Tony Bingelis vs. the Rest of the World (Bend Radius)

[rwanttaja]

Hmmmm.

According to just about every source I can find online, when one bends 4130N sheet steel, the bend radius should be at least three times the thickness of the metal (3T).

http://www.bjg-design.com/designbook/shbend.htm

However, on Tony Bingelis "Sportplane Construction Techniques," he specifies a 1T bend radius for "Aircraft steel".

Fly Babies use a bent 0.093" 4130 fitting to hold the landing gear on. Bowers doesn't specify a minimum radius, other than saying a "slight radius" in his generic instructions up front. Most Fly Babies I've seen seem to go for the 1T radius on this piece. Pete's cross-sectional diagram showing this piece also seems to show a tight radius.

So...3T or 1T? Anyone else want to throw an oar in?

Ron Wanttaja