Prancstaman's X1 Scorpion

Man that thing is looking mean. Can't wait to see a driving video!

MasonMcK wrote:

Man that thing is looking mean. Can't wait to see a driving video!

Thank you, It's noon right now, It's a light drizzle outside and cold. Lets see what I can do. Time to make it or break it, LOL. This should be interesting!!!!!!

Boy, that looks really great. Definitely the most labor intensive build this year.

Been a few hours since you posted that last post. How'd the test run go?

Hay People,
Test drive didn't go to good, Issues with the belts from the output shafts from the gearbox to the sprockets. I just don't have enough of grip with what I have on there to turn. It moves forward ok, but belts slip backing up which is no big deal, and slip to try to turn which is a big problem. The belts I bought at first just stretched and slipped. I went out and got 2 automotive V belts, put them on and redid the belt tensioners to have more pressure on the belts. Still no good. I stopped the stretching with the automotive belts but they still slip the same way. To fix this I'll need to put either bigger pulleys on or add 2 more sets to it, which means redoing the linkage to the belt tensioners to make room. Don't think I'm going to make the deadline.

Here's the video of the test drive. It still was a blast to drive........

So the belts go directly to the axle shafts with the track gears right? I guess there is a decent amount more effort on them than if they were geared down through a transmission since they are 1-1 with the track. Maybe like you said, add another set of belts or something. The good thing is the tracks don't seem super prone to jumping off or jumping over the gears. Seems like once you iron out some minor teething problems it should work pretty good.

i do hope you make the deadline that thing is awesome even if your having issues getting it to work for you

mr.modified wrote:

So the belts go directly to the axle shafts with the track gears right? I guess there is a decent amount more effort on them than if they were geared down through a transmission since they are 1-1 with the track. Maybe like you said, add another set of belts or something. The good thing is the tracks don't seem super prone to jumping off or jumping over the gears. Seems like once you iron out some minor teething problems it should work pretty good.

Yah, You're thinking right on the pulleys, 1 to 1 from gearbox to sprocket axles. Early on I thought about changing this to get more advantage but I'm building this for speed and light crawling, would have been too boring for me, LOL. It takes alot to just turn it. Testing it, now I know I have enough hp for it. The tracks worked way better then I expected, I didn't even weld up the links like I said I would and they didn't even stretch. I hoped off it and twisted the throttle, you can see the tracks just digging into the ground. This build is far from being over.

redzz02 wrote:

i do hope you make the deadline that thing is awesome even if your having issues getting it to work for you

Sorry Red, I can't make it. I'll make a final post tomorrow with what I got. But this build is far from being over! I would have made it if the test drive went OK but no deal. Just not enough of time.

Well People, I did not finish the Build Off!!! I do not qualify as being complete.  

Where I stand right now. The test drive pretty much went down the toilet which just happens to be where I thought up the idea to build this project. I'm so bumded right now. But this build will continue on my You Tube Channel. This is only the Beginning of this project. Big plans will come from this build.

With that said, on to the pics and what went wrong.

Here's the problem. Pic is from the output shaft of the gearbox with a 4 inch pulley, belt, sprocket shaft pulley which is 4 inches, linkage. and belt tensioner.
What happened on this setup- the linkage worked kinda as planed. The idea was to lock the tensioner pulley with the linkage to get reverse by keeping the rod straight from the lever that twists to the tensioner, this made the linkage nonself adjusting. This worked until the belt stretched which I adjusted, which stretched again. So I gave up on reverse and slotted the hole so when the belt stretched would not effect the tension on the belt but the belt just kept stretching. It was a vicious cycle to no end. When I slotted the tensioner hole, that was when I was able to turn but the belt just kept stretching. The belts was the utility belts for an edge trimmer in the video. This pic is of another set of belts I went and got from the auto part stores, took 3 hours of driving to get 2 belts from 2 different stores. They are automotive belts and are made with threading inside of the rubber to keep them from stretching. I swapped out the belts for the ones in the pics which took another 3 hours and I fixed the stretching problem but did not grip the pulleys because they didn't wrap around the pulleys as much like the utility belts did. So off camera I redid the test drive and still the same problem, belt slippage. This time I literally smoked the belts so bad that the pulley turned red. By the time this happened it was 11 o'clock at night and that was that. I just don't have enough of grip from the 4 inch pulleys.    


Here's a closeup of the second set of belts (automotive belt). You can see the fraying on the edges of the belt where I smoked it. When I switched belts I also had to move the tensioner pulley closer to the pivot point because these belts was just a bit smaller which is good in away because it increased pressure on the belt from better leverage but I lost grip because of less surface area on the pulley.


Ok, what else didn't work- The track tensioners never moved, guessing not enough of spring pressure.
                                   The air shocks in the back are weak even though they was charged to 120 psi.
                                   Needed suspension stops because the very back ground wheels was rubbing
                                      on the output shafts of the gearbox.
                                   Could not turn because of the belts slipping!!!!!
What was not completed- Guards on various spots on the vehicle, over the tracks and between driveline and
                                      legs.
                                   Hood.
                                   All electrical was never started. This alone disqualified me of being completed
                                        since the engine only starts with a starter.
                                   Paint not finished.
NOW, What did work- Tracks worked flawlessly with the sprockets.
                             Brakes worked great, all 4 of them. Just one caliper stopped this thing (trying to turn)
                             and held back the 11hp Briggs I built for torque after going through the gearbox.
                             Drove straight forward pretty good. Off camera I did a high speed test that was about
                                    10 to 15 mph.
                             Rode smooth
                             Engine ran great, clutch worked great, belts from engine to midshaft to gearbox worked
                                    great.
                             Chassis held together with no issues.
                            Seat is comfortable

There you have it, all layed out. If the test drive would have went OK, I would have thrown the rest together enough to qualify. But by my standards I feel if I couldn't atleast move forward and turn left and right, I should NOT qualify as being complete. So I yield to the builders who have finished their projects. It's been fun doing this Build Off. Good luck to those who qualify!!!   

Here are a couple more pics of my project of what I have done. As I mentioned before I will continue this project on my You Tube Channel if interested in seeing me getting this project going. With my luck I probably will get it driving next weekend. ENJOY!!




I never measured this but there's got to be about 10 inches of ground clearance here.


The test drive was done with the track master links not welded like I said I would do. Surprised they didn't stretch. I think I'll leave them open for now.


This has been a prancstaman Build. Thanks for following the build.

And Thank You Doc Sprocket for having me in this Build Off. IT WAS A BLAST!!!!!

                                           THE END!!!!

Hay People,
I'M BACK!!! LOL!!! No worries. This project is far from being done, and plan on sharing every bit with you people, the good, the bad, and the ugly!!

Since the end of the 2015 Build Off, November 30th at 9:59 pm, I packed it up and dragged it to the side with my mower, That sucked. Then threw a cover over it and tucked it in for the winter. Pretty mild winter here, only snowed a couple of times. Didn't even use my snow blower because all the major storms missed us here, but it sure got cold and I don't move to well in the cold anymore.

Here it is, pulled the cover off a couple weeks ago and took a couple pics.


He keeps peeing on it!!!



So, during the winter, just been thinking and planning on how to fix this thing to where it will work. Alot of problems to fix but this time there's no time limit. Unfortunately I have other projects in the works that need to be done also so the posts will come slower then before but will go forward.

                     With that said: I'll list the problems-
No electrical, I have to jump start it right now
No body panels or guards
Tracks slack to much coming off the sprockets
Track tensioners don't work (apparently)
Track guide inlets on the bogies need to be opened up more
Need a fuel pump, tilts to far back to where the tank is even with the carb and stops flow
Engine governor needs to be adjusted higher
Redo the drive belts from single belts to duel belts and bigger pulleys
Need Suspension stops at least in the back A-frames
The back drops down while starting off because of weak shocks and the sprockets want to pull the back down

This is just off the top of my head, I'm sure there's more. Next post will be the plan on starting to fix these problems. STAY TUNED!!

And Thanks again Doug for moving this here so I can continue the tread.

Nice! Been wondering when you'd bring this thread back to life!

Cant wait for another update.

MatthewD wrote:

Nice! Been wondering when you'd bring this thread back to life!

Cant wait for another update.

Thanks, been working on it little here and there. Mostly just thinking and planning.

This looks like a neat build. Sucks it failed on you. I cant wait to see this thing brought to all its glory!

Hay People,

Alright, enough talk about what's wrong!! Time to plan to fix it!!

The electrical can wait till all mechanical is working right. Won't be too complicated of an electrical system.

Body panels should be the last thing, pretty much. Includes hood, leg protection from belts (inside),and leg        protection from tracks (outside).

Governor needs turned up, it's just a matter of bending that arm. Although I just might modify the governor sooner rather then later so I can run a power adder I plan on using. Yes, that's right, a power adder. Nothing like spraying a little home brew in a motor, LOL. I was seriously thinking about spraying a mix of water/methanol into the engine, BUT if I can get a hold of some Nitro methane pretty easily I'll use that. The mix of Nitro methane would be 10% with 70% alcohol and maybe 20% water, if it all mixes together, don't know the mix yet that is if it all will even mix together, if not I'll just dump the Nitro methane in the tank. Nothing like a good kick in the @$$ to get moving seems pretty tempting, LOL. Although the water/meth mix would cool the cylinder under serious abuse. NOS seems like too much of a cleeshay these days. WE SHALL SEE!!! LOL!!

Adding a fuel pump seems to be an obvious choice to the fuel system since I made an exact spot for the fuel tank and would be too hard to move. I'll mount the fuel pump on the motor should make a clean install.

All this mentioned can pretty much wait till I get this thing to turn the way it's suppose to. Stay tuned for the next post........... Should be tomorrow. LATER!!

Rockinator wrote:

This looks like a neat build. Sucks it failed on you. I cant wait to see this thing brought to all its glory!

Glad you like it. It didn't exactly fail though, just delayed till spring. During the Build Off I had other parts that didn't work the way they was planned to work and had to redesign them also. It was just bad timing, it being the end of the Build Off. If you get it right every time, you don't learn too much. It's all on how you look at it. Enjoy the build.

Hay People,
Ok, what gets fixed first are the pulleys coming off the gearbox and going to the sprockets (ofcourse), just not enough of grip and surface area on the pulleys to do some good. I tried everything I could think of and then some.

So the next weekend after the Build Off, I went out and got a couple more belts, 1 inch longer to wrap around the pulleys more. I had them wrapped around to where the bottom part went up between the pulleys and almost touched the top. Then tried another test drive. This time they still slipped, so I disconnected the linkage on one side because I got tired of adjusting it. Yes, the linkage is part of the problem. With the linkage off one side, I started it up and tried to turn with me off it. The end result.........



I snapped the belt. That means I finally got enough of grip but the belt wasn't strong enough. It could have just been a defective belt but I don't think so. So, that's when I finale put it up for the winter...

Now, the plan is going to be putting as big of a pulley in there as possible but will be 2 of them side by side on both shafts with duel belts for each side. I can put up to a 6 inch pulley on both shafts which will triple the grip. I'll do it in 2 steps though, The first step, I'll put duel 4 inch pulleys on the gearbox shafts and duel 6 inch pulleys on the sprocket shafts. That will cut my speed in half but boost torque. I'll redo the linkage too. I got a different way I want to try, should be able to keep reverse with it too. The second step would be duel 6 inch pulleys on all the shafts if all goes well with the first step.

Next post will be how I plan to tackle the Idler wheels not keeping the tracks tight and rear shocks not being strong enough. Maybe tomorrow or the next day for that post, Later.

Think a lawn and garden belt is heavier duty than those type with the ribs? Dual belts and also lower gearing should make things work a lot better though. Then belts probably won't be an issue anyway. Keep us informed!

mr.modified wrote:

Think a lawn and garden belt is heavier duty than those type with the ribs? Dual belts and also lower gearing should make things work a lot better though. Then belts probably won't be an issue anyway. Keep us informed!

Yah, the lawn and garden belt and the the auto belt with the ribs are about the same in strength, which is a 1/2 inch lawn and garden belt and a 3/8 auto belt. The way they are made is different though. A lawn and garden belt, I dissected one, is made with a solid rubber core with a cloth spiral wrapped and glued its length of belt, and it does have an end to the cloth wrap. They are made to stretch a certain amount. The auto belt is made like a tire with rubber layers and cloth thread in between the layers, the threading runs length wise and sideways or in an X pattern. They will stretch very little, and when the thread breaks is when the belt breaks. The ribs or cogs on the auto belts, only certain kinds, will make the belts easier to bend around pulleys, comes in handy when you have a very small pulley and the belt wraps around it easier then a belt with no ribs or cogs, you get better grip from that. Bad thing about auto belts is that they only go as big as 60 inches.

I'm hoping the duel belts and the smaller pulleys on the gearbox will be overkill, got my fingers crossed mr.modified.

Hay People,
Ok, the first thing on fixing is the belts. If it moves and turns, that would be great!! I'll move forward when this happens. Part 2 of my plan will be suspension issues and track tension issues.

I'll start with suspension issues. Rear shocks are weak because of how I have the top mounting point close to the pivot point of the A-frames. Front shocks seem OK for now. The rear are the issue. I need to determine how far I want the rear A-frames to compress to where the wheels don't hit anything and move the top shock mount away from the A-frame pivot point. This will help but not completely. I also need to make an actual stop for the A-frames. Next there's the track tensioners that don't work. Pretty evident by how the tracks come off the sprockets and dropping down before the draggers.

I think I can fix all 3 issues with one plan. I think by putting linkage from the A-frame to a swing arm then to the tensioner rod will fix these 3 issues.


My thinking is: when I start off, the rear A-frame compresses, which loosens the track since the front idlers are not moving forward. Running a rod off the rear A-frame will move forward. Now control this moving rod with a swing arm between the 2 components. The swing arm will multiply the movement going to the idler tensioning rod pushing forward. Ha!! 2 wrongs can make a right!!! LOL. Anyways, this will probably be a rough ride because I would be physically locking the 2 components together so, the rod coming off the A-frame going to the swing arm needs to be telescoping and fitted with a stiff spring to absorb the shock from bumps.

Somewhere should be a balance to where the A-frame stops moving, hopefully before full compression which will be the suspension stop. Plus will add pressure to the A-frame to keep from compressing before it stops. I guess we shall see, been wrong before.

Sounds like it should work. Plenty of engineering going on!

MatthewD wrote:

Sounds like it should work. Plenty of engineering going on!

Fingers are crossed!! I've seen this idea on other tracked vehicles but on a smaller scale and was designed into the system from the get go. For me, will be a fix. Thanks for the good word.

Hay People,

Worked on the Scorpion a little Saturday. I have this vehicle on another forum also and someone volunteered there time to help me. This guy I think is an engineer and will draw up my track system in CAD to figure out the rod and swing arm setup for me. This will save time on the way I do things and will have all the figuring out already done. I would just have to make it and put it on. COOL HA!!

Anywho, He needed measurements of what I got on my system. You know, wheel size, A-frame length and measured mounting points. Never took any of those measurements until now. plus had to figure out all suspension travel and stopping points. Pretty much just documentation of what I got for Pierre to do his thing.

Here's some pics of what I did. I picked pics with no measurements to see better.

This one is full extension of the suspension with the tracks tight. I measured the clearance underneath and it has 11 inches of ground clearance. WOW!!! The contact patch is 38.5 inches long by 10 inches wide, which in total is 385 cubic inches X by 2 tracks= 770 cubic inches of track touching the ground. Vehicle weight is around 600 lbs, so each square inch has .779 lbs of pressure pushing on the ground, or something like that. My tracks do have cleanout holes between each track plate so the ground pressure will be a little higher, probably just under 1lbs per square inch sounds about right.


This will be the lowered ride height. Note that the A-frames main surface is pretty much flat. This ride height will be for high speed driving. The lower stance is spread out more for more stability, less rocking in other words.

Here are the numbers- Contact patch is 44.5 inches x 10 inch wide track x 2 tracks = 890 cubic inches of contact with the ground. Ground pressure is 600 lbs divided by 890 cubic feet = .674 lbs psi of ground pressure. Maybe .75 lbs psi of ground pressure sounds more realistic to me.

With all that figuring, This pic just looks awesome, I like this stance the most, LOL.

Hay People,

Started gathering parts for redoing the drive system. Went to Tractor supply for the pulleys and wouldn't you know it they only had one, so off to the Customer Service desk to have them order 3 more.

Might be in in a couple of weeks to a few days. I think that's worse then the cable guy coming to your house, LOL. And to beat that, it's a 20 mile trip just to get there one way, through a construction zone.

Then when I get all the pulleys fitted, I need to get the belts. That should be an adventure.

Hay People,

It's been 6 weeks since my last post. I was talking with my kid looking at this project in the yard covered up. I was telling him that I was still waiting on the parts to come in from tractor supply and decided to call them. This was Saturday. Guess what, the pulleys came in probably about 2 or so weeks ago and tractor supply never called me. They was on a rain check and how it works is when the part comes in, you got 10 days to pick them up. Well, it was past the 10 days and the parts was on the shelf. Asked the lady to grab them and I'll be in the next day to buy them. All worked out to where I finally got the the rest of the pulleys and with my imaginative wording got a store manager discount the next time I come in, LOL.



OK, got the pulleys. I need to clear up some projects around the house and finish my mini bike I am building on my You Tube channel, then I can restart the work on this project. It will be a couple more weeks. Sorry people but good things come to those who wait, LOL.

Yes! Progress! Next I think you should buy an old bulldozer and then build a body shell around it that looks like a tank......maybe....

A tank, nah. I might go smaller though. I was thinking of making one of those "Magic Carpets" if you know what that is. But the bigger plan with this project is to start another one or build off this one and make it stronger. I'm thinking one of those Harley Super 88 engines with a different driveline to match.