Show T Fork I Tuning Shimmy Taken Out of Biplane WASHINGTON April 30 UP Mysterious rIo airplane vibrations which stunt and military fliers Illers reported d Were pulling the fillings out of their teeth have b been e identified Idem idea titled and overcome two overcome two national bureau of standards experts expert told the American Ame can society Physical to to- day L L. B. B Tuckerman and Walter Ramberg found the trouble was as due to s resonance or fractional al vibrations The difficulties difficulties dUn dUn- dUnI I can be corrected by adding alIght slight to each wing tip Tuckerman said such luch vibrations were found only in biplanes The wings apparently act as huge hUie tuning forks ho said Five pounds of extra weight added to the tips Up forks threw the two wings or out of balance thus eliminating the vibrations |