brice_arnold

My Feedback: (6)

Just from general browsing it looks like most of you guys are into scale tanks. I thought you might get a kick out of this project that I have been working on. It a little outside of the box. I designed this from scratch and machined all of the parts over a three month period. I have been told countless times that it reminds people of the Howe and Howe Ripsaw. I was actually unaware of the Ripsaw until I was well into the project. It is significantly different than the ripsaw in that each track assembly is independently suspended from the chassis. Some stats

1. 62cc two stroke motor with custom made pipe

2. Custom Gearbox with independent/proportional control of left and right tracks from forward to neutral to reverse.

3. 400 man hours of labor

2. 200 machine hours

4. Roughly 600 custom machined parts.

5. 76 pounds of aluminum, plastic, and steel.

Here is the original build thread.

http://www.rcuniverse.com/forum/m_94..._1/key_/tm.htm

Here are some photos from RCX 2010. These were taken by Mark Hull From Team Go Nads

brice_arnold

My Feedback: (6)

Here are some more photos from RCX taken by a forum member that went to the show

brice_arnold

My Feedback: (6)

Here is a teaser video that we took this weekend. I was having some serious radio glitching issues which is why it's so jumpy in the controls. I am switching over from an FM system to a 2.4 GHz DSM system this week.

http://www.youtube.com/watch?v=rANs8Ll0hf4

brice_arnold

My Feedback: (6)

Here is a video of the gear box in action from forward to reverse.

http://www.youtube.com/watch?v=OVRBeCuj4PY

Here are all the parts in the gearbox







This is the input gear/gearbox cover



These are the shifter mechanisms. Basically the shifter is an acme screw that is coupled to a shifting gear. The gear has clutch plates and moves between a forward powered gear and a reverse powered gear.



This is the powered reverse gear assembly





This is the differential assemble that generates forward and reverse gear motion from the input gear.





Here are the output and forward powered gears installed in the case halves



Here is the gearbox almost ready to get bolted together



The shifter assembly installed onto the gearbox



The complete gearbox

googlydoogly

That's damn fine engineering, dude. [sm=thumbup.gif]

pattoncommander

Lots of very fine engineering...nice to have the right tools and shop. All in all, the first photo is the best.[sm=regular_smile.gif]

tankfanatic

Wow, that's is just some insane work!
Agreed, the first photo is the best......no disrespect if she's a loved one.

If she's just a model....then forget the latter! lol

googlydoogly

It's kinda sad I had to scroll back up to see what you guys are talking about. Completely missed her.

shenlonco

My Feedback: (2)

Pretty neat all though i feel the tracks are way to thin and need to be much wider for the size of this thing.

heavyaslead

That is a wonderful project. Looks like the French Char Bis

Let me know when you can make that gearbox and tracks available, it would be great as electric too.

Perry S.

Great machining and design work. I was really excited when I saw the pic's but the video disappointed me. It looks like it has little power, unable to tun in the grass or even climb into the grass at one point. I thought it would be rippin the place up instead of fizzling out.

Maybe it does a lot better but you just haven't posted those videos yet. Nice engineering though.

Perry

thebronze

Very Kool.....

(more pics of the girl)....LOL

Panther F

Looks great! So out of curiosity, a projected final cost? And they thought Tamiya tanks are expensive!


- Jeff

brice_arnold

My Feedback: (6)

This was a combination of the crappy radio set-up and the wearing of the gearbox. The motor is plenty capable of pulling this tank. These motors have been used on go-peds to get a +200 lb man up to 60 mph. They shouldn't have any problems with the tank. If you watch the video closely you can see that all of the servos were moving erratically and I never had good control of the tank. This was due to rf noise coming from the engine and the cheap receiver I was using which was susceptible to noise. The other issue was in the wear of the gearbox. The gearbox uses several clutches which rely on pressure and friction. The pressure is generated by a standard size servo. For good engagement I need between 600-1200 lbs of force generated onto the clutch pads. As with any mechanical system you can gain mechanical advantage but you loose travel. In short I need to go back into the gearbox and re-shim the clutches for proper engagement. At the beginning of the day the clutches engaged very nicely where the tank would rear up on its end. Towards the end of the day they started to wear and the tank would barely move. The proof-of-concept seems to be a success but I still need to work out a couple of bugs. I ordered new radio gear and should have it this weekend. Now I just need some time to pull apart the tranny.

brice_arnold

My Feedback: (6)

Because I machined all the parts myself it wasn't too bad but if you look at the invested time then it's through the roof. Looking at your guys projects though time invested is kind of an understatement on these tanks. If you just looked at machine time at $60 an hour that already puts you at $12K. Here is a quick breakdown of off-the-shelf parts and materials.

Motor $1000
Pipe $300
Baja 5T Parts $700
Custom Painted Baja Body $500 by Crafwerks-RC
Radio Gear $460
Gears for Tranny $375
CVD's $320
Bearings $500
Raw Materials $1000
Hardware $350
CST Bumpers $250

It adds up fast.

brice_arnold

My Feedback: (6)

Doing an electric version would be soooo much simpler. Just throw on a couple of brushless motors, a gear reduction and get rid of the complicated tranny and engine.

Panther G

I quit!!!!!!!!!!

Panther G

But i wouldn't mind putting a few man hours on her LOL

bigskydude

cool concept of a "performance" tracked vehicle, but gotta lose the truck body....car bodies just don't look right on a tracked vehicle..better to do something custom(like a driver in a rollbar'd cockpit) that fits the whole "tracked" theme. Just my 2 cents....very nice workmanship however!

brice_arnold

My Feedback: (6)

That's a good point. It actually looks really cool in person with the truck body. I have had that body for almost a year now and it kind of defined the color scheme for the anodizing.

I have another project in mind though. I was thinking of converting my 5T supertwin in to a half-track keeping the twin engines and just replacing the rear wheels with a smaller version of my track assembly. If I went forward with this project I could look at doing a welded tube open-frame/rollcage.

gulfstreamI

The tracks may need to be wider the spread the weight of the vehicle if it is traversing on muddy terrain. My first impression on the side view shape of the tracks was from European designed tanks of WWI and WWII. Good job on the engineering.[sm=thumbup.gif]

heavyaslead

I would protect those tracks-

Those tracks look so nice especially the anodized color! Adding rubber pads (like the Leo tank) like a bolt on block that would protect the metal on street driving and grip better.

pattoncommander

The thing could use a coat of flat OD and a turret. The demo model with the very sleek lines and classy frame should retain the white T and great blonde camo net. [sm=spinnyeyes.gif]

BURT3D

That looks great. That would be on a shelf getting dusted every day.