It consisted of having the counterweights flexibly mounted instead of being rigidly bolted, as was common practice.
"The First Airplane Diesel Engine: Packard Model DR-980 of 1928"
Robert B. Meyer
"See, Gladys, I have a horse out here," and Faith went to where the low-growing limb of a pine sprang flexibly as she leaped upon it into an imaginary side-saddle.
"Jewel's Story Book"
Clara Louise Burnham
But his home is not so interesting as that of the houseboatman, nor so picturesque as that of the raftsman, whose floor of logs rocks flexibly under his shanty, but securely rides the current.
"Short Stories and Essays From "Literature and Life""
William Dean Howells