Gregg Brightwell
Well Known Member
Good title for the thread, but sorry, nothing fancy. On the -4, there have been several instances where lightening holes are 'optional'. I dare say, that anyone wanting to build a light airplane that declines this option, also pees into the wind 
Just for kicks today, I measured the weight of my lightening hole cutouts from ONE flap brace. 3.7 oz! (On a HIGHLY accurate set of scales, that measure down to the grain - thanks Kurt)
For sport, I weighed the W-421 Flap brace before doing anything to it - even still had the blue plastic on, but that is small potatoes. The flap brace as is, weighed 15.4 oz. The 'completed' flap brace, with lightening holes cutout and plastic peeled, weight 9.8 oz! That is better than a 5 oz. gain! Do the math, and the two flap spars, and braces, is about a pound and a quarter saved! Just thought this was neat. Certainly not ground breaking, but good data.
Just for kicks today, I measured the weight of my lightening hole cutouts from ONE flap brace. 3.7 oz! (On a HIGHLY accurate set of scales, that measure down to the grain - thanks Kurt)
For sport, I weighed the W-421 Flap brace before doing anything to it - even still had the blue plastic on, but that is small potatoes. The flap brace as is, weighed 15.4 oz. The 'completed' flap brace, with lightening holes cutout and plastic peeled, weight 9.8 oz! That is better than a 5 oz. gain! Do the math, and the two flap spars, and braces, is about a pound and a quarter saved! Just thought this was neat. Certainly not ground breaking, but good data.
