VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.


Go Back   VAF Forums > RV Firewall Forward Section > Propellers
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 02-08-2021, 02:52 PM
rcsilvmac rcsilvmac is offline
 
Join Date: Sep 2019
Location: NorCal
Posts: 66
Default Props: From Wood to Catto - initial impressions

I fly an RV-6A with O-320-E2A. I have flown about 150 hours on this plane with a Sterba 68x78 wood prop. I had been contemplating upgrading this prop and had been closely watching threads on this topic but it was really hard for me to get clarity on the impact of this change. Would the plane really be faster, more efficient, dare I say - safer? With all the other maintenance I had been doing the prop just wasn't the top priority.

Lo and behold, a Vans Classified ad popped up with a prop off another RV-6 O-320, and the owner was just a short flight away. Of course who can miss a great excuse to fly, so off I went to "take a look." Of course you know what happened - I got to meet another fantastic Van's RV-6 owner (a regular on this site) and I flew home behind a new (to me) prop.

I thought it would be useful to share an initial PIREP. The prop is a recently refurbished Catto 70" / 70" pitch Glass/Carbon Composite prop. It ended up bolting right onto to my prop extension. After careful ground run ups and a fast taxi, I did a quick pattern, completed another round of ground checks, and flew home. What follows is my first impressions. I am not equipped to do detailed side by side comparisons so I apologize in advance for a subjective review, not an objective one.

First thing I noticed is the throttle control was much more linear. The lighter prop spins up and down quicker. To me this is safety margin, for instance when finely tuning power while on descent. Also adding to safety is that my plane seems to accelerate faster and rotate sooner. Not dramatic, but noticeable in my first couple takeoffs. I definitely think this prop makes my plane more responsive, and hence, potentially safer.

Next item I noticed was this prop was pitched to allow higher RPMs. Static RPM was 2275. In flight on my return trip I was able to hit 2800 rpm in straight and level at 4000' MSL. At that altitude I would only achieve 2600ish with my wood prop. I have a red line on my tach at 2700 and I never worried about hitting it with the wood prop, whereas I was already past it on my first flight home. Of course with the pitch I was also able to hold cruise speed at lower RPMs. This means I now have the choice of greater speed or lower cruise RPM, both nice improvements.

Finally is value. I may be selling this plane in the next year, so value was an important consideration. My Sterba prop has worked well for all the hours on this plane so far (750) and I didn't NEED a new prop. As I considered spending the money I wondered if it would increase the value of my plane to a potential buyer to at least cover the cost of the prop. From a looks standpoint the Catto prop was beautiful (although I need to paint the cowling). The prop change has also made the plane more responsive, faster and/or more efficient. To me, it was worth the investment and any future purchaser would appreciate that I spent the money on the upgrade. What do you think?
Attached Thumbnails
Click image for larger version

Name:	63434652214__79D3EFD2-ACF2-4534-B6F1-7CEE6CD15E2D.jpg
Views:	40
Size:	543.6 KB
ID:	8093  Click image for larger version

Name:	IMG_0116.jpg
Views:	36
Size:	289.0 KB
ID:	8095  Click image for larger version

Name:	IMG_0147.jpg
Views:	39
Size:	232.3 KB
ID:	8097  
__________________
2021 Dues paid
RV-6 with training wheel

Last edited by rcsilvmac : 02-08-2021 at 08:13 PM. Reason: Corrected Static RPM number - was incorrect in original post.
Reply With Quote
  #2  
Old 02-08-2021, 04:42 PM
AX-O's Avatar
AX-O AX-O is offline
 
Join Date: Jun 2005
Location: SoCal
Posts: 2,513
Default

I have done a lot of testing with these props. 2650 static is way too high. 2250-2350 is about where they should hang out depending on the prop requirements.

2650 on the ground is more like 3000 in the air. At least that is what we were seeing at Reno during races.

Glad you are happy. But you may want to do more testing. Something sounds off.
__________________
Axel
RV-4 fastback thread and Pics
VAF 2020 paid VAF 704
The information that I post is just that; information and my own personal experiences. You need to weight out the pros and cons and make up your own mind/decisions. The pictures posted may not show the final stage or configuration. Build at your own risk.
Reply With Quote
  #3  
Old 02-08-2021, 05:18 PM
Kyle Boatright Kyle Boatright is offline
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 4,458
Default

Quote:
Originally Posted by rcsilvmac View Post

Next item I noticed was this prop was pitched to allow higher RPMs. Static RPM was 2650. In flight on my return trip I was able to hit 2800 rpm in straight and level at 4000' MSL. At that altitude I would only achieve 2600ish with my wood prop. I have a red line on my tach at 2700 and I never worried about hitting it with the wood prop, whereas I was already past it on my first flight home. Of course with the pitch I was also able to hold cruise speed at lower RPMs. This means I now have the choice of greater speed or lower cruise RPM, both nice improvements.
I left the paragraph intact for context, but don't understand the bolded statement.
__________________
Kyle Boatright
Marietta, GA
2001 RV-6 N46KB
2019(?) RV-10
Reply With Quote
  #4  
Old 02-08-2021, 06:09 PM
rcsilvmac rcsilvmac is offline
 
Join Date: Sep 2019
Location: NorCal
Posts: 66
Default

Quote:
Originally Posted by Kyle Boatright View Post
I left the paragraph intact for context, but don't understand the bolded statement.
My understanding was the Lycoming O-320 could deliver additional performance at RPMs higher than the 2600 I was seeing on my old prop - hence by being able to drive higher RPMs (to 2700) I can achieve greater performance. I also felt, albeit only after 1 flight, that I was able to maintain ISO IAS at lower RPM, hence gained efficiency.

Does that make sense?
__________________
2021 Dues paid
RV-6 with training wheel

Last edited by rcsilvmac : 02-08-2021 at 06:17 PM.
Reply With Quote
  #5  
Old 02-08-2021, 06:20 PM
Kyle Boatright Kyle Boatright is offline
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 4,458
Default

Quote:
Originally Posted by rcsilvmac View Post
My understanding was the Lycoming O-320 could deliver additional performance at RPMs higher than the 2600 I was seeing on my old prop - hence by being able to drive higher RPMs (to 2700) I can achieve greater performance. I also felt, albeit only after 1 flight, that I was able to maintain ISO IAS at lower RPM, hence gained efficiency.

Does that make sense?
Yes. Thanks for the clarification.
__________________
Kyle Boatright
Marietta, GA
2001 RV-6 N46KB
2019(?) RV-10
Reply With Quote
  #6  
Old 02-08-2021, 07:07 PM
rvbuilder2002's Avatar
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,292
Default

Quote:
Originally Posted by AX-O View Post
I have done a lot of testing with these props. 2650 static is way too high. 2250-2350 is about where they should hang out depending on the prop requirements.

2650 on the ground is more like 3000 in the air. At least that is what we were seeing at Reno during races.

Glad you are happy. But you may want to do more testing. Something sounds off.
I was thinking the same thing.
Either there are errors in some of the info you provided because of typos, or other info is just plain not possible.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #7  
Old 02-08-2021, 08:12 PM
rcsilvmac rcsilvmac is offline
 
Join Date: Sep 2019
Location: NorCal
Posts: 66
Default

Quote:
Originally Posted by rvbuilder2002 View Post
I was thinking the same thing.
Either there are errors in some of the info you provided because of typos, or other info is just plain not possible.
Yes, I put the wrong static number in. I apologize for confusion and have corrected the original post. We actually saw 2275 RPM static.
__________________
2021 Dues paid
RV-6 with training wheel
Reply With Quote
  #8  
Old 02-09-2021, 05:55 AM
BH1166 BH1166 is offline
 
Join Date: Nov 2017
Location: Eatonton Georgia
Posts: 398
Default Enjoy

If you are happy and safe, thatís all that matters I guess. I think you might have a custom built catto to a clients specs Here is what the factory states best in class for your 6A w/ 150hp lycoming engine. Also it is my understanding your prop is wood, covered with composite materials. Have fun !
Attached Thumbnails
Click image for larger version

Name:	4600C166-9AC0-47E1-86BB-A73AEF9F3911.png
Views:	73
Size:	249.1 KB
ID:	8130  
__________________
Butch
RV6A Purchased N72TX
Reply With Quote
  #9  
Old 02-09-2021, 08:49 AM
Wilson Hoffman Wilson Hoffman is offline
 
Join Date: Dec 2007
Location: Oakland, California
Posts: 10
Default

When I took my catto prop in for a pitch change and refurb he changed the torque setting to 35 ft-lbs. You might want to call him.
Also, now I don’t get above 2700 on my o-320.
Wilson Hoffman
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 03:16 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.