FYI - Cruising Speed Formula

[boater4life]

Here is a helpful formula for those that don't have a fuel meter.<br /><br />Cruising Speed Formula<br /><br /> Prop Size: _________<br /><br /> rpm----------mph--------rpm per mph<br /><br />2000 -------- _____ ---- _________<br /><br />2,500 ------- _____ ---- _________<br /><br />3,000 ------- _____ ---- _________<br /><br />3,500 ------- _____ ---- _________<br /><br />4,000 ------- _____ ---- _________<br /><br />4,500 ------- _____ ---- _________<br /><br />Begin plane and trim. Record speed at rpm, slowly advance throttle to next increment, continue to full throttle.<br /><br />Divide each rpm point by the miles-per-hour recorded. Result is how many revs it takes to maintain each mph. Calculations show exactly the most speed for the fewest rpms. Most fuel-efficient cruising speed is least rpm to generate each mile-per-hour.<br /><br />

 

[Franki]

Re: FYI - Cruising Speed Formula

Thats handy to know, thanks.....<br /><br />I guess it doesn't even matter if using speedo or gps... since the speed accuracy isn't important anyway.. more the difference in speed at each rpm increment. If you do it in the same place at the same time.. then that should be just as effective yes??? <br /><br />Currently I have no real idea what the cruzing speed of my boat is...<br /><br />rgds<br /><br />Franki

 

[boater4life]

Re: FYI - Cruising Speed Formula

It's best to pick a calm day and do the trials.