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Author Topic: 1/5 Riva Aquarama...  (Read 64295 times)

ChrisF

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Re: 1/5 Riva Aquarama...
« Reply #125 on: November 09, 2022, 04:10:32 pm »

What can one say!   :-))
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Building Fairey Marine boats: Faun 17, River Cruiser 23 prototype, Huntress 23 Long Cabin with stern-drive, Fisherman 27, Huntsman 28, Huntsman 31 and Swordsman 33. All scratch built and to a scale of 1:12

SteamboatPhil

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Re: 1/5 Riva Aquarama...
« Reply #126 on: November 09, 2022, 06:33:54 pm »

Gobsmacked......absolutely brilliant..  :-))
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Stuw

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Re: 1/5 Riva Aquarama...
« Reply #127 on: November 09, 2022, 10:09:49 pm »

 :-)) %%
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2 Lesro Javelins... and that’s it. Not even close to finished!

DJW

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Re: 1/5 Riva Aquarama...
« Reply #128 on: November 11, 2022, 05:39:39 pm »

Thanks Chaps, just hoping it all works out...


A quick update.  I knew cutting out the aluminium for the motor mounts would be arduous, and it is.


Early days, the channel has been cut and marked up:








Had to remove the usual clamp and just bolt the mount to the mill to accommodate it...  Then started to get the edges square, and then used a small mill bit to start to cut out the interior, want to get good square cuts if I can and rounded corners.








If I can get one mount cut from the channel, drilled and trimmed this weekend I'll be happy.


Best regards to all.
David.

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DJW

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Re: 1/5 Riva Aquarama...
« Reply #129 on: November 14, 2022, 06:22:11 pm »

Evening All


Took a bit longer with the first motor mount than I'd anticipated. But it's now its pretty much ready.





And here with a motor in place.





And with a shaft ready to attach.



Next is either make another mount, or carry on and create the water cooling plate, currently a 3d plastic template in the pics above....


It's nice to see the mount coming together in aluminium. Feels like progress.


Regards to all.
David.
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Capt Podge

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Re: 1/5 Riva Aquarama...
« Reply #130 on: November 14, 2022, 07:51:54 pm »

That's a fine and solid looking bit of work you have done there David - great work with it so far  :-))


Ray.
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T888

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Re: 1/5 Riva Aquarama...
« Reply #131 on: November 15, 2022, 03:33:31 pm »

Nice bit of milling  :-))
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DJW

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Re: 1/5 Riva Aquarama...
« Reply #132 on: November 15, 2022, 09:17:58 pm »

Thanks Both. A couple of hours today starting to fabricate the motor mount plates. 8mm aluminium plate cut to 80x50mm x 2.



Then edges milled to get everything square, nice finish and final sizing.



Then a 2mm plate same size, and drilled out using 3d printed template again for the hole positions.


So now at 10mm thick. And tomorrow will be milling out some water cooling channels.





Best regards to all.
David.
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DJW

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Re: 1/5 Riva Aquarama...
« Reply #133 on: November 19, 2022, 05:20:23 pm »

Afternoon All


Well it's been a bit of a week. On the downside. Felt a bit rough, but Wednesday I didn't have Covid, then another test on Thursday and it seems I do have Covid. No idea how I got it. On the upside... Any going out plans cancelled and did get a few hours of building in today and hopefully more tomorrow...


The mounting plates are coming along nicely. First one is fully machined. This is the water inlet and outlet.



And then routed around the plate.

Not my finest work. But I think its accurate enough to be functional.


So here's the plate in situ with motor, and main mount.






I'm pleased that the mounting system is rigid now it's in aluminium.


So next it's complete the second set...


And as the plates are two part, they have to be joined and sealed. My current plan is to use an approach I used back in the day using Araldite Rapid and an oven. I heat the aluminium in the oven to about 50 ish degrees, then apply the mixed epoxy, it's viscosity reduces and it flows really well, I think this helps it bond even better with the aluminium. Anyway its worked for me in the past with aluminium so I'll give it a go. Once cooled, the epoxy is fully flowed and very hard so should fully seal the mount plate.


Best regards to all.
David.
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Capt Podge

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Re: 1/5 Riva Aquarama...
« Reply #134 on: November 19, 2022, 05:43:06 pm »

Sorry to hear you've been 'under the weather' David but good to see you're still able to get a bit more done and your explanation of how to achieve the seal sounds very interesting.
Hope it all goes well for you.


Ray.
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ChrisF

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Re: 1/5 Riva Aquarama...
« Reply #135 on: November 19, 2022, 06:04:18 pm »

A work of art - as usual!

Chris
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Building Fairey Marine boats: Faun 17, River Cruiser 23 prototype, Huntress 23 Long Cabin with stern-drive, Fisherman 27, Huntsman 28, Huntsman 31 and Swordsman 33. All scratch built and to a scale of 1:12

DJW

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Re: 1/5 Riva Aquarama...
« Reply #136 on: November 21, 2022, 08:08:46 pm »

Managed some time today with the 3D Printer. Tweaked the cups on the bobbins so they come in from both ends of the bobbin rather than one. Looks a bit more balanced. Also slightly thinner walls and bevelled open ends to avoid chafing the bobbins.


Old versions.



And the new versions.



And as I'm in a covid induced (wife assisted) absence from my workshop... I've started to consider a kali type of coupling customised for my needs and optimised for the mount. Initial designs in PLA then once I've figured out dimensions I think I can make the ends in aluminium and the centre from TPU filament, should be strong but flexible enough to work well transmitting power through the coupling.






Work in progress...
David.
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Mark T

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Re: 1/5 Riva Aquarama...
« Reply #137 on: November 22, 2022, 04:09:04 pm »

Lovely work you must have made some serious swarf getting that done!

DJW

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Re: 1/5 Riva Aquarama...
« Reply #138 on: January 01, 2023, 03:32:13 pm »

Hey Mark, yes. Did make a bit of a mess, at least with the metal bits it doesn't produce the dust like wood... I have that yet to come...!

Been a bit busy over past month with life in general but finally some progress to report.

I now have the two motor mounts complete in aluminium. Plus the thrust assemblies drilled, threaded and attached to the mounts. Same with the prop tubes.







That last pic also has prototype coupling in view.  3D printed at this stage.

Finally. Added the oiling tubes to the prop tubes.



Need to check alignment then start to create the couplings in aluminium.
Best regards to all
David.
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1/10th Aquarama Build - https://tinyurl.com/riva-aquarama
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Mark T

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Re: 1/5 Riva Aquarama...
« Reply #139 on: January 01, 2023, 08:43:52 pm »

Wow I am literally finding the engineering going into this build astounding  - I'm lost for words its that good  :-))   Keep the updates coming please!

derekwarner

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Re: 1/5 Riva Aquarama...
« Reply #140 on: January 02, 2023, 03:00:48 am »


Morning David........I have followed this [and the previous] build with great interest, especially with the drive lines


With the current [1/5 scale] build, I see you appear to using a single 3 element ball thrust race in each drive shaft, however I am a little confused as am unsure if this trust race is used in two locations in differing housings within each drive shaft?


Reading about brushless motors [in-runner and out-runner styles], however I found little if any talk about the need for any additional consideration of driveline thrust :-X


May I ask, did you attempt to establish a calculation of distance to limit directional resultant thrust, or just pick a number [say 0.005"] of permissible directional limit thrust element movement?


Derek
 
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Derek Warner

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DJW

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Re: 1/5 Riva Aquarama...
« Reply #141 on: January 02, 2023, 09:47:27 am »

Morning Derek, thanks for the feedback, hope all's well with you.


Each drive line will indeed use two thrust races, one for forward thrust and one for reverse.  They will both pass their thrust forces to the motor mount.  Inside what I'm calling the 'thrust assembly' is a collar that can be locked onto the propshaft with one of the thrust bearings between the that collar and the main motor mount. Then as long as there's a little clearance between prop and P Bracket, that bearing should take forward thrust.  The second thrust bearing is going motor side as the propshaft passes through the motor mount, between the motor mount and the coupling, that will take reverse thrust and again apply it to the motor mount.  Hope that makes sense, I'll get some better pictures to illustrate.  The couplings will allow a small longitudinal movement, but it will be minimal once adjusted.


And as to why do it at all...  Well, I think it's all resulting from wanting to isolate the motors from the hull to reduce transmitted sound / whine to the hull.  Once I decided to use rubber mounts, that means the motors can move if sufficient force is applied to them, and as they're rated at 1,600w, that could get messy...  So I felt the only way was to then remove that thrust force from the motors altogether, and this is my solution.  I do agree that the motors should be able to take any longitudinal forces they generate via their shaft bearings, but in my head that force transmitted through the motor itself via ball races (not full on thrust bearings) is not ideal.  Just my view...  So all these motors should have to do is spin, all forces generated by them will be absorbed (or damped) elsewhere, that's the aim.  I also wanted to build the driveline in one assembly rather than rely on the hull itself for alignment.  It's going to be a large wooden hull after all that may flex.


As always, we'll all have to wait to see if all the effort is worthwhile..!
Very best regards and a Happy New Year to all.
David.
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DJW

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Re: 1/5 Riva Aquarama...
« Reply #142 on: January 02, 2023, 08:01:12 pm »

Hi Derek

Just found these earlier images, I was checking the fit of the thrust bearings in the housing.

This shows the motor end of the thrust assembly at the point it mates with the motor mount.



The hole is 7mm, to take the 5mm propshaft.

Then the assembly holds one thrust bearing on each side.





The collar and the coupling are machined to keep the thrust bearings centralised.

Best regards
David.
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Martin (Admin)

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Re: 1/5 Riva Aquarama...
« Reply #143 on: January 02, 2023, 08:36:28 pm »

 
Beats my plastic I found in an old tool box ....  %)
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derekwarner

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Re: 1/5 Riva Aquarama...
« Reply #144 on: January 03, 2023, 08:48:25 am »

Thanks David


I now understand the concept set for the thrust group for each of your drive lines

Have ordered a dual set of AYX0619 [6mm x 19mm] caged needle roller components
The challenge I have is to contain, or restrict longitudinal movement in a Y2DR steam engine crankshaft
The engine has one spare 20mm space between journals, so hope to fabricate a housing to contain the trust components

regards Derek
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Derek Warner

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DJW

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Re: 1/5 Riva Aquarama...
« Reply #145 on: January 03, 2023, 08:26:08 pm »

Hi Derek
I guess this comes down to what fabrication tools you have available, do you have a thread running on the forum here documenting the project..?


I find it a challenge (that I enjoy most of the time...) to create the parts I need with the modest machine tools that I have.  I have to plan well ahead so I don't conceive something that i then can't fabricate. Access to a machine shop and the skills to go with it would make life easier..!!!
David.
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DJW

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Re: 1/5 Riva Aquarama...
« Reply #146 on: January 18, 2023, 10:04:25 am »

Morning All

Not had very much time to spend on the build recently, very frustrating...

Some modest progress to report on the drivelines.  I've been playing with 3D printed versions of the couplings required with the aim of seeing what dimensions work. Also to make sure it can all be actually assembled when in the boat, so for instance be able to replace the centre of the coupling without a full motor removal.  But now moving to the aluminium fabrication stage.  Motor end first, this (in black plastic) is an idea of what I'm aiming for in terms of machining the lugs, and next to it an aluminium blank.


And then a couple of jigs to hold the blanks for machining and to act as guides.  (Santa didn't bring a CNC mill...) The guides will be sacrificial for the final stage of machining, so printed one per coupling end. 



The holes in the jigs at the base are drill guides for the eventual use of grub screws that will lock the coupling to the shaft, and while in the jig will have bolts inserted to keep everything rigid while clamped in the mill.
I've then got the coupling centres printed in (a rather attractive lime green...) TPU, a more flexible filament than the standard PLA printing material.
This shows where the initial slots will be milled out, 3mm...


I'm working on the coupling blanks for the prop shaft end now (and for a shiny new 3mm mill cutter to arrive), they're a little different as they need to centre the (reverse) thrust bearing.  So the coupling section that has the grub screw will be a little larger in diameter (16mm, same as the thrust bearing) and have a small shoulder on the thrust bearing end to locate the bearing and centre it.

What could possibly go wrong..??!!
David.
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SteamboatPhil

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Re: 1/5 Riva Aquarama...
« Reply #147 on: January 18, 2023, 03:19:02 pm »

Beautiful engineering such a pity it all gets hidden the boat  :D
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DJW

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Re: 1/5 Riva Aquarama...
« Reply #148 on: January 19, 2023, 11:10:17 am »

Hi Phil, thanks..!  And assuming this ever materialises into a viable boat, we'll know it's there..!


Best regards
David.
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SteamboatPhil

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Re: 1/5 Riva Aquarama...
« Reply #149 on: January 19, 2023, 03:18:10 pm »

 :-))
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