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Author Topic: Fast electric deep vee monohull build  (Read 13995 times)

Mad_Mike

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Fast electric deep vee monohull build
« on: April 09, 2013, 01:33:52 AM »

I have recently acquired some plans for a deep vee monohull from an on-line friend in the US who runs the website
http://www.building-model-boats.com/
I approached him with a request to slightly change some allready available plans but in the end it was decided that the best option and a win win outcome for both of us would be to start again. I get a free plan and he gets some new material to retail on his model boat plans website.
Here goes:
I started by getting the plans printed whole on a1 sheets of paper, as you can imagine this saved a lot of time and alignment problems rummaging through a jigsaw of a4 printouts. The template shapes were roughly cut out of the paper and stuck down and backed to piece of thin card. Experience has taught me to use Prittstick to do this as pva glue makes the templates crinkle and shrivel during drying.
 
 
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #1 on: April 09, 2013, 01:42:10 AM »

I cut the shapes out and drew round them on 1.5mm birch ply. I try to waste as little space as possibly when positioning the templates, especially for smaller parts as they can fit into the gaps amongst the larger sections. So far i have cut out the chine shelf, this part will have the bulkheads and formers fixed to it. Ill update after i made some more progress.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #2 on: April 12, 2013, 08:34:28 AM »

For some reason ive gone threw neary a dozen blades building this boat, ive never had this issue before. Ive changed my cutting board and its harder than my last one, i think its that. Anyway these are all the parts for the frame cut out.
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Tug-Kenny

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Re: Fast electric deep vee monohull build
« Reply #3 on: April 12, 2013, 10:13:11 AM »


Have you tried the modeller's cutting mat ?


Ken

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martno1fan

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Re: Fast electric deep vee monohull build
« Reply #4 on: April 12, 2013, 12:29:01 PM »

Looks good Mike what size is she,whats the plan as regards powerplant etc.
Mart
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #5 on: April 12, 2013, 09:56:54 PM »

Looks good Mike what size is she,whats the plan as regards powerplant etc.
Mart
she is 700mm bow to transom. Im planning on using a 2700 kv 3650 inrunner on 4s. Props im not sure. I have a 4mm stinger and im thinking of using 40mm props but ideally i would like to use an octura x440. I can buy the prop but i do not have the expertise or equipment to balance and sharpen it. Prestwich use to but no longer do this service. Until i can find a ready made one im stuck with plastic gear.
Have you tried the modeller's cutting mat ?


Ken
no i havent got one. Im using the side of a wardrboe to save the dining room table but my older one was the back of the wardrobe which was a bit freindlier in my knives.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #6 on: April 12, 2013, 10:04:13 PM »

The progress of my thread is misleading as the progress on my boat is far beyond what is written. I tried to upload earlier several times but i was getting issues.
After the peices were cut the first sections were glued togeather. The deck stringers were first fixed along the length and reinforced and joints with blocks. In any build ive done these first fixing are allways tricky and need a bit verbal persuasion. Shouting and swearing at it helped enormously, plus a little bit of epoxy. A right mess but wont be seen so who cares.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #7 on: April 12, 2013, 10:11:08 PM »

The forward deck stringer and bulkheads were fitted next. All joints and angles are reinforced with a block.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #8 on: April 12, 2013, 10:21:09 PM »

My original intention was to use a solid propshaft for the surface peircing. I have used these before and had success with them, they are cheaper than flex shafts and eaiser to maintain, there downside is they can be quite noisy, even if the couplings are perfectly aligned a slight bit of off balance on the prop and the the sound can be defening. With this original intention i requested that the access hatch on the boat be massive to allow the motor to be postioned way forward and for easy maintenance access. Since im now using a shorter flex drive ive downsized the hatch to increase rigidity. The front and rear edges of the hatch have been edged with 2 batons whihc are screwed from the sides through the deck stringers.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #9 on: April 12, 2013, 10:30:28 PM »

The last picture of the batons shows the screws slightly out, this is because one of the screws i had started to split the wood. Its only a temporary fix until the glues have fully gone off, the deck on top will further reinforce these batons.
I next started on the chine sides. The plans have the side, top and bottom skins allready pre shaped, it is a simple case of copying them to the ply and cutting them out. The use of the chine shelf and deck stringers keeps the frame and formers rigid and square during construction. As a result the pre shaped chines fit almostly perfectly, laser cutted parts would fit like a jig saw puzzle. Upon fixing they are also reinforced with block along the seems. I went belt and braces at the corners with some epoxy. 
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #10 on: April 12, 2013, 10:33:38 PM »

The bottoms were then cut out after the edges off the hull were smartened up a bit, they are also preshaped on the plan. They were also attached. Lots of tape was used to hold it down while it dried.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #11 on: April 12, 2013, 11:21:48 PM »

The second bottom skin was fixed and the edges were smartened up. I reinforced the inside seams between the chines and bottom with 2 blocks running along the inside of the hull. The deck went on next, the boat by this stages wasnt quite exact to plan and the pre shaped template was slightly to small. I simply laid the hull deck down on the ply and drew around it, using the original template, i roughly marked out the hole for the access hatch. Once the glue had gone off, the central section of the bulkheads were then cut out. The edges of the hatch still need trimming flush. I reinforced the joint between the two skins in the bottom of the hull. I laid a strip of ply long the length of the seam and fixed it with epoxy. The first application of epoxy didnt go off properly and had to be scraped off and some new reapplied. This has left that joint a little untidy, but with the motor and propshaft going down the centre aswell im hoping it wont be too noticeable.
 
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pompebled

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Re: Fast electric deep vee monohull build
« Reply #12 on: April 13, 2013, 09:31:57 PM »

Hi Mike,

Your build is coming along nicely!

Regarding your propulsion plans; with 2700Kv on 4S you'll have close to 40.000 rpm unloaded, a 40 mm prop will be on the edge, as I can tell from experience, unless the pitch is lower than 1,4.

Also, as you'll no doubt know, your runs will be extremely short, as a plastic prop, even the Graupner K-series, will shed it's blades within feet as soon as the boat jumps a small wave when running full throttle...

I couldn't run anything bigger than a 31 mm metalprop on my 25" stepped hull with a 3660 2700Kv motor on 4S, I fried an ESC on the first testrun with a 40 mm Graupner prop, because I couldn't get beyond half throttle without flipping the boat... (violently).

As the boat had a floodchamber, I kept trying to get the boat to run full throttle, only to flip is again and again, until the ESC decided it had had enough.

As your boat doesn't seem to have a floodchamber (yet), you won't fry the ESC, as either, you'll have flipped the boat after a few feet, or the prop will be bladeless...

Regards, Jan.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #13 on: April 13, 2013, 09:54:56 PM »

you would have thought so but the motor and graupner 40mm prop are from my catamaran and ive allready had it running. Ive just shelved the cat because the strut angle needs messing about with and i dont know enough about cats or there planing characteristics to make the right adjustments.  Intially i had a 2000kv outrunner on 5s with the cat, 40mm graupner it went well but it had overheating issues. So i swapped for this 2700kv inrunner on 4s same prop, it went slower not sure why {:-{ , despite the fact it had a higher unloaded rpm. This is the motor:
http://www.giantshark.co.uk/bl3650-2700kv-watercooled-inrunner-motor-p-404993.html
I understand these hulls better than cats so i can make better adjustments. What throws me is that a 2845 3600kv motor on 3s will turn a 37.5k series no problem and barely get warm, so i would have thought that a 3650 2700kv motor would easy spin a 40mm prop, i just cant fathom why it went slower.
This boat wont have a flood chamber as is not incoperated into the design. Although i think with some rethinking it could be on the plan for the future. 
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martno1fan

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Re: Fast electric deep vee monohull build
« Reply #14 on: April 13, 2013, 11:04:53 PM »

Looking good Mike,as regards props i can get nice cnc alloy props in dif sizes ive just installed these two on a build im doing using twin 4074 1050 kv motors on 6s,these are 42 mm, probs on the small side but i also have a few bigger ones to try.If you need any let me know and ill get you a price from my suppliers.
Been installing a carbon sub frame inside to put all the parts on came out great,made the carbon plate myself.
Mart
 
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #15 on: April 14, 2013, 01:13:04 AM »

some pretty meaty motors in there. What esc's are those?
Ill likely chase you up on that offer of propellers at a later date, see how funds are. thanks  :-))
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martno1fan

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Re: Fast electric deep vee monohull build
« Reply #16 on: April 14, 2013, 09:18:28 AM »

Yea i had these left over so thought id use them ,im a  dealer of the new sss motors from China i just didnt have any this size smallest i had was 4092 versions and im saving those for a bigger hull probably a cat.Also going to be starting a 58 Apache with the big 5694 versions soon  :} .
These esc are only cheap HK ones,they should work as a friends used them in his Apache on 6s with good results so ill try them,any problems ill change them for something better, t 180,s  maybe when i get more in.
No worries about the props ill email you a list of what props i can get and prices if you wish, props come really sharp and balanced.
Mart
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pompebled

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Re: Fast electric deep vee monohull build
« Reply #17 on: April 14, 2013, 11:24:54 AM »

Intially i had a 2000kv outrunner on 5s with the cat, 40mm graupner it went well but it had overheating issues. So i swapped for this 2700kv inrunner on 4s same prop, it went slower not sure why {:-{ , despite the fact it had a higher unloaded rpm. This is the motor:
http://www.giantshark.co.uk/bl3650-2700kv-watercooled-inrunner-motor-p-404993.html
Hi Mike,

A lot depends on the setup being spot on, but I suspect the multipole outrunner has more torque over the two pole in runner, causing it to bog down under load.

When the outrunner is used without a watercooled mount, heatbuild up can be an issue.
I have all my outrunners on a watercooled mount and when I prop them right, nothing overheats.

Regards, Jan.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #18 on: April 14, 2013, 11:24:39 PM »

the motor i had was in it was a venom v500 2000kv outrunner, here is one though this isnt where i purchased it:
http://www.rchobbyexplosion.com/Venom_V500_Marine_Brushless_Outrunner_2000Kv_p/ven1366.htm
I ran it on 4s at first and the temps were fine but a bit slow, upping to 5s and i got the speed but the overheating problems came aswell. Various sources claim that the motor can run on 5s, whereas some such as the one above say 4s. The outrunner has a fan on the end which draws air through the motor, i used a water cooled motor mount and even modified the motor to allow the air to flow through the can easier. Even with all this it still got hot.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #19 on: April 15, 2013, 01:36:24 AM »

ive made some progress on the hatch. I designed my hatch so that it sits on a rubber seal. When the hatch lid in on it will press against this seal to keep the water out. The seal will be mounted around the inner edge of the hatch on a rebate and then the lid will be held down with rc car body clips through posts.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #20 on: April 15, 2013, 02:14:24 AM »

I think ive made a mistake and mounted my offset propshaft on the wrong side. Ive just read here that it should be on the right. I thought the offset prevent the torque roll it seems that is just recorrects the turning right affects off the torque roll by making the boat steer left.
http://www.fastelectrics.net/prop_effects.php
Also i think the propshaft is too high now ive moved it over. what do you people think. its 4mm higher from the bottom off the hull.
I shouldve just put it in the centre,
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martno1fan

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Re: Fast electric deep vee monohull build
« Reply #21 on: April 15, 2013, 08:23:29 AM »

Hi Mike yes wrong side,main reason we put them on the right is to correct prop walk,when the props spinning it makes the transom want to walk left which makes the boat veer right,having the prop slightly over on the right counter acts that a little.Best thing to overcome prop walk is to have a nice sharp balanced prop.If i were you id move it over to the right,just cover the hole you have with some thin ply on the inside and fill the outer with some body filler then redrill your hole to the other side.
Mart
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #22 on: April 15, 2013, 08:57:04 AM »

pants better get the sandpaper out. :((
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pompebled

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Re: Fast electric deep vee monohull build
« Reply #23 on: April 15, 2013, 10:46:47 AM »

Hi Mike,

If you don't fancy moving the strut to the right, there's always the option to go clockwise...
Downside to that would be the purchase of a counter rotating flexshaft and having a lot less choice in props.

I'd move the strut.

I wouldn't rely too much om foam to keep the hatch watertight, specially when you motorize sufficiently to enable a flip at high speed...
The only way I managed to get a foam edge to really seal the hull was by pressing it down with six screws.

If you paint the deck with something that will stand up to tape, you can always tape it shut.

Regards, Jan.
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martno1fan

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Re: Fast electric deep vee monohull build
« Reply #24 on: April 15, 2013, 12:09:27 PM »

Yea ill second what Jan said about the hatch id stick with tape forgive the Pun lol.If you dont want to move the stinger you could spin the prop the oposite way like he said ,what size flex are you using as i do have some 3/16 reverse ones here should you decide to go that route.
Mart
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