Mr. Piper and His Cubs (© 1973 The Iowa State University Press, author Devon Francis) Page 62, second last paragraph:
"There was a fourth brand of engine, the three-cylinder Lenape radial. While it was a livelier piece of machinery than the flat fours, it had vibrations that were harrowing. Piper never mounted more than a baker's dozen Lenapes on the noses of Cubs."
That being said, beginning on p. 65, and continuing to the next page is a tale of the Piper Aircraft publicity department's stunt of having a couple of it's pilots fly a Lenape powered Cub (NC20280) non-stop between Newark NJ and Miami FL in 1938 to commemorate the 20th anniversary of the inauguration of air-mail service by the US Army in 1918. Refueling was accomplished by letting down a rope from the Cub, and folks in autos and pick-up trucks tying on gas cans to be hauled up. (Interesting aside: apparently Fords were better able to accelerate, and were preferred over a Chevy for the job)
Summation quote from the book: "Kress and Englert had flown 2,390 miles nonstop, not counting the orbits at Jacksonville, behind an engine that shook their eyeteeth. Aloft for sixty-three hours and fifty-four minutes, they were bone tired. "Good show," pronounced the Piper press department. It made all the newspapers"
... ahh the "Good ol' Days.."