1/8th Scale Miss Thriftway Setup

[SeattleRCSailor]

Hi everyone,

I've been building RC sailboats for years, but am now trying my first 1/8th scale hydro... the ML Boatworks 105A Miss Thriftway.

Would very much appreciate advice on the following setup for this boat. Is it appropriate? Would it work? Do the motor and ESC match well enough? I'm only hoping to get around the course without embarrassing myself... not into high-end racing. The picture is a screenshot of my Excel workbook that I'm using to track the order.

Hydro purchases.JPG

I'm especially concerned about which motor setup to use. I'm told the Nue 1527 is great, but do I get the 5mm shaft or 8mm? 850KV? 2500KV? Help!

Any help you can offer is appreciated. Thanks!

Steve

[30nitro]

Oh boy....no need for that motor...if not Racing.....5mm shaft is fine for your application......The specs you have are a little more than you need....I'm sure some one will chime in on a better setup...

[SeattleRCSailor]

30Nitro... thanks!

As I understand it, here in Seattle, the largest group actually races 1/7th scale boats. My thought was that I would make this 1/8th scale boat and really go to school on it. Then I'd build a 1/7th boat and would probably cannibalize the motor and ESC from this current boat. Would this setup be appropriate for a 1/7th scale boat?

Otherwise, do you have suggestions for a motor/ESC pairing that would be better?

Thanks again!

Steve

[30nitro]

Give me some more specs on the boat....you can also search the forums for a vast amount of info....

[SeattleRCSailor]

It's a 1/8th scale hydroplane. About 45" LOA. Wood. Laser cut frames. Shovel nose. Not sure what it will weigh when done... 20 lbs?

[JimClark]

There are clubs that race 1/8th scale
http://www.rcunlimiteds.com/ also http://www.unlimitedsnw.org/

[785boats]

Steve.
There are a couple of problems with your list.

You have listed the 1/4" flex with 3/16" stepdown for the prop. Good choice. But the .21 strut, you have listed, is only 3/16". You need the Speedmaster 1/4 " strut if you are using the 1/4" flex shaft.

Parallel edge rudders work better on Hydros than tapered rudders. And you won't want the long extension bracket.
To comply with the rules for 1/8 scale racing, the drive dog must be under the boat on your model. That means that the strut must be mounted through the floor of the hull in front of the transom. That means that the prop is only just behind the transom. So the rudder should be as close to the transom as possible.

With the 1/4" shaft you need 5/16" tubing with no teflon liner, or 11/32" tubing with teflon liner. Not 1/4" tubing, as you have listed.

It looks like you intend on running 8s, judging by your choice of ESC.
I have the 1527 1250kv motor on 8s in my U-95 model. But I have a Swordfish 240A ESC.
The 850kv version on 10s is probably a better option.

I'm sure others will offer more suggestions soon.

Cheers.
Paul.

[SeattleRCSailor]

Paul, Thank you! That is just the kind of help I was hoping for.

I will make the changes for the flex shaft and strut. And I'll go with the rudder you suggest. Regarding the tubing, do you suggest teflon or no teflon?

However, the 1 5/8" extension on the rudder is exactly what ML Boatworks suggests. So now I'm confused.

I'm also confused on the batteries because I thought the 1/8 rules limits the batteries to 8S, and that the motor was supposed to be 1.5 Y 850KV. Am I wrong? Confused here too.

Thank again for putting up with my ignorance!

Steve

[785boats]

Steve.
Sorry for the confusion on the rudder. For some reason I read it as 2-5/8. Should wear my glasses more often. The 1-5/8 will be ok.
This is the one I use on my 1/8 scales with the 1-1/8 bracket.

https://www.offshoreelectrics.com/pr...d=ros-spdr-012

I was under the impression that you guys could run 10s for 1/8 scale. Here in Australia we can run up to 12s
hopefully, someone on this forum can clarify the voltage for you.

I prefer teflon liners myself, but there are many who prefer not to use them.

Cheers.
Paul.

[leonard feeback]

Steve, before buying a lot of items you may not need or will not work for the built. Go to a couple of the races where the boat are running, ask questions take pictures.
Leonard

[eric113]

Paul, Thank you! That is just the kind of help I was hoping for.

I will make the changes for the flex shaft and strut. And I'll go with the rudder you suggest. Regarding the tubing, do you suggest teflon or no teflon?

However, the 1 5/8" extension on the rudder is exactly what ML Boatworks suggests. So now I'm confused.

I'm also confused on the batteries because I thought the 1/8 rules limits the batteries to 8S, and that the motor was supposed to be 1.5 Y 850KV. Am I wrong? Confused here too.

Thank again for putting up with my ignorance!

Steve

For battery is up to 8s no more than 6000mah per pack and up to 65c rating.
Motor 3 motors to choose from Neu,H.E.T.,hobby king.

[785boats]

I'm pretty sure NAMBA states that 1/8 scale power requirements are for 'T' class with voltages up to 42.3v, which is 10s, & up to 12000mah

Will you be racing under different rules?

[raptor347]

He's hoping the 1/8 scale rule proposal passes. Currently it's T power.

If the rule passes it will be 8S, 6000 mah max capacity, 65C max discharge rate, 57mm max prop diameter, 3 motor options.

P-ltd on a grand scale with all the good and bad parts.

[785boats]

Thanks Brian.
I didn't realise you guys were changing the rules. Fun times. Especially when it seems that most people on these forums have good solid 10s setups already.
And only 6000mah capacity too. That's a big change.

Steve.
I race two of my 1/8 scale hydros with 8s setups.
You will need to drop your prop size in your list from 60mm down to 57mm max by the looks of it.

[raptor347]

The rule change is up for a vote right now. If the rule passes it will obsolete a lot of existing boats. We'll find out may 5th.

[eric113]

I would like to see 8th scale hydros aleast on T class rules.

I also should stated in my previous reply that also rules i posted is for the 8th scale unlimited rules too.

[SeattleRCSailor]

Thanks everyone! Lots of good information.

I went to the local 1/7th scale races this weekend in Monroe, WA. Yes, I said 1/7th scale. That's what's raced up here. I chatted with several people and learned a great deal. I now have a much better list and my OSE order will arrive next week.

I'm outfitting my 1/8th scale boat according to their rules because this 1/8th scale boat is not intended to be raced. It's for me to learn with, and to get some experience. And then I will build a 1/7th scale boat using the same setup.

They have four motors to pick from, but everyone runs the Turnigy SK3 Fandrive 3994 850kv. So that's what I'm putting in my boat.

I've ordered two 5000mAh 4S 70C batteries from OSE, so I hope that they allow up to 70C! I saw several batteries with 70C rating, so I'm assuming it's ok.

Thanks again!

Steve

[SeattleRCSailor]

At the risk of finding out that I've spent an inordinate amount of money on the wrong stuff, here is my much more updated list of stuff for my 1/7th scale hydro build (yes, it's actually 1/8th scale, but I'm only practicing for my future 1/7th build).

Hydro purchases.jpg

Yes, I know that some of the parts are not what most 1/8th scale boats would use, but again, I'm trying to conform to the 1/7th rules. They require that specific prop, that motor, those batteries. Most of the other stuff is to simply make those things work together. So I hope it all works!

Thanks again for all the great advice. Much of your advice is reflected in this order.

Steve