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Tanks! If is has Tracks it goes here..


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  #1  
Old 09-24-2012, 04:27 AM
Catrik Catrik is offline
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Default Scratchbuild 1/10 KV-2

Hello everyone, I have finally decided to start my first RC project! With no less than 1/10 scale, full metal version of the Soviet KV-2 tank.
I chose the KV-2 because it is mostly flat surfaces so it is easy to make, and - it looks so badass! Some of my ideas:
-hull and turret from 2-3mm sheet metal
-cordless drill motors&gearboxes
-bevel gears from old angle grinders
-12V or 3x 6V (depending on what motors I find) moped batteries
-Tracks from moped chains with metal pads welded on
-sprocket from moped gear
-torsion bar suspension
-working gun with electric firing and recoil system (I hope!)

I don't have any detailed plans. With mostly flat surface and plenty of internal space to put all the stuff in it should be pretty straightforward build, but with experience from other projects I know it wont be The gun will probably be the hardest part, I will try to make the parts from a chunk of steel by hand but if it wont work I'll have to get them machined.

Right now I only have an ugly cardboard model to get a little idea of what Im doing.. looks huge! I hope to get the motors and some angle gears this week to make sure they fit in how I planned them and start working on the hull after that.


Some references I am using:
http://mechcorps.rkka.ru/files/kv2/kv2.htm
http://img390.imageshack.us/img390/2794/kv2draw3kf.gif
http://www.network54.com/Forum/47208...urret+interior
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  #2  
Old 10-12-2012, 05:38 PM
Catrik Catrik is offline
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Default Re: Scratchbuild 1/10 KV-2

I got the project finally started. Hull material is no less than 3mm steel
I made the sides, floor and bottom front armour from a single piece. Sides were bent with an 50 ton jack press with angle tool, front armour with vice.
Im already off the measures, the sides are 5mm too tall and the floor is 10mm too wide.. I would have not expected for the metal to stretch that much from the bending! Im gonna leave it as is but hey, the USSR was not known for their precision engineering anyway
We had some problems (you dont often see 50-ton jack press tools break while building scale model parts) so that's all I managed to do today. Tomorrow I hope to finish the front and rear section to make the hull sturdy enough to start working on the suspension. I have a plan how to do it but I have no idea if it will be strong enough, the model is already around 5-6kg

Oh, and still no motors. I know a place where I can get drill motors but Im gonna finish the suspension first so I will know how much I have space for the motor+tranny.


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  #3  
Old 10-12-2012, 09:24 PM
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doodlebug doodlebug is offline
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Default Re: Scratchbuild 1/10 KV-2

Nice start on the chassis, I like overkill
Cheer's, Neil.
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  #4  
Old 10-13-2012, 04:27 PM
Catrik Catrik is offline
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Default Re: Scratchbuild 1/10 KV-2

I dont like stuff breaking down Even my computer case is made from 2mm steel :P
I was building so intensively I forgot to take any but one picture. You can probably see from my last picture that the hull front side are cut waaay differently.. I have no idea how that happened! I atleast triple checked every measure I fixed that and made the front and rear armour plates but didnt get any welding done since welder was broken. But heres my idea for the suspension:



The black thing is sorta like a zip tie, but made from metal and is used for packing large stuff. Very springy. The left side will be fixed to the hull, right side is in a notch cut in the nut. Bolt will be the pivot point and the metal rod is the suspension arm and so on. Not a very good explanation but that's the general idea hopefully the welder works tomorrow so I can put in all the parts I made today and build one suspension arm so I can test how much force one "spring" has. There are 12 road wheels/springs in total so it should be pretty good.
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  #5  
Old 10-13-2012, 10:49 PM
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Default Re: Scratchbuild 1/10 KV-2

Have you searched for "spring steel"? Not sure if wind up clock spring's are tough enough, but maybe somebody will chime in and help more.
Cheer's, Neil.
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  #6  
Old 10-14-2012, 03:40 AM
Catrik Catrik is offline
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Default Re: Scratchbuild 1/10 KV-2

As far as I know, that is spring steel. If I twist it, it will always go back to straight. if it turns out too weak, I can tape two of them together and have double strenght And I can adjust pre-tension by rotating the nut where the spring attaches.
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  #7  
Old 10-14-2012, 12:57 PM
Catrik Catrik is offline
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Default Re: Scratchbuild 1/10 KV-2

Not much work done today since the welder was not working. I did a lot of planning and some prototype track pads



Looks okay~ish but not realistic at all. Very simple and easy to make, but slow since I will need about 220 pieces of them BUT! Apparently my father-in-law has access to laser cutter! Then I could make them a little more complex. He could cut a lot of other pieces too to make my job easier Roadwheels, sprocets, turret..

But the gun. I started wondering if its gonna be legal at all so I sent email to local police about my plan for the gun. I live in an apartment so I could rarely shoot it anyway. If it turns out illegal as I planned it, ill make it a blank firing gun. Then I could atleast shoot it at father-in-laws backyard.

Last edited by Catrik; 10-21-2012 at 04:29 PM.
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  #8  
Old 10-21-2012, 04:26 PM
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Default Re: Scratchbuild 1/10 KV-2

I have been a little sick so havent done much. The metal band suspnension is not going to work, way too loose stuff. I taped three of them together and one suspension arm bottomed out at around 1.3kg, thats only 16kg for all 12 arms. I could use something like a very large band saw blade, but then there could be space issues.. I think Im gonna use spring steel rods, I have no idea where to get them or what thickness I need but I'll figure that out later. This guy http://youtu.be/Y5tfvQjeOFI has similiar sized and weighed tank and the suspension looks pretty good.

As for electronics.. Drive motors are gonna be MY1016, 24V 350W from a scooter
Sabertooth 2x25 for speed controller
SportBec
DoubleSwitch relay for firing the cannon
+some small geared motors for turret and maybe a dozer blade.

I could use some recommendations for small <1A brushed ESCs and radios with atleast 6 channels. At the moment Im thinking about getting a Turnigy 9X, seems pretty good for the price since I dont need any fancy features.
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  #9  
Old 11-04-2012, 12:51 PM
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Default Re: Scratchbuild 1/10 KV-2

I got the motors and some parts for roadwheels. Not much actual work done.


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  #10  
Old 11-04-2012, 03:42 PM
edwalsh18 edwalsh18 is offline
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Default Re: Scratchbuild 1/10 KV-2

If you want a cheap 2.4ghz tx/rx check out hobbyking. They have a hobbyking brand set for $25.00 not sure what it is in euros. But if u go that route dont forget the cord that goes with it to program it
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  #11  
Old 11-17-2012, 03:25 PM
Catrik Catrik is offline
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Default Re: Scratchbuild 1/10 KV-2

Some updates.. I figured out a pretty easy way to centerline small round pieces. Just put a grid paper under it! The bigger wheel, with six holes, is for the front/tension wheel. I just drilled 10mm holes and used a thing like this to make the shape. What is that called in english? Anyway, I've made two of them. I hope that last two will come out a little better so I will put them on the more visible outer side


I tightened a bolt to a bearing and place it in the bearing house so I can align the housing while I tack it in place.



Also figured out a stupid easy and simple way to mount the suspension rods.
Btw, spring steel wire at Finnish scale model shop = 30 euros per meter. Price at local hardware store = 30 euros per KILO! A little cheaper And they gave me a bunch of different diameters for free to measure what I need. 4 or 4,5mm feels good but I'm starting to think my estimation of 40-50kg is not enough for the complete model..
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  #12  
Old 11-17-2012, 11:42 PM
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Default Re: Scratchbuild 1/10 KV-2

Search for torsion bars with no pre-load. We used them to build custom machines. They twist under load and last forever.

Joe
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  #13  
Old 11-19-2012, 07:11 PM
Catrik Catrik is offline
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Default Re: Scratchbuild 1/10 KV-2

Quote:
Originally Posted by Smokin Joe View Post
Search for torsion bars with no pre-load. We used them to build custom machines. They twist under load and last forever.

Joe
Im not sure what you mean. How is "torsion bar with no pre-load" different from spring steel wire that I have now?
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  #14  
Old 01-14-2013, 01:09 AM
Catrik Catrik is offline
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Default Re: Scratchbuild 1/10 KV-2

Sorry about the missing pictures above, I probably moved them.
I've made all kinds of little progress but I'll let the pictures speak!




Here is a completed road wheel/suspension part


Unrelated, another piece of Soviet engineering I've been working on, Dnepr MT-6 engine:
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  #15  
Old 01-14-2013, 02:52 AM
grumpygrady grumpygrady is offline
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Default Re: Scratchbuild 1/10 KV-2

looking good so far
is the mt-6 a 650cc motor?
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