Author Topic: Wood Grain  (Read 898 times)

Offline pepperman42

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Wood Grain
« on: April 30, 2012, 07:46:34 AM »
I thought I read this somewhere - the woodgrain on fuselage panels always ran in the direction of the airflow. Am I imagining this or not?

Steve
I was clean,shaved and sober and I didnt care who knew it.

Offline GAJouette

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Re: Wood Grain
« Reply #1 on: April 30, 2012, 08:27:00 AM »
  Steve (Dr.Strangelove),
I don't believe that would be correct, although I could very well be incorrect. It seems to me that wood panels would have been attached with the grain running in whatever direct gave the fuselage the most strenght regardless of airflow.
Highest Regards,
Gregory Jouette
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Offline Jamo

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Re: Wood Grain
« Reply #2 on: April 30, 2012, 08:32:24 AM »
As it is plywood (with the grain of the individual layers layered differently) would it make any difference?

Offline Whiteknuckles

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Re: Wood Grain
« Reply #3 on: April 30, 2012, 09:11:57 AM »
Surely the layered construction (as James points out) of the plywood itself is where the intrinsic strength is? (I'm no engineer though...). However, could it be the case that the early understanding of aerodynamics indicated that the airflow over the fuse was 'cleaner' when the grain ran in the direction of airflow rather than at angles? I know that the ply was not bare as such.
Also, as evidenced by the awesome builds accumulating here, modellers vary the direction of the grain and I take it that that is historically correct, yes?? (which would negate the 'clean' aerodynamic question...)

Andrew
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Offline pepperman42

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Re: Wood Grain
« Reply #4 on: April 30, 2012, 12:49:52 PM »
Good points all. I dont think it was for aerodynamic reasons but more the way each sheet was formed into the fuselage shape - more for the "flexing" with the grain as opposed to bending against the grain. But as you say James, the nature of ply is that the various layers dont all run the same way. Must have been dreaming that one up......

Steve
I was clean,shaved and sober and I didnt care who knew it.

Offline ALBATROS1234

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Re: Wood Grain
« Reply #5 on: April 30, 2012, 02:00:41 PM »
seems to me whenever i have seen photos of actual craft, whether old or new photos the grain usually does run nose to tail. for no other reason that consistancy i would suppose. now, i have seen quite a few modellers vary the grain direction when modelling ww1 aircraft. but i havent seen this in photos of real planes.

Offline Whiteknuckles

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Re: Wood Grain
« Reply #6 on: April 30, 2012, 02:30:05 PM »
....but i havent seen this in photos of real planes....

That's interesting.....what do others have to say on this?

Andrew
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Offline kornbeef

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Re: Wood Grain
« Reply #7 on: April 30, 2012, 04:47:47 PM »
Of course then theres the swirly whirly pine grain often seen on Albatros aircraft, I know its grained but can be used to great effect. On the nose to tail thing I'm out until the jury decides, I've modelled both though now tend to go for the nose to tail approach.

Keith.

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Offline pepperman42

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Re: Wood Grain
« Reply #8 on: May 01, 2012, 07:18:09 AM »
the plot thickens......As mentioned the 3 ply has the middle board grain perpendicular to the outside plys so the bending aspect is sort of nulified but the photos I have gone thru indicate the outside plys do go nose to tail.

Steve
I was clean,shaved and sober and I didnt care who knew it.

Offline pepperman42

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Re: Wood Grain
« Reply #9 on: May 02, 2012, 07:12:15 AM »
So the moral of the story is nose to tail grain for all panels? Part of the fascination of these birds is the fact that the craftsmen were part engineer, part framing carpenter and part furniture maker!!!

Steve
I was clean,shaved and sober and I didnt care who knew it.

mike in calif

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Re: Wood Grain
« Reply #10 on: May 02, 2012, 08:12:21 AM »
I just caught on to this. My experience is that one always lays the ply fore- and -aft. Pfalz and Albie utilised common boat building practice(Roland too!) which runs  that way. The ply can be steam bent, and then fastened in place over formers while flexible. The formers might have some slight extra curve to allow for "spring back", which reduces tension in the assembly.

Offline Piltdown Man

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Re: Wood Grain
« Reply #11 on: May 18, 2012, 05:15:09 AM »
Steve is right to question which way the grain should run. Plywood generally has an odd number of laminations and is therefore more resistant to bending in one direction than another. My experience on 12" to the foot scale is that you have to look at the plans to see which way the grain should run. But I'll stick my neck out and say that plywood that forms the structure (rather than just being nailed on to keep the wind out) of a fuselage normally runs fore and aft.

Trevor

PS: But it does look pretty when the panels don't.

Offline pepperman42

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Re: Wood Grain
« Reply #12 on: May 19, 2012, 02:55:20 AM »
I think that all grain going front to back can look good. The key to it is making sure the grain from one panel does not "flow" into the next panel. Moving the grain up or down from one panel to the next creates the illusion of seperate panels.

Steve
I was clean,shaved and sober and I didnt care who knew it.

Offline fcmdecal

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Re: Wood Grain
« Reply #13 on: May 26, 2012, 09:42:35 AM »
The wood grain has nothing to do with aerodynamics, a piece of wood is easier to be curved in parallel to its fibers. I think the position of the wood fibers follow the direction most favorable curvature of the slab will have to suffer.