Airman 1st Class
- Aug 8, 2010
I just grabbed the 255/1600 numbers off of the wiki page for the SBD (-5 model), looking for a quick example to use. (Five point demerit for me for intellectual slot.) In my youth (a loonng time ago) I wondered why the "old" battleships (e.g. Perl Harbor) that had 25-28 knot top speeds could not be "juiced up" a little to match the 30-33 knot "fast" carriers. Then I learned that resistance (drag) is proportional to the square of the velocity. To increase the value of 'v', you have to overcome v*v^2 = v^3. I remember calculating (in physics class) the power increase required to go from 25knots to 30knots (1.73), which made it clear. It wasn't my greatest ephipony in life (such as there being no Santa Claus) but it impressed upon me the 'power' of the 'exponent' with regard to forces. (Unintentional pun.) It makes something like the receipt of radar echoes even more remarkable, since they decrease inversely to the FOURTH power, 1/d^2 going out and 1/d^2 coming back. This showed me the power of electronic resonance in circuits.Uh, Sam, the R-1820 gave 1000-1350 hp in various versions of the SBD. However, to your point, the speed never varied much. When they got the newer engines something was added (or several somethings) that added a bit more drag.
"How terrible is wisdom when it brings no profit to the wise."