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#1
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![]() The alternate wood I'm using has been australian queensland hoop pine. I found the batch I had a bit brash (a timber term meaning brittle short grained wood) so I was on the lookout for something a little safer for use in my Turbulent. well for the structural bits anyway. Australia's equivalent of Home Depot is Bunnings hardware. The stores are layed out as an exact clone of the american stores, but that is bye the bye. What I discovered in Bunnings one day was some extremely knotted planks of some yellowish wood. between the bazillion (a huge number) of knots was some amazingly fine grained timber. about 0ne ring per millimeter. the wood felt quite reasonable for weight so I bought a plank to experiment with. At this stage I had no idea what the wood species was. the stuff had a weedy smell when cut. it steamed easily and seemed to glue with epoxy really well. I used the straight grained pieces for the turtledeck bows of my first Turbulent fuselage. I experiemented some more with the remaining wood and couldnt fault it as a construction timber. I had a brainwave one day and hunted out the receipt off the floor of the car. alaskan yellow cedar was what the receipt called it. I had visions of weedy little trees in wind swept tundra being raped over by alaskan timber harvesters :-) I discussed the need to test the wood to determin its strength with an aero engineer friend. the next night he sent me the full design strength specs for the wood. having never heard of it before, this stunned me. I did some google searching and discovered some truely interesting facts regarding alaskan yellow cedar. the weedy smell only occurs when the wood has a high moisture content. when the wood is down at moisture contents suitable for aircraft use the wood is odourless. what a useful property an indicator of useful moisture content is. Trees have been discovered in forests that have no insect or microrganism attack even after standing as dead trunks for 150 years. It turns out that alaskan yellow cedar is rated as the softwood most inherently resistant to attack by bugs. another really useful property. I discovered an early aeroengineering text that gave comparitive rundowns of alternative woods to the ubiquitous Spruce. Alaskan yellow Cedar is rated as a highly shock absorbent/resistant wood sutiable for the most arduous structural use, which is the very opposite of brash timber. the thing that floored me though was the reason why spruce was selected as the wood of choice, it wasnt spruce's properties, it was just that there appeared to me more millable timber available. Alaskan yellow cedar, far from being a lower grade alternative wood to spruce, is actually a better timber in a number of it's properties. I was amazed. an alternative timber selected on a hunch turned out to be a winner. My second attempt D3 Turbulent is shaping up to be a pearler of an aircraft in Alaskan Yellow Cedar and Qld Hoop Pine marine ply. Dont knock some of those alternative timbers. Some mean that the drying up of spruce is an artifact of history, not the end of timber aircraft. ....which is good 'cause timber aircraft are wonderful building experiences. Stealth (not a single nail used in construction) Pilot btw my rape picture turned out to be a vivid imagination. there are huge stands of majestic alaskan yellow cedar all down the southern coast. there are a lot of aircraft in those trees. |
#2
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On May 5, 7:58 am, Stealth Pilot
wrote: The alternate wood I'm using has been australian queensland hoop pine. I found the batch I had a bit brash (a timber term meaning brittle short grained wood) so I was on the lookout for something a little safer for use in my Turbulent. well for the structural bits anyway. Australia's equivalent of Home Depot is Bunnings hardware. The stores are layed out as an exact clone of the american stores, but that is bye the bye. What I discovered in Bunnings one day was some extremely knotted planks of some yellowish wood. between the bazillion (a huge number) of knots was some amazingly fine grained timber. about 0ne ring per millimeter. the wood felt quite reasonable for weight so I bought a plank to experiment with. At this stage I had no idea what the wood species was. the stuff had a weedy smell when cut. it steamed easily and seemed to glue with epoxy really well. I used the straight grained pieces for the turtledeck bows of my first Turbulent fuselage. I experiemented some more with the remaining wood and couldnt fault it as a construction timber. I had a brainwave one day and hunted out the receipt off the floor of the car. alaskan yellow cedar was what the receipt called it. I had visions of weedy little trees in wind swept tundra being raped over by alaskan timber harvesters :-) I discussed the need to test the wood to determin its strength with an aero engineer friend. the next night he sent me the full design strength specs for the wood. having never heard of it before, this stunned me. I did some google searching and discovered some truely interesting facts regarding alaskan yellow cedar. the weedy smell only occurs when the wood has a high moisture content. when the wood is down at moisture contents suitable for aircraft use the wood is odourless. what a useful property an indicator of useful moisture content is. Trees have been discovered in forests that have no insect or microrganism attack even after standing as dead trunks for 150 years. It turns out that alaskan yellow cedar is rated as the softwood most inherently resistant to attack by bugs. another really useful property. I discovered an early aeroengineering text that gave comparitive rundowns of alternative woods to the ubiquitous Spruce. Alaskan yellow Cedar is rated as a highly shock absorbent/resistant wood sutiable for the most arduous structural use, which is the very opposite of brash timber. the thing that floored me though was the reason why spruce was selected as the wood of choice, it wasnt spruce's properties, it was just that there appeared to me more millable timber available. Alaskan yellow cedar, far from being a lower grade alternative wood to spruce, is actually a better timber in a number of it's properties. I was amazed. an alternative timber selected on a hunch turned out to be a winner. My second attempt D3 Turbulent is shaping up to be a pearler of an aircraft in Alaskan Yellow Cedar and Qld Hoop Pine marine ply. Dont knock some of those alternative timbers. Some mean that the drying up of spruce is an artifact of history, not the end of timber aircraft. ...which is good 'cause timber aircraft are wonderful building experiences. Stealth (not a single nail used in construction) Pilot btw my rape picture turned out to be a vivid imagination. there are huge stands of majestic alaskan yellow cedar all down the southern coast. there are a lot of aircraft in those trees. I grew up in the Canadian province of British Columbia, right next to Alaska. We used yellow cedar sometimes. Stuff stinks when you cut it. There are other BC woods that are useable in aircraft, too, like Engelmann Spruce (similar to Sitka Spruce but found in the drier areas), Ponderosa Pine (though BC's pines have been decimated in the recent Pine Beetle infestation) and Douglas Fir, which, while technically a softwood, is considerably harder and stronger and dimensions can be reduced 10% or so when using it in airplanes. Reducing any dimension can upset hundreds of other dimensions, so most people don't bother with it. It would still be heavier than Sitka anyhow, even at 10% smaller. And it splits/splinters easily. Western Red Cedar has been used in airplanes, too, but it's not so strong. When I was in South Africa last fall the local homebuilders there were using Eucalyptus, which they call Saligna once it's turned into lumber. South Africa has huge plantations of this stuff. In the US a few years ago I flew over big pine plantations in North Carolina. Trouble with those is the rapid growth and therefore low ring count per inch. The Americans also have Basswood and some different Cedars. Dan |
#3
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On May 5, 9:05*pm, wrote:
On May 5, 7:58 am, Stealth Pilot wrote: Dont knock some of those alternative timbers. Some mean that the drying up of spruce is an artifact of history, not the end of timber aircraft. If you follow the spruce specs back far enough, you eventually run into "Them Wright Boys", and beyond that, Octave Chanute. I think the reason they went with spruce back in the day was because it had the highest strength-to-weight properties and it was available in the local lumberyards in lengths exceeding 16 feet. Keeping in mind that both Chanute and the Wrights were using eastern species of spruce, what they referred to as "West Virginia Silver Spruce." Exactly which species that is, I dunno. But its what they could get, it was light, and it worked better than the alternatives like southern yellow pine. A quick look back at the Wrights' notebooks tells us that thier 1904 machine was originally pine, but had a nasty habbit of shattering parts when it crashed, uh, I mean landed. Broken parts were eventually replaced with spruce. Truth is that lots of things will work for building an airplane. Some better than others. By what degree is often the determining factor. But as resources deminish, alternatives look better. Harry |
#4
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wright1902glider wrote:
On May 5, 9:05 pm, wrote: On May 5, 7:58 am, Stealth Pilot wrote: Dont knock some of those alternative timbers. Some mean that the drying up of spruce is an artifact of history, not the end of timber aircraft. If you follow the spruce specs back far enough, you eventually run into "Them Wright Boys", and beyond that, Octave Chanute. I think the reason they went with spruce back in the day was because it had the highest strength-to-weight properties and it was available in the local lumberyards in lengths exceeding 16 feet. Keeping in mind that both Chanute and the Wrights were using eastern species of spruce, what they referred to as "West Virginia Silver Spruce." Exactly which species that is, I dunno. But its what they could get, it was light, and it worked better than the alternatives like southern yellow pine. A quick look back at the Wrights' notebooks tells us that thier 1904 machine was originally pine, but had a nasty habbit of shattering parts when it crashed, uh, I mean landed. Broken parts were eventually replaced with spruce. Truth is that lots of things will work for building an airplane. Some better than others. By what degree is often the determining factor. But as resources deminish, alternatives look better. Harry What was it you used on your Flyer, Harry? Richard -- (remove the X to email) Now just why the HELL do I have to press 1 for English? John Wayne |
#5
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On May 7, 12:21*pm, cavelamb himself wrote:
What was it you used on your Flyer, Harry? Richard I used sitka spruce for most of it because that's the closest that I could find to the Chanute specs and it was my best guess for an alternate. Keeping in mind of course that only about 1/2 of a Wright glider was spruce. The other 1/2 was white ash. Just about any part with a bend in it - ribs, landing skids, wingtip bows, canard leading & trailing edges, were either steam-bent ash, or were laminated from ash. By the way, steam-bending is 90 times harder than it looks and 127 times more time-consuming. Supposedly, Ken Hyde of "The Wright Experience" actually used West Virginia silver spruce for his machines. Theyway I heard it, and this is NOT a verified fact, he found someone with a tree, had it cut & milled, etc. His wood did look a little different from mine, but that have been from the finish his people used. "The Wright Experience" was funded by Ford (yeah, that Ford), several other major corps., and Harry Combs. SUPER DEEP pockets folks. They spent millions building what cost me a few thousand. Admittedly, I did have to interpret a few parts and materials for my machine just because the original materials weren't available for less than millions, or there simply wasn't any info. available for a particular part. But I can document my plane to 95% accuracy. Harry |
#6
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Try this, don't know if it's what your looking for or not.
http://www.fpl.fs.fed.us/documnts/fp...tr113/ch04.pdf Lou |
#7
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wright1902glider wrote:
Supposedly, Ken Hyde of "The Wright Experience" actually used West Virginia silver spruce for his machines. Theyway I heard it, and this is NOT a verified fact, he found someone with a tree, had it cut & milled, etc. His wood did look a little different from mine, but that have been from the finish his people used. "The Wright Experience" was funded by Ford (yeah, that Ford), several other major corps., and Harry Combs. SUPER DEEP pockets folks. They spent millions building what cost me a few thousand. They are building (built) everything from the kites to the 1911 model B and then actually fly them: http://ns97.webmasters.com/*wrightex...sion/index.htm |
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