Question

How much horsepower would a car need to tow the a boat up the industry standard: Davis Dam Grade Climb?

•grade = 7%•Air density (.002377 slugs/f^t3) •w(weight) 4451 Lbs •Crr = coefficient of rolling resistance = .015 •Assume Combined CDA is 1555 ft^2 •SAE J2807 (Davis Dam Grande Climb) - min speed is 40mpg (59 ft/s) •F(drag) = 1/2p x V^2 x C(d)A •F(rolling resistance) = W x cos x Crr •F(weight) = W x sin •F(sum) = F(drag) + F(rr) + F(weight) •P = F(sum)XV •convert to horsepower = P(1hp/550ft lbf/sec)

Answer 1

Since no additional weight is given here except 4451 lbs we will proceed with having the total weight as 4451 lbs.

Horse Power = P/550 = 401794.72/550 = 730.5358 HP (Ans).