Spar material
07-26-2004 | 03:10 PM
#2
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From: Stansbury Park,
UT
RE: Spar material
Dave,
I've gotten my from the local hobby shop. Unfortunately, it came in sheets that needed to be glued together and cut into the spar material.....not sure if anybody sells it basically ready to go...
GS
I've gotten my from the local hobby shop. Unfortunately, it came in sheets that needed to be glued together and cut into the spar material.....not sure if anybody sells it basically ready to go...
GS
07-26-2004 | 03:21 PM
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From: Monroe,
NC
RE: Spar material
Dave,
Your local hobby shop.
You don't want to buy the sheets of endgrain balsa (like CST sells) for the spar. It is oriented for compression in the wrong direction (across the thickness).
I've disected a LOT of wings and what almost everybody uses is 1/4" or thicker sheets of balsa that are cut and glued. Some use Rohacell in the outer part tip part of the spar to save weight. The compression load is the highest from the top surface to the bottom surface, and that is the direction the grain is usually oriented in. If you need 4 spars, just cut 4.5" or so sections of 4" to 6" wide balsa and glue them together edge to edge. Then cut the spars.
Some builders do use laminated spars so that they get compression strength both vertically and along the length of the spar. There are usually 3 layers with the outsides being vertically oriented. The layers are typically 3/32" to 1/8".
Some builders cap the spar with CF unidirectional laminate before it in installed into the wing. Some put the CF laminate in the skins, and some do both.
Your local hobby shop.
You don't want to buy the sheets of endgrain balsa (like CST sells) for the spar. It is oriented for compression in the wrong direction (across the thickness).
I've disected a LOT of wings and what almost everybody uses is 1/4" or thicker sheets of balsa that are cut and glued. Some use Rohacell in the outer part tip part of the spar to save weight. The compression load is the highest from the top surface to the bottom surface, and that is the direction the grain is usually oriented in. If you need 4 spars, just cut 4.5" or so sections of 4" to 6" wide balsa and glue them together edge to edge. Then cut the spars.
Some builders do use laminated spars so that they get compression strength both vertically and along the length of the spar. There are usually 3 layers with the outsides being vertically oriented. The layers are typically 3/32" to 1/8".
Some builders cap the spar with CF unidirectional laminate before it in installed into the wing. Some put the CF laminate in the skins, and some do both.
07-26-2004 | 03:22 PM
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From: Waseca,
MN
RE: Spar material
I've gotten it from several sources that most people are just gluing sheets together, and then buzzing them through the table saw.
I guess I'm a little lazier than that, and hoping to find a source....
I guess I'm a little lazier than that, and hoping to find a source....
07-26-2004 | 03:38 PM
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From: Stansbury Park,
UT
RE: Spar material
One nice thing about doing it yourself is that you can customize the wood used. You can use harder, stronger pieces at the center section, and lighter ones near the tips, and save weight.
GS
GS
07-27-2004 | 01:17 PM
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RE: Spar material
Dave,
Go get some 6" wide sheets of 1/4" balsa and glue them together. Bag glass on them if you want, then saw into spar material. You might find that one of the balsa suppliers will set you up with 12" sheets, or may even custom make the sheets for you. But, if it is in low volume, the cost may not be prohibitive.
Michael
Go get some 6" wide sheets of 1/4" balsa and glue them together. Bag glass on them if you want, then saw into spar material. You might find that one of the balsa suppliers will set you up with 12" sheets, or may even custom make the sheets for you. But, if it is in low volume, the cost may not be prohibitive.
Michael
