Engine Horsepower
06-13-2002 | 04:05 AM
#1
Thread Starter
Senior Member
Joined: Jun 2002
Posts: 183
Likes: 0
Received 0 Likes
on
0 Posts
From: AL
Engine Horsepower
From the sites on engiens we get information for the following :
1. Horse Power i.e. 1.9 BHP at 16000 RPM
2. Practical RPM - 2000 to 16000.
To calculate Torque , which RPM do we tke .
Is it better to have a higher torque to choose between engines .
1. Horse Power i.e. 1.9 BHP at 16000 RPM
2. Practical RPM - 2000 to 16000.
To calculate Torque , which RPM do we tke .
Is it better to have a higher torque to choose between engines .
06-13-2002 | 05:56 AM
#2
My Feedback: (16)
Engine Horsepower
If you are good at math... the formula is HP=Torque X RPM/5252.
You should use a prop that lets the engine run about have way between the maximum torque rpm and the max hp rpm.
In your example, you would only be able to calculate the toque at 16000 rpm.
In spite of what the trumped up manufactures figures say, This engine would be happier to turn around a maximum wide open throttle speed of 12000 on the ground.
I would be willing to bet that the engine would not make it to 16000 with any kind of prop on it. That was probably with just a flywheel on it with an electric fan to keep the motor cool?
Look at www.rcfaq.com and see what rpms different engines turned with which props.
enjoy,
Jim
You should use a prop that lets the engine run about have way between the maximum torque rpm and the max hp rpm.
In your example, you would only be able to calculate the toque at 16000 rpm.
In spite of what the trumped up manufactures figures say, This engine would be happier to turn around a maximum wide open throttle speed of 12000 on the ground.
I would be willing to bet that the engine would not make it to 16000 with any kind of prop on it. That was probably with just a flywheel on it with an electric fan to keep the motor cool?
Look at www.rcfaq.com and see what rpms different engines turned with which props.
enjoy,
Jim
06-13-2002 | 12:42 PM
#3
Senior Member
Joined: Dec 2001
Posts: 1,125
Likes: 0
Received 0 Likes
on
0 Posts
From: Adelaide, South Australia
Engine Horsepower
If the information was available then choosing an engine by torque is preferable to choosing by HP. Almost all engines develop max HP at unrealistic revs for normal sport flying.
But I must say that w8ye would lose his bet by a big margin
Put a small enough prop on any engine and it'll breeze in 16K. I'd guess maybe an 8x4 on an LA40 would do the trick let alone on something like a Rossi. As for flat out with a flywheel...well that really depends on what's the weakest point in the engine. If it doesn't break then the revs are only limited by the (reducing) torque available to overcome friction. Ever had, or heard, a shaft run? Wowie!
But I must say that w8ye would lose his bet by a big margin
Put a small enough prop on any engine and it'll breeze in 16K. I'd guess maybe an 8x4 on an LA40 would do the trick let alone on something like a Rossi. As for flat out with a flywheel...well that really depends on what's the weakest point in the engine. If it doesn't break then the revs are only limited by the (reducing) torque available to overcome friction. Ever had, or heard, a shaft run? Wowie!
06-13-2002 | 02:58 PM
#4
Senior Member
My Feedback: (16)
Joined: Apr 2002
Posts: 12,942
Likes: 0
Received 0 Likes
on
0 Posts
From: Locust Grove,
GA
Engine Horsepower
On of the thing you have to remember is that you will get more engine speed in the air than you do on the ground. An engine may not reach 16K on the ground but may do so in the air!
06-15-2002 | 04:51 AM
#5
Member
Joined: May 2002
Posts: 71
Likes: 0
Received 0 Likes
on
0 Posts
From: Collierville, TN
Engine Horsepower
You guys ever wonder why John Deere, Murray and Hoover advertise HP or Amps. It sells!
Does anyone really think that the Japanese, Taiwanese, Chinese, Europeans and US Horse Power standards are really the same. They are probably converted on paper from an electrical load.
I'll bet, and I have built many load cells, that all the power ratings you see are converted from an electrical load applied while testing for Horse Power propoganda! And these loads are not a unified standard.
Remember...there is no replacement for Cubic Inches. Not even ink printed on a brochure.
If it flies and you like it, buy another one. If you don't, try something your buddy likes.
_________________
DoubleD
Does anyone really think that the Japanese, Taiwanese, Chinese, Europeans and US Horse Power standards are really the same. They are probably converted on paper from an electrical load.
I'll bet, and I have built many load cells, that all the power ratings you see are converted from an electrical load applied while testing for Horse Power propoganda! And these loads are not a unified standard.
Remember...there is no replacement for Cubic Inches. Not even ink printed on a brochure.
If it flies and you like it, buy another one. If you don't, try something your buddy likes.
_________________
DoubleD
