D. Gottlieb & Co.'s Humpty Dumpty (1947) was first machine to use flippers. Flippers are levers used to aim the ball and give it energy to roll up the playfield, countering the forces of gravity and friction. Levers turn a little mechanical energy into a much larger force to extend game play. Gottlieb’s Bowling Queen is an Electro Mechanical game (1964) with a scoring backbox animation of tiny bowling balls on a ramp.

Flipper Leverage

The best way to aim a pinball is to catch it on a flipper so it stops rolling. Position the ball along the flipper; flipping the ball when closer to the flipper tip sends it to the opposite side of the playfield. Try it. The flipper moves the ball in a perpendicular

(normal) direction to the side of the flipper. The force is proportional both to the dis-tance from the flipper pivot point to the ball impact point, and the angle through which the flipper rotates before releasing the ball. This is called a lever arm.

If the ball is still rolling when flipped, the flipper will also add spin, causing the ball to curve or bend away from the direction of normal force. Pinball wizards can bend

it like Beckham depending on whether they stop the pinball on the flipper first or hit it in motion. The remarkable thing is that we can develop an intuitive sense of how to use the flippers to play without being able to derive all the energy transfer or geo-metric calculations.

Bumper Switch

Bumpers aim the ball back at the player by squeezing down on the ball. When the ball hits the bumper, it closes a switch below it. The switch turns on a solenoid under the playfield that yanks down a metal cone above the ball. The force in this case acts tangentially to the surface of the

ball, spitting it out and spinning it at high speed.

Follow Bouncing Ball

©2018 Wackenhammer’s Clockwork STEAMuseum, all rights reserved. 541 Main Street, Hyannis, MA 02601. 774-810-9016

The Prof. Asks?

1. If you were a pinball designer, how would you design your flippers for more

interesting and challenging game play?

2. At what angle does a pinball bounce off the cylindrical center of a bumper?

catch aim

rolling aim

the

The science of play!

Switch

Solenoid

pulls upper

cone down