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Seasonal Prop Pitch Adjustment
I live in Northern California and fly every other weekend to a high density altitude airport (frequently 6K to 7K density altitude during the summer). It's about a 170 mile trip.
I fly a 601 with an O-235-C1 and a 3 blade Warp Drive prop.
During the summer I really need the prop adjusted for a good climb rate - and get about 1000-1100 fpm solo on a cool day, and maybe 700 fpm on a high DA day.
I have found by trial and error that a 11-1/2 degree pitch gives me the climb I need and still get a decent cruise (approx. 115mph IAS at 2650 RPM (max. 2800)).
My "cruise" setting is 11 degrees (yes, just 1/2 degree difference). Since the cool fall weather is here, today I re-pitched my prop to 11 degrees. It took about 45 minutes start to finish.
I made a short test flight afterwards and was seeing 125 mph indicated at 2650 rpm. Right about a 10 mph difference over my morning with the new 11-1/2 deg. pitch. My climb rate was around 750 fpm.
It's interesting how you can feel the difference in the plane at 10 mph faster - and it feels good!
I will leave the pitch at the cruise setting until next fall when the weather warms up.
I was wondering if others make seasonal pitch adjustments like this? It seems that it's one of the benefits of having the adjustable pitch prop.
Pics are from my flight this afternoon.
Gary
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Replies to This Discussion
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Permalink Reply by Gil DeVault on
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I think I have the same set up as you, 0-235 and three blade adjustable prop. I have no idea how to adjust the prop!
Right now I'm getting all my paperwork done, aircraft annual and BFR, but low ceilings and rain are making it almost impossible to get this all done in time to view the Ozarks Autumn Foliage before all the leaves have fallen. One quick question, in level flight with your 601 do you have a slight nose high in level flight ? When I flew the 650 last week we only had a 700' ceiling and not much of a reference, and the plane had the EFIS which I knew nothing about. It seemed to me the nose was just a little above the horizon in level flight and Rodger told me with my 0235 mine would most likely look the same way.
gil
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Permalink Reply by John M Greiner on
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Replying to WT comment question...
I am going with Viking 130 on a STOL 750 so I will work with Jan and other builders to to get my STOL pitch figured out, which means even slower top speeds or cruise, but awesome climb rates. So prop pitch is fairly straight forward, from what I understand. Lower pitch, allows the engine to spin faster, more torque produced, so the prop will maintain a more constant RPM, so at high pitch it can keep pulling you out at high AOA, like throwing your pickup into low gear and full power to pull you through the mud. Cost being, a high speed prop at low pitch eventually gets more in the way as you speed up in the air stream, just like your truck, you can't get going down the interstate highway in first gear very fast. Now the opposite is true with higher pitch, bigger bites of air. Does better at higher speeds because it cuts the air more efficiently or in sync with your speed as it cuts, or cork screws through the air. I hope I can use a pitch somewhere in the middle, and use the extra 30 HP to create enough torque to maintain prop RPM at high AOA. If this description is wrong or too basic, I apologize, but its the logic I plan to use when adjusting my prop pitch.
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Permalink Reply by David Krakowsky on
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Hi Gary,
I also have a warp drive three blade also, but on a continental o-200
Are you sure you didn’t flip the numbers?
When the pitch goes down, a flatter prop, usually the top speed goes down and the rpms go up, climb rate increases.
I am in flat, hot Florida and also run between 10 and 11 degrees, right know I think I gave it set to 10.5
Top end on my plane is only about 110 at 2650, but I am only running 100 hp on a good day.
Dave
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Permalink Reply by Joe Hopwood on
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I thought the same thing Dave, but did not want to expose my ignorance if I was wrong. :-)
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