Pounds thrust to horepower

[HTHM]

Is there a formula to calculate pounds thrust from an electric trolling motor to horsepower? The reason I ask is, I can get about the same speed from my gas motor as I can get from my trolling motor.

[brickNblock]

A great Q HTHman.....

I dont have an answer for ya tho pal.......

I'd sure like to know tho..from them do know???????

 

Mine dont work like your'n tho'

Got a 115 johnson main w/9.9 merc....

on the front end ive a 74lb minn kota..and have been wondering the same thing lately.

Its enough that in semi calm waters to not just steer but propell the boat whre i wish to go.

Great 'Q'

 

EDIT: wheres Wayne when you need him?

Edited May 30, 2008 by brickNblock

[jace]

Is there a formula to calculate pounds thrust from an electric trolling motor to horsepower? The reason I ask is, I can get about the same speed from my gas motor as I can get from my trolling motor.

 

 

simple answer, no. just like you can't calculate torque from the HP rating. generally speaking, the physically larger engine will have higher torque and much more push behind it which is why a 600HP 4cyl is useless for real get up and go off the line. For electric motors, it's comes from the amperage and, like gas engines, the physical size of the motor.

[John]

Torque x Engine Speed/5,252 = HP

 

eg., 200 pound feet of torque x 4000 rpm / 5,252 = 152 HP

 

The 5,252 number is a derivative of a series of calculations.

[Mike the Pike]

I have a 10 year old Minnkota Transom mount 46lbs of thrust with maximiser the motor has 3.1hp indicated on top of the motor.

 

[Guest skeeter99]

roughly

 

1 h.p. = 15lbs of thrust (on most applications)

 

 

 

so a 50# thrust motor would be roughly 3.6 h.p.

 

50lbs/15lbs=3.6 h.p.

[Tybo]

There is no true theory on hp to thrust.

 

HP= torque

Trust=propulsion

 

Thier is a way to get close though.

 

You need to know how much hp's and torque there is at the prop shaft and

the rpms. from this you can convert it in to kilowatts. Then from kws you

can convert to thust.

[forrest]

Here is a super informative link, unfortunately it was designed for rocket scientists:

 

http://www.aerospaceweb.org/question/propulsion/q0195.shtml