The Controllable Pitch Propeller, a summary.

How do you start one of the 8 cyl 2 stroke things if it doesnt have a blower on it?
( 1000 rpm is slow for a 3516)

 

Talk with these guys about mounts.....

http://www.lo-rez.com/products.php?id=6#

 

powerabout

Now we go completely off topic again?
I´m not innocent, I agree.


Yes TAD,

thats the stuff! Thanks.

 

sorry
I guess with every prop goes an engine, its a package.
I assume we are all interested in both?

SO here's a CPP question or 2
Can both the hydraulic and the manual CPP's go to feather?
IF you have twins that are hydraulic can you lock one feathered if motoring on the other?

 

Yes and no to both questions!*

And yes, you are right, propulsion includes engines. But we have more than enough threads on Diesel questions, and it makes it a burden for interested readers to walk through all the non related stuff.


*the common CPP is adjustable from full ahead to full astern at any speed (rpm), with a "neutral" position in between. That is NOT the same as the feathering of a Gori or similar sail prop!
So, a CPP HAS a noticeable drag in neutral!

Regards
Richard

 

On the old yachts I sailed on you could put the old manual Hundested to feather otherwise they would not have been used.
Can you not buy ones that do that anymore?

 

Hundsteds in sailboats so reckon they feather?.. http://www.hundestedpropeller.dk/?id=4177
Some of the Westmekan units are also especially designed for sailboats. However as mentioned before they have a separate control unit for pitch and to be used with a standard gearbox.

 

Correct,

when they are designed for sailing, of course you can feather them. But those are less efficient than the standard "non featherable" CPP.
Same is valid for all those "self adjusting" props.

 

If you expect me to read 10 pages of bitching and fighting you have something else coming.

But since it seems the interesting post have started coming back, I have a question: Richard ...
Can one install a gage that indicates the pitch of the prop at any given time to help finding optimal position with RPM?

 

No,

assuming you meant gauge. The EGT is the best way as I described above. You really should read what was written, there was not only drivel and bitching......

 

Richard,

You say:

"Correct, when they (WestMekan) are designed for sailing, of course you can feather them. But those are less efficient than the standard "non featherable" CPP. Same is valid for all those "self adjusting" props."

I'm not sure I understand this. Why would the WM be less efficient because it can be feathered? Isn't the feathered position just a point between full pitch ahead and full pitch astern? Is the WM not a true CPP system?

You also posted :

"The autoprop is a lot of hype and little advantage! Yes it is more efficient than a fixed prop, in some cases, but has nothing in common with a "Controllable" pitch system. Like the Gori for example it adjusts itself to a sort of "optimal" setting. Rarely that is really the case. But being manually adjustable "controllable" is, what makes these CPP systems so efficient."

I've spent a bit of time re-reviewing the web comments regarding Autoprop and while there are some manufacturing issues the majority opinion seems to be that the Autoprop delivers better speed and fuel effeciency than the owner's previous props. I'm still not sure how the Autoprop arrives at it's "sort of "optimal" setting", but let me ask you this question. If I connected some linkage to an Autoprop, similar to the WM, would I essentially have the same system as the WM, and would that system be something less effcient than a true CPP system? (I would never actually do this of course)

I have two equal motivations for looking at a CPP or CPP-like system. The first is feathering ability in sailing mode, and the second is stong, efficient motoring capability. Is a true CPP system really just designed for motoring and these others are less efficient because they offer a feathering postion?

Best Regards

 

To make it short: The Autoprop and the Westmekan are like a coach and a bike. You cannot compare them. And I did not say WM does feathering props!

feathering costs efficiency, and it is not available at higher power ratings.
second:
a feathering prop is NOT a true CPP! The CPP principle does not allow for feathering.
Feathering requires a movement of the blade parallel to the axle, a CPP moves only across the axle. (or vice versa if you like)
In the real world, a CPP set at a tad above neutral has as little resistance as a feathered prop. A fully foldable has a bit less resistance (Gori for example), but much less efficiency at operating modes under power.
All the "self setting / adjusting" crap is not worth talking. It is the worst of both worlds, not the best. You would need about 50% to 100% more power to operate such nonsense setup compared to a CPP setup.
Of course under common sailing conditions their claims are not too far from reality. Better having a "automatic" system, than a wrong fixed one.

But as long as your application is boat, it is a compromise, sorry. No compromise and it will not float.

I know I did not answer all points, I´ll try later.

Regards
Richard

 

out wartaila's have a scale on the lever and and gauge on the feed back telling you where the blades are percentage wise
we also have a engine load gauge in percent also

 

You mean Wärtsilää.....

Yes on commercial installations that is not uncommon to have a estimating gauge.


Do you plan to install a propulsion like I do?

Do you talk at least one million of dolores Americanes to spend on propulsion?


And, sorry there is no engine load gauge in the entire world.

Are you trying to pull my leg?

Tell them you did fail!


Yesterday you did not know how to spell CPP, now you are talking about "our Wärtsilää"

You cheat!

Leave that please!

 

Give me a break
I am keen to learn about CPP's for pleasure boats as I have a plan to own/build a cruising boat in a few years.
I will not be spending USD 1m on propulsion no more like 350hp range of equipment whatever that costs

I am on a commercial vessel now that has a pair of 750 rpm 5500kw V12's with 4m cpps and all the larger vessels have engine load gauges as its a class requirement that we know where 100% is for continuous power.
The engine will go to 110% for short periods.
With electronic diesels a load gauge is so simple you can get them on almost any new engine with can bus even a 20kw gen set.
Simple when you think about it, the computer has the fuel flow and rpm ( boost) just checks its known operating parameters and tells you where it is
Of course its telling you a percentage of the max.
If the EGT was connected to the computer it could also tell you an overpitched situation for a variable speed engine?
I'm no CPP expert but have operated some form 100kw sailing vessels to the above thats all.