Brace and ledge frame

[rugbyfan2013]

Is there a formula for the dimensions of a brace and ledge frame?

Do you simple have a top rail and bottom rail, and then fit the middle rail halfway between the two?

Or is there a funny formula to make the proportions look better on the eye?

 

[Burnerman]

What do you have in mind?
For maximum strength, then a brace halfway....for minimum distortion, add diagonals (rising from the hinge, if there's going to be any).
John

 

[Dave54]

By "funny formula" I expect you're referring to the "golden rectangle" which has sides of about 1:1.6 in ratio. (Plenty about the maffs behind it on Wikipedia) It works well for making rectangular things, but would probably not look right being used to place the middle rail on a ledge and brace door which has different overall proportions.

Stick the middle one in the middle. That's what I'd do anyway!