Flex-o-Fold Folding Prop

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Clay Greene

Hi all - considering moving from my fixed three-blade prop on my 1989 C34 (M25XP) engine to a Flex-o-Fold.  Any thoughts on two-blade versus three-blade and a pitch of 9 versus 10?  The recommendation from the sales representative was either a two-blade with a 10 pitch or a three-blade with a 9 pitch.  I need to question him further on why the pitch difference between 9 and 10.

I want to improve speed under sail, of course, but I don't want to compromise motoring performance.  We cruise and as often as not we end up motoring or motor sailing to get across Lake Michigan before nightfall.  The two-blade is significantly less expensive so if the difference between the two is marginal I would probably go with cost as the deciding factor. 

Thanks for any input or experiences you wish to share. 
1989, Hull #873, "Serendipity," M25XP, Milwaukee, Wisconsin

Wayne

I have no idea the difference is between the two and the three, but I have a three blade and it works really well.  If I push my rpms I can motor right at hull speed (fairly flat water), reverse is fine (as usual way less efficient than in forward) with a modest amount of prop walk--just about the right amount of prop walk to be useful.  I know that a standard two blade has way too much prop walk; I suspect that might be the difference between 2 or 3 blades.
2006 MKII Hull # 1762
San Francisco, Ca

sail4dale

I changed from a three blade fixed prop with 9 pitch to a three blade Flexofold
10 pitch.  I love it (Engine M35B)

I cruise at 6.5-7 knots ad will get it up to 7.5 at times with a clean bottom.
The only difference is that I can not get full RPM because of the 10 pitch.

My full speed is about 2600 RPM without smoke.  However this does give me the speed.
noted above. and a fuel consumption of +/- 0.8 GPH.  (And definitely more sailing speed. .5 kn +)
It is absolutely great in reverse.

I am quite happy with the prop and the service from them when needed; a special zinc that I have not found  available at other than Flexofold.

If you feel that you need full 3000 RPM then I would advise getting the 9 pitch.
.
Cat34 Mk II True Luff #1582  2001
San Pedro, CA (Port of Los Angeles)

Stu Jackson

Quote from: claygr on April 10, 2010, 08:05:49 AMThanks for any input or experiences you wish to share. 

Clay,

I don't recall detailed discussion on your question in all the Flex prop topics.  You might have already done a search on that topic, since there's been quite a lot of discussions about props other than what I lovingly think about as "that bucket I'm always dragging behind us!" 

You might also want to add your "signature" so we know what boat, year and engine you have, in order to help you better in the future.  See:  http://c34.org/bbs/index.php/topic,1506.0.html
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Clay Greene

Thanks for the heads up, Stu.  Think I've made the change.  We'll see when this posts. 
1989, Hull #873, "Serendipity," M25XP, Milwaukee, Wisconsin

Ed Shankle

Clay,
I added a Flex-Fold last year. Went from a fixed 3 blade, both at 10 pitch. I've been very happy with it, picked up speed under both sail and power.

Ed
Ed Shankle
Tail Wind #866 1989 m25xp
Salem, MA

kurt

Clay,

Added a Flex-O-Fold 3 blade folder a couple years back and have been pleased with it.  I selected the 10 inch pitch based upon FoF recommendation for the M25xp.  Regarding 9 or 10 inch pitch you can see my results at the link below:

http://c34.org/bbs/index.php/topic,4298.msg25546.html#msg25546


Kurt

Analgesic

For what it's worth, I recall an artical in Catalina Mainsheet a few years ago describing the performance of the Kiwiprop feathering 3 blade.  At that time it was significantly less expensive than every alternative I considered.  I have now had it for 3 seasons and can verify what the article claimed-0.5 knot increase in sailing speed, fine motoring and powerful thrust in reverse.  You might want to look at this before you buy.
Brian McPhillips
Brian McPhillips  1988 #584  M25XP

Steve S.

Put the flex o fold in about 4 - 5 years ago.  Can't agree more with the posts here.  Better sailing speed and the best benefit was less prop walk in reverse.
Steve S.
Hull 548
Kuching Ayer
Chesapeake Bay

Clay Greene

I checked and my current prop is a 15 x 10.  It is interesting looking through some of these older posts the Flexofold used to recommend a 10 pitch for the M25XP engine and now is recommending a 9 pitch.  Can anyone explain what difference the change in pitch would make other than requiring more RPMs to achieve the same forward velocity?  Or am I worrying about something insignificant? 

Thanks for your help.  This is a decision I really would like to make just once. 
1989, Hull #873, "Serendipity," M25XP, Milwaukee, Wisconsin

Clay Greene

Ed, did the Flex-o-Fold vendor recommend the 10 pitch to you?  He seems to have done so for Kurt (and others in posts I have seen) so I am left to wonder why he is recommending a 9 inch pitch to me.  Perhaps the prop blades were redesigned?  I guess I need to have another conversation with him. 
1989, Hull #873, "Serendipity," M25XP, Milwaukee, Wisconsin

Rick Allen

Speaking of props (sorry for high-jacking), my fixed 3 blade is a 15x9 with a big "10" stamped over the top.  Do you think the pitch has been changed?

Rick Allen, C34 IA Commodore
Former owner of "PainKiller", 1988 C34 MKI, Sail#746, std. rig, wing keel.

Clay Greene

I am a relative newcomer to this whole prop thing, but I don't think you can change the pitch of a fixed prop.  The pitch describes the angle of the blades to the boss of the prop.  You can't change that angle on a fixed or folding prop.  You can adjust the pitch on some feathering props.  No idea why they would have stamped a new number over the old one. 
1989, Hull #873, "Serendipity," M25XP, Milwaukee, Wisconsin

Ted Pounds

I believe you can alter the pitch of a fixed prop slightly (not a lot).  There are companies that do that as part of truing and balancing.  Not sure if you can go a full inch but it seems likely.
Ted Pounds
"Molly Rose"
1987 #447

Ed Shankle

Clay,
Yes, a fixed prop can be adjusted. Had my fixed altered from a 9 to a 10 at a prop shop, based on advice from the Forum. Your Flex supposedly can also be adjusted in the water if you find the 10 doesn't work for some reason. Course I don't know the degree of difficulty....

Ed
Ed Shankle
Tail Wind #866 1989 m25xp
Salem, MA