His English language Wikipedia entry is skimpy, so consider linking here to his French entry.
As can be seen in the images below, Ham chose to exaggerate shapes of cars and planes when they were depicted in action. However, he was capable of more representational depiction when he so chose.
For what little it's worth, I am not a big fan of the sketchy, exaggerated French style of illustration seen from the 1930s into the 1950s and even beyond. I think that Walter Gotschke, who I wrote about here, did a better job of depicting racing cars impressionistically.
First, three examples of Ham's poster work at the height of his career -- for the Monaco Grand Prix race.