Who wants to build a semi-scale all-wood micro hydro?

[Dr. Jet]

Looking back at this thread, I plan to test the prototype this weekend (weather permitting) after my long hiatus from boating projects. I wish I had the files in 3-D as this scale would be perfect for 3-D printing. Oh well, I suppose it's going to be plywood and balsa as far as I can see into the future.

[Dr. Jet]

Since this is also a two-model production (a Prototype and the final model) I've been building a pair sided-by-side and incorporating the lessons learned on the prototype into the final model. Prices in the Asian market are all over the place, but I just found a real good deal on the motor I selected for the prototype. See http://www.ehirobo.com/copterx-cx450...or-3550kv.html This motor has a 3mm shaft so the Aquacraft GP-1 motor coupler works like a charm. I have to ream out the wire end to 1/16". but that's a no-brainer.

If I run it this weekend, I'll try to take some vids. It may be an over-powered handful with this motor, I'll start with some really small props. I couldn't keep the BBY micro on the water with a similar motor and a 31mm prop; it was much happier with a 29mmx1.6P prop.

[JimClark]

Oh sure you resurrect this thread just after I gave away all of my small couplers and stub shafts.

[Dr. Jet]

Oh sure you resurrect this thread just after I gave away all of my small couplers and stub shafts.

I've designed this around currently available components so you can always "re-stock" your inventory (it's cheap enough).

Never give away the small stuff. There's always room for a micro or two.....

[Dr. Jet]

With the completion of Prototype I of the 16" Cat, I've decided to finish the final version of this hull next in the queue. The prototype Atlas is ready for testing and hopefully, the weather will cooperate next weekend. I'll try to take some vids.

The final version of this hull incorporates a whole bunch of revisions to the laser-cutting plans and building has been a breeze. I'll be finish-shaping and applying the port top skin later today.



The prototype (again ):

[MarkF]

Looks good Bill.

Mark

[Dr. Jet]

Looks good Bill.

Mark

Thanks Mark,

I wasn't quite happy with the shape of the cowl, the final version will be better. This one will get a "Non-Scale" pant job down the line. Maybe I'll do another "Auric Enterprises" since I have extra decals left over from the Micro Scat Cat.....

[Dr. Jet]

Just a little update to keep this thread going. Chris (a.k.a. cjs on this forum) will be getting a prototype kit as soon as the necessary parts arrive and I get around to cutting one. I will be including a motor, a modified GP-1 coupler, parts for my custom 1/32" wire drive, and some other bits as well. I want to do some testing on Prototype I before releasing the kit to the public. I may try to do that tomorrow, weather depending.

Work on Prototype II is progressing. It is currently in the paint shop, but it still needs a lot more filling and sanding before getting the final "scale" paint scheme. I haven't installed the stuffing tube yet, that will have to wait until a new motor arrives. I have several similar motors in my inventory, but for this project, I want to use the same motor in all prototypes. I do not have any photos at this time, but it looks just like Prototype I only somewhat smoother and shinier. I'm trying to decide how to do the scale exhaust, and I think I have a plan. I have already added the necessary parts to the kit drawings. Stay tuned for details.

[Dr. Jet]

Scale Exhaust

OK boys and girls, here's my plan for scale-looking exhaust. Rather than just paint (or stickers) on the outside of the cowl like the GP-1 did, I wanted something that looked more scale. The Merlin engine had 2 exhaust ports per cylinder and the full-sized exhaust stacks were "flattened" at the cylinder head so that the two ports fed into one stack. The flattened stack became round towards the exit and turned sharply upwards. There is no way (other than resin-casting them) that I am going to make twelve perfect miniature stacks in that shape, so I decided to settle for round stacks with a slightly beveled exit. I cut out the elongated hole in the sides of the balsa cowl for the stacks. Then I hollowed-out the inside of the cowl so I can access the the stacks from the inside. All this exposed wood will get coated with epoxy, sanded and filed to a proper shape and dimension as necessary and re-epoxied until everything is the right shape and fully waterproof.

I have drilled six perfectly-spaced and perfectly linear holes in a strip of 3/32" carbon fiber strip with the help of my mill. (The kit will have these laser-cut from 1/16" ply.) I'll glue short pieces of 3/16" aluminum tube into these holes flush with one side of the strip. I'll glue another strip to this flush side to make them water-tight. The other end will get sanded to the correct length and be beveled so that they look exactly right. Finally, I'll glue the cowl to the hatch cover, finish the painting of the model, and when everything is said and done, glue the stacks in place from the inside. I'll smear the inside of the cowl with an epoxy and Cab-O-Sil mix to ensure everything is water-tight.

[Dr. Jet]

I didn't have any 3/16" aluminum tube in my drawer of round stuff, but I did have 3/16" styrene tube. Behold! Exhaust stacks.
.

[JimClark]

I bet Jim Stevens up here could just scale his files down and print them for you

[Dr. Jet]

I bet Jim Stevens up here could just scale his files down and print them for you

Files of what???

[JimClark]

3d printing of motor parts like stacks. There are actually two guys up in the PNW who are making scale hydro motor parts that look way better than anything that has been available in the past.

Sent from my Moto G (4) using Tapatalk

[Dr. Jet]

3d printing of motor parts like stacks. There are actually two guys up in the PNW who are making scale hydro motor parts that look way better than anything that has been available in the past.

Sent from my Moto G (4) using Tapatalk

Give me a way to contact them. I'd love to have 1/20 scale engines and drivers.

[JimClark]

here you go

Jim Stevens

https://www.scale-3d.com/?fbclid=IwAR1AzEwwaciowYGL7YrMkkGVMogcaTA6z6TPivDycaH4WkZf6EpNh1F4zv4

Craig Mullen

https://www.spartacusboatworks.com/?fbclid=IwAR0ScIZLgb7KuFY8sNmy-lC4x-2Zail0rsxUjQCnhRYyBGYAWFc-PpUBd2o