BC-Brian's Real life Unlimited MOW with a dash of something crazy

[BC-Brian]

Had a great time in Moapa Vallley at worlds. It was damn hot but the rigs held up. The MOW got a chance to play pretty much every day and held together a lot better than I thought a 3D printed rig would. Going to be looking into new ways to build the gearbox and continuing to harass people for a sensored motor.

Since details were sparse I will fill people in.

The MOW (Motor on wheel) was a concept I had been working on for a little over 2 years. It started as a Pro Rig but found it challenging to fit everything inside a 2.2 wheel like I wanted. With the creation of the Unlimited class and a hint to look at short course wheels I all of a sudden found the room I needed inside the wheel, 2.2" at the face, but the inside is 3.0".

Each wheel has a gearbox made up of modified XR10 gears (thanks to JSlick and Purpt8r for their gear donations) configured as a 25:1. Powering the system is a pretty straightforward 1000kv 22N12 quad copter motor. Calculations put it at ~17mph with a max torque of 6.4 ft-lbs at each wheel (more on that later). Modified voodoos round out the traction system for the crawler.

Each gearbox weighs in at 143g and the total weight of the rig, ready to run is 1865 g's (4.1lbs).

The knuckle was incorporated into the gearbox housing and some plain ole ST Racing Chubs would work well mounted to a 13mm Dia carbon fiber tube to act as the cross brace (since there is no real axle let's not call it that).

Another 3D printed part would act as the mounting system for the entire axle, lower/upper link mounts, battery tray, servo mounts and shock mounts all incorporated into one part. I was pretty concerned that this would be the first thing to break but it held up very well to some light bashing

The front steering rod is something new for this rig. It is made from carbon fiber plates and uses sandwich construction to hold the ball end captive between the two plates.

The Chassis itself is also 3D printed. I was made in two halves and is seam welded down the center. Housed inside the chassis is a 64mm ducted fan from an electric jet. With the flip of a switch it spools up to ~15000 rpm and provides just under 1 pound of thrust out of the top of the truck. This will push the truck into the rock as you are driving it. See a nasty side-hill of a very steep climb. Fire up the fan and it will help keep the rig planted. This was neat in concept but REALLY awesome to see it work in real life.

Thanks to Castle Creations the System is powered by 4 Mamba Micro X controllers for the drive motors, a BEC running the front servo and a Talon 35 controlling the Ducted Fan and powering the rear servo. Two Hitec 7950TH, a Spektrum AR9020 receiver and a 3S 1100mAh Battery round out the electronics.

In addition to the fan and everything else this rig has some other advantages that include:
A very low CG. Each wheel/gearbox assembly has a CG 10mm below the wheel axis.
Massive clearance. The height clearance to the cross tube is the same as the height clearance to the chassis skid which is over 86mm (3.3").
Optional independent motor control. This is a feature that I am actually not using. I could not figure out an intuitive way to control them all individually even with an 18 channel radio. It is setup to drive like my MOA with one change, i have a switch that will turn off the rear left or right motor providing me with a pretty sweet cutting break. Put together with rear steer gets a very tight turn.














Enough Glamour shots, time for some close ups.

[crawlinghulls]

That thing is awesome

[Jslick]

So glad to see a bunch more pics. Glad I could help out in a small way make this thing go. It is truly an awesome rig.

[Jcplante]

Nice work on this! I had no idea you had it in the works. I have seen a few attempts at making a MOW but none that looked promising. I cant wait to see it perform at a comp. Best innovation since the moa "shafty" at last years worlds! Awesome rig man!

Sent from my ALCATEL ONE TOUCH Fierce using Tapatalk

[ROWDY RACING]

Wonderful!

[BC-Brian]

Originally Posted by Jcplante

Nice work on this! I had no idea you had it in the works. I have seen a few attempts at making a MOW but none that looked promising. I cant wait to see it perform at a comp. Best innovation since the moa "shafty" at last years worlds! Awesome rig man!

Sent from my ALCATEL ONE TOUCH Fierce using Tapatalk

Thanks man, I kept it under the radar to be a surprise for worlds. I will be bringing it to the comp next weekend.

[JohnRobHolmes]

Here is an up close and personal look with this rig, it was quite amazing to drive even with the sensorless motors! It took me back about 8 years to hear the outrunners bleep to life. Thanks for putting the effort into this rig Brian, you executed all my ideas I've wanted to do for years! 2008 I attempted to make MOW and didn't pull it together, I still have all the gears and raw delrin laying around, sheesh!

https://youtu.be/fy2yfw1dWcA

[ittybitty]

Wheres the in action videos???????

[Dostradamas]

Makes me reminisce on this


Not the look, but that executed ideas change the future.

Well done.

What's next Hovercrawlers?

[BC-Brian]

Originally Posted by ittybitty

Wheres the in action videos???????

Thanks for posting that video from youtube on here JRH, I watched it this morning but have been swamped all day.

Josh at Extreme Scale Performance took some video of it Crawling. He has 80 gigs of video to go through from the weekend but I or he will get it on here as soon as he has it ready. Big thanks to him because I totally blanked on getting any video pf it driving for myself.

I am going to try go get out this weekend and play with it a little bit so I will try to get some of my own footage too.

[Jcplante]

I cant believe nobody has thought of using the ducted fan in a crawler yet. I have had one sitting on my bench for over a year. I wanted to use it for something but could never figure out what. Its right next to my 2.2p rig and I never thought of it lol. Great idea!!

Sent from my ALCATEL ONE TOUCH Fierce using Tapatalk

[Raptorn]

Mad respect for the 3D printing and engineering! I bet it feels amazing to see it go from CAD model to running.

[BC-Brian]

Originally Posted by Raptorn

Mad respect for the 3D printing and engineering! I bet it feels amazing to see it go from CAD model to running.

You should ask Robbob what I looked like. I met him at 10:00am after getting less than 3 hours sleep to complete it. I had a giant grin from ear to ear just to see it drive on grass in a straight line, let alone having rear steer, and a fan.

Can never dwell though, next is getting better motors and re-designing gearboxes to be bulletproof.

[JohnRobHolmes]

Originally Posted by Jcplante

I cant believe nobody has thought of using the ducted fan in a crawler yet. I have had one sitting on my bench for over a year. I wanted to use it for something but could never figure out what. Its right next to my 2.2p rig and I never thought of it lol. Great idea!!

Sent from my ALCATEL ONE TOUCH Fierce using Tapatalk

I'm sure many have thought about it, I know I have for at least 5 years. But Brian is the first to do it, which is the important part!

[josh6575]

Super cool Brian. It was fun to see something different built.

[BC-Brian]

Originally Posted by josh6575

Super cool Brian. It was fun to see something different built.

Thanks Man! It was fun to build it, Bringing it to Worlds was motivation to finish it.

I was hoping to get some time with it on the rocks this weekend but my wife had other plans for me (Clean the house).

In the mean time here are a few photos from the build.

Gearbox Housing inside the Renegade Shortcourse Wheel (Pre Pink Paintjob). Also worth noting, the gearboxes with motors weigh 143g each.


A pair of Castle Creations Micro X Sidewinders smashed up good.


Ducted Fan installed in the Chassis before the two chassis halves were welded together.

[Curcal]

are the mirco x's sensored esc's? cant tell if there's a plug for that or not after the shrinkage....

[Krawler Kev]

Originally Posted by Curcal

are the mirco x's sensored esc's? cant tell if there's a plug for that or not after the shrinkage....

I believe that they are Curt.

[BC-Brian]

Originally Posted by Curcal

are the mirco x's sensored esc's? cant tell if there's a plug for that or not after the shrinkage....

Yea Curt, Like Kevin said.. They are sensored controllers. I don't have sensored motors yet but once I do they will get wired into those 4 bad boys.

[jason]

I love to see this innovation, very cool, can't wait to see some video of it on the rocks.