One of the most common questions we're asked is what is the difference between a 3-blade and 4-blade propeller, and which one is right for me. Outside of the specific diameter, pitch and cup of a propeller, this is definitely the most common question, and the first one that we're asked as customers begin the prop buying process.
Theoretically, a 3-blade propeller should always be more efficient than a 4-blade. However, two big issues have prevented the 3-blade from taking the lead in popularity. The first was a lack of manufacturing precision, which commonly caused 3-blades to vibrate more than 4-blades. When significant dimensional variation exists in a propeller, vibration is generally more noticeable in a propeller with fewer blades. The second reason for the 3-blade disfavor was an almost certain loss of blade area in the transition from four blades to three. Consequently, even though top-end gains were achieved, performance expectations on the low-end were diminished.
Through the implementation of precision manufacturing and design improvements, Acme and OJ Propellers are giving the 3-blade the reputation it deserves. Acme and OJ are consistently holding tolerances never before achieved in propeller production. This accuracy makes the 3-blade incredibly smooth. In addition, the blade area of the 3-blade has been expanded to equal that of the 4-blade. The translation? The 3-blade has raised the performance bar. From an awesome hole-shot to an unmatched top end, and all the smoothness throughout, the 3-blade leaves nothing to be desired. We believe it has an edge that everyone will appreciate. On the other hand, please do not mistake our excitement as a lack of appreciation for the 4-blade, a proven winner.
It should be noted that this choice might still be mildly influenced by the application because it's possible that the most perceptive users might be able to detect slight differences that cause them to prefer one prop over the other. Even still, the overall performance of either the Acme or OJ Propeller is superior.