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Old Mar 13, 2013, 04:11 AM
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Sydney Australia
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Question
Revell type VII dynamic diving setup

Could somebody please give me some advice on setting up a Type VII sub for dynamic diving.I am going for dynamic diving until I can build another WTC for static diving.
My main problem is how to setup the dive plains. Do you have front and rear planes deflecting in the same direction or in opposite directions and what direction do you have them for diving ?
I have tried the sub in the local pond and seem to have plenty of speed and deflecting both planes up as far as I can but it won't dive.
Any help would be greatly appreciated.
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Old Mar 13, 2013, 11:08 AM
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I set up mine so the bow planes worked independently from the aft planes. The bow planes are used for diving and the aft planes are connected to a leveller.
Peace,
Tom
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Old Mar 17, 2013, 08:23 AM
Man from Atlantis
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The boat needs to be ballasted down to decks awash, so just the conning tower is above the water, then it should go under fairly easily.
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Old Mar 17, 2013, 03:25 PM
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sub culture is right on for trimming. Here is a snapshot of my Gato, deck awash. As an added suggestion, this would be the highest I would trim my Gato with ballast tanks flooded (for dynamic diving). Here is a snapshot from my video of the Gato doing some pool runs. This shows where it sat at that time.
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Old Mar 18, 2013, 04:26 PM
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Dynamic diving

Thanks everyone for the advice.I have ballasted the sub with the deck slightly above the water (top line of vents just showing).
I modified the dive planes to operate in opposite directions .The rear dive planes seem to have more influence over the control of the sub than the forward.
Since making the mod to the dive planes and limiting the dives to a shallow angle the sub will now submerge. I will have to play around with the deflection angles of the dive planes to get the dive angles correct.
As I am trying this out in my local pond it's a bit hard to judge whats happening once it's submerged.I don't have the luxury of a backyard pool.
Also the motors are causing me a bit of trouble as the seals I made for the motor shafts are loading them up and drawing extra current.It's a bit difficult finding somebody in Australia that has seals for a 2 mm shaft.Has anybody had any luck sourcing small seals or actually making their own?
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Old Mar 18, 2013, 04:49 PM
Man from Atlantis
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Sounds like you still have it ballasted too high. You need to trim it so the deck is completely awash, with just the sail afloat for a dynamic diver.

Rear planes alway work better because one, they're further away from the boats centre of gravity and secondly in the case of the Type VII they're also in direct flow of the propellers.

To seal a shaft of 2mm, o-rings or silicone tubing are usually used. For o-rings you don't want much compression, just enough to lightly grip the shaft, and use silicone o-rings, not nitrile, as they're softer and resist heat better.
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Old Mar 19, 2013, 12:29 AM
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Originally Posted by Sub culture View Post
Sounds like you still have it ballasted too high. You need to trim it so the deck is completely awash, with just the sail afloat for a dynamic diver.

Rear planes alway work better because one, they're further away from the boats centre of gravity and secondly in the case of the Type VII they're also in direct flow of the propellers.

To seal a shaft of 2mm, o-rings or silicone tubing are usually used. For o-rings you don't want much compression, just enough to lightly grip the shaft, and use silicone o-rings, not nitrile, as they're softer and resist heat better.
I was trying to retain some scale realism where it is ballasted.Where it sits now it will submerg quite ok .Do you think it needs to be lower in the water?
I have been using silicone fuel tubing and compressing it lightly with a smalll amount of grease.It is a bit difficult setting the correct amount of compression on the silicone tubing to get a good seal and not overload the motor.
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Old Mar 19, 2013, 01:10 AM
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The lower you get your sub with tanks filled, the slower the forward motion needed to bring your sub under water and overcome the positive buoyancy.
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Old Mar 19, 2013, 05:08 AM
Man from Atlantis
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What Tom said. If you can get it to submerge okay at the waterline you have trimmed to, and you are happy with the underwater speed, then fair enough.

To get a Type VII to run at close to scale underwater speed you need to trim it very low.

Regarding your shaft seals, silicone tubing should work well enough. What type of grease are you using? Post a pic or two of the shaft set-up.
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Old Mar 19, 2013, 06:37 AM
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What Tom said. If you can get it to submerge okay at the waterline you have trimmed to, and you are happy with the underwater speed, then fair enough.

To get a Type VII to run at close to scale underwater speed you need to trim it very low.

Regarding your shaft seals, silicone tubing should work well enough. What type of grease are you using? Post a pic or two of the shaft set-up.
The type of grease I am using is called Supa Lube. It's an Australian product recommended for use on swimming pool equipment and suitable for "o"rings.
I have uploaded three pictures. The first is the bare end plate showing the two motor outputs.Second photo shows silicone tube/seal fitted to left motor shaft.Third photo is flex drive fitted against silicone seal. Small amount of grease applied to seal before fitting and flex drive locked onto shaft with a little pressure against seal.
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Old Mar 19, 2013, 07:07 AM
Man from Atlantis
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Not familiar with that brand, but many greases sold as 'suitable for o-rings' are silicone based. Fine for use on most o-rings based on nitrile, neoprene, EPDM etc., but paradoxically not silicone- it makes them swell up. Check the side of the tin/tube, it should tell you what's in it. if it says silicone, save it for nitrile seals.

Use a PTFE based grease (best), cooking fat (e.g. lard) or vaseline on silicone seals.
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Old Mar 19, 2013, 11:09 PM
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Not familiar with that brand, but many greases sold as 'suitable for o-rings' are silicone based. Fine for use on most o-rings based on nitrile, neoprene, EPDM etc., but paradoxically not silicone- it makes them swell up. Check the side of the tin/tube, it should tell you what's in it. if it says silicone, save it for nitrile seals.

Use a PTFE based grease (best), cooking fat (e.g. lard) or vaseline on silicone seals.
It doesn't tell you what's in it but recommends it for backwash and control valve "o"rings. I have been using this grease on the motor seals a couple of months now without affecting the silicone seals.
Did a final run on the sub today before strip down to paint and everything went well except when reversing to shore my speed was a little high and struck a rock which broke one of the prop guards off and never to be seen again.
I replaced it with a lightweight brass one that I manufactured. Looks quite ok.
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Old Mar 20, 2013, 10:28 AM
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Photos......must.....have...... photos...
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Old Mar 21, 2013, 03:43 PM
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Photos......must.....have...... photos...
My apologies I will make an effort to post photos when I have the sub back together.
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Old Mar 21, 2013, 06:05 PM
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No worries, just busting your chops....I love seeing the work others do. We all learn from them (except for those few that know it all already - you know who you are LOL)
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