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After 23 days of drinking booze and random disappearing, judges finally picked winners of this competition!      In a 45 ton category we came to the conclusion that a member of this forum, w

Backstory (skip if you don't like alternate history junk)   The year is 2239. It has been roughly 210 years since the world was engulfed in nuclear war. Following the war, the United States

Best oscillating turret...

living on the edge:
LwlF4Lo.png
I ended up tightening up the wheels and springs, which as this is a lighter vehicle than the Merkava and M60 (springs and wheels respectively) shouldn't be a problem.
Tracks are 550mm wide, and the contact length 4375mm. the specs resulting from this will be calculated when I have a more accurate mass estimate.
But for now, the track-center-pitch-to-length ratio is 1.63, the contact area 4.81 sq. m, and with 6 wheels per side the MMP won't be too high.
@LostCosmonaut how "hard" a limit is the width requirement- can I have components fold out the way to fit?

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My skills in CAD are way too rusty to participate but wouldn't it be a good idea if all of you could agree on a standard mannequin (a file designed by the organisator or a judge) to check for crew ergonomics (or at the very least if the crew can actually fit inside)?

Just throwing the idea since I though it could be one more factor to differentiate the various designs you came up with.

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13 minutes ago, N-L-M said:

living on the edge:
LwlF4Lo.png
I ended up tightening up the wheels and springs, which as this is a lighter vehicle than the Merkava and M60 (springs and wheels respectively) shouldn't be a problem.
Tracks are 550mm wide, and the contact length 4375mm. the specs resulting from this will be calculated when I have a more accurate mass estimate.
But for now, the track-center-pitch-to-length ratio is 1.63, the contact area 4.81 sq. m, and with 6 wheels per side the MMP won't be too high.
@LostCosmonaut how "hard" a limit is the width requirement- can I have components fold out the way to fit?

 

It's a rail transport requirement. I'm demounting my side skirts to fit comfortably, for example.

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Just now, Alzoc said:

My skills in CAD are way too rusty to participate but wouldn't it be a good idea if all of you could agree on a standard mannequin (a file designed by the organisator or a judge) to check for crew ergonomics (or at the very least if the crew can actually fit inside)?

Just throwing the idea since I though it could be one more factor to differentiate the various designs you came up with.

 

Yes that does sound like a decent idea, though maybe for next time at this point.

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1 minute ago, N-L-M said:

No such thing, just start and you'll learn along the way. low-detail is fine, no need to go full autismo.

 

I rather mean that I haven't practiced in a long time and that it would be very time consuming.

Time that I don't really have now because of work.

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5 minutes ago, Alzoc said:

 

I rather mean that I haven't practiced in a long time and that it would be very time consuming.

Time that I don't really have now because of work.

 

Ahh, I was gonna say “I haven’t used any type of CAD in over 3 years”, but the work thing I get. Classes are starting next week for me, so hopefully I can get most of my vehicle done before then. 

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1 hour ago, Alzoc said:

My skills in CAD are way too rusty to participate but wouldn't it be a good idea if all of you could agree on a standard mannequin (a file designed by the organisator or a judge) to check for crew ergonomics (or at the very least if the crew can actually fit inside)?

Just throwing the idea since I though it could be one more factor to differentiate the various designs you came up with.

I use the standard sketchup mannequins, which are a bit janky and oversized but useful.

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I present to you, the 94/74mm C2 squeezebore anti-tank gun: 

 

Spoiler

gdkzm0G.png

TZcZ8rI.png

AcwJhXZ.png

GynNYUJ.png

6vhNlfl.png

 

currently, the sliding breach and mount are not made. 

 

Recoil stroke: 300mm 

Barrel length: 3.76m (L/40 if using the 94mm as reference, it's an L/50.8 using the 74mm reference) 

Mass: 833.5kg (using steel alloy 7.73 g/cm3

 

Only the first 10 calibers are rifled (940mm), the rest is smoothbore (I hope this is acceptable, it is very similar to the 7,5cm PaK 41 I'm basing this off) 

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Turret details are now in.
b0qByrn.png
The turret and hull were slightly enlarged to improve ergonomics, the tank looks a bit strange now.
The depicted optics are a bit of a "how much optic can I stuff in here anyway" sort of deal, I'm not sure it's even possible to make the rangefinder in the cupola work. But the idea is that when IR optics become a thing they can be seamlessly integrated. Also the gunner's line of sight is stabilized in elevation (by the magic of mirrors and electric servos), the gun drive (hydraulic) is slaved to follow it. This allows good LoS stabilization, and firing on the move can be regulated by the difference between LoS and gun (MG only, main gun from short stop).
Next up on the agenda:
-Sideskirts
-Hull armor improvements
-Sponson goodies
-driver's hatch
-hull interior details.
It may however be a while until my next post.

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Still messing around in solidworks, mass is a little over 8t if I've got it all scaled right.  I jerry-rigged the side hull on and did some other stuff in ways that probably weren't quite right.

SE91rsL.png

 

 

Also realized that despite thinking of stuff like the M47, T23, T-55 and stuff in mind when making the turret, it sure does look a lot like the Chaffee's now that I've refined the shape and flattened it some.

pucBtZR.png

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I'm really happy :) Got the turret pretty far, as well as the gun mount (no breach block yet), AND I decided on the name. May I present to you, the Cascadia Medium Tank T9 ('s turret): 

 

 

Spoiler

miLztya.png

cS4el5R.png

3O6TUmA.png

rDypjmd.png

 

Yes, it is a cleft turret. I was originally going for a Object 477 design, but it ended up being more like a squished Leclerc. I'm quite pleased with it, though. 

 

General: 

Height: 517.6mm (from hull roof to top of gun mount) / 467.5mm (from hull roof to turret roof)

Width: 2.3m 

Length: 3.1m (from turret front to turret rear) / 6.31m (from gun tip to turret rear) 

Mass: 6.86 metric tons 

contains 3 crew (commander, gunner, loader) 

Gun depression: -20* (probably gonna be less due to the hull roof, but still pretty good) 

Gun elevation: +60* (it could go higher, I calculated that it would hit the floor of the hull just past this angle, 62.4* IIRC)

 

Spoiler

6fC7luI.png

kmmeNBL.png

 

Armor: 

Front plate: 230mm

Front sides: 130mm 

Rear sides: 90mm 

Rear plate: 90mm 

Roof: 40mm 

 

Gun mount front: 100mm 

Gun mount sides: 35mm 

Gun mount roof: 25mm 

 

 

The gun mount almost completely surrounds the breach, and acts as a counter balance to assist the stabilizer. I'll post the pics of the gun mount separately here: 

 

Spoiler

pNgDrJt.png

TBOM49u.png

RRQTc5K.png

GZUfCcz.png

ZBmEUnM.png

 

Thankfully, I managed to get the center of mass really close to the center of the trunnion (it is within the trunnion's area), so the primitive stabilizers the T9 has wont need to work so hard. 

 

There's some things I need to change with the turret and mount, mostly just cutting a hole through both so the loader can access the breach easier. Also gonna add commander cupola/MG as well as loader MG and assorted sights, but that's for tomorrow. 

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Finally got my turret to work (decent depression, close to balanced, gun doesn't smash the commander in the groin when it fires);

 

VvHFmvx.png

 

Maximum gun depression is about 9.5 degrees. Model is still a bit unfinished, but it's at least enough to prove the bits work.

 

Weight of the turret and hull armor (ignoring gun model) is about 14.5 tons. Assuming the armor mass increases to 15 tons by the time I'm finished modeling everything, and the armor comes out to 43% of the total mass (midpoint of the range listed in this post; http://sturgeonshouse.ipbhost.com/topic/1085-design-contest-supplement-typical-weights-in-a-modern-tank/     ), it's on pace to come out at about 35 tons.

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5 hours ago, LostCosmonaut said:

Finally got my turret to work (decent depression, close to balanced, gun doesn't smash the commander in the groin when it fires);

 

VvHFmvx.png

 

Maximum gun depression is about 9.5 degrees. Model is still a bit unfinished, but it's at least enough to prove the bits work.

 

Weight of the turret and hull armor (ignoring gun model) is about 14.5 tons. Assuming the armor mass increases to 15 tons by the time I'm finished modeling everything, and the armor comes out to 43% of the total mass (midpoint of the range listed in this post; http://sturgeonshouse.ipbhost.com/topic/1085-design-contest-supplement-typical-weights-in-a-modern-tank/     ), it's on pace to come out at about 35 tons.

 

Loader's position:

Westminster_Knight.jpg

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8 hours ago, Lord_James said:

/.../

Thankfully, I managed to get the center of mass really close to the center of the trunnion (it is within the trunnion's area), so the primitive stabilizers the T9 has wont need to work so hard. 

/.../

Did you tried to look at center of mass with round inserted? I guess balance will become even better with loaded gun.

 

@LostCosmonaut

Are mechanical assisted loading mechanisms/mechanised ammoracks a thing in this universe?

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