Kev tuav lub nplhaib hom

Muaj plaub yam tseem ceeb ntawm cov rings ruaj khov muaj, txhua tus tuaj yeem muab faib ua cov subtypes raws li cov ntawv thov tshwj xeeb:
conical feem
Axial sib dhos
kev hloov pauv
Inclined dav hlau
Hneev
Radial sib dhos
Kev xauv tus kheej
Tsau ib feem
ntsia hlau
Circular propulsion