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Strength by species

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mcrae0104

Well-Known Member
Supporting Member
Joined
Oct 27, 2009
Messages
5,006
Location
KEIK (CO)
From time to time, the relative strength of wood species is discussed here at HBA. I recently ran across the following video from Fisher Flying Products.



Below I have transcribed their results, which I find questionable. Although the weight of the test samples is mentioned, interestingly, there was no mention of the relative strength-to-weight ratios. There are some obvious problems (consistency in placement of the load and small sample size) although I cannot account for all of the tests exceeding Sitka Spruce's strength-to-weight ratio (pine in particular). If Northern White Pine truly performs 30% better than Sitka Spruce, I expect the aircraft industry never would have used Sitka.

SpeciesSpecific gravityLoad carriedUltimate stress (Fb)Strength-to-weightComments
Sitka Spruceas-tested:
ANC-18:
0.415
0.40 avg., 0.36 min.
41.55 lb
37.30 lb (calculated)
10,471 psi
9,400 psi
107%
100% (control value)
result closely matches book value when corrected for higher specific gravity
Northern White Pine
Eastern White Pine
as-tested:
ANC-18:
0.395
0.38 avg., 0.34 min.
47.85 lb
34.52 lb (calculated)
12,059 psi
8,700 psi
130%
97%
ANC-18 values listed are for EWP; both NWP & EWP are Pinus strobus
Yellow Poplaras-tested:
other source:
0.519
0.37 - 0.59
50.90 lb
40.47 lb (calculated)
12,828 psi
10,200 psi
105%
83%
not listed in ANC-18
Douglas Firas-tested:
ANC-18:
0.447
0.51 avg., 0.45 min
46.45 lb
45.63 lb (calculated)
11,706 psi
11,500 psi
111%
96%
performed 15% better than expected despite low specific gravity
 
Last edited:
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