He rode his prolific galloper in track work himself up until well past his 80th birthday.
Charlie bred Walk Cool from a mare he owned Coolmoss and he was by King Of The Walk, who was a local stallion owned by Jack Murray from Eidsvold.
It took Walk Cool 133 starts to earn those 51 victories.
He placed 46 times as well.
In the saddle on 83 occasions of the 133 was former jockey Peter Rewald.
According to Peter, Sinclair and Walk Cool were recognised wherever they travelled.
“Everyone knew Charlie as a grazier and that,” Peter said.
Walk Cool had already strung together a double figure number of victories before Peter rode him successfully for the first time on race day.
Popular former hoop Lyall Appo got the job on the galloper before Peter did, scoring at Bundaberg in June of 1989 over the sprint trip at his first opportunity.
Appo had three more rides on Walk Cool, grabbing two more victories at Eidsvold and Gayndah.
Sinclair did not train his pride and joy at a race track, he prepared him at his property which was between Monto and Eidsvold.
They were good times when the Appo and Sinclair team would return home following a winning day at the track.
“When we would come home from the races at 'Bundy' or Gayndah, Saturday night’s in Eidsvold – I was the king,” Appo said with a laugh.
“Charlie was a big-time station owner and he shouted everyone.”
As the winners pile up, the weight from the handicappers' soon follow.