Super Hawaii Brushless Build. Can I ask a few questions?

**Simon170** · 05-08-2014, 09:44 AM

I looked at doing this to my Gancia Dei Gancia (basically the same boat) but was talked out of it when I was told how much hull strengthening work would be needed.
Also what voltage are planning on using?

**CKoz** · 05-08-2014, 10:15 AM

11.1 volts. This puts the proposed setup at 25,086 rpm. Shoring up the hull is not that difficult. Theres some videos out there already. I have a 40 watt laser at my disposal. I'm planning on gluing in thin acrylic panels in the critical areas. Plus I just cruise on glass waters anyway...

**Mad_Props** · 05-08-2014, 11:01 AM

I think I had my eye on this boat, ebay? Subscribed for the mods, always wanted one of these hulls!

**CKoz** · 05-08-2014, 11:26 AM

I kind of got taken on it a bit. Paid $175. Came with a nice Tekin marine ESC, 2 stock motors, 2 mod 550's of which one was dead. good news is that the hull is in excellent shape and the out drive is excellent... What do you think about the motor and esc combo? will it work?

**Mad_Props** · 05-08-2014, 12:06 PM

Gotcha, I always oogled the Cesa 1882 at my local hobby shop when I was younger, ended up picking the MRP Miss Budweiser from that era up, still can't get the damn thing on plane. No pun, but I'm in the same boat... I'm not too aware about all this new FE stuff and it kida confuses me. However, I found this link that kind of explains things a little better on the brushless/lipo scene... http://www.radiocontrolinfo.com/RCca....php#Brushless

What I was going to do with mine is purchase a setup from a proven boat around that size, I'm not fond of dumping a million dollars in a 20 dollar hull, so to speak, but then again, I am also a cheapass, lol...

**CKoz** · 05-08-2014, 07:15 PM

Well, thanks for the chat Mad_Props and Simon. It doesn't look like my project rates an opinion from the experts so I'm gonna go ahead and stick with my formula. Take care.

**gsbuickman** · 05-09-2014, 01:43 AM

Originally posted by CKoz View Post

Well, thanks for the chat Mad_Props and Simon. It doesn't look like my project rates an opinion from the experts so I'm gonna go ahead and stick with my formula. Take care.

Hiya

ckoz....

I think this is a bit premature since you started this thread today, no one has really had a chance to say hey

. I wish Make-a-wake was active here at OSE, we've missed him. Wake is the vintage boat guru. Here is his Super Hawaii thread @ RCgroups, you'll find it quite useful ....

ABC Super Hawaii - RC Groups

http://www.rcgroups.com/forums/showthread.php?t=1599972

Build Log ABC Super Hawaii Racing Boats - Electric

I've always wanted a super Hawaii, but I haven't scored one yet. I am glad to see a mother vintage gem around,. There's a lot of build threads the have been done on them. Is this still running the stock drive setup ? ie: twin 2:1 gear drives to a single outdrive ?.

If that was a 30" hull, 1870kv motors might be a great choice on 4s-6s power, but that's a 36" hull. 1870kv motors on 3s 25c just isn't going to cut it. Yes it'll move it, but it'll be a pig until the 3s 25c pack dies a horrible death.....

As a general rule of thumb, the bigger the hull, the lower the motor kV, but the higher the power input. For example; my 19" rigger can spin a 5700kv on 2s (7.2v), but my 30" hulls run 1800kv on 6s (22.2v) or a 26" hull on 2030kv 4s (14.4v).

In your case with that being a vintage abs hull, I would shoot for 35-40 mph. You don't need to win any races, but it'll still be a hoot to run. Assuming that your still running the stock twin motor setup, I would drop in a pair of HPI GT-550 mills (19t 1400kv 550 watts apeice) on 2x 5000mah 40c 4s in parallel for power, with a Traxxas evx 2 ESC. & a 4s lvc (low voltage cutoff). You need more torque than rpm/kV to push that hull. Twin 1400kv gt-550 mills put out some serious torque o n 4s.

The first video you'll see on Wakes' thread, he tries out the evx 2 ESC with twin titan 550 motors, which is a stock power system in the Traxxas e-maxx or villain ex boat. Well I am running a Traxxas villain IV boat (1987 version) with twin HPI gt-550 mills. My villain IV on 3s power, will chew up a villain ex on 4s & spit it out. When I put a 4s battery in it, its so overpowered from the torque it would rather f ly then float. Its much more manageable on 2s & 3s . I think it'll be a good place for you to start.

G'night

**Alexgar** · 05-09-2014, 02:24 AM

Gs he said his came with the tekin marine esc far superior to the evx2 4-32 nicad cells and 300 amp peak what a sweet score the best brushed esc ever made in my opinion

**gsbuickman** · 05-09-2014, 02:52 AM

Ooops,I missed that

. that'll power 2 gt-550 mills if he wants. I am running a pair of them on an Astroflight 212D hydro ESC, 75A & 32v. I have even run 5000mah 5s2p on it, 125A @ 18.5v. Great ESC, I also have an astroflight 207D hydro. I wished I had an Andy Kuntz ESC or 2 in my collection

...

**CKoz** · 05-09-2014, 08:08 AM

Thank you for the reply. Sorry about being anxious, I'm just excited to get this going.

I did jump the gun and purchased the 2100kv and 11.1v 2s pack. Whats the best way to recover?

Again, the plan is to go direct drive with the brushless stuff and sell the existing running hardware. I was thinking either a lower kv motor or perhaps just a smaller prop with what I just purchased????

**CKoz** · 05-09-2014, 08:10 AM

Thanks. I added to the Tekin a watercooled aluminum tube held thru the extrusion with special epoxy that is great for heat transfer...

**gsbuickman** · 05-09-2014, 12:24 PM

Mornin'

,

I may be interested in the brushed motor hydro ESC

, As far as jumping the gun goes, maybe you can cancel your order ?. If not , what's the return policy ?. If it were my super Hawaii and I was going direct drive like Make-A-Wake, I would take his advice & run the turnigy T-600 outrunner, or equivalent kV inrunner.

If you were running twin low kV motors on the 2:1 gear drive, the load would have been split between them. By the same token, its only a matter of time till the nylon gears go south. By going direct drive, now you need a motor that puts out enough torque to push the boat efficiently w/o overheating ie: Wakes' T-600 choice..

I

**CKoz** · 05-09-2014, 01:32 PM

I was able to cancel the order. Lets see how long Hobby King takes to refund my paypal account....

Anyway, thanks- I will look at T-600. Here's a question. I keep defaulting to a 3s 11.1v while everyone seems to like 4s and 6s. Whats the reasoning? Is it just more volts and less kv on the motor?

In the meantime, I machined up a special adapter plate to mount a 16v Dewalt motor to the existing gear drive. I have 2 7 cell NImh packs in series. Gotta try it....

DSCN9058.jpg

**gsbuickman** · 05-09-2014, 04:53 PM

Boy oh boy oh boy oh boy, new guys

....... Ha ha ha ha ha ha ha .....

Forget about the 3s lipo, the only thing that's going to be good for in a 36" hull, is starting a

that you can play taps to as your boat sinks. In a nutshell; the bigger the boat you run, the lower the motor kV needs to be, with an increase in voltag respectively.

The T-600 1100kv on 6s (21.6v) will spin a theoretical 23,760kv unloaded rpm. Spinning an Octura x447 prop, that should make for a respectable reliable 30-35 mph boat.

After a lot of searching, I found this on my rc crawler forum (www.rccrawler.com)

I have done some more searching and have come up with this:
A site with a list of motor specs, the dewalt 14,4 and 18V motors are on it;

ElectriCalc Motor Data

http://www.slkelectronics.com/ecalc/motors.htm

The results:
MFR Description Kv Izero Rm GEAR M T/ COMMENTS
(RPM/V) (A) (mohm) RATIO M P
DeWalt 14.4V 1230 2.9 61 1.00 F - 16-21 cells
DeWalt 18V 1130 2.6 72 1.00 F - 20-24 cells

I'm not sure if these are the 396505-21 and 396505-22 Dewalt motors they're talking about, but the Kv rating seems legit.

The cool thing is you have that brushed hydro ESC that will run the 14.4v or 18v Dewalt motors all day long. The dewalt motor you have should be 1320kv. On 4s power, it should look like this.

Dewalt 14.4v: 1320kv x 14.4v = 1900 rpm's
Dewalt 18v : 1100kv x 21.6v = 23,760 rpm's

Th 18v dewalt will work just well as the 1100kv T-600, however the t600 would last longer & be a bit more efficient. The tradeoff ?.. If you went with an 18v dewalt, you already have an ESC to run it & you could put funds towards batteries.

For 6s power you could go with 2 x 5000mah 40c 3s in series to save weight. Or you could go with a single 5000mah 40c 6s2p

http://www.hobbyking.com/hobbyking/s...5000mah+40c+6s

http://www.hobbyking.com/hobbyking/s...5000mah+40c+3s

Super Hawaii Brushless Build. Can I ask a few questions?

Super Hawaii Brushless Build. Can I ask a few questions?

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