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Author Topic: Robbe Seawolf - Static Dive conversion  (Read 19056 times)

essex2visuvesi

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Re: Robbe Seawolf - Static Dive conversion
« Reply #25 on: April 16, 2013, 12:40:22 PM »

No problem the more the merrier!


Maybe I should have moved the servos that end as well! Would have made the control rodding much shorter, but its too late now as the servo mounts are well and truly stuck down!
The servos I used are from my T-Rex 500 clone.  They have a carbonite gear upgrade that is supposed to be almost as strong as metal gears but lighter and quieter.

Already looking at my next subs, but need to find a new job first!
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Re: Robbe Seawolf - Static Dive conversion
« Reply #26 on: April 16, 2013, 01:27:54 PM »

Normal bog standard analogue, plastic geared servos are fine for pretty much any sub. Usually most control rods in model subs are the weak link in the chain. If a servo is struggling, it's usually because there is excessive friction in the glanded seals. Bellows offer the lowest friction, but o-ring type seals aren't excessive either provided the linkage is kept straight.

Unfortunately some builders place the servos too close to the bulkhead/endcaps sometimes, and as a consequence, the small arc that the servo arm swings when operated tends to result in the control rods binding against the glands. A simple lack of mechanical understanding.

Money spent on exotic servos is better invested in a leveller and a good quality receiver. Those definitely give you tangible benefits.

essex2visuvesi

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Re: Robbe Seawolf - Static Dive conversion
« Reply #27 on: April 16, 2013, 02:13:40 PM »

True, but when they are in the bits box it seems silly not to use them :). My sons RC car has a Digital servo for steering for no other reason than it was in the bits box with the added bonus of being a perfect fit.


I have to agree on the RX thing.... the Corona synthesised RX I am using was recommended by Mike at Microgyros and I must say it seems to be pretty good.  I'll definately be buying more
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Re: Robbe Seawolf - Static Dive conversion
« Reply #28 on: April 16, 2013, 02:29:32 PM »

If you have them already, then fair enough. If buying new, then think carefully.

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Re: Robbe Seawolf - Static Dive conversion
« Reply #29 on: April 16, 2013, 02:31:34 PM »

hi essex
pic's as promised mate.
you can see how much space i have on the tec deck almost 10in and the drive batterys sit below the deck.
the ballast system will fit in with no problem (i hope) just need to work out what size ballast bag i will need.
hope it helps mate
regards
mick
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sharkbite0

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Re: Robbe Seawolf - Static Dive conversion
« Reply #30 on: April 16, 2013, 02:37:14 PM »

If you have them already, then fair enough. If buying new, then think carefully.

i agree with subculture think carefully when buying new gear but like you essex i had them in the spair's box. lol
 
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Re: Robbe Seawolf - Static Dive conversion
« Reply #31 on: April 16, 2013, 05:06:15 PM »

Ballast tank/bag size depends on the waterline you want to operate at.

The Seawolf is not a scale boat, so you can please yourself. Small ballast tanks mean quick dive times. Also bear in mind that a high waterline is not an advantage with a spindle hull, as the props tend to ventilate being near the surface and with no shelf (e.g. bottom of hull) above them, and the hull shape is optimised for underwater unlike say a Type VII with it's shipshape bows. So anywhere between 100-300ml should do you fine.

You can use a bag, or make a cylindrical tank from plastic pipe. if you use a system which maintains a part filled ballast tank, you might want to consider mounting a cylindrical tank vertically, this cuts down slosh to a minimum. If you want an example of why try filling a pop bottle half full. Hold it horizontally and tilt it back and forwards, you'll see the water sloshes alarmingly from one end to the other. Now hold it vertical and observe it hardly moves- the exposed water surface area is much reduced.

essex2visuvesi

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Re: Robbe Seawolf - Static Dive conversion
« Reply #32 on: April 16, 2013, 06:15:44 PM »

That's a mighty smart job you have done on that, wish I had seen it before I started mine!


Its interesting that when Robbe updated the Seawolf to V2 they made some good changes to the setup, mainly the method for unscrewing the WTC.  But they then removed the propshaft oiler parts from the V2  :o


I spent ages looking for the parts only to read in the supplement that they have been removed from the V2.... All very odd
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Re: Robbe Seawolf - Static Dive conversion
« Reply #33 on: April 16, 2013, 06:28:45 PM »

A glanded shaft seal is better than grease filled shaft, although converting the standard Navy drive may be problematic, as it has a gearbox. Easier with direct drive.

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Re: Robbe Seawolf - Static Dive conversion
« Reply #34 on: April 16, 2013, 06:53:14 PM »

That's a mighty smart job you have done on that, wish I had seen it before I started mine!


Its interesting that when Robbe updated the Seawolf to V2 they made some good changes to the setup, mainly the method for unscrewing the WTC.  But they then removed the propshaft oiler parts from the V2  :o


I spent ages looking for the parts only to read in the supplement that they have been removed from the V2.... All very odd

thank's for the kind comment's. mine is the version 1 seawolf and came with the oil'er and i moded the  unscrewing of the WTC after reading on the forum about the problems people were having mind you my wife bought my seawolf as a present about 5 years ago and it sat in the loft till now lol so its had time for all the bug's to be worked out be fore i started the build. by the way i see you are using the parts from the neptune sub for the static dive in your boat if you dont mind me asking what was the total cost of all the parts you listed please
regards
mick
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essex2visuvesi

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Re: Robbe Seawolf - Static Dive conversion
« Reply #35 on: April 16, 2013, 07:00:49 PM »

With postage about 80 quid.


I have a spare dive bladder if you are interested? its bigger than the neptune one (I bought a few different sizes for testing purposes).  Ill get the full measurements in the morning
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Re: Robbe Seawolf - Static Dive conversion
« Reply #36 on: April 16, 2013, 07:49:14 PM »

An alternative is a geared pump and vented tank system. Should cost about 10-15, less if you have some hose and plastic pipe, and I'm assuming you already have either a spare servo and a pair of microswitches or a extra reversible ESC. If you haven't then add on another fiver!

Simple and inexpensive to build. Doesn't pressurize the internal WTC either.

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Re: Robbe Seawolf - Static Dive conversion
« Reply #37 on: April 16, 2013, 11:13:26 PM »

With postage about 80 quid.


I have a spare dive bladder if you are interested? its bigger than the neptune one (I bought a few different sizes for testing purposes).  Ill get the full measurements in the morning

thanks essex. by the way just to let you know i have had my seawolf in the test tank (the bath)lol.
for over an houre and im happy to report that not one drop of water got into the water tight compartment so im a verry happy camper  :-))
regards
mick
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essex2visuvesi

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Re: Robbe Seawolf - Static Dive conversion
« Reply #38 on: June 05, 2013, 11:32:21 PM »

Happy to report mine is now electrically operational


Full static dive system working well


front dive plane servo fitted and working
Twin sealed endccaps held well at the bottom of the swimming pool (approx 1m) for 2 hours.  Not a drop of water inside


I think it could be down to the replacement O rings.  The one in the kit had gone "funny" so it was replaced with an O ring from the "O rings, assorted" drawer in the workshop.
Have to find out what they are as they are very soft and almost tacky in texture.






The innards



Thunder tiger dive controller, with full water and overpressure protection



the underbelly showing dive pump, bladder and drive motor, this should keep the C of G perfect



2 lipo packs one running the dive controller and one the drive system both 2200mah but one is 7.4v the other 11.1


on now to the laborious task ove cutting the flood slots.
Does anyone know a quicker way than using a hand file?
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essex2visuvesi

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Re: Robbe Seawolf - Static Dive conversion
« Reply #39 on: June 06, 2013, 01:37:12 PM »

Well I found the weak link in my setup today  <:(
the glued join between the tech rack and the end cap


Everything was working as it should on the bench so I closed up the WTC and put it in the swimming pool and all was well held it at the bottom of the pool for a minute or so and no water ingress.
tested servos, rods work fine, then I switched on the dive pump and the pressure of the bag filling caused the glue joint to fail :(


Back to the drawing board.
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essex2visuvesi

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Re: Robbe Seawolf - Static Dive conversion
« Reply #40 on: June 06, 2013, 02:26:32 PM »

silly idea perhaps but i was thinking i could inflate the bag eithr partially or fully before sealing the wtc
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Re: Robbe Seawolf - Static Dive conversion
« Reply #41 on: June 06, 2013, 03:16:33 PM »

Go back and re-read my reply in post 23, and don't say you weren't warned. Glue the front cap on, and use the bayonet ring on the stern, or you'll be getting constant problems.

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Re: Robbe Seawolf - Static Dive conversion
« Reply #42 on: June 06, 2013, 03:44:45 PM »

Guess you're right  :embarrassed:


That means I have strip the rack and shave 1mm off all round as the pirahna bayonet I have has and internal edge to it that narrows the tube opening.... its not just a butt fit like Norberts version.  This should give a better seal but takes quite a bit more work initially.


Its got me thinking tho that if I have to do that, it might be better (and quicker) to make my own rack


or the demell
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Re: Robbe Seawolf - Static Dive conversion
« Reply #43 on: June 06, 2013, 03:53:54 PM »

The o-rings Robbe use for the endcaps are a softer rubber than your average nitrile o-ring. They're about 55 shore, instead of the usual 70-80 shore. As the fixing only uses one bolt, it's asking quite a lot to pinch it up for not just one but two o-rings, and in addition pressurize the internal space when filling ballast- have a care.

The mods may be a bit of fiddling about, but it's a lot less work than dealing with a flooded sub.

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Re: Robbe Seawolf - Static Dive conversion
« Reply #44 on: June 06, 2013, 04:41:09 PM »


The mods may be a bit of fiddling about, but it's a lot less work than dealing with a flooded sub.


This is true!


I'll fetch the dremell
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Re: Robbe Seawolf - Static Dive conversion
« Reply #45 on: June 06, 2013, 04:57:48 PM »

Good stuff. The tech rack is quite sufficient for the job, so I would only replace it if it is inadequate for housing what you have put into it, which doesn't seem to be the case here. With a bayonet ring in place the rack will no longer be under any tensile stress, so its job becomes a lot easier.

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Re: Robbe Seawolf - Static Dive conversion
« Reply #46 on: June 06, 2013, 05:03:19 PM »

Well if I balls it up its not the end of the world
I now have a backup plan and a backup backup plan :D


Plan A
Set about current rack with a dremmell and sander


Plan B
Build a new tech Rack from scratch


Plan C
Buy one from Pirahna
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Re: Robbe Seawolf - Static Dive conversion
« Reply #47 on: June 06, 2013, 05:07:34 PM »

I have to say, not mad about the Pirahna rack. The design is  good enough, but it's the choice of materials- all that metal adds weight, in the wrong place, plus it can tinker with the radio signal. They could have made it from ABS or lexan, and it would have been more than strong enough and much lighter.

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Re: Robbe Seawolf - Static Dive conversion
« Reply #48 on: June 06, 2013, 06:41:03 PM »

I have been talking to another member on here about having some laser cutting done for a different project so maybe there's an alternative depending on cost.
Got plenty of threaded rod in the workshop.
That's by the by I need to strip the bits off before I start cutting


Well this has certainly been an introduction to model subs :)
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Re: Robbe Seawolf - Static Dive conversion
« Reply #49 on: June 07, 2013, 10:09:01 AM »

Hope you are still enjoying it!
Subs are not very forgiving but are fantastic if you enjoy challenges i.e:
- If it can go wrong - it will.
- Keep it simple and minimise the number of holes.
Many thanks for the postings.
David
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