DPRG mailing list archives: [DPRG] RE: .Parallax Robot

Sun Jan 6 02:29:14 CST 2008

Hi Jeff,

It sounds like we have a common design goal, an APU to allow extended run
time / loiter for long haul robotics that doesn't keep the neighborhood
children awake when returning home on a late summer evening...   Odd that
I've never made it to a TCRG meeting or competition and I have made it to a
DPRG competition.   The Oddness comes that I live only a few hours south of
you guys.

The APU work is definitely in the plans for my Sojourner robot project.   I
had decided to develop it as a tow behind cart for use with ProtoBot and
then to integrate it on the Sojourner platform.

I don't know if you still attend TCRG meetings but possibly we should pick
one that I could head up for so that we can chat.   It is just far enough
that given the Thursday night timing I'd have to take a Friday off and leave
work extra early on Thursday to make it...  I am headed out to CES this week
(this morning) so I'll be a little slow on e-mail responses during the
week...

-Kenneth

-----Original Message-----
From: dprglist-bounces at dprg.org [mailto:dprglist-bounces at dprg.org]On
Behalf Of Jeff Sampson
Sent: Sunday, January 06, 2008 2:08 AM
To: dprglist at dprg.org
Subject: [DPRG] RE: .Parallax Robot

Hi Kenneth, Ron and Glenn,

This talk of quiet small engines got me curious. I have made three
attempts at a gasoline power generator.
First attempt:
http://www.sampson-jeff.com/eep/eep3.htm
Second attempt:
http://www.sampson-jeff.com/eep/eep9.htm
Third attempt:
http://www.sampson-jeff.com/rsoh/031024/
http://tcrobots.org/mtgpics/2003/0312.htm

The first and second versions actually ran. Number one was too big.
Number three sheared a steel pin on the motor and the engine developed
mechanical problems. But yes, they were both too loud.

So I did some quick searching and found various links to tuned exhaust
information, animations and programs to do calculations.

This page has purchased software and a link to free progam:
http://www.bevenyoung.com.au/mota.htm

The last message on this page gives links to wikipedia and How Stuff Works:
http://www.motoredbikes.com/showthread.php?t=4352

The wikipedia link has animations and software and links to other sites:
http://en.wikipedia.org/wiki/Expansion_chamber

This link from wikipedia has silencer tuned exhaust:
http://seniordesign.engr.uidaho.edu/2003_2004/SPR/snapshot%20-%20exp.%20cham
ber.htm

So these are some good places to start if anyone is interested in using
gas engines for robots. It will give me something else to work on, if I
run out of other things to do. ;-)

--
Jeff Sampson
http://tcrobots.org/members/jsamp.htm

Kenneth Maxon wrote:

> One company out there that makes this sort of mufflers that can be
modified
> to tune for standing wave noise cancellation can be found at the following
> link.
>
> http://davisdieseldevelopment.com/muffler/giant.htm
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