xism

I just wondering... 2-3 hp för those small nitro motors. but is hp really about torque?

i strongly doubt a GS21 engine for example has more torque than a 12 volt 700 size motor ie.
how much torque does a .21 engine have? (in m-Nm)

Nitro Fumes

One thing about electric motors, they can apply torque at ZERO RPM, so can steam engines. But internal combustion engines, like our little Nitro engines cannot put out torque at ZERO RPM. But they can put out gobs of it when running. It just depends on the design. A longer stoke engine will put out more torque than a shorter stroke engine, but the shorter stroke engine can rev to a higher RPM.

ryan_t888

For example the weakest OS .21 engine has 1.9hp @ 30 000RPM http://www2.towerhobbies.com/cgi-bin...?&I=LXBZ32&P=7

Using a simple torque/horsepower equation it makes .451 newton metres of torque.

Remember low end torque on a nitro engine depends on when the clutch engages. A later engagement multiplies the engine torque.
Also on a nitro engine the torque curve has a peak and drops off at both ends. An electric makes peak torque at its stall point and has a linear torque curve.

Ryan

xism

ok, interesting,.. kershaw make those conversion kits which gonna make the car goes faster than it does with the nitro engine

ryan_t888

Would you happen to know the amount of torque a 700 series motor has? I can't find any specs.

Ryan

xism

you can find facts here
look at the 8514(ton's of torque!): http://www.mabuchi-motor.co.jp/cgi-b..._ID=rs_775vcwc

and what about this one [X(] ?!: http://www.johnsonelectric.com/produ...p?ProdID=82--A

ryan_t888

mNm stands for milli Newton Metre right? If so the OS in the above post produces 451 mNm of torque. Thats 3x more than the 8514

Ryan

xism

no way it cant be,... 3x more torque than a 775 motor? impossible. u maybe got it wrong?
horsepower has nothing to do with torque/power

ryan_t888

Actually horsepower has a direct relationship with torque. It is related to the amount of horsepower produced at a certain RPM. If max power is produced at a larger RPM, (greater than 5252) torque will be smaller. If horsepower is small at an RPM (lower than 5252), torque will be greater than hp.

Try it = --> (Torque x Engine speed) / 5,252 = Horsepower (Units are pound feet for torque, hp for horsepower and RPM for revs/min)

Ryan

xism

the only way to measure hp(who is all about kw per hour) goes in a matematical form. the only way to measure torque on the other hand, is right on the motor axle. so, u can never measure hp on a axle ... couse hp isnt about power. "hp" is only about working capacy per hour right?

so to proof that hp isnt about torque, we can take this example:

a rc car engine at 3 hp
a 50cc scooter at 1 hp

still the scooter is build to transport a human... but has 3 times less power? (if we take your example: hp = torque)

i belivs its about two total different things

ryan_t888

LMAO.. you just proved my point here:
The RC car makes this power at over 30 000RPM, much over the 5252RPM in the equation. The 50cc scooter makes this power at around 8000RPM Only slightly over 5252 compared with 30000.

Therefore the amount of torque in your example for the scooter would be 890 m-Nm.

Once again horsepower has a direct relationship with torque. It is not two totally different things!!!!!!!!

Instead of me trying to explain it,(thought it was quite clear in my previous post) look here for yourself! http://auto.howstuffworks.com/question622.htm

BTW: where did I say Horsepower=Torque??

Ryan

xism

u did say "horsepower has a direct relationship with torque" ...so what to belive? [:'(]
interesting site.... but i still dont get it [&:]

jkulhanek

Are you on drugs son?

Horsepower is a direct measurement of power. Torquex RPM (forgot the equation now...) = Power

Your electric motors could not hope to outpower a nitro engine, but have very good torque from 0RPM which is their biggest assett.

ryan_t888

You don't need to understand it. Just take the correct numbers with the correct units and place them in to the equation I have provided.

I own a series 700 motor and run it on 16 cells. They don't have as much torque as you may think. But as you get to the 800-900 series, they have a large amount of torque when on 24+ cells.

Ryan

xism

jkulhanek, dont think so... "hp" is a selling trick. it has absolutely nothing to do with torque

a 16 liters truck engine is only about 4-500 hp.
a F1 car has like almost 1000 hp

still the truck engine is much more powerful. how come?
would the f1 motor be able to make a 60-70 tons 18-wheeler to run at 60mph? dont think so!

ryan_t888

DUDE! Plug the numbers in to the equation!! I don't know how many times I have to tell you that torque is derived from horsepower by using simple physics.

I'll once again tell you how much torque each engine has according to your examples. The F1 makes peak hp(1000) @ 16 000RPM The diesel makes peak hp(i'll take 500) at 2800RPM HUGE DIFFERENCE!

Diesel 18 wheeler: 938 foot pounds according to your example

F1: 328 Foot pounds according to your example

Everytime you post an example you just prove my point how hp has a direct relationship with torque. What you are not doing is providing the RPM that the specific engine turns at to make peak hp.

Humans make 1/3hp but at a much slower RPM, why can we move a bike @ 60km/h? Reason is we have tons of torque compared with horsepower. If we make 1/3 hp @ 300RPM(pedal revs) we have 5.8 foot pounds of torque. Makes total sense, this equation can be used for anything.

Remember the torque calculated is at the RPM which max hp is made.

Ryan

Roscco

Horsepower determines how fast you hit the wall, torque determines how much of the wall goes with you after you hit it

xism

ok ryan! iam trying to understand this now! but isnt easy couse iam swedish. and iam not that good to either read or write in english language

ryan_t888

Funny, but momentum is what determines how much of the wall is carried since most people let off the throttle before they hit. Momentum is the product of mass and speed.

About time jk

Ryan

jkulhanek

Do a bit more research...

xism

jkulhanek what to research about? i was telling the truth

and i still belives electric motors have much higher torque then nitro engines.
a t-maxx wouldnt stand a chans against a e-maxx in a tug of war

ryan_t888

In your first post you asked how much torque a .21 engine has. I answered your question and we both found out the nitro engine has 3X more torque than the electric at top speed. Now if the electric is going to be run around it's stall point it has more torque but this is usesless for what you want.

In post 4 you said the electric will go faster than the nitro, just try it and tell me what nitro engine is going back in. As I said earlier I own a 700 series and run it on 16 cells in a boat. It does have more torque than a .12 cu in engine (2.1cc) and can spin a larger prop but when I had a .12 in this boat it was much faster.

You can believe anything you want but facts don't lie. I thought you said you understood now? What are you doing?

T-maxx --> small block .15 operating no where near 30 000 RPM in a Tug!

E-Maxx --> 2 (Two) (Dual) electric motors operating near stall current in a Tug.

Ryan

xism

But it doesnt seems to be logic!! i mean.... a 700 motor at 16 cells(19,2volt!) do only have little more torque then a small .12 engine.
ok you're the expert here and i doesnt even have a 700 size motor. but like i said, it doesnt seems to be logic ... those giant 700 20v motors can spin a prop where a .21 engine even cant move 1 inch.
and yes i said some elctric will go faster.... so dont blame me for kershaw making those conversion kits... ;-)

ok pal facts dont lie, pulling competition between t- and e-maxx is all about torque. and so much truth we can come. if the engine doesnt do 30 000 rpm so what? no excuses here [:'(]

engine geek

Everything Ryan has said is true and makes perfect sense. You say that the 700 series is faster than a .21. hahaha buddy, no way. I just checked Ryan's calculations and they are right on. 3X more torque @ top speed.

Different amounts of torque are produced at different RPM's So the electric can out pull the nitro at very small RPM's. But this is useless when you want more speed as nitros make gobbs of torque at racing speeds not itty bitty 2mph speeds.

The T-Maxx doesn't even use a .21, it uses a small block .15. Small blocks don't make any torque but produce lots of RPM. Also the T-Maxx uses two motors. Maybe we should use 2 nitros to make it comparable.

When you use the kershaw convo kit, tell us how much speed was lost.

I have one question for the science guy.(Ryan) How much horsepower is produced by an electric at it's stall speed. (Just an instantaneous speed)

SManMTB

If by stall speed you mean 0 rpm the answer is 0 hp. It still produces torque but it's not turning and doing any work. Horsepower is a measurement of 'work' ---> No work done = 0 hp.