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[derekwarner]

So, apart from an impressive build David

......the turntable is probably 8/10,
......the LED lighting [newer additions from 20th November 2020?] about 9/10....
......however you have no excuse for being late for Dinner, with Father Time looking over you @ 10/10 


Looking forward to each new posting............. Derek

[DJW]

Haha... Sounds like my old school report... 'Could do better...'

The LED lighting is part of my day job, but given lockdown.... Well they're getting good use now too.

More varnishing followed by cutting back.










Down to 1000 grit and fine compound now.


Best regards
David.

[DJW]

Evening All


Finished latest cutting back:








Another coat of varnish tomorrow.

[derekwarner]

David..possibly missed this, but have you coated all wooden internals with an epoxy or varnish?


What is the popular view?....do you seal in the nominal humidity % content & hence lock in that value, so any appreciable change in ambient humidity would not cause an issue


The reason I ask is some years ago, similar sized Riviera [Riva?] models from Viet-Nam whilst looking with absolute detail 'and gloss' ...when imported to the USA?....started splitting at internal hull joints, which propagated to the external surfaces at the hull joints 


The popular thought or view on the cracking was due to a change in the moisture level in the wood itself and not a poorly sized or constructed fabrication method

Other Members may relate to this from the dim past, as I believe the subject was posted here on MBM [although not this specific thread].....however yes, a very logical posting from John WE [bluebird]

https://www.modelboatmayhem.co.uk/forum/index.php/topic,13818.msg146031.html#msg146031


Derek

[DJW]

Interesting topic Derek, and a good balanced view from John (Bluebird).


I suspect that you're correct that its mainly down to individuals experience and understanding of the issues. So ask 10 folks and you'll get 10 different rational.


Personally I did seal the interior with thinned Z Poxy finishing resin. Aim was to soak it into the wood. I then applied a second less thinned coat to get a more gloss (smoother, easier to wipe clean) finish. I treated the exterior hull and deck in the same way and used it as a basis for varnish.


To me it seems sensible to get the wood to take up the sealing coat, and from both sides. Adds strength too.


I do keep the temperature stable in my workshop space, and no real humidity issues. The wood spent 6 months in that state before being sealed. So I don't think I've sealed in much moisture, I think that's what could cause a problem. And could be the source of of the cracking issues with the Vietnamese built boats, given the humidity over there, then ship the boat to a less humid place. Asking for trouble in my view.


This is my first wooden hull build in 50 years... and as my earlier boats had to be proofed against diesel and glow fuel, its just a bit of habit too, to seal the interior...


Whether I've got it right...  Watch this space...!


Best regards
David.

[DJW]

Afternoon All


Progress with rear hatch:





And I think final coat of varnish...











There were a few minor  'undulations' on the earlier round of cutting back, I think these should now be improved.  Once cured I'll cut back again, I'm thinking to then leave the hull 'matt' for a while while I get the shafts and rudders in, maybe the white paint on the hull too, then polish.


The varnishing stage does seem to have taken a loooonnng time to build up the coats.  I've made the coats thinner, I think there are 8 or 9 coats on the boat now.  I've not done this building up coats before but have been inspired by UKMikes results, that's the benchmark, if I can get close, I'll be happy.


On the last round of cutting back the 'glass like' finish could start to be seen, super smooth.


Best regards to all.
David.

[Mark T]

That looks stunning!  Honestly I would be scared to put it on the water but I bet its going to look amazing going flat out.

[derekwarner]

Well yes Mark T...all of the superlatives agreed, however I think she will look fast just still in the water 


This LED lighting is an excellent aid to production ....just floods the work area with lightness, and little shadow


Interestingly David.......you say thinned coats of the Varnish we spoke of some time back, but what is the drying/curing time duration you are using especially with the heat created with the Proxxon sander/polisher?


Derek

[DJW]

Thanks for the positive comments chaps. 


If I'm just adding a coat I'll just wait 24 hours. I'm leaving 4 days or more before cutting back, no issues so far. I'm using the proxxon on a slow setting and water with any abrasive disc. Seems to avoid the paper clogging up, and no issues with heat build up. Also when the surface is wet its possible to see any 'glossy' areas, these are the low points, they can then be worked out. A quick wipe off every now and then. 'Rinse and repeat' as they say... Same with the foam pads and compound. A little water seems to help.


And yes the LED panels really help, they're not a point source so give great overall flat light for the current varnishing task.


Best regards
David.

[DJW]

Afternoon / Evening All


Making progress with a flat varnish finish now.  Have resorted to wiping on a 50/50 thinned layer and not brushed...


And several coats, no inclusions, no brushmarks and flatter:








Have been playing with motors and ESC and radio while varnish dries...


And not too happy with the aggressive startup of the brushless motors (Overlander T3530/14).  Seems to me I made a mistake with the cheaper Shark 30A ESCs.  I have the programming card and have tried the various startup options.  Also having some issues getting the two units synced in terms of where they startup.  I have set their end points... Have I missed something obvious..?


Am considering the FrSky Neuron S 40A ESCs as they seem to have a fully programmable interface via PC, so I can guarantee they are both synced.  Also they seem to push back a load of telemetry without extra sensors...  But not cheap...  £50 each...


Any comments gratefully received.
Thanks
David.

[Taranis]

Lovely work David
I can only recommend the hobbywing quicrun that I am using myself.
The Punch setting needs to be at minimum.

https://photos.smugmug.com/Amati-Riva-Aquarama/i-NnLfdJV/0/939b8edc/1920/IMG_5016-1920.mp4

[DJW]

Hi Andy


Thanks for this, and the video is very interesting / enlightening (I do remember you posting it now you mention it...). Your motor startup speed is so much slower than I'm seeing with my setup, and your motors appear to be very well synced, I'm nowhere near that at the moment...  I've set the ESCs to factory defaults and its made no difference.


So the ESCs you're using, you've reset the punch to minimum, any other tweaks to get them to engage slowly, and to synchronise..?


Thanks and regards
David.

[Taranis]

I actually have start mode (punch) set at level 2 of 9, the default is level 5


If yours are not in sync it would indicate to me that the throttle range for each is not set the same.


I would consult the ESC instructions and set each one individually before connecting them together.

[DJW]

Agreed re the throttle range.  To calibrate the Shark ESC the unit has to be started with Tx throttle at max, that's fine, but then it has to be told where neutral is in similar way.  And that's fine for single units, but hard to replicate precisely for two.  Next step is to fit the centre spring back to the throttle stick to try to get a consistent neutral position...


Just spoke to Leeds Model Shop (they supplied them) re the Sharks being too vicious on startup, they reckon it's because I'm testing with no load...  Not fully convinced, but will look again...

[Taranis]

No load is a loser of a theory
As demonstrated mine have no load on them

[DJW]

Agreed re the 'no load'...


I've spoken to Overlander who've very kindly offered to send over a loan of one of their ESCs for me to test with.  This will confirm whether its the ESCs that I have that are at fault I think.  This is my first brushless build so I don't have any spare ESCs laying around.


Also tested my ZTW Shark units with Futaba and FrSky radio systems to make sure it wasn't me being stupid with the FrSky programming. Futaba is even harsher on startup...

[tsenecal]

i would recommend the castle creations mamba micro x if you expect to run fewer than 35 amps, or the castle creations sidewinder (not sidewinder micro) if you plan on pulling more than 35 amps.

either esc will allow full adjustment of pretty much all aspects of their setup.  using two sidewinders in a 31" dumas UTB 41, i was able to adjust ramp up, max throttle, and apply individual curves so that both prop rpms matched across entire range of throttle stick on transmitter.  the setup was required because i purchased two entry level brushless inrunners that had widely differing performance out of the box...  one esc is set for a max throttle of 57%, other is 63%, but props are both running at 3500 rpm with those settings.

Afternoon / Evening All


Making progress with a flat varnish finish now.  Have resorted to wiping on a 50/50 thinned layer and not brushed...


And several coats, no inclusions, no brushmarks and flatter:








Have been playing with motors and ESC and radio while varnish dries...


And not too happy with the aggressive startup of the brushless motors (Overlander T3530/14).  Seems to me I made a mistake with the cheaper Shark 30A ESCs.  I have the programming card and have tried the various startup options.  Also having some issues getting the two units synced in terms of where they startup.  I have set their end points... Have I missed something obvious..?


Am considering the FrSky Neuron S 40A ESCs as they seem to have a fully programmable interface via PC, so I can guarantee they are both synced.  Also they seem to push back a load of telemetry without extra sensors...  But not cheap...  £50 each...


Any comments gratefully received.
Thanks
David.

[ChrisF]

Hi David

Build is looking beautiful.

I've bought Overlander motors for all my Fairey builds, not ready for water yet, and am probably going to use Leopard Hobby Marine ESCs as they offer good adjustability. It's a pity that Overlander don't do ESCs that can be used in boats.

Chris

[DJW]

Hi All


Thanks for the recommendations, all being looked at and considered.


I'm wanting fine control with the Aquarama setup, seems boats get a small selection of ESCs, and plenty of emphasis on pure power rather than control. Also realising that the lower cost units use a programming card and have limited options, spend more money like the Castle Creations (waterproof..) and FrSky Neuron (not waterproof...) and get a lot of control and telemetry...  I like the idea of getting the various voltages back to the TX, and the temperature of the ESCs, rather than a blue smoke signal...  And as tsenecal mentioned, the sync options when running two motors on two ESCs on two channels, are far more precise throughout the rev range with the higher end ESCs...


I'm not sure about the Leopard Hobby units Chris, have you used them before..?  They don't seem to have adjustable acceleration and that's what I'm wrestling with now.


Andy seems to have a good setup with a good progressive startup. It'll be interesting to see how the Overlander ESC drives the Overlander motor... Once I'm convinced that the motors I have can startup smoothly, I'll decide the ESC route. (These are 14 pole motors, I need to make sure that's not part of the problem with the more modest ESCs.)

[ChrisF]

Hi David

Not used one yet as builds were delayed by not doing the spray painting when the weather was favourable! I was going to use Fusion Hawk ESCs as used in my Huntress with a Turnigy motor which moves off nice and smoothly but it's difficult to get them now.

Component Shop do the Leopard ones and would appear to be good quality and they have USB connection as well as program card which suggests can be programmed via PC as well. Frustratingly very little info. can be obtained by internet searching. The spec. does say that the software designed for RC boats does give excellent start up and acceleration performance.

As you say there isn't  a great choice in ESCs for boats. I'll order one and see how it performs on the bench. My boats are all single motor though so don't need to worry about synching the motors, just want a smooth start.

Chris

[DJW]

Afternoon All


Well I received the loaned out Overlander ESC, and it gives perfect control of the motor.  If only they made a forward / reverse marine version...  So the ZWT Shark ESCs are heading for the bin, or at least a parts draw, I hate throwing parts away...


I've arrived at what I think is now the final varnish coat.  This was wiped on with a 'lint free' cloth, pretty happy with the result:











I've started to look at the upholstery, I've added a fillet into the sundeck to get radiused surface, needs some finishing:





And have started masking and bonding the shafts and P brackets in place:








I've added in a locking collar on the propshaft with a PTFE washer on either side, that collar will transmit the prop thrust to the motor mount, reverse thrust will be similarly applied to the motor mount by the drive gear at the front of the motor mount.





Best regards to all.
David.

[ChrisF]

Hi David

You might as well bin them or give them away as I doubt you will want to use them in anything! The Riva deserves, no demands, to have top notch components!

I said that it was a pity that Overlander don't do a suitable ESC and your test now confirms this but I guess that the market is small than that for aircraft.

I've ordered one of the Leopard ESCs so will see how it performs on the bench. Unfortunately Component Shop are out of program cards so I hope it can be set up via the PC. Hopefully it is good as I need 5 for my current builds and haven't found anything else yet.

Chris

[DJW]

Hi Chris


Agreed re the Sharks...  My nagging doubt is that they may be OK on other motors, the Overlanders I have are 14 pole...  I think that's quite high in brushless terms, the Sharks may work on other motors, or not...


At risk of opening a can of worms...  I got the high pole count versions as I thought / think that it give better low down torque...  But I'm really not sure I made the right decision as I have no real experience with these motors.  I also have the 3:2 reduction gearbox to further reduce the RPM as one of my aims is fine low end control...


Will be interested in the Leopard ESCs if they have a PC interface, I think that's the only way to get full / accurate synchronisation with twin motors.


I need Andy to put his Tug on a shelf and get back to finishing his Riva to see how it goes...  Think he's using the Riva as a door stop at the moment...   


David.

[Taranis]

The tug I can feel is on the downhill stretch now having started the 30 window frames. Detailing the inside of the wheelhouse will be one of the last jobs and then I'll be waiting on the weather to spray the deck and hull in final finishes.
At 34kg it will have to be one heck of a shelf 



I still recommend that you try the Hobbywing Quicrun ESC's at only about £24 I cannot fault them. 30 amp should be more than adequate for your propellers. The motors only draw a fraction of their rated currents.


I bought the bigger 60 amp ones for my tug and its 84mm props only to find that on full power they are only drawing 21 amps tethered in the test tank

[DJW]

Hi Andy


34kg...  That's quite a build..!


After my bad experience with the Shark ESCs, I'm going to get a couple of models to test with as I now realise they are all not equal...  And the Hobbywing will be one of them.


Made some progress today, I have the prop tubes, P brackets and rudder tubes bonded in now:





And this is what the motors look like in place:








A little tidying required around the epoxy and fill a couple of little pinholes:





Will get the water pickups in tomorrow.


I'm thinking to make the whole underwater section white rather than the plan version of the white chevron at the bow.


Best regards to all.
David.