Date: Fri, 8 Aug 2008 16:39:43 -0700
Reply-To: Mike Elliott <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike Elliott <camping.elliott@GMAIL.COM>
Subject: Re: [NVC] Engineers: quick and cheerful vibration analysis?
In-Reply-To: <86E9B334-591E-4A7C-ADA6-8EB0CFAC5D4C@comcast.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Mr B-Z,
I have been sorting and packing for the past three months. I'm rounding
the last turn of the racecourse, and am--even as I write this--taking a
well-deserved break. This is like packing for a long backpacking trip, or
a camping trip: I make lists, I sequence things. I overprepare and
overthink things, but I'm usually pleased that I seldom forget anything or
bring more than I need. I am, in short, ideally-suited to pack up a house,
a family, and a business, and move them, my stuff, and myself 1,000 miles
while craftily leaving the hard work (loading the ginormous 26-foot Penske
truck) to wife and family. Admire me, gentlemen. As you see, the way I do
things, I leave plenty of time to wonder about The Big Things, like this
dead horse.
--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus -- NOW SOLD TO THE BUYER OF OUR HOUSE
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR
On 8/8/2008 4:26 PM Tom Buese wrote:
> Mr. Squirrel,
>
> I can't believe you have time to beat this issue to death when you
> are leaving in 2 days? You must be completely packed & ready to go?
>
> LOL,
>
> Mr. BZ
>
>
> On Aug 8, 2008, at 5:02 PM, Mike Elliott wrote:
>
>> Well. Yes. Of course. One /could/ use such a *sniff* low tech
>> approach.
>> One might as well plant a small boy back there with a video camera,
>> Blair
>> Witch-style, and review the tapes later.*
>>
>> There is something about your solution that I like: it appeals to
>> my inner
>> R. Goldberg. But my inner Mythbuster (read: Grant Imahara) wants
>> accelerometers and graphs.
>>
>> I, personally, would combine your approach with my approach
>> (subjective
>> ball-watching v geeky graphs and stuff AND would add to it some
>> means to
>> inflate/deflate the tires remotely while in motion as well as sense
>> and
>> report back sidewall temperatures. I'm telling you: with sufficient
>> funding this could quickly mushroom into a completely absurd project!
>>
>> ====================
>>
>> * Actually, if that wasn't so darn dangerous and illegal, it would
>> be a
>> great way to evaluate tire pressure v ride harshness!
>>
>> --
>> Mike "Rocket J Squirrel" Elliott
>> 71 Type 2: the Wonderbus -- NOW SOLD TO THE BUYER OF OUR HOUSE
>> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
>> 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
>> KG6RCR
>>
>>
>>
>> On 8/8/2008 9:41 AM Jim Akiba wrote:
>>
>>> For what you're trying to do, software, sensors and data are way
>>> overboard I think. Match the solution to the problem... you simply
>>> want to be able to verify that at X tire pressure you do or don't
>>> have
>>> an additional level of "bounciness" whatever that means correct?
>>>
>>> What not just grab a cheap video camera, some bungees, a plastic wide
>>> mouth jar big enough for a tennis ball, a ping pong ball, and a
>>> softball for example(you might need something much heavier/lighter
>>> depending on the displacement and frequency of bounce). Put the tires
>>> at X pressure, write that on a piece of paper and "show" this to the
>>> running camera(to link that tire pressure with the video with
>>> certainty) that is now strapped to the trailer and recording the ball
>>> in the see through plastic container. Ride in a set path that you
>>> will
>>> repeat at whatever speeds you would like. Concentrate on road safety
>>> and consistency in driving. Change the tire pressure a few times and
>>> repeat. Simply watch the tape, and "see" what you can see... You
>>> could likely run this test and have an idea of what you want in the
>>> same amount of time it would take to track down a good sensor for
>>> cheap, install the software, run the test, and analyze the data.. and
>>> I'm almost 100% certain that interpreting the simple visual data will
>>> be much more intuitive for your average bear than raw numbers...
>>> especially if you aren't sure of what range of displacements and
>>> frequencies you're starting with(which you would really need to
>>> ballpark to even pick the correct sensor)
>>>
>>> Hope this helps,
>>>
>>> Jim Akiba
>>>
>>> On Wed, Aug 6, 2008 at 12:06 AM, Mike Elliott
>>> <camping.elliott@gmail.com> wrote:
>>>> This is a question for the engineering geeks here.
>>>>
>>>> Say you were towing a little trailer behind your Vanagon. Say
>>>> that the
>>>> trailer had a rudimentary suspension consisting only of leaf
>>>> springs. Say
>>>> that this trailer also had tires, the pressure of which could be
>>>> adjusted:
>>>> higher pressure results in a harsher ride, while lower pressure
>>>> results in
>>>> a softer ride. Say you wanted to determine the optimum pressure
>>>> of ride vs
>>>> tire squishiness but were unable to find a small boy to ride in that
>>>> trailer to report back about smoothness of ride v tire pressure
>>>> while the
>>>> experiments were being conducted, so lacking that small boy, your
>>>> thoughts
>>>> naturally turn to instrumentation. Okay, so say you had a laptop
>>>> computer
>>>> (WinXP) which could ride in the passenger seat, and /three/
>>>> business days
>>>> in which to acquire the needed sensor (accelerometer?) as well as
>>>> the
>>>> software to display the ride bounciness.
>>>>
>>>> Could it be done?
>>>>
>>>> --
>>>> Mike "Rocket J Squirrel" Elliott
>>>>
>
>
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