View Single Post
  #11   Spotlight this post!  
Unread 28-02-2011, 22:51
Ian Curtis Ian Curtis is offline
Best Available Data
FRC #1778 (Chill Out!)
Team Role: Engineer
 
Join Date: Feb 2005
Rookie Year: 2004
Location: Puget Sound
Posts: 2,521
Ian Curtis has a reputation beyond reputeIan Curtis has a reputation beyond reputeIan Curtis has a reputation beyond reputeIan Curtis has a reputation beyond reputeIan Curtis has a reputation beyond reputeIan Curtis has a reputation beyond reputeIan Curtis has a reputation beyond reputeIan Curtis has a reputation beyond reputeIan Curtis has a reputation beyond reputeIan Curtis has a reputation beyond reputeIan Curtis has a reputation beyond repute
Re: Arm swings when turning, how to brace it?

Quote:
Originally Posted by MCahoon View Post
From my experience, the 1x1 I get at Home Depot here is 1/20 in. wall. Light for an arm by itself, but when used to stiffen it could be sufficient.
It likely is. When I took Aero Structures last semester, one of our homework assignments was meant to drive home the fact that a closed section (like a tube with a square or circular cross section) is significantly more resistant to twist than an open section (imagine a tube after you've run a sawzall down one side).

You can show that for the same stress a circular thin walled closed structure (like a length of tubing) can carry 60x the torque of the equivalent structure with a slit down one side.

In layman's terms, you get about 60x less twist once you close the structure. Tubing is your friend.
__________________
CHILL OUT! | Aero Stability & Control Engineer
Adam Savage's Obsessions (TED Talk) (Part 2)
It is much easier to call someone else a genius than admit to yourself that you are lazy. - Dave Gingery
Reply With Quote