On our smaller whippers we've used a piece of all-thread and a swivel foot, which has allowed for any prop angle adjustment we saw fit. I don't have a great image of any of them, but the attached is from Janus, and worked well. The silver arm on the left is the throwing arm, and the black arm is the hanger arm, the picture is shown with the machine cocked. Threading the foot further in or out changed the prop angle nicely.
I agree with Thomas that you likely need to increase the prop angle. Typical arm-hanger separation is usually in the 30-35 degree range in my experience, it at least makes for a good starting point.
- Adjustable prop foot
- prelim_adjustable_prop.jpg (57.11 KiB) Viewed 19154 times