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Long Coot August 2010


By petehdgs - Posted on 22 January 2011

Sunday, August 01, 2010

This morning I spent a fair amount of time looking at wood aircraft building information and articles.  I downloaded a copy of AC43-13-1B,  this is an FAA publication on standards and practices for building aircraft structures and systems, including wood, fabric, fiberglass, metal, control cables, hardware, and electrical.  I read some of it and an article Aircraft Wood, written Dec 88 that discuses the subject overview quite rapidly and in some detail.  I learned that Douglas Fir lumber can be substituted for Sitka Spruce in all applications.  DF is 26% heavier and 23% stronger than SS and more readily available.  I learned that aircraft wood is sold only partially graded, that the finished piece must be inspected by the installer to meet or exceed Mil-S6073.  Among the requirements are: 1) vertical grain running parallel to the piece and 2) a slope of 1/15 or better, a minimum of 6 grains per inch for SS and 8 grains per inch for DF.  I found Colonial Hardwoods in Springfield that specializes in hardwoods and could become a source, and I found McGee Lumber in Charlotte NC that specializes in high quality lumber, including close grained DF boards.  So I have decided that all the lumber on the Long Coot will be Douglas Fir. 

Yesterday I did some research into plywood, as part of my ongoing research into suitable plywood for use on the Long Coot.  I finally decided that I will be using 3mm Okoume plywood and I will be purchasing it from Harbor Sales in Baltimore, MD.  I had made this decision based in part on this plywood being manufactured to BS1088 standard, which I had deemed earlier to be acceptable for this project.  It wasn’t until this morning that I actually verified this to be true.  Aircraft plywood must meet or exceed Mil-S6070, a plywood standard that I found this morning and read.  I compared it to BS1088 that I found on Boatbuilding Central or Bateau.com, and BS1088 plywood meets or exceeds all sections of this standard. 

Saturday, August 14, 2010

Last weekend I received my new copy of The Gougeon Brothers on Boat Construction, Wood and West System Materials.  This edition was revised in 2005 and covers the most modern wood/epoxy building techniques.  I have been reading over it ever since I got it.  I also did some research online, and found a lot of useful information at Boatbuilder Central, Bateau.com, and http://bateau2.com/.  I have decided the best building method for the hull is the Self-Aligning Jig system as described in the tutorial at bateau2.com.  This system uses a strongback constructed of 2 2x12s put together like a ladder.  Gougeon Brothers also recommends stretching a 1/16 steel cable from the front to the back to use as a centerline reference for all measurements.  The strongback should be slightly longer then the boat itself, and the bulkheads or frames are mounted to it temporarily, in their correct relative positions.  Hull planking is then applied, fiberglassed on the outside, removed and fiberglassed on the inside.  A very interesting and efficient way of building a one-off boat structure.  

This week I also received EAA Wood Aircraft Building Techniques, an older collection of Sport Aviation articles that I feel covers the late 50s through the 70s.  There is a very interesting 2 part article on Geodetic Aircraft Structures that are made up of a crisscross of wood strips at right angles to each other.  While I am not interested in this building method, the crisscross web could be cut into sections of plywood to reduce weight without sacrificing basic strength.  There can be considerable weight savings depending on the type of crisscross chosen and its specific dimensions.  I think this has great potential for the top-sides, upper bottom and tail, but not the lower bottom of the hull which will be subjected to the hard pounding of the water.  I am considering this approach for much of the sides and top of the hull, and in part for some of the bulkheads.  Cutting the crisscross sections will be time consuming, but could easily cut the weight of the finished skin in half, making it worth the effort. 

I have been looking at the driveway and shop building that will be required to build the aircraft.  Bette has agreed to let me put up a temporary garage for this project.  There is a 13 x 20 steel framed tent-like structure available, so I’ll use that to start.  I also need room to put a dump trailer in the yard, and possibly a boat trailer, so I will extend the driveway behind where the service truck is parked.  This will require cutting 3 trees, and I’ll also cut 1 tree next to the garage site.  Once done, I’ll bring in gravel and timbers and make a level place for the garage and gravel the drive for the trailer.  I still need to finish cutting up the old camper and remove it. 

Wednesday, August 25, 2010

Today I worked some more on cutting up the old camper.  I had a problem with the saw that slowed me down some.  So during a break I reserved the FAA registration N number N225XC.  225 is the first three digits of my Spotsylvania VA Zip code, X for Experimental and C for Coot.  I also reserved 224XC for Fredericksburg EZF and 227 XC for Culpeper CJR.  I might not keep them, but what the hell.  I emailed the Richmond FSDO and requested form 8050-1 so that I can register the aircraft.  I have a tree man lined up for Saturday. 

Sunday, August 29, 2010

No tree man this weekend.  As it turns out, Bette is NOT in agreement about cutting trees to facilitate the building of a temporary garage.  But she says she is ok to cut trees for a permanent garage.  I have requested the services of Ron McCormick of Opportunity Homes, who lives just down the street.  I have asked him to survey the home and to quote a new garage, a new roof and a rework on the front stoop.  We’ll see where that takes us. 

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