14×14 {-1, +1} matrix of maximal determinant

Ratio of |Det R| to Ehlich/Wojtas bound: 1

M=R^TR=R R^T:

14  2  2  2  2  2  2  0  0  0  0  0  0  0
 2 14  2  2  2  2  2  0  0  0  0  0  0  0
 2  2 14  2  2  2  2  0  0  0  0  0  0  0
 2  2  2 14  2  2  2  0  0  0  0  0  0  0
 2  2  2  2 14  2  2  0  0  0  0  0  0  0
 2  2  2  2  2 14  2  0  0  0  0  0  0  0
 2  2  2  2  2  2 14  0  0  0  0  0  0  0
 0  0  0  0  0  0  0 14  2  2  2  2  2  2
 0  0  0  0  0  0  0  2 14  2  2  2  2  2
 0  0  0  0  0  0  0  2  2 14  2  2  2  2
 0  0  0  0  0  0  0  2  2  2 14  2  2  2
 0  0  0  0  0  0  0  2  2  2  2 14  2  2
 0  0  0  0  0  0  0  2  2  2  2  2 14  2
 0  0  0  0  0  0  0  2  2  2  2  2  2 14

R:

-++++++++-+---
+-+++++-++-+--
++-++++--++-+-
+++-+++---++-+
++++-+++---++-
+++++-+-+---++
++++++-+-+---+
-+++-+--++++++
--+++-++-+++++
+--+++-++-++++
-+--++++++-+++
+-+--++++++-++
++-+--++++++-+
+++-+--++++++-

Notes:

1. Reported to be maximal in [E1].
   
2. R is unique up to equivalence [C3].