Torque vs Horsepower

[origami_itto]

Also lego engineering

[everything]

Maybe Engineering Explained said something like - when you mash down on your bicycle pedal if the bike is in a higher gear and pointed uphill, you need higher torque to get going. It's hard to think about the rest without power to weight ratio and friction, fwd vs. rwd vs. awd, etc.

[origami_itto]

Did you watch the videos? Pretty cool demonstrations IMHO.

[everything]

Yup watched the first.

Which basically says “use gears” right?

This is why high HP low torque Hondas can accelerate well from rolls (but not “digs”) when combined with low weight so are popular for track applications.

But they wouldn’t be able to tow anything.

The big rigs that can tow can’t race like an Ariel Atom.


I don’t know how to understand that without weight in the picture.

[origami_itto]

I mean it's less about "use gears" IMHO and more like "check out this cool direct and practical illustration of the principle"

Now the second video... that has a definite message. "When engineering hits a limit... cheat"

[everything]

ah I think I've seen this channel. maybe you posted another one where the LEGO car crosses a sketchy LEGO bridge after various modifications (and then the obstacles get more difficult as well)? Basically it's cheating, yeah. But shows cool physics in application and why you'd have certain design features.

[origami_itto]

I saw the second one before but that's the only contact I remember.

[Dmitri]

Fascinating, how different people are
The first video was, to me, not clear (or "cool direct and practical") in the slightest, and had a ton of unnecessary fluff in it that should have been edited out.

This is infinitely better, IMO:

[origami_itto]

4 minutes more talking and no demonstration is LESS fluff?

People are definitely interesting.

I liked: "Here are two identical cars with identical power performing identically" "here they are failing to pull a load" "here's what happens when we gear down"

Dude is getting into power formulas and graphs and has two completely different scale model race cars on the desk that serve no purpose?

HOW DOES YOUR BRAIN WORK??? lmfao

[everything]

the EE video is difficult for me, probably because the topic is difficult. it's hard to say "if mass is equal". also, the HP has the time component, which is hard to understand as well. then he talks about gearing to have the high HP motor make more TQ. that's why I think of it as big truck vs. honda civic. one can tow but not go fast round a track. other can go fast around a track (in certain variants or with mods), but not tow (but yes yes has way lighter weight, better handling, etc. so it's so hard to completely "get it").

or i think about it as: starting your bicycle in a higher gear going up a hill needs more torque (from your leg). getting your bicycle to go faster on a flat section in that higher gear needs horsepower. that's as much as I can do the ELI5 thing for it.

[Steve James]

or i think about it as: starting your bicycle in a higher gear going up a hill needs more torque (from your leg). getting your bicycle to go faster on a flat section in that higher gear needs horsepower. that's as much as I can do the ELI5 thing for it.

From the cyclist's perspective, 'power' is measured in watts. So, pick any gear. On the flat it will take X amount of watts to turn the crank 360 degrees. Raise the incline, with the same gear, it will take more watts (which is a result of the necessary increase in "torque." However, if the gear is lowered, the watts needed to turn the crank, will require less "torque." That's why there are gears, and the optimal gear is the one that minimizes the amount of watts needed.

Torque is usually related to horsepower, in cars and trucks such as in the last video's diagram. Yeah, a tow truck might have 1000hp, and an f1 might have the same. But, one can go 200+ mph, and the other can pull 5 tons.

[origami_itto]

the EE video is difficult for me, probably because the topic is difficult. it's hard to say "if mass is equal". also, the HP has the time component, which is hard to understand as well. then he talks about gearing to have the high HP motor make more TQ. that's why I think of it as big truck vs. honda civic. one can tow but not go fast round a track. other can go fast around a track (in certain variants or with mods), but not tow (but yes yes has way lighter weight, better handling, etc. so it's so hard to completely "get it").

or i think about it as: starting your bicycle in a higher gear going up a hill needs more torque (from your leg). getting your bicycle to go faster on a flat section in that higher gear needs horsepower. that's as much as I can do the ELI5 thing for it.

There's a lot of ways to think about it, it all comes down to leverage essentially. By increasing the distance from the fulcrum you trade force for distance. You cover a larger amount of distance by applying a smaller amount of force to move a larger load by a smaller amount.

So like if you have a 1:1 lever you have to apply the same amount of movement and force on one side as you get out of the other side. If you increase the length of the force arm and make it 2:1 then you have to move it twice as much with half the force to get half the movement with twice the force.

Think about it like a record player, if you put your finger next to the spindle versus on the edge, how much effort/movement do you need to put in to get the same result.

How much FASTER does the outside edge move with the same speed of movement applied to the inside?

https://www.school-for-champions.com/ma ... assess.htm

Now if you consider Taijiquan in the context of the classes of levers, when we set up a system of fulcrums and loads by joining with someone, we can change the fulcrum and load locations of that system to rob them of their strength and throw them out.

And it's all levers. Wheels and circles and spirals are just applications of the lever.

[everything]

for the cycling one, i think they also say you can "spin" or "grind" (might be for an uphill context). the first seems more like "horsepower", the second seems more like "torque". this is probably wrong or not quite right, but if the "intuition is correct", it's good enough for me for this topic.

[Steve James]

Hmm, imo, the difference between spinning and grinding isn't torque. If we're talking about 'work,' spinning divides the effort (energy used) to move the bike. A cyclist only has X number of watts to use in a race. Spinning and grinding also refers to pedaling techniques. Chris Froome, for ex., is a spinner (plus he rarely gets out of the saddle). Otoh, sprinters are usually grinders. Their problem is saving enough energy at the end of the race. Yes, Cavendish in a sprint will generate more torque.

Power, torque, and work have to be considered together. Afa cycling, though, the length of the crank arm will have a definite effect on the torque measured. I.e., the length of the lever is critical. It's the same difference as if you'd try turn a nut by holding the wrench at the head or at the handle.

[everything]

i think of the spinning as hp because the hp is torque applied fast (roughly what the EE guy says, i think). it seems like it's the same as the honda vs the truck. might not know what spinning is. hondas (old school one w/o turbo) have to rev high to have any bit of power. the watts part sounds like it's more like the fuel (in the car example). once i was interested in mechanical engineering, but even the bicycle example is too difficult, lol