Apart from all the regular work ongoing, we've been looking further at testing the brakes - see the update a couple of weeks ago with the handbrake tests. This week we've tested the power brake, principally to confirm that the force expected at the brake blocks is correct. This comprises a series of calculations working through the system from the brake cylinder to the blocks and is nothing more than GCSE physics level calcs; air pressure acting on a piston; resultant force acting on a series of levers and finishing at the brake blocks.

To confirm the design calcs, we used a pressure gauge on the brake cylinder to measure the force on the piston and a modified brake block to measure the resultant force.

The photo below shows the modified brake block in position, two load cells are used so that the block remains steady; the force measured at each cell is added to get the total block force.