Chieftain kit arrival

Forum for discussion relating to the Chietain MBT
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Youngjae Bae
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Re: Chieftain kit arrival

Post by Youngjae Bae » Sat Feb 01, 2020 1:46 pm

Vince Cutajar wrote:
Sat Feb 01, 2020 1:37 pm
This is going to be a very interesting modification which I look forward to follow.

Chieftan had also what I think is called barrel stabilization. I wonder if anybody is going to attempt to implement it?

Vince
In my case, using the three-axis gyro sold on the market, I am trying to control the two-axis control and gyro gain value with a transmitter, which has also completed ordering parts and is waiting.
I hope that everything will be possible by adding one from the supply of Armortek. :mrgreen:

Youngjae

Vince Cutajar
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Re: Chieftain kit arrival

Post by Vince Cutajar » Sat Feb 01, 2020 1:55 pm

In my case, using the three-axis gyro sold on the market, I am trying to control the two-axis control and gyro gain value with a transmitter, which has also completed ordering parts and is waiting.
I hope that everything will be possible by adding one from the supply of Armortek.
Nice. Will surely follow along.

Vince

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Stephen White
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Re: Chieftain kit arrival

Post by Stephen White » Sat Feb 01, 2020 2:58 pm

Vince, Youngjae

Gun stabilisation is a holy grail for Armortek models. It's very much more complex than it looks. I hope with all the expertise we have on the Forum and at Armortek, we can develop a workable solution. I know it's been on the Armortek agenda for some time. I did a lot of experimentation on my Centurion with partial success, enough at least to understand where some of the challenges lie. Here are some of the issues:

- how many axes? Is traverse more or as important as elevation?

- how do you accommodate recoil, which moves the centre of gravity of the barrel in relation to the mantlet? Gun balancing is essential in any event, as is minimising friction with a linear bearing.

- how do you make the drives sufficiently responsive in order to eliminate lag? The current Armortek lead screw elevation system is unworkable (too slow). Servos may work but a stepper motor arrangement might be the final solution. The turret is a big mass with a lot of inertia. The traverse mechanism is a major challenge.

- how do you prevent collisions with parts of the hull which could foul? Do you ignore the problem or fit limit switches or.....

- how do you give the gun a point in space as datum? I'm now very certain that key to this is a so-called six axis sensor package. You need accelerometers, rate gyros and GPS to drive the system. Fortunately, these are available very cheaply. The stabilisation arrays available for model aircraft are not appropriate (you're only stabilising the platform itself rather than stabilising a sub-system in relation to the platform). Camera gimbals are more analogous and offer some promising potential solutions but - they all rely on brushless motors and cameras have nowhere near the same mass as our tank turrets and guns.

- how do you integrate control of stab with the RC system? - the most promising solution I've seen is based on Arduino, which allows the vital tailoring of response which will be required.

There's no doubt with dextrous hands and one stick drive control, you can to a degree simulate stab but a working system would be a big step forward. I've got a copy of a PhD thesis on gun stabilisation in the full size which shows just how complex the physics are so it's worth bearing that in mind in order not to be disappointed when a new, simple solution fails to deliver.

For my part, I got a prototype working on the Cent but found that it struggled with the mass of the turret and gun and quickly got out of phase with the hull. That led to a potentially self-destructive induced oscillation which was fun to watch but not what I was trying to achieve. I think that camera gimbal technology will eventually work for us for the sensor and control part of the package and the big challenge will be the physical drives.

Good luck to anyone trying this.

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John Clarke
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Re: Chieftain kit arrival

Post by John Clarke » Sat Feb 01, 2020 11:07 pm

I had considered a stab system myself, but once I'd got hold of the options pack, I thought I'd better stick with the British tank 2 pounder system. :D
A demented Darlek might be show stopper especially if you can't switch it off.
Now I'm going for a small High intensity LED in the gunners target periscope. Point the whole turret at the target, put a red dot on it and say "yes that's what I'm aiming at".
Great pep talk though Stephen. :lol:
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Re: Chieftain kit arrival

Post by Robert Reid » Sat Feb 01, 2020 11:49 pm

Don't forget that they had gun stabilization on the Stuart in 1940... using Sperry gyros!

But, that said, if you guys can pull off gun stabilization on a 1/6th model in 2020... it will be like a bunch of modelers who can send a 1/6th scale rocket to the moon.

That it's even being considered is remarkable! 95 percent of the world's armies don't have this in their front line armor! And here are a bunch of Armortek guys who can, IMHO, probably pull it off.

I love this place!

Cheers,

RPR

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Youngjae Bae
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Re: Chieftain kit arrival

Post by Youngjae Bae » Wed Feb 12, 2020 2:22 am

As is and to be....

I'm renovating the recoil.
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Re: Chieftain kit arrival

Post by Stephen White » Wed Feb 12, 2020 9:43 am

Youngjae, your work is inspiring and I'm following with great interest. It's great when members feel able to share their progress. Thanks for posting.

One consideration I had when I was designing the recoil and elevation for my Centurion was to maintain access to the bore of the gun barrel. I replaced the LED array supplied by Armortek with a barrel smoke system, which required a 2mm bore silicone tube to run into the barrel from the turret. That had to be flexible enough to work with the scale recoil distance. Would your design allow access to the bore?

I'm also following the discussion on barrel stabilisation and I hope we can collectively find a solution. Best of luck.

Stephen

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Youngjae Bae
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Re: Chieftain kit arrival

Post by Youngjae Bae » Wed Feb 12, 2020 11:23 pm

Stephen White wrote:
Wed Feb 12, 2020 9:43 am
Youngjae, your work is inspiring and I'm following with great interest. It's great when members feel able to share their progress. Thanks for posting.

One consideration I had when I was designing the recoil and elevation for my Centurion was to maintain access to the bore of the gun barrel. I replaced the LED array supplied by Armortek with a barrel smoke system, which required a 2mm bore silicone tube to run into the barrel from the turret. That had to be flexible enough to work with the scale recoil distance. Would your design allow access to the bore?

I'm also following the discussion on barrel stabilisation and I hope we can collectively find a solution. Best of luck.

Stephen
I intend to share the whole process if I think the personalization I try is valid.
However, even if I hear that I am valid, I will ask for the opinion of Kian before making it public.

The main gun and turret stability I tried were both conceptually completed and the foundry mechanical review was finished, and all the materials for the dispersion and control of the torque were completed.

First of all, I'll explain the personalisation direction of the recoil.
Spring-type pneumatic cylinder, 24V-solenoid valve, two-way BEC to use servo signals, 750CC air tank and fittings.
I use a springair cylinder to make sure that the main gun's quick retreat is pneumatic, and the slow recovery is springing, and these instruments are common on the market.
The advantage of this approach is that all LED, sound and motion signals provided by Armortek are used without conversion.
The smoke effect of the main gun can be expected by using the air that is then purged through the small dry-ice chamber as a chimney.
For example, both the bore size of the cylinder and the number of strokes required have been designed.
However, the tension of the spring to handle the mass of the main gun of more than 2.2 kg needs to be checked.
I have already been wondering about sector production and will arrive at me tomorrow.
Perhaps I expect it to be validated in a few days.
Considering this behavior, the frame inside the main gun is from yesterday.
But I modified the connection point of the linear actuator to stabilize the main gun in the frame last night.
Frames are free from interference in all movements.
Nevertheless, Battery intends to switch to a smaller, more speed-sensitive one you talked about at another forum.

Personalisation for horizontal stabilization of the turret is described.
I thought that it might be a burden to hold the rebound torque when turning a large turret, so I prepared a motor, gear, and fixed frame by dividing one motor and one gear into three and waiting for the motor to arrive.
I'll share this with you if there's no problem after the test.

The vertical stability of the main gun is waiting for the material, with the power, operating speed and operating length of the linear actuator to control the main gun, and the location and panel of the new sliding.
The connection point of the linear actuator is also a very important point.
I will attach the signal to the off-the-shelf Gyro between the motor driver of Armortek Motion Controller B and the receiver to try to control it and then edit Arduino if there.

It looks complicated, but it's too simple to go over P&ID.
Personalization provides a lot of fun.
Please consider that my reply is delayed or delayed on the other side of the globe. :mrgreen:
Have a good day.

Youngjae

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Re: Chieftain kit arrival

Post by Youngjae Bae » Fri Feb 14, 2020 2:59 am

Based on the design, I built a recoil base, a large counterweight, a cylinder and a hanger-type electric actuator base, and a slip ring hole was machined on the actuator base. :mrgreen:
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Chang
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Re: Chieftain kit arrival

Post by Chang » Fri Feb 14, 2020 7:42 am

Hi Youngjae,
One question. What's the reason to instal a longer/larger counterweight? Isn't it going to reduce the gun elevation angle?
Regards,
Lerh Chang
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Youngjae Bae
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Re: Chieftain kit arrival

Post by Youngjae Bae » Fri Feb 14, 2020 8:22 am

Chang wrote:
Fri Feb 14, 2020 7:42 am
Hi Youngjae,
One question. What's the reason to instal a longer/larger counterweight? Isn't it going to reduce the gun elevation angle?
Regards,
Lerh Chang
You can understand the principles of seesaw.
Reduce the moment difference between the main gun and the inner end to create a natural equilibrium as much-needed.
Of course, you have to think about interference when the mass grows, but it takes into account the way you create the maximum angle of motion on the cross section and the way you make the difference on the floor.
I have also applied several different methods of dividing the number of instruments in the actuators, considering overcoming the inertia as the mass increases.
This only takes into account the functions shown.

Youngjae
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Re: Chieftain kit arrival

Post by Youngjae Bae » Fri Feb 14, 2020 10:33 am

Check before installing hanger type actuator base
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Re: Chieftain kit arrival

Post by Youngjae Bae » Mon Feb 17, 2020 10:20 am

I checked the tension of the main gun return spring, made sure there was sufficient force and finished some work.
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Re: Chieftain kit arrival

Post by Youngjae Bae » Wed Feb 19, 2020 6:02 am

Today, I connected main gun and did a motion test about the recoil.
The hand motion was as expected and next I will connect the air system.
And I am going to test it in a reduced weight inside. :D

Youngjae
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Re: Chieftain kit arrival

Post by Youngjae Bae » Fri Feb 21, 2020 1:27 am

The recoils of chieftain are working as I intended I'm only doing a motion test with my hands, but it's very smooth than the original, because the surrounding parts to connect the pneumatic are not ready yet.

The recoil renovation is being carried out in conjunction with the main Gun stabiliser.
Although progress is a bit slow due to the surrounding situation, the pleasure of each move is also great as expected.:mrgreen:

Youngjae
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