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Old Jun 02, 2008, 09:01 AM
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State College, Valley Forge PA, LBI NJ
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Dumas 19' Chris Craft Electric to glow

Hey guys Im new to the forum but not to electric modeling I have CR-914 sailboat, Midwest Maine Lobster boat, Dumus 19' Chris Craft Racing Runabout and some HPI go fast car.


the Boat in question is my newly finished Chris craft. I Have had it running for a year on a traxxas stinger motor and some 2400mah nmhd batteries. ( They have all seen better days) My thought were to upgrade and convert to glow power.

The motors i have found are the
-O.S. Max .18CV-RMX Marine Engine with Pull-Start http://www3.towerhobbies.com/cgi-bin...?&I=LXKGR1&P=7
-AquaCraft .18 Marine Engine w/Pull Start http://www3.towerhobbies.com/cgi-bin...?&I=LXMPH1&P=7
-Traxxas TRX Pro .15 w/Pull Start Marine http://www3.towerhobbies.com/cgi-bin...?&I=LXJL60&P=7

Which one of these would be the best buy and also what other parts beside the obviouse gas tank and water cooling would I need?

Thanks
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Old Jun 02, 2008, 09:40 AM
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Euclid, Ohio, United States
Joined Sep 2004
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If you're looking for more speed, why use a nitro engine. The top speed for a rc boat model is 140 mph using a brushless motor on 48V; the nitro boats top out around 120 mph. Depending on which brushless motor/esc combo you use, you can still have reverse to get out of trouble. Any one of the brushless combos for 1/10 scale would work .
Novak has some units with a Marine mode that provides 25% reverse power.
Traxxas Velineon system was installed in a Traxxas Villiain boat for the latest issue of Radio Control Boat Modelers magazine.
AquaCraft and PorBoat also have brushless motors & escs that would fit.
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Old Jun 02, 2008, 09:55 AM
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North Central TN USA
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Most people are going the opposite way, from glo to electric. Glo engines are noisy, messy, and can be quite finiky about starting. As CGBob said there is no reverse in them either. Vibration can cause radio problems as well. Was your CC finished with hot fuel proof paint? I'd upgrade the electrics.
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Old Jun 02, 2008, 10:09 AM
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State College, Valley Forge PA, LBI NJ
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the reason i want the change is i raced my car with these batteries and they are beat and im tired of having to charge then instead of just going. The rest of the electronics are new and work GREAT.

my run times are also next to nothing and i need to charge even more batteries to make a trip worth it.

Im not really looking for speed i just want it to be able to cruise and use the boat for a long time with out waiting forever for batteries to charge.

as for paint probably not i varnished the entire boat for the best look.
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Old Jun 02, 2008, 10:38 AM
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I fly electric powered planes and recharge them at the field with a 12 amp sealed lead acid battery. For a given model, I can fly almost continuously with three lipo packs, one flying, one cooling, and one on charge. If you can use large enough capacity lipos, or A123 packs, you should be able to run smallish scale runabouts at scale 40mph speeds in much the same manner with good duration. IC powered boats are often banned where electrics are permitted or ignored. Your boat will last years longer, with almost no maintenance, using clean smooth electric power. BTW, 2.4 ghz radios work well in boats, not bothered by motor brush noise, etc.
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Old Jun 02, 2008, 10:41 AM
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so where do i find a faster charger right now its 45 min charge and 15min run time and thats a bit rediculus
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Old Jun 02, 2008, 12:08 PM
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One other aspect that may or may not apply to you is that many towns and lake owners prohibit internal combustion 2 cycle model engines due to the noise and stream of oil they leave behind. Also why many lawn mower, etc. maufacturers as well as motorcycle makers are going to 4 cycle engines.
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Old Jun 02, 2008, 12:21 PM
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Euclid, Ohio, United States
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Which charger do you have? What kind of prop is on the boat?

I sometimes hate to say this - but spend some more money and get some new batteries with a higher MAh rating and a new charger.

I have a Dynamite Prophet Plus LCD charger and routinely charge 3000 MAh packs in 35-40 (4 Amp charge rate) minutes at the lake. I also get around 30 minutes of running time in my Dumas Chris Craft Dual Cockpit runabout with those packs. I'm running an older Dumas (pre Raboesch) 3 blade 1.5" cast bronze prop, direct drive to a stock 540 size motor.
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Old Jun 02, 2008, 12:59 PM
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my set up is an older trinity 2400mah NiMH 6 cell, with Duratrax ESC http://www3.towerhobbies.com/cgi-bin...?&I=LE5361&P=1 connected to a traxxas stinger motor http://www3.towerhobbies.com/cgi-bin...&I=LXJE43&P=ML

and my charger is Dynamite vision peak. My prop is also an older 3 blade bronze prop but its about an inch in diameter ( I forget the specs)

would a higher mah like 5000 solve my problems
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Old Jun 02, 2008, 02:16 PM
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Euclid, Ohio, United States
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Batteries 101

More cells = more voltage = more speed
Larger MAh = longer run time = longer charge time

At the LHS where I work, I often compare batteries to the engine and fuel tank in a car. Battery cells are like pistons in an engine, more cells (pistons) usually means more speed; but that depends on things like the motor, prop size, and any gearing. The MAh rating is the size of the fuel tank, a higher MAh rating means a longer run time as well as a longer charge time.

I had some 6 cell 1700 MAh batteries that I run in several boats, all are direct drive from the motor to the prop - no gear or belt reduction is used. In my 1:10 scale Crackerbox, I get about a 5 minute run time. I have a 30" PT Boat with the same props as my Crackerbox, slightly different motors, and I get close to 15 minutes run time. That same 1700 MAh will run the AquaCraft Pirate Ship almost an hour.
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Old Jun 02, 2008, 08:27 PM
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You should not run lipos down past 3 volts per cell, so you usually don't need to charge them for more than 30-40 minutes. You shouldn't over-stress lipo packs by trying to pull too many amps from them continuously. A geared brush-type electric motor and proper sized and pitched prop, coupled with the proper mah capacity and 20C-rated lipo pack should give you good scale runabout speed and duration. An inexpensive Speed 500 motor ( Hobby Lobby) geared 3:1 and a 2 cell (7.4 volt) 2200mah "20C' rated lipo pack driving the right diameter and pitch prop might be a good setup. Somebody with more geared motor system experience could give better specific advice.
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