Mike,
Those Stainless Steel propellers look like one of my X-450/2 just "SUPERSIZED". I like the finish
on them too. Must be some serious power, do you see how much the hub and trailing edge are
built up?
Nice photos,
Mark Sholund
Mark,
The props in the photos are a 10.5" diameter x 16" pitch. We are now actually using a 10.75" x 16", but they look the same. The heavy hubs and thick trailing edges are for strength. Even with this, the prop ears push forward overtime. The finish is a dull, sanded one - not polished.
Jim,
The engine turns 8,000 to 8,500 rpm at the end of run. The W drive has gears that over drive the props. In our case we are using a 1:2.36 ratio. So therefore the prop speeds at then end of a 1/4 mile are around 20,000 rpm.
Terry,
The props are a cleaver design. We chose to round the blade tips. When we first went to the twin prop setup, we had an issue with the props giving too much lift on the start. The nose of the boat would be buried in the water on the start. The first time out it actually went under for a moment. Anyway, we ended up shortening the length of the drive shaft - thus pulling the props under the boat more. The boat uses a solid 1.25" diameter drive shaft - no flex shaft. We also rounded the ears of the props. This is something that drag boaters have done in the past to kill lift. We had nothing to loose and needed to try something so we tried it. I cannot figure out why rounding the ears works. It seems like it would give more lift. Andy Brown - any thoughts?? It worked though and we have done it since. Hopefully this year we will try the pointed tips again to see if it was the blade shape or shorter shaft length that made the difference.
Andy,
Right now we are planning on going to Augusta.
As Andy mentions, the counter rotating props help reduce prop walk. I listed the leg on the ET record wrong. It was 4.762 second, not 4.672. It was getting late when I typed it in last night...
Mike
