Secondary Propulsion. Yes – TURBINES!

19 March 2021

In as much as Newtonian physics were employed for spaceflight in the re-imagined series, there was also provision for secondary propulsion in the form of jet engines, to supplement the extra thrust required for atmospheric flight.

This is the Baz version.

I had intended to use a high-speed motor of some sort and gear it down to required revolutions per minute, (RPM) to make it look good, but remain safe, should someone happen to poke something into them.

As I was intending to use the rear bearing off bicycle axles behind each fan, some friends of mine came over and suggested that instead of using one for each fan, why not use one bicycle to drive a central drive shaft, (master) – then pulley and belt drive all other shafts from there. This saves me having to put a motor on every fan as well. It’s a little extra engineering, but I am up for he challenge! as the front and rear fans are not in alignment, it is difficult to drive them from one shaft, unless I use universal joints or other. So, I decided to have each fan on it’s own axle with pulley, then link all to the pulley pack on the master drive shaft.

I’ve also had to replace the original wooden intake fans I made with aluminium, as they were warping and peeling badly. A friend of mine had some old road signs laying around so i asked if I could have a couple. They were the perfect size and thickness to create the blades. After some nights thinking and trying to simplify my engineering plans, I came up with a simple way to secure and install the bearings to hold the drive shafts. Luckily I have a basic lathe and even more basic turning skills, so I was able to figure out some simple couplings to join everything solid, flat and square.

4 May 2021

Finally, the motor has arrived. It’s a low speed, high torque industrial rotisserie motor. I installed all the drive shafts on bearings and connected the fans. Then I constructed my own pulleys out of craftwood with steel arbours and grub screws for adjustment. To couple the round motor axle to the square bike gear axle, I forged one end of a steel round tube into a square, then flared it to fit. I am using 6mm static nylon rope for temporary belts to get the show on the road, but there is still some tweaking to do.

Below are sound and motion tests, starting up the motor and sound effects speakers in the engine nacelles.