[General] Fwd: Drag torque

[Rick]

The best bet is to ask the question at
http://www.facebook.com/groups/RoboCommunity/

The guys that build bots with spinning disks will be able to answer
questions related to rotational kinetic energy and provide the formulas. 

 

 

Rick Nickel
Owner,
Huntsville Computer Services
North Alabama Computer Services
www.HuntsvilleComputer.com
(256) 683-3003

 

 

 

From: general-bounces at lists.makerslocal.org
[mailto:general-bounces at lists.makerslocal.org] On Behalf Of Ethan Chew
Sent: Wednesday, January 18, 2012 11:54 PM
To: General discussion about makerslocal
Cc: Eric Chew
Subject: [General] Fwd: Drag torque

 

Good Evening,

 

       I was wondering if you guys could help an inquiring young mind.  Eric
would like to know how to calculate the drag torque of a cylinder rotating
on a shaft (wheel and axle configuration in picture attached).  He will be
applying a certain torque to rotate the assembly and is seeking a general
equation that would tell him for the certain torque what the rotational
velocity would be after a certain time, its maximum rotational velocity and
how long it would take to reach it.

       Help would be appreciated.  Thanks!

 

               - Ethan/spacefelix

 

---------- Forwarded message ----------
From: Eric Chew <ericchew24 at gmail.com>
Date: Sat, Jan 14, 2012 at 8:44 PM
Subject: Re: Drag torque
To: Ethan Chew <spacefelix at gmail.com>


Hey! 

So here's a simple picture of what I'm doing.

Pretty much, I'm trying to rotate a cylinder on an axle, as shown in the
picture. I will be applying a certain torque on it, and I wanted to find a
general equation that would tell me what the velocity would be after a
certain time and also what the maximum velocity it could reach would be and
how long it would take to reach it. 

I talked with my physics teacher, and she told me that the equation I put on
the paper would give me a general idea, but that calculating the drag torque
would be difficult and that she didn't know how to. I tried looking on my
own and found a lot of equations for drag force when something is moving,
but nothing on when something is rotating in place. Do you know of an
equation for the drag torque? Or could you help me derive one?

Thanks,

Eric Chew

 

On Sat, Jan 14, 2012 at 4:49 PM, Ethan Chew <spacefelix at gmail.com> wrote:

Hello!

 

      This is my business/technical contact.  Please use this e-mail only
for technical and business communication.  That being said, can you send me
a drawing of your device and how it operates so I may understand how it is
being loaded?

 

             - Ethan

On Sat, Jan 14, 2012 at 1:44 PM, Ethan Chew <eflyingfelix at gmail.com> wrote:

 

---------- Forwarded message ----------
From: Ethan Chew <eflyingfelix at gmail.com>
Date: Sat, Jan 14, 2012 at 1:44 PM
Subject: Fwd: Drag torque
To: Ethan Chew <eflyingfelix at gmail.com>





 

---------- Forwarded message ----------
From: Eric Chew <ericchew24 at gmail.com>
Date: Sat, Jan 14, 2012 at 10:35 AM
Subject: Drag torque
To: Ethan Chew <eflyingfelix at gmail.com>


Hey Ethan,

I was wondering if you knew how to calculate the drag torque of a solid
cylinder, given the radius, width, and mass of it, while it rotates on an
axle in the air.

Thanks,

Eric Chew 

 

 

 

 

 

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