Thanks John for the info. I have been side-tracked since this dicussion started and have not done much research. I find the topic interesting because while magnesium is strong and as you said and used more in the earlier days the topic got my curiosity up, because like you said, it corrodes and cracks so easily. While it is strong it doesn't have the flexibility that aluminum has. Anyway thanks much for the info and I do plan on taking some time and really researching the early uses of magnesium in aircraft production.
Charlie