BC-Brian
RCC Addict
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.
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.
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