Reply With QuoteSo when will I be convinced?
LVjetboy:
Builder,
I never said torque was unnecessary after water gets flowing, in fact torque will still be there. Unless you have no friction or losses and no acceleration? Pretty unlikely for jets or anything else in the real world.
On the "torque moves mass" thingy. A common mantra echoed by many in an attempt to answer the dilemma. But think about it, what does that really mean? Torque doesn't do sh*t unless there's motion. Consider the rusted bolt. Turns out the "motion" part, and exactly how fast that motion is, is a more important consideration to performance in the end. The statement "torque moves mass" is a catchy phrase, sounds pretty good, but doesn't go very far in explaining whether we should focus on power or torque to determine jet boat performance. The focus of this thread.
Turns out jets are more like rockets when it comes to performance. Ever try'n figure out the torque of a rocket? There is none of course. Just power and thrust modified by mass = acceleration. Think about it. Study it if you must.
Yes, in the real world, if there's circular motion involved, you'll also have torque applied. And guess what? You'll also have power applied. The question is, "Which term best describes the performance of that circular motion?" Turns out power. Because power not only describes how much muscle (torque) is applied but also how fast that muscle is being applied. This is a key point. Not explained by the "torque moves mass" mantra. And it turns out, also not a trivial thing in the performance world.
So too in the jet boat world. You focus on torque alone you get half the story. Not that you get nothing, only that you get half the story.
You focus on power and you get the whole story. That being both the amount of torque and the rate at which that torque is applied...not a trivial thing when talking about overall system performance i.e., the speed of a jet hooked to an engine with certain power capabilities.
jer
