Larry Cailliau’s 2006 World Championship Salt Mine F1D
My first trip to the Salt Mine was a real learning experience. The challenges the salt mine offers are much different from what we in the US are accustomed to. The first would be the cold and very humid conditions. The second would be trying to get the model to climb over 200ft. The third would be trying to fly in the dark.
After returning home I set out to develop a model that would be competitive in lower ceilings yet capable of conquering the salt mine. My old braced wings gave out to the newer unbraced wings because the braced wings wanted to fly straight under max torque. Many competitors had problems with their models stalling out at about 60-80ft. I contributed this to the models being vectored almost straight up at a high speed and very high torque. When the power burst diminished, the motor stick would straighten out causing more negative incidence in the stab causing the model to eventually stall. Because of this, I made stiffer motor sticks. The humidity made my stabs floppy and again under high speed a floppy stab is detrimental to stability. I changed my stab plan form to a more elliptical shape, thinking it would have fewer tendencies to twist. I also increased the root of the spar from .045” to .050”. These were my major design changes.
The summer of 2006 was spent trimming five models for the salt mines. I remember Jim Richmond telling me that I needed to climb about 75ft. on a quarter motor, which would be equivalent to salt mine conditions. At Champaign, I tried for two days experimenting with different props and trim setups. However, I was unable to achieve this. I again consulted Jim and he told me that a 19” 29p prop would get me up. When the all-time world’s best speaks, I listen!
When Johnson City came, I was equipped with my new props and had spent three days of quarter motor testing. Sure enough, all five planes climbed to 75ft. Minor trim changes were made. I found that my models flew best for ultra-high ceilings with 0 stab incidence and about 1/8” positive incidence in the wing. This was opposite to my low ceiling setup.
Day 1 in the salt mine was very disappointing. It was testing day and I could not get my quarter motors high enough. I was only getting about 7 1/2 minutes. After working all day it was time to quit. I was tired and disgusted. In the middle of the night it came to me, that I was using sport rubber ¼ motors which I made for initial testing because it was hard to break. The guys laughed, and eventually I myself thought this was kind of comical. The following morning I was eager to get some 5/99 on the model to see if this was truly the problem. Alas, things were looking up, proper altitude and 9 minutes plus.
Round one of the competition came and no one wanted to fly first. I volunteered. The flight could not have gone better, cruising just below the ceiling and staying centered the whole flight, touching down at 35:14. Little did we know that this would hold up to be the contests best flight!
Round two appeared to be going good with the model centered at the ceiling again. But Oh no, it started drifting to the side and was following the same pattern as John Kagan’s previous flight over the catwalks. Team manager, Ray Harlan, suggested that I attempt to steer it. It was a risky but necessary situation. The model was barely visible but somehow it flew onto the line. I was able to guide it back to the center. Getting it off of the line was even a bigger problem because the balloon was hiding the light on the airplane. It was just too dark. I made a guess at what angle to pull the line from the model and quickly moved away while asking everyone if it was off of the line. What luck! With the model now centered perfectly, the flight continued undaunted, and landed at 35:08, good enough for the win.
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