- Created on Saturday, 03 August 2013 17:56
Time for some proto test results!
Proto 1 propeller
Not much to say about this one. We did a initial test run with this propeller, and found out that our very first boat drag guess was off by a lot. The acceleration was slower than the "quality aftermarket" stainless propeller we were comparing to, and we only got about a 0-1km/h top speed improvement.
We were quite surprised with the top speed increase, even though our design values where off by quite a lot. This raised hopes that our design had some serious potential, with quite a different design philosophy compared to propellers on the market now.
But we did get valuable test data, as well as realizing we would need more accurate GPS data to evaluate the results better.
Proto 2 propeller
Now we had a serious propeller, with a design based on actual speed and slip values from the boat we were testing on. Our confidence level was much higher than with the proto 1 propeller. The manufacturing process we use, allowing for super-thin blades, really changes the way you can look at the design process.
And the awesome test results. They are not fully valid though, since the engine was pulling much more rpm with our proto 2 propeller than with the benchmark. And we had no idea of what the powerband on our 45hp 4-stroke Honda engine looked like. But anyway, a serious speed increase:
Proto 3 propeller
With this propeller we wanted to get the engine running at the same rpm as the reference prop. 15.7" of pitch was just right! 6000rpm with a tailwind, and about 5800rpm in a headwind, with both our proto 3, and the reference prop.
That means this is a genuine, fully comparable result. Our proto3, 6-blade billet CNC aluminum propeller accelerates faster, and gives a average of 2km/h top speed increase over a high quality cupped stainless steel propeller. Huge!