If an engine with high horsepower can gear down to increase torque, couldn’t a high-torque engine be geared up to increase horsepower?

Question

Just wondering why, in these discussions, people always say the former and not the latter.

In: Engineering

Answer 1

Power is constant.  

 Speed and torque can be exchanged for each other. 

Think of it like two gears, a big one and a teeny tiny one. One can be the source and the other the output. One way you’re gearing down, spinning the little one to make the big one slowly turn a hand crushing torque. Or you’re spinning the big one to make the little one ZIP extremely fast into a blur…which you can stop with your pinky finger. 

That’s gearing. Total power remains constant, torque and speed change depending on gearing. 

I recommend reading The Way Things Work by David Macaulay. The first chapter will really hammer home how simple mechanics works. Enough to make my first year physics course almost unnecessary.