KR> Mil-spec 6073 vs. any other wood
I am involved in building a homemade lumber drying kiln right now and have been studying what I can find on the 'net about it. It seems that the strength of the wood depends on the drying process as well as the species. Non-mil-spec lumber might not have been dried using the process that gives the most strength. Check that out. The drying process is quite complicated.
KR> Mil-spec 6073 vs. any other wood
"I've been reading articles about selecting and testing wood. Lots of good info. Besides Sitka Spruce, Port Orford Cedar, Alaskan Yellow Cedar and Hemlock are rated as good choices for airplanes." I am using Douglas Fir for the longerons and spars on my KR2SS, with one piece wing. The Fir is about 16% heaver but 15% stronger in tension and compression the spruce. I used to grade lumber many, many years ago. So I looked up the specs and inspect the lumber myself. Aircraft grade Douglas Fir is not cheap (look at lumber intended for boat masts and cabinet supplies). It is, however a LOT cheaper than aircraft grade Spruce! Pictures of the project are at http://picasaweb.google.com/103552664644911775549/KR2SS# . In picture 17 you will see the laminations of Fir for the longerons. Look carefully at the grain. Grain that fine is not cheap! BTW, it rook an extra 10 hours to build the forms so I could build the sides with the "bends" already in them. I thought that was faster than repairing broken longerons while trying to bend the sides into "submission". A large consideration was in making the inside seating area 42+ inches wide at the shoulders. That is a lot of bending of the sides if you build them flat! Bob Johnson Willamina, OR 97396 971-645-9491
KR> Mil-spec 6073 vs. any other wood
Thanks for the feedback, guys. One person mentioned mil spec 6073 describes how a tree must be gently handled, using a crane to lower it to the ground. I'd heard something like that before, but can't find any literature on this. I went through 5 pages of google searching for 'mil spec 6073' and came up only with a document from 1950. I couldn't find any reference to any required method of harvesting. It says that every 'piece' will be examined (visually) and one in twenty will be randomly sampled to be tested for specific gravity, moisture content, and brashness (brittleness). In other words, all of the 6073 wood gets looked at, but 95% doesn't get tested. And the brashness test is for only 4 ten inch long randomly selected pieces of the randomly selected 1 in 20 pieces, not along the whole length of board. Ron Alexander mentions this sampling in a series of articles on wood in Sport Aviation starting in December 1998 and the following 4 months. Dan
KR> Mil-spec 6073 vs. any other wood
Too heavy. Strength and weight need to be balanced, Virg On 12/24/2010 8:17 AM, Jose Fuentes wrote: > I wonder how good ole Southern Red Oak stand up to this list? Though I know > it's not the lightest. > > Joe >
KR> Mil-spec 6073 vs. any other wood
This is an EXPERIMENTAL aircraft. Try Marine Spar grade wood, Virg On 12/24/2010 12:02 AM, Dan Morehouse wrote: > I've been reading articles about selecting and testing wood. Lots of good > info. > > > I'm all for saving money and it would be neat to build with POC, if it's > really > top of the line. But I'm concerned that I may not be able to guarantee, even > by > inspection and testing, that this uncertified wood is as good or better than > > Thanks, > Dan > ___ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html >
KR> Mil-spec 6073 vs. any other wood
I wonder how good ole Southern Red Oak stand up to this list? Though I know it's not the lightest. Joe On Fri, Dec 24, 2010 at 3:50 AM, Gary Robison <djgaryl...@verizon.net>wrote: > I'll be interested to know > > GR > > > - Original Message - > From: "Dan Morehouse" <messyd...@yahoo.com> > To: <kr...@mylist.net> > Sent: Friday, December 24, 2010 12:02 AM > Subject: KR> Mil-spec 6073 vs. any other wood > > > > I've been reading articles about selecting and testing wood. Lots of good > > info. > > Besides Sitka Spruce, Port Orford Cedar, Alaskan Yellow Cedar and Hemlock > > are > > rated as good choices for airplanes. In fact, Eugene Parker wrote an > > article for > > EAA in 1984(?) in which he ranked Sitka Spruce 3rd in his list of best > > wood for > > airplanes, POC was number one, AYC was two. Googling POC comes up with > > BearCreekLumber.com. They're a half day's drive from me and quoted Sitka > > Spruce > > to be 25% more expensive than any of the other three. But this isn't > > mil-spec > > lumber. As I understand it, they can get very nice wood, but it would be > > up to > > me to inspect and test it. I read on this board how Harold Woods > suggests > > going > > about testing each piece by getting them a bit overwidth, ripping a piece > > the > > full length of the board on both edges, and testing those pieces. Sounds > > straight forward, but does that mean it's as good as mil spec 6073? > > > > So if I buy from ACS or Wicks, I'll get mil spec 6073, which means that > > some > > knowledgeable person thought this wood would be okay in an airplane. And > > if I > > buy this mil spec wood, do I still need to go through all the elaborate > > testing? > > If so, I'd end up with skinnier than called for wood, assuming they sell > > it in > > the exact width called for. > > > > I'm all for saving money and it would be neat to build with POC, if it's > > really > > top of the line. But I'm concerned that I may not be able to guarantee, > > even by > > inspection and testing, that this uncertified wood is as good or better > > than > > what a professional inspector has already deemed mil spec 6073 worthy. > > I've > > never inspected wood in this manner and don't know how reliable my tests > > would > > be. If buying certified wood removes all doubt about it's quality, the > > several > > hundred dollars extra I'd pay for this may be worth it. > > > > How did you guys go about buying, inspecting, and testing your wood? > > > > Thanks, > > Dan > > ___ > > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > > please see other KRnet info at http://www.krnet.org/info.html > > > > > > - > > No virus found in this message. > > Checked by AVG - www.avg.com > > Version: 10.0.1170 / Virus Database: 1435/3334 - Release Date: 12/23/10 > > > > > ___ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > -- Jose Fuentes Founding Father (one of and former Vice Prez) of Capital City.NET User's Group Former Microsoft MVP http://blogs.aspadvice.com/jfuentes
KR> Mil-spec 6073 vs. any other wood
I'll be interested to know GR - Original Message - From: "Dan Morehouse" <messyd...@yahoo.com> To: <kr...@mylist.net> Sent: Friday, December 24, 2010 12:02 AM Subject: KR> Mil-spec 6073 vs. any other wood > I've been reading articles about selecting and testing wood. Lots of good > info. > Besides Sitka Spruce, Port Orford Cedar, Alaskan Yellow Cedar and Hemlock > are > rated as good choices for airplanes. In fact, Eugene Parker wrote an > article for > EAA in 1984(?) in which he ranked Sitka Spruce 3rd in his list of best > wood for > airplanes, POC was number one, AYC was two. Googling POC comes up with > BearCreekLumber.com. They're a half day's drive from me and quoted Sitka > Spruce > to be 25% more expensive than any of the other three. But this isn't > mil-spec > lumber. As I understand it, they can get very nice wood, but it would be > up to > me to inspect and test it. I read on this board how Harold Woods suggests > going > about testing each piece by getting them a bit overwidth, ripping a piece > the > full length of the board on both edges, and testing those pieces. Sounds > straight forward, but does that mean it's as good as mil spec 6073? > > So if I buy from ACS or Wicks, I'll get mil spec 6073, which means that > some > knowledgeable person thought this wood would be okay in an airplane. And > if I > buy this mil spec wood, do I still need to go through all the elaborate > testing? > If so, I'd end up with skinnier than called for wood, assuming they sell > it in > the exact width called for. > > I'm all for saving money and it would be neat to build with POC, if it's > really > top of the line. But I'm concerned that I may not be able to guarantee, > even by > inspection and testing, that this uncertified wood is as good or better > than > what a professional inspector has already deemed mil spec 6073 worthy. > I've > never inspected wood in this manner and don't know how reliable my tests > would > be. If buying certified wood removes all doubt about it's quality, the > several > hundred dollars extra I'd pay for this may be worth it. > > How did you guys go about buying, inspecting, and testing your wood? > > Thanks, > Dan > ___ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1170 / Virus Database: 1435/3334 - Release Date: 12/23/10 >
KR> Mil-spec 6073 vs. any other wood
I've been reading articles about selecting and testing wood. Lots of good info. Besides Sitka Spruce, Port Orford Cedar, Alaskan Yellow Cedar and Hemlock are rated as good choices for airplanes. In fact, Eugene Parker wrote an article for EAA in 1984(?) in which he ranked Sitka Spruce 3rd in his list of best wood for airplanes, POC was number one, AYC was two. Googling POC comes up with BearCreekLumber.com. They're a half day's drive from me and quoted Sitka Spruce to be 25% more expensive than any of the other three. But this isn't mil-spec lumber. As I understand it, they can get very nice wood, but it would be up to me to inspect and test it. I read on this board how Harold Woods suggests going about testing each piece by getting them a bit overwidth, ripping a piece the full length of the board on both edges, and testing those pieces. Sounds straight forward, but does that mean it's as good as mil spec 6073? So if I buy from ACS or Wicks, I'll get mil spec 6073, which means that some knowledgeable person thought this wood would be okay in an airplane. And if I buy this mil spec wood, do I still need to go through all the elaborate testing? If so, I'd end up with skinnier than called for wood, assuming they sell it in the exact width called for. I'm all for saving money and it would be neat to build with POC, if it's really top of the line. But I'm concerned that I may not be able to guarantee, even by inspection and testing, that this uncertified wood is as good or better than what a professional inspector has already deemed mil spec 6073 worthy. I've never inspected wood in this manner and don't know how reliable my tests would be. If buying certified wood removes all doubt about it's quality, the several hundred dollars extra I'd pay for this may be worth it. How did you guys go about buying, inspecting, and testing your wood? Thanks, Dan
