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-   -   Triangle Stock? (http://www.rcuniverse.com/forum/questions-answers-154/11246213-triangle-stock.html)

JH313 09-30-2012 01:56 PM

Triangle Stock?
 
I am rebuilding a plane and wondering, is there a difference between triangle stock and a regular "rectangle" piece of wood of the same size and material?
Thanks.

RCPAUL 09-30-2012 02:02 PM

RE: Triangle Stock?
 
Triangle stock will have half the weight!

tailskid 09-30-2012 03:09 PM

RE: Triangle Stock?
 
That's about it!

+1

da Rock 09-30-2012 04:01 PM

RE: Triangle Stock?
 
There is more difference than weight.

The way I look at the square stick I'm going to use for triangular bracing is that the stick will provide TWO triangular strips.

sebo 10-01-2012 12:11 AM

RE: Triangle Stock?
 


A SQUARE STICK WILL PROVIDE MORE STRENGTH BECAUSE THERE IS MORE WOOD GRAIN INVOLVED....THE NARROW END OF A TRIANGULAR STICK HAS VERY LITTLE STRENGTH WHEREAS A SQUARE STICK WILL PROVIDE MORE STRENGTH BECAUSE OF THE AMOUNT OF EXTRA WOOD AND GRAIN SUPPORTING THE AREA THAT WOULD BE SKINNY ON THE TRIANGULAR PIECE.
TRY BREAKING A TRIANGULAR STICK AND THEN A SQUARE STICK. SQUARE WINS......YOU DON'T USE MUCH TRIANGULAR STOCK IN AN AIRCRAFT ANYHOW. NOT MUCH WEIGHT INVOLVED THERE. IF YOU ARE ADDINGSTOCK JUST TO GIVE YOURSELF SOME SURFACE AREA TO ADHERE COVERING TO, USE TRIANGULAR; STRENGTH ISN'T AN ISSUE....JUST MY OPINION..</p>

beepee 10-01-2012 12:28 AM

RE: Triangle Stock?
 
sebo,

What you say is true, but you are ignoring the stress riser at the edge of the rectangular stock. This will contribute to fatigue in the base material at the edge. Triangle stock having a bit of flexibility at that edge will not cause such a concentration of stresses.

In the end we are not talking about much weight, or failure potential. I doubt anyone has recorded a failure caused by either installation.

Do what you like either way.

Bedford

sebo 10-01-2012 01:26 AM

RE: Triangle Stock?
 


Understood...I do agree with you....never thought of it that way...I learn something every day.....Thanks.</p>

KW_Counter 10-01-2012 04:53 AM

RE: Triangle Stock?
 
Beepee,

Could you please explain this further?

Thanks,
KW_Counter

jaka 10-01-2012 07:17 AM

RE: Triangle Stock?
 
Hi!
Triangle balsa is used in some places and square balsa is used in some places...what is it you want to know?

da Rock 10-01-2012 01:00 PM

RE: Triangle Stock?
 
In most uses, triangular stock is there to reinforce a joint. It's real value is in the area that borders the seam between the two plates.

Ever see anyone use triagular spruce? or any other hardwood? No? I don't think I ever did. And a lot of times, the stock used was medium balsa. No attempt at all to put real strong wood in because it really wasn't being put in to provide much other than joint seam reinforcement.

carrellh 10-01-2012 01:39 PM

RE: Triangle Stock?
 
Quote:

you are ignoring the stress riser at the edge of the rectangular stock. This will contribute to fatigue in the base material at the edge. Triangle stock having a bit of flexibility at that edge will not cause such a concentration of stresses.
If you slightly round the corners, will it relieve the stress riser?

rlipsett 10-02-2012 02:07 PM

RE: Triangle Stock?
 
triangle stock is good for having a prebeveled surface for control surfaces

beepee 10-04-2012 11:51 PM

RE: Triangle Stock?
 
KW Counter,

I will try to explain ...

Fatigue failure appears at areas of concentrated stresses. At the outer edge of the rectangular stock, stress in the base material is concentrated more so than the tapered edge of triangle stock(mostly from vibration effects).

This is more important for the anally retentive such as myself than for real model builders. All of my birds have died from catastrophic failure before fatigue has set in.

Bedford

beepee 10-04-2012 11:53 PM

RE: Triangle Stock?
 
KW Counter,

I will try to explain ...

Fatigue failure appears at areas of concentrated stresses. At the outer edge of the rectangular stock, stress in the base material is concentrated more so than the tapered edge of triangle stock(mostly from vibration effects).

This is more important for the anally retentive such as myself than for real model builders. All of my birds have died from catastrophic failure before fatigue has set in.

Bedford


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