Can I use car ESC w/Futaba 9 channel rx in a boat?

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Jim Parker - 02 Jul 2005 02:54 GMT

Hi folks,
Hopefully there is someone out there who can guide me in
my quest to use an ESC (LRP F1 reverse digital) with a
Futaba (9CAP Tx/R149dp Rx).
Some background info: Boat is a scratch build stand-off
scale WW1 battleship (dreadnaught style) five feet long and
18 in. beam. I was using an old Dumas 6v motor with the
wirewound resistor fwd/rev speed control. It worked fine but
the ship was slower than my buddy's who was running the a
Dumas 12 volt setup.
In my quest for more speed I put in a RS550 can motor and
ran it instead. It ran faster but the motor got pretty hot
after about 20 minutes of running. I then put in a second
identical motor in parallel (electrically and mechanically)
to lessen the load on each motor. The boat ran faster but I
burned up the fuse(charred the whole fuse holder) on the
mechanical speed control. (May have had a bad connection
with resultant heat buildup.) I rewired the speed control
with 14 ga. wire and 30 amp fuse. Worked ok but wires seemed
to get hot and I decided to go the route of using an ESC.
After reading the instructions for the ESC (smart move) I
have some questions regarding hooking it up.

Now for the questions.
1) Since the ESC uses a batt (6v gel cell) to power the
motor and the rx, with it's connected servos, can I leave
the existing receiver battery (2nd 6v gel cell) connected to
the rx when connecting the ESC?
2) Can I use a Y harness to put a second servo on the
throttle(ESC) rx channel to control a switch for turning on
and off a pump motor? It's used to pump water thru tubing
for motor cooling.
3) Very Important! Do I use the ESC on/off switch if I have
both batteries connected? This seems to be the real problem.
How do I use it if I must? Leave off? Leave on? Switch on
and off with rx power switch? Will power from the Rx batt
affect the ESC in a bad way with any switch combination?

I don't want to hook up anything until I get some kind of
confirmation that this setup will work. The dealer will take
the ESC back if it can't be used. I can't chance ruining it
as it's expensive.

I've carefully read the instructions and that is why I'm
asking. I've got some doubts. I'm not new to RC. Been flying
airplanes for 20 years. This boat project is kinda new to
me.

If anyone has done anything like this please respond. If
there are web sources with answers please post where they
are. ( I have been looking around but found nothing so far
that addresses my questions.) Admittedly, this is a bit out
of the norm.

Thanks for any help. If I wasn't clear on anything above
please ask. I'll do my best to clarify.

Happy boating...Jim

Reply to this Message

Funfly3 - 02 Jul 2005 08:51 GMT

> Hi folks,
> Hopefully there is someone out there who can guide me in
> my quest to use an ESC (LRP F1 reverse digital) with a
> Futaba (9CAP Tx/R149dp Rx).

I hope your running the 9CAP on a legal frequency 27mhz or 40mhz in the UK
not 35Mhz ??????(if you are in the UK)
Some background info: Boat is a scratch build stand-off

> scale WW1 battleship (dreadnaught style) five feet long and
> 18 in. beam. I was using an old Dumas 6v motor with the
[quoted text clipped - 19 lines]
> the existing receiver battery (2nd 6v gel cell) connected to
> the rx when connecting the ESC?

not sure why you have two batteries but with a ESC unless both batteries are
powering the motor its a waste
2) Can I use a Y harness to put a second servo on the

> throttle(ESC) rx channel to control a switch for turning on
> and off a pump motor? It's used to pump water thru tubing
> for motor cooling.

dont add complications use a simple water pickup behind the props but your
idea will work

> 3) Very Important! Do I use the ESC on/off switch if I have
> both batteries connected? This seems to be the real problem.
> How do I use it if I must? Leave off? Leave on? Switch on
> and off with rx power switch? Will power from the Rx batt
> affect the ESC in a bad way with any switch combination?

just use the swicth on the ESC and disconnect the reciever switch

> I don't want to hook up anything until I get some kind of
> confirmation that this setup will work. The dealer will take
[quoted text clipped - 16 lines]
>
> Happy boating...Jim

Reply to this Message

Jim Parker - 02 Jul 2005 18:16 GMT

> > Hi folks,
> > Hopefully there is someone out there who can guide me in
> > my quest to use an ESC (LRP F1 reverse digital) with a
> > Futaba (9CAP Tx/R149dp Rx).

> I hope your running the 9CAP on a legal frequency 27mhz or 40mhz in the UK
> not 35Mhz ??????(if you are in the UK)

Yes, I'm legal. As a USA resident I'm running on 50mhz
(legal anywhere) with an FCC Technicicians license. I bought
the radio to use both in air and on surface.

(snip some)

> > After reading the instructions for the ESC (smart move) I
> > have some questions regarding hooking it up.
[quoted text clipped - 4 lines]
> > the existing receiver battery (2nd 6v gel cell) connected to
> > the rx when connecting the ESC?

> not sure why you have two batteries but with a ESC unless both batteries are
> powering the motor its a waste

I want to use two batteries as I'm using all 9 rx channels
with some heavy duty servos. If I just use the ESC and the
motor batt to power the rx servos, I don't think the ESC
wire to the rx will handle the current necessary to power
all the servos. That's why I want separate batteries. Hope
that clarifies it somewhat.

> 2) Can I use a Y harness to put a second servo on the
> > throttle(ESC) rx channel to control a switch for turning on
> > and off a pump motor? It's used to pump water thru tubing
> > for motor cooling.

> dont add complications use a simple water pickup behind the props but your
> idea will work

Boat doesn't go fast enough for water pickup type of
cooling. It also won't work in reverse. Besides, I have the
circuit already in place, just need to know if I can tie in
another servo without any problems. I have the water going
out the side of the ship ala bilge pumps...looks good! I'd
like to keep that function.

> > 3) Very Important! Do I use the ESC on/off switch if I have
> > both batteries connected? This seems to be the real problem.
> > How do I use it if I must? Leave off? Leave on? Switch on
> > and off with rx power switch? Will power from the Rx batt
> > affect the ESC in a bad way with any switch combination?

> just use the swicth on the ESC and disconnect the reciever switch

As I said above, I can't due to wire size limitations of the
servo wire. I'd probably burn out the wire when using some
of the larger servos. The ESC is normally used in a car and
is only expected to have one other servo (steering) hooked
into the rx. I have three 1/4 scale servos rated at over 300
in. oz. plus the other 6 or so standard servos.

(snip some more)

If I have to I'll just go back to a single motor and the
wirewound speed control. I was hoping to be able to use the
ESC, but unless someone can convince me what I want to do
will work, I won't plug it in. If I burn it up I can't get
my money back.

Thanks for responding. Hopefully someone has done something
like this and can guide me.

> > Thanks for any help. If I wasn't clear on anything above
> > please ask. I'll do my best to clarify.
> >
> > Happy boating...Jim

Reply to this Message

Umi_Ryuzuki - 02 Jul 2005 17:25 GMT

In Scale modeling, most of the boats need ballast to get them down t
the waterline.
Using extra batteries is preferable rather than sticking in chunks o
lead or a bag of BBs. A five foot ship will likely run up 15-30 lbs t
the waterline.

The reciever battery is fine. *Just leave the BEC in the "off
postion.*
Often in scale ships, there are more than two servos. when you get u
to four or six servos, the BEC can't provide the proper amperage, an
the system gets jittery.

The reason the wiring is getting hot, is that the motor is drawing to
many amps.
If you are running the twin motors in parallel, you just doubled th
amp draw. This is killing the fuses and wiring. Some nice 12-14 vol
pittman motors would be more than enough to run a five foot scale shi
and draw 1/4 of the amps racing motors do. You could also gear dow
the motors.
If the motors are running in series, Positive to one motor, Negative t
second motor and a wire between the two, then you might be fine. It wil
still try to draw up to 3 or more amps.

2. Use a an additional channel to run the cooling pump, or just mount
switch somewhere in the boat to run it continiously. Tie it dirctly to
battery. Scale boats look good with 2-4 bilge water outlets pouring
constant stream out the side.

3. Yes leave the switch in the off postion, or cut the switch off, an
attach a deans plug to the wires so you can reattach the switch fo
other uses. If you do use it, do not add the extra reciever battery.
If you have more than 4 servos, you may be overdriving the BEC, as the
are typically designed to support only a steering servo in a car. O
rudder, elevator, and aelerons in a plane, but not much more.

A side note, Some of the old ESC do not speak with the new Futaba PC
digital signals. Futaba created some new language, and older ESC don'
understand

--
Umi_Ryuzuk

Reply to this Message

Jim Parker - 09 Jul 2005 02:24 GMT

> In Scale modeling, most of the boats need ballast to get
> them down to
[quoted text clipped - 4 lines]
> 15-30 lbs to
> the waterline.

Umi, Thanks for responding. I haven't weighed it but it
probably is about 30 pounds.
To update you...I went back to the original motor which is
an old (probably 20+ yrs.) Pittman 6 volt unit which I had
been using. I think I'll stick with that for a while. I came
to the conclusion that I would have to spend money on an ESC
and then would have to buy an extra motor battery to be able
to run long enough. Pulling 19 amps on a 10Ah batt. would
kill it in a short time. Additionally, I don't know how long
the motors would last at that rating. I'm probably running
them past their designed current load.

> The reciever battery is fine. *Just leave the BEC in the
> "off"
[quoted text clipped - 4 lines]
> amperage, and
> the system gets jittery.

Yes, that is the reason I wanted to use two batteries in the
first place. I'm running 9 servos (three are high current
units at 330+ in. oz.) which would put too much load on the
servo wire from the ESC to the rx.

> The reason the wiring is getting hot, is that the motor is
> drawing too
[quoted text clipped - 13 lines]
> fine. It will
> still try to draw up to 3 or more amps.

If I wanted to keep this motor I would have to reduce the
size of the prop or put in a bigger gear reduction to reduce
the current draw.

> 2. Use a an additional channel to run the cooling pump, or
> just mount a
[quoted text clipped - 3 lines]
> outlets pouring a
> constant stream out the side.

Now that I'm back to the original motor, I'm just going to
use the pump to simulate bilge pumps. It does look neat!

> 3. Yes leave the switch in the off postion, or cut the
> switch off, and
[quoted text clipped - 8 lines]
> rudder, elevator, and aelerons in a plane, but not much
> more.

Understood and agree.

> A side note, Some of the old ESC do not speak with the new
> Futaba PCM
> digital signals. Futaba created some new language, and
> older ESC don't
> understand.

I did not know this. Thanks for the heads up. I do have some
old Novak speed controls I used in cars years ago. They are
forward only ESC's and I can't use them in the ship.
--

> Umi_Ryuzuki

Umi, Thanks for your thoughtful input. It helped a lot in
making up my mind.

Jim Parker

> ------------------------------------------------------------------------
> Umi_Ryuzuki's Profile:
> http://www.rcgroups.com/forums/member.php?action=getinfo&userid=13978
> View this thread:
> http://www.rcgroups.com/forums/showthread.php?threadid=388811

Reply to this Message

John Mianowski - 03 Jul 2005 02:50 GMT

>Hi folks,
> Hopefully there is someone out there who can guide me in
>my quest to use an ESC (LRP F1 reverse digital) with a
>Futaba (9CAP Tx/R149dp Rx).

I've built a lot of R/C warships. I've never used that particular
ESC.

> Some background info: Boat is a scratch build stand-off
>scale WW1 battleship (dreadnaught style) five feet long and
[quoted text clipped - 5 lines]
>ran it instead. It ran faster but the motor got pretty hot
>after about 20 minutes of running.

I honestly don't know what motor you're using. Is it some kind of
racing motor? If so, it's big-time overkill. I use surplus 550 tool
motors @ 6V all the time & never have any heating problems running all
day.

>I then put in a second
>identical motor in parallel (electrically and mechanically)
[quoted text clipped - 4 lines]
>with 14 ga. wire and 30 amp fuse. Worked ok but wires seemed
>to get hot and I decided to go the route of using an ESC.

I can't imagine what you're doing to draw over 30A. Nothing I use
draws even 10A, stalled.

>After reading the instructions for the ESC (smart move) I
>have some questions regarding hooking it up.
[quoted text clipped - 4 lines]
>the existing receiver battery (2nd 6v gel cell) connected to
>the rx when connecting the ESC?

Only if the batteries are identical. I use 2 @ 6V gel cells in most
of my larger ships. If you wire them in parallel, it extends your run
time. I usually run my pump off of one, & everything else off of the
other, keeping them separate. Another idea is to isolate "dirty"
(motors, relays, anything that tends to put spikes on the power) from
"clean" (everything else; radio & servos) power.

>2) Can I use a Y harness to put a second servo on the
>throttle(ESC) rx channel to control a switch for turning on
>and off a pump motor? It's used to pump water thru tubing
>for motor cooling.

I've never needed to water cool an electric motor, nor have I ever
seen a R/C warship that needed it (& I've seen a lot of them). I'd
just leave the pump running full time, if you want to pump water (for
cooling, emptying the hull, or other).

>3) Very Important! Do I use the ESC on/off switch if I have
>both batteries connected? This seems to be the real problem.
>How do I use it if I must? Leave off? Leave on? Switch on
>and off with rx power switch? Will power from the Rx batt
>affect the ESC in a bad way with any switch combination?

I'm not familiar with that ESC, & I've never seen/used one that has an
on/off switch. I always run everything off of the main 6V batteries.
Radios, ESCs, etc. other R/C stuff run off of 6V just fine & there's
no point in using a standard receiver battery (4.8V).

> I don't want to hook up anything until I get some kind of
>confirmation that this setup will work. The dealer will take
>the ESC back if it can't be used. I can't chance ruining it
>as it's expensive.

A great ESC for warships is the MTronics Sonik4 Marine 15:

http://www.hobbypeople.net/gallery/159101.asp

> I've carefully read the instructions and that is why I'm
>asking. I've got some doubts. I'm not new to RC. Been flying
[quoted text clipped - 6 lines]
>that addresses my questions.) Admittedly, this is a bit out
>of the norm.

Not out of the norm for some people:

http://www.ntxbg.org

JM

>Thanks for any help. If I wasn't clear on anything above
>please ask. I'll do my best to clarify.
>
>Happy boating...Jim

Reply to this Message

Jim Parker - 06 Jul 2005 03:07 GMT

> >Hi folks,
> > Hopefully there is someone out there who can guide me in
[quoted text clipped - 3 lines]
> I've built a lot of R/C warships. I've never used that particular
> ESC.

John,
Sorry for the delay in responding...had family over for
the holidays and didn't have time for hobby stuff.
The ESC I mentioned above is for RC car use. It was
recommended by the hobby shop I frequent. It was his best
guess as he didn't really know what kind of setup I had.
I've since returned it as I can't find a definitive answer
to my questions.

> > Some background info: Boat is a scratch build stand-off
> >scale WW1 battleship (dreadnaught style) five feet long and
[quoted text clipped - 10 lines]
> motors @ 6V all the time & never have any heating problems running all
> day.

The motors are labeled with RS550 on the can. They are
simple can motors with a steel sleeve wrapped around them to
enhance the magnetic properties. I got them many years ago
at the WRAM show for about $5 each and planned to use them
in an electric airplane. Never built the plane so the motors
were hanging around and available. I tested them and found
they would run about 10,000 rpm at 6 v. As I was trying to
get more speed out of the boat I thought I would try one out
and see what happened.

> >I then put in a second
> >identical motor in parallel (electrically and mechanically)
[quoted text clipped - 7 lines]
> I can't imagine what you're doing to draw over 30A. Nothing I use
> draws even 10A, stalled.

What I have: 2 RS550 motors driving a Dumas 3:1 reduction
setup into a single shaft with a 3" dia., four blade Rivabo
brass prop.

Today I tried the boat under load in the water with a 30
A ammeter in the circuit. With both motors running in
parallel at 6 volts the meter indicated 23 amps.
Disconnecting one motor, electrically and mechanically,
reduced the current to 19 amps. There isn't much speed
difference in the water whether I run one or two motors. I
suspect the load (heat buildup) in the motors is less
running both motors. I have a pump and aluminum tubing
around both motors for cooling. I seems to help a lot.
Unfortunately while running the boat this morning the
wirewound speed control burned up. Apparently it isn't
designed for that much current on a continuous basis.
UGH! Now I *have* to buy an ESC.

> >After reading the instructions for the ESC (smart move) I
> >have some questions regarding hooking it up.
[quoted text clipped - 11 lines]
> (motors, relays, anything that tends to put spikes on the power) from
> "clean" (everything else; radio & servos) power.

I have 2 6v gel cells. One for the radio as I'm running
about 9 servos with three of them being 330 oz. quarter
scale units. The other is for driving the motor. I have a
third 12 volt gel cell batt. for the pump and any other
elec. circuits.

> >2) Can I use a Y harness to put a second servo on the
> >throttle(ESC) rx channel to control a switch for turning on
[quoted text clipped - 16 lines]
> Radios, ESCs, etc. other R/C stuff run off of 6V just fine & there's
> no point in using a standard receiver battery (4.8V).

The car ESC's have the on/off switch as they are used to
power the receiver and steering servo. I think the racing
boats also use this type of ESC.
Batteries are not a problem I still need to add about 10
pounds of lead shot for ballast.

> > I don't want to hook up anything until I get some kind of
> >confirmation that this setup will work. The dealer will take
[quoted text clipped - 4 lines]
>
> http://www.hobbypeople.net/gallery/159101.asp

Thanks! That would be perfect if not for the current draw in
my boat. I'm slightly over the rating for that ESC even
using only one motor.

> > I've carefully read the instructions and that is why I'm
> >asking. I've got some doubts. I'm not new to RC. Been flying
[quoted text clipped - 12 lines]
>
> JM

WOW! Now that's combat! What I'm doing is a lot simpler. I
get together once a year with a group of guys and go the
Adirondacks to a hunting camp for a week. Two of the other
guys built these 5 ft. dreadnaught style battleships and
mounted paintball guns on them and went out trying to blast
the other guy with paint. The guy with the most hits on his
ship loses. All in great fun. I was at a real disadvantage
with a slower ship and thats the reason I'm trying to get
more speed.

Oh, yeah. The hat your sporting looks cool! (grin)

Thanks for the response and the help. Your site has some
neat stuff on it. I'll be going back to visit it soon.

Happy battling.....Jim P.

Reply to this Message

John Mianowski - 06 Jul 2005 04:14 GMT

>> On Fri, 1 Jul 2005 21:54:56 -0400, "Jim Parker"
><jparker@nep.net>
[quoted text clipped - 51 lines]
>get more speed out of the boat I thought I would try one out
>and see what happened.

See: http://www.mabuchi-motor.co.jp/english/product/index.html

Should draw 1.15A with no load (12V). I have no idea what you're
doing to make them draw so much. Maybe modified to go extra fast,
for aircraft use?

Then again, if you're trying to crank more speed out, that may be the
issue. In our club, ships are restricted to a max. speed based on
what the original could do. We're not trying to race, we're trying
to keep them looking like ships with scale speeds relative to one
another.

>> >I then put in a second
>> >identical motor in parallel (electrically and
[quoted text clipped - 15 lines]
>setup into a single shaft with a 3" dia., four blade Rivabo
>brass prop.

That's 3:1 reduction, as in 3 turns of the motor = 1 turn of the prop,
not the other way around? I don't know anything about that prop
except that I see Rivabo mentioned along with scale models so it
shouldn't be anything too radical. 3" seems enormous, though, for a
ship that size. I'd check the scale size of the props & run something
close to what the original ship had, both in terms of size & number.

> Today I tried the boat under load in the water with a 30
>A ammeter in the circuit. With both motors running in
[quoted text clipped - 9 lines]
>designed for that much current on a continuous basis.
>UGH! Now I *have* to buy an ESC.

I run several ships with pairs of what should be very similar motors,
on 6V, & never have one run hot, even with props clogged up with crap.

>> >After reading the instructions for the ESC (smart move) I
>> >have some questions regarding hooking it up.
[quoted text clipped - 75 lines]
>my boat. I'm slightly over the rating for that ESC even
>using only one motor.

I use this ESC in 3 different ships, that all run 6V gel cells &
Mabuchi RS550PF tool motors. They run all day & never get hot. 2 of
the 3 have chain reduction drives & the 3rd is direct drive.

>> > I've carefully read the instructions and that is why
>I'm
[quoted text clipped - 27 lines]
>with a slower ship and thats the reason I'm trying to get
>more speed.

Trouble is, you can get into an escalating speed race as well as an
arms race unless you establish some parameters. It sounds as though
your models aren't based on any real ships, which might make it hard
to keep things reasonable & realistic.

JM

>Oh, yeah. The hat your sporting looks cool! (grin)
>
>Thanks for the response and the help. Your site has some
>neat stuff on it. I'll be going back to visit it soon.
>
>Happy battling.....Jim P.

Reply to this Message

Jim Parker - 07 Jul 2005 04:28 GMT

Snip a bunch> >

> >The motors are labeled with RS550 on the can. They are
> >simple can motors with a steel sleeve wrapped around them to
[quoted text clipped - 17 lines]
> to keep them looking like ships with scale speeds relative to one
> another.

Hi John,
I checked out the site and It appears the RS550 is the
motor I have. I don't believe the motors are modified but
then they might be. I got them so long ago for use in an
airplane that they may be some special wind for that
purpose. I just don't know.
I am coming to the conclusion that I simply have too much
prop for this motor and thats the reason for the high
current.

Snip some

> >What I have: 2 RS550 motors driving a Dumas 3:1 reduction
> >setup into a single shaft with a 3" dia., four blade Rivabo
[quoted text clipped - 6 lines]
> ship that size. I'd check the scale size of the props & run something
> close to what the original ship had, both in terms of size & number.

Yes, it is 3 turns of the motor to one turn of the prop. The
prop worked fine with the old Dumas 6 volt motor and 3:1
reduction. I never measured the current while operating but
today I put the old motor on test meter and measured stall
current and it was only about 7-8 amps. Not enough to burn
up anything.

Snip some more...

> >> I've never needed to water cool an electric motor, nor
> >have I ever
[quoted text clipped - 3 lines]
> >water (for
> >> cooling, emptying the hull, or other).

Water was not needed with theold motor. It helped with the
new motors. I see your point of just turning the pump on
before sailing and off when done. It's much simpler to do.
I'll probably do that from now on.

snip some more....

> >> A great ESC for warships is the MTronics Sonik4 Marine 15:
> >>
[quoted text clipped - 7 lines]
> Mabuchi RS550PF tool motors. They run all day & never get hot. 2 of
> the 3 have chain reduction drives & the 3rd is direct drive.

I may order this ESC as it seems to be a good price for what
you get.

Snip some more....

> >> http://www.ntxbg.org
> >>
[quoted text clipped - 14 lines]
> your models aren't based on any real ships, which might make it hard
> to keep things reasonable & realistic.

The models are not based on real ships. We're trying to make
them look something like the older WWI type of dreadnought.
Not scale at all. They are platforms for paintball guns and
other sundry devices to do battle. We are not out to sink or
badly damage the other ships. Counting paintball splotches
works fine for us. We also put smoke cartridges on them to
simulate smoke screens. That looks cool.
I wanted to get a motor that would match the speed of the
other boats and do it cheaply by using what I had on hand. I
think I may just go back to the slower setup and keep it
simple...and more reliable.

Thanks for all your help and insight. It's much appreciated.

Jim P.

Reply to this Message

John Mianowski - 08 Jul 2005 16:17 GMT

>Snip a bunch> >

>Hi John,
> I checked out the site and It appears the RS550 is the
>motor I have. I don't believe the motors are modified but
>then they might be. I got them so long ago for use in an
>airplane that they may be some special wind for that
>purpose. I just don't know.

Actually, I'd be surprised if there was any modification (like what
people do for racing cars, boats, etc.).

RS550 come in several flavors, as defined by the suffix letters.

> I am coming to the conclusion that I simply have too much
>prop for this motor and thats the reason for the high
>current.

That may be.

>Snip some
>
>> >What I have: 2 RS550 motors driving a Dumas 3:1 reduction
>> >setup into a single shaft with a 3" dia., four blade

<snip>

>Yes, it is 3 turns of the motor to one turn of the prop. The
>prop worked fine with the old Dumas 6 volt motor and 3:1
>reduction. I never measured the current while operating but
>today I put the old motor on test meter and measured stall
>current and it was only about 7-8 amps. Not enough to burn
>up anything.

Right - that's consistent with my experience. Get a ship tangled up
in weeds, etc. to the point that the motors stall & it might draw 10A,
worst case.

> Snip some more...
>
[quoted text clipped - 11 lines]
>before sailing and off when done. It's much simpler to do.
>I'll probably do that from now on.

Still, I question the need to cool at all. I'm taking 6 ships out to
a battle this weekend & none of them have ever run hot or needed any
sort of coolinig other than ambient air. Same thing for all of the
people I'll be fighting with. If you're running consistently hot,
then you've got something fouled up. At the very least, if you
determine that you really need to go as fast as you do, consider
switching over to a bigger motor. Engineer the system so that it can
handle the usage that you need it to.

>snip some more....

<snip>

> It sounds as though
>> your models aren't based on any real ships, which might
[quoted text clipped - 12 lines]
>think I may just go back to the slower setup and keep it
>simple...and more reliable.

I'm not trying to tell you what to do - if you're having fun, that's
great, keep on doing it the way you want. I'm just trying to point
out that, without some sort of structure in place, at some point
you're likely to find yourselves in a situation where somebody brings
something out that completely blows the doors off of everybody else.
That, or something completely goofy & ridiculous, like a high-speed
hydrofoil battleship, etc. This quantum leap beyond the competition
could come in the form of speed, maneuverability, firepower,
survivability, targetting/fire control, etc. When the others realize
that they can't keep up, they might quit playing which ruins the fun
for everybody.

Basing ships on actual models puts the relative strengths & weaknesses
of each ship type or class into play.

>Thanks for all your help and insight. It's much appreciated.

Happy to help.

JM

>Jim P.

Reply to this Message

Boat Hull Maker - 04 Jul 2005 01:15 GMT

> Hi folks,
> Hopefully there is someone out there who can guide me in
[quoted text clipped - 54 lines]
>
> Happy boating...Jim

V=IR or alternatively I=V/R. If load resistance (the motor) drop,
current grow exponentially, very likely burn the fuse and/or ESC.

Wire woned resistor speed control is low cost and low efficiency speed
control. The theory is to use the resistor to consume some power so the
power delivered to the motor will be reduced. If 2 motros in parrall,
that means motor resistnace reduced, the speed control consume power,
efficiency drop exponentially.

2 motors in parallel, the resistor consume even more power. Driving
power drop exponentially.

Boat model prefer low rpm and high torque motor (most lilely high number
of coil turn). So can run a larger propeller at a lower rpm, this is
the key to run a faster boat.

Use series motor connection and series battery connection, you will get
higher efficiency and more running time.

Reply to this Message

Jim Parker - 06 Jul 2005 03:19 GMT

> > Hi folks,
> > Hopefully there is someone out there who can guide me in
> > my quest to use an ESC (LRP F1 reverse digital) with a
> > Futaba (9CAP Tx/R149dp Rx).

(snip a bunch of my own stuff)

> > Thanks for any help. If I wasn't clear on anything above
> > please ask. I'll do my best to clarify.
[quoted text clipped - 3 lines]
> V=IR or alternatively I=V/R. If load resistance (the motor) drop,
> current grow exponentially, very likely burn the fuse and/or ESC.

Hi Boat hull maker,
Yes your right. By testing out the setup with an ammeter
in the circuit I found that with both motors connected I was
using 22 amps. Using one motor I was drawing 19 amps.

> Wire woned resistor speed control is low cost and low efficiency speed
> control. The theory is to use the resistor to consume some power so the
[quoted text clipped - 8 lines]
> of coil turn). So can run a larger propeller at a lower rpm, this is
> the key to run a faster boat.

I'm running RS550 can motors which turn about 10,000rpm at 6
volts. I believe they are 20 turn motors. This is an
educated guess, I don't know for sure. They are driving a
Dumas 3:1 gear reduction to a single shaft with a 3", 4
blade brass Rivabo prop.

> Use series motor connection and series battery connection, you will get
> higher efficiency and more running time.

Thanks for the suggestion to try a series connection. It
will only take a few minutes and I'll see what kind of rpm
and current draw I'll get. I can only do it on the motors as
I have only one 6 volt gel cell motor battery.

Thanks for your insight,

Jim P.

Reply to this Message

Model Forum / Radio Controlled / Water Models / July 2005

Can I use car ESC w/Futaba 9 channel rx in a boat?