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M4 Sherman Crab tank (RC)
My latest model, 2 months of work is finally complete.
About this creation
Video of it in action here

Design of model


This vehicle has been a dream of mine to replicate a M4 Sherman ever since I began building tanks. There was a lot of planning over the past year to the design of this, there are different components from other tanks of mine that I combined to build a ultimate version of a Sherman. There is little space left inside, as the transmission, electronic clutch braking mechanism, and flail components take up all of the lower hull space, there was little space for the turret's mechanisms to be routed into it. The gun's elevation is controlled by a mini linear actuator that is located below the turntable and rests on top of the mechanism that shifts the gears for the transmission, and elevates/depresses the flail.

The first Sherman I built was my 3rd tank of a larger scale, it was designed to replicate a British version of the Sherman, the Sherman Firefly. It was flawed in several locations, but I wasn't pleased with certain components of it, the suspension was inaccurate for the early version of the Sherman, as it uses VVSS(vertical volute spring suspension). My model had HVSS (horizontal volute spring suspension), this version of suspension is only used on later variants of the M4A3E8 Sherman(vehicle used in Fury). I attempted to build another version of a Sherman in the fall of last year, but it suffered from the same issue, the suspension was incorrect in size, I decided to scrap the project and build other vehicles instead until I found a better, more accurate solution. I decided to use the Torsion bars from the Hetzer, as it would provide the proper angle for the suspension swing arms, and be low profile, so the hull could mount the Transmission from my Tiger I.

The transmission takes up nearly the entire 3/4 of the lower hull of the vehicle, it fits between 10 studs of free space, and has 2 gear ratios, a 1:2084, and a 1:1.3474. The remaining space of the lower hull is taken up by the electronic clutch braking mechanism (this creates the effect of the real steering mechanism of the M4 Sherman, to steer one track's power is diverted to the other track, and the unpowered track is braked). The space behind that is for the 8878 rechargeable battery.

Another complex component for the Sherman is the turret and the transmission housing cover, these pieces have a complex shape to them, and are both round. The transmission housing cover is situated at the front of the vehicle, where the final drives interface with the transmission. It took 5 revisions of it to cover the knob gears behind it, and retain the proper shape. The turret was difficult too, but I broke it up into 4 different shapes that could be replicated in bricks and be combined to produce the proper round shape. Those components being the sides, top, mantlet, and rear bustle. The sides and bustle were the most difficult to replicate, as the bustle has a complex protrusion off of the back of the turret that is used to house the radio. The sides were difficult as they had to slope upwards to to roof of the turret.

The current model isn't entirely perfect, the major imperfections being the height of the center portion of the hull, and turret size. The hull is 2 studs too tall, as it needs to mount the flail's L motor for power, and the main axle that powers the flail's Linear actuators has to have a directional change. The turret is slightly too tall, but this was to compensate for the height of the hull, it looked too small, and the mini linear actuator made it taller. If a standard version of a M4 Sherman would be built, it wouldn't have these issues, because of the internals, though I am pleased with how it looks, it could still be improved.

History

The Sherman crab was designed to clear minefields the Allies would encounter during the Normandy landings, there are several other Flail vehicles used too, but I chose the Sherman variant.I will spare the remaining bits, as this post is getting long, more information here if anyone is interested in the history of it.


For some reason Java won't allow me to certify this site, as I have tried several times to paste the uploader address in security to certify it, but it doesn't work and Mocpages won't allow me to embed videos, as it doesn't allow Iframes. So I have to manually type the HTML, only a couple photos will be posted, the video covers a lot more, and I can link the photo album to Flickr.








As some may know I am off to college in a couple weeks, so this will mean that this is my last model for a long time, possibly until next summer.



Comments

 I made it 
  August 12, 2015
Quoting Kermunklin the Giant Evil House Head The technical stuff is a bit beyond me, but that tank is super awesome! Off to college you say...studying engineering by any chance?
Yeah, I am thinking about it, but I am not 100% sure yet.
 I like it 
  August 8, 2015
Very good!!!
Tommy Styrvoky
Matt Bace
  August 6, 2015
An incredible work of engineering, and one of the best PF tanks I've ever seen. The mine flail is a really neat feature and it works flawlessly.
 I like it 
  August 6, 2015
Hello Tommy. Simply an amazing design and build of this flail variant of the Sherman. The complexity and how you got it in the build is just mind boggling. Top points for the detail and especially the video on the Flickr page showing the flail in action.
 I like it 
  August 6, 2015
The technical stuff is a bit beyond me, but that tank is super awesome! Off to college you say...studying engineering by any chance?
 I like it 
  August 6, 2015
A military masterpiece of design, engineering, detail, and function. Absolutely flawless. BOAJEWD.
 I like it 
  August 6, 2015
Excellent, one of your best so far... have fun at college, im in college at the moment to, which is why im building slower than before... college is fun man, nothing like public school, not nearly as much pressure for popularity and such, because you're all there to learn...
 I like it 
  August 6, 2015
Engineering, yeah!
 
By Tommy Styrvoky
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LEGO models my own creation MOCpages toys shop M4 Sherman Crab tank (RC)Historic military


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