If you still want to use the third Barry rubber bushing as a front

mount

this might work.

Decouple the front mount beam from the rest of the structure using

rod ends

or rubber bushings. As Vance is fond of quoting some English

engineer: "an

ounce of rubber is worth a pound of engineering." :) Sometimes you

can add

too many tubes to a space frame and wind up with undesirable side

effects

such as local bending moments in joints that lead to cracks.

Again 1/4 scale balsa stick models made from 3/16th square do

wonders when

it comes to understanding a particular space frame design and I

highly recommend

doing one.

Paul Lamar

I don't think I received your original email on this, and you didn't
include my corrected drawing in my original email. Here is my

corrected

drawing again, see if there are any errors. I added the three tubes

you

had redlined in.

Perry

Needs yet more tubes.

Paul Lamar

If you sent something out showing the additional tubes, I didn't get it.

Can you redline them in on this picture?

I did not send it out. I sent something else out but here are both along

with

the message I sent out.

The problem is the ass half is getting TOO stiff. So you have to make the

front

half stiff as well. Gets too complicated to analyze with out space frame

FEA.

Paul Lamar

Orginal message:

**************************************************************

Subject:             LEZ mount
       Date:             Fri, 31 Dec 2004 06:51:46 -0800
       From:             ACRE <rotaryeng@earthlink.net>
 Organization:             ACRE


Lots of snips......

If you still want to use the third Barry rubber bushing as a front mount
this might work.

Decouple the front mount beam from the rest of the structure using rod

ends

or rubber bushings. As Vance is fond of quoting some English engineer: "an
ounce of rubber is worth a pound of engineering." :) Sometimes you can add
too many tubes to a space frame and wind up with undesirable side effects
such as local bending moments in joints that lead to cracks.

Again 1/4 scale balsa stick models made from 3/16th square do wonders when
it comes to understanding a particular space frame design and I highly

recommend  doing one.

Paul Lamar

It appears that there are some bending issues in the upper mounts.
Make the model!!!! Vance

 
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