View Single Post
  #4   Spotlight this post!  
Unread 06-02-2012, 01:02
Aren Siekmeier's Avatar
Aren Siekmeier Aren Siekmeier is offline
on walkabout
FRC #2175 (The Fighting Calculators)
Team Role: Mentor
 
Join Date: Apr 2008
Rookie Year: 2008
Location: 대한민국
Posts: 735
Aren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond repute
Re: Gear ratios for launcher

Quote:
Originally Posted by Ether View Post

Has anybody posted test data anywhere that includes wheel rpm, wheel diameter, squeeze, launch angle, and distance?

I've been keeping an eye out, but haven't seen anything yet. It would be most useful as a sanity check for some of the calculations.

We took a decent amount of data with ball compression, I'll see if I can't dig that up and compile for public posting.

We're gearing for a top speed at the wheel edges of about 80 ft/s (54 mph!), since this is about double the speed of 40 ft/s that worked well for basically any shot in the near half of the field in our testing. So for a 4" wheel that's a 5:1 off of FPs (0673) and we have nearly the equivelant of 4 of them (2 FPs, 2 550s), so we're making up for lost torque (see here for more of the reasoning behind that). We're using the same 8" plaction wheels we tested with because that tread seemed to work better than others we tried briefly. I pushed for wheels smaller than the ridiculous 8 inches, but nobody ever tested anything smaller (we have screwed up ways of setting priorities, working on fixing that...) and people were worried about differences in traction with smaller wheels, we stuck with 8". The reasoning for smaller wheels was mostly weight, with a marginal benefit in how the frame could be layed out (more freedom), as well as just not having ridiculously huge wheels. But no one listens to me anyway... In any case, with our 8" wheels we have 10:1 total reduction off of 2 FPs and 2 550s in the works.