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[hama]

Here's a question to you all.
Knowing that most of the bigger vessels and many of the smaller ones that I've worked on have been fitted with controllable pitch propellers I keep on wondering why there aren't any for our modelboats? I would buy one if there were any available. I did find one many years ago, made by Raebosch, and still have it. I haven't installed it in a boat yet as I haven't built a big enough boat yet, but someday! I remember that they had a bigger version than the one I got but I don't think they produce any of them now. So, now that we have schottels, voith drives and water jets, am I the only one who would love to see a range of CP- props?
Hama.

[catengineman]

I would love a CP system as the vessel I am gathering parts for has one (I need two but different ratios) same vessel two different sizes.

on the thought of why there aren't many around it may be down to cost

R,

[hama]

Hi there catenginman, and thanks for the reply!
You are probably right about the cost, but when you look at the prize for a voith drive I'm thinking that it rather is about interest or demand from the customers. I think that a CP prop on a tugboat for instance would add that extra realism. Would you like to tell us about your project, I'm just a little curious you know?
Best regards
Hama

[Martin (Admin)]

I believe they where mainly designed for steam engines and glow / diesel / petrol engines that don't have reverse, 'stop', fine throttle control or throttle range.

I seem to remember reading an article in one of the older model mags saying that these variable pitch props were not very robust and were prone to damage, flew apart if ran over speed and the blades jammed quiet easily.

[catengineman]

I believe they where mainly designed for steam engines and glow / diesel / petrol engines that don't have reverse, 'stop', fine throttle control or throttle range.

I seem to remember reading an article in one of the older model mags saying that these variable pitch props were not very robust and were prone to damage, flew apart if ran over speed and the blades jammed quiet easily.

Mmm had real one's do that!  One default to astern while under full ahead  not the best thing to happen and the reduction drive didn't much care for it  .

 hama, the project is to construct two sizes of the same vessel (Mv Thames formerly The Arco Thames) I have the GA and drawings but work on them will be slow I want to build the one for ME first but the other for the company will fund MY build, Mine will work the company's will only be display (inc sand) and with the two different scale getting the bits together it taking twice as long. but no rush winter looks to be a long drawn out affair.

R,

[andrewh]

Hama

It may be helpful to know that some brushless motors are made with hollow shafts exactly for variable pitch props
And any that have a solid, but replacable, shaft can have the shaft replaces by suitable tube so that a CP prop can easily be controlled
andrew

[hama]

Catengineman, I think I found your ship.    What a nightmare to build that deck!     But am I right when I assume that you work on this vessel and have first hand information of her? Have never been on a dredger but somehow she reminded me of a cement carrier I worked on, she was designed for selfdischarging on lighter operations to large bulk carriers. Her decks were stuffed with gear, hoses, pipes and cranes! Hope to see some of your build here later, good luck!
Hama.

[catengineman]

Yes  hama i have the pleasure to work aboard the fine vessel 

After several YEARS of sitting idle and out of class we have managed to rebuild her main engine and reclass her then sail it back from Gibraltar to work around the English coast its not all plain sailing though now we are working the ship the age is showing in the equipment that have not replaced (yet)

My model with luck will suck and discharge its own cargo ? well thats my dream and it is possible just going to be very costly and it will all have to be from scratch
Just need to find a good supply of scratch

So far I have the dredge pump, pipe work, drive motor's 1main 1 dredge pump, 3 drain pumps 4 servo winch's, 7 modified servos for equipment operations the batteries receiver lights bow thrust and some ply for the hull.
If I built it at 1/32 it would come out at just under 2.84 meter long!
great for the detail but what a pain to transport!
R,

[hama]

Hey, that sounds great, a working dredger. I remember seeing a large working model dredger somewhere on the net a few years ago. Can't find it now I'm afraid, perhaps you've seen it? There were pictures of the build, test runs, testing the dredge pumps even some pics of it breaking ice! I'll let you know if I find it again.
Hama.

[hama]

Found it!
A bit off topic, but I found the dredger I was talking about. You have to check it out catengineman and everybody else too because its fantastic. There are several photo albums there with many, many wonderfull boats. A very beautiful car/passengerferry for instance.

www.pbase.com/geardsoft/jandenul

Hama

[cos918]

hi there hama. I to have offten thought about CP props . My  next model has cp props (FINNJET). the only reason i can come up with is there is no market. IE on a real ship ,in the old days you had to stop the shaft then start it up in revers ,this took time as with cp it takes a few seconds + you can set your engine at a constin rpm. On a model there is no weight in the shaft so it take no time to go from full ahead to full reverse. so it easy and cheaper to reverse the motor that make a complexity cp prop.

john