Electric vs. nitro, watts/horsepower.

[Scoob]

I have a simple question that I've been meaning to ask some knowledgeable people.

1 HP = 746 watts

It seems that an electric doesn't need nearly the peak horsepower of a nitro to have the same or greater performance.

Why is this? Anyone who's competed with nitro, with a BL and knows the nitro HP ratings, understands what I mean. My electric supposedly has 1/4 the power of the nitros but is just as fast.

[pb4ugo]

Originally Posted by Scoob

I have a simple question that I've been meaning to ask some knowledgeable people.

1 HP = 746 watts

It seems that an electric doesn't need nearly the peak horsepower of a nitro to have the same or greater performance.

Why is this? Anyone who's competed with nitro, with a BL and knows the nitro HP ratings, understands what I mean. My electric supposedly has 1/4 the power of the nitros but is just as fast.

Area under the curve.

[Gustav]

Yes,simple as that,for the same peak power as the nitro,the average power across the rev range is higher for an electric motor.

[Scoob]

Oh OK. So it's a powerband thing? What we need in RC is a real wheel dyno to show power at the wheels and graph out a curve. That would be awesome.:003:

[pb4ugo]

I should also bring up how over-rated engines are in our hobby. A reliable standard would help eliminate that, but one marketer would push the envelope with ratings, get a lion's share of the sales, and the market would be back to it's current state. I highly doubt that 20% of the engines actually produce their rated output.

[crazyjr]

Originally Posted by Scoob

I have a simple question that I've been meaning to ask some knowledgeable people.

1 HP = 746 watts

It seems that an electric doesn't need nearly the peak horsepower of a nitro to have the same or greater performance.

Why is this? Anyone who's competed with nitro, with a BL and knows the nitro HP ratings, understands what I mean. My electric supposedly has 1/4 the power of the nitros but is just as fast.

I noticed that as well, i have a Novak hv brushless with 375W, which is roughly .56HP and have no trouble running with the nitro's, must be the torque

[BrianG]

Yeah, it's the same with 1:1 vehicles. Manufacturers only list the peak HP, which is usually at or near the top of the RPM range, which is kinda useless as you don't have much RPM left to take advantage of the power before you have to shift. Torque is almost always rated at its peak as well and is usually only for a narrow RPM range. An electric motor has almost full power at all RPMs which makes it feel much stronger. If you were to average out a Nitro engines' torque or HP over its full revv range, you'd find it is probably less than half its rated value.

[squeeforever]

I have also read on several highly reputably nitro engine manufacturers websites that there is no accurate way to rate a nitro engine...

[pb4ugo]

Accurate is simply referencing a standard. I challenge that there would be if someone established it. Xtremerc is the closest IMO.

Originally Posted by pb4ugo

Accurate is simply referencing a standard. I challenge that there would be if someone established it. Xtremerc is the closest IMO.

yup their dyno readings seem to be the most "down to earth". their highest HP nitro bog block was like 1.89 or something like that...

[coolhandcountry]

Don't they have a mini dyno machine or something?
I read or seen a site some where with real dyno readings on small motors.

[squeeforever]

Coolhand, I think what it is, is that the small dynos are so rare that they don't have a standard as for what the equivilent to 1HP is. Not sure, but thats what I think. So I guess 1HP might be with a certain load on one dyno, while on another, it might be 1.4HP with that same motor. Just a guess though...

[pb4ugo]

Originally Posted by squeeforever

Coolhand, I think what it is, is that the small dynos are so rare that they don't have a standard as for what the equivilent to 1HP is. Not sure, but thats what I think. So I guess 1HP might be with a certain load on one dyno, while on another, it might be 1.4HP with that same motor. Just a guess though...

Close. 1hp is 1hp no matter what. I forget the number off hand, but it's amount of work per time. So is watts. Where the variance comes in is ambient conditions and test methods. An engine w/out an air filter will produce more power than one with. That's where a standard comes in to play similar to SAE standards on real cars. I forget who does the dyno systems for Xtreme (nitrodyne?) but if that became the standard tool and correction factors were developed to "standardize" test conditions then it would be "the standard". Now run it on a different dyno, and true you will get different numbers based on measurement techniques. The engine is producing the same power though.

[crazyjr]

The dyno used by XRC is a nitrodynesystems it uses a real drag to determine real power, instead of a big wheel and reving to create theoretical numbers.

But on that note, HP is just a theoritical number based on rpm and torque based on computer formulas

[pb4ugo]

Nothing theoretical about it (except some manufacturer's claims).
1hp=33000ft.lbs/min

The ability to do work over time.