🎠 Chair-Swing Carousel: step-by-step build

Crank faster and faster — the chairs fly out wider and wider!

At the fair there is a ride where the chairs hang on chains and fly out as the ride spins. Wheee! Your carousel has four swinging chairs on a turntable, high up on two towers. Under the turntable a giant gear speeds up your cranking, and two corner gears send the spin up to the ride. Spin slowly and the chairs hang down; spin fast and they swing way out!

Level 2 of 5 (easy)
About 35 minutes
16 steps, 52 parts
Powered by: Hand-crank
Series: Mechanical Wonders

What you will learn

Turntables: A turntable lets a whole model spin round.
Bevel Gears: Around the Corner: Slanted gears send spinning power around a corner.
Gear Ratio: Fast or Slow: A big gear turning a small gear makes it spin faster.
Centre of Gravity: Keep the heavy stuff low and in the middle and your model won't tip.
Frames: A frame is a ready-made strong rectangle.

Build these first

🌬️ Bevel-Gear Windmill: Turn the handwheel at the bottom — the sails spin at the top! (level 3 of 5, about 25 minutes, 16 steps)
📡 Spinning Radar: A motor-driven radar dish that sweeps round and round on a turntable — with a blinking light. (level 3 of 5, about 25 minutes, 15 steps)

Parts you need

1 × H frame 7×11
4 × Blue long pin
3 × Split pin block
4 × Black pin (grippy)
6 × Red axle-pin
2 × Beam 9
1 × Axle 6
5 × Half bush
2 × Axle 7
1 × Giant gear (40 teeth)
1 × Hand crank
1 × Axle 4
1 × Corner gear (12 teeth)
1 × Tiny gear (8 teeth)
2 × Bush
1 × Turntable
1 × Corner gear (20 teeth)
1 × Medium gear (24 teeth)
2 × Beam 7
4 × Axle-hole connector
4 × Grey pin (smooth)
4 × L-beam 2×4

Steps

Lay the H-frame flat.
Push blue long pins up into the left rail, one hole each side of the middle, and press two split pin blocks onto them, one on top of the other.
Right rail: push black pins up one hole each side of the middle and press a split pin block onto them.
Push a red axle pin into the lower left block, pointing in, and press a 9-hole tower onto it.
Hold the second tower in place on the right. Push a red axle pin in through the right block into its bottom hole. Then push a 6-long axle from the left through the upper left block, both towers' 2nd holes and a half bush in between.
Push a 7-long axle through the 4th holes of both towers, with a half bush just inside the right tower. Add the giant 40-tooth gear outside and push the red crank on right against it.
Push a 4-long axle through the right tower's 7th hole from the inside, with a corner gear and then a half bush on its inside end.
Outside the tower, slide a tiny 8-tooth gear onto the axle, meshing with the giant gear, and lock it with a bush.
Put the turntable on top of the towers.
Slide a half bush, the big corner gear and a bush onto a 7-long axle and push it up into the middle of the turntable, so the corner gears mesh.
Put a 24-tooth gear on the axle as the hub. Push black pins into the two gear holes left and right of the axle, and press a 7-hole arm onto them.
Push two blue long pins down through the hub gear's front and back holes and cross the second arm on top. Lock the axle on top with a half bush.
Push a red axle-pin, pin end first, up into the right arm's end hole. Press an axle-hole connector onto its axle end, then hang the red chair on it with a smooth grey pin.
Same on the left arm tip: red axle-pin up into the end hole, axle-hole connector on its axle end, and the blue chair on a smooth grey pin.
Same on the front arm tip: red axle-pin up into the end hole, axle-hole connector on its axle end, and the yellow chair on a smooth grey pin.
Same on the back arm tip: red axle-pin up into the end hole, axle-hole connector on its axle end, and the green chair on a smooth grey pin.

Play time

Crank slowly — do the chairs swing out? Now crank fast! Watch how far out they fly. Take one chair off: does the ride still spin smoothly?

Real-world inspiration

Chair-o-plane / wave swinger fairground ride — https://en.wikipedia.org/wiki/Wave_Swinger