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The Traxxas Villain IV is an interesting model boat.
One of the features that make it almost unique is dual propellers.
As you can see from the photos there is a motor dedicated
to each prop. You may also notice that there is a right hand
and a left hand prop. This is called counter rotating. The
reason this is a benefit is because the counter rotation evens
out "torque steer", a condition where the rotating
propeller interferes with the forward motion of the boat.
It is created by rotational friction. In single propeller
boats, there is a strong tendency to steer poorly one way
and over aggressively the other. Counter rotating propellers
eliminate that trait.
Another distinguishing feature of this boat is it's
steerable outdrives. More common in RC boat models is a static
prop with a steerable rudder design. Some advantages to steerable
outdrives (where the propeller and the rudder are integrated
and turn as one unit) are: adjustable trim, support for surface
piercing props, and scale appearance. The surface piercing
props actually are "in the water" about half of
the time at planing speeds. You might think this would be
a disadvantage, but due to some insanely complicated hydrodynamic
principles, it is actually a more efficient design. Propellers
do not create thrust throughout the entire 360° rotation.
The arch of the rotation that does not create thrust only
creates drag. Essentially, by placing the prop close to the
surface the drag creating area of the arch is placed in the
air where there is almost no resistance, thereby increasing
efficiency. Whew ...
This boat is about 31 inches long, comes with two motors,
plastic props, no bearings, a mechanical speed controller,
and no electronics. There is an RTR version for those folks
who need the rest of the RC gear it takes to make the boat
function, such as a radio transmitter, steering servo, receiver,
and battery holder. The scale of the boat is fairly accurate
and it looks great in the water.
I saw huge need for improvement after running the kit
box stock for a while. I picked up an RC boating magazine
(this was years ago) and saw a bunch of nifty mods they did.
I tried them, realized a big improvement, and wanted more.
So I bought another kit (I am now on my third one !) and set
out to make the ultimate Villain IV. In the following paragraphs
I describe what those mods are. My Villain IV now does 35
MPH with standard 6 cell packs, and does so for 6-7 minutes.
This a dramatic improvement over the stock configuration.
It also handles better and is much more reliable. With 8 cell
packs it is stupid fast, almost undriveable. I once raced
a 3.5 cc tunnel boat and made it to the first turn in the
lead, made it to turn 2 just behind, and got wasted after
that. Deep vee designs just don't turn well, while tunnel
hull boats turn amazingly well. But, in a straight line I
whooped him. Nobody could believe it and I drew quite a crowd
around my nearly silent (by comparison) plastic boat. I was
a little out of place there, but I had something to prove
for all my hard work !
The Villain is at home in the rough water, something the tunnel
hull folks run scared from. It is even more fun in the waves.
I often go out on the rough water to double and triple the
waves made by big boats. It is a total gas. Hopefully soon
I will be able to put up some video of me "motocrossing"
my boat around the river.
The modifications
The text follows the thumbnails at the top
of the page, which you can click to enlarge
Picture 1
There is not much to show here except my paint job. I hated
the crummy stickers that came in the kit so I decided to paint
it. My color scheme is probably sappy, but I have no art skills
at all (as you might have noticed from my web page). I used
standard hobby paint, not the kind meant for Lexan like all
the RC cars need. I might make one recommendation: use metallic
colors, they look cool.
Picture 2
The main mod here is the addition of a plastic fin. I noticed
that the stock kit had a bad habit of "skipping out"
in a hard turn. This is mainly attributable to the characteristics
of a deep vee, not to the designer of the hull, but I wanted
to improve it anyway. I epoxied a piece of plastic from
the hull of my old boat to the bottom, paying super close
attention to angles. I filed it down a little sharper on the
leading and bottom edges to decrease drag. The performance
benefits are: better straight line tracking in rough water
and more aggressive, predictable turning. I was not sure of
the best placement for this fin, and did not experiment, however
the boat almost never "skips out" anymore.
Picture 3 & 4
Here you will see the bulk of the mods. The single biggest
problem with the boat is the motor mounts. Even the relatively
weak motors included in the kit (Mabuchi looking units) have
enough power to warp and flex them. Because of all the flexing
going on, the spur gears would often strip. My first fix was
to install two Associated on road motor spacers on the inside
of the motor mount to distribute the load. This eventually
failed as the entire vertical portion of the mount would try
to separate from the base via a long crack down the side.
My second shot at a remedy was to place both motors on a common
plate of fiberglass and attach this to the mounts. Aluminum
would be a much better material because it would aid in heat
dissipation, but I messed up the one piece I had. Underneath
the motor mounts (in between the hull pieces) is another fiberglass
plate, also connecting the mounts together. This absolutely
solved any flexing and gear stripping problems. This mod mainly
improves reliability and may improve handling due to a more
rigid hull.
The stock motors were replaced by two Reedy (15 turn
double) Sonic motors. These motors have the large commutator
and generate a more usable power band (more emphasis on low
RPM power), and are easy on brushes. I highly recommend the
large commutator Sonic series of motors for any application.
The recommended brushes are the Reedy 737's. These brushes
do not have a super high silver content and last like the
Energizer bunny, and so will the commutator. This mod increases
speed tremendously if applied in conjunction with better props
(see below).
Motor cooling is essential in a boat due the continuous
high current load the motors are under. Boats are hell on
electric motors. If water itself doesn't harm them, the high
stresses and heat they are subjected to eventually will. I
had a tough time finding pre-made motor coolers (the silver
looking tubes wrapped around the motors), so I made some.
I used soft aluminum tubing from a hobby store, wrapped it
around a motor, removed the coil , made it a little smaller,
and then worked it back onto the motor for a tighter fit.
I applied a little silicon heat sink paste for good thermal
conductivity between the tube coils and the motor. I would
not even run a motor in any boat without some sort of cooling
solution. After a run I can hold my hand on one of the motors
indefinitely, they are only lukewarm warm. The brush hoods
get mighty hot, but at least you are not thermonuking the
magnets. This mod gives a perceptible increase in speed, run
time, and motor life.
Do not use a standard servo for steering. I was amazed
at the difference of putting in a slightly beefier servo.
I guess there is more load on those outdrives than one would
expect. The servo I have in there is not terribly fast but
it does have 46 ounce inches of torque. This mod (not really
a mod as the kit doesn't have a servo in it) improves drivability
and handling.
I went through speed control after speed control trying
to find a way of keeping them dry and cool. This is a tall
order for any electronics in a wet environment. My first attempt
was with an old Tekin 310 inside of a homely, water tight
plastic box. This did not work at all, as it always went into
thermal shutdown, and twice failed entirely. I got serious
and purchased a Zeta (I think that was the name of the company
...?) water tight speed controller. This thing was BURLY.
The case was machined out of a solid piece of aluminum. It
had reliability issues, was a low frequency controller, and
I got crappy run times with it, so back it went. Then I placed
a brand new Tekin 411G inside a Novak water tight case (don't
even ask how I pulled that off !). This worked very well for
quite some time... but then Tekin came out with the
TSC432M (M for Marine). This is the controller you see here.
Don't even consider anything else .. 'nuf said.
The silver looking box is actually section cut out
of an organizer box (hey what can I say, it works). The silver
is from the aluminum foil on the inside, surrounding the receiver.
I use a standard Tekin FM receiver. The foil is an extra precaution
against RFI. I don't know how much the foil helps, but I can
control the boat when it is farther away than I can see. Once,
trying to see how far I could get it to go, I sent my brother
out in a dinghy (small boat) to chase after it. He had to
stand up and point to me which direction to steer so I could
get it back, as it was so far away I could not tell what it
was doing. This mod improves usability and, in some cases,
safety.
The weird looking cross brace thingy just in front
of the steering assembly is a stopper for the servo arm. Occasionally
after a bad crash one of the universals would be broken. I
figured this was due to the outdrives slamming over so hard
that the universals were angled sharper than they could function,
causing them to break. The stronger servo helped, but the
stopper assembly alleviated this problem entirely. The servo
arm cannot rotate farther than the stopper posts, so I set
them to restrict the angle of the outdrives to less
than the maximum angle the universals can handle. This mod
improves reliability. On the topic of the steering assembly,
I installed a much longer arm on the servo and placed the
ball studs under the arm. This enhances the geometry quite
a bit.
The electronics are all mounted on yet another fiberglass
plate. This is just a cleaner layout if you don't use the
included mechanical speed controller. Hull flex is reduced
as a side benefit. I mounted the speed controller's on/off
switch inside the boat on a custom bracket I made. I actually
hate this modification as I always forget to turn it on until
after the top is screwed down.
I replaced the factory shaft tubes with larger diameter
tubes so that I could install 4x8 flanged bearings in them.
The motor mount hole for the shaft tube and the transom penetrations
had to be drilled a bit larger. The factory motor mount placement
markings (the little bumps telling you where to place the
mounts) are quite a bit off. If you use the template, the
mounts will be skewed and not be aligned properly with the
holes in the transom. I found this out after placing the mounts
on the vertical motor plate I made, which forced a proper
alignment. Just ignore the factory template and use your eyeballs
to sight it in. Place close attention to the little plastic
pieces under the motor mounts ... they have a front and back.
Once the hull pieces are glued, you are toast.
Picture 5
Here you can see the water pick up for the cooling system.
Traxxas' web page would have you place them elsewhere. I tried
it their way first and now feel my picture details a much
cleaner solution. The Traxxas recommendation fails for 3 reasons:
(1) the pickups are too far forward and are not ever in the
water doing their job when the boat is at high speed, (2)
you have to penetrate two flexible hull pieces with a solid
tube in two places (just try keeping them in there with any
amount of glue), (3) there are two friction points. The big
boats place the cooling pickups in the rear for a good reason...
I have found that having the pickup almost completely out
of the water works great (reducing drag even further). I use
the supplied T-tube to split the one water input into two
feeds for the motors. The path is: into the pickup, through
the speed controller, through the T-tube, through the motor
cooling tubes, and out the sides.
As an experiment I moved the outdrive linking bar to
a lower spot on the outdrives. I did this to reduce flexing.
While the flexing was greatly reduced, at least when forced
by hand, I noticed no in water difference.
Replacing the stock props with Octura X447 props was
one of the biggest enhancements. One is a right hand and the
other a left. I recommend the Beryllium units even though
the picture shows the aluminum version. I had beryllium props
and lost one in the drink. When I went to the shop to get
a replacement all they had were aluminum ... The aluminum
units dent real easy. I noticed no difference in performance
even though I expected to (because the beryllium props are
way heavier). The prop cones are a nice finishing touch but
I doubt there is any major performance enhancement here.
One thing I learned right off was to use Loctite threadlocker
every where. A dab on the main spur gears, from the main shaft
to the universal, from the universal to the prop shaft, and
the prop shaft to the prop collar (only if using the Octura
OCGCSS prop shaft adapters and X447 props). The Octura prop
shaft adapters do not come with a flat side to secure the
grub screw to. I Dremeled one in there before applying Loctite.
I run the trim set all the way out and wish it would
go even further. Less trim is great for low speed handling
and turning, more trim is better for high speed running as
there is less boat in the water. It is an interesting setting
to fiddle with because it can dramatically alter the boats
handling characteristics.
I had a difficult time drilling out the outdrives for
bearings and was only marginally successful so I reverted
back to bushings to be safe. I think the outdrives were weakened
too much by drilling anyway. Proper alignment seems to be
the biggest problem. The bushings work great if lubed regularly.
The reason for the different colored universals on
the outdrives is because I broke one of the stock units
and replaced it with one from Graupner. The Traxxas units
are out of round a little, causing a click click when the
prop is spun slowly and a roar when spun at normal operating
Rpm's. This could be due to manufacturing tolerances because
some of them did not do this.
Summary
The priority list for upgrades and modifications looks something
like this:
1) Stabilize the motor mounts some how
2) Get good quality waterproof speed controller (Tekin 432M)
and waterproof the receiver and steering servo (bathroom silicone
sealant works amazingly well)
3) Find a good motor cooling solution
3) Replace the propellers with Octura X447 units (one right
hand, one left hand rotation)
4) Get a good quality medium to high torque servo. Speed is
not important for this application. Be sure it fits in the
radio tray, however
5) Replace the motors with a budget mod (cheaper) or a Reedy
Sonic (stronger faster better costlier) stay above 16 -18
turns for small comm motor and above 14 for a Sonic). You
may want to get smaller pinion gears for the low side
of this range.
6) Bearings (be sure that they are constructed entirely of
stainless . The first set I had rusted out)
7) All the other stuff I mentioned
This seems to have turned into a review more than anything,
against my original intention. I may have sounded a little
down on Traxxas. I think that some parts of the kit need serious
improvement, while the kit as a whole is a great piece of
work. My wish would be to turn the presently available kit
into a beginner model, release another version with no electrics
at all, improve some of the things I've mentioned here, and
sell it for the same price.
Some of the mods I discussed here are absolutely necessary
for reliability and over all fun. Others are for the speed
freak and psycho tweaker. I would not expect to see the latter
incorporated into the kit, but the average user will have
a tough time even keeping this thing together in it's stock
form. This statement has been qualified by others who have
purchased this kit at my recommendation and left it bone stock.
I have had years of fun with this boat and think it is better
than most kits in this price range (I usually see it between
$125 and $150).
Update: 1/26/07
I no longer have a
Traxxas Villain, but plan on getting one again. Probably the
new Villain
EX version.
Since this article was written, 6-7 years ago, I spent quite
a bit of time with it and did a few things to make it faster,
but nothing too different than what is listed below, so not
worthy of updating the info. Mostly just updated motors and
batteries.
But I do have updated pictures and movies (see sidebar).
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