variable-pitch propeller(A controllable pitch propeller (CPP) or variable pitch propeller is a special type of propeller with blades that can be rotated around their long axis to ... wiki – ВИШ Alexander Demidov)
spaced some distance apart(Dig a trench that is 6-8 inches deep. Plant each piece of potato (cut side down, with the eyes pointing up) every 12-15 inches, with the rows spaced 3 feet apart.)
