We ship lots of Squirrel kits to Australia but there are a lot of DIYers there.
Keith Harbottle is setting up a High School Camp and he was not able to source the 5″ propeller.
The Squirrel should work fine on a 4″ propeller. The workshop is being deployed this week so we may get some more pictures.
Below are a couple of his experiments. He made a smaller Squirrel to see if it worked better with the 4″ propeller but I think he will find it’s much easier to just make a standard Squirrel then substitute propeller.
I’m curious if those 4″ propellers turn in the opposite direction. 🙂