SB-90 1/10 Scale

This is the building forum for the Combat Boat 90. If you are interested in the STL's for this project, they are available to those who help me by contributing 15 Euro. Then you get access to a sub-forum where STL's, instructions and mods are located.
admin
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Re: SB-90 1/10 Scale

Postby admin » Mon Aug 13, 2018 7:44 am

Matsa wrote:
Sat Aug 11, 2018 2:11 am
But still i try making parts on deck and above more lightweight, because i think its better to add weight
at the bottom of the hull then above it ofcourse.
Yes, I would put some serious reinforcements in the hull, especially under the water line. A couple of strips of fiberglass along the keel and fiberglass cloth along the hull sides as well so you don't get a print layer crack if you hit something.
This also reminds me of a to-do, I have to take care of CAD'ing the rubber dampers for the hull edges now. Was thinking of printing them in flex, that would be cool! (Or printing moulds to make rubber casting). But these dampers would really be useful on such a big model if you run into something, not just for cosmetics.

Matsa
Posts: 32
Joined: Tue May 22, 2018 10:46 am

Re: SB-90 1/10 Scale

Postby Matsa » Wed Aug 15, 2018 4:27 am

Hi Gary.

I'm using the BL4 Engine on this webpage:
http://www.prestwich.ndirect.co.uk/brushless.htm

I will not use a cooling pump at all, i will fit a 4mm brasstube intoo the nozzle slightly aimed
against the waterflow.
Like this:
Image

Matsa...

nitewatchman wrote:
Mon Aug 13, 2018 5:34 am
Out of sheer curiosity, what engines are you using?

I am thinking of a 1/12th or 1/15th scale boat. I have delta printers and the biggest is 300mm diameter and 550mm tall. The outer is slightly smaller at 280 mm and 400mm tall.

Also what do you have in mind for cooling pumps?

gary

Matsa
Posts: 32
Joined: Tue May 22, 2018 10:46 am

Re: SB-90 1/10 Scale

Postby Matsa » Wed Aug 15, 2018 4:31 am

Yes i will use glassfiber strips and laminating epoxy to cover the joints inside the hull.
Hmmm will epoxy stick good to the PLA? Maybe i should do a test first :lol:

Matsa...

admin wrote:
Mon Aug 13, 2018 7:44 am
Matsa wrote:
Sat Aug 11, 2018 2:11 am
But still i try making parts on deck and above more lightweight, because i think its better to add weight
at the bottom of the hull then above it ofcourse.
Yes, I would put some serious reinforcements in the hull, especially under the water line. A couple of strips of fiberglass along the keel and fiberglass cloth along the hull sides as well so you don't get a print layer crack if you hit something.
This also reminds me of a to-do, I have to take care of CAD'ing the rubber dampers for the hull edges now. Was thinking of printing them in flex, that would be cool! (Or printing moulds to make rubber casting). But these dampers would really be useful on such a big model if you run into something, not just for cosmetics.

Matsa
Posts: 32
Joined: Tue May 22, 2018 10:46 am

Re: SB-90 1/10 Scale

Postby Matsa » Wed Aug 15, 2018 5:43 am

A little progress.

Been printing the hatches for my SB90
Image

Good to have if it sinks lol
Image

I made some reinforcements were the screws otherwise
will tear on the plastic using 4mm brasstube.
Image

Impeller with axel balanced in one piece with the Du-Bro propeller balancer för RC planes.
Image

Matsa...

admin
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Posts: 430
Joined: Thu Jan 11, 2018 7:46 pm

Re: SB-90 1/10 Scale

Postby admin » Wed Aug 15, 2018 7:39 am

haha!! that 4mm brass tube looks tiny! I simply cannot wait to see this monster in action! You will get some serious thrust through the shaft , do you plan to let the motor bearings take the axial load? I'm pretty sure they can cope, but it might be good to think about this because if any 3d-printed part would take that axial force through a bushing or something that rotates, you could end up with a friction-melted mess. Given this, I think it's good the way you've done the motor mounts so you can transfer the thrust through those to the hull.

Matsa
Posts: 32
Joined: Tue May 22, 2018 10:46 am

Re: SB-90 1/10 Scale

Postby Matsa » Fri Aug 17, 2018 12:10 pm

admin wrote:
Wed Aug 15, 2018 7:39 am
haha!! that 4mm brass tube looks tiny! I simply cannot wait to see this monster in action! You will get some serious thrust through the shaft , do you plan to let the motor bearings take the axial load? I'm pretty sure they can cope, but it might be good to think about this because if any 3d-printed part would take that axial force through a bushing or something that rotates, you could end up with a friction-melted mess. Given this, I think it's good the way you've done the motor mounts so you can transfer the thrust through those to the hull.
Yes its pretty big :lol:
I will mount it so it doesent grind together with the flat spot inside the exit nozzle.

Matsa...

Matsa
Posts: 32
Joined: Tue May 22, 2018 10:46 am

Re: SB-90 1/10 Scale

Postby Matsa » Fri Aug 17, 2018 12:15 pm

A few more updates.

Started to reinforce the joints in the hull with glass fiber and laminating epoxy.
Image

Heated up a brasstube so it could be bent in a nice curve for the watercooling.
Engines and ESC's is watercooled so i hope i get enough pressure for it.
Image

Matsa...

admin
Site Admin
Posts: 430
Joined: Thu Jan 11, 2018 7:46 pm

Re: SB-90 1/10 Scale

Postby admin » Tue Aug 21, 2018 9:40 pm

I noticed one thing, both the impeller and the stators are left with "thick" edges to be possible to print without too warping and other issues, and at your scale that is very much visible.

To get the best performance from your water jets, I strongly suggest you sand at least the leading edge of the impeller blades. Maybe it's not critical for the guide vane stator blades, but probably they could do with some smoothing also.

I know you've already balanced your impellers, but if it's not too much job to re-balance, I really think you should smoothen the leading edge of the blades. You will most likely get noticeable increase in performance.

Matsa
Posts: 32
Joined: Tue May 22, 2018 10:46 am

Re: SB-90 1/10 Scale

Postby Matsa » Sun Aug 26, 2018 12:47 am

admin wrote:
Tue Aug 21, 2018 9:40 pm
I noticed one thing, both the impeller and the stators are left with "thick" edges to be possible to print without too warping and other issues, and at your scale that is very much visible.

To get the best performance from your water jets, I strongly suggest you sand at least the leading edge of the impeller blades. Maybe it's not critical for the guide vane stator blades, but probably they could do with some smoothing also.

I know you've already balanced your impellers, but if it's not too much job to re-balance, I really think you should smoothen the leading edge of the blades. You will most likely get noticeable increase in performance.

Its funny you thinked about it because i sanded the edges and balanced then painted them before i saw this message :lol:

Image

I also started to notice my 3D printer printed everything crooked from half the buildarea and furter back.
Now i saw that one of the X,Y-belts is very stretchy at a 10cm point so i guess some reinforcements inside the belt broken.

New belts are ordered and should arrive at Tuesday, those are glassfiber reinforced.

Matsa...

admin
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Posts: 430
Joined: Thu Jan 11, 2018 7:46 pm

Re: SB-90 1/10 Scale

Postby admin » Mon Aug 27, 2018 7:54 pm

Looking good! :)


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