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Author Topic: Fast electric deep vee monohull build  (Read 13879 times)

pompebled

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Re: Fast electric deep vee monohull build
« Reply #25 on: April 15, 2013, 02:29:00 PM »

Hi Mike,

Should you do for a reversed set up, keep in mind that cornering left will be much smoother than right, due to the propwalk in the other direction.
If you're going to run with buddies with 'normal' propwalk, you'll be at a disadvantage when the track is counterclockwise...

Regards, Jan.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #26 on: April 16, 2013, 01:52:33 AM »

I have moved the stinger now and repositioned it centrally. Im not racing anyone so course direction isnt an issue. Im using a 4mm flex shaft. If need to change props to imperial sizes ill use a prop adapter. The seal isnt foam, its a window and door rubber 'P' seal that has a sticky back to it.
http://www.astrodraft.com/astro_glazing_seals.html
I compress the seal down with the hatch lid, then pins hold it down and in place, it worked very well on the cat and im confident about it on this hull too. I dont mind hatch tape but it pulls the paint off my other boats and its awkward on a windy day to cut from the roll. If i should have problems with it ill revert back to tape :-))
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martno1fan

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Re: Fast electric deep vee monohull build
« Reply #27 on: April 16, 2013, 09:16:47 AM »

A good tape ive used before was 3m magic tape it doesnt bring off the paint or leave residue.I used it on my radio boxe lids for a while before i got screw down lids never had it come off even in a 60 mph summersault and 4 back flips lol.
Mart
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pompebled

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Re: Fast electric deep vee monohull build
« Reply #28 on: April 16, 2013, 11:18:26 AM »

I have moved the stinger now and repositioned it centrally. I'm not racing anyone so course direction isn't an issue.
Hi Mike,

You'll experience the wisdom of that decision as soon as the boatspeed approaches 40 mph.

As you'll have to steer left continuously to run straight, the rudderblade will start to act as a lever when the speed goes up, pushing the left side into the water while lifting the right rear.
Expect some violent flips and (depending on the speed) severe handling issues.

You can effectively skip the first word of the topic title, or add 'looking' between the first and second word.

Regards, Jan.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #29 on: April 16, 2013, 11:47:59 PM »

Hi Mike,

You'll experience the wisdom of that decision as soon as the boatspeed approaches 40 mph.

As you'll have to steer left continuously to run straight, the rudderblade will start to act as a lever when the speed goes up, pushing the left side into the water while lifting the right rear.
Expect some violent flips and (depending on the speed) severe handling issues.

You can effectively skip the first word of the topic title, or add 'looking' between the first and second word.

Regards, Jan.
I am aware and expect there maybe issues with my boat and set up. I decided on going centrally with my stinger as it is the lowest point in the hull, the lowest point being if I'm not mistaken the optimum position to keep the stinger parrel to the waterline for most effective operation. If i had offset the stinger the dead rise angle would have resulted in the stinger being raised on the transom as a consequence. I'm not sure of the effects that this raising will do to the surface drive operation and therefore played it safe by going with something i personally know works with a reasonably positive outcome.

Are there not others with pro effective centrally mounted stingers or am I an exception and consequently doomed to failure?

As regards to the title of my thread. I'm not looking to build a racing boat nor compete in tournaments. Ill be satisfied with speeds up to 40mph, excess of that will be a bonus. The goal of this project is purely for entertainment and the opinionated negative judgment on its performances will remain irrelevant to that cause.
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martno1fan

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Re: Fast electric deep vee monohull build
« Reply #30 on: April 17, 2013, 07:56:39 AM »

Mounting the stinger as low as possible is not allways the best position on all monos .Having it set a little higher has two benefits one been it makes it easier for your motor to spool up the prop but to me the biggest advantage is it settles the transom a little deeper and allows the boat to run smoother rather than skipping arround especially in the turns.Im more used to running larger boats and this is def the case with those take my Apaches for instance the stinger is usually set so its arround 5/16 -1/2" up from the vee .To me personally having it as low as possible will in itself cause some handling issues.I def think offsetting the prop especially on smaller hulls is the way to go.
Mart
Heres an Apache a friends building this shows how high we put them and the offset
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #31 on: April 17, 2013, 08:29:48 AM »

ok ill offset the prop to right. I have removed the prop tube without causing too much damage to the hull.
So how much offset from centre do i need? 3mm?
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #32 on: April 17, 2013, 09:20:27 AM »

ok ill offset the prop to right. I have removed the prop tube without causing too much damage to the hull.
So how much offset from centre do i need? 3mm?
Further research has lead to me this thread and another of jans posts.  Ill position it 4-5mm to right.
http://www.rcgroups.com/forums/showthread.php?t=1656789
I better do as im told  :((
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martno1fan

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Re: Fast electric deep vee monohull build
« Reply #33 on: April 17, 2013, 09:27:36 AM »

Hi Mike please dont think were telling you what to do im sure Jan is the same as me and is just trying to offer you advice based on our own experiences and what we have learned over the years  :} .
You wont regret offsetting the drive,also what i personally like to do is make the hole into a slot up and down this allows me the option of been able to raise or lower the drive a little if need be by also slotting the bolt holes  a tad, it also allows easier adjustment of the stinger,just seal the hole with silicone to seal it as well as the bolt holes for the stinger.
Mart
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pompebled

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Re: Fast electric deep vee monohull build
« Reply #34 on: April 17, 2013, 04:59:53 PM »

Hi Mike,

As Mart said, we're only offering advice based on our own experience, we're not telling you what to do...

But, as we've made a lot of the setup mistakes ourselves (at least I know I did) and know what devastating effect these can have on the running attitude, we like to keep you from repeating them.

Regards, Jan.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #35 on: April 17, 2013, 11:48:31 PM »

I know you are both helping i was only joking about doing as i am told. I suppose i was a bit irritated about having to pull the propshaft out again after reparing the damage caused the first time round.  I was preparing to the take risks of the possible outcome in order to get out of moving the stinger again, plus i felt  a little insulted and rebellious towards Jans advice after his comment on my thread title, a clearly petty reaction on my behalf. At the end of the day it would be foolish of me not to take the experienced advice both of you have offered and for that i am grateful.
I have moved it 4.5mm right and reinstalled the flex tube. Althogh a good idea I wont be cutting a slot as the hull being wood if i cut anymore holes in this transom it'll lose its integrity around the stinger mounting plate.
thanks :-))
 
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #36 on: April 18, 2013, 09:32:08 PM »

Ive deviated a away from the hardware a bit and did the hatch. It made from bread and buttered balsa then wittled and sanded to shape, it still needs some work but you get the idea.
 
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martno1fan

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Re: Fast electric deep vee monohull build
« Reply #37 on: April 19, 2013, 08:27:05 AM »

Nice will you be covering with some lite cloth and epoxy?.
Mart
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #38 on: May 04, 2013, 09:25:07 PM »

Ive now got a job so my build time has significantly decreased, therefore the build rate will be a bit slow. In the pictures shows the motor mount and the holes drilled for the bolts and steering push rod. I have also added spray rails, epoxy grp'd the hull and painted the underside in grey primer. I started on the top too but i ran out  :embarrassed:
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pompebled

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Re: Fast electric deep vee monohull build
« Reply #39 on: May 04, 2013, 10:26:01 PM »

Hi Mike,

On the pictures it looks as if the brass tube for the flex shaft is curved upward, is that the case or does it look that way in the picture?

Did you use glasscloth and epoxy resin for the bottom?
If not, you should have, as paint alone isn't going to cut it in boats this size...

Regards, Jan.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #40 on: May 05, 2013, 07:45:37 AM »

the brass tube has a smooth S bend in it along the its entire length. It aligns with both the stinger and the motor spindle dead straight.
Yes the hull is glassclothed and epoxied on the bottom. This was my first try at glassing my boats, although not the first time glassing. I usually use dope and tissue and i think i prefer that to glassing.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #41 on: May 24, 2013, 01:17:37 AM »

Sorry its taken such a long time to update this thread. Painting allways gives me grief whatever boat i do and this one is no exception. Besides theres not a lot you can say about painting is there? It just takes a while and with me working now even longer than it use to. I have gone with matt black and green. I did some colour schemes on microsoft paint and its not quite come out the way i visioned it. The bottom is white just it case it flips over. Its probably not the most sensible colour to use matt black but i dont sail to far away from the bank and i dont do it at night time so im not too worried. Im not a good painter so dont judge me too harshly  :embarrassed:
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #42 on: May 24, 2013, 01:25:14 AM »

Hardware installed. Im not sure at the minute how i will arange the batteries. It will either be 2 packs of 2 cell lipos or a singular 4 cell lipo. I have provisions for both by moving the esc to the front. The total displacement of the boat is a little higher than i thought it would be at 1.9kg. Bath test show that it sits quite low which looks good, but i fear will cause issues when the boat climbs onto the plain with the bow going up and the weight shifting to the stern. I do not think there will be any issues at full speed as long as i dont dally about. But at this stage its only a theory.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #43 on: May 24, 2013, 01:28:30 AM »

Im using green plastic cheapo props at the minute so i can test for most suitable propellers. The one on currently is a 42mm 1.4 pitch. Im fairly confident but i would like a metal prop. The rudder blade is not aligned with the prop. I hope i dont have to change it.
 
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #44 on: May 24, 2013, 01:30:36 AM »

Here you can see the rc car body pins holding the deck lid on.
Im not happy with the overall look of the boat, itl do i suppose. Ive got another idea up my sleave and if it works should turn out pretty good i think.
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ardarossan

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Re: Fast electric deep vee monohull build
« Reply #45 on: May 24, 2013, 05:28:42 AM »

Here you can see the rc car body pins holding the deck lid on.
Im not happy with the overall look of the boat, itl do i suppose. Ive got another idea up my sleave and if it works should turn out pretty good i think.

It's never good to read that someone isn't happy with their model - especially when it's one
they've actually built themselves, and there's nothing essentilly wrong with it.

Thererfore, hoping that you don't mind a couple of thoughts on points you've made: With regards to the Pit-pins, you might like to put a nylon washer underneath each one as they'll quickly scratch the Matt Black paintwork, and also, if you attach a trace to each pin, you won't lose it (otherwise carry a couple of spares taped inside the boat).

The other thing is with regard to the paint colours you've used - Red, White and Green are the colours of both Castrol and also of the Italian flag - With that in mind, I've just had a quick play in 'Paint' that may be of interest. The designs use nothing more than simple straight lines plus a couple of vinyl decals...

Andy



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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #46 on: May 24, 2013, 06:07:29 PM »

i saw the pictures before i read the post and thought hmm something seems familiar about that boat it looks like mine %% 
I like the castrol one, though i dont think ill be doing it, not at the minute anyway. Painting is a part of this hobby i loathe, I like my boats painted, just hate painting. Sometimes i seriously consider paying someone to do it for me. Id rather spend the money and have some else do a half decent job rather than me do it. I probably should have come on here for inspiration before i started the painting. Ill take into consideration the use of the washers, if the gap between the pin and the lid allow, Its pretty tight. I have a lot of replacement pit-pins (so thats what theyre called) so if i lose one it wont matter they're ten a penny.
Thanks though  :-))
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #47 on: May 26, 2013, 07:31:17 PM »

I cant help but find it ironic how when i build a boat on the cheap with notoriously unreliable **** it goes perfect yet when I fork out a bit for some posh gear it all goes TU!! >>:-(
The motor i am using is a bl3650 2700kv motor. Im using Turnigy 4s 3ah lipos through a Turnigy 120a marine esc. Its turning a 2 blade 1.4 42mm prop. I changed down to a 40mm only to find the prop is reversed so i dropped even lower to a 38mm and got cavitation. So back to the 42 it was.
What i cant under stand is why can a 2845 3600kv motor spin a 37.5 graupner k series prop for nearly 15 mins and still be cold yet a 3650 2700kv motor struggles with a 42 and overheats! >>:-( Not too much to cause damage but smoke was coming from the motor. The esc kept on cutting out and going into overheat protection mode. I roughly managed overall about 10 mins of run time but that was with the boat on and off the water. I think constantly id get about 7 mins at a guess. But thats 25 amps continuos and thats well with the capabilities of a 120 amp esc and 68amp motor. The speed was pathetic barely 20mph when it was working. It was planing but not enough to it get to really lift. The prop was surfacing peircing properly so i dont think the overheating was due to the prop being submerged.
So what say you brushless boffins? What am i doing wrong? Is it a case that this is just a bad motor or is the smaller one just exceptionally good? I reckon ill change the motor for something else. I still want to use 4s as thats the only thing i can fit in the boat with a half decent capacity. Im thinking of going for a leopard with a slightly higher kv.
Maybe:
http://www.ebay.co.uk/itm/New-rc-boat-Leopard-4-pole-brushless-2860-2730KV-motor-/230962105793?pt=UK_ToysGames_RadioControlled_JN&hash=item35c66a0dc1
with jacket of course
or this:
http://www.hobbyking.com/hobbyking/store/__25091__3660SL_3180kv_Brushless_Inrunner_WaterCooled_.html
this:
http://www.ebay.co.uk/itm/E-Express-to-USA-leopard-3660-3060kv-motor-36WCJ-50mm-water-cooling-jacket-/230962105668?pt=UK_ToysGames_RadioControlled_JN&hash=item35c66a0d44

the kvs are high so ill likely have to go metal props which i was going to anyway.
 
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #48 on: May 27, 2013, 12:02:34 PM »

Its been a bit quiet regaurding the reply to my post so ive gone with me instincts. I bought a 3660 2700kv leopard with a cooling jacket. Fingers crossed.
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Mad_Mike

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Re: Fast electric deep vee monohull build
« Reply #49 on: June 09, 2013, 10:48:15 PM »

Martno1fan if you see this ive sent you a pm about propellers cheers mate
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