To ensure that your props are balanced in pitch, you need a pitch gauge to use when setting the blades on the spar.
Commercial pitch gauges are expensive, so I made my own out of balsa. The paper scale was worked out using a computer for the hub to slider distance. The scale was drawn using a CAD program. The paper scale can be stuck directly onto the top of the base.
The only parts which need special care are getting the block square in all directions and at the right place on the base.
I have made a small wire clip which holds the prop shaft in place to keep the spar square to the slider while setting the blade.
To use the gauge, just fit the prop shaft to the spar, push it hard up against the stop on the block (holding in plce with the clip). The prop shaft should rest on the small notch in the centre of the slider. Glue the blade to the spar with PVA, making sure that you have set it at the right distance from the hub to give the diameter you require. Let the blade set, turn the whole prop around and set the second blade. If you have balanced the blade weights, you should have a really smooth running prop, which uses no energy in wobbling!
Just print out the download from here by clicking or tapping on the pic below and saving it to your computer. print on A4 paper and ignore any error messages about clipping!
Tom Tomlinson
Commercial pitch gauges are expensive, so I made my own out of balsa. The paper scale was worked out using a computer for the hub to slider distance. The scale was drawn using a CAD program. The paper scale can be stuck directly onto the top of the base.
The only parts which need special care are getting the block square in all directions and at the right place on the base.
I have made a small wire clip which holds the prop shaft in place to keep the spar square to the slider while setting the blade.
To use the gauge, just fit the prop shaft to the spar, push it hard up against the stop on the block (holding in plce with the clip). The prop shaft should rest on the small notch in the centre of the slider. Glue the blade to the spar with PVA, making sure that you have set it at the right distance from the hub to give the diameter you require. Let the blade set, turn the whole prop around and set the second blade. If you have balanced the blade weights, you should have a really smooth running prop, which uses no energy in wobbling!
Just print out the download from here by clicking or tapping on the pic below and saving it to your computer. print on A4 paper and ignore any error messages about clipping!
Tom Tomlinson
Easy to make balsa pitch gauge
