Replies to This Discussion

Permalink Reply by William C Cooper II on January 31, 2018 at 10:44am

I think prop pitch would be a useful field in your spreadsheet.  Thanks!

 - Bill

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Permalink Reply by John M Greiner on January 31, 2018 at 12:26pm

I am going to show my ignorance here...

1. What would be the best metric and range for this. ie Degrees of Pitch?
2. Whats a normal range for our aircraft typically between cruze pitch and climb pitch?

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Permalink Reply by William C Cooper II on January 31, 2018 at 1:39pm

Many (most?) of the folks building a Zenith seem to choose fixed pitch/ground adjustable propellers because fixed-pitch props are simple and low cost. (That's my impression and I am willing to be wrong.)  For those who want to squeeze more performance out of their aircraft (either in cruise or in climb), an adjustable-pitch propeller is certainly an option that appeals to some.

My brother and I went with a Whirlwind propeller (ground adjustable pitch) because our engine manufacturer recommended it.  Six flights into our tests, we are adjusting the pitch to take less of a bite and increase engine revolutions at full throttle closer to what Jan at Viking recommends.  (Viking is also recommending Duc props now.)

For us fixed pitch prop fliers, knowing where others are setting their props (degrees of pitch), particularly those with the same engine, would be helpful!  I imagine the same would be true for the folks with adjustable pitch props.

Thanks!

 - Bill

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Permalink Reply by John M Greiner on January 31, 2018 at 2:29pm

Bill,
What is a good range of pitch to allow in the field "Prop Pitch" 10 deg to 20 deg ?

I just don't know what the typical ranges are, because in my build, I don't even have an engine to mount a prop to yet. i.e. I don't need to worry about prop pitches yet.

Thanks for any clarification you can provide. Great idea, and I agree. Prop pitch is brought up a lot, and would be nice to see real world info on people flying, which is the primary purpose of the spreadsheet.

John

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Permalink Reply by William C Cooper II on February 1, 2018 at 6:38am

I'll let others speak to their engine/prop combinations, but 15.5-23 degrees is what I have seen for Viking and three bladed Whirlwhinds.  In our own experience, we have been moving our propeller "bite" down a bit after the last two test flights. We are now set at 16 degrees and waiting for improved weather and work schedules to coincide...

Thanks for putting the spreadsheet together...  it sure beats trolling the various sites to gather this info for ideas and comparison!

 - Bill

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Permalink Reply by John M Greiner on February 1, 2018 at 6:49am

Thanks Bill, for both the feedback and the data. You nailed it, in my opinion, the 2 best things that come out of this.

1. one stop shopping, so to speak, for information.
2. You can narrow down who you need to bug / friend with questions.

The airframe choice is not to hard, its driven by your mission mostly.

But the Engine and what Avionics are best for you can be really be tough.

John G.

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Permalink Reply by David Josephson on February 5, 2018 at 1:06am

John, thanks for the spreadsheet. We *can* move into the early 21st century to share info!

Angle between blade chord and prop disk at 75% of radius is about as standard as it gets, the performance will vary depending on prop twist. Maybe more useful would be to list the rpm achieved with the chosen prop pitch, wide open throttle, sea level, standard day, at rotation. Fixed pitch propellers will use pitch stated in inches, see http://zoomaviation.com/programs/prop_angle/

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Permalink Reply by John M Greiner on February 1, 2018 at 1:21am

Here is some fun info of what we have collected so far together.

Don't let your favorite Engine and Kit fall to far behind now...

Just kidding, its not a competition, don't make up numbers to make your plane beat everyone else...

In all seriousness, please be as accurate as you can be, people like myself will probably use this info to make decisions about their own aircraft. In my opinion, nothing is better than hearing from a fellow pilot or builder with real world experiences. No offense to the various suppliers of various aircraft components out there...

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Permalink Reply by RJ Ress on February 1, 2018 at 6:53am

Hey John. Nice spreadsheet.  Thanks for spearheading this.  It will be of value to all of us. Just a quick note, that in your "Zenith Model Choices" you have the CH650B listed twice, Should one of the listing actually be for the CH750 CRUZER?

Rudy

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Permalink Reply by John M Greiner on February 1, 2018 at 7:09am

Thanks Rudy, your right. Oops... No offence to my fellow Cruzers! Spreadsheet corrected and here is the new pic. As long as the STOLs are still winning, I am fine with the correction. Insert smiley face here...

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Permalink Reply by John M Greiner on February 1, 2018 at 6:59am

Minor Update - Fields Added:

• Adjustable Prop - options "Fixed,Ground-Bolts,Ground-Quick,In-Flight Hydraulic,InFlight Electric, Inflight Manual.
• Comments - You can used this to make suggestions, or comments to others, I will be looking at these, but feel free to leave other messages here to.

Up to 30 Planes now.

John G.

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Permalink Reply by Jim Derickson on February 10, 2018 at 8:21am

Hi John, You might consider logging airframe TT?  

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