RCU Review: DuraTrax RT-X 27

RCU Review: DuraTrax RT-X 27
 RCU Review: DuraTrax RT-X 27 More On This Product
Discussions on this Product Show user ratings Check for Retailers Contributed by: Michael Lawlor | Published: August 2008 | Views: 64911 |
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Review by: Michael Lawlor
Under The Hood
Required Items
Included Items
Prep Work
Driving Impressions
Photo Gallery
Manufacturer Info
Distributed by Great Planes
Model Distributors
PO Box 9021
Champaign, IL 61826
Website: www.duratrax.com
Duratrax recently added another monster to it's arsenal of
vehicles with the release of the RT-X 27 nitro truck. The RT-X is
an evolution of the Duratrax Warhead and Warhead EVO with
the upgrades customers have been asked for such as a forward
only transmission, lighter truggy style wheels, 3 shoe racing
clutch, and steel spur gear. Read along as we open this bad boy
up and find out what it's made of. RT-X 27 Video
-Durable Suspension
-Modular Design
-2 Speed Transmission
-Strong brakes
-Tight Factory Gear Mesh
-No Threadlock on Spur Gear
-Weak Kwik Pit Starter Gears Model: Duratrax RT-X 27
Part Number: DTXD71**
Price: $399 street
Length: 22.375" (568mm)
Width: 17" (412mm)
Wheelbase: 14.375" (365mm)
Ground Clearance: 3.75" (95mm)
Weight: 10.8 lbs (4.91 kg)
Engine: SuperTigre G-27 CS .27 (4.4cc)
Exhaust: Dual chamber polished aluminum tuned pipe
Brakes: Dual composite disk
Clutch: 3 shoe
Transmission: Posi-Shift 2 speed forward only w/slipper clutch
Differentials: Sealed F/R planetary metal gear
Driveshafts: Steel CVD (Constant Velocity)
Wheels: 8 spoke truggy
Tires: Truggy pin spike
Hubs: 17mm
Fuel Tank: 5.6oz (165cc) with flip top cap
Radio Transmitter: Duratrax/Futaba 3 channel AM
Radio Receiver: Duratrax/Futaba 4 channel AM
Steering Servo: Duratrax SX200 high torque metal gear
Throttle/Brake Servo: Duratrax SX100 standard
6 Cell battery and charger Nitro fuel 20%
Glow plug igniter
Spare glow plugs
Glow plug wrench
Phillips head screwdriver Small flathead screwdriver Needle nose pliers
12 AA Alkaline batteries
Fuel filler bottle
After run oil
Assembled model
Radio system w/servos
Kwik-Pit electric starter
Engine tuning DVD
1.5mm hex wrench
2.0mm hex wrench
2.5mm hex wrench
4 way wrench
Camber link wrench
2 tubes air filter oil
Owners manual
Exploded parts diagram
RT-X 27 Chassis
The RT-X 27 comes ready to run (RTR) from the factory including a 3 channel Futaba made radio system,
and Duratrax's Kwik Pit Super Start system. It includes a nicely detailed lexan body which comes screen
printed in six different color combinations. For our test we chose red though if you're planning on running
the RT-X with your buddies you may want to choose different colors as each corresponds to a specific radio
frequency. Front Suspension
Side of Chassis
Never mind everything else, lets get to the heart of this thing, the engine. The RT-X is powered by a 2.5HP
SuperTigre G-27CS engine. Although the G-27CS shares the majority of it's parts with the Warhead's
engine (G-27CX) it has been upgraded with a more durable pilot style SG crankshaft. Another difference
between the two is that the RT-X includes the Kwik Pit backing plate rather than the regular pullstarter
included with the Warhead. As with both engines the CS has a dual ball bearing supported crankshaft which
like the rest of the engine is covered under a three year warranty. Chassis Top View
Tuned Pipe
Front Bumper and Suspension
The G-27CS is fed it's breakfast of fuel and air through a SuperTigre slide valve carburetor, which is then
compressed by a true ABC construction piston/cylinder, and finally ending up screaming it out through a
polished aluminum dual chamber tuned pipe. All that commotion creates a lot of friction and heat and to
counteract that Duratrax chose to install a machined aluminum ten fin anodized heatsink head. Sometimes
it's the little things that count and this time Duratrax got it right by adding a simple clamp on the fuel line
which makes for easy cutting off of the engine. No more need to burn yourself on the exhaust outlet!
One thing we wanted to point out is the clutchbell to spur gear mesh was set extremely tight and we could
barely turn the clutchbell by hand. The solution was to loosen the four engine mounting screws and
properly set the mesh. In the end it wasn't a big deal but we wanted to point it out because it could have
easily turned into a larger problem had we note found the problem early. Be sure to check your gear mesh
before running your RT-X for the first time.
Fuel Tank
Fuel Cutoff
The true beauty of the RT-X is in it's modular design. Everything from the lower suspension arms, to the
differentials, diff cases, shock towers, and more are interchangeable front to rear. That means when you
bend a hinge pin or strip a pinion gear you no longer have to look for for a front or rear specific part.
Instead you can use whatever spares you have laying around. Another great feature of the RTX's design is that the entire front or rear bulkhead can be separated from the chassis with
just three screws on each side. The ease of maintenance with a design like this is incredible. As you'll read later on we
had to disassemble this truck a few times and the modular design really came in handy.
Race Mode
Rumble Mode
Modular Design
We were pleasantly surprised at how well built the suspension was. It is based around eight extra long oil
filled coil over shocks which are made of polished aluminum and offer a threaded upper portion which
allows a large amount of pre-load adjustment. Duratrax must have been having a good day when they built
the shocks because they're real works of art. They come pre-assembled with rubber boots around the
shafts for long o-ring life and took all we could throw at them.
Speaking of suspension adjustments the RT-X is king in that arena. Duratrax wanted to satisfy all comers so
they designed the RT-X so you could have the best of both worlds. In what they call "Rumble Mode" the
truck sits up real high so you can tackle all sorts of terrain without the worry of bottoming out or getting
stuck. On the other hand in "Race Mode" the RT-X is low slung, sleek, and ready to race. With 63 possible
shock mounting combinations you can set the ride height anywhere in between to suit your needs. We
found that dropping the truck almost to it's lowest setting yielded the best handing for our tests.
Along with all of those shock positions the RT-X also has numerous other suspension adjustments that can
keep you occupied for days. For example the upper arms have two available mounting positions for roll
center adjustments and Duratrax even supplied steel turnbuckles all around.
Ready to Run
Windshield Before
Windshield After
The RT-X 27 comes assembled, body painted, and tires installed. In all reality there isn't much to you need
to do to get it running. However there are a few little things you need to prepare for before hitting the
track. Although the body is already trimmed you will need to get out your favorite body trimming scissors to
cut a hole in the front windshield.
Duratrax only recommends cutting a hole in the windshield to provide cool air to the engine, but we
strongly suggest also cutting out the entire rear window. Not only will it contribute to the airflow over the
engine's cooling head but it'll give you access to the rollbar/carrying handle. Along with cutting the windows
you'll also need to cut a small hole through the windshield decal for the antenna.
You may have noticed that we didn't include the decal sheet in the "Included" section above. That is
because our vehicle came with the decals pre-installed. Personally that is the way I'd like all my vehicles to
come but if yours doesn't then you'll need to take the time to carefully place them on yourself.
Rear Window Before
Rear Window After
Four Channel Receiver
Once you've got the body trimmed all that is need to do is set up the radio system. The RT-X 27 comes
equipped with a three channel AM radio made by Futaba. Originally Duratrax decided to go with a 3 channel
unit because the RT-X's predecessor, the Warhead, used the third channel for reverse. However the RT-X
has a forward only transmission so the third channel is not used. If you're like me I'm sure you'll find
something to use it for in the future. Snow plow anyone? Oddly enough the transmitter is a 3 channel unit while the receiver has 4 channels. Anyway, back to
getting your vehicle on track, all that is needed to get your radio system up and running is to install the
antennas, and put eight AA batteries in the transmitter and four in the receiver pack. Although the supplied
receiver pack will work for now you may want to consider going with a five cell rechargeable pack in the
One final thing you need to do before running your beast is to oil the air filter. Duratrax supplies two tubes
of air filter oil which should last you a little while but sooner or later you'll need to stop at your local hobby
shop to pick up some more. Lubricating the air filter is quite simple. The easiest way we found to do so is to
place the filter and oil in a zip lock bag and then work the oil over the filter until it looks evenly covered.
After about every five tanks of gas you'll need to remove the air filter from the vehicle and clean it with
warm soapy water and re-lubricate it. You're ready to blast off....well not quite.
High Torque Servo
Engine Access
As with all nitro vehicles the RT-X 27 requires a break in period. It's absolutely imperative that you break in
the engine exactly as the manufacturer recommends so you get the utmost power and life out of your
engine. Duratrax recommends a five tank break in period in which you start with the factory needle settings
(High:4 1/2 turns and Low:12 1/2 turns) and each tank you lean out the high end needle by 1/12 of a
turn. After your fifth tank is over then you can slowly start tuning for performance.
Speaking of starting the truck we were extremely glad to see that Duratrax included the Kwik Pit Super
Starter system on the RTX. All you need to do is install an ordinary 6 cell battery pack (not included) in the
Super Starter, attach the starter to the backing plate, and hit a button. The Kwik Pit starter does all the
work for you. Now it's time to blast off!!!
After breaking in the G-27CS I was eager to start leaning it out to see what the RT-X has in store. On my
sixth tank of fuel I ever so slightly leaned the high end needle and ran it back and forth to get the engine
up to operating temperature. At that point I wanted to do the good old pinch test to see where the bottom
end was set. For those who aren't familiar with nitro engines, or have just never heard of the pinch test I'll
try to explain. To perform the pinch test you literally need to pinch the fuel line going from the fuel tank to
the carburetor while the engine is at idle. Then depending on how the engine responds you will know how
well the low end needle is tuned.
If the engine immediately slows down that is a sign that your engine isn't getting enough fuel and you need
to richen (counter clockwise) the low end needle a little. On the other hand if the engine speeds up and
stays that way for more than four seconds its a sign your engine is getting too much fuel and you need to
lean the low end needle. (clockwise) What you're looking for is for the engine to speed up for 2-3 seconds
and then slow down, that is a sign that your low end needle is set properly.
As for the high end needle the more lean you make the mixture, within reason, the faster your truck should
be. However leaning the high end needle will also cause your engine to run hotter. In the end what you
want is a good compromise between speed and engine temperature, hopefully with the engine running at
less than 270 degrees. If all of this sounds confusing don't worry, Duratrax has included a DVD which
explains it all to you in detail.
Once we got it tuned it was time to see what she had. For our test we chose to run the RT-X 27 where we
believe the majority of buyers will, in the back yard, and on the street. Sure we could have went to the
local track and told you how great it takes the table tops and doubles but that isn't going to mean much to
the average enthusiast. Instead we wanted to test it in real world conditions.
For the first run I took the RT-X to my back yard to see how well it does on tall grass, and over the rough
stuff. At first I noticed that the RTX's steering seemed sloppy and loose. It felt as if I had to come to a crawl
before it would even try to take a turn. After looking things over I found a quick tightening of the servo
saver solved the problem. If you experience the same you can easily tighten the servo saver by turning the
silver adjustment knob from underneath the vehicle. We also decided to move the steering links to the rear
most position to give it even more steering.
With that sorted the truck was a blast to drive. We had set up a few wooden ramps to see how the RT-X
reacted to getting airborne and I'm glad to report it soared through the air like a bird. Unlike most trucks of
its size the RT-X didn't have a tendency to get squirrelly in mid air. On the rare occasions that we hit a
jump too hot a quick tap of the brakes would pull the nose back down. Due to the RTX's super plush
suspension landings were a dream. There wasn't one time during all of our testing that we noted any
bottoming out of the suspension, nor did we break anything after many hard landings. We tried the RTX in both "Rumble" and "Race" modes and found out the obvious, Race mode just plain
handles better. In Rumble mode the truck felt loose and tippy. On pavement it would easily lift the inside
front tire when turning. In Race mode the truck felt much more planted and didn't exhibit nearly as much
body roll as when set to Rumble mode. Some buyers may opt to run their truck in Rumble mode for the
extra ground clearance but even when run in Race mode we had no problems with getting stuck on
anything. Personally I can't see much reason to use Rumble mode, though I suspect some may set it that
way purely for that monster truck look.
After our second tank of fuel we stopped the engine to allow it to cool and prepared for our next run. Upon
trying to start the engine we heard a horrible grinding noise coming from the engine that we feared was an
expensive engine problem. Subsequent disassembly isolated our problem, stripped gears in the Super Start
backing plate. A quick call to Duratrax got us a new gear set plus a theory on the possible cause of the
stripped gears. According to Duratrax if the engine is flooded the Kwik Pit system is so powerful that it can
sometimes overpower the gears in the backing plate resulting in them stripping. It's hard to say if that was
the cause of our stripped gears but thankfully it hasn't happened again since. Unfortunately while taking the vehicle apart to replace the stripped gears we found it didn't look as though
threadlock was used on the tiny screws that hold the steel spur gear ring to the aluminum hub. What must
have happened at some point during a first couple of runs is a few of the screws backed themselves out
and were lost. The lost screws weren't all that big of a deal, but they did wear on the transmission some.
You can bet that we used about a gallon of threadlock on those screws this time!
After finally getting everything back together we started her up and went for a spin on a local dirt road. We
had already gotten a feel for what the RT-X can do when jumping but we wanted to see what it could do in
the speed department. Without access to a radar gun there are two methods to get real top speed data
from an R/C car. The first method involves taping an expensive GPS unit somewhere on the car to record its
top speed, however this method isn't always accurate and I wasn't too crazy about putting my expensive
GPS unit in harms way. Instead I chose the second method which involves timing how long it takes for the truck to go through a
pre-determined speed trap. A little math and you've got your top speed. After running the truck through
the speed trap numerous times we were able to muster a decently fast top speed of 36.91 mph. Not bad
considering we didn't mess with the 2 speed and the test was conducted on a dirt road. Even on such a
slippery and bumpy surface the RT-X handling the high speed runs with ease. Don't be fooled though, this
baby packs enough speed that if you get a little sideways it'll take a good bit of driving to reel her back in. Stripped Gears
Transmission Damage
Missing Screws
High Bandwidth | Low Bandwidth
The RTX isn't without problems. If it weren't for a few loose spur gear screws and a set of stripped
gears I think I could say the RTX-27 is darn near perfect. However the stripped Kwik Pit backing
plate gears is a real downer because it makes me uneasy each time I attempt to start the vehicle. I'd
really like to see Duratrax either beef up those gears or possible run some type of clutch on the unit. The upside is that due to the engine location you can still use a starter box if you like, something I
think should seriously be considered if you are planning on buying this truck.
On the other hand the RT-X features a plush yet beefy suspension that soaks up everything that is
thrown at it. There were a few times when the it hit a jump a little sideways and landed at awkward
angles on the front suspension arms and without so much as a hiccup the RT-X took the punishment
and kept on truckin'. The RT-X is one tough puppy.
Distributed by Great Planes Model Distributors
PO Box 9021
Champaign, IL 61826
Website: www.duratrax.com
Comments on RCU Review: DuraTrax RT-X 27
Posted by: warheadforever on 08/03/2008
Profile Hello, it is Warheadfoever,I have a Warhead EVO, and would like to know if you have had any problem with the shafts
from the tranny to the differential? I have had 3 set were out, and would like to know if Duratrax has fixed this
problem. Thanks Warheadforver
Posted by: drevil on 08/03/2008
Profile I never had one problem with the shafts. To be honest I don't know if they're the same as what came in
the Warhead but can say that I didn't experience any excess wear with them.
Posted by: webdr on 08/03/2008
Good review, great pics. Welcome aboard the review team! Matt
Profile Posted by: drevil on 08/03/2008
Matt, Thanks for the good words!
Profile Posted by: brianmarks78 on 08/04/2008
Profile Nice truck, but, bad video...The video doesnt show what the truck is capable of on the track, jumping and bashing..Im
a duratrax owner (raze/raze st/warhead)....Video is lame..boring.. good truck though. brian Posted by: Lilredmachine on 08/05/2008
Profile Was gonna say, the whole point of this truck is that it's meant to be raceable. So, it would have been nice to see
it on both the track and off road. Posted by: webdr on 08/05/2008
maybe there isnt a track near his house.
Profile Posted by: brianmarks78 on 08/06/2008
You right webdr, maybe he doesn't live near a track, my bad! But then why is he testing the vehicles????
Profile You right webdr, maybe he doesn't live near a track, my bad! But then why is he testing the vehicles????
Posted by: rcmadness09 on 08/07/2008
Profile I have ran this truck on a track against my revo and i can tell you this truck handles way better than my revo very lil
body roll at all and soaks up the hits like they weren't even there. A + to Duratrax The Rtx-27 is everything the
warhead wasn't then some.
Posted by: rcmadness09 on 08/07/2008
Profile The Rtx-27 is everything the warhead wasn't then some. I have raced this truck against my revo and it just flat
out handles better and can suck up some mean hits like it was nothing. A+ to Duratrax its one mean racing nitro
Page: 1 2 > 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. EMAIL THIS ARTICLE OR CHECK OUT THESE OTHER GREAT REVIEWS!
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