View Single Post
  #13   Spotlight this post!  
Unread 16-01-2013, 19:11
AllenGregoryIV's Avatar
AllenGregoryIV AllenGregoryIV is offline
Engineering Coach
AKA: Allen "JAG" Gregory
FRC #3847 (Spectrum)
Team Role: Coach
 
Join Date: Jul 2008
Rookie Year: 2003
Location: Texas
Posts: 2,551
AllenGregoryIV has a reputation beyond reputeAllenGregoryIV has a reputation beyond reputeAllenGregoryIV has a reputation beyond reputeAllenGregoryIV has a reputation beyond reputeAllenGregoryIV has a reputation beyond reputeAllenGregoryIV has a reputation beyond reputeAllenGregoryIV has a reputation beyond reputeAllenGregoryIV has a reputation beyond reputeAllenGregoryIV has a reputation beyond reputeAllenGregoryIV has a reputation beyond reputeAllenGregoryIV has a reputation beyond repute
Send a message via AIM to AllenGregoryIV
Re: Prototype Small Wheeled Shooter

Quote:
Originally Posted by Ether View Post
1:1 BAG at free speed* is 14,000 rpm. With 2 7/8 dia wheel that's 120 mph tangential speed. With no slippage that's 60 mph.

If the frisbee is not exiting that second wheel at 60 mph it might be because it is slipping.

So, either:

1) crank down the speed of that second wheel a bit to stop the slipping and get a higher exit speed, or

2) crank up the speed of the first wheel, which is presently only 1930 rpm, which translates to 16 mph tangential velocity or 8 mph exit speed. A higher exit speed from the first wheel means a higher entry speed into the second wheel, which may reduce the slipping in the second wheel and give a higher exit speed

* I realize that due to windage and vibration it will be less than that
Tonight's test has two BAG motors 3:1 and 1:1 (instead of a 550 and a BAG motor) and we're getting 30-35 feet from 2 feet off the ground and 0 degrees of incline. We also moved the blue wheels on the front and it seems slightly better. We're hoping that the harder wheels won't be eaten as fast as the green soft wheels.
__________________

Team 647 | Cyber Wolf Corps | Alumni | 2003-2006 | Shoemaker HS
Team 2587 | DiscoBots | Mentor | 2008-2011 | Rice University / Houston Food Bank
Team 3847 | Spectrum | Coach | 2012-20... | St Agnes Academy
LRI | Alamo Regional | 2014-20...
"Competition has been shown to be useful up to a certain point and no further, but cooperation, which is the thing we must strive for today, begins where competition leaves off." - Franklin D. Roosevelt