Rampage XT RTR 1/5 scale monster truck

There are two things most guys like. "BIG & LOUD"! The Redcat Rampage XT offers both of those. While the chassis is like the Rampage XB-E, adding the large tires and huge truck body make the Rampage XT seem much bigger.

The Rampage XT uses the same heavy duty chassis as the Rampage XB-E. The beefy aluminum bottom plate and shock towers provide plenty of back bone strength and the plastic roll cage protects the components. The roll cage is constructed in sections and screwed together allowing easy access to different parts of the vehicle without having to remove the entire thing.

Wheels, tires, and drive train

The large monster truck tires are glued to black plastic rims. The deep directional treads should grip the terrain with ease.

The metal drivetrain starts with a four gear single speed transmission that transfers power to the center spool. The center spool directs the torque toward the front and rear of the truck through heavy duty steel dog bone drive shafts.

The power then reaches both front and rear oil filled differential units which consist of two bevel gears and two planetary gears. Two planetary gears are used instead of four. This allows the two gears to be very large for added strength and durability.

Large steel dog-bones then transfer the power to each of four wheels. Dog-bones are used in the rear and CVDs are used in the front for minimal binding.

Engine:

The Rampage XT is powered by a 30cc Fuelie 2-stroke engine with heavy duty centrifugal clutch. The spring loaded clutch uses two composite pads that transfer power to the vented clutch bell.

The single venturi carburetor uses a manual butterfly style choke like the ones found in hand held grass trimmers. The choke is easily adjusted using the large black handle.

High and low speed fuel mixture needles enable the operator to fine tune the 30cc Fuelie. The high speed needle is easily accessible but the low speed needle is blocked by the plastic roll cage. A rubber fuel primer bulb is located on the top of the carburetor to make starting the Fuelie easy.

A two stage foam air filter provides protection against dirt and debris. A red kill switch with water resistant rubber shield is mounted next to the pull starter providing means of starting and stopping the engine in one central location.

A plastic roll cage protects the engine and H-CMR5 INT® spark plug from damage. To remove the spark plug four screws must be removed from the roll cage to allow clearance.

A 500cc gas tank is mounted behind the engine and is waiting to be filled with a mixture of two stroke oil and unleaded gasoline. A mixture of 20-1 is used for break-in and a mixture of 30-1 can be used once the break-in process has been completed.

Suspension

The suspension design consists of a lower H-Arms and upper adjustable links which are made of generous amounts of plastic. Providing smooth suspension action are four adjustable oil filled threaded body metal shocks. Sway bars help keep the chassis stable and reduce side roll through cornering.

The shock towers are thick aluminum with a plastic facing. I'm not sure why the plastic facing was used but it does look cool. The shock towers offer a couple different mounting choices as do the H-arms. This allows tuning of the suspension which changes bump handling characteristics. Shock mounting position also affects the way the vehicle feels through cornering.

Radio

The 2.4GHz radio system included with the Rampage XT runs off eight AA batteries and includes functions such as servo reversing, steering and throttle trims, steering dual rates, and a bind.

A receiver box in mounted to the left side of the aluminum chassis and houses the 2.4GHz receiver, receiver battery pack, and on/off switch. The switch lever is accessed from outside the receiver box on the front. Padding for the receiver is not included and I highly recommend fitting some foam around the receiver and battery pack to avoid failure.

The Rampage XT is fitted with a fail safe device which is also stored in the receiver box. The fail safe is easy to set and will protect against frequency failure most likely due to run down transmitter batteries or driving out of range. The fail safe should be used inline with the throttle servo so when connection is lost the brake will be applied.

A huge steering servo, measuring 2.5" across (NOT including mounting tabs), is used to control the direction of the large front tires and is protected by an adjustable servo saver.

A standard size servo is used to control throttle inputs as well as braking inputs. The servo is held in place with four screws and uses a standard two blade servo horn.

Preparation:

The Rampage XT needs to be broken in before the real fun can take place but before anything, the receiver battery needs to be charged.

I plugged the receiver battery into the included charger the night before I planned testing the Rampage XT. By morning the battery was fully charged and ready to go.

The receiver tray offers plenty of room for the receiver and battery pack but offer little shock resistance. I cut some black foam I had stored for this reason and fitted it into the receiver tray to safely secure both the receiver and battery.

I then installed the fail safe inline with the throttle servo and set it the apply brake in case of an emergency. After testing the fail safe and performing a radio range check I moved on to oiling the air filter and mixing the gas.

I already had some unleaded gasoline, 2-stroke oil, and a funnel for other gas vehicles that worked nicely for the Rampage XT. I mixed the recommended 20 parts unleaded gas to 1 part oil for the break-in process.

I primed the engine using the prime bulb, closed the choke, and gave the pull chord a couple tugs. The engine fired once signaling me to open the choke and pull again. Quickly the Fuelie started up and idled smoothly. I let the engine idle through the half of the first tank of gas only having to restart the engine twice. Idling through 250cc of gas felt like forever and was close to it. For the remainder of the tank I drove the truck around the yard at 1/4 throttle.

The next two tanks of gas were used up at the park while fluctuating from 1/4 to 1/2 throttle. I continued using a fuel mixture of 20 parts gas to 1 part oil for all three tanks.

On the third tank I tried giving it a little more throttle but anything over 1/2 throttle caused the engine to bog as if it was starving for fuel. The instructions say the engine will not need to be tuned and the factory settings will be fine through break-in and beyond. I disagree.

The low speed needle was set correctly but the high speed needle was set too lean. I came to this conclusion by closing the choke half way and giving it full throttle. As the choke restricted the air flow, the truck ran better at full throttle but sputtered at lower throttle inputs wanting to stall.

I then richened the high speed needle 1/4 turn allowing more fuel to flow while in the upper throttle range. This completely remedied the situation and the engine began winding up to the expected RPMs at full throttle. The Rampage XT is now running good I am ready to have some fun.

Performance & Handling

I wanted to test the Rampage XT somewhere that would accommodate its large size and perhaps offer a challenge. I had been to a place called "Wheelin' in the Country" down in Summertown when I had my full size Jeep and dune buggy. This place offers 800+ acres of trails, hills, rocks, mud, and just about anything you would want to run a 4x4 or ATV through. Of course all I needed to use were the few acres of dirt and mounds near the entrance.

Well, I've got a 1/5 scale gas powered truck already broke-in, permission to run on worthy terrain, my camera crew, and a full tank of gas. Let's rock!

The Rampage XT started easily and calmly idled while I put the massive body on and fastened the clips. A little blip of the throttle and the clutch engaged sending the truck on its way. The ground was dry and dusty from a lack of rain which sent clouds of dust in the Rampage's wake. Although it created a slight problem for the camera crew, it looked awesome!

The dust just billowed off the large monster truck tires as if it were setting fire to the ground. At times the truck was hidden from sight because of a thick dust cloud but a gentle breeze soon provided visibility.

It's necessary for added air filtration while running in such dusty conditions. This can be accomplished by taping an additional large foam element, found at an auto parts store, around the entire air filter unit. This is cheap and easy insurance for your engine and is recommended.

The truck is stable in all situations. From all my testing, I didn't even roll the truck once and my testing included high speed cornering on a multiple of surfaces as well as some jumping and hill climbing. The Rampage XT has a low center of gravity which makes for stable handling.

Turning the Rampage XT was a blast in the dirt. The loose surface allows the rear to swing around half way through the turn allowing tight turns and much fun.

Turning on pavement proved to be a different experience. The only way the truck would turn sharply was off throttle or full on. Low amounts of throttle coupled with a high traction surface would cause the steering servo to center out some which created a large turn radius. Turning at low throttle was still very possible, but not near as sharp as I would expect from such a large servo. A more powerful receiver battery pack may remedy this but I did not have one in my possession so I am left unsure. I just pegged it half way through the turns and the wheel spin would help send the truck through the remainder of the turn.

Acceleration was great on any surface. The engine was responsive with only slight hesitation while pegging the throttle from a dead stop. This was later remedied with a bit of tinkering on the low end needle. From that point on the engine wound out great with next to no hesitation.

The single speed transmission quickly sends this truck to a respectable top speed. The Rampage XT can be driven in a mid sized yard but prefers to have some extra breathing room to stretch its legs.

Stopping the Rampage is a breeze. The double duty disc brake locks the tires with ease. It is a little tricky finessing the brakes to keep them from locking up. Once large amounts of dust entered the braking mechanism, they wanted to lock up without any brake input from me. This was slightly irritating and as you can imagine this caused the clutch to heat up quickly which showed in the body. I put full blame on the excess dust and debris. All other testing grounds like pavement and grass did not introduce this problem. After a good cleaning and some adjusting, the problem stopped.

The exhaust from the engine blows directly on the rear of the body quickly warping it and over a prolonged time, greatly distorted the tail gate. I decided to cut out the rear of the truck body to allow the exhaust to escape hoping this would help. I believe I will also need to install some 45 degree exhaust tips to direct the flow of heat beneath the body.

The Rampage XT has decent mid flight jumping characteristics, however the suspension bottoms out upon landing large jumps causing chassis slap virtually every time. It isn't good for a truck this heavy to be smacking the ground for obvious reasons so I am left with two options. I can either stay away from big air or beef up the suspension with stiffer springs and heavier shock oil. Replacing the piston damper with one with fewer or smaller holes will also help.

I must say the Rampage XT is a durable vehicle. I put it through some tough situations and the Rampage XT came out on top.

A word of caution for new RC drivers. The Rampage XT is fast and heavy. A truck of this size and weight carries much momentum. Hitting something, or someone, while traveling at even mid speeds will cause damage. While the Rampage may come out undamaged, whatever you hit will not. Please be careful running any RC vehicle, especially one of this size.

The Rampage XT delivers runs times of about 30 minutes. Depending on your driving style and tuning capabilities, you can have run times from 20-35 minutes.

VIDEO

The Rampage XT is definitely a ton of fun. It's powerful, fast, and BIG!

The Rampage XT handles well except for bottoming out on large jumps.

The engine runs great and only needed minor adjustments.

500cc gas tank offers 20-35 minute run times.

Heavy duty aluminum chassis coupled with thick plastic components offer a durable setup.

RedCat Racing
23 West Watkins Street
Phoenix, AZ 85003

Phone: 602-454-6445
Fax: 602-626-3543
Support Email: support@redcatracing.com
Sales Email: sales@redcatracing.com
Website: www.RedcatRacing.com

I'd like to give a special thanks to Wheelin in the Country for allowing me to use your facility to do my testing.

Wheelin in the Country
28 Anderson Creek Road
Summertown, TN 38483-7001

Phone: 931-964-3417
Website: www.wheelininthecountry.com