Holmes' Mid Super (Standard Unlimited) Vehicle build

[JohnRobHolmes]

Time to start work on the newest class of rig that really has me excited about building again! I have no clue where this may go, since the only real constraint is that I have to fit through 16" gates. I will focus on this rig being highly capable and primarily tuned for Classic Comp style courses, with a removable camera mount to give it a payload option and utility beyond just competing.



So, when the world is your oyster and you have practically no rules to guide a build, where to start? 2007 is where I'm going to start, it is when I first considered a motor in wheel concept. The many hurdles to make it happen are not so different 8 years later, but my machinery and experience is far improved.


I also have a worker that is exclusively my right hand man and not involved in daily operations, so when it comes time to watch the mill run or assemble parts, I have an extra set of hands to speed it up or take over when my time runs too short. Include the rest of the crew at HH and it's like having a small posse working on my toys, totally a mind trip for me every day.




I'll add some real tech once parts start floating in. For starters, I'll be using the link mount locations of a berg so that suspension geometry isn't starting from scratch.

[MountainStorm]

Subbed. Less Rule = More Cool.

[JohnRobHolmes]

Ordered some Mad Torque gears today for in-wheel gearboxes. Also have a few other gearboxes and gearmotors coming this way. I'll be trying to shove things into a 2.2 rim, but if I need to cut some custom rims it won't be the end of the world.



Probably going to use a Puller 400 in each wheel because it will be easy to make and easy to control. But, there is also the option of sensored outrunners if size becomes an issue.

[Tgreer]

I would order some of the plastic gears, they are much stronger than you think. If anything you could for sure run them in the rear with no problem. My small metal gear broke before one of the large plastics gave out!

[JohnRobHolmes]

I was wondering about the quality for how cheap they are. thanks for the tips! Now if I could only find my old stash of berg gears too. Seems nobody has stock right now except the v2 versions and they don't seem to have lower gears included.

[MountainStorm]

Have you considered machining wheels into the outer rings of a planetary gear? Then you could have a compact reduction.

[JohnRobHolmes]

Yep, have certainly considered it. I have a few wheels like that already that are scrapped from hubmotors. Don't want so much rotating weight and I don't want the motor on centerline for my own rig. If weight wasn't a concern I would just throw small geared ebike hubmotors on the corners. My goal is to keep everything under 6 pounds and minimize rotating weight, preferable under 5. That is most easily achieved with spur reductions.



There are a few easy paths to make a MOW rig, but my goal is to be competitive with an MOA in power to weight, strength, and center of gravity. Pretty much excludes using hubmotors and planetaries.

[FLOKI-81]

where do you shop from to get so low prices???
I have never seen that checkout on any rc-web store before..
Please let me know,,,

[JohnRobHolmes]

hobbypartz, the nitrorcx.com or whatever sister site.

[JohnRobHolmes]

Gears arrived. Plenty of room for a gearbox and puller inside a short course wheel! Probably go the route of mini sensored outrunners so it tucks inside the wheel fully.

[josh6575]

Mini sensored outrunner! I can't wait to see this.

[JohnRobHolmes]

I've been building them for a UAV company for a few years now. Each one takes about ten hours of labor, so I'm looking at a pretty big effort unless I go the lazy route and just hack a sensor board onto something off the shelf.

[josh6575]

Got any pics of the ones you have been building for them?

[JohnRobHolmes]

A few in my shop thread, here's one from my phone. About 3 ounces, the side you can't see has a hunk of a prop mount.


Next week we will be running another batch of them, so I might make my own flavor while the machine is set up.

[josh6575]

What are the dimensions of that motor?

[JohnRobHolmes]

About 1.1" x 1.1"

[josh6575]

Wow, that is tiny.

[youngblood]

Most excited I've been for a fresh build thread in years.

Please keep up the progress!

[JohnRobHolmes]

Had a chance to run some proto housings this week that could make nice light crawler motors. About 62 grams active weight, not including sensor board. They make about the same torque and 2x the continuous power as a puller 400 that's around twice the weight. So 4 motors won't weigh more than 2 of what I'm used to. Bearing tube is still kinda porky.

[JohnRobHolmes]

Housing parts got back from anodozing and black oxide a few weeks ago. Magnets and such here too. In a few weeks after worlds and I finish an OEM project I'll be able to get cracking on motors.