My OperaAll tied up
Tuesday, October 12, 2010 2:28:14 PM
In doing research for the glider part of the job was to find what kind of wood was used by the Wright brothers. Ash was used for the main purpose of bending; Ash when prepared the right way a person can tie a knot in the wood. I tried it and it worked, I wish I had kept it to show you, but my 11 year old granddaughter took a liking to it and grandpa being big old softy……. Well you know who got the knot. Ash is a medium weight but tough as nails a great wood to use.
Now we come to Spruce, not any old Spruce but it has to be Sitka Spruce, of aircraft quality, why you may ask? Sitka is very light weight, but extremely strong. The aircraft quality of Sitka Spruce must have straight and level grain. In fact the grain over the length of the board can be no more than 5% slope, and free of any defects like knots, or wavy grain. After all some pilot’s life may depend on it.
The de Havilland DH 98 Mosquito twin engine bomber of WWII fame, was made of mostly Sitka Spruce and plywood and at the time was the world’s fastest production aircraft. That’s why I used Sitka Spruce not because of the speed but because to quote a USA TV commercial for watches “it takes a licking and keep on ticking.”
Not have worked with Sitka Spruce before, I purchased one board, 9in.wide 2in. thick and 9ft long, I found I could lift it with one hand, it was that light. On the table saw I cut the required size with no effort. When held at the end the ½ in. by ¾ by 9 ft. did not bend or wobble but was straight as an arrow. I was impressed with this wood. The spars of a wing are the long pieces running the length of the leading and tailing edge of the wing, usually one or two pieces glued, bolted together to form a one solid piece. (See photo) that shows the leading and tailing spars clamped to the wing tips made of bent Ash. On the leading spar I rounded the edges on the leading side with a router. This is done for aerodynamic reasons.
Attaching the wing ribs to the leading and tailing spars to form the wing was done by tying the ribs to the spars. YES! You heard me right, tying the ribs to the spars. Remember in 1902 the glue they had was crap, the Wrights didn’t want to nail or screw the ribs to the spars, they also didn’t want holes in the spar to weaken it, so the Wright’s tied the ribs. Marlinship is a crusty old word that is little used today, but it was a skill that almost every Victorian boy learned when he was old enough to tie his shoelaces. The last vestige of marlinship that survived the turn of the twenty-first century is the knot-tying section of the Boy Scout Handbook. Marlinship was a crucial skill for a handyman when the Wright brothers were building gliders, and waxed lined cord was the Victorian equivalent of duct tape. By using this material to hold the airframe together, the Wrights made it able to withstand hard landings - each joint would give slightly when stressed then return to its original position. And if a part did break, it was easy to repair. Just cut the old lashes and lash in a new part.
The Wrights used two knots over and over in making building the glider frame. The ribs are attached to the spars with saddle lashes. Almost all the remaining parts, including most of the hardware, are attached with whiplashes. The waxed linen cord, I quickly found out, is magic stuff for lashing. Because the cord is waxed, it sticks to itself or the wood while you tie off the knot. As a result, it’s much easier to make a tight lash - you don’t have to hold the tension of the cord while you tie the knot. See the attached photos of the wing construction.
Now we come to Spruce, not any old Spruce but it has to be Sitka Spruce, of aircraft quality, why you may ask? Sitka is very light weight, but extremely strong. The aircraft quality of Sitka Spruce must have straight and level grain. In fact the grain over the length of the board can be no more than 5% slope, and free of any defects like knots, or wavy grain. After all some pilot’s life may depend on it.
The de Havilland DH 98 Mosquito twin engine bomber of WWII fame, was made of mostly Sitka Spruce and plywood and at the time was the world’s fastest production aircraft. That’s why I used Sitka Spruce not because of the speed but because to quote a USA TV commercial for watches “it takes a licking and keep on ticking.”
Not have worked with Sitka Spruce before, I purchased one board, 9in.wide 2in. thick and 9ft long, I found I could lift it with one hand, it was that light. On the table saw I cut the required size with no effort. When held at the end the ½ in. by ¾ by 9 ft. did not bend or wobble but was straight as an arrow. I was impressed with this wood. The spars of a wing are the long pieces running the length of the leading and tailing edge of the wing, usually one or two pieces glued, bolted together to form a one solid piece. (See photo) that shows the leading and tailing spars clamped to the wing tips made of bent Ash. On the leading spar I rounded the edges on the leading side with a router. This is done for aerodynamic reasons.
Attaching the wing ribs to the leading and tailing spars to form the wing was done by tying the ribs to the spars. YES! You heard me right, tying the ribs to the spars. Remember in 1902 the glue they had was crap, the Wrights didn’t want to nail or screw the ribs to the spars, they also didn’t want holes in the spar to weaken it, so the Wright’s tied the ribs. Marlinship is a crusty old word that is little used today, but it was a skill that almost every Victorian boy learned when he was old enough to tie his shoelaces. The last vestige of marlinship that survived the turn of the twenty-first century is the knot-tying section of the Boy Scout Handbook. Marlinship was a crucial skill for a handyman when the Wright brothers were building gliders, and waxed lined cord was the Victorian equivalent of duct tape. By using this material to hold the airframe together, the Wrights made it able to withstand hard landings - each joint would give slightly when stressed then return to its original position. And if a part did break, it was easy to repair. Just cut the old lashes and lash in a new part.
The Wrights used two knots over and over in making building the glider frame. The ribs are attached to the spars with saddle lashes. Almost all the remaining parts, including most of the hardware, are attached with whiplashes. The waxed linen cord, I quickly found out, is magic stuff for lashing. Because the cord is waxed, it sticks to itself or the wood while you tie off the knot. As a result, it’s much easier to make a tight lash - you don’t have to hold the tension of the cord while you tie the knot. See the attached photos of the wing construction.
