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Author Topic: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird  (Read 88395 times)

John W E

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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #200 on: April 20, 2019, 09:01:32 am »


hi ya there Nick


If you have a read again the build article which I did for this plan of the Swordsman I believe I explained the majority of things that you are asking about.  Also have a read of other builds in Masterclass and they will furnish you on bits of advice on couplings & etc. but my main advice would be - and it is strongly recommended - that if this is your first build of a model boat, you stick to what it says on the plan =- thus avoiding serious pitfalls.    It has been mentioned on other threads about deviating from plans and their instructions and how they can cause major problems for them who are new to the game.  :-)


John
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JimG

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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #201 on: April 20, 2019, 09:46:20 am »

Brushless versus Brushed motors?There are a number of pros and cons for each.Brushed tend to be cheaper and are simpler with only two wires and a simpler esc. They do often have a problem with sparking at the brushes which can cause radio interference although less common with 2.4GHz radio, supresser capacitors can be fitted to reduce this. Brushes do wear especially in higher powered motors, racing motors tend to have replaceable brushes because of this. Wear causes the commutator to become dirty increasing the resistance at the brushes causing extra heat and power loss. As they are being used less commercially now there tends to be less variety and different winds to suit different prop sizes.Brushless are inherently more efficient as without the resistance of brushes they lose less power to heat. They do need a special esc but these are now common and simple to use If you want a reversing motor you must make sure you get an esc with reverse, many are for aircraft which do not use reverse. There is a much greater range of brushless motors available with a wider range of windings to suit different props. Often the same size of motor comes in a range of KV settings ( KV is revs per volt) so you can choose one to suit your needs. A scale tug with a large prop will use a low KV motor (500 to 1000) while a fast electric with small diameter prop will need a high KV motor (2000 up).
There are two type of brushless , inrunners or outrunner. The major difference is that an outrunner has the outer casing revolving, tends to be slower revving and give more torque (can turn larger prop). If you are using high power inrunners are easier to cool as the casing does not revolve.If you are using more than one motor then you can use just one esc with brushed but brushless need an esc for each motor.
Jim
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DaveM

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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #202 on: April 20, 2019, 10:08:50 am »

33? This one will do the job very nicely on a 2S pack https://www.componentshop.co.uk/lc2826-17t-1050kv-leopard-outrunner-brushless-motor.html
Or this one on 3S (11.1v). https://hobbyking.com/en_us/turnigy-d2836-11-750kv-brushless-outrunner-motor.html
I have one of these in my 1/12 scale Huntress and it's a cracker. Incidentally either of these motors will fit into the same glass-nylon mount used for the brushed 540 so there's no need to alter any of the ply parts shapes. You can see one of the two grub screws which hold the coupling onto the motor shaft. The other end of the coupling is threaded M4 to match the prop shaft. As for the added complication of a brushless motor installation, the only difference you'll see is that there are three wires from the speed controller as opposed to two. Tricky stuff, eh?  8)
DM
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John W E

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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #203 on: April 20, 2019, 10:25:08 am »

The Fairy  must be the only  type of model boat you have made  Dave  :}
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DaveM

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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #204 on: April 20, 2019, 10:32:47 am »

John

You forget the Model Slipway stuff I did.....but I have to confess to an addiction to Fairey Marine powerboats. Liz says I build them at the wrong scale - she'd prefer 12" = 1ft - but I doubt she'd welcome a 31ft boat sitting in the driveway and it would be wasted on the Trent @ 4mph. My friend Scott Pett has had a Huntsman 31 in his garden since about 2009 and he's still not finished renovating it!
https://photos.google.com/share/AF1QipPYwnZ9HOa2TVcPY1cC0PvUCrbhRBQ9n8wP7xrg63ItNuyUEddcHOdCZz4n1JzfEA/photo/AF1QipO4DocVhtarTF5LtFmzfNmcKh6eY9xZuiws9kk-?key=QU9id0p5eF9GMkM1VDhERTkweFVpQnZBLXBKb2RB
Dave M
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #205 on: April 20, 2019, 01:57:03 pm »

Incidentally either of these motors will fit into the same glass-nylon mount used for the brushed 540 so there's no need to alter any of the ply parts shapes.

Oops! Clanger alert! It's the larger 35mm diameter brushless motors that fit the 540 mount. These 28mm ones fit the 380/400 glass-nylon mounts, so you'd need to alter the top of the keel to cater for that. Sorry-pardon!

DM
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John W E

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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #206 on: April 20, 2019, 03:26:24 pm »


 %) I say old boy, if one sticks to the plan - one has to alter nothing - you didn't have anything to do with the design of that crashing rocket on the moon did you? :-)  that motor didn't work either did it? :-)



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DaveM

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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #207 on: April 20, 2019, 04:32:53 pm »

%) I say old boy, if one sticks to the plan - one has to alter nothing - you didn't have anything to do with the design of that crashing rocket on the moon did you? :-)  that motor didn't work either did it? :-)
Nope, but it wasn't made of plywood and it wasn't brushless either... :P
DM
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John W E

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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #208 on: April 20, 2019, 05:07:24 pm »


hi there, here are two of the best brushless motors you will ever get - even Sir DM will have to agree to this one, especially when the pair of them will fit nicely in a 41 inch Fairy of the Skies and I wonder who has a plan for that sitting on his desk? :-)


John
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #209 on: April 20, 2019, 09:04:20 pm »

Dear all thank you for the interesting information.


Mind you, I'm am bit puzzled about how asking about couplings and prop shafts etc qualifies as deviating from the plans - unless that was referring to using a motor other than the 540 ?


Best regards


Nick

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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #210 on: May 11, 2019, 09:37:04 pm »

Hello All

So it looks like I need a prop shaft that is threaded on one end, but plain (if that is the right word) on the other end ? (No mention of this in the build notes that i can see - but the pictures appear to show a thread on the inboard end - hard to make out whether the outboard end does or not. What is the "normal" practise (if there is one) ? Dave Milbourn seems to imply that his Huntress has a threaded inboard end ( " The other end of the coupling is threaded M4 to match the prop shaft.") , but the outboard end could be either I imagine. I see that some adverts for props that i have seen mention "dog" style props - presumably some kind of spline arrangement (as oposed to a thread) ? But some say "M4" - so presumably M4 metric -but that could mean threaded, or it could just mean the shaft size alone and therefore not necessarily threaded ? Then I guess there is the issue of the thread direction vis-a-vis the shaft turning direction for steaming ahead (i.e. the risk of the prop undoing itself ) ?

Thanks
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #211 on: May 12, 2019, 01:08:48 am »

Nick....


If the propeller has an M4 internal thread, by convention the terminology for the prop shaft for that end is M4........if the diameter of the shaft were also 4.0 mm, it is termed as 4 mm diameter. You may also need a thin width M4 locknut to lock the propeller


Again by convention the coupling 1/2 side of the shaft [near the motor] would be 4 mm diameter which is mated to a close toleranced [reamed] 4 diameter hole in the coupling half.....


The coupling 1/2 for the motor is naturally to suit the motor shaft


These reamed coupling holes minimize run-out and vibration


The mention of "dog style" usually refers to the coupling type, not the propeller


Left hand + right hand propellers usually refer the directional of rotation of the propellers for twin engined vessels.......but both of will have a right hand tapped internal mounting hole
 %)


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RST

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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #212 on: May 12, 2019, 01:50:04 am »

Nick,

Suggest you have a google around for 4mm / M4 prop shafts -the propshaft is "normally" something like 4mm OD for an M4 thread (etc).  4mm prop tube OD's usually 6 or 8mm (your choice, 90% of the time I'd go for 6mm, and for a cpl of I buy the clamp-on oiler saddle now unless an oiler tube is included).  There are still some folk who wouldn't spend their last 'hapenny unles it were for something "proper" imperial, but it's so outdated I wouldn't bother unless you desperately want. 

I personally hate shafts threaded at both ends.  Back in the day I got on OK with them, but I find the last few years everyone seems to cut the threads so the unthreaded length is significantly shorter than the prop tube now (even when I've ordered custom shafts).  I usually find a spinning thread on a plain bearing generates unecessary vibration and noise, plus, if nuts on both ends inadvertantly tighten, it locks the shaft absolutely solid.  Threads on either end of shafts almost always the usual "lefty loosey, righty tighty".

You can google "Dog Drive" propellers to see if you wish -prevalent in the US, usually only ever seen them on racing boats, and dirt cheap Asian eBay toys here.  "Dog Style" I'd argue isn't directly related to either, but more often seen associated with the propeller end on models.  Not worth the hassle unless youre absorbing serious power usually.
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #213 on: May 12, 2019, 01:19:41 pm »

Hi Nick

I've standardised on the maintenance free Raboesh prop shafts that I get from Cornwall Model Boats. I go for the 15000 rpm ones to be on the safe side. They are the more usual threaded prop end and plain motor end.

Yes, they are more expensive, but they are quality and you don't have to mess around with lubricating with oil/grease, and in the scheme of thing i.e. the total cost of the boat, personally I think it's money well spent.

Cornwall model Boats also do a good range of couplings including a dog-leg one (which may be what you are referring to?) from Robbe.

Chris
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #215 on: June 10, 2020, 09:15:16 pm »

Hello all


Would anyone like to suggest a commercially-available rudder that would be a good fit for this Swordsman ? From the plan, the measurements appear to be approx 42 deep, 32 wide at the top, and the height of the shaft approx 65, but with the radiused corners etc, it depends quite where you measure it I guess. I assume that slightly oversize might be better than slightly under ? Presumably too big could cause a capsize in a fast turn, and too small would reduce the effect ?


Thanks.
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #216 on: June 10, 2020, 09:29:41 pm »

I usually pick a rudder from the"raboesh" / "radio active spares" line. Brass ones, comes with tube and arm. But ALWAYS trim it or skin it with a sheath of thin wood or plastic to a rough foil shape then profile it from the side. It's an easy cheat but unbelievable how many folk just slap them on without effort then claim "hand crafted museum" type quality with no thought.  They're a perfectly good base for modifying with absolutely minimal effort and a good working base for about a fiver or less with no real tools.
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #218 on: June 10, 2020, 10:30:48 pm »

Like a lot of folks I use those as well and described as Scale Type Rudders if buying from Cornwall Model Boats but available from many online retailers.

You might have to go for a bigger rudder to get the shaft length that you require as I had to on one of my models but easily cut down to size.


Chris


Edit: Martin posted as I was typing and has kindly provided the links to some of them.
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #219 on: June 18, 2020, 07:48:26 pm »

Thanks for the various replies.


I got hold of a rudder of which the blade was just slightly larger than specified on the plan, so I thought that would be a good start. However, I hadnt appreciated that the tube diameter could be an issue. It would appear that this one has a 5mm shaft, and the tube is about 7mm OD. Given that the keel is 8mm, this is not great, in fact it will just about cut the keel in half in a longditudinal sense. I realise that i could put doublers on, as with the prop shaft, but this is not ideal, I imagine.


Plus there is the point that there is a flange on the bottom of this black plastic tube, which is going to be proud of the bottom of the hull (a point ) , unless recessed into the hull (thereby weakening the hull further). It looks to me that basically this is tailored for a round-bilge / flat bottom, and probably for a thin skin, e.g. grp, but that's just a guess. So this has got me thinking about making a rudder. The plan appears to use a 4mm shaft and approx a 6mm OD tube, perhaps one might even get away with 3 & 5 ?


Anyway, I had a look on ebay etc for supplies, it seems possible to get hold of the materials and not at great expense (hurrah), so if I got some of that, and some brass sheet, the next thing is, the best way to attach the shaft to the blade. Would solder do it ? I have a vague idea that perhaps one might have to braze ? I have a soldering iron, and some flux, but brazing is I think beyond me. On the other hand, perhaps a right-angle bend in the bottom of the shaft to give an "L" shape(viewed from the port side), and then build a blade around that ? How much of a concern is water ingress up the tube (I appreciate that the higher the tube, the less that would be a problem, but am thinking of the "ram" effect of the water moving at high speed past the bottom of the rudder tube).


Thanks



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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #220 on: June 21, 2020, 06:59:28 pm »

As you have the rudder I'd use that and fit some doublers either side of the keel. The flange isn't a problem as you file the area flat where it sits and then fair in with the likes of P38 car body filler. I've done that on two Fairey deep vee hulls without problem.

From memory I had to drill an 8mm hole for the rudders I use as per the previous posts. To be honest even a thinner tube isn't going to leave much left of the keel and even though the skins provide strength I'd still add some doublers to beef the keel up.

Chris
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #221 on: June 21, 2020, 07:08:58 pm »

There's nothing which compels you to use that horrible plastic affair that is supplied - I invariably throw them away. As you say, it's intended for a different type of hull altogether. You could subsitute it with plain brass tube, with ply doublers if necessary.

Dave M
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #222 on: June 22, 2020, 09:17:27 pm »

Thanks Chris and Dave for your answers and the information.


Chris yes that's what I imagined that one would have to do with that flange (create a flat for it), and that's also the point that I was making, that exactly underneath where the rudder tube has cut nearly all if not all of the keel away, one is also then going to chop away at the hull skin.


Dave yes I did wonder about doing what you suggest. As it appears to be about a 5mm shaft, that will take a 6 mm tube to sorround it , looks like the brass tube on fleabay is typically 0.45mm so 6mm OD will give approx 5.1mm ID it seems. I may still try and knock something up from say 3mm rod with a 4mm OD tube, will see how I get on with that.


Now as to motors, I'm still rather confused about this. I understand now that the first two sets of 2-digit numbers on a brushless motor are the dimensions, and that the KV is the number of revs per volt , and that an outrunner gives you more torque than an inrunner, and ditto the wider the motor, and that slower running motors are better for displacement hulls etc, and that the wattage figure is the power level, so far so good. But I'm still somewhat unclear as to how one decides quite what motor would suit a particular hull, I guess what I am unconciously seeking is some magic formula along the lines of "for a planing hull of Length L and width W and weight X you need a motor of Y specification (and presumably a propellor of Z ) (oh and I guess then there's the batteries as well). But presumably no such formula exists, and that it's all somewhat a matter of experience / trial and error etc. I did think that maybe it might be simpler (and cheaper) to get a brushed motor, of the 540/1 specification, but it seems that even there, there are different types / specs of 540/1s (from what i see on reading the specs of such motors on the different sites - different power outputs / wattages / revs etc).


The covering of the hull exterior - i  have heard of "Ezekote" which sounds attractive from the eco and personal  health point of view. I don't want to get involved with fibreglass (have done enough of that on full-size boats), so what kind of tissue would be best to use?


The interior - as I will soon be at the stage of adding the cockpit floor , it seems prudent to put a covering on the undersides of the deck / the internal walls of the topsides etc, while i can get at them - is EzeKote best for that ?


Would it be ok to put spray rails on the bilge panels, they do add something to the look, and if it's ok to do that, presumably it would be better do to it after the wrap / tissue has been applied ?


Thanks


Nick



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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #223 on: June 22, 2020, 10:19:31 pm »


Hi Nick


Rather than being confused I think you've pretty much nailed it as regards brushless motors.  :-))


Being relatively new to the hobby I find brushed motors confusing! Brushless are the way forward so I'd stick with them, they are nicely made anyway!  :-) Let me have a think about the size etc.


As for resin I use Eze-Kote and lightweight cloth - 34g/m2 from Deluxe Materials. Never used anything else and like the fact that you don't have to mix it, no odour and brushes are cleaned in water. You do have to put more coats on to fill the weave but it dries very quickly so you can just keep on adding coats.


Dave has used both, Eze-Kote and epoxy resin and I think prefers the latter. It is harder and fills the weave. I think it can be trickier to position and stick the cloth down though as it's stickier and you can get runs more easily and is harder to sand. Dave can answer this better but I'm very happy with Eze-Kote and find it more than hard enough for the purpose. I use it inside the hull as well.


Yes, put spray rails on the bottom skins, the full sized boats had them. And as you say after the resin and cloth has been applied. You can coat them with resin before painting.


Chris
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Re: Q & A - Swordsman A PLAN FOR BEGINNERS by Bluebird
« Reply #224 on: June 22, 2020, 11:07:32 pm »

Finishing notes here https://www.modelboats.co.uk/news/article/finishing-and-sealing-of-wooden-hulls/18771
I do prefer epoxy resin to the acrylic stuff, but that's no reason not to use Eze-Kote.
A 2830/11 1000kv outrunner or thereabouts will do the job nicely on a 3S LiPo pack and a 30A ESC. I use a 3-blade 32mm Prop Shop General Scale bronze prop for best performance, but a 35mm 2-blade plastic prop will suffice for cheapness.
Dave M
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