Long Tail Propellers
The goal in propeller selection is to determine what propeller style and size will maximize performance for your boat, while allowing your engine to operate in the recommended RPM range (optimized power band). The correct propeller will prevent the engine from over-revving, yet allow it to reach the preferred RPM where maximum horsepower, load carrying capacity and performance is produced. This mix may change depending on the users needs, boat, load, and engine. Elevation and environmental conditions also affect this computation.
When selecting a propeller it is important to first measure your intended use. If you normally run your boat with a fixed load you should select a propeller that delivers optimum RPM with that load. If you intend to run a heavy load in the fall, it is best to select a smaller pitch propeller or gearing so that you don't loose RPM and drop below your engine's preferred power band. If you intend to run in different climates and different elevations, propeller choices again will vary.
You can strive to get one propeller that does it all, or invest in a propeller for lighter loads and another for heavy.
Stock motors run best from 3800 to 4000 rpm. Black Death motors run best from 4000 to 4175 rpm, and the BPS mag engines run best in the 4400 to 4600 rpm range. Note: Mag engines are fitted with a 5100 RPM rev limiter and you can run these motors to this limit without question, however, best performance and engine life is achieved by operating the mag engines near 4600.
Many short tail motors like the Mud Buddy short tail series do not have a broad propeller selection, rather they rely on belt sprocket variations. Some mud motors like the Pro Drive have fixed gearing and the proper propeller selection is very important.
If you can change drive ratios, it is best to select a propeller and/or sprocket ratio combination that runs a bit slower with a new propeller so that the RPMs can increase as the propeller wears.
A one pitch change will result in a 250 to 350 rpm change.
When using these charts - select one pitch smaller prop, or one gear ratio smaller when running above 4000 foot elevation or when operating a larger than normal boat and load.
Super Longtail Electric Clutch Prop Selection Chart
|Engine||Propeller||Sprocket Size||Gear Ratio||RPM|
|Black Death 4500||9 1/2 X 9||40 top / 46 bottom||1.15:1||4200 - 4500|
|Stock 35||9 1/2 X 9||40/46||1.15:1||3900 - 4175|
|Stock 27||9 1/2 X 9||40/48||1.20:1||3800 - 4000|
|Long Tail Prop Selection Chart (3800 to 4000 RPM)|
|Mag45||10 X 8||Stock 18||9 X 5|
|Black Death 4500||10 X 8||Stock 14||8 X 4|
|Stock 35||10 X 5||Stock 12 Gear||10 X 8|
|Stock 27||9 X 7||Stock 13||8 X 4|
|Stock 25||9 X 7||Stock 9||7 X 4|
|Stock 24||9 X 6||Stock 6 Gear||9 X 7|
|Stock 23||9 X 5||Stock 6||6 X 4|