Bass wood vs sitka or Doug Fir

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Brian Amato
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Joined: Fri Aug 31, 2018 9:23 am

Bass wood vs sitka or Doug Fir

Post by Brian Amato » Sun Aug 11, 2019 2:47 pm

I've been offered some lovely 2" thick, 16' long bass wood by a friend who has been storing them for years. I'm wondering about planing and ripping them for the longerons. I have the rest of the wood (Sitka) for uprights and cross members but I'm wondering if anyone has any thoughts about bass wood?
Some of the things I've found on the web says it compares favorably.
Anybody

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taildrags
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Re: Bass wood vs sitka or Doug Fir

Post by taildrags » Sun Aug 11, 2019 11:14 pm

Brian; just looking at the Forest Products Laboratory tables that list the mechanical properties of various woods, American basswood is considerably weaker than both Sitka spruce and Douglas fir in most of the important characteristics. It is lighter than either of the other two woods, but proportionately weaker in modulus of rupture, ultimate strength in tension, and various other structurally-significant parameters. The Air Camper airframe is said to be hell-for-stout, but it's up to you to judge just how near to hell you care to build your airframe to test the validity of that saying ;o)

-Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

Brian Amato
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Re: Bass wood vs sitka or Doug Fir

Post by Brian Amato » Mon Aug 12, 2019 6:36 am

Fair enough. No basswood

VincentDunn
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Location: Salem, OR

Re: Bass wood vs sitka or Doug Fir

Post by VincentDunn » Wed Aug 14, 2019 4:59 am

Brian,
Since Basswood is both lighter and less strong you could, in theory, increase the longeron dimensions to, say, 1.25 inches square and achieve the same weight and strength os spruce. Oscar might suggest the correct dimensions to achieve spruce parity. Also, look at Western Hemlock as an alternative. I built my whole plane from W Hemlock and found it to be excellent quality and locally available here in the Pacific NW. Good luck!

Brian Amato
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Re: Bass wood vs sitka or Doug Fir

Post by Brian Amato » Wed Aug 14, 2019 6:23 am

Thanks everybody. More a case of lazy and frugal on my part than anything else. A good friend had this basswood and offered it to me.
I built the Corben Jr. Ace using nice, straight grain, Doug Fir and it was terrific. Even the FAA inspector said it was superior to much of what he sees.
We have a small but well stocked lumber yard up here in N. Michigan that stocks (for some reason I still don't understand) some lovely tight grained DF. I called a couple days ago and the guys said he has some pretty impressive looking stuff right now. I'm going out today to paw thru the stuff and see. Hope to come home with some 14' stuff for longerons.
Stay tuned...

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taildrags
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Re: Bass wood vs sitka or Doug Fir

Post by taildrags » Wed Aug 14, 2019 10:40 am

My recommendation on changing the fuselage framing member sizes is "don't do it". You'll end up scratching your head more often than getting anything done, because changing the dimensions will lead to changes in many, many other connections throughout the airplane and you'll probably be thinking, sketching, figuring, and adjusting your way through the entire build.

Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

Brian Amato
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Re: Bass wood vs sitka or Doug Fir

Post by Brian Amato » Wed Aug 14, 2019 11:29 am

I agree with Oscar. Best to follow the plans. Guys that think they have a better idea and start changing things wind up chasing their tail through the whole build. Just not worth it.

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Terry Hand
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Re: Bass wood vs sitka or Doug Fir

Post by Terry Hand » Fri Aug 16, 2019 4:01 pm

"The Air Camper airframe is said to be hell-for-stout, but it's up to you to judge just how near to hell you care to build your airframe to test the validity of that saying ;o)"

Well put, Oscar (as you typically do so well).

Have you considered where you might be able to use the Basswood in a non-structural location? Building the framework for the cowl supports as shown on Drawing number 1, for example? The mid supports for the turtledeck? I would not say that there is NO location for using the Basswood, just not as part of the structural framework.
Semper Fi,

Terry Hand
Athens GA

Brian Amato
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Re: Bass wood vs sitka or Doug Fir

Post by Brian Amato » Mon Aug 19, 2019 9:25 am

Bass wood in other areas: Good idea ......I might be able to use it in other areas. It's lovely stuff !!

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