You can find an old short interview with Guy about making propellers here. The person doing the interview is clearly trying to avoid technical material and asks very naïve questions, but it gives a bit of insight into manufacturing at the Ole Fahlin Memorial Propeller Shop. Commercial and high production propellers are made with numerically controlled machines and duplicating machines. But at the propeller shop, they are essentially hand-made one at a time using such basic machines as a drill press, bandsaw, belt and orbital sanders, and various hand tools, and when I first encountered the process, a frightening cutting tool driven by a flexible shaft. It was the process of making these highly precise and sophisticated devices from wood by hand that particularly caught my attention.
Another thing I found attractive was the quality of the wood needed to make propellers— straight grain, no knots, no flaws. A far cry from what one can get at Home Depot, or even at a major lumber yard. It seemed an honor to be able to work with such material.
In order to learn more about the process of making propellers, I commissioned Guy to make me one, and requested that he work on it only while I was present so I could watch. Step one was to find the wood and a glue a number of boards together under very high pressure. Step two, as the video shows, was to drill a hole in the middle. So far, so good. He then drew a profile of the propeller on the blank with a template and used the band saw to cut close to the line—still fairly straight forward. Then, to my amazement, Guy drew some rudimentary lines on the sides of the blank, and proceeded to push it through the band saw time and time again, until he had a rough propeller form that was within ¼ of an inch or so of the final shape. I had never seen a band saw used in this way—as a large carving tool—and it was clear that not only had he done this many, many times, but he had a very clear three dimensional vision of what the propeller would look like. He reminded me of the teacher of a sculpture course I once took. When he worked by removing material, say from a stone or block of wood, he would begin by removing very large chunks. When I once asked him whether he wasn’t afraid he would take too much off with these initial chunks, he replied “Oh no. My sculpture is in there and I know exactly where it is”.
Guy then used a large protractor device and a number of cross section templates at various stations along the propeller to reduce it to the final shape using the previously mentioned frightening cutting tool and the sanders. The process was both fast and slow—fast because of his skill, but slow because cutting too much means throwing away the valuable blank and the time spent. And the shape must be extremely accurate, not only for aerodynamic reasons, but also because the propeller must be perfectly balanced. In fact he did the final balancing with the varnish that was applied to the finished wooden form along with the metal leading edge protection.
The result was beautiful, but since I did not have an airplane to put it on, and since it was only six feet long, I took it home and hung it on the wall of my home office, where it still resides, as can be seen in the following photo.
But I was hooked. I needed to make a propeller myself. Looking through the many plans and templates in the shop, I found an eight foot propeller with a very interesting curve used on the Spad, a well known World War I fighter. Guy agreed this was an excellent one for me to make, and so he found me the wood, we glued it together, and away we went. I say we, because I had not spent years doing this, and was afraid that I would screw up this wonderful piece of wood. So Guy hung over my shoulder and told me what to do and encouraged me until it reached close to the final form. He then added a bit of skillful work with a balance stand and a thick coat of varnish and pronounced it beautiful, a finding that I agreed with 100%. It is now inside the entrance hall to my house over the front door—see photo below.
Being now fully challenged I requested that I be allowed to make another one. This time I chose an 10 foot one that fit a 400 horsepower Liberty engine—also World War I vintage, and built in large numbers. I did not have a Liberty engine, but I seemed to have managed to use my first two propellers to advantage to add beauty to my house, and I had my eye on a bare 10 foot stretch of wall in the upstairs hall over a couple of doors.
This time, Guy stood further away from me, and even pretended that I was working on my own, even though I knew he was watching me like a hawk. But everything went well, and I finished it in only about ten times the number of hours he would have required—see the photo.
What next. Guy told me that at one time sixteen foot diameter four bladed propellers had been used on dirigibles and he thought he could get the plan for them. But I think he was kidding me, and I had to admit that I would never have a dirigible and that a propeller that size could not fit in my house unless I removed the roof. And also I realized I was up against one of my old problems, one that had arisen when I got on a run of making ship models (see terrible photo below—I didn’t want to take the glass off of the case) and found that this interest was eating up a frightening amount of my time. After deep thinking and some valuable input from my wife Marian (what—are you crazy?), I decided to continue my career at Stanford rather than trying to qualify as Guy’s assistant.