RC engine horse power ratings
#1
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Is there a site somewhere where you can compare the HP ratings of different brand 2 and 4 stroke engines? Some companies advertise their HP, but other do not.
tks
tks
#2

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That's because horsepower for RC engines is totally meaningless. Comparing two engines or buying one based on horsepower is a waste of time & money.
Horsepower, given foot-pounds of torque, equals Torque times rpm divided by 5252. The torque curves have a fairly shallow slope so the big driver is rpm. Put on a small prop or a flywheel, lots of nitro and check the rpm. This will result in a lot of horsepower, but is useless for flying a plane with a normal size prop.
Manufacturer's horsepower rating may also be taken with an open exhaust, no muffler. There are no standards.
Horsepower, given foot-pounds of torque, equals Torque times rpm divided by 5252. The torque curves have a fairly shallow slope so the big driver is rpm. Put on a small prop or a flywheel, lots of nitro and check the rpm. This will result in a lot of horsepower, but is useless for flying a plane with a normal size prop.
Manufacturer's horsepower rating may also be taken with an open exhaust, no muffler. There are no standards.
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ORIGINAL: mrbsltz
Is there a site somewhere where you can compare the HP ratings of different brand 2 and 4 stroke engines? Some companies advertise their HP, but other do not.
tks
Is there a site somewhere where you can compare the HP ratings of different brand 2 and 4 stroke engines? Some companies advertise their HP, but other do not.
tks
#4
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As already mentioned, RC company horsepower numbers are not very useful.
To mean anything at all, you'd need very specific info regarding the way the test was done.
You can browse or search the RCU "Tachometer Readings" forum to see what kind of numbers people are getting in the real world.
http://www.rcuniverse.com/forum/forumid_173/tt.htm
If a person really wanted to do the work, all of this data could be loaded to a database.
To mean anything at all, you'd need very specific info regarding the way the test was done.
You can browse or search the RCU "Tachometer Readings" forum to see what kind of numbers people are getting in the real world.
http://www.rcuniverse.com/forum/forumid_173/tt.htm
If a person really wanted to do the work, all of this data could be loaded to a database.
#5
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I think Ed hit several of us between the eyes. I knew of the H.P. ratings, but how better to explain them too.
I know that just because you got a certain year model engine in thought, does not mean it will put out same in any of the follow-up years, for the Mfg'rs tend to get used to making it then sloppy.
I go to the AMA show in Ontario each January. A few of the Mfg'rs there say they are going to let loose with a new version of ____ the coming spring, and alter the whole line to match that. I see the very same dusty glow engines each year, and hear the same promise too.
Oops, time for a whole new model to come out again.
Wm.
I know that just because you got a certain year model engine in thought, does not mean it will put out same in any of the follow-up years, for the Mfg'rs tend to get used to making it then sloppy.
I go to the AMA show in Ontario each January. A few of the Mfg'rs there say they are going to let loose with a new version of ____ the coming spring, and alter the whole line to match that. I see the very same dusty glow engines each year, and hear the same promise too.
Oops, time for a whole new model to come out again.
Wm.
#6

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Companys who are touting HP figures are gleefully living the marketeers phantasy and for those who make their purchasing decisions based on those figures, I have two prime lots on the golf course in Shangrila you are gonna love. Its a place where 15% is never over a buck a gallon and all .46's have 2.5 horsepower.
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mrbsltz, I assume you are asking about HP rating as you are comparing and shopping for engines? As others have mentioned, the HP ratings are pretty much bogus for the reasons listed. The tach readings on RCU are better, but still subject to a lot of factors such as air density, fuel, etc. so read carefully. There are real world differences between engines of similar size, etc., but unless we are talking extremes, most engines put out comparable power for their design and size, i.e. all 2 cycle .40 bushed motors designed for sport use have about the same power, etc. What you may wish to do is ask for engine combos on a specific plane, or better yet, investigate engines used at your local club if you can. Check out how they perform considering the plane style, prop, fuel used, etc. That should give you a good idea if the engine is suitable for your project/planes. - Cheers