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Dumas Akula

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Dumas Akula

Postby Ahab79 » Sun Jul 15, 2012 1:25 pm

I'm going to start a Dumas Akula. I'm trying to cotact Mike's Subworks for his upgrade kit. But I see he doesn't accept paypal. Due to divorce I'm going credit card free for a year to give my credit a break from the damages a money spending ex-wife did to it.

So:
1. Can anyone suggest a substitute for Mike's upgrade?
2. And what do you guys think of this for my motor and Esc?
www.mtroniks.net/details1.asp/ProductID ... 0combo.htm
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Re: Dumas Akula

Postby JWLaRue » Sun Jul 15, 2012 1:38 pm

According to Mike's web site, he also accepts money orders and checks......seems like an obvious solution.

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Re: Dumas Akula

Postby Crazy Ivan » Sun Jul 15, 2012 2:22 pm

Ahab,
A stock Graupner Speed 400 brushed motor geared down 3:1 and running off 7.2 volts will give that Dumas Akula more than enough speed, while drawing only around 4 Amps. A 4000 mAh battery will provide plenty of runtime for this combination.

I'm no expert on brushless motors, and I don't know how the Mtronics motor compares to the speed 400, but with a 30 Amp capability, that package might be a bit of overkill for that boat. Most subs generally run with brushed motors.
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Re: Dumas Akula

Postby Ahab79 » Sun Jul 15, 2012 11:26 pm

Alright Brushed it is. Cheaper anyway. As for the linkage kit. Well. I just want a secure method of payment. I may have to piece work what I need.

Yet another question has come up though. As I read review after review. And build after build on the Akula (don't worry i'm joing the subcommittee and will try to get back issues of #54 and 56). I ak myself the same question. Why are the WTC's all clear? I can't find any comercial suppliers. Don't want to buy online. Would much rather just use come PVC or something light. And DIY the whole shabang. BUT....am I missing something? Is there some fundamental reason why it's clear? Other than seeing your stuff work?
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Re: Dumas Akula

Postby Sub culture » Mon Jul 16, 2012 7:18 am

Although the majority of WTC's you see are made from clear plastic, usually using polycarbonate/lexan or PMMA/acrylic, not all are.

For instance a UK manufacturer called Sheerline has been making WTC's for their range of models for over twenty years, and they use opaque PVC pipe.

BTW, PVC is actually clear in it's unfilled state, and some suppliers do sell it in that form- tends to be more expensive and harder to source though.

Most people like a clear cylinder as it makes it easier to spot leaks, and also you can see all the guts of the boat- so eye candy.

One thing you need to be mindful of is the tolerance of plastic pipe. Generally the internal tolerance is far inferior to the external tolerance, and in the case of PVC pipe which is used for plumbing, guttering and waste, the inside finish can be very poor. If you're making endcaps which compress the an o-ring seal radially (e.g. on the inside of the pipe) then you can end up with gaps which will mean leaks. You can get around this by either machining a collar to go inside the pipe, seal on the outside of the pipe (which is how plumbing fittings work), or seal axially against the edge of the pipe.
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Re: Dumas Akula

Postby Alexander The Great » Wed Jul 18, 2012 8:00 am

Ahab79,

I'm not trying to steer you off your course, but I know of another place to get your Akula. Rouge Subworks also has this kit, and from when I last checked, there were also upgrades you could also buy like a X-tail conversion set.

If you really want the kit from Rouge Subworks, then you have a couple of choices;

"Kit Only160$"

"Kit With RSW Dynamic WTC 350$"

"Kit With RSW Dynamic WTC and X Tail Conversion 400$"

"Kit With X Tail Conversion $200"

"Buy the kit with WTC and X tail NOW and the X Tail controller is FREE"

I would really recommend buying the kit with at least the RSW Dynamic WTC, as it is WAY better than the WTC provided with the kit, as it resists pressure much better, etc.

The X-tail conversion set is also worth it, as it makes the turning radius of this boat much smaller.

The kit from Mike's Subworks is fine also, as it also has it's upgrades from the original kit, like better seals, etc.

Choose one!

Alex

P.S. Where do you plan to run this boat? By that meaning in a small pond, swimming pool, big lake, the ocean, etc.
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Re: Dumas Akula

Postby Ahab79 » Wed Jul 18, 2012 8:52 am

WOW!!!! Just when I finally have stuff figured out....man...what to do. Lol. I'm about 24 hours away from purchase. So i'll have to weigh the pros and cons. If anything is going to stop me. It's shipping cost. I'm going to see if I can maybe buy the upgrades seperately.

As for where I'm running it. I live in Northern Ontario Canada. "The land of a thousand lakes." I litterally have 6 lakes with in 3 minute drives. If I go out further...endless possibilites.

Thanks for the info. Will keep you posted.
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Re: Dumas Akula

Postby Ahab79 » Wed Jul 18, 2012 9:05 am

I just checked out the site! Awesome. Thank you so much. This is what I've been scouring the internet for. Thank you so much!
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Re: Dumas Akula

Postby Sub culture » Wed Jul 18, 2012 11:55 am

With those upgrades, what is left of the original kit- the outer hull?

If you're sailing in big lakes, I'd advise caution. Dumas specs this boat to 3 feet, I'd say you're pushing your luck even at that modest depth (0.5 PSI at 3 feet) with what looks to me like a vac-formed box.
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Re: Dumas Akula

Postby Ahab79 » Thu Jul 19, 2012 2:06 pm

I've decided against the X tail. But I'm trying to decide how I'm going to build the interior. I'm definatly going to update the WTC. Just having trouble deciding on a few details. I want to upgrade bow planes to operable. I have extra channels up the wazoo. I just don''t know where to put my APC Front or back? Any idea's? Do I run the front and rear bow planes on seperate channels? If I have the APC on lets say rear planes and manual engage them will the APC be overidin?
I'm also going to go with a dynamic dive system. Any suggestions which one I sould go with? I'm thinking bladder. I'm a nurse and I think I can...um...LIBERATE....some cathater bags for the bladder system.

Any idea's?
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Re: Dumas Akula

Postby JWLaRue » Thu Jul 19, 2012 5:14 pm

Standard pratice for boats with both bow (or sail) and stern planes is to use the bow planes to change depth and to use the stern planes to control pitch.

Since you have the spare channel space, definitely run them on separate channels. This would allow you to override the pitch controller in the event that you need to apply a little bias to the pitch controller while running.

I'm also going to go with a dynamic dive system.

From the rest of your post, I think you mean a *static* dive system. :) Static as in the boat does not need any forward motion in order to be able to dive.

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Re: Dumas Akula

Postby Alexander The Great » Thu Jul 19, 2012 6:51 pm

Ahab79,

Do note that the real Akula has retractable bow planes, so you may want to consider this.

As for the kit, you should really buy the thing first, build it, then decide the upgrades you want for the Akula. I've thought up two upgrades that you should apply to the boat, one being to make the boat a static diver, and another to super detail the boat, as the boat in kit form is really plain, no fittings, no scribing, etc.

The WTC should be replaced from the start, as it isn't a good design, because first of, you seal off your electronics so much that access is limited to the size of a bottle cap, second, it is really 'cheap', as it is quite thin, and last of all, it is not cylinderical, so it does not withstand pressure very well at all. This is a problem as I would think that the "land of a thousand lakes" has some very deep lakes, so if you lose the boat, it is very likely that it would be crushed.

Also, there are some important key components missing, mainly a pitch controller, and a fail safe. The pitch controller is needed to keep the sub level, and as one saying goes, "Each model submarine that runs faster than a snail needs a pitch controller" You may also add a depth controller to help the sub remain at periscope depth. There is a pitch and depth controller for sale, so if you want to have these two devices, then you can have them in one unit. The stern planes get connected to the pitch controller, the bow planes to the depth controller.

As for the fail safe, the most important one you need in my opinion is a "missing pulse detector". This device automatically empties the ballast tank if the RC signal is lost, so you don't come home with nothing except a transmitter. There are other fail safes out there too like one that monitors the charge level in the battery, so if it falls under a certain level, it will empty the ballast tank. Also, you could install a leak dectector, so if a major leak occurs, the sub will surface. There is one last fail safe I know of, and it involves using a pressure switch to limit the possible depth your sub may be at. For example, let's say you don't want the sub to descend beyond 4 feet, so you set up the pressure switch to trigger at a depth of 4 feet, so it does not go any deeper.

Don't be too fancy on this boat, it is just a starter kit.

If you have any more questions then post them!

Just making sure you are on the right track.

All the best, and good luck. Alex
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Re: Dumas Akula

Postby JWLaRue » Thu Jul 19, 2012 7:52 pm

re: depth controller

I''d suggest keeping things simple. While a pitch controller is considered my a number of folks, a depth controller shouldn't really be necessary if you get the boat trimmed out properly.

As Alex suggest.....build it as simple as practical, then work on upgrades.

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Re: Dumas Akula

Postby Sub culture » Fri Jul 20, 2012 2:30 am

Wouldn't bother with the front planes. If you make them scale size, they won't work all that well, and a boat of this size and shape will work very happly on the stern planes alone.

Same goes for a ballast system. Build the boat as a dynamic diver first, trim it for low freeboard, and the boat will require minimal speed to submerge.
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Re: Dumas Akula

Postby Ahab79 » Fri Jul 20, 2012 7:11 am

Thank you all so much for the AMAZING ADVICE. Gonna take it all into account. Deffinatlly upgrading to Cylander....and speed control. Rest...we willsee
thanks again gents.
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