BBY Micro Turbine Hydro for SSSH

[Sneasle]

Are you talking about the SC or the Hydro?

How many layers do you think I need? Would it be better to use a denser cloth? I'm just trying to be the most cost conscious, this stuff isn't cheap..

[Dr. Jet]

I was talking about the Micro Turbine Hydro, but it would be the same for the SC, I would think. Nah, don't bother with the heavier stuff. This may be better for small hulls in the long run. The stuff that is most common is 5.7 oz., and it is overkill for these little hulls. The veil might be a better choice for weight concerns as you can use a lot less epoxy. I'd do like 4 to 6 layers (total) under the motor mount and two or three for the rest of the hull.

Paint the inside of hull with epoxy (a very thin layer), put down one layer of veil, and work epoxy into it with a small (1") paintbrush. When it is wetted out, dab it dry with a paper towel (less epoxy is better), lay down another layer, and wet it out with the brush, and dab with the paper towel. Keep doing this until you have what looks like enough veil layed down. Then add more smaller pieces to the motor mount area.

Never use hobby shop epoxy. That stuff is for emergency field repairs only. Use the 4:1 stuff from DMC or West Systems.

[Sneasle]

Kk.

what do you use for brushes? I can imagine they don't get reused easily.

edit:

what about epoxy resin sold at auto shops, is that useable?

[Dr. Jet]

I buy those really cheap 1" brushes at Home Depot. They are somewhere around 50¢ to 99¢ each. No, I don't re-use them (unless I need a chisel).

I don't know about the auto store epoxy, I never used it. There may be a reason for that.

[Sneasle]

KK.

It is an epoxy resin used when doing fiberglass autobody work, so I would assume the quality is reasonable...

[Dr. Jet]

You want an epoxy that is thin, so it can wet-out the fabric with minimal weight, and slow to set so you have time to work with it.

Call DMC and order the good stuff. You will be glad you did. Trust me.

[Sneasle]

You want an epoxy that is thin, so it can wet-out the fabric with minimal weight, and slow to set so you have time to work with it.

Call DMC and order the good stuff. You will be glad you did. Trust me.

How much is it?

Remember, this is supposed to be a cheap boat. If i drop $50 for CF and another $50 for epoxy, it isn't so cheap anymore.

I was planning on just thinning down the resin with alcohol.

[Dr. Jet]

It's not that cheap, but it's not exorbitantly priced either. Just remember, you get a lifetime supply that you can amortize over dozens of projects. I usually get a quart of epoxy and a pint of hardner. Just remember to mix carefully. I use a triple-beam scale to weigh out larger amounts, or just mix 4 drops (or multiples of 4) of epoxy to 1 drop (or multiples of 1) of hardner (warm the hardner so it's thin like the epoxy).

[Sneasle]

not that cheap as in, not $50 cheap?

damn.....


hmm... time for plan c.

[Dr. Jet]

It has been a LOOOOOOONG time since I bought epoxy. I don't remember the price. Give them a call and see what it is.

[Dr. Jet]

I've been a bit remiss on this project for a while; a few other things got in the way.

I'm going to try another $25 ebay outrunner/ESC combo on this one, just because. Here's a link to the motor I will use. http://cgi.ebay.com/ws/eBayISAPI.dll...%3D4%26ps%3D42. Note that this seller usually has a higher buy it now price than the 3000 Kv motor from cyberport888, but if you look long enough, you can find an auction with a low bid price. I had to watch several auctions to get a $25 (including shipping) price.

This motor has a higher Kv and a cooling fan, so I thought I would give it a go. The BBY hull I'm building this time will not be for SSSH class racing; instead, it is just going to be a "fun runner" like my MHZ Miss Madison (and my new "Secret Project X-9").

There may be a micro rescue boat (MRB) that cuts in front of this build so there may be another slight delay. Building the MRB will be quick and dirty so any delay will be minimal.

[peells]

So D.J. How well do the ESC's work with a P.G. type radio? I have had them start up just after power up with out touching the trigger, and when I pulled the trigger it would stop, and when I pushed the trigger it was like kicking in the turbo have you had this problem?

[Dr. Jet]

With the Mystery controllers I get from cyberport888 (yellow wrapper and 2 capacitors), they work just fine. The ones in the blue wrapper have been less than successful. The one I received with this motor/ESC combo looks different than the other blue ones I have seen (it has 2 capacitors as opposed to 1). I will let you know when I hook everything up. I already have a yellow wrapped one that has been waterproofed, so I think that one will wind up in this hull, but I will try out the blue one just to report back to you guys.

[Sneasle]

.

I've been wondering if you had fallen in or something.....

I've been putting mine on hold as well.... and I just got a heli... soo.......



Question: would FG cloth be ok to reinforce the bottom? Tis much cheaper then CF.

I need to get my rudder and TF ordered from joe..... What servo's did ya'll say you were using for the rudder?

[Dr. Jet]

FG will be as good as CF, just add an extra layer or two in the motor area. I used the CF because I had a bunch of it. I only have a few scraps left now…..

I used a CS 20 in Prototype 1, simply because I had one lying around. I bought a half-dozen 9-gram servos on ebay for about $5 each, and one of them will go into Prototype 2.

[Sneasle]

good to know. I'll look and see what I can find.

I assume there is a weight penalty with FG as well, I just wonder how significant.


edit:

what size packs are you running on this? 2s, 3s, capacity?

[Dr. Jet]

I'm using 2S packs of 1300 to 1900 mah.

[JimClark]

Hey Doc I got my motor esc combo but was wonderign about programming the ESC to get it to work with a wheel radio. Any tips on programming?

Jim

[Dr. Jet]

If you have the yellow ESC, no programming is necessasy. Plug 'n Play.

[Sneasle]

Can someone give me the dimension of Joe's rudder?

Is a 7cm rudder too long for the hydro?

[J Solinger]

I have put up the overall dimensions on my web site. Click on "Micro Hardware" then click on the photo.

[Sneasle]

Cool, thanks Joe.

can I order from you off the site or do I just need to pm you when I am ready?

[J Solinger]

Just send a pm when your ready.

[RandyatBBY]

Well the little MTH just Bumped the record 14MPH to 48 Miles per hour and some change. God job Wilmer! That is flying in a little 15 inch boat1

[Sneasle]

Well the little MTH just Bumped the record 14MPH to 48 Miles per hour and some change. God job Wilmer! That is flying in a little 15 inch boat1

say what?


dare I ask what was running in that boat to get this little hull to 48?

[RandyatBBY]

A 19t stock motor and 8 Nimh cells.

[Sneasle]

that doesn't sound all that hard to do.

Hmm... I wonder if this hull can break 60 easily....

[RandyatBBY]

Hard? Will has been testing this hull for a year I have been giving him tips and he has some real creative ideas. It would be easyer with brushless ie big motor High KV, three cell and real smooth water.

[Sneasle]

I just meant that the motor/batt combo didn't sound very challenging to put together. Nothing in '19t stock with 8cell nimh' sounds all that special.

If there is something special (ie, weird thrust angles or some strange cg stuff), then I would love to hear about it.

If there are some specific numbers that went into how that boat was built, please share them.

[Dr. Jet]

Wilmer has a "modicum" of experience with these little car motors. I'm willing to bet he managed to "tweak" it just a little bit. Furthermore he has been known to make many different small boats perforem quite well. You can rest assured he probably didn't do 48 mph on the first, second, or even third outing. He works hard to get results few others can match.

As for doing 60 with this hull, it may be possible on 3S with something like a small NeuMotor.

As for my build, I think I may sacrifice speed for style on this one. I have joined the hull/deck and shaved the lip off. Currently, I am sharpening and truing all the surfaces on it. I'm using epoxy/ Cab-O-Sil for the building up of the edges, so it takes a day just to apply one layer; a day to sand it; another day for another layer; and so on. It will be a while before it is ready.

Like I said earlier, I have decided to try a different (but still under $25) outrunner/ESC combo to see if it has a bit more "zip." Photos will follow when I have something interesting to show.