For what it is worth the following is from my old (1960's) AIRCRAFT MECHANICS POCKET MANUAL by Joseph A. Ashkouti.
On page 5--19,a chart listing Typical Mechanical Properties of Wrought Aluminum Alloys shows the following: 6061-T4 at 35,000 Lb./Sq. in. Tensile Strength. (This is a Solution Heat Treated alumunum) And 6061-T6 at 45,000 Lb./Sq. in. Tensil Strength. (This is a Solution Heat Treated and Artificially Aged aluminum.) The 6061-T5 in question is an Artificially Aged ONLY aluminum, and per page 5--24, is a heat treat of extrusions produced only by the manufacturer (Alcoa). Bottom line, still do not know what the 6061-T5 has for Tensil Strength but I would estimate it is less than the 6061-T6. If the anticipated use is for primary structure or for flight controls you may want to consider increasing the part thickness to compensate for the reduced strength. Bob Morrissey recent buyer of a KR2S boat with some other "stuff "cam...@earthlink.net
