montezuma

Hello
I would to know how can i calculate the maximum torqe of an O.S 140 RX engine,and what is the r.p.m of the maximum torqe.
I am using 16*14 apc prop.

rmh

you can NOT calculate torque and the rpm for max torque is also a quantity that won't calculate .
you can guess at it or read manufacturers' figures but unless you are using same exhaust system /fuel/ at same temperature and air density - the numbers are dreck

Scar

My Feedback: (3)

Just out of curiosity..... what would be the point of determining the "torqe" of your engine?

If there is something you want to know, describe with details. Usually, with enough details, we can guess what parameter you actually want to know. Like Thrust, or power, or...

Dave Olson

alfonso8182003

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Kweasel

My Feedback: (29)

You can build a dyno to measure torque, its difficult to accurately predict.

montezuma

HELLO
MY NAME IS BENNY,I AM FLYING RC MODELS FOR 14 YEARS AND NOW I AM MAKING A PROJECT FOR MY PRACTICAL MECHANICAL DEGRE(2 YEARS STUDING FOR BASIC INGENEERING KNOWLOGE)
IN MY PROJET I COMPERING BEETWEN GAS AND GLOW ENGINE. ZENOA 231PU FOR HELI AND O.S 140 RX (BOTH HAVE THE SAME DISPLACMENT 23CC)
I WANT TO SHOW THE DIFRENCE BEETWEN THE 2 KIND OF ENGINES.
I ALSO WANT TO KNOW WHAT ENGINE IS MORE "FLEXIBLE"


MAX TORQE R.P.M AT MAX OUT PUT
ENGINE FLEXIBILITY= ----------------------------- * ------------------------------
TORQE AT MAX OUT PUT R.P.M AT MAX TORQE

IN GAS ENGINE CATALOGE THERE IS GRAGH THAT I CAN TAKE THIS PARMETERS. BUT IN GLOW ENGINE (O.S) I CAN NOT FIND IT.

THANK YOU FOR YOUR HELP

I AM SORRY FOR MY POOR ENGLISH.

Scar

My Feedback: (3)

http://www.rcfaq.com/

You may find enough information there for your purposes.

I doubt you will find power curves published by OS or any other glow engine manufacturer. Sometimes RC Report will do prop comparisons in their engine reviews, but no one I know of goes to the trouble to create power curves.

Good luck with your project.
Dave Olson

rmh

Mike Billington - once wrote engine reviews which included torque and horsepower curves. I think these were published in Model Airplane News - don't remember.
To save you some time - here is some info which may get you started .
the real differences between the engines you note , stem from the fact that one uses a spark ,which allows precise timing of the ignition point and the other uses a catalytic recation of alcohol and platinum to ignite a fuel charge. The timing is variable-based on heat and pressure .
To compare the MECHANICAL aspects of the OS and the Zenoah, is something else again.
One engine was developed as an industrial engine and the other as a very good "toy" for hobby uses.

mrbigg

My Feedback: (21)

the RPM of maximum torque is 5,250. If you look at dyno runs on car engines you will see that this is where maximum torque occurs. It is also where the horsepower figure will be the same as the torque figure. This because when figuring horsepower you use the number 5,250 in the equation.

mmattockx

This is not true. Maximum torque occurs at the point of maximum cylinder filling, which can be anywhere in the rpm range depending on how the engine is tuned. The number is actually 5252 and is the conversion factor for getting between the measured variables (torque and rpm) and the calculated variable (hp), which is why torque and hp curves always cross at this point.


Mark

mrbigg

My Feedback: (21)

Yep, your right about my first part. What I meant to say was that by 5,200 rpm, most engines are on the downside of the torque curve. Even 454 cu.in. big blocks with high duration, high lift cams are losing torque but gaining horsepower past this point. An exception would be a be diesel where they are out of steam by 1,900 rpm.

rmh

how about " max horsepower can not exceed max torque below 5200."
Maximum torque can occur above this number tho
Max torque is the point where max usable pressure occurs in the cylinders
example: my 80 Super will easily turn a 27x10 at 5800- on an open stack
add a tuned pipe - the same prop goes to 6600. This is all a measureable torque increase as the same load is turned faster on the same direct output. Time is not a factor .
Horsepower being an expression of work and time, also goes up.

mmattockx

Careful about that generalization. My GSXR1000 makes peak torque WAY above 5200rpm. No matter how you cut it, that 454 is dinosaur technology and is not necessarily representative of most engines these days. At one time, yes, but not anymore.

To bring this back to aero engines, the G-26 makes peak torque from 8000-9000rpm and the G-62 makes it from 7000-8000rpm. Neither is exactly a small, screamer type of engine (like a .40 pylon engine, for instance)...I use these for examples because Zenoah have actually published the hp and torque curves, which is unusual these days.


Mark

rmh

A local guy has permission to try a speed run on a blocked of straight section of highway 89-
He is flying a Hayabusa with a turbo- and going for ---260 mph - He has already run well over two hundred
I wonder what the max torque is on this monster --

mmattockx

Way too much...


Mark

rcdude7

My Feedback: (264)

I dunno what max torque would be, but the number is huge I'm sure. A stock Hayabusa has about 190HP! For the last six?? years or so japanese bikes have been governed to limit speeds to 186mph. Some kind of gentelmens agreement between the manufactures I think.

My suzuki SV1000S has about 110HP and goes faster than I care to,..........at least on public roads

mrbigg

My Feedback: (21)

here's a link to a dyno run. http://photos.motorcycle-usa.com/hay_zx14torq.jpg
http://photos.motorcycle-usa.com/hay_zx14hp.jpg

rmh

It takes 4 x the power to double the speed - discounting drag-
I have a video of a busa cracking 235 -
another shot of one with twin turbos - claimed to crank---500 hp---

Kweasel

My Feedback: (29)

There's nothing like being able to lift the front tire at 150. Well, a hydrogen peroxide rocket sled may be more thrilling.

adamiani

My Feedback: (2)

How can I find where to buy a Torch 40. Thks

Jburry

Horsepower = RPM x Torque / 5252

Torque in foot pounds.

From ThrustHP, useful software for working with model aircraft props:

Load = Prop Diameter^4 * Pitch
Horse Power = Load * rpm^3 / 1.4 * 10^17
Static Thrust = 0.00000000000283 * rpm^2 * Prop Diameter^4 * Air Density/29.92 * CF value

Units in inches for pitch and diameter. Air density in inHg

All of this should be considered fairly approximate, but if you're looking to quantify horsepower vs rpm vs torque, this is useful.

Hope this helps!

J