Topic: Huntsman Build (Read 22355 times)

Norseman · « **Reply #25 on:** January 15, 2013, 03:40:22 PM »

It will be a total refurbishment and the flexi prop can come out too. It is on my 'to do' list.

Dave

Edit - I will look for one Jan - I will let you know if I find one

Steve · « **Reply #26 on:** January 15, 2013, 04:36:24 PM »

Hiya Jan,
In response to what you said about cooling, to be honest I don't have a clue how hot they run, but as you said the contact area is small so thats why I made a close fitting coil and covered the whole length of the 900 to increase the area of contact, it maybe over kill or it may not.
But at least now its done I wont have to mess around with it again.
But thanks for your remarks.
Steve.

pompebled · « **Reply #27 on:** January 15, 2013, 08:46:25 PM »

Hi Steve,

If the boat doesn't get too heavy in the end, two 900 motors should not have any trouble moving a 116 cm (46") hull, heat should not be an issue unless you really overdo it on propsize and pitch.
I'd start with a smaller size than the X-55 in your OP to be on the safe side for the first runs.

I'll follow your build with interest.

Regards, Jan.

Steve · « **Reply #28 on:** January 15, 2013, 08:59:00 PM »

Yes thanks for your interest, I hope it helps new people to the hobby.
I have learnt such a lot from this forum and often follow different threads.
My last build was the Robbe Atlantis which was quite a challenge at times but very rewarding.
As its been to cold to be in the shed I have even making the front railing just to keep chugging alongs.

Steve.

Steve · « **Reply #29 on:** January 15, 2013, 09:23:33 PM »

The kit provides a length of brass rod to make the railings, which isn't quite the same as chrome, I had some railings chrome plated on my Atlantis, cost me 70 quid, so as the Huntsman's are alot more straight forward I used 3mm stainless steel tube with brazed joints, I made a perspex template of the bow drilled where the mounting holes would be best positioned and formed the tube to shape.
I also brazed some stainless washers to the tubes where they entered the deck.
I used silverflo 55 brazing rod with easyflo flux, both are quite easy to get hold of on the internet.

Steve.

red181 · « **Reply #30 on:** January 16, 2013, 12:20:16 AM »

nice work on that fender, looks real smart

essex2visuvesi · « **Reply #31 on:** January 16, 2013, 04:39:33 AM »

Quote from: pompebled on January 15, 2013, 10:37:47 AM

Hi RAAArtGunner,

The principle is very simple, a brass tube, soldered onto the brushtab.

As the brushtabs of Speed motors are held in position by plastic, it's essential to work quick, in order to avoid overheating the plastic, which in turn would cause the brushes to move out of position, ruining your motor...

I use a pair of roundnose pliers to bend the tab according the radius of the tube used (usually Ø 4mm thin walled brass) and pre- tin both tab and pipe with a 80-100W soldering iron.

I adapted a wooden washpeg to hold the brass tube in position, so I can solder the two together quickly withouh having to resort to using pliers, which would draw heat from the iron.

The pipe in the picture is too long, shorten it prior to soldering it in place.

I use the same washpeg to hold both cooling pipe and motor wire in place to be able to solder the wire in place without the brass pipe falling off again.

Regards, Jan.

Another quick tip to add to this... heat the tube before soldering so the soldering time is reduced further

Steve · « **Reply #32 on:** January 16, 2013, 07:44:16 PM »

Quote from: pompebled on January 14, 2013, 10:48:27 PM

Hi Steve,

If the 900 motors need thát much cooling, you got the setup all wrong..., hopefully it won't come to that.
As it happens, a coil around the can doesn't constitute much cooling due to the very small contact surface between the can and the tubing.
Adding heatconductive paste and covering the coil with shrinkwrap (to protect your cloths) helps a bit, but if the coil isn't enough, adding brushtab cooling takes away more heat from where it's generated, at the brushes.

If the motor really has to work hard and overheating is a concern, remove the coil and add a full jacket, where the water runs directly on the can (isolated with a thin layer of clear tape to prevent rust), as shown in the picture:

This jacket is so effective, the moisture inside the hull will condensate on it, specially when it's still cold outside...

Regards, Jan.

Can you give me an insight into how these jackets work? is there another plate underneath the jacket with a recess in it to make a cavity between the motor case and the outer jacket?

Steve

pompebled · « **Reply #33 on:** January 16, 2013, 09:25:09 PM »

Hi Steve,

The cavity is formed by a layer of closed cell adhesive foam, running around inside the edge of the brass plate, where the brass tubing is soldered onto.
The foam forms a rim, 2-3 mm wide and by turning o the bolts, the foam is compressed slightly, giving a watertight seal, the waterfilm is only half a mm thick.

I have pictures and a how to on my old computer, but the HD has been damaged so I don't have access to that data; I'm sending the HD to a specialist who'll try and retreive the data tomorrow.
If this works, I'll post the pictures here.

Regards, Jan.

Steve · « **Reply #34 on:** January 18, 2013, 07:40:10 PM »

I have been glueing the propshaft supports today, and fixing the rudder supports along with preparing the linkages.
At the same time I have made a start on the linkages for the trim tabs.
Lots of epoxying to do at the moment, perfect job for the snowy weather.

Steve · « **Reply #35 on:** January 18, 2013, 10:11:16 PM »

Just been checking out a new web site from a supplier I use called Macc Models, they sell lots of raw materials and some quite interesting things also. There classed as a model engineering suppliers.
I can highly recommend them.
http://maccmodels.co.uk

Steve.

Chris G · « **Reply #36 on:** January 19, 2013, 08:07:11 PM »

Steve the build is a credit to you, very impressed.

I built a wooden one 36" some years ago and still love it. I was interested in the 'pulpit' something I never got around to and which makes the model.

If it is of any help I made my windscreen by glueing a plastic open box section to the deck. I then cut out of flexible plexiglass of the dimensions that looked in keeping the screen and glued that into the plastic section. It was finished by glueing the same size open box section onto the top of the screen. Simple really but took many hours and after several years has remained acceptable.

Maybe a few ideas for you to 'tweak'

Chris G

Steve · « **Reply #37 on:** January 20, 2013, 02:59:28 PM »

Hiya Chris thank you for your comments and suggestions, I find it fascinating on here, everyone is there to help and learn.
This weekend I have been sorting out water inlets and outlets plus a few extra webs here and there, the one thing with the Huntsman is once the deck is glued down theres alot less space to be able to access. with fitting working trim tabs I had to remove part of the rear bulkhead.
So alot of planning is required. I also have been offering up speed controllers, deciding were the receivers going to go just so I can get all the brackets struts etc fitted prior to finally epoxying everything up. Then will prime all the wood inside and get it painted prior to fitting the deck.
Will post more pictures later today.
Ta ra for now
Steve.

Steve · « **Reply #38 on:** January 20, 2013, 04:44:09 PM »

After weighing a few things up, Im using a Spektrum receiver powered by a 5 cell 6v pack, I read that the Spektrum will take anything up to 9.6v, So I will keep my other batteries purely for the motors.
As I am also using an Action P94 mixer I will have to use an inline regulator I have looked this up to be an Action P99 this will drop the 6v down to 5v making the voltage safe for the Action electronic components.
The other thing I have been looking at is my water cooling, Im using the standard setup i.e. water scoop behind the props through to the motors and then out through the hull sides.
I was wondering whether to use a car windscreen washer pump.
I bought one the other week for a fiver, the only thing is I would like to use the pump with an Esc to control the flow. Has anyone sourced a Esc that would do the job?
My idea is a "Y" piece from the water scoops through the pump .
then a "Y" piece out to each motor its either that or two pumps which I think would be a bit over the top.

Steve.

essex2visuvesi · « **Reply #39 on:** January 20, 2013, 04:52:47 PM »

most RC car brushed ESC will do the job.... only problem is at full speed it will squirt quite a distance. And they are not self priming... im using a small peristatic(sp) pump on my 36" with a vintage solid state ESC (I need it running at about 40% so more recent ESC's tend to screech)

I have mine setup on a 3 position switch on the TX pos 1 = off, 2 40% (looks almost scale) and pos 3 is panic! full speed. I have a quite funky TX and can set the switch so that the increase from 0-40 and 40-100% takes time (Currently set at about 2 seconds) to take stress off the motor.
it's possible to Y it in to the main drive channel you could end up with a fire monitor type jet from the exhaust

pompebled · « **Reply #40 on:** January 20, 2013, 05:46:23 PM »

Hi Steve,

When the drive train is dialed in properly, I think you can do without the extra hassle of a pump feeding the cooling circuit, if you use a pressurefree system, consisting of an intake behind the prop, angled forward and an outlet out of the propwash under the hull, slanted towards the transom.

This rearward facing outlet creates suction once the system has been filled (by running the boat forward).
Once the air is out of the tubing the flow in the system keeps going, even when you're making the model reverse.

I even use this pressureless system in my fast electrics, where everything sticking out under the hull causes drag, so on those hulls, the inlet and outlet are sanded flush with the hull and still work flawlessly:

Running the tubing inside the hull as low as possible helps getting the flow going, also avoid long lines of silicon tubing, the drag inside is very high.
I use 4 mm thin walled aluminum tubing for the long stretches and only use silicon tubing near the motor (and ESC if required).

Granted, you don't have water coming out of the exhausts, but for that purpose a peristaltic pump would work better than a windscreen washerpump with it's high output (and powerconsumption!).
Also keep in mind the average windscreen washer pump isn't designed to run continuously, the motor is just a simple 540 type, which will overheat quickly when it has to work permanently (don't ask how I found that out...)

I don't recall you mentioning which ESC's you're going to use, but, unless they are extremely efficient and/or much bigger than required, most ESC's tend to run warm/hot when the motor is running partial throttle for a prolonged time.
Adding watercooling may be an option.

Regards, Jan.

Steve · « **Reply #41 on:** January 20, 2013, 06:09:05 PM »

I have put my outlets through the side of the hull close to the motors, is this correct? or would they exit through the exhausts in the transom..these are all things Im unsure about.

Steve.

essex2visuvesi · « **Reply #42 on:** January 20, 2013, 06:13:20 PM »

I have my outlet on the transom

My mistake was having the outlet too high, which caused problems with the unpressurised system hence the need for a pump.

As they say there's more than one way to skin a cat! :)

Steve · « **Reply #43 on:** January 20, 2013, 06:16:48 PM »

Ok thanks, I was going to put mine in the transom, maybe I still will !!!
Is your outlet above the water line I presume it is.

Steve.

Steve · « **Reply #44 on:** January 20, 2013, 06:18:45 PM »

Oh I forgot to ask where do you get these pumps from?
I have a channel with a potentiometer on so I can adjust the flow to what ever suits.

Steve.

Steve · « **Reply #45 on:** January 20, 2013, 08:31:33 PM »

Thinking on....I was going to reproduce the exhaust pipes at the transom (Just for show)
I could connect the water outlet to these couldn't I?

Steve.

triumphjon · « **Reply #46 on:** January 20, 2013, 08:46:54 PM »

on the full sized vessel , the cooling water exits through the exhaust , this has two benifits as it assists quietening the exhaust noise as well as cooling the exhaust gasses

Steve · « **Reply #47 on:** January 20, 2013, 08:56:34 PM »

Cheers mate you have made my mind up for me, Im going to adapt the exhausts to get rid of the cooling water.

Steve.

pompebled · « **Reply #48 on:** January 20, 2013, 08:57:00 PM »

Quote from: Steve on January 20, 2013, 06:09:05 PM

I have put my outlets through the side of the hull close to the motors, is this correct? or would they exit through the exhausts in the transom..these are all things Im unsure about.Steve.

Hi Steve,

Exiting through the side is the shortest way (= less drag) and allows you to see if there's flow in the cooling system.
Should the flow be not sufficient or stop when moving slow, replacing the exits to the bottom, slanted rearward will add suction, making the flow more constant and reliable at low speed.

Running them through the fake exhaust adds drag and compromizes a low flow system, better add a peristaltic pump for such a gadget.

Regards, Jan.

Steve · « **Reply #49 on:** January 20, 2013, 08:59:12 PM »

where can i get these pumps from mate?

Steve.

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Author Topic: Huntsman Build (Read 22355 times)