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[martno1fan]

Nothing wrong with ordering things from China or elsewhere you know,i sell more hulls abroad than i do in the UK so id be stuck if people only bought from their own country  .

[martno1fan]

While the kv on this is a little lower than ideal it would work for your project.Should get you into the 50s pos more with a big prop but then watch out for prop walk etc,but if you offset things and make sure you get a properly sharpened balanced prop you should be ok .For a lot more £ you could get this one from Dave which has the ideal kv rating but it does come with water jacket .To be honest id rather use these than a 2000 kv motor in a 3ft wooden  boat due to the extra weight when compaired to a  glass hull .

https://hobbyking.com/en_us/dr-mad-thrust-series-motor-4082-1400kv-for-90mm-edf-8s.html
this one gives you 25 k rpm on the water .

http://www.ebay.co.uk/itm/BRUSHLESS-WATERCOOLED-MOTOR-4082-5-BHP-1600kv-rc-boat-40mm-x-82mm-/361392384145?epid=632968362&hash=item5424aa2891:g:0hkAAOSwQPlV~nzN
This one gives you 29 k which is about right

[martno1fan]

This boat is 40" long using 1400 kv motor on 6s ,seems to go well probably around 50 mph .
https://www.youtube.com/watch?v=u9TlqdidbPs

[Gaci4]

Nowt wrong with that boat, not as if I'm racing. I have no problem ordering from abroad, the esc that had the link was not available for UK postage,that why I was looking else where. What would the set up of a 180amp turnigy esc running a 4074-2000 run like ? With regards to the lipos would you use 2x 3s wired in series or just 1x 6s. And what mah to get I assume it's the same with nihm bigger the better?? 

[martno1fan]

The 74 mm can is a little short it wont have the torque needed,far better with the 82 mm length,longer they are the more torque etc . Best way is use two 3 s lipos that way you can put one either side of the motor,well thats how i do it but then i dont run flood chambers in my boats .More mah they have the longer you get to play  .

http://www.ebay.co.uk/itm/FlyColor-Waterproof-Brushless-150A-ESC-With-5-5V-5A-2-6s-BEC-For-RC-Boat-/272783561971?hash=item3f832ad4f3:g:zPIAAOSwixhZfdwB

https://www.banggood.com/FlyColor-Waterproof-Brushless-150A-ESC-With-5_5V-5A-2-6s-BEC-For-RC-Boat-p-1162279.html?rmmds=search

[Gaci4]

Cheers Martin. I'll have a look would 180amp esc  be ok to cover a vast amount of motors that I would be in the market for?

[martno1fan]

Cheers Martin. I'll have a look would 180amp esc  be ok to cover a vast amount of motors that I would be in the market for?

The T 180 esc is better than the flycolor one but the 150 flycolor one will work well for you its up to you i guess.

[Gaci4]

I'll get the turnigy 180amp as the flyby is only sale outside UK 

[pompebled]

1)The esc that had the link was not available for UK postage,that why I was looking else where.
2) What would the set up of a 180amp turnigy esc running a 4074-2000 run like ?
3) With regards to the lipos would you use 2x 3s wired in series or just 1x 6s. And what mah to get I assume it's the same with nihm bigger the better?? 

Hi Grant,

1) This one does: http://www.ebay.com/itm/Flycolor-Waterproof-150A-Brushless-ESC-with-5-5V-5A-BEC-for-RC-Boat/302315187681?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D45702%26meid%3D1dc1f79d0bf6496c93af22539e28c98f%26pid%3D100005%26rk%3D4%26rkt%3D6%26sd%3D141944856772#shpCntId
 
2) It'll run briefly; I've explained this before, 40000 rpm under load is hard on the drivetrain, Chinese hardware won't last very long.
Next to that you can only run a small prop in order to keep the ampdraw within reason.
The Turnigy 180A ESC won't have issues with that motor, nor will the Flycolor 150A ESC.

3) With a motor drawing well over 100A, you need Lipo's that can deliver that current easily, with a capacity (mAh) a high as practical (weight and size) and a C-rate of at least 35, preferably higher.
As I mentioned before, the position of the motor will determen which lipo to choose:

- A long wiredrive with the motor as far forward as the CoG (balance point) will allow, will result in two 3S Lipo's wired in series, sitting upright against the floodchamber wall, in a similar way as the picture of my Arowana.
- A flexshaft, with the motor in the rear of the hull will give a single 6S Lipo in front of the motor, tucked against the floodchamber wall.

Mind you, I would wait with ordering Lipo's untill the hull is built, waterproofed with glasscloth and epoxy on the outside and epoxy on the inside.
This allows you to tape the motor in it's intended position.
Use weights to simulate the weight of either two seperate 3S lipo's, or a single 6S Lipo also taped in their positions in the hull, tape the hatch shut and do a floodchamber test, keeping in mind there will be some extra weight on/near the transom in the form of the drivetrain, the rudder assembly and the servo

Once you've establed which motor/lipo configuration makes the hull flip back up the best, you'll know what to order.

I'm telling you this because I had to modify the floodchamber wall in our Arowana's, so the 4S Lipo would sit upright next to the stuffing tube and the floodchamber would work.
If you know where to look for, you can see in picture, showing the floodchamber exit hole in the transom, that the first section (16 cm) of the vertical wall is bulging into the floodchamber, before running straight forward to the end at the front of the hatch.

I added a few pictures of the floodchamber build in my sons Arowana, who had run one season without one, using the stock 1600Kv motor. This made the boat docile enough (65 km/h) to keep the flips to a minimum during the races.
Once he upgraded to the 3974- 2200Kv motor, the speed went up significantly and running in competition (and for fun) without a floodchamber wasn't so much fun anymore after he spent most of the races bobbing upside down...

As the stuffing tube and motormount were already in place, installing a floodchamber turned out to be a real PITA, due to the lack of proper access.
I made forms from styrofoam, which I covered with a layer of glasscloth and epoxy prior to installing them in the hull, the second layer was applied with all sections in place.
Once the epoxy had cured fully, the styrofoam was removed mechanically and the remaining foam solved with a slosh of Acetone.
After that I could check for leaks (which there were) and fix them.
The pictures show the 'dent' I left for the lipo to fit in.

While I'm at it; at the bottom you can see two pieces of aluminum tubing glassed in the hull, these are the inlet and outlet of the pressureless cooling system I have in nearly all my boats.
The inlet faces forward, the outlet next to if faces towards the rear, creating sucktion when the boat moves.
Once the system has been filled with water, there's flow, even when you're crawling along, not something you will want to do with a fast electric (hard on both motor and ESC), but in a scale model it's a very nice feature.

Regards, Jan.

[Gaci4]

Cheers for photo I can see roughly the width of the flood chamber I know it's up to the end of the hatch,  but was wondering how wide . I thought where you had put slots to allow it to flood quickly to avoid air getting trapped I though about glassing in a air pipe to exhaust the air out down to right hand side of the boat.
Grant

[pompebled]

Hi Grant,

If all air has to be expelled through a single vent at the front of the floodchamber, when the boat is upside down, with the hole in the transom under water, it'll take forever to do so.
Keep in mind the floodchamber will hold something like 2,5L of water.

Try emptying 2,5L through the length and size tube you have in mind to get an idea of how long that'll take.

Another point is clearing the floodchamber after the boat has flipped back up, without slots/holes on top, all air to replace the water will also have to enter through that single pipe, untill the exit hole in the transom is above the waterline, than the water will rush out when you hit the throttle.

Regards, Jan.

[Gaci4]

Just a thought, as probably many have thought before. Would putting a float chamber inside the lid as well?.. ? Looking at the transom of this boat wether to change the shape if it would effect anything above the water line, is that just aesthetics or physics

[pompebled]

Hi Grant,

As your hatch is wood, it'll most likely float, which is easy to test once you've waterproofed it.
If it tends to sink, glue in a piece of poolnoodle, the same stuff Mart advices as flotation.

Make sure to tape down the hatch properly, because when youre testing it the hatch will float after a flip, the rest of the boat will have been flooded as far as the flotation allows....

Having flotation in the form of poolnoodles is better than having sections of the hull closed, waterproofing those sections on the inside could be tricky and what if you hit something that pierces this particular section...
Also, if the closed off section gets moist for some reason, you won't notice that before that piece of hull becomes mushy and soft, often with a little mushroom growth inside...
It's good practice to store a hull with the hatch off, so any moisture can evaporate.

If you change the shape of the transom above the waterline (in what way?) will not affect the running attitude, provided the changes do not add lots of weight high above the waterline.

As you're not racing, the speed of selfrighting isn't very crucial, so the hole in the transom needn't be as huge as in our Arowana's.
A 4-5 mm wide slit, flush with the bottom, as wide as the floodchamber and a slit at the top, to let the water/air in and out is sufficient.

Be prepared for a very slow recovery after a flip, as both filling and emptying the floodchamber will be a lengthy process.

Regards, Jan.

[Gaci4]

Cheers Jan that covers another bit, what should I fibre glass inside the hull before I put top on? I also noticed Martin's hull and top are separate pieces ??


I had in mind that leaving frame 3 and 5 whole so making a chamber which I could also fill with noodle but I get the impression the entire hull is open in the frames ??

[martno1fan]

Just seal the inside with epoxy resin no cloth.Do you really need a flood chamber ? if all sides of your lake are accessible you dont need one they tend to drift in or you can do as i do get a fishing rod with strong line attach a tennis ball and cast to it and reel her in.Or how about another project ? a retrieval boat here's an ideal kit to build as one.
http://zippkits.com/~zippkits/index.php?main_page=product_info&cPath=86&products_id=498

[pompebled]

Hi Grant,

Martin laminates his hulls in a mould using gelcoat, glassfiber and resin (polyester or epoxy), the strength of a laminated hull comes from the type of glass used and the number of layers.

Laminating a hull and deck in one piece can be done, but only with large hulls, due to the lack of room to work inside the mould and is not practical (or cheap, due to the extra time involved).
 Most hulls consist of two parts (three, if you count the hatch), laminated seperately, of which the hull and deck are being joined with glasscloth and resin afterwards.

As far as waterproofing goes, just epoxy resin on the inside will do the job.
Adding glasscloth on both inside and outside creates a sandwich, which is very stiff, making for a very rigid hull, which is good.
Downside of laminating a wooden hull built on frames is getting it to look good due to all the obstacles you'll have to work around, as you can't fold glasscloth over sharp edges, it'll work itself loose with air trapped underneath, this looks crappy and the sandwich construction is compromised.
If you want to add glasscloth inside the bottom of the hull, you'll have to cut the glasscloth into squares and rectangle pieces that fit exactly in between the frames.

If you decide to do this, read up on the subject of laminating, view some how-to videos, get a pair of ceramic scissors and use hairspray on the cloth prior to cutting to avoid it fraying all over the place (been there, done that, made a real mess of it).

A way around the 'patchwork' laminating inside a hull on frames, would be to add the glasscloth onto the pre cut bottom halves, prior to gluing them onto the frames.

Downside to this way of doing this, is that you'll have to use epoxy to attach the bottom halves onto the frames, as wood glue won't bond with a laminated surface...

Regards, Jan.

[Gaci4]

  love the idea of a tug boat going go get it when it's in the poop?. Just been and got the board to fix the frames to, measure it all out and away we go, once the bottom is on and all dry I'll just epoxy the inside, I think I will fibreglass the hull inside where it's open.


Whether I go for a flood chamber or a tug boat, how many times am I going to roll it and not be able to retrieve it, as I'm not going go be racing just having fun. Just one what is and where is the cline?? I think that what it was.


Grant

[pompebled]

Hi Grant,

I have several fast electrics an only one (the first one I ever bought) has no floodchamber, as the batteries at that time were NiMH and distributing seven of them in the hull didn't leave any room for a floodchamber, as the hull is just 50 cm long.

With the introduction of the brushless motors and Lipo's into the racing world, the hull was too small to cope with the brushless power and was shelved.
Some time ago I put a small watercooled outrunner in this hull and I'm now running it regulary on 2S.
https://hobbyking.com/en_us/ads400l-water-cooled-brushless-outrunner-3700kv-600w.html
The motor can handle 3S, but the hull cannot, it's way overpowered with this small outrunner.
Gunning it from a standstill makes it barrelroll...

From all my boats this one is fun to run, but I always have a markerbuoy with 30 m of Ø 3mm nylon line at hand (my version of a tennisball on a fishing rod), as a flip is never far away, specially is it's choppy.
At speed, there's just the prop and the rudderblade in the water, running on the last inch of the hull.

All my speedboats, bought since that first one, have had floodchambers installed, it makes running them, without clinched buttocks, so much more relaxed...

Retreiving a flipped speedboat with a tug is quite a challenge when it's windy and there's chop.
When the boat is far out, seeing what you're doing makes it extra difficult.

I do have a tug, but have used it only once to retreive my Arowana when the ESC gave up running on a slow moving river (Lahn in Germany).
The tug was at standby, but before I had attached the floating line with floatation at the end to the tug, grabbed it's transmitter and got back to the river, the Arowana had floated down stream quite a distance.
Fortunaly I could run along the bank, steering the tug towards the stranded boat, so I had a good view on what to do.
After two attempts, I snagged the rudder and pulled the Arowana to shore.

I do most of my running abroad on the river Weser, which has a current of 6 km/h.
I can tell you a flipped boat is very quickly, very far down stream...

My tug would be useless, as it runs about 6 km/h and can't cope with the full current on it's own, let alone towing something.

When I have access to the bank, the buoy with the line gets used, if that fails, I go swimming (I know, not the smartest way, as a lesser swimmer may drown trying to get his toy back, but when the water isn't freezing, I'm doing allright).

Regards, Jan.

[Gaci4]

I can swim pretty well so I don't mind going in I really have too, I've not built the first boat with out adding another boat to the list. I want to make sure that I'm doing this right, upon gluing the frames together with strip wood, all the frames are open so you can see to the tip of the bow for floatation  just stuff pool noodle through them or leave frame 5 full and make a flotation chamber with noodles behind it, maybe,put small hole at top for it to air?.i can't visualise what Martin  means by a float chamber.
The boat once made will be going in all water pond, lake, river, sea. I do think a flood chamber is a good idea as long as you don't have to constantly be going fast to stop it filling up .......


I was watching a traxxas spartan on you tube on a calm flat lake it was at speed bobing from side to side why is this as it seemed to have an effect to him giving it all out.
Grant

[pompebled]

I do think a flood chamber is a good idea as long as you don't have to constantly be going fast to stop it filling up .......

If that was the case, not a single raceboater would install a floodchamber in his competition boat...
Consider the mass inertia of water; as soon as you get moving forward, the water will exit the floodchamber and will stay out until you stop the boat completely.
Running at a slow speed isn't good for motor and ESC, but it won't cause the floodchamber to fill up, not even a bit.

I was watching a traxxas spartan on you tube on a calm flat lake it was at speed bobing from side to side why is this as it seemed to have an effect to him giving it all out.

Search on 'chine walk'; there's so little boat in the water it starts wobbling from side to side.
Increasing the throttle will cause the boat to spin out as there's nothing (much to counteract propwalk anymore.

Regards, Jan.

[Gaci4]

I had asked about chine some thing or other before as some where I think it was  Martin saying don't forget to add the chine or spray rails ?? All these new words and terminology 

[pompebled]

Strakes are under the hull, chines are the edge between bottom and side of the hull.

Well placed sprayrails sit on the edge of the hull, deflecting the water to the sides, preventing the bow wave from crawling up the sides, which would create massive drag.

When this happens, the water crawling up the bow and sides during acceleration and powering down will reek havoc on the running attitude.

Chine walk occurs when a (well dialed in) hull reaches the limits of it's design, speedwise.
Slowing down, untill there is more hull in the water, is the only way to remedy that.

Regards, Jan.

[Gaci4]

HI Jan, looking at your hulls,it looks like they are the same shape as the strakes.
Grant

[martno1fan]

No need to add spray rails just let the sides hang slightly bellow the bottom then use filler to get the shape and sand to tidy them up see pic.
Personally i wouldnt glass inside the hull its just adding even more weight,wooden boats are strong you dont need it in my opinion.

[pompebled]

HI Jan, looking at your hulls, it looks like they are the same shape as the strakes.

Hi Grant,

I think I know what you mean (too late for me to respond at that hour though...).

The hull at the top of the picture (Arowana) has sprayrails at the chines made the way Martin showed in his picture (a very clever way to do it, by the way).

The bottom one (JetChopper30) is similar, but at the nose you see the sprayrail morph into strakes as they are tucked inside the curve of the hull.
This is due to the rounded nose of the JC30.
If you watch video's of both hulls, the well dialed in ones run in a similar way, with the sprayrails doing their job.

Regards, Jan.