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  #31  
Old 12-06-2021, 06:08 AM
N82VM N82VM is online now
 
Join Date: May 2017
Location: Warrenton, VA
Posts: 171
Default Drifting

The OP is looking for real world numbers.
Answers to the original question will help someone make an informed decision, including myself.

With the recent 13% increase in engine cost it’s conceivable that may have blown the build budget for many. The previously planned C/S prop is the place to make a big cut.
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  #32  
Old 12-06-2021, 10:52 AM
moespeeds moespeeds is offline
 
Join Date: Apr 2021
Location: Cherry Hill, NJ
Posts: 160
Default

Quote:
Originally Posted by N82VM View Post
The OP is looking for real world numbers.
Answers to the original question will help someone make an informed decision, including myself.

With the recent 13% increase in engine cost it’s conceivable that may have blown the build budget for many. The previously planned C/S prop is the place to make a big cut.
Generally speaking, one of the greatest challenges around here is getting your actual question answered...
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  #33  
Old 12-06-2021, 12:10 PM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is offline
 
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 3,728
Default

Quote:
Originally Posted by moespeeds View Post
Generally speaking, one of the greatest challenges around here is getting your actual question answered...
From memory so don’t hold me to it.
- RV-8A with Sensenich FP prop, 180hp IO-360, 2600 RPM at 4500’, 165 kts. I limited RPM to 2600 so it could go faster if I tolerated the excessive RPM.
- Same RV-8A with Hartzell CS prop, 2500 RPM at 4500’, 175 kts (and about a GPH less fuel burn LOP).

Carl
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  #34  
Old 12-06-2021, 12:30 PM
Rusty1 Rusty1 is offline
 
Join Date: Oct 2021
Location: Woodville,tx
Posts: 3
Default Antisplat east exit bar

AgE 76, RV6A 180/fixed, installed to ease entry/exit of self and wife of same age.
Love it! Significantly easier now.
Easy to install and well engineered product. Planning on more purchases.
Bill Hall
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  #35  
Old 12-07-2021, 05:52 AM
N82VM N82VM is online now
 
Join Date: May 2017
Location: Warrenton, VA
Posts: 171
Default Climb differences

Quote:
Originally Posted by Carl Froehlich View Post
From memory so don’t hold me to it.
- RV-8A with Sensenich FP prop, 180hp IO-360, 2600 RPM at 4500’, 165 kts. I limited RPM to 2600 so it could go faster if I tolerated the excessive RPM.
- Same RV-8A with Hartzell CS prop, 2500 RPM at 4500’, 175 kts (and about a GPH less fuel burn LOP).

Carl
Hi Carl,
Thanks for the numbers. Did you notice a significant difference in climb FPM performance?

For example, loaded near gross and climbing to 8000 to 10,000ft
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  #36  
Old 12-07-2021, 07:44 AM
spatsch spatsch is offline
 
Join Date: Nov 2014
Location: Denison, TX
Posts: 364
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I think there is a whole lot more than just speed to make the prop decision. I have a Cato 3 blade prop and am very happy with it. The speed I am getting is about 5 knots less then what others reported which is probably due to the fact that I don't have wheel pans on (I am going into pretty rough fields and got tired of banging them up) so as you can see speed is really not my main concern.

As for cruise speed. If I do fly cross country I put my throttle on full and leave it there till I start my decent. On the climb up I lean to keep the EGTs constant and when at cruse (which is typically above 7500) I lean to 2700 RPM lean of peak or to highest RPM I can get if I can't reach that. As others said the Cato prop feels really smooth there. Feels better to me then running it at 2400 RPM but maybe that's just because I am so used to it.

Now in terms of cross country advantage in terms of time. As I do the maintenance I take a total time approach to this. If you have somebody else do the work you might look at it differently.

Lately I am only flying 60 hours a year down from about 100. Let's go with 100 hours for this exercise as its more favorable to constant speed props. So if I spend 1 hour of additional maintenance my effective speed (time I spent with the airplane vs distance flown) goes down by about 1%. Most people I know spend at least a couple of hours on extra maintenance on their constant speed prop not counting the days they can't fly at all because of something needing investigating... . So using that math a constant speed prop makes you actually loos time for most of us and reduces the days the airplane is available for flying. Now if you flew really a lot 100s of hours a year and you have a paid for professional maintenance team that math might change but most of us don't.

Don't get me wrong if you want a constant speed prop by all means get one but I am not sure you can make a honest time argument for it.

Oliver
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  #37  
Old 12-07-2021, 08:57 AM
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jneves jneves is offline
 
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Location: Livermore, CA
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Default

I'll be posting some results later this week as I go from the Sensenich 2 blade metal FP to the Catto 3 blade carbon FP. I have been happy with the performance of the Sensenich, but it's a bit heavy and the Catto just looks so sexy. Before I get any comments on why.... I bought the plane with the Sensenich installed and the Catto boxed up for refurb. I sent the Catto to them for refurb and the cost just made sense. I LOVE the way the 3 blade looks, I wouldn't mind shedding some weight and from the folks I have talked to the carbon 3 blade runs so smooth.

If weather permits I'll fly out to Catto tomorrow for the switch or if the fog sticks around, later this week. I'll get performance number on the Sensenich on the way out and the Catto on the return flight. Should be interesting to compare the 2 back to back.
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N455DM - RV-6A - Bought Flying - 2021
Tip Up Canopy
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  #38  
Old 12-07-2021, 09:28 AM
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Carl Froehlich Carl Froehlich is offline
 
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Location: Dogwood Airpark (VA42)
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Quote:
Originally Posted by N82VM View Post
Hi Carl,
Thanks for the numbers. Did you notice a significant difference in climb FPM performance?

For example, loaded near gross and climbing to 8000 to 10,000ft
The short answer, climb after installing the Hartzell BA CS prop was noticeably better than the FP Sensenich prop across all flight conditions. But shoot fire, any RV climbs well regardless of what prop you are using. The prime reason I made the switch was to gain cruise efficiency (as in MPG at ~170kts). This design target drove the engine and prop decision process for the next three RVs as a well. Your mission profile may be different so establish your own design objectives.

The current RV-8 has 260 hours on it over the last 18 months, 90% being cross country. A few long runs have been at gross weight (up to 14K’) and while I could see the weight effect it made no difference in how I operated the plane. I did lose a couple of knots when at gross, but for two 3.5 hour legs back to back up to Denver this was in the grass.

One last comment on considering prop weight. While I’m a firm disciple of Van’s built it light principle, I evaluate total impact when looking for weight reductions. For example a nice, composite FP prop might shave off 20-25 pounds, will the trade offs of to get this reduction improve overall performance or not? W&B is not really an issue as this is part of the “where do I mount stuff” process.

Shoot fire, I would be much better off shaving 20-25 pounds off of me - win/win.

Carl
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  #39  
Old 12-07-2021, 01:17 PM
spatsch spatsch is offline
 
Join Date: Nov 2014
Location: Denison, TX
Posts: 364
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Quote:
Originally Posted by jneves View Post
I'll be posting some results later this week as I go from the Sensenich 2 blade metal FP to the Catto 3 blade carbon FP. I have been happy with the performance of the Sensenich, but it's a bit heavy and the Catto just looks so sexy. Before I get any comments on why.... I bought the plane with the Sensenich installed and the Catto boxed up for refurb. I sent the Catto to them for refurb and the cost just made sense. I LOVE the way the 3 blade looks, I wouldn't mind shedding some weight and from the folks I have talked to the carbon 3 blade runs so smooth.

If weather permits I'll fly out to Catto tomorrow for the switch or if the fog sticks around, later this week. I'll get performance number on the Sensenich on the way out and the Catto on the return flight. Should be interesting to compare the 2 back to back.
Just a reminder switching props will require you to go back to phase 1. (at least with my ops limitations)... .

Oliver
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  #40  
Old 01-02-2022, 08:30 PM
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CESSNA180FL CESSNA180FL is offline
 
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Location: 30 SE of Wichita, KS (SN52)
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O-360A4A w FP Sensenich
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