Revolution is one of the best designed 4-blade propeller which is recommended for engines above 200 hp. The large surface area of its blades, the aggressive cupping and the high raked blades are the main characteristics due to which its performance is enviable.
It is available in 14 5/8" diameter and in pitches ranging from 15" through 25", in 2" increments. The purpose of this article is to show in practice the differences which arise in the performance of the below rib, but also of our engine, when we change the pitch of Revolution by 2 inches.
So we tested a Revolution 19" and a Revolution 21" pitch on a Top Line 23 to which a Verado 200hp was mounted.
The tests took place at the same time, in the same direction, with the same load so as to be able to determine precisely the differences in performance of the two propellers.
We should note that the tests were done with the rib much more loaded because we wanted to see the behavior of Revolution under great loads.
First of all we must emphasize that the Revolution suits extremely in this boat-engine combination for all around use and its performance is far better than any other prop.
Observing the table above we can easily see that the Revolution 21":
- gave us higher speeds, by 3 or 4 knots, over the whole rpm range. This means that we have higher top speed, higher cruising speeds and we are able to travel faster at very low rpm, having our engine working less, which is very important when we cover long distances
- gave us lower fuel consumptions almost over the whole rpm range
- showed much lower slippage over the whole speed range
- allowed the rib to reach 47 knots at full throttle while it was turning 6000 rpm, ie 400 rpm less than 19" one. So, the overall rule according to which every inch of pitch «costs» to the engine 150-200 rpm is confirmed
Below we’ll find detailed measurements of both propellers
Taking on our tests we found that for every 100 litters we lightened the rib, the engine was turning a hundred more revs, which means that with a load of 170 litters and 3 persons our engine can reach 6300 rpm at WOT.
There is no doubt that the propeller of choice in this boat-engine combination is the Revolution 21΄΄ because except of its much better numbers in all areas, is also allows the engine to turn within its rpm range at WOT, even when the rib is overloaded. This means that with fewer loads the engine will easily reach 6400 rpm that is its maximum speed.
We note that we can generalize the above data as we almost always find similar differences when we go from any shorter pitch propeller to a longer one, of the same brand of course. The results will be conversely when we go from a longer pitch propeller to a shorter one.
We are able therefore to know in advance the differences that we will wait in our performance, in most of the cases.