Message originally posted by John Robertson on 27-Sep-09 at 08:08 PM

Due to the damage caused to one rudder a couple of weeks ago, I decided to re-make all of the rudders using a new method I've been developing for some time (it's a quick and cheap way to make and fit rudders - more to follow ).

I decided to make 5 smaller width rudders to replace the barn-door sized ones I was using (three at 42" x 20" each). They ended up 12"x36" and I fitted them staggered in height (the lower one was at the centre to avoid the "dead" area at the prop hub - with the higher ones at the outside.). Building the rudders was very easy and quick and it didn't take long to fit them. However, making the cranked rudder bar was a major job (it has to be formed in three dimensions rather than the usual two dimension which added a whole new level of complexity ).

Anyhow, they got fitted to the craft along with new steering cables and a new (bicycle based) steering column. Nice and smooth!

I tested the setup in a field and it worked really well - much more rudder authority made the craft very easy to manoeuvre. On stationary hover, you could tip the top of the prop guard side to side 5 inches at full rudder deflection.

I then took the craft down to the coast to test on the river.

It was pretty windy (16-36mph ) - good if you want to test rudders! I was very impressed by the narrower rudders - no side wind problems (as happens with the larger rudders) and the craft was very easy to control in the blustery conditions.
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The rudders have around 10% LESS area in total than the larger plans rudders but provide better control and are less vulnerable to the wind - overall a success. I just need to check the durability of the new construction technique (although, at less than 5 and 10 minutes per rudder maybe it isn't that important ). One other advantage is that I've just shortened the craft by 8 inches!