Related by context. Frequent words. (Click for all words.) 51 helicopter rotor blades 49 helicopter rotors 48 airfoils 48 egg beater 48 propellers 47 rotors 47 propeller 46 flapping wings 46 rotating blades 46 armatures 46 spinning blades 46 vanes 46 rotor blades 45 periscopes 45 propeller blades 45 tuning forks 45 fluting 45 phalluses 45 tuning pegs 45 tail fins 44 erector set 44 magnetron 44 eggbeater 44 hydraulic motors 44 snare drums 44 treadle 44 splines 44 charkha 44 phonographs 44 pendulums 44 wooden dowels 44 whirr 44 corkscrewing 43 whirligigs 43 tailfins 43 electromagnet 43 blades 43 electromagnets 43 batwing 43 magneto 43 whirrs 43 spiderwebs 42 airfoil 42 numerically controlled 42 windmill blades 42 lathe 42 windsocks 42 whirling 42 propellor 42 papier maché 42 knurled 42 venturi 42 Tesla coil 42 Volkswagen Beetles 42 contraptions 42 whooshing 41 ailerons 41 wingtips 41 Singer sewing machine 41 biplanes 41 rotor 41 duck decoys 41 electromagnetic induction 41 pasteboard 41 vacuum tube 41 cowls 41 tuning fork 41 earthward 41 edgers 41 Popsicle stick 41 laminar 41 louver 41 miniature 41 Stocking distributor 40 andirons 40 vibrating 40 wooden slats 40 clanking 40 antiaircraft guns 40 turbojet 40 plasma cutter 40 protuberances 40 piezo 40 Typewriters 40 unpowered 40 hydraulic rams 40 turbine blade 40 toylike 40 strobing 40 Gatling gun 40 Theremin 40 pulleys 40 pushrod 40 turbofan engine 40 teardrop shaped 40 dot matrix printer 40 geodesic domes 40 nailers 40 vacuum tubes 40 barber pole 40 boomerang shaped