Originally published June 1993
For those of you who have joined the chapter in the last eight months, I'm one of the original members of the chapter. The design group was my way of doing one of the things I enjoy most, talking about airplanes. I live in the Northwest now but am still a member of Chapter 1000.
This month I have a modest proposal for solving the problem of getting enough aircraft grade spruce for building our airplanes. Most of us are management or engineering/technical types so this particular approach may not have occurred to us. What I'm proposing is cloned wood. Actually, genetically engineered wood is probably a more accurate description, but cloned wood has such a nice ring to it. I propose not just improving the tree, but actually growing spruce in a tank. What would be ideal is growing the cells in a rectangular tank so that you end up with a spruce plank rather than a whole tree to be cut up.
There are some things that could be done to significantly improve the building quality of the wood that is grown this way. These things may not be possibly at the moment but could be in the not too distant future. One of the most significant things that could be done would be to get the cells to build up layer by layer from the bottom of the tank to the top. I don't know if it would be better to have the tank laying on its side or up on end for the growing process. If it was on its side it would add the additional problem of getting the wood to grow in a different orientation to gravity than it normally does. I don't know enough to say if this would be a significant problem. In either case, being able to get the cells to grow uniformly would eliminate growth rings and solve the problem of grain orientation and its effect on wood strength. A much more consistent and reliable building material would result. The other thing that would help would be to eliminate the pitch pockets and knots. By turning off the genetic coding that produces branches you eliminate another source of non-uniformity that reduces the strength of the final product.
If shrinkage of the wood could be accurately predicted it should even be possible to grow things like spars to final shape, or nearly so, needing only some final fine shaping to have a finished product. Of course there is the ultimate proposal, courtesy of our illustrious president, Bob Waldmiller, that you simply grow an entire airframe in one piece, that only needs to be dried, varnished and covered to create a complete airplane. This proposal may be somewhat tongue in cheek, but is not entirely out of the realm of possibility.
Contents of The Leading Edge and these web pages are the viewpoints of the authors. No claim is made and no liability is assumed, expressed or implied as to the technical accuracy or safety of the material presented. The viewpoints expressed are not necessarily those of Chapter 1000 or the Experimental Aircraft Association.
Revised -- 22 February 1997