non-retractable tail wheel
tail wheel landing gear
tail wheel position indicator
cat-tail common cat-tail
scouring wheel and buffing wheel
sprocket ; sprocket-wheel ; sprocket gear ; chain wheel
sprocket sprocket-wheel sprocket gear chain wheel
wheel turning lathe not needing to take wheel off the bogie
automatic steerable antenna
digitally steerable line array loudspeaker systems
electronic steerable array radar