Volvo Penta F6 Prop specs

[ramairta1]

Does anyone know what the pitch is on the Volvo DPS- F6 props? I know they are progressive edge props..
Are they matched pitch from and rear props or different. I have searched everywhere and found very little. Someone said they were around a 24 pitch on both???

I am kicking myself now as I took my props to a local prop shop to have they cleaned up- VERY minor cosmetic dings etc.
The shop didn't know much about volvo dp's. The guy who worked my props tweaked them and now I have lost a decent amount of performance (around 3+mph).
I was turning 4700-4750 WOT RPM at 52mph-- Now I am turning 4850-4900 WOT RPM at 48 mph all other factors being equal. Throughout the band it feels a little different. It's a Volvo 5.7 Gxi 320 HP motor- operating range is 4600-5000.

They look great but just don't perform like they did. He has offered to tweak them for free, but he has nothing to go off, to try and get them back where they were. Trial and error I guess.

Anyone know anything about the specs on an F6 set?? any info would be helpful as a starting point.....

Thanks in advance

Still kicking myself....

 

[Maclin]

Re: Volvo Penta F6 Prop specs

I think you know what needs to happen next

In my opinion the prop shop person needs to contact another shop that has the Volvo DP blocks or forms, can't remember what exactly they are called, that knows how to use them and work VP dp's to spec. Your props need to be reformed and he needs to learn what they do to fix them.

The Volvo DP's are a set, they net out to a measurable pitch when run thru a prop calculator with the performance numbers like ratio, RPM's Speed, slip. But they are way more complex than that, in effect varying pitch thru the rpm range. They have cup to them, the rake is very specific, and the differing diameters are designed to develop a synergy not possible with just two alike but reversed props with reverse rotation.

 

[dwhitten]

Re: Volvo Penta F6 Prop specs

what is the different between the f4 and the f6?

 

[Maclin]

Re: Volvo Penta F6 Prop specs

F6 is higher pitch.

 

[moosehead]

Re: Volvo Penta F6 Prop specs

^+1 to Maclin's recommendation. That is a rather large difference in RPM and top end speed at WOT for the same props, which suggests a bit of ham fisted wrenching on those screws.

I have also tried in vain to get relative pitch comps for the VP Duos. For reference, I have the same 5.7 GXI and VP Duos at 8,200' elevation in a 3,800 lb. dry weight runabout. WOT with the F6 lugs at 4,200 RPM and 48 MPH with slow holeshot. The F4 is perfect here at 4,900 RPM and 43 MPH along with much better start out of the hole.

 

[Maclin]

Re: Volvo Penta F6 Prop specs

Volvo gives pitch on their single props but the duoprops are not specced with pitch numbers as you can see from these charts from Volvo by engine and drive....

 

[moosehead]

Re: Volvo Penta F6 Prop specs

...The shop didn't know much about volvo dp's...

This, combined with the complex science of the DP's, might suggest not letting this guy hammer them again even if he can get a set of borrowed block forms. At $1,400 new, the DP's are like jewelry, so you may be better off sending them to a qualified screw tech even if you have to travel or ship them out.

It is tough being in a remote location and either having to go with lesser help or DIY. In my case, I gambled by buying a used reconditioned set of DP's at half of new retail price and just got lucky that they are in semi decent spec range and seem to be working.