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Author Topic: Robbe Seawolf - Static Dive conversion  (Read 19081 times)

essex2visuvesi

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Re: Robbe Seawolf - Static Dive conversion
« Reply #75 on: September 16, 2015, 10:17:25 AM »

Thanks


Sorry posted the link to the wrong stuff!


Meant to link the Grey PVC
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Re: Robbe Seawolf - Static Dive conversion
« Reply #76 on: September 16, 2015, 05:02:27 PM »

Fairy snuff.

Bear in mind a few pointers. As the rack no longer has to take the load of keeping the hull sealed via a retaining bolt,  it only has to be strong and rigid enough to hold the contents. By the same token, much of the rack can remain inside the boat when the halves are separated, with only the motor and control surface servos needing to be attached to the stern half.

A box section tech rack will be very stiff and rigid, even if made out of of light thin plastic. No need to copy Engel with their over engineered racks. Norbert Bruggen's designs tend to be more elegant, worth blagging a few ideas from.

A box section also offers more space to hold equipment than a plate based tech rack, as you can utilize space inside the box, on the  sides, top and bottom, maximising use of the volume inside. Some builders complain that cylinders offer less space than boxes- but this is usually down to bad layout.

essex2visuvesi

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Re: Robbe Seawolf - Static Dive conversion
« Reply #77 on: September 17, 2015, 12:08:53 AM »

My new plan is to go with bulkheads joined with threaded rod. Looks a straightforward way to build and is a tried and tested method.


I can then move the rudder and dive plane servos further back in the hull making the linkages much shorter.
The next question is do I stick with the rubber bag dive system or go for a piston pump?


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Re: Robbe Seawolf - Static Dive conversion
« Reply #78 on: September 17, 2015, 07:11:35 AM »

Studding will do the job, but personally not a huge fan of that method, because it takes up valuable space and adds weight, often where you don't want it. Also it won't be as stiff as the box section method I mentioned.

A piston tank will offer little advantage aside from speeding up the diving time- peristaltics can be a bit slow, thus they lend themselves best to small volume systems unless you build a large pump.

One disadvantage of a piston tank, if you use a single tank, is a shifting c.g. the error might only be small e.g. one or two degrees of positional angle out, which a leveller can often deal with, but that's still enough to affect the running characterisitics of your sub. To put it into simple terms it's a bit like trying to drive a car that pulls to one side a bit, you can probably drive it okay with careful attention to the wheel, but it keeps you busy.

A pump system won't give you that problem unless you have a unbaffled hard tank or you allow the bag to move about inside.

In terms of accuracy, the system you have is very good.
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