What does a 15:1 grain slope indicate?

A 15:1 grain slope indicates that the grain of the wood deviates 1 inch over a distance of 15 inches. This measurement helps to assess the quality and straightness of the grain, which is crucial in aviation applications where structural integrity is paramount. A lower ratio, such as 15:1, signifies relatively straight grain, which is preferred for strength and stability. When the grain runs straight and true, it enhances the material’s performance under stress, making it more reliable for the demanding conditions in aviation.

In contrast, a grain slope represented by other ratios indicates different levels of deviation that can negatively affect the wood's performance. For instance, a 1 inch in 10 inches slope or the options mentioning 20 inches would suggest more significant deviations, which could compromise the structural integrity and overall quality of the wood.