Art built that mower to be able to claim "Worlds Fastest Lawnmower". That
awesome fat burners for men article and the turbine powered mower actually could mow grass.
In the late 1990's, I had a mowing business also. I had a XW2500 (25hp 60"cut) and a XXW4000 Suburban Turbine (Twin 25hp 72"cut). I turned the governors up to 3800 rpm on those Kohler engines. And when I went to look at a larger job. I was comfortable guestamating a 15 acre per hour rate for mowing.
Art designed a Tagdeck system to go behind his mowers. He would bring the mowers to Mentone and he told to break it. If ya break it, I know what is the weak link and where to reengineer it. A 50hp Diesel 72" cut and tagdeck, and we mowed the Mentone property in about 4 1/2 hours, and was just playing around.