Re: 049 test stand dont's

Morgans wrote:
> "Tim Wescott" <tim@[EMAIL PROTECTED]
> wrote
> 
>> For a motor stand I'm using a Tatone stand with a piece of 1/8" angle
iron 
>> on which the engine is bolted.
>>
>> Don't do this, unless you want some practical education in resonances.
At 
>> the 'bad frequency' (which was just a bit lower than what the engine 
>> really wanted to do) I could see the cylinder moving through a 1/4"
long 
>> arc.
> 
> Another thing you can do, until the engine sizes get really big (big
enough 
> to move a concrete block <g>) is to mount the stand to a piece of 2 X 8 
> (either using the steel between the engine mount and the wood, or not)
and 
> mount the whole thing on a 8 X 8 X 16" concrete block.
> 
> The block adds enough mass to purty much guarantee that the resonance
will 
> be too low to matter, and the wood helps even more to dampen out any
small, 
> fast vibrations.
> 
> That, plus you don't need to do anything except set your block out in
the 
> yard, and crank up the engine.
> 
> Like I said, until you go with a really big gasser, it ain't goin'
nowhere! 
> <G>

I'm pretty sure this resonance was the angle iron flexing in the stand, 
which wouldn't change much if it were on a concrete block.

I'll know more after I get the 'right' adapter built.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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