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Tiger I
Sept 5, 2013 19:01:32 GMT -5
Post by bobw on Sept 5, 2013 19:01:32 GMT -5
Hey, spawnkill. I used a slightly modified method for the hull of what my adviser used for his. I built the "skin" out of 3/4" ACX plywood first. It is easy to work with, costs an average amount, and is very weatherproof, and won't have any buckling to it due to welding and such. Once the ACX is formed, I used angle iron inside to outlines all the edges and corners. So, I use the skin as a guide for building the frame. Now, I made my plywood fit together only with dowel rods to each other, so I can put it together and take it apart over and over again in case I need to get at the frame from a different angle. My frame also bolts to the skin since my scale tank was put together with bolts in real life. I will eventually put the final bolts on and glue all the plywood joins to each other. The 40% Tiger tank pictured up a few posts looks like its skin was chipboard if you see it earlier on in its life. I just went with what my adviser did as I could see his example in real life.
Th commercial treads, unless from an excavator or something bigger than a skidsteer may not be long enough for a 75% Tiger. I know that one day you might look at the Tiger dimensions in 75% scale and decide that some of the dimensions might be adjusted to make it more buildable. It is all a "compromise in motion" I have found. Designing the treads might be difficult depending on your level of compromise. The 3-man paintball Tiger went very simple, which is one very goo choice. My treads are going to be more complex since I am staying very close to scale looks. There are so many ways to build the tracks - I love the looks of the ones on the 40% Tiger - just conveyer belt and rectangular tube - easy to compute steel cost for that one with a little adding and multiplying.
Hydraulics, you have to make room for the oil reservoir, maybe 30+ gallons, and watch out for hoses not to get cut and spray anyone. My hydraulic skidsteer, a New Holland LX865, has 63 HP with no tracks and will almost bog completely down doing a zero-turn in soft dirt. It weighs 6,000+ pounds, which a 75% Tiger would be challenged to weigh less than.
More later.
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Tiger I
Sept 5, 2013 19:38:09 GMT -5
Post by bobw on Sept 5, 2013 19:38:09 GMT -5
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Tiger I
Sept 5, 2013 21:40:34 GMT -5
Post by SSBlackangel on Sept 5, 2013 21:40:34 GMT -5
here is the equation you are looking for "K.I.S.S" Aka Keep it simple stupid.there is no need to reinvent the wheel or the track i should say. depending on how big this thing is you have pleanty of good reliable options. If you are going big the .75 tiger design cant be beat. it has very strong,economical and easy to work with drivetrain. 1st thing you need to do is get a model of the tiger. you cant make a realistic tank without anything to scale off of. just get a forces of valor 1/32 scale they are about $60.Already built and ready to sit on your shelf.
youtube has a ton of the builds from scaledtanks.com look at the sherman or leopard 2 for examples
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Tiger I
Sept 5, 2013 21:43:44 GMT -5
Post by SSBlackangel on Sept 5, 2013 21:43:44 GMT -5
why bother with the hydraulics? just use the t20 tranny from borg warner. that what i'm using and ive been planning this build since 2005. they are only about $1300 rebuilt from route 6x6. pick up a briggs and stratton 24 hp and you will have more power than you know what to do with as long as it doesnt weigh too much
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Tiger I
Sept 6, 2013 5:47:02 GMT -5
Post by bobw on Sept 6, 2013 5:47:02 GMT -5
Thought 1) Here is my caveman math - the Tiger is about 21 by 12 by 10 feet (not including gun length in there). At 75%, that is 1080 cubic feet. My tankette at 8.5 by 6 by 4 at full scale is 204 cubic feet. My tank will probably weigh 1300 pounds with a strong structure. Assuming that strength/weight scales up, I would estimate that an 1080 cubic foot structure would need to weigh the same number of pounds per cubic foot as my tank to be as strong. So 1080 / 204 = 5.3 times the weight of my tank, which is 1300 * 5.3 = 6890 pounds, or 3.5 tons, about the weight of a skidsteer. I made a math error when I got my ballpark estimate of 12,000 pounds in the earlier post. I have seen a fellow's pictures who started out with the idea of a 75% Panther. He built a very simple outline of the hull from 2x4's just to see what it would look like, and it looked mighty big to me.
Thought 2) You could think that the 75% tiger would be around 16 feet long (sounds about like a car or truck length), 9 feet wide, and 7.5 feet tall - sounds just a bit bigger than a truck in both those dimensions, so you would think that it is truck sized, so should weigh a bit more than a truck, which is much much less than 6890 pounds.
I have an easier time with Thought#1 because I have been playing with these steel pieces getting a feel for how strong/flimsy is each thickness and shape of steel and how stiff is the frame when I lift one corner up. So I figure if something is twice as wide as my hull, then maybe I used 3/16" by 1.5" by 1.5" angle iron, so to double my span with the same strength I would use 3/8" by 3" by 3" angle iron, which would be 8 times the weight. But I could be off. Just a thought.
BTW, I love the T-20 mentioned above. I am using one. They are said to be good up to maybe 100hp. My impression of a 75% Tiger is that it would need 50hp or more, based on general skidsteer sizes and weights that I am aware of.
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Tiger I
Sept 6, 2013 20:01:33 GMT -5
Post by spawnkill on Sept 6, 2013 20:01:33 GMT -5
SSBlackangel I love the video definitely inspiring. The T20 trans was one of the first trans that we ever used. I don't know if you remember the tank at Vermont but that was a build from me and toxin that didn't last one game. John ended up taking over the project and we haven't heard about it since but that had a T20 trans in it. I agree with bobw that It'll have to be at bare minimum 60hp. According to my notes a Chevy S10 runs at about 105hp for a 4 cylinder which is what we have. so maybe 50hp will be acceptable. hydraulics will give us more torque than we'll know what to do with but won't give us the speed, which is acceptable. I can only assume that if I get a smaller engine, (@60hp) the only way I'll achieve the torque that I need would be through gearing. Same thing according to my notes a stock S10, 4 cylinder, has 135 ft. lbs. @ 3200 RPM. What I don't know is if that is just straight engine or with the trans as well. My source for this info was from Wikipedia by the way. On a side note I was not able to save ANY money today. My fiancé went to Virginia to go to a friends wedding and her car broke down. $400 later out of my money she got it fixed but left me with nothing. $6 to be exact so I'll have to wait until next paycheck to start saving for the build.
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Tiger I
Sept 10, 2013 13:20:08 GMT -5
Post by SSBlackangel on Sept 10, 2013 13:20:08 GMT -5
yeah i remmember the 6x6 toxxin had. no idea what happened to it.Idk if john still has it. Haven't spoken to him in ages
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Tiger I
Mar 5, 2014 22:49:48 GMT -5
Post by hardboy on Mar 5, 2014 22:49:48 GMT -5
any updates?
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Tiger I
Mar 9, 2014 23:43:25 GMT -5
Post by spawnkill on Mar 9, 2014 23:43:25 GMT -5
Not really. Things have been crazy for me lately. I'm just starting to get back on my feet. But I'll be around for Stalingrad with my crew at the ready looking like a total of 8/+ including me and Toxin.
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Tiger I
Mar 9, 2014 23:44:07 GMT -5
Post by spawnkill on Mar 9, 2014 23:44:07 GMT -5
I give it a month more max before I start trying to save for this build again.
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Tiger I
Mar 11, 2014 23:00:49 GMT -5
Post by hardboy on Mar 11, 2014 23:00:49 GMT -5
Keep on it.
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