prone to cracking *updated header currently under development*
tank cap leaks gas
something to be said about large scale gas powered boats; the
sound, the performance, the smell, the whole experience of operating
one at speeds that rival their full-scale counterparts brings
a smile to your face. And up until recently, you had to piece
together a gasser, ordering parts from a number of different manufacturers
and assembling the running gear, installing the motor and hardware,
only to discover your in for over a grand, any you haven't even
spilled any gas on your shoes! The whole process was something
you learned from experience rather than a set of instructions.
in the past few years, ready-to-run gas boats have hit the water
hard with the majority of them putting down some pretty impressive
numbers out the box. Their appeal not only comes from decent performance
but that they are truly ready-to-run; you don't have to buy anything
except for fuel and oil to have hours of fun on the lake or in
Aquacraft Models, a company with some well known nitro and fast-electric
hulls that recognizes the desire for large, high-performance rtr
gas boats. And their answer is the Rio 51. This
large scale gas mono is an exceptional choice for the budding
boater, the person looking to make the switch from nitro or electric,
or anyone wanting the gas experience without paying the full price.
Rio 51 was tested by myself, as well as a seasoned racer, and
a total newbie in an attempt to gauge the boat's good and bad
characteristics from different standpoints. Now, let's mix up
some fuel and test the Rio 51!
Rio 51 Price: $699.99 retail price Length: 51" bow to stern Beam: 13.5" Motor: Fuji-Imvac BT-28 Weight: 13.75 lb Receiver batteries used: NiMH hump pack (not included) Transmitter batteries used: 8 AA batteries Radio equipment: (Included) Tactic 2-channel FM transmitter,
receiver, throttle and high-torque steering servo.
head screw driver
and 2-stroke oil mixed @ 32:1
fuel container and pump
wrenches for running gear adjustments
scoop and engine head
tabs and adjustable surface drive
and water pickup
Rio 51 arrived at my door in a massive box that seemed to take
up half the living room. Even the dog was a little upset as this
cardboard behemoth invaded his favorite sleeping spot on the carpet.
I suggest opening it on the front lawn to keep your significant
other happy and the neighbors jealous. After chucking the shipping
box, your presented with yet another cardboard monstrosity, it's
contents proudly displayed in ink all over; make no mistake, this
boat is big. Pull the top off and you'll see the Rio nestled in
enough styrofoam to build a floating dock. The radio is in it's
own box tightly secured to prevent movement. I have a feeling
that even the roughest shipping company would have problems damaging
this hull! Before you throw all that packing away, cut a fist-sized
square of styrofoam and save it; you can then glue it to the bottom
of the hatch, effectively preventing the hatch from sinking if
it comes off in the water. Nice, huh?
at the stern, Aquacraft has given the Rio 51 black anodized Grimracer
running gear, thanks in part to designer Michael Zaborowski. On
either side of the transom are cnc-machined turn fins that can
pivot back if they hit something. They are fairly sharp and their
fit and finish is excellent. Slightly inboard of the fins are
the trim tabs. They are made of stainless steel and are adjusted
by bending them up or down. It takes some force to bend them so
you don't have to worry about them moving without you applying
the force. Exiting out the back of the boat, and slightly offset
to the right, is the black anodized aluminum surface drive. It's
drive angle is adjusted up and down by loosening the two hex-head
screws. This system is stout and makes for easy flexshaft maintenance
because only two screws need to be loosened to remove it. As with
the fins, the finish is perfect with no blemishes found anywhere.
Coming stock with the boat, and located at the end of the drive,
is a two-blade cast prop made of copper-beryllium-titanium. It's
a great-performing prop to get you in the water and an optional
three-blade prop (pictured below) is available for even greater
performance. The rudder, like the rest of the gear, is anodized
and quite sharp. It is held in place by a hex head screw above
a smaller phillips head screw. The smaller screw is designed to
shear if you strike something, thus saving the hull from severe
damage. It's also adjustable so you can tuck it in to keep the
hull planted when turning. Forward of the rudder is the coolant
pickup. This is where all the water is picked up for cooling the
engine and exhaust and it does a good job of doing so. Make sure
it is lower than the trim tab of optimal water pickup.
should be noted that Aquacraft has chosen to secure the running
gear to the transom with metal plates vs blind nuts. It looks
as if these plates are very strong and should be that added bit
of strength to prevent anything from cracking the glasswork.
the hull itself, you'll see the Aquacraft team has gone to great
lengths to create a high performance, as well as visually appealing
final product. The lines are great, the graphics look good, and
it handles a variety of water conditions extremely well. Starting
with the colors; your given a pallet of red, blue, or yellow which
sets the boats apart if you are running more than one. The graphics
consist of yellow, white, and black checkered flags towards the
rear and a few yellow "Rio 51" labels on either side
and on the deck. A decal sheet is included with a side-specific
number plate and numbers, Aquacraft logos, and a few Grimracer
logos as well. All of them look good on the hull but are a little
thin and the underlying hull color can be seen through them; this
made the white color on my checkered flag look almost pink. Was
this a problem? Not really, just worth noting. Aquacraft has made
sure the engine stays relatively cool by adding a total of five
air scoops on top of the hatch. These scoops coupled with the
engine and exhaust coolers do a good job of keeping everything
from overheating. The hatch is attached with a dowel up front
and two fasteners at the rear. It's secured by positioning them
parallel to the hull and pressing down, and released by turning
them 90 degrees. The fiberglass work on the hull is quite thick
and there were a few guys at the lake that were interested in
testing it's strength; they pulled it and pushed it with just
enough force to satisfy their curiosity.
Flexshaft oiling system
chose to outfit the Rio 51 with a Fuji-Imvac BT28 marine engine.
It's a water cooled 28cc 2-stroke with enough power to swing the
large props available for the Rio and push it into the low 40s.
The motor is secured to the hull by four rubber isolators that
reduce vibration and the twisting caused by torque. Starting the
Fuji is accomplished with a pull starter similar to any trimmer
or blower and the system worked as expected throughout testing.
The carb is a standard Walbro 257 with a manual choke and features
a high speed and low speed needle. Information pertaining to tuning
the carburetor is included with the Rio and is explained in plain
english for all you first-time gas boaters. The Fuji is cooled
by a water jacket on the head, exhaust flange, and at the base
of the tuned pipe. Water is picked up at the rear and pushed forward
to the head, then to the base of the header, then to the pipe,
and is expelled out the left side of the hull. Keep in mind there
is no water pump because the forward motion of the boat pushes
water through the system starting at the pickup tube.
is expelled from the engine through a "wrap-forward"
style header common on deep vee hulls. The tuned pipe slides over
the header and is held snugly with two o-rings that prevent it
from moving around and keeps the cooling water from entering the
pipe. The pipe exits the hull at the transom which is fitted with
a flanged rubber tube to reduce vibrations and prevent any damage
to the hull. The header is made of stainless steel and has proven
to be the one weak link in the Rio 51's outstanding setup. Mine
cracked at the base after a few tanks of running. This problem
has manifested itself on a few other boats and Aquacraft has taken
the steps to redesign the header. A new and improved header is
being manufactured as I type and should be available very soon,
so I've been told. The tuned pipe as dubbed a "quiet pipe"
and effectively keeps the decibels down around 80db which shouldn't
cause too much static with the neighbors ...notice I said "shouldn't."
gas tank on the Rio is a hard plastic tank with a screw on cap.
The cap has a small hole in the top for ventilation. I
found after long runs the breather hole on top of the cap is allowing gasoline to
exit the tank. It's
not much, but after a long run you'll see a thin coating of fuel on top.
I installed a standard fuel nipple and fuel tubing to the top of
the cap which I hoped would allow ventilation and stop the fuel
from escaping. Unfortunately, the problem is with the cap
itself as it does not have a gasket to seal it completely
tight. I will be looking for gasket that fits the cap and is
resistant to fuel to solve this concern.
Below and in front of the gas tank is the oil injection
tank for the flexshaft. This is a great little feature that allows
for a constant flow of motor-oil to the flexshaft for lubrication.
There's a hose clamp on the line for cutting the flow of oil when
your Rio is in dry-dock. Take note; the auto-oiler is in no way
a substitution for lubing the flexshaft with marine grease.
No blind nuts
box, receiver and servos
electronics included with the Rio 51 are decent; you get an FM
pistol-grip radio, a standard throttle servo and a high-torque
steering servo, and an FM receiver. The switch is mounted in the
radio box lid and is waterproof. Also included is a battery clip
that accommodated 4 AA batteries to power the servos but I chose
to use a rechargeable NiMH hump pack for longer run times. The
transmitter features servo reversing, trim, and steering dual-rate.
and there's also a red LED on/off light that will blink when battery
level gets low. My only issue is the lack of a charging jack,
which limits the transmitter to non-rechargeable AA batteries.
radio box made of hard plastic and does a great job of protecting
the radio gear. The lid, though, is nearly impossible to remove
without a screwdriver or something similar to pry off the clip.
Not really a problem but it snapped my finger once trying to remove
it by hand and left a nice mark ...I wont do that again! Radio
box seals are used where the pushrods enter the box. I experienced
no problems from the entire FM system and expect it to last for
a long time, even with the constant vibrations handed out by the
engine must be broken in like any nitro engine. The BT-28 is set
very rich from the factory and some needle adjustment might be
needed to get it fired up, depending on your location and outside
temperature. Per the instructions in the manual, run the Rio through
a full tank of gas at a somewhat rich setting before tuning for
performance. But before you crank her up, prepare the boat by
adding 4 AA batteries to power the receiver and servos and 8 AA
batteries to the transmitter. Don't forget to fill the auto-oiler
with motor oil and grease the flexshaft. There's a green clip
on the oiler tube that should be clamped closed before you put
any oil in it.
AMB and RCU member Will Nichols (Believe It) met me at the Atlanta
Model Boater's lake to test the Rio 51. Right from the start,
things went smoothly; the green clip on the flexshaft oiler was
opened to allow flow to the shaft and after a few priming pulls
with the spark plug cap off, the engine sputtered to life and
required a little throttle trim to stay running. With the needle
settings remaining untouched from the factory, it was evident
that the motor was running too rich as we tossed the hull into
the water for break-in. A little leaning of the high-speed needle
got the Rio almost on the pipe and we proceeded to finish break-in.
the Rio 51 is broken-in and tuned for performance, you'll soon
realize that it's a great hull and exhibits no adverse handling
characteristics. Will put the Rio through the ringer but was unable
to capsize the hull, but don't think it's invincible; introduce
some heavy chop and you could get it to grab in a turn and roll.
Full speed left and right hand turns are possible, as evident
in the video, and make for a nice show as it digs in and throws
a few buckets of water. Even though left hand turns are easily
accomplished, the Rio 51 does best when turning right due to the
placement of the rudder and the counter-clockwise rotation of
the propeller. Although we were in a small lake, we were able
to make some decent wake by running in a circle, creating a washing
machine effect in the middle. Hitting this wake almost always
got the Rio 51 airborne and it repeatedly landed smoothly and
kept on going. As far as attitude, the Rio 51 was close to perfect
from the factory. I added a slight bit of positive angle to the
surface drive and maybe 1 degree of positive to the trim tabs
to pull the hull out the water up front. In my opinion, this seemed
to wake the hull up a little and got it moving well.
Fuji-Imvac BT28 motor supplies the Rio with enough power for the
new gas-boat enthusiast, or anyone just looking for high-performance
boating. It provides speeds around 40 mph with the optional 3
blade prop which is just fast enough so you don't have to worry
about it getting ahead of you. Throttle response is crisp with
no lag and the torque is sufficient. The exhaust note is not as
sharp as an aluminum tuned pipe, it's definitely more mellow and
should allow you to run in public lakes but remember to always
respect others when running your boat in public; what's music
to you may not be so with others.
only problem I encountered with the Rio 51 was the stock header.
The weld around the flange is weak and prone to cracking as did
mine only after 2 tanks worth of running. I'm pretty sure the
vibrations, weight of the pipe, and the weak welds all played
their parts in killing the header. Note that Aquacraft is fully
aware of the problem and is taking the steps to correct it. After
contacting them about the casualty, I had a new header at my door
in a few days.
couple of things to watch when running your Rio 51; Always make
sure there is water exiting from the coolant port on the left
side of the hull and get in a habit of looking for it every pass.
Doing so will ensure adequate cooling and will keep the Fuji happy.
Also keep in mind that even though the Rio is fitted with a flexshaft
oiler, remove the flexshaft after one or two sessions and re grease
the shaft. Last, charge or replace the receiver batteries after
every session to ensure a happy experience next time out. This
is where a receiver pack makes sense.
The Rio 51 is a
great entry level gas boat that exhibits exceptional performance
for it's class. The hardware and hull are top notch and the engine
is a good mix of economy and power. Aquacraft also gets an A+
for an easy to read instruction manual that guides you through
break-in and tuning as well as maintaining your Rio 51. Although
the test boat suffered from a broken header, I feel that once
Aquacraft gets the new design out, the Rio will be a flawless
boat for the beginner or anyone looking for real gas power at
a price that wont break the bank.
Models/ Great Planes Model Distributors P.O.
Champaign, IL 61826-9021
Web Site: www.aquacraftmodels.com
to Will Nichols (Believe It) for helping me test the Rio 51.
The comments, observations and conclusions made in this review are solely with respect to the particular item the editor reviewed and may not apply generally to similar products by the manufacturer. We cannot be responsible for any manufacturer defects in workmanship or other deficiencies in products like the one featured in the review.