There is an art book
Italian Art, 1250-1550: The Relation of Renaissance Art to Life ... (1987) by Bruce Cole, saying "...
sword which Pippo seems to flex with his bare hands ...". If we examine this fresco a bit closer, we could see that Pippo actually grips the hilt with his right hand and just barely touches the blade with his left hand (potentially the sharpest part of the blade): it seems that just his thumb and index finger are holding the blade, other fingers simply touch the flat.
An Italian source - a blog on interesting things in Florence (
http://curiositasufirenze.wordpress.com/?s=Pippo) has an interesting entry about Pippo with at least one historical detail explained correctly (Hispanus vs ispán). Some explanation on the sword:
"
In questo dipinto Pippo Spano è raffigurato con un’ arma in pugno: un osservatore scrupoloso può notare che non si tratta di una comune spada, bensì di una sciabola come quelle in uso all’ epoca presso le milizie dell’ Ungheria."
It is difficult to prove that the sword in Pippo's hand definitely a sabre, but there are several things that support this assumption: the way of holding the sword, the asymmetrical pommel (!), his prolonged contact with Turks. The Hungarian National Museum stores the so-called Szikszó sabre, IIRC the blade has a central fuller and two edges. I will check it later.
BTW the earliest depiction of a hussar can be found on the scabbard of Szikszó sabre (between 1490-1510).