Torque VS. Horsepower

[Bird]

I've been searching to see if I could find anything on the Internet and have not, but in the mid-70s, Winnebago ran some ads and there were stories in some of the RV magazines about the Winnebago/Sikorsky helicopter RV. If I remember right, they only made two of them; they didn't sell very well. /forums/images/graemlins/laugh.gif I think the price was about $250,000 and that was when you could buy a Bluebird motorhome for about $80,000. /forums/images/graemlins/laugh.gif

Well, I did find a place that says Winnebago introduced the Heli-Home at the national RV show in Louisville in 1976, but no picture.

 

[jmc]

shopintractors,

Your graphs are too small to read the units on my computer but in general, I think a flatter torque curve is better. You could design an engine that had disproportionately high torque in a very narrow RPM range and it would fool a lot of people. When they got it home they would notice that it also had disproportionately low torque outside the power band. (sweet spot) That's ok on a sports car with enough gears but probably not a tractor.

Also of interest is a term called "torque rise". The following is an explanation I stole after a quick google search:

{What?s So Important About Torque Rise?

Torque rise, or torque reserve, is a measure of lugging ability (low-end power) when the going gets tough and the engine revs down. If your engine came from the United Kingdom, specifications may refer to ?torque rise? as ?backup.?

General rule of thumb ? The more torque rise, the better! The engine may sound like it?s about to bog down and stall, but then it just keeps on churning, like the Energizer bunny.

You can feel, hear and mathematically see torque reserve. Your A.R.A.-affiliated rental expert can look up ?peak torque? and ?torque at rated horsepower? on the engine spec sheet. Then, to determine torque rise:

* Divide peak torque by torque at rated horsepower
* Carry it out to two decimals
* The answer will be ?1? followed by a two-digit number that represents torque rise, expressed by a percentage.
Example:
1.27 = 27 percent torque rise
A rating of 30 percent would be better yet
* High torque rise is especially important in such machines as articulated wheel loaders, for instance, which lug down as they burrow into a pile of dirt or begin to dig.
* On machines like excavators and backhoes, you can hear them respond to the increasing load as the crowd cylinder forces the dipperstick through the pass and the bucket curls into the dirt. If they stall out, they may not have the torque reserve to handle the load as it builds up.}

John

 

[gone]

ANdy your tourque to hp thing don't hold water with me. a gas @ 20hp doesn't have the tourqe a 20 hp diesil has, Fact or Fiction . diesels are very well known for a high tourqe rise. A for instance and i don't know exact #s but i'll be close a cummings same as dodge has,; in a ford f6oo the hpwas 230hp and tourqe was 600 ft.lbs my 150 has 225 hp and 290 ft lbs tourqe, so whats up with your formula now. id say a diesel produces more tourqe wouldn't you if im wrong explain it to me better?

 

[timb]

Tim - Andy's formula is right. The problem is that the typical "advertised" hp is a pretty useless number - equivalent to describing speed by saying "this baby will go 150 miles..." and leaving off the "per hour". Now hp at a certain rpm tells you more of the story. In your example that F600 is making that hp at a much lower rpm than your F150 - so the math in Andy's formula works out the torque numbers just fine. Truth be told - provide the same overall gearing (crankshaft to axle) and that F150 will have just as much grunt at the axle as the F600 at those same respective engine rpms used for the advertised. That doesn't mean the F150 driveline components would hold up to that or that while the numbers match at those specific rpms the F600 wouldn't hold it's torque up (rise) better as each engine bogs down under increased load.

Tim

 

[mahlers]

Here's a good description of the Horsepower vs. Torque calculation:

Converting torque to horsepower

 

[gone]

Ok, i'm wrong i did the numbers, the thing is the diesel makes more tourque at the bottom rpms flater curve so the diesel is more powerfull at lower rpms holds hp flater. the gas has a mountain for touque curve, so since tractors run at lower rpms the diesel out does the gas until high rpm.so the diesel makes more power through the rpm range

 

[AndyMA]

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Actually, the Hubble problem was even dumber from what they tell me. They ground the lens here on earth, and didn't properly take into account the distortion that gravity was causing. Once it got into orbit and gravity went away, they realized that everything was screwed up. A Mars mission blew-up because of the unit-conversion thing. )</font>

Yep, you'e right I just got the two of them confused late at night, old age thing you know /forums/images/graemlins/confused.gif

Guys, thanks for helping me out with the torque vrs hp thing, it's always been one of those things where every body has their opinions, not to be confused with fact. You know as engineers how many times you knock heads against old wives tales. The one that reallt gets me is that engineers design things to wear out. Of course we do, everything has to wear out when made to a certain price point. Never once with all the engineers I've worked with and all the products we've designed, have we said, lets get this sucker to wear out / break right out of warranty. We've always tried to give the customer the best value for their money. "cool"

Hey and by the way, the NH TN75,D,S has a 38% torque rise..... Did I just start a torque rise war?

Andy