Arjun Main Battle Tank (MBT)

[ersakthivel]

where is the roof vision block shown directly behind the orange FCS box in the first picture above?

 

[ersakthivel]

the roof vision block according to this drawing is between 1300 to 1400 mm behind the turret gun front tip.

it is located at the back edge of the iron rod like holder , So the roof vision block is close to 1300 mm behind the turret gun front tip.

Even if the vision block is vertical (but it looks slanted from all indications)

So if we deduct 700 mm for the main sight cut away a distance of close to 600 mm is available straight away for the LOS behind the main sight.
But in LEO it is less than 100 mm behind the gun front tip

But in LEO the same distance is less than 1000 mm.

So extra 300 mm is available even if the vision block is vertical, and no armor columns behind the main sight. But the bumpy folded inner armor wall behind the main sight means there is a variable thicknes

 

[ersakthivel]

this image is a comparison of the distances of roof vision blocks over gunner's main vision block in ARJUN and LEo-2

 

[ersakthivel]

The shadow of the turret falls on the hull at the third blue line from the top.

it is the place where turret's side wall projection on the hull would fall.

The blue rectangle drawn on the TC's crew hatch cover represent s the true length of the hatch cover .

This rectangle is projected in the correct plane on the hull ,

found out by the downwards projection of the line joining the two hatch covers on the turret top,
to the top of the hull.

This is the perspective drawing as far as I know,

Width over track is 3540 mm.


About half of the crew hatch is enclosed between the red line an the blue line.

The red line indicates the track width border of 3540 mm. Because there needs to be some gap between the inner side of the side skirt and track edges.

That is about 0.50x550 mm=220 mm
3540-(220x2=440 mm)= 3140 mm is the width of the ARJUN turret.

There needs to be a correction factor for taking the same length turret width line which is situated at a depth of the close to 1.5 meter from hull plane . If we apply that the hull width is only going to increase, not decrease.

Because the fixed length rectangle on the hatch cover will measure less length if we bring it in front by 1.5 meters on the hull plane, nearer to the observer( in this case the camera )

Since my opponents here will not accept it as they don't have any idea about Perspective distortion, I haven't included it here.

If some people say the hatch cover is just 500 mm in width , according to this measurement technique the turret width is only going to increase,

So no can try to wiggle out saying that if the hatch cover width decreases the turret width will also decrease when we go for a staight on hatch cover measurement like the one below.

Even if you take a worst case scenario of 3000 mm turret width, giving a very large margin of 140 mm for inaccuracies

1500mm is the distance between outer most side wall of arjun side turret and the turret center line,
1200 mm is the distance between the two crew hatch centers,
1200/2= 600 mm is the distance of Tc' seat edge from the turret center line,
So 1500 mm-600 mm=900 mm is the space available besides the crew hatch center and the outer most side wall of ARJUN turret,

The composite armor cavity in the photo above confirms that.

Also if you look at the following line drawing posted by PMAITRA the distance between the standing vertical crew hatch cover base and the tip of the gun mantle plate on the turret front is 2500mm.

The roof to vision block over the gunner's main FCS box is situated roundabout at the middle of this 2500 mm distance, that is close to 1300 mm behind the front tip of the gun mantlet plate on the turret front.

SO if you deduct a 700 mm for the main sight cutaway a distance of atleast 600 mm is available as LOS thickness behind the main sight,Even if there is no extra armored block behind the main sight.

But according to the evidence from photographs the inner turret armor wall behind the main sight is bumpy with many folds indicating extra armor support behind the main sight.

And the absence of empty space behind the sloped orange FCS box also indicate there is extra armor behind the main sight.

So no need for revolutionary rescaling techniques on obscure drawing like the one below,

So revolutionary PHD thesis like the one on the draw below is completely fictional.

SO I don't see any need to change my views based on any 3D model provided here.So end of this acrimonious debate must be in sight as there is no possible reason for any poster dispute this measurement.

 

[ersakthivel]

So stuff like the one above is obviously false propaganda.

 

[ersakthivel]

So stuff like the one above is obviously false propaganda.

 

[methos]

1. Prototypes ( India today )

Oh, so they manufactured brand new Arjun Mk 1 prototypes in 2008... ?

 

[STGN]

https://lh3.googleusercontent.com/-bTYxjnN_Mwo/UPaogo5msWI/AAAAAAAAAAw/egQjKcMZiRA/s640/Arjun.jpg
The shadow of the turret falls on the hull at the third blue line from the top.

it is the place where turret's side wall projection on the hull would fall.

The blue rectangle drawn on the TC's crew hatch cover represent s the true length of the hatch cover .

This rectangle is projected in the correct plane on the hull ,

found out by the downwards projection of the line joining the two hatch covers on the turret top,
to the top of the hull.

This is the perspective drawing as far as I know,

Width over track is 3540 mm.


About half of the crew hatch is enclosed between the red line an the blue line.

The red line indicates the track width border of 3540 mm. Because there needs to be some gap between the inner side of the side skirt and track edges.

That is about 0.50x550 mm=220 mm
3540-(220x2=440 mm)= 3140 mm is the width of the ARJUN turret.

There needs to be a correction factor for taking the same length turret width line which is situated at a depth of the close to 1.5 meter from hull plane . If we apply that the hull width is only going to increase, not decrease.

Because the fixed length rectangle on the hatch cover will measure less length if we bring it in front by 1.5 meters on the hull plane,

Since my opponents here will not accept it as they don't have any idea about Perspective distortion, I haven't included it here.

Even if you take a worst case scenario of 3000 mm turret width, giving a very large margin of 140 mm for inaccuracies

1500mm is the distance between outer most side wall of arjun side turret and the turret center line,
1200 mm is the distance between the two crew hatch centers,
1200/2= 600 mm is the distance of Tc' seat edge from the turret center line,
So 1500 mm-600 mm=900 mm is the space available besides the crew hatch center and the outer most side wall of ARJUN turret,

The composite armor cavity in the photo above confirms that.
http://imageshack.us/a/img585/2162/arjunwieowy.png

Also if you look at the following line drawing posted by PMAITRA the distance between the standing vertical crew hatch cover base and the tip of the gun mantle plate on the turret front is 2500mm.

The roof to vision block over the gunner's main FCS box is situated roundabout at the middle of this 2500 mm distance, that is close to 1300 mm behind the front tip of the gun mantlet plate on the turret front.

SO if you deduct a 700 mm for the main sight cutaway a distance of atleast 600 mm is available as LOS thickness behind the main sight,Even if there is no extra armored block behind the main sight.

But according to the evidence from photographs the inner turret armor wall behind the main sight is bumpy with many folds indicating extra armor support behind the main sight.

And the absence of empty space behind the sloped orange FCS box also indicate there is extra armor behind the main sight.
http://img10.imageshack.us/img10/6488/arjundimensions.png

SO I don't see any need to change my views based on any 3D model provided here.So end of this acrimonious debate must be in sight as there is no possible reason for any poster dispute this measurement.

But okay two claims are made here 1200mm between hatches centers and width of turret 3140mm now lets see what happens when I use these numbers on the same calculations I have made above of the turret roof, granted its not 100% accurate.
If there is 1200mm between hatches then the hatch it self is 49,8cm wide the widest point on the roof is 225,5cm, the overall hull width is 357,6cm and the overall turret width including storage is 275,9cm. so not anywhere near 314cm.
on the other hand maybe erksakthivel made a typing mistake therem and 314cm is the correct width of the turret that means the widest point of the roof is 257,3cm. The distance between hatches is 136,6cm and the hatch itself is 56,7cm. overall width of hull is 406,9cm.
I am left to conclude that the notion of 120cm distance between hatches and 314cm width is an impossibility, not only that, they are both incompatible(8,1% less and 5,3% more off) with known width of hull.
STGN

 

[Kunal Biswas]

Static Show, Genius..

Those Prototypes and Example with there charts are for static show, In special part of factory..

Oh, so they manufactured brand new Arjun Mk 1 prototypes in 2008... ?

 

[ersakthivel]

But okay two claims are made here 1200mm between hatches centers and width of turret 3140mm now lets see what happens when I use these numbers on the same calculations I have made above of the turret roof, granted its not 100% accurate.
If there is 1200mm between hatches then the hatch it self is 49,8cm wide the widest point on the roof is 225,5cm, the overall hull width is 357,6cm and the overall turret width including storage is 275,9cm. so not anywhere near 314cm.
on the other hand maybe erksakthivel made a typing mistake therem and 314cm is the correct width of the turret that means the widest point of the roof is 257,3cm. The distance between hatches is 136,6cm and the hatch itself is 56,7cm. overall width of hull is 406,9cm.
I am left to conclude that the notion of 120cm distance between hatches and 314cm width is an impossibility, not only that, they are both incompatible(8,1% less and 5,3% more off) with known width of hull.
STGN

I did not say 1200 mm is the distance between the hatch centers based on my drawings
.

this 1200 mm measurement was posted by someone else in this thread. my turret width estimation based on the drawing has

nothing to do with 1200 mm figure.

It is dejawolf who posted this 1200 mm figure.Not me.

the drawing explains what I posted, Your explanations can be done with he help of a separate perspective projection.

 

[STGN]

.....

Since my opponents here will not accept it as they don't have any idea about Perspective distortion, I haven't included it here.

If some people say the hatch cover is just 500 mm in width , according to this measurement technique the turret width is only going to increase,

So no can try to wiggle out saying that if the hatch cover width decreases the turret width will also decrease when we go for a staight on hatch cover measurement like the one below.......

Oh its golden comments like this that make my day thank you!
Think about it if the size of the turret get bigger as the hatch size gets smaller then your math. is wrong and your function is not a straight line as size increase or decrease but a hyperbola. This means that you are wrong cause as you get closer to the hatch you will not see the turret shrink just like when you get closer to your computer screen to measure with at ruler, your desk doesn't decrease in size at the same time.
STGN

 

[STGN]

I did not say 1200 mm is the distance between the hatch centers based on my drawings
.

this 1200 mm measurement was posted by someone else in this thread. my turret width estimation based on the drawing has

nothing to do with 1200 mm figure.

It is dejawolf who posted this 1200 mm figure.Not me.

the drawing explains what I posted, Your explanations can be done with he help of a separate perspective projection.

Great if you don't believe its 120cm then why do you write as if it is? Do you have another number for that distance?
And still 314cm overall width is also wrong as I have shown.
STGN
ETA: actually that picture was posted by me and as I have now shown and already said a long time ago its wrong.

 

[militarysta]

It is true only if the roof vision block pipe is positioned vertically , if it is slanted it is not correct. that is why you can not explain the vertical height of the roof vision block in the crew inside photo.

It's vertical - I had explain this hundret times.
And I had explain height vision block inside crew comparmetn too:

see?
internal end of the tureet roof vision block is on the same hight as end of the periscopes for Tc
There is no problem here.

In this photo the top of the orange FCS box is not visible. But the roof vision block opening is visible.You haven't explained it till date.

Again it lies - I had explain this many time. All is visible on other photos -taken from loader site. For example this:

Also according to my measurements the inner armor wall behind the gunner's main vision block is more than 1400 mm behind the tip of the gun mantlet plate on the turret front. But you are consistently maintaining it to be at 1000 mm behind the turret front and erroneously arriving at 330 mm LOS thickness behind the main sight.

But you are wrong, and you can't destroy my mesurments Sorry - you are in big mistake. I pinted this here:

You just can't mark when is ending armour backplate -what is quite funny

My estimate is it is more than 600 , And I explained it countless times.

And you are/where "countless times" wrong. In big mistake.

The roof vision block in LEO-2 is located just 800 mm behind the turret tip.

No it's not:

(scale is given under draw -you can mesure it by yourself, it's part of the offcial manuals whit Leo-2 dimensions)

the roof vision block according to this drawing is between 1300 to 1400 mm behind the turret gun front tip.

I give proper value taken from this draw:

1330mm
Ant it's change nothing

it is located at the back edge of the iron rod like holder , So the roof vision block is close to 1300 mm behind the turret gun front tip.Even if the vision block is vertical (but it looks slanted from all indications)

So if we deduct 700 mm for the main sight cut away a distance of close to 600 mm is available straight away for the LOS behind the main sight.

Sorry but not - all welding lines are visible (end of the main sight "doghouse") and we know inner backplate. It's really easly to masure this distance on photo using those iron bar holder:

See? No magic here -the result is marked on draw whit marked circa about some FCS components.

But in LEO the same distance is less than 1000 mm.

- it's ~1200mm to half of those vision block in roof in Leo-2A4 -do you understand? Not "les then 100" but 1200mm



You made mistake after mistake.

 

[ersakthivel]

Oh its golden comments like this that make my day thank you!
Think about it if the size of the turret get bigger as the hatch size gets smaller then your math. is wrong and your function is not a straight line as size increase or decrease but a hyperbola. This means that you are wrong cause as you get closer to the hatch you will not see the turret shrink just like when you get closer to your computer screen to measure with at ruler, your desk doesn't decrease in size at the same time.
STGN

Your post above has no relation to my drawing.

There was no mathematical function in it.The hatch cover was taken as a basic unit to arrive at the ratio of turret width/hatch cover width .

Thats all.

When I used the hatch cover width of 550 mm in a simple straight forward ratio measurement on turret top, people say No hatch cover measures just 500 mm or even less.

So i used another simple ratio technique in compliance with perspective drawing where for the same hatch cover width of 550 mm I arrived at the same turret width in a deductive measurement method. Both measurement tallies means my measurement technique is correct.

because no one fault the deductive measurement technique i posted . As per this measurement argumentative statements like hatch cover measures less will blow back on the same guy who makes the argument.

So if you have any contradictory viewpoint illustrate it with drawings and measurement on photos. Don't nit pick with trivial statements,

 

[ersakthivel]

Great if you don't believe its 120cm then why do you write as if it is? Do you have another number for that distance?
And still 314cm overall width is also wrong as I have shown.
STGN
ETA: actually that picture was posted by me and as I have now shown and already said a long time ago its wrong.

You are yet to post any detailed drawing based measurement to contradict your own 3.1 meter turret width on pixel based measurement.

 

[ersakthivel]

It's vertical - I had explain this hundret times.

SHOW ME THE PROOF FOR YOUR ABOVE STATEMENT JUST ONE TIME. yOU HAVE NOT DONE THAT.But saying that you have explained it hundred times.

And I had explain height vision block inside crew comparmetn too:

see?
internal end of the tureet roof vision block is on the same hight as end of the periscopes for Tc
There is no problem here.


Again it lies - I had explain this many time. All is visible on other photos -taken from loader site. For example this




But you are wrong, and you can't destroy my mesurments Sorry - you are in big mistake. I pinted this here:

You just can't mark when is ending armour backplate -what is quite funny


And you are/where "countless times" wrong. In big mistake.


No it's not:

(scale is given under draw -you can mesure it by yourself, it's part of the offcial manuals whit Leo-2 dimensions)



I give proper value taken from this draw:

1330mm
Ant it's change nothing


Sorry but not - all welding lines are visible (end of the main sight "doghouse") and we know inner backplate. It's really easly to masure this distance on photo using those iron bar holder:

See? No magic here -the result is marked on draw whit marked circa about some FCS components.


- it's ~1200mm to half of those vision block in roof in Leo-2A4 -do you understand? Not "les then 100" but 1200mm



You made mistake after mistake.

SO AS PER YOUR OWN DRAWING THE ROOF TOP VISION BLOCK IS LOCATED 1500 MM BEHIND THE FRONT TURRET TIP OF THE GUN MANTLET PLATE.

DEDUCT 700 MM FOR THE MAIN SIGHT CUTAWAY.


THE LOS ARMOR THICKNESS BEHIND MAIN SIGHT IN ARJUN IS 800MM ACCORDING TO YOUR OWN MEASUREMENT.

A;SO ACCORDING TO YOUR OWN DRAWING THE THE SAME DISTANCE IN LEO IS 1250 MM.(WHICH HAS O BE CHECKED WITH PHOTOGRAPHS .)

SINCE ARJUN HAS THIS EXTRA 300 MM DISTANCE IN THE DISTANCE BETWEEN GUN MANTLET PLATE TIP AND ROOF TOP VISION BLOCK POSITION THAN LEO,

WHY IT NEEDS ADDITIONAL ARMOR BLOCK OVER GUNNER'S HEAD TO HAVE THE SAME ARMOR PROTECTION BEHIND MAIN SIGHT AS THAT OF LEO?

mark the roof vision block on this line drawing with DIMENSIONS. You will see that the roof vision block is further back on ARJUN than LEO-2. SO no extra armored wall above the gunner's head is needed to arrive at the same LOS thickness.

And you will also know how wrong your so called 350 mm LOS thicness for the ARJUN behind the mainsight statement of your's is.

Please avoid writing I HAVE ALREADY EXPLAINED IT HUNDRED TIMES,. Every one here knows you are yet to explain any thing of significance.it is very irritating to read this YOU DON"T UNDERSTAND, I have ALREADY EXPLAINED IT HUNDRED TIMES spiel of yours again and again.

Why are you shying away from explaining the bumpy folds indicatind variable armor thickness behind the turret front . Do it just one time,not hundred times.

YOUR DOG HOUSE FOR THE MAIN SIGHT IS BIG DOESNOT WASH AS NO ONE KNOWS THE DOGHOUSE DIMENSIONS IN PRODUCTION ARJUN MODELS.

THE PHOTO YOU HAVE POSTED DATES BACK TO 2004 DEFENCE EXPO SHOWING A VERY EARLY PROTOTYPE OF ARJUN.

 

[ersakthivel]

It's vertical - I had explain this hundret times.
And I had explain height vision block inside crew comparmetn too:


internal end of the tureet roof vision block is on the same hight as end of the periscopes for Tc
There is no problem here.


Again it lies - I had explain this many time. All is visible on other photos -taken from loader site. For example this:
ut you are wrong, and you can't destroy my mesurments Sorry - you are in big mistake. I pinted this here:
]


And you are/where "countless times" wrong. In big mistake.


scale is given under draw -you can mesure it by yourself, it's part of the offcial manuals whit Leo-2 dimensions)



I give proper value taken from this draw:

1330mm
Ant it's change nothing


Sorry but not - all welding lines are visible (end of the main sight "doghouse") and we know inner backplate. It's really easly to masure this distance on photo using those iron bar holder:

See? No magic here -the result is marked on draw whit marked circa about some FCS components.


- it's ~1200mm to half of those vision block in roof in Leo-2A4 -do you understand? Not "les then 100" but 1200mm



You made mistake after mistake.

The gunner and the Tc are positioned at 300 mm in front of where they actually are to suit the peculiar needs of the poster to arrive at a lesser LOS of 350 mm behind the main sight.

I have already explained it a thousand times.

The image above is the proof of that.The Tc's seat back is in line with the vertical standing crew hatch cover, which is 2500 mm behind the turret front gun tip according to the image below,

So if the poster makes the needed changes in his draw by pushing the gunner and the Tc 300 mm behind as per photographic evidence, he can arrive at a correct LOS behind the main sight.

 

[Kunal Biswas]

Not from the ongoing topic, But pixal measurement was proven wrong by @sayareakd Sir..

When asked about his height, the measurement were given were approx not very accurate and leave the precision out of the game..

contradict your own 3.1 meter turret width on pixel based measurement.

 

[STGN]

Your post above has no relation to my drawing.

There was no mathematical function in it.The hatch cover was taken as a basic unit to arrive at the ratio of turret width/hatch cover width .

Thats all.

When I used the hatch cover width of 550 mm in a simple straight forward ratio measurement on turret top, people say No hatch cover measures just 500 mm or even less.

So i used another simple ratio technique in compliance with perspective drawing where for the same hatch cover width of 550 mm I arrived at the same turret width in a deductive measurement method. Both measurement tallies means my measurement technique is correct.

because no one fault the deductive measurement technique i posted . As per this measurement argumentative statements like hatch cover measures less will blow back on the same guy who makes the argument.

So if you have any contradictory viewpoint illustrate it with drawings and measurement on photos. Don't nit pick with trivial statements,

I was not commenting on your drawing but on your calculation. Besides I have already made criticisms of that drawing months ago:

But instead of changing the subject lets get back to your calculation which can't be true if it says that as the hatch gets smaller the turret gets larger.

Here is your calculation:
That is about 0.50x550 mm=220 mm
3540-(220x2=440 mm)= 3140 mm is the width of the ARJUN turret.

First problem is this: .5x550mm=225mm (not 220)
So your calculation is 3540-(225x2=450)= 3090

So you function is this 3540-((C/2)x2)=T
T=turret width
C=hatch width
Here is the problem though if we set hatch at 0 width we suddenly have a 354cm wide turret on the other hand if we increase the hatch to 354cm then we suddenly have a huge hatch and no turret. This can''t be true the turret should scale proportionally not disproportionally.

I have to correct my self its not a hyperbola(late night blurriness), its a negative straight line function but this still means that the relation between are is wrong if you scale up the hatch the turret should follow not shrink, the function should be like this
RxC=T
R= size relation between hatch and turret.
using my numbers it would look like this ~5,556xH=T this off cause can't tell us which number is actually the turret width so I need another function: TxH=386,4cm
H= size relation between Turret width and Hull width
Again using my numbers Tx1,29=386,4cm

So I have two functions

5,556xH=T
Tx1,29=386,4cm

H=T/5,556

T=386,4/1,29

T=299,5cm

H=299,5cm/5,556

H=~54cm

This is the essence of the Picture I posted and why your numbers turn out wrong.
STGN

 

[ersakthivel]

I was not commenting on your drawing but on your calculation. Besides I have already made criticisms of that drawing months ago:

But instead of changing the subject lets get back to your calculation which can't be true if it says that as the hatch gets smaller the turret gets larger.

Here is your calculation:
That is about 0.50x550 mm=220 mm
3540-(220x2=440 mm)= 3140 mm is the width of the ARJUN turret.

First problem is this: .5x550mm=225mm (not 220)
So your calculation is 3540-(225x2=450)= 3090

So you function is this 3540-((C/2)x2)=T
T=turret width
C=hatch width
Here is the problem though if we set hatch at 0 width we suddenly have a 354cm wide turret on the other hand if we increase the hatch to 354cm then we suddenly have a huge hatch and no turret. This can''t be true the turret should scale proportionally not disproportionally.

I have to correct my self its not a hyperbola(late night blurriness), its a negative straight line function but this still means that the relation between are is wrong if you scale up the hatch the turret should follow not shrink, the function should be like this
RxC=T
R= size relation between hatch and turret.
using my numbers it would look like this ~5,556xH=T this off cause can't tell us which number is actually the turret width so I need another function: TxH=386,4cm
H= size relation between Turret width and Hull width
Again using my numbers Tx1,29=386,4cm

So I have two functions

5,556xH=T
Tx1,29=386,4cm

H=T/5,556

T=386,4/1,29

T=299,5cm

H=299,5cm/5,556

H=~54cm

This is the essence of the Picture I posted and why your numbers turn out wrong.
STGN

Once again I never said that turret width gets higher when hatch gets smaller.

What I said was if I arrive at 3100 mm width in a straight on by the following formula of

turret width in the picture (in mm) / hatch width in picture (in mm) multiplied by 550 mm(hatch cover width)

and if this measurement is contested by saying the hatch measures just 500 mm, contrary to truth,

then i can use the method explained in the post to disprove them.

because that perspective projection technique will show a much higher turret width if a wrongly applied smaller hatch cover width was used.

But what is amusing is you are simply misquoting me obsessively.

Regarding the doubts you raised on the drawings,

1.what that red line is doing there is to indicate the possible position of the track edges at 3560 mm,

because it is logical in any machine design to extend the hull plate length by a few cms more than the edge of the track width to avoid brushing against the side skirt plates located close by.

If you have any doubt look at the pictures above.

Notice the large gap between the inner side skirts and the track edge.

2.I did not use vertical projection lines just because i fancied it. look at the sharp front edge of the turret , my projection line was parallel to that line of the front corner edge vertical line of the turret. So it is correct.


3. The line across the turret width signifies the plane of the standing vertical hatch cover nothing else.It is this plane that should be projected down on hull for projecting down the rectangle developed from the line across hatch cover to get the true measurement basic principle of perspective drawing as taught in Engineering colleges.It is in fact the cross sectional plane to be precise.

4.The rectangle was developed as a projection from the straight line across the hatch cover and dragged above to show the plane of measuremnet.

So there is no way it can measure 61 pix when the line measures 51 pix.

The difference in measurements (in pix) of two hatch cover shows what role is played by perspective distortion which is heavily discounted by most of the posters contesting my view here.

that is why I insisted on projecting the right length on the right plane instead of unrelated and logically wrong comparison across different planes.


5.The slope of the roof plays no role in projecting the plane view of the turret top on the hull.