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Tuesday, October 20th 2009, 1:41pm

Tanksharp comments

Quoted

Originally posted by thesmilingassassin
As for the KV clone there is absolutely zero SATSUMA design influence involved, period. Its more a Russian design than anything, its merely picked up a few traits from other designs as a result of FAR's Transall venture. Sloped armour and nation specific weapons.
My main mistake with that design was trusting Tank sharp and not seriously studying the stats on the sheet, partly due to my lack of knowledge on transmission weights ect. Hrolfs helped in that reguard and I owe him many thanks. (looks like I'll have to place some more orders from Germany to compensate him!)


Heh.

There are a number of gotchas in TS that can reach out and mess a design up.

1 - There's a number of places where the formulas used just aren't right (this is more a problem in 0.71 than in 0.6, from my experience). I've fixed these wherever I've found them, and anyone who wants a copy of my updated sheet just PM me with your e-mail and I'll send it.

2 - There are a few cases (like transmissions) where you can enter a number that looks good on one page but not so good on another. My practice there is that it's better to be too big than too small: a transmission that breaks down because it's being asked to handle too much power isn't very useful, even if it's big enough to handle the vehicle weight.

3 - Use reasonable angles for armor. Different sources quote different slopes for armor on vehicles, you really have to look at pictures sometimes to see if that number is an angle from the horizontal or an angle from vertical. TS assumes it's an angle from vertical: ie, 40 degrees is a much steeper slope than 10 degrees, and 80 degrees is VERY, VERY steep.

4 - Check your widths: the diameter of your turret ring shouldn't exceed the hull top width (that's the hull width at the deck after the angle of the sides is considered), and the width of your turret probably shouldn't exceed that either (unless you WANT a turret that overhangs the treads while the turret is facing forwards).

5 - Check the internal volumes: at the bottom of the hull and turret design sheets, there's a set of numbers that show how much volume is left over in the hull and turret. TS seems to drastically underestimate the amount of space engines/transmissions/suspensions/etc take up, so this number won't normally be a problem for you in the hull. In the turret, though, this is where you'll see things get cramped real fast.

6 - Ground pressure: the WW Dutch and the OTL Russians are big fans of keeping this low, but it COSTS in terms of weight from the wide tracks and road wheels needed. Don't let it get too high, though, or you risk ending up with a vehicle that spends a lot of it's time getting dug out after a soaking rain.

7 - TS won't really alert you to many of these: unlike SS it doesn't throw up a warning anywhere, you have to go look at the available internal volume (as an example).

2

Tuesday, October 20th 2009, 2:10pm

Excellent post Hrolf. Many thanks.

Kaiser Kirk

Lightbringer and former European Imperialist

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3

Wednesday, October 21st 2009, 3:29am

Yep, well done Hrolf.

What I remember from trying to come up with “reasonable” parameters for the LT-35 was not just should the turret ring not be bigger than the hull, it shouldn't even be quite equal. Looking at my tank I have the upper hull width at 90%, and it's 60% of hull width. The latter seems the more familiar ratio.

And yes, low ground pressure is an “expensive” as a luxury. Drives track weight up, performance down. So tempting to ditch it but I have so much soft terrain.

Some samples I accumulated while researching the LT-35. Since weight tended to rise, PSI numbers are model specific, but I didn't bother to include the gun size (off to Wiki....) or tank model in my notes.

Of course, can find a wide range of conflicting info on the web, but it should give an idea of the ranges. I had more info, but seem to have tossed it.

Tiger E : 183cm turret ring, 3 man turret
88mm gun

M3 Stuart : 118.7cm turret ring 2 man turret
10.8psi 37mm gun

M22 Locust : 120cm turret ring 2 man turret
7.1 psi 37mm gun

M3 Lee : 138cm 3 man turret
12.6 Psi 37mm turret (75mm gun in hull)

M24 Chaffee : 185cm turret ring 3man turret
9.6psi ...16” wide treads, issued 75mm upgunned to 90mm

M4 sherman : 175cm turret ring 3man turret
13.7psi issued 75mm upgunned to 76.2mm, efforts to upgun to 90mm were apparently problematic, though the derivitive M36 TD had a 90mm.

Panzer Mk IV : 160cm turret ring 3 man turret
9.8 psi issued 75L24 upgunned 75L48

Panther : 165cm turret ring. 3 man turret
13psi 75L70.

Anyhow, the more powerful the gun, the bigger the turret ring, and the wider the tank hull needs to be.

4

Wednesday, October 21st 2009, 3:32am

Where can you download tanksharp? I can't find it using google.

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Wednesday, October 21st 2009, 3:36am

Hmm, the M4 was actually upgraded to a 105mm cannon by the Israelis (M-51 Isherman) and had a 105mm Howitzer as a support tank in US service

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Wednesday, October 21st 2009, 3:38am

TankSharp can be found here:
http://www.stardestroyer.net/Armour/Shep…/Tanksharp.html

Yes, the Sherman was upgunned to a 105mm gun, but that was well after WWII. The 105mm howitzer had a good deal less recoil than the 90mm gun had.

7

Wednesday, October 21st 2009, 4:24am

The file says its corrupt when I open it. Am I doing something wrong?

This post has been edited 1 times, last edit by "TexanCowboy" (Oct 21st 2009, 4:26am)


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Wednesday, October 21st 2009, 1:21pm

Click on the link, don't try to open it, there's a link to a file behind that link (there are links to both the 0.6 and 0.71 versions of TankSharp). I had no problems downloading and opening the 0.71 version from that site.

Kaiser Kirk

Lightbringer and former European Imperialist

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9

Thursday, October 22nd 2009, 5:49am

Quoted

Originally posted by Vukovlad
Hmm, the M4 was actually upgraded to a 105mm cannon by the Israelis (M-51 Isherman) and had a 105mm Howitzer as a support tank in US service



Correct, but they did have to modify the turret to do so including adding a counterweight out back. This was one of the problems they seem to have faced with the 90mm as well. Further, the early efforts wound up overstressing the suspension, so they had to redo that as well. Doing more digging I found an article online regarding Israeli Shermans, and it confirmed that the 105 relied on HEAT rounds.

Mounting a larger bore weapon with similar or less overall recoil and energy is far less problematic. The Sentinel was used as a test bed, and could use the 57mm 6pdr ATG, and the 87mm 25pdr Gun/How (though the turret volume consumed was an issue) but seems to have been less than satisfactory with the 17pdr.. which was a more powerful piece than the 87mm.

Quoted


When the M-50 designed to defeat T-34 and T-85 tanks with the CN 75-50 gun, with appearance of T-54 and T-55 the new Arab tanks Israeli needed again new gun and as on M-50 Israel used French gun, the new 105mm CN 105 F1 gun. This gun was a 56 calibre and 6m long, firing a HEAT round with a 1000 m/sec. However, this gun could definitely not be installed in a Sherman turret, as this offered not enough recoil space. Israel then came up with a solution of their own: By shortening the gun to a 44 calibre gun (about 1.4 meters shorter) and accepting a lower muzzle velocity of around 800 m/sec. this odification, called the CN 105 D1 gun, could indeed be crammed into a T 23 turret.

This post has been edited 1 times, last edit by "Kaiser Kirk" (Oct 22nd 2009, 5:51am)