Arjun Main Battle Tank (MBT) Mark II

[ersakthivel]

the gunner's head is at least a feet above where it should be.

If your drawing is tru then the gunner's head will hit the display in front of the Tc if he just shakes his head,

But in real world the display is atleast more than 400 mm above the gunner's head.

It is clearly shown in the picture below that the Tc's seat is well above the gunner seat back rest but you continue to ignore it.

Look at the picture below we cannot even see the gunner's back rest in this picture, It is well below the Tc seat,

The Tc's seat font edge is right behind the front edge of the crew hole circle meaning it is more than 2000 mm behind the turret front tip(including the gun covering plate)

because the gunner's seat back rest is clearly visible along with the gun edge in all the photos taken from above the crew hole,

So the gunner's seat which is right below the Tc seat front edge must be at a point 2000 mm behind the gun front tip(including the covering plate)

but in your drawings you consistently mark it at close to 1600 to 1700 mm behind the turret front tip, which is another mistake.

The resulting knee space gap for the Tc (because of this wrong height of the gunner) is one of the reason you are getting lower LOS,


I am sure about this because at 11.02 seconds(not hundred percent sure about the minutes and seconds but it is clearly there and I have posted it already in ARJUN MBT thread, I will locate it and get back) in blue mango film I can clearly see the Tc 's knee above gunner's head

And as usual no dimension markings to check the correctness of the model

 

[pmaitra]

Ok, so folks, here are the new dimensions.

@Dejawolf, thanks for the new image.

Anyway, the model is a good piece of work, but I think there are some assumptions. Not saying which one is incorrect, but both surely cannot be correct.

[HR][/HR]

Allowing for some perspective error, I compared the two figures, and I am getting the impression the image above has incorrect dimensions:

@ersakthivel and @Dejawolf, stop fighting.


@Dejawolf, can you please post a straight line projection instead of a perspective projection of your model. I am looking at the same image (top) I have posted here. It would be nice if the focal axis is horizontal to the ground and orthogonal to the side of the turret.

Thanks!

that's because you're using different points of measure. in first pic you're using front of gunshield, in second pic you're using front of turret.
also, turret is taller at first point of measure vs second point.

I know. I am trying to get as accurate as possible. Please respond to this post.

length from back of eyepiece to front of GPS assembly is about 110cm.

 

[Dejawolf]

Extend all the dimensional lines till the scale and

use the front tip of the gun shield plate for all measurements ,

every one can see who is right or wrong,

it can be over in minutes.

it will never be over because you'll never admit you're wrong.

 

[Dejawolf]

Ok, so folks, here are the new dimensions.

@Dejawolf, thanks for the new image.

Anyway, the model is a good piece of work, but I think there are some assumptions. Not saying which one is incorrect, but both surely cannot be correct.

[HR][/HR]

the second one is the older one, i did some changes to the height of the front turret armour facings. they're not as tall as on the old model, to accomodate a slight lip in the lower portion of the turret.
also, again you measured from front of gun tip.
here's without the gunshield:

 

[pmaitra]

the second one is the older one, i did some changes to the height of the front turret armour facings. they're not as tall as on the old model, to accomodate a slight lip in the lower portion of the turret.
also, again you measured from front of gun tip.
here's without the gunshield:

Thanks. Yes, because the second one has a colour picture superimposed on a line drawing. The colour image probably comes from your model, and you probably made some changes later on. So the ratios are different.

I knew something was amiss, and now I know it was not an optical illusion on my part.

 

[ersakthivel]

Thanks. Yes, because the second one has a colour picture superimposed on a line drawing. The colour image probably comes from your model, and you probably made some changes later on. So the ratios are different.

I knew something was amiss, and now I know it was not an optical illusion on my part.

the height of the gunner's head is clearly wrong read my post 241

See the height of the gunner head which is far below the white display in front of the Tc in real life photo

Compare the actual position of the gunner's head with the position in the model below.

In order to provide the knee space in the wrong arrangement below he is moving the gunner far in front which is another factor in showing a wrong LOS behind main sight.

See the correct position of the gunner seat back rest in the picture below , it is visible from photo taken above in line with the edge of the gun,

So it can not be that far forward as shown in the 3d model,

We can even see the circular step corresponding to the crew hatch entry whole near the base of the tc seat.

It is actually more like it with the gunner seat back rest close to the 2000 mm point from the gun covering plate front tip of the turret.

 

[pmaitra]

the height of the gunner's head is clearly wrong read my post 241

Yes, I saw that. The eye-piece should be near the eyes, not the chin. I think it is work in progress, and he will correct it.

 

[Dejawolf]

Yes, I saw that. The eye-piece should be near the eyes, not the chin. I think it is work in progress, and he will correct it.

seat height of gunner has been corrected:

 

[ersakthivel]

seat height of gunner has been corrected:

What should be corrected first is the position of the gunner's seat back rest at a point 2000 mm behind the turret front tip(includes gun covering plate), See the blue line below

The if we deduct the 700 mm for the main sight cutaway from this 2000 mm we get 1300 mm,

All we have to deduct from this 1300 mm is the leg space for the gunner, which may not be more than 600 mm,

So 1300 mm-600 mm comes to minimum 700 mm.

 

[ersakthivel]

Yes, I saw that. The eye-piece should be near the eyes, not the chin. I think it is work in progress, and he will correct it.

it is in this page that militarysta posted the picture of main sight in post no-4857 in Arjun MBT thread

and claimed since this is the LEO main sight it must also look similar on Arjun,

the following is his own words,

EMES-15 from leo-2 and similiar in shape will be Arjun main sight.

that was what I repeated ,since no one challenged it.Now methos is showing the scan of some crumbled image and accusing me of lying!!!!, where was he then?

http://defenceforumindia.com/forum/indian-army/9558-arjun-main-battle-tank-mbt-324.html

Aslo in post-4858 in the same page above Dejawolf has posted the following picture, from the blue mango film which shows that most of the Tc's knee space goes above the gunner's shoulder.

So it is not that he was not aware of the seating arrangement in Arjun

Also we can see the tc's Knee well right of the gunner head in the following screen shot from blue mango film.

I used the same main sight analogy in th following argument in the following page as well

http://defenceforumindia.com/forum/indian-army/9558-arjun-main-battle-tank-mbt-327.html

the so called visible roof vision block (painted in red ) seems to be well left of the binocular like eyepieces in gunner's main sight.

So according to this schematic photo of the the gunner's main sight it is clear that the left hand side border of the turret front end main sight optics(colored in dark green ) is almost aligned in vertical line with the binocular like eye pieces on gunner's main gunner sight vision block.

The so called visible roof vision block painted in red lies left of the binocular like eyepieces of gunner's main gunner sight vision block.So what it is and whether it lies directly behind main sight needs some explaining.

Because according to the schematics of the gunner main sight instrument standalone photo anything that lies left of the binocular like eyepieces of gunner's main sight vision block cannot be right behind the gunner's main sight optical front end (colored in dark green) at turret front.

 

[ersakthivel]

What could be the width of the breach block?

 

[ersakthivel]

Inside Out - Arjun Main Battle Tank - Discovery Channel's Documentary On DRDO on Vimeo

We can watch the Arjun MBt documentary here.

 

[ersakthivel]

for A1 LOS of 640 mm the LEO doesnot seem to have so much of composite armor LOS thickness behind main sight,

So Arjun with a longer turret , with some slant on the roof top vision block can achieve the same LOS, I don't know what is the song and dance all about ?

 

[ersakthivel]

This photo above again clearly shows the pivot base f the hatch right below the vertical crew hatch cover compare it to where it is in the picture below, where it is wrongly marked to be placed behind the vertical hatch cover .

In fact if you extend the downward vertical dimension blue line from the pivot base on the picture it will be more than 250 mm behind i.e around 2750 mm.

But in line drawing it is placed correctly at 2500mm

 

[methos]

So Arjun with a longer turret , with some slant on the roof top vision block can achieve the same LOS, I don't know what is the song and dance all about ?

The Arjun's turret is not longer than even the first Leopard 2 turrets.

that was what I repeated ,since no one challenged it.Now methos is showing the scan of some crumbled image and accusing me of lying!!!!, where was he then?

You did not repeat his words, you said that this image would show the gunner's sight. It does not.

 

[ersakthivel]

The Arjun's turret is not longer than even the first Leopard 2 turrets.




You did not repeat his words, you said that this image would show the gunner's sight. It does not.

if you think so please post the Arjun turret and LEO turret sideviews with dimensions and source

What source you have to say it is not like that in Arjun any source?

Also what do you think of the massive breach block of the gun near the gunner, drawn by dejawolf in the draw below,

It seems to have a width of close to 600 mm atleast,

Since you claim to be tank professional to load a 120 mm dia shell what should be the width of the breach block?

600 mm?

It is only because of this massive breach block that the gunner seat seems to be so far away from the turret center, what is your views on this?

In the bluemango screenshot below the better part of the gunner seat seems to be behind the GAP between the main sight cutaway and the gun covering plate,

is it consistent with the drawings above?

 

[ersakthivel]

Note : Arjun in expos are mostly prototypes, In 2010 these was a operational example put in Expo but entering that vehicle was restricted, Then in 2012 they bring a prototype in which entering was allowed..

The above is the post by Kunal on the page below,

So we are yet to see the photos of operational model inside, and we don't know whether the Arjun that was shown in blue mango film is prototype or operational one.

http://defenceforumindia.com/forum/indian-army/9558-arjun-main-battle-tank-mbt-336.html

As this main sight schema posted by Dejawolf must be from 20 year old India-Today museum picture,

and we don't even know if it belong to Tank ex or the discarded old prototype of 40 ton 100 mm gun Arjun's

It is quite possible that the main sight would have been updated to latest level as IA won't take decade old sights on new tanks

The Arjun's turret is not longer than even the first Leopard 2 turrets.
You did not repeat his words, you said that this image would show the gunner's sight. It does not.

So do you have any source for the date of this India today image for the main sight?

or is it the one that is presently on Arjun?

if you have please post.

So this is the main sight schema of Arjun,


Do you have any proof to contradict this?

or do you have any evidence to back your claim for a different arrangement?

 

[ersakthivel]

another nonsensical statement by Ershaktivel. nothing new from those fronts as usual.

green line indicates center point of gunners seat.
how about you check your "facts" before going on a long tirade about things.

The above is your model which has a gap equal to the width of the hatch cover between the hatch edge and the outer turret wall ,

indicating just 500 mm gap besides the hatch is available on the turret top between the edge of the hatch cover and the outer turret side wall,

But in the image of operational Arjun below the same distance seem to be almost 1.5 times the hatch cover width i.e close to 700 mm,

Why is there such a large difference?

SO atleast now tell me what is the width of the ARJUN at the center of the turret ,

What is the width of the hatch cover?
Is it 3.1 meters or 3.2 meters or 2.9 meters?

SO what is the width of your hatch cover?

http://defenceforumindia.com/forum/indian-army/9558-arjun-main-battle-tank-mbt-344.html

You were there when it was discussed in the page above as being somewhere between 53 to 58 cms.

If you agree the turret must be 3100 mm plus wide

But didnot give any reply then, So how many mm did you give to your hatch cover width?

Above pic is LEO turret top view,
What is the distance between the back wall of the main sight cutaway and the roof top vision block in LEO?


We all accept that below is the photo of the Arjun turret,

To the bare eye the distance between the back wall of main sight cutaway and the start of the vision block

is almost equal to the

crew entry hole for TC or the vertical standing hatch cover width

SO it must be 500mm plus at bare minimum,

How come you got 300 mm measurement?

 

[ersakthivel]

 

[Dejawolf]

The above is your model which has a gap equal to the width of the hatch cover between the hatch edge and the outer turret wall ,

indicating just 500 mm gap besides the hatch is available on the turret top between the edge of the hatch cover and the outer turret side wall,

But in the image of operational Arjun below the same distance seem to be almost 1.5 times the hatch cover width i.e close to 700 mm,

Why is there such a large difference?

SO atleast now tell me what is the width of the ARJUN at the center of the turret ,

What is the width of the hatch cover?
Is it 3.1 meters or 3.2 meters or 2.9 meters?

SO what is the width of your hatch cover?

http://defenceforumindia.com/forum/indian-army/9558-arjun-main-battle-tank-mbt-344.html

You were there when it was discussed in the page above as being somewhere between 53 to 58 cms.

If you agree the turret must be 3100 mm plus wide

But didnot give any reply then, So how many mm did you give to your hatch cover width?


Above pic is LEO turret top view,
What is the distance between the back wall of the main sight cutaway and the roof top vision block in LEO?


We all accept that below is the photo of the Arjun turret,

To the bare eye the distance between the back wall of main sight cutaway and the start of the vision block

is almost equal to the

crew entry hole for TC or the vertical standing hatch cover width

SO it must be 500mm plus at bare minimum,

How come you got 300 mm measurement?

hatch width is 55cm, turret is 296cm at it's widest, and 277cm at the very front. gun breech is 55cm wide.i fail to see how this relates to turret front thickness...