0-200 gallons per hour....

[6597]

Do you typically fly .........say above 7000 feet?

I just did a flight to the coast a few weeks ago, 3-5000', whale watching, regular leaning got 5gph. 2500 rpm. 100-105 indicated. Mostly a mogas blend these days. REM37BY's for plugs. Milleniums with say maybe 250 hours on them.

I don't usually fly too high unless I have some hills/mountains to get over. I'm more in the 3000' agl range.

Is yours a 46 or later? I put an O-200 in my 47 and struggled with oil temps ever since.

Mine's an early 46' with the lower cowl 'lower'. I struggle with CHT's rather than oil temp. The FBO IA said to try and put a sheet of metal across the bottom cut-out to see if it could draw more air thru the top. Results are so-so. I have new side baffles cut out but haven't bent them to fit yet, in an effort to seal up every last little crevice on the sides.

I think Josh may have a point in that the shallow 42" pitch just doesn't really put a lot of strain on the engine in cruise?

[6643]

the shallow 42" pitch...

That's beyond shallow! What is the prop length? What is your static RPM?

Standard prop for a C150 is 69x50, so 69x46 would be extreme climb.

I forget, but, did you post the manifold pressure at cruise? Manifold pressure is a direct indicator of power output for a given RPM. Unfortunately, I've never seen a power chart for an O-200 that relates MP to power.

[6597]

That's beyond shallow! What is the prop length? What is your static RPM?

Here ya go....from a distant past owner. I am guessing he had a 71" prop from his old C85 installation and wanted to use it for the 0-200 installation. Static right at 2400.

img220.jpg (122.43 KiB) Viewed 849 times

I forget, but, did you post the manifold pressure at cruise?

Yup, scroll back a few. Generally 21-23 inches give or take. RPMs generally 2450-2500. I wish I did have the power charf/MP for the 0-200. My guess is it's not working too hard. I know that climb props lose in cruise speed a little versus cruise props losing in climb a lot, at least as a general rule of thumb.

[6643]

Well, bottom line is I expect you're driving around in second gear... Can you exceed red line in level flight?

[6597]

Can you exceed red line in level flight?

Yup. Previous owner I think was all about climb performance. Maybe he was trying for the back country thing or considering floats?. I throttle back by instinct when I level from climb out.

Prop History-
7-22-82 overhaul CM71/45 1B90
9-15-82 installed on C85
6-26-84 re-pitch from 45 to 48"
1-25-88 re-pitch unknown spec
9-5-90 re-pitch to 42'
3-14-05 overhaul, 2 stations out of spec, kept 42"

I like your second gear analogy. I did check the airspeed indicator and against the GPS and I'm pretty much in the 100-105/110 range.

Next prop overhaul if I live that long will consider 44"

[6643]

Next prop overhaul if I live that long will consider 44"

There are rules about how many times you can repitch it, and how many changes of direction are permitted. It's already gone from 45-48-X-42 (that we know of). Are there a lot of numbers stamped on the hub?

[6597]

I think I'll check the serial number. I'll also look at the old prop logs for that unknown pitch. I only see a 44 to 42 change here.

IMG_20160519_200733048.jpg (106.91 KiB) Viewed 788 times

[V529]

Hmmmmm, very interesting info..........I'll bet your prop has something to do with it. I don't recall seeing/hearing of that prop on an O-200.......

[6597]

I don't recall seeing/hearing of that prop on an O-200.......

It's on this doc...

P-842PropTypeCertificate.pdf

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[6643]

It's on this doc...

It's approved (tested) by McCauley, but I don't know of any plane that was originally certified with one on an O-200.