which speed control?

[escipion]

Hello!!!!
I bought the Dumas Carol Moran Harbor Tug, and I want to use a 4.8 Volt Dumas Motor, Don’t know about ESC’s. Which one do I need? Would it be better to use a Mechanical SC? If it is so, Which one do you recommend?

Thank you very much
Escipion

[CG Bob]

An ESC is better than a mechanical speed control. First the ESC is one unit, not something attached or connected to a servo; this saves weight. Second, most ESC have BEC technology, so your motor betery also powers up the radio.

I'm using one of the Airtonics BL Racer (http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXATE3&P=0) ESC's in a 1/32 scale tug that's 16" long. I'm running the unit on 6V fromAA cells - no problems with the unit.

You could also try the following units:
Duratrax IntelliSpeed (http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXGZX1&P=0)
Novak XRS (http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXGNG5&P=0)
Traxxas XL-1 (http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJM28&P=0)

[green-boat]

ProBoat also makes one, $39.

[escipion]

Hello!!!!
Thank you very much, really apreciate your help

Escipion

[Elroy68]

CG BOB, you recommended x esc's and my question is , how many turns is the Dumas 4.8 motor.? Reason why i asked is you want torque for such boats, correct. I did some checking and those esc's you typed are 15 t, 16t, 18t, 17t. The cells voltage is 4-7 cells. I don't know but with 18turn motor, heat would enter into its useage with its high rpm and a bigger 4 blade prop unless you use a gear unit which would work out. Thanks!

[Umi_Ryuzuki]

The 4.8 volt dumas is an easy motor on speed controls, I used to run two of those motors on and old Hitec ESC, and later a Duratrax Blast. The set up was direct drive, in my 56" destroyer, which weighed up to 15 lbs. The motors have no problem running on 6v or so, and two of those motors, wired in parallel will run for about an 40-60 minutes on a 6v 4ahr battery.

[escipion]

Hello!!!!
I'm learning a lot, thanks once again

Escipion

[Shaun Hendricks]

I just got mine in yesterday. Bought if off eBay, a 50A version of this (http://cgi.ebay.com/RC-Smart-Water-Resistant-100A-Speed-Controller-ESC-6USS_W0QQitemZ6046536740QQcategoryZ34058QQssPageNa meZWDVWQQrdZ1QQcmdZViewItem) one. These things are cased and conformal expoxied so they are watertight. I know the Traxxas XL-1 is not, neither are the normal Duratraxx car style ones. They seem to be a pretty good deal for the price, but then again, haven't really put this one through its paces yet. Could be junk...

Shipping took forever, slow boat FROM China... lol! :D

[tim slocum]

I second the Proboat,I really like it.If Im not mistaken the Carol Moran is a fairly small model and weight and size is probably going to be a significant factor.Shaun,the one you got off ebay looks alot like a Proboat esc.but the name is different?Copy cat?

[bill II]

Tim,
Saw this one on eBay
http://cgi.ebay.com/50A-Max-100A-Electronic-Speed-Controller-For-Boats_W0QQitemZ6042031882QQcategoryZ34058QQtcZphot oQQcmdZViewItem
Seems a reasonable enough price. :D
Cheers,
bill II

[CG Bob]

CG BOB, you recommended x esc's and my question is , how many turns is the Dumas 4.8 motor.? Reason why i asked is you want torque for such boats, correct. I did some checking and those esc's you typed are 15 t, 16t, 18t, 17t. The cells voltage is 4-7 cells. I don't know but with 18turn motor, heat would enter into its useage with its high rpm and a bigger 4 blade prop unless you use a gear unit which would work out. Thanks!
The motor turns quoted for the ESC are the minimum or fewest turns that the ESC is rated for. All are rated for stock motors of 27 turns, which is above the # of turns listed.
Airtronics BL Racer - For 18 Turns and above.
Duratrax - For stock motors having no fewer than 18 turns.
Novak - 15 turn motor limit (again the min # of turns).
Traxxas - This speed control handles 17 Turns and above.

The Dumas 4.8V motor is a standard stock motor rated at 4.8 - 7.2V. Runing at the lower voltage will reduce the amount of heat generated by the system, and yet still be fast enough for the tug. A general rule of thumb for a direct drive set up is that the prop diameter should not exceed the motor can diameter. If the prop diameter is larger than the motor can, then a red gear (reduction unit) is needed.

Two other units to consider are the EA Electronics Tiny Smart Control (http://www.eaelec.com/tiny.htm), and the MCD Ultra Minicon (http://www.modelcontrol.com/sminicon.htm).


The ProBoat ESC is not necessarily the best one for slow speed control. It tends to like the medium to high motor speeds better.

[Elroy68]

Thanks, all my stuff is 6-12 cells but have one esc CC 55 for 5-14 cells and do run a Hughey gear setup in one, thanks again!

[Shaun Hendricks]

Tim,
Saw this one on eBay
http://cgi.ebay.com/50A-Max-100A-Electronic-Speed-Controller-For-Boats_W0QQitemZ6042031882QQcategoryZ34058QQtcZphot oQQcmdZViewItem
Seems a reasonable enough price. :D
Cheers,
bill II

Yup, that's the one I have... just did some testing on it this morning on some gear that's kind of beat up, old Futaba 2ch & Futaba receiver. The ESC seems to have a 'dead' spot, or it's my gear, which it is I don't know. Small jump to motor running, smooth up to mid point then <dead> then jump to 2/3 point speeds and smooth there on up. This is on an unloaded motor. I'll have to test with my better gear and several motors to let you know how it really behaves.

[bill II]

Yup, that's the one I have... just did some testing on it this morning on some gear that's kind of beat up, old Futaba 2ch & Futaba receiver. The ESC seems to have a 'dead' spot, or it's my gear, which it is I don't know. Small jump to motor running, smooth up to mid point then <dead> then jump to 2/3 point speeds and smooth there on up. This is on an unloaded motor. I'll have to test with my better gear and several motors to let you know how it really behaves.
I'd be interested what your tests reveal.
At that price, I was thinking of giving one a try.
What's the brand name?

[Shaun Hendricks]

I'd be interested what your tests reveal.
At that price, I was thinking of giving one a try.
What's the brand name?

Himark... at least according to the single page 'instruction' sheet that came with it. It is a fixed ESC and does not have any ability to be programmed. It may have some kind of neutral detection circuit in it though... I'll figure that out during the testing.

[Shaun Hendricks]

Well, broke out one of the nice cars and my nice surface radio. Hooked up the Himark ESC in place of the cars ESC and a small Mabuchi 380 racing motor to see how the ESC would perform under a light load. Still a little jumpy off 'neutral' on the small motor which tells me it wasn't the higher powered cobalt's fault for the start. Under load this will likely not be a large problem but probably not the best speed controller for precision docking or low speed driving. With the JR XS3 radio and RS300 receiver, the motor was smooth throughout the speed range after 'start'. Tested with the Super 400 Cobalt and it too was smooth and responsive in both forward and reverse.

Tested for a neutral detect by putting a bias signal on the receiver and interestingly enough, the ESC has a lockout circuit to prevent this. If it is started under signal, it shuts down, which is probably a safety measure. No mention of this 'feature' is made in the instructions. The neutral point is very broad, so it probably isn't an issue to the ESC, however, it does not ease into speed as noted above.

There is no delay in the reverse function, it goes from full forward to full reverse as fast as your finger can move the trigger. This is heck on motors but as long as you have a higher amount of 'shock reserve' in Amps than your motor can pull, it shouldn't hurt the ESC. If I were using a motor that drew 40 AMPs, I'd probably hook it up to the 100A version of this speed controller, not the 50A like I'm testing.

For the money it appears, in a static test environment, to be a decent/functional controller for fast or sport boats. It probably would be okay in models like the Bristol Bay or other 'scale' boats but I'd think only in a geared situation, direct drive would be 'jumpy' with that sudden 'on'. On very large scale ships, it probably would also be okay because while the props would spin up suddenly, such large ships don't move all that fast so you'd be dealing with cavitation for a moment anyway, and most of them are geared pretty low for scale speed as well.

[escipion]

Hello!!!!
I want to thank you all for your comments

Escipion

[bill II]

Well, broke out one of the nice cars and my nice surface radio. Hooked up the Himark ESC in place of the cars ESC and a small Mabuchi 380 racing motor to see how the ESC would perform under a light load. Still a little jumpy off 'neutral' on the small motor which tells me it wasn't the higher powered cobalt's fault for the start. Under load this will likely not be a large problem but probably not the best speed controller for precision docking or low speed driving. With the JR XS3 radio and RS300 receiver, the motor was smooth throughout the speed range after 'start'. Tested with the Super 400 Cobalt and it too was smooth and responsive in both forward and reverse.

Tested for a neutral detect by putting a bias signal on the receiver and interestingly enough, the ESC has a lockout circuit to prevent this. If it is started under signal, it shuts down, which is probably a safety measure. No mention of this 'feature' is made in the instructions. The neutral point is very broad, so it probably isn't an issue to the ESC, however, it does not ease into speed as noted above.

There is no delay in the reverse function, it goes from full forward to full reverse as fast as your finger can move the trigger. This is heck on motors but as long as you have a higher amount of 'shock reserve' in Amps than your motor can pull, it shouldn't hurt the ESC. If I were using a motor that drew 40 AMPs, I'd probably hook it up to the 100A version of this speed controller, not the 50A like I'm testing.

For the money it appears, in a static test environment, to be a decent/functional controller for fast or sport boats. It probably would be okay in models like the Bristol Bay or other 'scale' boats but I'd think only in a geared situation, direct drive would be 'jumpy' with that sudden 'on'. On very large scale ships, it probably would also be okay because while the props would spin up suddenly, such large ships don't move all that fast so you'd be dealing with cavitation for a moment anyway, and most of them are geared pretty low for scale speed as well.
Shaun...thanks for the info.
I'd be using it in a 30" scale boat w/ a geared drive motor...may be just the ticket.
Sure like the price. :D

[JonV]

I have a ProBoat ESC.
But i have a huge problem with thermal cutoff.
It Cut power to the engine so i have to swim and get it.
It happens from 1 to 15 min driving.
Sometimes it dies after 1 min and other times it dies after 15 min.
Not reliabel :(
my friend have the same ESC and have exactly the same problem.




http://www.offshoreelectrics.com/images/forsale_esc/proboat_esc.jpeg

Pro Boat’s new waterproof marine electronic speed control is definitely one of the best new values in model boating.
Anyone can upgrade their RTR boat from a mechanical speed control to the precision of a fully proportional ESC with reverse.

The unit’s completely potted electronics are sealed in epoxy and encased in a blue anodized aluminum shell that keeps operating temps cool.
In addition to being inexpensive and waterproof, no programming is required. Set up is as simple as turning on the transmitter, turning on the receiver and moving the throttle to full forward, then full reverse.
The speed control automatically memorizes the initial movements and provides proportional control between the extremes.




Forward: yes


Reverse: yes
Battery Eliminator Circuit (BEC): yes
Continuous Maximum Current: 50 amps
Input Voltage: 4-10 cells (4.8-12 V)
Dimensions: 42 x 47 x 13 mm
Weight: 89 g









I Use 8,4V 4000Mah batteries and a 19turn engine
The ESC is spesified down to 15Turn

[CG Bob]

Jon,

You have to think of the entire system, not just the ESC. What type of motor? What is the prop diameter and pitch? What size and type of battery? Is your system direct drive or have a gear reduction? The reason the ESC is cutting off thermally could be related to any of these items.

I'll make some comparisons to auto racing. NHRA dragsters and funny cars can reach speeds of over 200 mph; they are fast but only for one trip of 1/4 mile. Some of NASCAR and IRL races are 500 miles long. Nobody would put a dragster engine in an IRL car, even though both use similar fuel. A lot of the 10-19 turn motors are designed for a short quick sprint race of less than 5 minutes with batteries of 4.8-7.2V. Trying to run that motor for 20 minutes with a 4000 mAh battery will cause excessive heat; and the thermal cutoff will shut everything down.

I have some 1500 mAh NiCd battery packs that I use in some of my boats. I have a 1:10th scale Crackerbox runabout where I get about a 5-7 minute run before the battery dumps. The Crackerbox has a stock motor and an Octura X430 prop on direct drive. I also have a 1:32nd scale model of an Elco 80' PT boat, where I get about a 15 minute run with the same battery pack. The PT Boat has counter rotating X430 props on direct drive to a pair of stock motors. The PT boat motors are connected to a single ESC. The PT seems just as fast as the Crackerbox. I just purchased one of the AquaCraft King's Ransom pirate ships and got almost an hour run on the same 1500 mAh battery.

[JonV]

It`s direct drive
The battery is a Jamara product 8,4 4000Mah
The engine is a Chameleon2 Pro 19turn engine.
Prop i use is a S-215 Prather 41mm.

The Boat is a Graupner Red Stiletto.
The most anoying part is it can happend after 1 or 15 min.
The boat runs Great when running. good speed :)

[CG Bob]

Most of the rc car & boat motors have a can diameter of about 1.5" (36 mm). Try using a smaller prop or one with a little less pitch, and the unit will run cooler; which should eliminate the ESC thermal overload. You can always water cool the motor. A general rule is that the prop diameter should not exceed the motor can diameter for a driect drive set up. If the prop diameter is bigger than the motor diameter, a gear or belt reduction unit is needed.

[conder53]

Does anyone have a contact or website so that I can purchase one of the himark marine esc. Thanks

Alan

[bill II]

Hi Alan,
It's on eBay...there's some specs & pics also.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170022283956&ssPageName=MERCOSI_VI_ROSI_PR4_PCN_BIX&refitem=6042031882&itemcount=4&refwidgetloc=closed_view_item&refwidgettype=osi_widget

Hope it's what you need.
Bill

[Ghost 2501]

jon v, in relation to post 19, I have one of those in a speed boat, and its faultless :) for high current use i swear by it

[conder53]

Thanks Bill exactly what I need

Alan

[misfitsailor]

Yes, the "Hong Kong blues" ESC's do use neutral detection, where ever you leave your throttle trim, that is where neutral is when you turn on the boat's power switch. I run two of these, and want more. Mine have had no issues, or dead spots. I have use one with 12 volts and the other with 6 volts with equally satisfying results. These are sold on Ebay with and without connectors, so look close. Horizon sells what looks like the same one for $40, if you don't like international affairs.
http://www.horizonhobby.com/Products/Default.aspx?ProdID=PRB2314