Torque vs. HP
Instructor
Joined: Sep 2002
Posts: 178
Likes: 0
From: Huntsville AL
Re: Torque vs. HP (MSR)
Make with the clickage for a whole plethora of information on rocket thrust. I don't have the time at this very moment to check and see if I was right or wrong in my rocket thrust statement. :) I'll check later. :smash:
Advanced
Joined: Sep 2002
Posts: 61
Likes: 0
From: Chaptico MD
Re: Torque vs. HP (MSR)
Do we know that this is true?
"if thrust is constant, then the time to accelerate a given amount is the same no matter how fast you're going"
If we drop the 10lb. cannon ball from the tower, gravity is constant, the acceleration is constant, 32fps/sec, will KE gain be the same for each second?
[Modified by antenna, 6:10 PM 4/9/2003]
"if thrust is constant, then the time to accelerate a given amount is the same no matter how fast you're going"
If we drop the 10lb. cannon ball from the tower, gravity is constant, the acceleration is constant, 32fps/sec, will KE gain be the same for each second?
[Modified by antenna, 6:10 PM 4/9/2003]
Burning Brakes
Joined: Nov 2001
Posts: 1,241
Likes: 9
From: Houston TX
Re: Torque vs. HP (antenna)
If we drop the 10lb. cannon ball from the tower, gravity is constant, the acceleration is constant, 32fps/sec, will KE gain be the same for each second?
the cannon ball is gaining in KE what it loses in PE, and PE goes by square of the distance (distance in the gravity part times distance in height).
PE = mgh
KE = 1/2mv^2
gravity is just velocity over time, velocity squared is meters time gravity, height is meters, so it all works and cancels properly.
meaning, the faster something drops, the faster the conversion of PE into KE. or, more PE is lost in a given unit of time as the ball falls faster, so yes, the power level of PE conversion increases with time.
but, hey, that's an excellent point. this is why these discussions are valuable. we can challenge each other's views, and we have to expand and learn in order to argue our position. i had never actually considered that, so when i first read your question, i didn't understand how the power could be increasing. (after some thought, i realized i didn't have to eat any crow.)
the rocket is different. the PE is the energy content of the fuel. so to increase the rate of PE conversion, you'd have to increase burn rate.
maybe they're not so different, after all... no, no, they're different. the rocket answer is all in terms of KE, no PE in there.
Burning Brakes
Joined: Nov 2001
Posts: 1,241
Likes: 9
From: Houston TX
Re: Torque vs. HP (antenna)
I don't have a problem with his last statement. I think he's writing for a basic HP-101 crowd and he wants to state it in a few ways. Torque at the wheels or torque at road speed is a way to take all the gear reductions into consideration.
I think this text is a fairly painless way for folks to learn about HP/Torque. From time to time I see these threads, with guys spouting all kinds of voodoo about HP and torque. If they would only read this text they would see the science of the measurements.
I think this text is a fairly painless way for folks to learn about HP/Torque. From time to time I see these threads, with guys spouting all kinds of voodoo about HP and torque. If they would only read this text they would see the science of the measurements.
Instructor
Joined: Mar 2002
Posts: 239
Likes: 0
From: Fredericksburg VA
Re: Torque vs. HP (MSR)
I made an Excel spreadsheet to help my membership calculate shift points. It also allows for an interesting comparison of the acceleration of a car with different engines and gears. You can see what the power band really does for you. I pulled all the aero loss, drivetrain loss, power used for rotational acceleration of things, etc. out of this spreadsheet. But it still demonstrates the point you are arguing over.
Send me an Email if you want the spreadsheet. Tell me what version of Excel you have, too.
Send me an Email if you want the spreadsheet. Tell me what version of Excel you have, too.
