Potatocat's 6WD/6WS E-Raminator

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You should really look into programmable steering, seen lots of multi wheeled, multi steer trucks in real life and the tires don't all turn at the same rate or angle for efficient steering. During tandems rear steer the arc the tires traverse is different and require different levels of steering input for a nice transition and not scrubbing the heck out of the tires. May not matter much on dirt, but i would expect better steering response non the less. Look up Mobil cranes for some easy reference material. Something above 75ton lift. (Largest I know of that does not have rear steer as standard) the 210 we most recently used had triple rear and duel front axles. They all steered. Was just art to watch it move around obstacles.
I think if I had more than three axles and was running onroad this would be something I would consider. I had tried a reduced middle axle travel setup in the past by reducing servo throw but discovered it just was not worth it since it increased the risk of tire-on-tire scrub. Traction scrub itself is going to happen even if I had perfect Ackermann angles since monster tires are so wide... so I figured just to say forget it and go with maximum and equal steering travel on all axles.

I do have to agree with you how neat the multi-programmable steering is on something like Liebherr cranes- as they can do semi-automatic mode changes from crab to claw steering on the fly. It just isn't a good fit at all for my trucks. Thanks for the heads up though!
 
Finally! Some progress and I now have a chassis and nothing is supported on wooden blocks anymore. I drilled some of the holes and made some cuts to the frame rails, which were just enough to get everything that I have mounted for test fitting. The frame rails are not done yet as I still need to make cuts to the top of the rails to trim them down a bit. Battery placement is still TBD so there will be a good amount of assembly/disassembly until everything is sorted out.


I decided to go with a full length frame rail of 60". Tires were test fit just to get a better look around at things outside the cramped confines of my workshop. This picture shows a comparison with Mammoet which is at this point pretty much is 1/2 the size of the new truck. Mammoet is no light weight either, already at 24 lbs and nearly 30" long.


The next major milestone is the driveline, but I still have a lot of small doodads to turn out on the lathe. I am still making minor design changes but hopefully things will solidify now that I can mock everything up with a full chassis to work with.

Thanks for reading!
 
Dude this thing is awesome! I really like what your doing here and attention to detail. Cool seeing your smaller rig running too. Keep up the great work!!
Watching with anticipation on this one!
😎🏁🏁
Thanks man! I don't have a lot of updates this week as its been a busy but fun one, with the Memorial Day holiday weekend going on and me pulling dad and lifeguard duties in the backyard pool while the kiddo had friends over the weekend. It was awesome because I had time to chill and think about some of the uncertain parts of the design, resolving these issues. This coming weekend I will be likely busy as well but I may be able to start machining a bunch of the smaller parts that will be needed.


I did manage to finish drilling holes in the chassis and remove excess material from the rails that I intended. There's tool marks and a few imperfections since I had to do this by hand but its all good and generally acceptable to me. Prior to final assembly I'll take everything apart and clean those areas up. I am kind of debating if I should use ceramic coating on the aluminum when I get to that point...

Now I can finally start to work on the driveline. Limiting straps are an absolute must on a 6x6 and you can see all the black rope laid out. This is just 6mm paracord. A hangman's knot is used on the top part of the strap mount, while a bowline on a bight will be tied in for the axle end. The goal here is to have no slippage at all. Once the final dimensions are set and the straps have been tensioned under load, I will whip tie the ends of the cord.

The shocks had to be canted inwards a bit to avoid tire scrub, but all of my 6x6 trucks have varying degrees of this going on so its really not a big problem to me.

Thanks for reading!
 
Hi all,
The past few weeks have been busy but I still managed to get some work done. The driveline is mostly finished but I am missing a few things like spacers, captive collars, and some chain links. A view from the front shows the chain drive that sends power to the rear axle. The motor still needs a shaft turned for it that sends the output from the other side of the can.


A view from the back shows the other end of the propeller shaft sending power to the rear axle, but I am short a few links of chain so it is not hooked up.


Shortening the rear universal slider was necessary. It hurt having to do this though.


Progress may be slow but I'm definitely getting there. Once the driveline is fully functional I can start working on the wiring harnesses and first battery module to do some basic testing. Then comes the body, which will be a simple fiberglass shell. Thanks for reading!
 
Hi all,
No major updates, but progress continues steadily. The driveline is completed enough for me to do static testing, so that means electronics work has started so that I can get things running.

Steering will follow the same 6WS methodology that I have used in my previous models to good effect.

While there is still a lot of machining to go, most of these are smaller or simpler parts. Link rod conical washers and spacers are all done for each link connection for example.

The brake servo will go between the rear and mid axles, and all of the cables are upgraded to Shimano units from the mountain biking world. I will have to fabricate the stops and sliders for all of these but the design is simple and straightforward. I originally was going to use a hydraulic brake for just the front axle but nixed that idea when I realized the hydraulic lines are PUSH and cable are PULL and I would be stuck with two opposing directions for actuation. I am not using that particular Futaba servo, but it served as the template for what will go in there eventually.

The reoccuring word of design for this truck is "bandwidth". Everything is being given as much bandwidth and room for growth as possible. For example the servos have been re-wired to use thicker gauge cable and power is wired up to use XT30 connectors. The PWM signal wire has been wired to use 2mm bullet connectors. The cable runs along the link rod are are fully armored. The PWM connections are also shielded.

And again apologies for slow updates but its due to my hectic schedule. Thanks for your patience!
 
The path to driveline testing is almost there, now that I have the mechanical brake linkages setup. Three brakes are needed for each axle... and the front brake is on the center instead of just being slotted in order from front to rear. This is to ensure the front axle always gets the most prime response. You may wonder why the travel is so short, and what happens to this sliding block if the throttle is activated since it seems like there is nowhere for it to move forwards. This is intentional and will be explained later.

I did not have a slitting saw so I tried to cut the grooves in the brake link block by hand. It isn't perfect but it is good enough here.

Next up is laying down the foundations for the electronics. The box with the emergency power off button is the receiver power distribution panel. In a separate open box behind it as pictured is where the receiver, lighting, and onboard microcontroller will go.

The reason for a local Raspberry Pi and Arduino compute hub onboard is to process inputs from the radio and execute on them, along with collecting telemetry for storage. Arduino will be constantly reading PWM data from the receiver and streaming it to the Raspberry Pi which will make the decisions on what to do about it. The brake servo pictured above only actuates if certain conditions are met. It only moves if a 3CH switch is enabled that allows brake action or overrides it. This is how I will eventually have reverse work from the ESC without interfering with the mechanical brake. Additionally, the brake servo only begins moving if the throttle has been detected to be below the neutral point.

For the sake of driveline testing I might not attempt to get the brakes working as intended yet, and just sling them on their own proportional channel and limit the travel in one direction. I think you guys can see what direction I am going in all this.

Thanks for reading!
 
Hi all, some more updates - its been a busy month work-wise but I still had chances to work on this project and made good progress since last update.

The chassis is now more or less mechanically complete for its first phase, and ready for testing. I added anti-sway bars but the current spring loading is comically small. I'm leaving them as-is until I can get some drive time in to figure out how thick the high-carbon steel spring should be.


I changed out the stock springs on the Raminator V3 shocks for something much more substantial. I have not done a precise measurement on the spring rate of the original springs but these have a spring rate of 0.61lb/mm and feel SO much better. This subjectively feels like a stiffness rate of around 2x or 2.5x the original ones and should work well. I may have to change the damping oil rate to be a bit thicker but I won't do anything until I can drive the truck for a while and see how it handles first.


The motor is now hooked up fully to the rest of the drivetrain. I elected to just turn out a shaft that attaches to the 'back' of the outrunner shaft and extends it so it is now the 'front' and drives a pinion sprocket for the rest of the chain drive. These chains are currently exposed but I will make covers for them in fiberglass.


Another shot of the drive setup that might help all this make some more sense is below:


I am pivoting to working on the battery modules now, so I can start test driving the vehicle! This is how the 8S4P "phase one" layout will look.


(continued in next post)
Steering test of the direct-power servos shows them to work well even under the heavy weight of this truck - remember that these are routed to their own dedicated power connections as to not strain the receiver bus. Six wheel steering is being done here without any channel mixing - all three axles share the same PWM signal connection, but the front axle has its signal piped through a servo reverser to get the 'claw' effect. This frees me up to use virtually any radio transmitter of my choice. I am torn still between a pistol grip and a twin-stick setup and have not yet decided.

Animation of steering servos moving

Proper knotting for my limiting straps is finally done, along with a shuffling of suspension layout to eliminate tire scrub. These are double anchor hitches tied down into the axle.

This is my primitive but effective power distribution panel for the accessory battery. This is only handling 7.4V (2S LiPo) but I put this in place just to protect my electronics in case of anything catastrophic. There's just a simple LVC buzzer on the accessory battery for now to handle when I should stop driving. The EPO switch cuts off receiver bus power, and then allows the brake return spring to do its job to stop the vehicle.

The mechanism deck is taking shape, and I will have a simple quick-release setup for the battery modules eventually. For now I am figuring out how I am going to do things. Originally I was going to use NATO slide rails with quick clamps but I found a much simpler and elegant solution which requires a design change. For "phase one" I am just going to velcro things down just to proof-of-concept everything out.

Deadlifting this truck is becoming problematic and I will likely need to do some more freeweight training during the offseason just to move this beast around! The sheer weight is one problem but the bigger one is that unlike a bar and plates- the bulk of the truck cuts off many easy lifting angles to get it up and down from a table. I am also of a slender build, since I am an ultramarathon distance swimmer and not a sprinter, so I will focus on working with what I have. The bare chassis weight of the truck right now is 125lbs. Its a bit above my original target. Batteries are going to be around an extra 15 lbs, and body will probably be around 5lbs since it will be fiberglass and not polycarbonate. Still I do not have many complaints, weight concerns are par for the course for large electric vehicles.

So I am tantalizingly close to getting initial drive functionality out of this truck. One step at a time though. I am shifting my fabrication focus now on making the fiberglass masters - basically chainguards and body parts for the vehicle next.

Thanks for reading!
 

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Hi all, some more updates - its been a busy month work-wise but I still had chances to work on this project and made good progress since last update.

The chassis is now more or less mechanically complete for its first phase, and ready for testing. I added anti-sway bars but the current spring loading is comically small. I'm leaving them as-is until I can get some drive time in to figure out how thick the high-carbon steel spring should be.


I changed out the stock springs on the Raminator V3 shocks for something much more substantial. I have not done a precise measurement on the spring rate of the original springs but these have a spring rate of 0.61lb/mm and feel SO much better. This subjectively feels like a stiffness rate of around 2x or 2.5x the original ones and should work well. I may have to change the damping oil rate to be a bit thicker but I won't do anything until I can drive the truck for a while and see how it handles first.


The motor is now hooked up fully to the rest of the drivetrain. I elected to just turn out a shaft that attaches to the 'back' of the outrunner shaft and extends it so it is now the 'front' and drives a pinion sprocket for the rest of the chain drive. These chains are currently exposed but I will make covers for them in fiberglass.


Another shot of the drive setup that might help all this make some more sense is below:


I am pivoting to working on the battery modules now, so I can start test driving the vehicle! This is how the 8S4P "phase one" layout will look.


(continued in next post)
Steering test of the direct-power servos shows them to work well even under the heavy weight of this truck - remember that these are routed to their own dedicated power connections as to not strain the receiver bus. Six wheel steering is being done here without any channel mixing - all three axles share the same PWM signal connection, but the front axle has its signal piped through a servo reverser to get the 'claw' effect. This frees me up to use virtually any radio transmitter of my choice. I am torn still between a pistol grip and a twin-stick setup and have not yet decided.

Animation of steering servos moving

Proper knotting for my limiting straps is finally done, along with a shuffling of suspension layout to eliminate tire scrub. These are double anchor hitches tied down into the axle.

This is my primitive but effective power distribution panel for the accessory battery. This is only handling 7.4V (2S LiPo) but I put this in place just to protect my electronics in case of anything catastrophic. There's just a simple LVC buzzer on the accessory battery for now to handle when I should stop driving. The EPO switch cuts off receiver bus power, and then allows the brake return spring to do its job to stop the vehicle.

The mechanism deck is taking shape, and I will have a simple quick-release setup for the battery modules eventually. For now I am figuring out how I am going to do things. Originally I was going to use NATO slide rails with quick clamps but I found a much simpler and elegant solution which requires a design change. For "phase one" I am just going to velcro things down just to proof-of-concept everything out.

Deadlifting this truck is becoming problematic and I will likely need to do some more freeweight training during the offseason just to move this beast around! The sheer weight is one problem but the bigger one is that unlike a bar and plates- the bulk of the truck cuts off many easy lifting angles to get it up and down from a table. I am also of a slender build, since I am an ultramarathon distance swimmer and not a sprinter, so I will focus on working with what I have. The bare chassis weight of the truck right now is 125lbs. Its a bit above my original target. Batteries are going to be around an extra 15 lbs, and body will probably be around 5lbs since it will be fiberglass and not polycarbonate. Still I do not have many complaints, weight concerns are par for the course for large electric vehicles.

So I am tantalizingly close to getting initial drive functionality out of this truck. One step at a time though. I am shifting my fabrication focus now on making the fiberglass masters - basically chainguards and body parts for the vehicle next.

Thanks for reading!
Nicely done mate. May I suggest you look up a secured bow line knot. We use them for rope rigging here at work. Very strong knot and with the proper stopper knot it is very secure, yet can be easily taken apart after heavy load. Whatever you used for your limiting straps looks like a pain if they need undone. Idle suggestion... lol.
Eagerly looking forward to your next post.
 
Nicely done mate. May I suggest you look up a secured bow line knot. We use them for rope rigging here at work. Very strong knot and with the proper stopper knot it is very secure, yet can be easily taken apart after heavy load. Whatever you used for your limiting straps looks like a pain if they need undone. Idle suggestion... lol.
Eagerly looking forward to your next post.

Thanks! I actually was going to use a nautical/secure bowline originally, but passed on it only because the knot ends inside the loop. This would have made it somewhat harder to whip cleanly. I had originally preferred it for its slip resistance, but the double anchor hitch comes in a close second to me. It is a similarly strong knot and is only marginally harder to untie after load release.

The top end of the limiting strap is a hangman's noose and works because I don't need to re-tie that side at all. I went for that because of decorative reasons as opposed to practical ones. Because of the design I used for the top capture mount, I needed a knot that would tighten under load instead of something static like a bowline or a hitch.

Initially I was not sure if this would work, but after pre-loading the paracord I found that it surprisingly does not stretch all that much unless I leave it soaking in salt water hahaha
 
Thanks! I actually was going to use a nautical/secure bowline originally, but passed on it only because the knot ends inside the loop. This would have made it somewhat harder to whip cleanly. I had originally preferred it for its slip resistance, but the double anchor hitch comes in a close second to me. It is a similarly strong knot and is only marginally harder to untie after load release.

The top end of the limiting strap is a hangman's noose and works because I don't need to re-tie that side at all. I went for that because of decorative reasons as opposed to practical ones. Because of the design I used for the top capture mount, I needed a knot that would tighten under load instead of something static like a bowline or a hitch.

Initially I was not sure if this would work, but after pre-loading the paracord I found that it surprisingly does not stretch all that much unless I leave it soaking in salt water hahaha
Nice lol. Yes it's a pain to tie the security knot if your going for a nice tight loop.
 
A few updates as steady progress is being made:

I jumped at the chance to get a Hobbywing Max4 ESC as they have begun reappearing in stock. Be aware that some units are NOT shipping with a sensor cable despite being listed on the product description as being included. This is a mistake on the factory side, and a shout out to AMain Hobbies for sending one. Apparently other people are also having this problem.



This is the ESC mounted on its mechanism deck alongside an accessory 2S battery. I think I am one of the few people to use the whole Amass XT family of connectors all on one model. XT30 is on the servos, XT60 is for the accessory battery, and XT90 antispark are for my battery packs. This is a test loadout of the full 8S4P configuration. The battery crossbar is connected to the ESC using a QS10 connector. I really like this connector design, and though it is technically under-spec for the absolute limits of the Max4 I had to give this a go. For working on this truck, I have adapted the use of a pair of dollies so that I can easily roll it around on the floor and spin it as needed to access certain areas. That's what all the wood is in this picture below.


This is a short video showing the truck moving. Its within the confines of my basement so there's not much happening here. Note that cogging is a big issue. I am aware of this of course and full-on expected it. The amount of power being given here according to my transmitter on throttle is only around 6% or so. The next move is to build sensors for the motor, and now that I have an ESC that can make use of those sensors performance should jump waaaay up. Once the sensors are installed and configured, I can record some proper running video. The cogging limits me very much at this point.


This is a test of fit into my 1:1 car. It does fit but with only about one inch front-to-back to spare. WHEW. I have a pair of pressure-treated lumber planks that serve as my entry ramp. It is possible to push the truck unpowered up the ramp but the process and mechanic almost feels like a pair of deadifts. I am either going to be super jacked and tone or I will have a hernia after this!


The next step aside from getting sensors for the motor working is to begin work on the body, and other components like chain covers. These will be made of fiberglass and I am going to start figuring out the whole process ASAP. The truck is validated and functional, so I feel like I can sleep a lot easier knowing all of the major components work. Now what remains is to tune everything so it runs properly!


Thanks for reading!
 
Dan and I are sat here drooling at this thing, its awesome! We would love to feature you in a Youtube video someday!
Thanks Owen and Dan! I would love to make the trip once the truck is ready. My progress has been slow recently but here are a few updates anyhow:

I tried my hand at making a motor sensor system for the Hobbywing Max4 to use with outrunners other than the 70125 that it was exclusively pair with, and long story short... things did not work out. The journey here may be interesting for others so I will share anyway. I took a sensor board assembly from a 540 motor and basically desoldered all three Hall sensors on its board and then wired up extensions to them instead.


These were then wired up to a small breakout board with standard 0.100" pins, and a set of otherwise identical but different form factor Hall sensors were wired up and connected one by one to the breakout board. The motor sensor cable then connects into the sensor board and you can now see it serves nothing more than an extended sensor middleman device. Here is the board from above all soldered up and packaged inside a legacy 75MHz receiver casing:


The intent here is to get any other sensorless motor new life to work with the Max4 in sensored mode.The completed concept is not new and many others have done this before, I simply watched what others did and copied it- standing on the shoulders of giants. The next step was to machine a ring outside the motor can to properly align and adjust the Hall sensors so they are sitting 120 degrees equidistant of each other. I tested this out by wiring up a different outrunner to one of my sensored ESCs (a Quicrun) and literally using hot glue and cardboard to hold the sensors down just to prove the concept out. It worked, so the next step was to try and mount this up and test with the 50cc motor before making the ring.

Long story short... it did not work. I suspect (but cannot verify 100%) that the unused thermal sensor pin might be used to do something proprietary to get the Max4 to work with the 70125. Without a 70125 motor I cannot be certain. I tried using both latching and bipolar Hall sensors but the Max4 would not start up in sensored mode. Oh well, so this was "Plan B" and this idea was ditched in favor of the original "Plan A" - which is MORE POWER.


Pictured above is the intermediate 100cc motor that I ordered in haste as I am still waiting for my backordered 150cc. The older 50cc motor is still mounted in the truck as seen. The new motor is nothing flashy, a Turnigy CA120-150kV outrunner. Intended for airplane use, its been around for a few years and seems to be decent at its job despite having somewhat low maximum power ratings. It is seen above with its original shaft facing the "wrong" way. I machined an extended shaft for it using 1045 carbon steel, and let's just say that removing the original shaft was NOT a fun process. I had to use a 20 ton hydraulic press and a heat gun to get the old one out.


Let's just say that the addition of the 100cc motor has had AMAZING results. I expected to get over the 'cog hump' by just adding brute power but I had no idea that even at 100cc it would basically make cogging a zeroed out issue. Of course this based on the expected way I am driving this truck, which is like an overgrown rally car. I'm sure anyone who would want to crawl with a 1/5 would tell me I merely ran away from the problem by pouring torque into it instead. They would still be correct though.


This is the truck powering up on a mere 8S1P battery series chain that is 5000mAH in capacity. It is just two 4S packs wired up in series. I have so much torque even with this setup that I ran into chain skipping issues from the sheer amount of power that was loading up. I am building some chain tensioners next and this appears to be the last remaining problem before the truck is fully driveline tested out.

The full power of my "starter module" will be 8S4P, with a storage backing of 20,000mAH to drive this motor. This is eight total packs, with two groups of four each per module. Each module is four packs wired up in parallel with a crossbar.

The next logical step is to go up to 12S3P with six total 6S 10,000mAH packs each. This means two modules of three packs wired up in parallel with a crossbar. The 12S3P setup would have a storage backing of 30,000mAH which I feel is a true safer level of current protection for the batteries.

Sorry that updates are so slow. Lately I have not had much time to work on that because of the kiddo going back to school, and being a single dad kind of crimps my schedule to say the least. Don't get me wrong, i am not complaining and I love my life even though its a bit crazy. I still have found some time to work on things anyhow.

Next area of focus? The body. I can't wait, and thanks for reading!
 
Thanks Owen and Dan! I would love to make the trip once the truck is ready. My progress has been slow recently but here are a few updates anyhow:

I tried my hand at making a motor sensor system for the Hobbywing Max4 to use with outrunners other than the 70125 that it was exclusively pair with, and long story short... things did not work out. The journey here may be interesting for others so I will share anyway. I took a sensor board assembly from a 540 motor and basically desoldered all three Hall sensors on its board and then wired up extensions to them instead.


These were then wired up to a small breakout board with standard 0.100" pins, and a set of otherwise identical but different form factor Hall sensors were wired up and connected one by one to the breakout board. The motor sensor cable then connects into the sensor board and you can now see it serves nothing more than an extended sensor middleman device. Here is the board from above all soldered up and packaged inside a legacy 75MHz receiver casing:


The intent here is to get any other sensorless motor new life to work with the Max4 in sensored mode.The completed concept is not new and many others have done this before, I simply watched what others did and copied it- standing on the shoulders of giants. The next step was to machine a ring outside the motor can to properly align and adjust the Hall sensors so they are sitting 120 degrees equidistant of each other. I tested this out by wiring up a different outrunner to one of my sensored ESCs (a Quicrun) and literally using hot glue and cardboard to hold the sensors down just to prove the concept out. It worked, so the next step was to try and mount this up and test with the 50cc motor before making the ring.

Long story short... it did not work. I suspect (but cannot verify 100%) that the unused thermal sensor pin might be used to do something proprietary to get the Max4 to work with the 70125. Without a 70125 motor I cannot be certain. I tried using both latching and bipolar Hall sensors but the Max4 would not start up in sensored mode. Oh well, so this was "Plan B" and this idea was ditched in favor of the original "Plan A" - which is MORE POWER.


Pictured above is the intermediate 100cc motor that I ordered in haste as I am still waiting for my backordered 150cc. The older 50cc motor is still mounted in the truck as seen. The new motor is nothing flashy, a Turnigy CA120-150kV outrunner. Intended for airplane use, its been around for a few years and seems to be decent at its job despite having somewhat low maximum power ratings. It is seen above with its original shaft facing the "wrong" way. I machined an extended shaft for it using 1045 carbon steel, and let's just say that removing the original shaft was NOT a fun process. I had to use a 20 ton hydraulic press and a heat gun to get the old one out.


Let's just say that the addition of the 100cc motor has had AMAZING results. I expected to get over the 'cog hump' by just adding brute power but I had no idea that even at 100cc it would basically make cogging a zeroed out issue. Of course this based on the expected way I am driving this truck, which is like an overgrown rally car. I'm sure anyone who would want to crawl with a 1/5 would tell me I merely ran away from the problem by pouring torque into it instead. They would still be correct though.


This is the truck powering up on a mere 8S1P battery series chain that is 5000mAH in capacity. It is just two 4S packs wired up in series. I have so much torque even with this setup that I ran into chain skipping issues from the sheer amount of power that was loading up. I am building some chain tensioners next and this appears to be the last remaining problem before the truck is fully driveline tested out.

The full power of my "starter module" will be 8S4P, with a storage backing of 20,000mAH to drive this motor. This is eight total packs, with two groups of four each per module. Each module is four packs wired up in parallel with a crossbar.

The next logical step is to go up to 12S3P with six total 6S 10,000mAH packs each. This means two modules of three packs wired up in parallel with a crossbar. The 12S3P setup would have a storage backing of 30,000mAH which I feel is a true safer level of current protection for the batteries.

Sorry that updates are so slow. Lately I have not had much time to work on that because of the kiddo going back to school, and being a single dad kind of crimps my schedule to say the least. Don't get me wrong, i am not complaining and I love my life even though its a bit crazy. I still have found some time to work on things anyhow.

Next area of focus? The body. I can't wait, and thanks for reading!
Life comes before toys brother! Had a guy on here that did a custom build that took years. We all followed along and eventually it got finished up.
Well be here waiting for the next update even if its in another month or so. Lord knows I don't have the time I used to. Best luck with life and looking forward to your next update.
 
Sorry that updates are so slow. Lately I have not had much time to work on that because of the kiddo going back to school, and being a single dad kind of crimps my schedule to say the least. Don't get me wrong, i am not complaining and I love my life even though its a bit crazy. I still have found some time to work on things anyhow.

Good thing you live in the city that doesn't sleep!... Awesome build dude. If you ever take that thing out I know a bunch of local guys that would absolutely drool over this rig!!! They run on the Conduit btw
 
Life comes before toys brother! Had a guy on here that did a custom build that took years. We all followed along and eventually it got finished up.
Well be here waiting for the next update even if its in another month or so. Lord knows I don't have the time I used to. Best luck with life and looking forward to your next update.
Thanks for the support! Luckily I am pretty close to getting this running at a first phase of basic operation, and despite the size of the truck its a pretty simple design with a pretty low parts count for it is. I've seen some of the other custom projects people have made and they blow mine away in terms of fabrication and complexity...
Good thing you live in the city that doesn't sleep!... Awesome build dude. If you ever take that thing out I know a bunch of local guys that would absolutely drool over this rig!!! They run on the Conduit btw
Thanks! I would definitely want to take this out more when I'm done. Conduit's not too far from me, and I would love to run it on in LI as well. Hopefully I'll have more time to do this next spring.
In the meantime I've got some small updates on the truck. I made the decision to just jump ahead to improve the brakes. While the mechanical ones that come with the Raminator axles are actually designed and manufactured quite well- I had concerns during testing that they would not be enough to stop the truck with authority. Normal driving would be okay but if I am hauling or pulling a load then this is where problems would be expected. I am also spoiled by electric drive and am used to very overpowered brakes as part of my driving style.

So the decision was made to migrate to hydraulic mountain bike brakes. I went with a triplet of Shimano MT200 brakes and levers for the truck. There is one problem though- the brake discs on the Raminator are almost 4mm thick. Traditional mountain bike discs are half that or even less. I had a choice of either flycutting the discs to thin them out, or somehow expanding the brakes. After seeing how easily these can be taken apart I realized I would modify the brake caliper design instead and keep the stock Raminator brake disc thickness, keeping them stronger overall.


Aluminum spacers were turned out on the lathe to widen the working width of the calipers to an extra 2.5mm. Three spacers were needed for each caliper - two for the screw mounts and a third for the mineral oil gallery port.


This relatively low-effort fix makes it possible for me to go with a much stronger hydraulic setup. The mounting lugs were ground off and I am going to use the caliper mount holes work double duty as the mount point of the brakes, using M6 fasteners from the other side.


The brake levers have had their extra lengths cut and pull point drilled out. I will be making a bracket to mount them together side by side so they can be pulled in a common linkage from a single servo.


Test fitting one of the calipers. By deleting the original bicycle mounts and using the caliper screw hole mounts this will simplify the brake mount design.
Well that's all I have for now, thanks for reading!
 
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Hi all,
A few minor updates... the driveline is now functionally complete. I can finally start working on the body now. I actually am excited about this part...


First off are the brake levers shown here. This looks like such a kludge and admittedly it totally is! The three brakes are arranged with the front brake lever being in the middle so that it gets little or no bias when the linkage is drawn tight. This is a similar setup to when I used the mechanical brake cable pulls.

I did things the hard way by machining a completely new rear bulkhead to fit the levers and a servo behind them. The extra work was worth it, instead of trying to hack things into the existing bulkhead. It also gave me an opportunity to lower the rear axle drive input to give a more favorable universal joint angle to the rear axle.


There's been some nice wear and break-in on all of the rotors. I've tuned the modulation of the brakes to work perfectly without too much fuss. There are a number of trade-offs being made here but in the end everything works out. Follow me if you can on this crazy train of nonsense:
  • Mountain bike hydraulic brakes are meant for use with larger diameter rotors, so these Raminator units don't get to use them at their full potential.
  • BUT the stopping power of the MTB hydraulics is just far greater than the mechanical calipers.
  • The pads will wear unevenly...
  • BUT Shimano brake pads are pretty cheap and readily available as spares.
  • MTB rotors are expecting to be spun at lower RPMs so brake modulation will be compromised...
  • BUT the power delivery of a 1/5 servo is crisp and more consistent than a set of human fingers.
  • AND a radio that allows reverse exponential cleans up the feel of braking real quick.
  • ALSO the massive contact patch of the Raminator tires gives a level of stopping power that mountain bike tires just cannot touch.
Okay, now that the sugar has worn off, on to other things. I added a coilover shock to a chain tensioner to keep the motor drive chain from slapping around.


This was a brute force "engineering" hack of a solution but it works really well and is sort of fun to watch in action. I will definitely have to mount a camera here just to record this action because its somewhat addicting to watch.

Okay, now for a few clips to show how effective the braking is...



I shot these short clips before I tuned the braking with negative exponential- but felt these really drive home how effective they are. This stopped the truck on a 50% throttle launch on 8S1P like it was nothing. Now that I have brakes as intended, I feel much better about driving it around. Also with the driveline finalized I can start making covers for the chains. More driving time means I can spend more time tooling around with it to make adjustments here and there to address minor problems.

Oh well, that's all I have for now. Thanks for reading!
 
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Despite the body not being ready, I decided to take the truck for a spin to validate its chassis and basic setup. I am quite pleased with how it ran. It isn't as fast as I would have liked but I'll chalk that up to not being in an area where I could really let the truck spin up for a suitably long distance. Aside from some torque roll from launching hard it has no other bad habits. Here's some footage I shot from taking it out this morning...


This is a fun camera angle which I used to help me gauge the performance of the suspension and chassis:


This is another fun camera angle on the chassis, aimed at the front disc brake:


This put my mind at ease about how the chassis is doing, and now I can focus on getting parts like the body and chain covers done.
Thanks for reading!
 
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