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Old 12-03-2021, 08:35 PM
Northernliving Northernliving is offline
Join Date: May 2005
Location: Boston, MA
Posts: 671

Originally Posted by moespeeds View Post
For the guys running fixed pitched props with a 360, what kind of cruise speeds and climb rates are you seeing?

Anyone running a 3 blade FP?

Asking for a friend.
Putting a FP prop on a plane with a performance envelope like an RV Is like driving a corvette stuck in 3rd gear. Sort of fun, but you sure are missing a lot.
Brian J.
Boston, MA
RV8 Based at ORH - Purchased
New Superior IO-360-B1AC2 w/Hartzell Composite CS
RV8 - #83313 - Under Construction (sort of!)
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Old 12-03-2021, 10:18 PM
gasman gasman is offline
Join Date: Mar 2007
Location: Sonoma County
Posts: 4,443

Placing a heavy c/s prop on an RV 3, 4, 6, 7, or 8, makes your RV handle like a dump truck.
VAF #897 Warren Moretti
2021 =VAF= Dues PAID
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Old 12-04-2021, 12:17 AM
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Dan 57 Dan 57 is offline
Join Date: Sep 2018
Location: LSZF
Posts: 998

Placing a heavy FP prop, gadgets, or fat pilot/pax on an RV 3, 4, 6, 7, or 8, makes your RV handle like a dump truck.

And cruising at 2600 RPM iso 2300 or 2000 gets you tired quickly, not even touching the single speed efficiency here…
- ain't the Destination, but the Journey -

RV-6.9 #25685, slider, O-360-A3A (carb/dual Lightspeed II), MTV-12-B, HB-YLL owner & lover
RV-4 #2062 HB-YVZ airframe builder
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Old 12-04-2021, 02:11 AM
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rv8ch rv8ch is offline
Join Date: Feb 2005
Location: LSGY
Posts: 4,773

Originally Posted by Dan 57 View Post
Placing a heavy FP prop, gadgets, or fat pilot/pax on an RV 3, 4, 6, 7, or 8, makes your RV handle like a dump truck.
I have never driven a dump truck, but now I want to give it a go, if it's as fun as my RV-8!
Mickey Coggins
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Old 12-04-2021, 04:35 AM
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plehrke plehrke is offline
Join Date: Sep 2006
Location: Defiance, MO
Posts: 1,933

24 posts on this thread and no one has mentioned nose gear vs taildragger and its relation to prop selection.

Choices and opinions are what makes Experimental Aircraft the best Aviation.
RV-6A - flying 1000+ hours
Paid dues yearly since 2007

There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact. —MARK TWAIN
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Old 12-04-2021, 07:54 AM
PilotjohnS PilotjohnS is offline
Join Date: Jan 2016
Location: Southwest
Posts: 2,322
Default Red October

As Sean Connery’s character said, “We all have are reasons”
John S

WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.

Dues paid 2022, worth every penny

RV9A- Status:
98% done, 2% left to go
Structure done (less gear)
Electrical/Panel done
Firewall Forward 95% done
Fiberglass 90%
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Old 12-04-2021, 08:54 AM
brad walton brad walton is offline
Join Date: Jul 2007
Location: Cypress, TX
Posts: 538

I'm not knocking constant speed props. There are some advantages. Like better climb for the first sixty seconds of flight. CS and FP climb the same after about 120 knots. If you need CS to slow down, perhaps your energy management needs some attention. What I object to is the old saw of "stuck in one gear". CS allow you to cruise at a lower rpm. My fixed pitch Catto runs turbine smooth and quite efficiently at all rpm, not tiring at all. I recall a comment in the RVator that switching from FP to CS felt like a broken motor mount. And being 40 lbs lighter allows the full feel of the design to shine through. These planes just feel best when flown light. So if your mission is mainly cross country, you may want CS. If your mission is total performance, you can't go wrong with a well matched FP. As Van's used to say "build it light and keep it simple".
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Old 12-04-2021, 03:35 PM
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Carl Froehlich Carl Froehlich is offline
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 3,728

As someone who started out with a FP prop (RV-8A) and replaced it with a CS prop (Hartzell BA), I can report that putting a FP prop on that plane was the one big mistake I made on that build.

If you want a plane to fly for the $100 hamburger then it makes little difference. If you are looking for efficient cross country, the choice is obvious.

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Old 12-04-2021, 04:18 PM
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WA85 WA85 is offline
Join Date: Apr 2010
Location: Huntsville, AL
Posts: 174

I primed of all my parts with rattle can primer!!!!! and it made no difference in how fast I can do!!!!
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Old 12-05-2021, 06:49 PM
David Z David Z is offline
Join Date: Aug 2010
Location: Thunder Bay Ontario
Posts: 932

Originally Posted by Dan 57 View Post
Placing a heavy FP prop, gadgets, or fat pilot/pax on an RV 3, 4, 6, 7, or 8, makes your RV handle like a dump truck…
Quite curious how the RV 3 handles with a fat pax? I'm sure it would be fine with the weight of a nose gear, a constant speed prop, but no primer.
Empennage Passed Pre-close Inspection
Wings mostly done
Fuselage assembly, it's a riveting job!
Dash 8 day job is financing the RV8
Donation till September 2022
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