My Senior design project - a "Swamp Thing" tracked vehicle clone

   #1  

Garauld

Silver Member
Joined
Feb 15, 2014
Messages
231
Location
Binghamton, NY
Tractor
Deere 265, Kubota KX41-3V
Hello all, I am a retired mechanical engineer having stopped looking for a regular job for about three years now. I have been looking to keep my gray matter busy other than working on the regular upkeep jobs around the house. I like to tinker, design and build things; I have a fairly complete machine and fabrication shop at home and am well versed in the use of various computer programs including 2D and 3D CAD. Some time ago, I came across the Youtube video of a tracked vehicle called "Swamp Thing" which was built by an individual named Tom Zervas in Saginaw, MN sometime around 2011. Here's a photo of it and you can see his video here:

Swamp thing.jpg

Swamp Thing by Zervas - STZ Custom Track Vehicle - YouTube

This design interested me and I tried to find out more about it. Unfortunately, Tom Zervas died last year (2017) and the youtube video is all I could find on this machine. Being an engineer, I decided to design and build one on my own. I researched a bunch of threads on this site and more than a few others, and watched a bunch of videos as well. I planned to use a Geo metro engine or similar, but recently came across a cheap Toyota Echo due to it being crashed and totaled. I plan to use that engine and auto transmission. I will use differential brake steering and build my own tracks from conveyor belting and steel channel sections. I spent a few months modeling up various configurations and the following is my current design. Any comments or suggestions are certainly appreciated. I plan to regularly post new photos of the parts I make and keep this thread running while I progress it thru the build and hopefully, testing process. Let's have some fun and a few beers doing it!

QLaYDoC.jpg
 
   #2  

bcp

Super Star Member
Joined
Jul 8, 2009
Messages
11,412
Location
SW WA
Tractor
Kubota BX2360
Welcome to TBN.

Make it float, too. :)

Bruce
 
   #3  

airbiscuit

Elite Member
Joined
Aug 28, 2004
Messages
4,199
Location
NW Wisconsin
Tractor
New Holland T2310, Kubota L3010 GST, New Holland TC21DA, Farmall H *** Previously - 1941 John Deere B, Shibaura SD1500, John Deere 850, Bobcat 642, New Holland 1925
I've seen vids of people who have cut most of the sidewalls off tractor tires and used them for tracks - driven by rubber tires. It looked pretty slick and easy.
 
   #4  

CalG

Elite Member
Joined
Sep 29, 2011
Messages
3,873
Location
vermont
Tractor
Hurlimann 435, Fordson E27n, Bolens HT-23, Kubota B7200
   #8  

Groo

Platinum Member
Joined
Nov 5, 2008
Messages
805
I'd probably stick with heavy duty comercial ZTR hydrostatic system.

I'd spend my engineering time on a better suspesion and maybe water drive system.
 
  
  • Thread Starter
#9  
OP
Garauld

Garauld

Silver Member
Joined
Feb 15, 2014
Messages
231
Location
Binghamton, NY
Tractor
Deere 265, Kubota KX41-3V
OK, I got the engine out of the damaged Toyota Echo. It is 1.5L fwd car rated at 108 hp and 103 ft-#. Yes, I know it is a bit strong but I was having trouble finding a Geo Metro 3-cyl engine. These Echos are plentiful and I thought it may be possible to detune it by disabling a cylinder or pulling a NASCAR trick of adding an intake restrictor plate. Anyone else have a better idea?
DSC00826.JPG
I plan to swivel the normally transverse engine around so the axles point front to back. This engine has an open differential which will allow me to lock the axle pointing aft by bolting it to the frame. The forward axle will then be connected to the drive differential up front for driving the tracks. For the drive differential, I bought a rear differential from a 2000 Toyota Rav4 which is also an open diff. In case you don't know what an open differential is, it does not contain any limited slip type devices. The Rav4 diff I bought has a decently tall ratio of 2.93. I calculated the top speed of my snowcat (which I have named "Snowzer") to be about 20 mph with the engine spinning 6000 rpm. I plan to use the CV joints from the Echo to fabricate a driveshaft to connect the engine to the drive diff. An Echo wheel hub flange will be machined to bolt to the drive diff input shaft which also has a flange. I'll have pics later in the project. Here's some of the parts I scavenged from the Echo before the carcass was hauled to the scrap yard:
DSC00829.JPG
I've also made up some items primarily consisting of suspension and steering brake components:
DSC00828.JPG
My plans for the following week are to measure up the engine, tranny and radiator parts so I can accurately update the computer models of them. I hope to design up engine mounting brackets too.
 
Last edited:
   #10  

MossRoad

Epic Contributor
Joined
Aug 31, 2001
Messages
49,456
Location
South Bend, Indiana (near)
Tractor
Power Trac PT425 2001 Model Year
I've never heard of a Toyota Echo. Had to look it up. Is it the same as the Yaris?

Why derate the engine power?
 
 
Top