Some of the shortest 2 edge flips (28*):
U R U R U2' R U' R2' U' R' U2 R U2' R U2' R U R' U2 R2 U R2' U' R' U2 R2' U2 R2'
U R U R U2' R2 U2' R2 U' R' U2' R U2 R2 U' R U R2' U R2' U R2 U' R' U2' R' U R2'
U R U R2' U R' U2' R' U' R2 U R2' U R2' U R U' R2 U2 R U2' R' U' R2 U2' R2 U2' R
U R U R2' U2 R2' U2 R' U' R2' U R2 U2 R' U R U2' R U2' R U2 R' U' R2' U' R U2' R
U R U2 R U' R2 U' R' U' R' U2 R2' U2 R2' U R U2 R' U2' R2' U R' U' R2 U' R2 U' R2'
U R U2 R' U2' R2' U R' U' R2 U' R2 U' R2' U R U2 R U' R2 U' R' U' R' U2 R2' U2 R2'
U R U2' R U2' R U2 R' U' R2' U' R U2' R U R U R2' U2 R2' U2 R' U' R2' U R2 U2 R'
U R U2' R U' R2' U' R' U2 R U2' R U2' R U R' U2 R2 U R2' U' R' U2 R2' U2 R2' U R
U R U2' R2 U2' R2 U' R' U2' R U2 R2 U' R U R2' U R2' U R2 U' R' U2' R' U R2' U R
U R U2' R2 U2' R2 U' R' U' R' U2 R' U R2 U R U2' R' U2 R' U2 R' U' R U2' R2' U' R2
U R U2' R' U2 R' U2 R' U' R U2' R2' U' R2 U R U2' R2 U2' R2 U' R' U' R' U2 R' U R2
U R U' R2 U2 R U2' R' U' R2 U2' R2 U2' R U R U R2' U R' U2' R' U' R2 U R2' U R2'