle flight model. I wonder if we might be able to condense the contents of those threads to a handful of concise questions and send them to a real SA-342 pilot for answers, what do you think?

 

I should have thought of this before the event and sent you with the questions in hand!

[TripRodriguez]

Today I finally finished my main panel for the Gazelle cockpit, I can post a pic if you want @Xray20 . Keep in mind, my cockpit too is for VR so the instruments are not functional, just flat images. All switches, buttons, and rotaries will be fully functional.

[FragBum]

Would love to see it Trip, heres my first attempt at a V-Pit well the start of it. :thumbup:

 

https://forums.eagle.ru/showthread.php?p=3120216#post3120216

[TripRodriguez]

 

There it is. @X-Ray let me know if you want me to remove this from your thread, as I can understand if you do. I'll have a Gazelle sim pit thread later, but not starting it until I've got more to show.

 

I have to say even though it has many more imperfections than I hoped, overall it looks better than I expected somehow.

 

This is for a VR pit so the instruments are static images. All switches etc. will be fully functional.

Edited April 25, 2017 by TripRodriguez

[FragBum]

Well it looks pretty damn good Trip there was that "Oh yeah that looks the part" as soon as I saw it. :thumbup:

[xray20]

@Trip - Nice Job! (no problem keeping it on - this is the Gazelle pit thread :thumbup:)

I know where you are coming from. I need some panel switches now and some buttons to do general sim tasks like closing the doors and activating the kneeboard.

 

In the meantime I have made progress on the control. the cyclic has a handgrip and buttons from an old Talon F-15 stick I got for a fiver on EBay. The collective now has detents and a return spring at the maximum pitch setting. It's quite instructive. Flying around at Intermediate pitch gives a nice control response without overcompensation.

 

Re: the flight model questions, I spoke to some guys from the Gazelle Squadron at the Fly in and they were very accommodating. I'll ask them.

[TripRodriguez]

Thanks X-ray. I really like the changes you made to the collective after going to the Gazelle fly-in! I need to put together a parts list for my collective in the next day or two.

[kairuihuaxue]

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I hope I can help you. 

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[kairuihuaxue]

2023/6/10 AM8点53分，kairuihuaxue说：

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[jannickz]

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