percent power

A forum to discuss the installation and maintenance of the O-320, O-360, & O-540 engines and their variants.
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hydroguy2
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percent power

Post by hydroguy2 »

How did I know if I'm running at 75% power? Not sure I trust my Dynon readout as it seems to jump around too easily.

at 6000'DA and 23.7" 2350 rpm 10.5 gph what power am I really putting out? At 11500' 21" 2350 it still shows I'm producing 72%ROP.

just trying to figure out how hard I am running?
Brian
Townsend, MT

Spike
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Post by Spike »

Operations manual that came with the engine?

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hydroguy2
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Post by hydroguy2 »

That would be swell, if I got one. My engine has enough mods that any manual most likely would be wrong but better than nothing I guess.
Brian
Townsend, MT

Spike
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Post by Spike »

Hmmm, that could be of interest. I can think of two ways to go ....

1) Use the manual for the base engine that you have and realize that they are approximate and that the HP numbers will be different.

2) Forget %HP and just use empirical information. During test phase document the engine operation mapping CHT, RPM, FF, MP, KTAS together. Then using the emperical data to create an operating profile that keeps the CHT's in the green. Remember that ultimately heat is the enemy.

Once you have that you can just simply use it as a power chart to determine engine settings for any given flight profile you desire, without worry about %power, which, really, is kind of meaningless.

Spike
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Bob Barrett
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Post by Bob Barrett »

Brian, Do you know anyone that has a portable or tempoary tachometer that you can run to compare the data you are getting from your Dynon?? I think there are some that you might even be able to use in flight. I don't know of anyone that might have one except possibly the FBO at (8Y6). If they have one the cost of coming here to use it would make it cheaper to buy one. Hopefully there is someone around you that will let you use theirs. Good luck!

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hydroguy2
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Location: Townsend, Montana

Post by hydroguy2 »

I have a LED strob-o-scope at work I can steal...borrow. Can't use it while flying because I don't have a long extension cord, but would work to check my tach on the ground run.

I'm not overly concerned about the %pwr reading, EXCEPT right now while running my engine hard. I want to lean things out, but am afraid to burn things up. So I've been running rich and that's not always good either. I see all these numbers and MP/29.9, ect. Well with RamAir I see 21-22" clear up to 11-12000'DA. at 150*ROP I'm burning 10.5gph ome where I'm not sure if my numbers add up correctly.

180kts is not hard to achieve and 170kts True is 8.4gph(LOP). I've had her up to 186kts TAS, but was crapping my pants and didn't snap a picture. :o I still have throttle and rpm left over.
Brian
Townsend, MT

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