Dumas Akula questions

[Kim Sleep]

I was lucky enough to bid $70.00 on a Akula sub kit just before Christmas. I was able to purchase it as I would be in Florida over the holidays, and could pick it up in person, thereby avoiding the $100.00 shipping. The kit was started with only a few glue joints to the motor and servo mounts with some sort of glue that obviously didn't stick at all, which may be why the initial builder gave up. He slopped on globs of glue in the attempt to make them stick to no avail.
So I spent 4 hours picking, scratching and sanding glue off of the parts, and I now have started fresh.
I have decided to actually "GO BY THE PLANS" for this, as what seems to screw me up in the past is attempting to upgrade as I go, leaving me with a pile of steaming Caswell droppings..
That being said, I may just save the water-tight battery container for later when I want to build a ballast, since I don't mind my batteries getting wet.

Ok, here are the questions:
-What propeller should I use to easily replace the soft, rubbery one included?. I'm certain that the soft one gave Dumas's lawyers much solace, as nobody will lose their fingers with it.

-The Dumas2004 motor. Ok, I realise that the original Dumas one is super-special, and has been kissed individually by Mr. Dumas prior to shipping, but HOLEY CRAP...they average around $70 bucks American (I'm Canadian)with out the $20 bucks shipping.
I'm not going to give you the teary eyed, I'm disabled...X number of kids crap, it just seems that there has to be some sort of 6VDc-5000RPm motor for a few bucks on EBay that compares.
Any ideas??
Thanks in advance
Kim

[Buellman1]

If you desire a Dumas motor, but don't want to pay for the name. Search for Pittman motors. That's what dumas puts their name on.. you should find them for about 10 to 15 dollars. They will state some high voltage ratings, but are still likely the 6 or 12 volt same Dumas motor.

[He Who Shall Not Be Named]

I was lucky enough to bid $70.00 on a Akula sub kit just before Christmas. I was able to purchase it as I would be in Florida over the holidays, and could pick it up in person, thereby avoiding the $100.00 shipping. The kit was started with only a few glue joints to the motor and servo mounts with some sort of glue that obviously didn't stick at all, which may be why the initial builder gave up. He slopped on globs of glue in the attempt to make them stick to no avail.
So I spent 4 hours picking, scratching and sanding glue off of the parts, and I now have started fresh.
I have decided to actually "GO BY THE PLANS" for this, as what seems to screw me up in the past is attempting to upgrade as I go, leaving me with a pile of steaming Caswell droppings..
That being said, I may just save the water-tight battery container for later when I want to build a ballast, since I don't mind my batteries getting wet.

Ok, here are the questions:
-What propeller should I use to easily replace the soft, rubbery one included?. I'm certain that the soft one gave Dumas's lawyers much solace, as nobody will lose their fingers with it.

-The Dumas2004 motor. Ok, I realise that the original Dumas one is super-special, and has been kissed individually by Mr. Dumas prior to shipping, but HOLEY CRAP...they average around $70 bucks American (I'm Canadian)with out the $20 bucks shipping.
I'm not going to give you the teary eyed, I'm disabled...X number of kids crap, it just seems that there has to be some sort of 6VDc-5000RPm motor for a few bucks on EBay that compares.
Any ideas??
Thanks in advance
Kim

Try this on for size:

http://www.sub-driver.com/electronics/speed-controllers-and-motors.html

Go for the 550. Whatever flavor you like. These are five-pole motors, with only 25 turns per pole. Hot! And el Cheapo! And they come already spark-supressed.

M

[Kim Sleep]

550?

So you mean any 550 sized motor...brushed or brushless?
such as on EBay:

eBay item number:311166933758

http://www.sub-driver.com/electronics/speed-controllers-and-motors.html

Go for the 550. Whatever flavor you like. These are five-pole motors, with only 25 turns per pole. Hot! And el Cheapo! And they come already spark-supressed.

M[/QUOTE]

[He Who Shall Not Be Named]

So you mean any 550 sized motor...brushed or brushless?
such as on EBay:

eBay item number:311166933758

http://www.sub-driver.com/electronics/speed-controllers-and-motors.html

[ATTACH=CONFIG]29551[/ATTACH] [ATTACH=CONFIG]29553[/ATTACH] Go for the 550. Whatever flavor you like. These are five-pole motors, with only 25 turns per pole. Hot! And el Cheapo! And they come already spark-supressed.

M

[/QUOTE]

Nope. The 550 designator only tells you the armature diameter, number of poles and case length. Tells you nothing about how many turns. You have no idea from the '550' what the rated voltage is or the number of turns per pole.

The 550 we offer is rated for 12-volts and is pretty hot at 25-turns per pole. Can't speak for the 'other' 550's out there in motor land.

Guess how I worked out the turn-count on our motors? ...

David

[Scott T]

You probably crushed your toy rocks to dust when you were a baby. lol

Scott

[He Who Shall Not Be Named]

You probably crushed your toy rocks to dust when you were a baby. lol

Scott

You think you're joking.

I once got so frustrated with a rocket diorama (I was filming a 'take-off' scene for an 8mm movie) -- I could not get the smoke pot lit -- that I stomped the entire model launch gantry, rocket, support vehicles, and pyro's into the mud. Chris was about nine at the time. To this day (he's now almost fifty) he gets the shakes whenever we talk about it. He says he never saw me so mad as on that day. I do remember pulling about 1/4" of K&S rod out of my foot when we got back home. Chris ran up to his room and curled into the fetal position. He has not touched so much as a model kit since.

M

[Kim Sleep]

As far as I can tell, your 550 motors are rated at 12vdc, so I will have to upgrade my system to 12vdc??

[He Who Shall Not Be Named]

As far as I can tell, your 550 motors are rated at 12vdc, so I will have to upgrade my system to 12vdc??

Yup. Fraid so.

M

[Buellman1]

Don't mess with a brushless motor in that sub. Even the 550 or 540 can motors will be overpowered and a gear reduction might be necessary.

[Scott T]

Question:
Does a speed controller reduce the voltage to give you a lower rpm/speed?
If that is true running a 12vdc motor at 6vdc would reduce the speed. Might raise amperage?

Since the motor is hot/fast speed wise for this application why not run the 12vdc motor on 6vdc? (amps?)

Scott T

[He Who Shall Not Be Named]

Question:
Does a speed controller reduce the voltage to give you a lower rpm/speed?
If that is true running a 12vdc motor at 6vdc would reduce the speed. Might raise amperage?

Since the motor is hot/fast speed wise for this application why not run the 12vdc motor on 6vdc? (amps?)

Scott T

Typically the ESC sends full battery voltage to the motor, but clipped as a chopped square wave. The on/off rate is adjusted to control motor speed. Ever notice that 'sqeal' coming from an operating ESC?

You can operate the 12-volt motor with 6-volts. Not as effecient though.

M

[Subculture]

The frequency is constant, it's the pulse width that is varied. Older esc's used the clock rate from the receiver, which gave an inaudible 50 hertz chopping rate. Once microcontroller based esc's came onto the scene, the frequency rate became independent and the rate could be set by the designer.