Ngokwe-radius yayo ye-curvature, kunemisebe ende ye-elbow ne-radius radius elbow. I-Long Radius Elbow ibhekisela kwimisebe yayo ye-curvature ilingana nezikhathi eziyi-1.5 ububanzi obungaphandle kwepayipi, okungukuthi, r = 1.5D; I-radius radius elbow isho ukuthi irediyo yayo ye-curvature ilingana nobubanzi obungaphandle kwepayipi, okungukuthi, r = 1.0D. (D ububanzi be-elvature).