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Engine basics => Engine set up tips => Topic started by: Matt Colan on September 10, 2009, 02:09:18 PM
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While we were at the Mass Cup, where it was a little on the windy side, we noticed something that I'll explain here. Grandpa said after his first official flight that his P-40 was flying a little fast so on his next flight he richened it up. The wind was blowing about 10mph on both flights. On the first flight, I saw him fly a couple VERY low bottoms, and he said the plane was flying too fast when it landed. He richened it up the next flight where the motor only broke at the very top of the wingover, everything else was a four-cycle. When he landed he said he had more control over the plane and said it was a great motor run. I kind of noticed the same thing from a practice flight, where I just brought the needle in a little, and there was a little windup. I did one loop with the motor screaming on my official flight and I had to hang on it to make it turn. We switched fuels and when the motor was running rich with about the same windspeed, there was no windup what so ever, and the plane stayed out there.
Now our logic now is if it is blowing about 10-15, leave the needle in the same area as if it were a calm day, or even richen it up a little more to prevent that windup. Does this make sense?
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When you are in the downwind direction, the airplane is getting energy out of the wind. The best brake you have is a slow moving prop, so I can easily believe what you say.
With electric power and running a constant rpm, one thing you notice is that you use less power from the battery on a windy day than a calm. The wind is helping you climb in the downwind maneuvers. In our case the constant rpm mode lets the motor act as a brake when the plane tries to speed up. y1