Event Horizon Design Update

In the past few weeks, I have overhauled almost every aspect of Event Horizon with the goal of making it more robust (Silent Spring proof). Hopefully, this will give a good overview of what I changed.

Drum

The drum is where most of the issues from the original design originated. Here are the changes made:

• Added pin between sleeve and motor mount piece: This should prevent these two pieces from rotating in unfortunate ways and shearing the wires.
• Added internal steel nut strip: If the teeth get ripped out, it won't trash the drum (as much). The nut strip also acts as a keyway for the piece attached to the output of the motor.
• Removed clamping piece for motor output and replaced with a plate bolted to the face of the motor: The primary motive for this was reducing weight, but it also leaves more space inside of the drum for other modifications.
• Moved idler bearing from drum to frame: Making those press fit pieces was a pain.
• Added retaining rings and washer to idler shaft: This constrains the bending of the frame by putting the drum in tension when the two main frame pieces are pushed apart. I believe this will help prevent Silent Spring-induced explosions.
• Switched to a shielded bearing for the motor side: The open bearing got filled with dirt and other crap, which made it very stiff. It is best to avoid having the bearing filled with dirt.
• Added a nub in the frame piece that matches the wire cutout in the motor mount sleeve: This constrains the rotation of the drum and prevents it from pulling its own wires out as in the Gemini match at FI.
• Switched to a continuous steel blade for a tooth: It is inset into the drum and should be much tougher. I may not bother with this if I don't have enough time to do the machining.

Washer added to the idler shaft

Keyway nub to prevent rotation

The internals of the drum

Full render of everything

Drive Base

Most of the changes to the drive base were aimed at weight reduction. Changes made:

• Switched to brushless motors: They are lighter and should be faster. I'm planning on using these: https://hobbyking.com/en_us/turnigy-park300-brushless-outrunner-1380kv.html
• Back wheel is no longer direct drive: This improves the space situation and some reduction is probably necessary for the new motors.
• Front and back wheels are now different sizes: Improves packaging.
• Aluminum hex hubs are switched for nylon: Weight savings.

New wheel configuration

Frame/ Armor

I made a lot of changes to the frame aimed at improving strength.

• Re-worked front plate mounting: Should be less prone to screws ripping out, etc.
• Extended belly pan forward: This will brace the frame further toward the front, helping to prevent the main plates from buckling.
• Switched from finger joints to pins to locate center plate: Fewer giant cutouts = less bad things.
• Moved belly pan holes: I moved holes to places that do not have as many holes, rather than just ignoring their existence. This should reduce the likelihood of catastrophic failures of the frame members.
• Reduced angle of side armor: I did not find myself needing it at all at FI and the weight savings are probably worthwhile.
• Removed middle armor support: The fewer holes the better and, again, I didn't really need the side armor.
• Switched to aluminum top plate: It should be stronger (and look better) and I think I have the weight.

The new system for the front corners

What the inside looks like now (I didn't bother modeling the motors)

Extended belly pan and holes strategically placed to avoid other holes

Other Thoughts:

Hopefully I will be able to manufacture this over winter break. While there are changes that I probably will not get around to, I suspect this version will be much more competitive than the last. Some experimental things, like the brushless motors may end up not working, in which case I will switch them out for more known quantities.

For anyone interested, here is a (rough) bill of materials: https://docs.google.com/spreadsheets/d/1VzffXAeI5nw5pdMJEc_gqofo4VOdaDqT6vaQEu75xT0/edit?usp=sharing