The "Flop" is a modified Orion with a 1" longer nose and a 2.5" shorter tail. The tail moment arm was measured from wing trailing edge former to elevator hinge line (a "mean" hinge line). The The RCM&E Taurus has 23.5" and MAN Taurus 24.5", which is even 3"/4" more than the MAN Orion and 5.5"/6.5" more than the "Flop". (The differences are slightly exaggerated by perspective, though.)

Maybe the tail moment arm from wing trailing edge to elevator hinge line at stabilizer root is even the same as on Orion. But the forward sweep makes for a shorter effective moment arm. On Orion, the vertical tail and rudder hinge line are raked and the moment arm is longer than that of the stab. On the "Flop", the rudder hinge line is vertical and has the same moment arm as the elevator at root.

A bit guesswork. Seems span of wing and stab are like on Orion, but both incidence angles are zero and the wing is thicker (17% ?) and has less dihedral. That would qualify the model as a Taurus. The Orion ailerons are still there as well as 12" root chord, but the tip chord is even longer than on Orion what is seen on no other model. Fuselage shape is not really modified, but the engine is inverted. Still the thrust line is not that high, seems it's 2" from top, only 0.5" higher than on Taurus. (Vertical dimensions are arguable.)

Obviously, main problems were moment arms and empennage shape. Intermediate step between Orion and "true" Taurus, bashfully called "a modified version" of the Taurus, "strictly experimental", in contrast to the "final Taurus".