Making scale props that really work can be easier than you think,follow the full size manufacturers system and it will be easy for you to carve a realistic prop with just the pitch that you require.
For the sake of this exercise we will settle for a 12 inch prop,first of all cut yourself 12 pieces of wood ( obeche,ramin,pine,gelutong,basswood etc ) to a length of 12 inches by 3 eighths wide,drill the centres as a stacked pile with the centre to take a piece of screwed rod,now carefully apply adhesive to all of the laths ( PVA glue is fine ) and bolt up the centre,now carefully swing the pieces like a fan to get the desired pitch ( copy a commercial one if you like ) now clamp these together and allow to dry out properly.
Next step is to cut the prop side profile which can be determined by looking at the plan of the real ship,plane the edges down with a razorplane and then carve the blades to an aerofoil shape,dont take too much off one side only but keep swopping sides to make the cuts equal.
Finish off with medium grade glasspaper then drill the hub to your engine size,now is time to balance your masterpiece,if you are lucky to have a prop balancer then use it now,if not place a metal rod into the prop centre and place on two upright razor blades that have been pressed into a block of balsa,watch your fingers here ! and balance out,take material off the heavy blade until the blade balances horizontally.
Next give two coats of marine varnish and dont forget to re-balance before you use the prop,adding more varnish to the light side.
You will just love the way that the varnish brings out the grain in the wood of the prop together with the laminations.
Therapy rating= 9
For the sake of this exercise we will settle for a 12 inch prop,first of all cut yourself 12 pieces of wood ( obeche,ramin,pine,gelutong,basswood etc ) to a length of 12 inches by 3 eighths wide,drill the centres as a stacked pile with the centre to take a piece of screwed rod,now carefully apply adhesive to all of the laths ( PVA glue is fine ) and bolt up the centre,now carefully swing the pieces like a fan to get the desired pitch ( copy a commercial one if you like ) now clamp these together and allow to dry out properly.
Next step is to cut the prop side profile which can be determined by looking at the plan of the real ship,plane the edges down with a razorplane and then carve the blades to an aerofoil shape,dont take too much off one side only but keep swopping sides to make the cuts equal.
Finish off with medium grade glasspaper then drill the hub to your engine size,now is time to balance your masterpiece,if you are lucky to have a prop balancer then use it now,if not place a metal rod into the prop centre and place on two upright razor blades that have been pressed into a block of balsa,watch your fingers here ! and balance out,take material off the heavy blade until the blade balances horizontally.
Next give two coats of marine varnish and dont forget to re-balance before you use the prop,adding more varnish to the light side.
You will just love the way that the varnish brings out the grain in the wood of the prop together with the laminations.
Therapy rating= 9
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