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Thunder Tiger Raptor 50S ARF Helicopter

Thunder Tiger Raptor 50S ARF Helicopter

A Proven Platform For Over 15 Years

How many types of Raptor 50s are available today? The Raptor 30/50 series has become one of the best selling glow-powered RC helicopters ever made. Because the Raptor is so stable and flies so well, it is still in high demand 15 years after the first Raptor 30 was introduced. Over the years, many minor improvements have been made and 2003 the Raptor 30’s tail boom was stretched to become the Raptor 50. The engine to main rotor gear ratio was reduced from 9.6 to 8.5 to better utilize the high torque from the 50-size engines. The Raptor 50 has an excellent power-to-weight ratio which makes it very agile, allowing even experienced 3D pilots to throw down maneuvers with this heli.

Author’s Opinion
The original Raptor 50 was introduced to the market ten years ago and over the years Thunder Tiger has steadily improved the design and released several different versions with the latest being reviewed here; the Raptor 50S. The Raptor 50S (sport) has unbeatable handling qualities because it is very predictable with no vices in flight. The classic 90-degree mechanical mix system provides very precise control with no undesirable cross coupling between the cyclic and collective controls.

Need To Know
TYPE: 50-size glow-powered ARF helicopter
FOR: Beginners to intermediate pilots
PRICE: $629.99

What We Used
RECEIVER: Futaba R617FS, FUTL7627
RECEIVER BATTERY: Hobbico HydriMax 4cell NiMH 2000mAh, HCAM6351

FLYING WEIGHT: 6.9 lb. (ready to fly)
LENGTH: 48 in. (1200mm)
HEIGHT: 15.7 in. (400mm)
WIDTH: 5.5 in. (140mm)
ROTOR SPAN: 53 in. (1345mm) with 600mm blades
ROTOR DISC AREA: 2206 sq. in.
ROTOR DISC LOADING: 7.2 oz./sq. ft.
TAIL ROTOR DIAMETER: 9.3 in. (237mm) with 100mm blades
ENGINE: Thunder Tiger Pro 50H engine (installed)
MUFFLER: Included
RECEIVER BATTERY: Hobbico HydriMax 4cell NiMH 2000mAh
RADIO: Flown with Futaba 10CHG and Futaba R617FS receiver
SERVOS: Ace S1807MG metal gear servos for collective, cyclic and throttle and an Ace 0606n high-speed digital for tail rotor (all installed)
GYRO: Thunder Tiger TG-7200 (installed)
GOVERNOR: Thunder Tiger Zero Alpha II (installed)
MAIN BLADES: 600mm wood blades (included)
MAIN ROTOR RPM IN IDLE-UP: 1,850 to 1,900
DURATION: 9 minutes
COMPONENTS NEEDED TO COMPLETE: 6+ channel radio system with heli programming, receiver battery, glow fuel and starting accessories

• Affordable price
• The mechanics comes assembled with engine, muffler, engine governor, gyro, and servos installed – Can be flight ready in approximately 5 hours.
• The new molded plastic links fit the 5mm steel balls perfectly
• A nearly indestructible molded canopy comes with the decals already installed
• Very clear instruction manual.
• Affordable replacement parts are easy to find at many hobby shops and online

• It would have been even better if the servo horns and pushrods were pre-installed at the factory
• All the pivoting mixing arms and bell cranks use bronze bushings instead of ball bearings
• Wood rotor blades

There are currently two Raptor 50s available: the Raptor 50 Titan SE (special edition) which comes only in kit form that includes a painted fiberglass canopy, a metal center rotor hub, and all the bellcranks are mounted on ball bearings. The Raptor 50S, which I am reviewing here, was just released in October 2012, is geared toward beginners and sport pilots who want a rugged, reliable and great value helicopter that requires minimal assembly to get airborne. The 50S comes almost completely assembled from the factory and it includes the engine, five servos, a gyro and an engine governor—all preinstalled. To keep the Raptor 50S affordable, Thunder Tiger chose to include wooden main rotor blades and a molded plastic main rotor hub. For beginners, it is very likely he/she will break the blades sooner or later and it is less costly to replace wood blades than carbon blades. As the pilot progresses, the wood blades can always be replaced by optional carbon rotor blades. For beginners and intermediates, the Raptor 50 is one of the best choices if you want a nitro-powered helicopter.

The Raptor 50S combo comes with a Thunder Tiger (TT) Pro 50H engine and a muffler already installed. This particular engine is a proven design and its 2-needle carburetor is easy to set. There is no rough running in mid-range and the idle will not die. I have had many TT Pro 50H engines over the last eight years and it is a reliable workhorse. The Pro 50H may not have the brute power of the newer TT Redline 53H and 56H or OS 55H engines, but the Pro 50H has more than enough power for 3D flying and it is user-friendly.

The Raptor 50 Titan SE uses ball bearings to support all the pivoting bellcranks and mixing arms. The Raptor 50S uses bronze bushings; hence there is a bit more free play in the controls. Beginners will not notice the differences during hover or normal forward flight. I recommend adjusting the tightness of each 3mm bolt that goes through the bronze bushings to get the minimal free play, then add oil at the bronze bushing to make the bellcranks pivot smoothly. Eventually, as the pilot becomes more proficient or feels a need to upgrade to ball bearings, a bearing upgrade is always available from Thunder Tiger.

Thunder Tiger Raptor 50S ARF Helicopter
The main rotor is what makes the Raptor 50 extremely docile and stable.

All modern Raptor 50 kits use the rugged tail rotor blade grips with larger bearings and the tail rotor hub from the Raptor 60/90. This makes the Raptor 50 tail rotor system very durable. The Raptor 50S comes with 100mm long tail rotor blades which extend the diameter to give the Raptor 50 phenomenal tail power. The brand new TG-7200 heading lock gyro and ACE 0606n high speed tail rotor servo included in the combo gives the 50S and incredible, locked-on tail control.

The Thunder Tiger toothed tail rotor drive belt is reinforced with fiber ropes inside. Even in the most violent pirouetting maneuver, the belt has never slipped. I prefer the belt over a torque tube because on a belt drive system no harm will be done if the tail blades brush the ground. With a torque tube system it is common for the tube to become damaged if the blades contact the ground or in a crash.

Thunder Tiger Raptor 50S ARF Helicopter

The Raptor 50S’s 8.5 to 1 gear ratio works very well. Most 50-size engines reach their peak performance at around 14,500 to 17,000 rpm. If we run the engine at 15,000 rpm at Idle-Up 1, then the main rotor will spin at 1,765 rpm, which is perfect for gentle aerobatics. If we run the engine at 17,000 rpm at Idle-Up 2, then the main rotor will spin at 2,000 rpm which allows the Raptor 50S to handle aggressive 3D maneuvers. A Raptor 50 likes to hover at 1500 rpm; this means the engine is only turning at 12,750 rpm. At this rpm the engine is working at a leisurely pace and the Raptor 50S is relatively quiet and can hover for 10 minutes on a single tank of fuel.

With all glow-powered RC helicopters, when an engine governor is not used, the engine rpm will tend to rev up during dives because the main rotor blade pitch angle is reduced to a flat pitch as the engine becomes unloaded. The Raptor 50S includes an engine governor to keep the engine running at a constant rpm no matter what the loading is. For aerobatic flying, I set the governor to 1,850 rpm in Idle-Up 1, and to 1950 for Idle-Up 2. The bottom of the Raptor’s plastic fan already has two recesses molded in to accept the magnets from the governor. The factory has pre-installed the Thunder Tiger Zero Alpha II engine governor and magnets on the Raptor 50S.

Thunder Tiger Raptor 50S ARF Helicopter
The Zero-Alpha II engine governor comes installed.

For beginners who are just learning how to hover, I suggest leaving the engine governor wire disconnected from the receiver and not use it. Beginners will often be hopping the helicopter near the ground or hovering just few inches off the ground and practicing a lot of taking offs and landings. When a beginner, gets into a panic mode, the best choice is to chop the throttle and let the helicopter gently settle back to ground. It is not desirable to have the main rotor and engine constantly spinning. Furthermore, beginners do not need the extra hassle and complexity of setting up an engine governor. Save the governor for future use after mastering hovering and forward flight.

For beginners, I recommend disabling the Idle-Up and Stunt Mode features and only use the Normal Throttle Mode for flying. Beginners can activate the Throttle Hold which is a good safety feature to prevent the engine from accidentally spooling up. If your transmitter has a 5-point throttle curve, then set up the values for the five points as 0-25-45-75-100. With the Raptor 50S, keep the middle point of the throttle curve at 40 to 45 which will produce hovering rpm of around 1,500, which helps make the helicopter very docile and pleasant to handle in hover.

I strongly recommend all beginners seek the assistance of an experienced pilot to check over any RC helicopter before the first flight. If they are willing, I would suggest that they perform the first flight as well. A seasoned pilot will know how to tune an engine’s carburetor in just minutes and he could also tell approximately what the rotor rpm is just by listening to the engine and rotor sound. He could easily tell whether the helicopter is in trim or not by hovering it. Additionally, he could then help adjust the transmitter control settings and the mechanical pushrods to make a helicopter much friendlier to beginners. A well-set up and trimmed helicopter makes a tremendous difference in the learning process. The tricks to make a helicopter fly properly come only from experience.

In The Air
The number one reason why so many people around the world love the Raptor 50 is that it has very predictable handling characteristics. The model does not bite you with surprises. The Raptor makes learning new maneuvers easier. Pilots will be motivated and feel confident to try new maneuvers. When I first flew my Raptor 50 for the very first time in 2003, it was love at first flight. I felt as if I had flown this model for a long time and performed what I wanted effortlessly. Like a good wine, the Raptor series gets better and better overtime.

Thunder Tiger Raptor 50S ARF Helicopter
The Raptor 50S comes with a new TG-7200 heading lock gyro.

The stock black color Hiller control paddles on the Raptor 50S have a perfect weight (30 grams). They make the helicopter very stable in hover and forward flight while still providing ample cyclic response for sport flying. As your skills progress you can add optional lighter weight (25 gram) white paddles or extremely light (20 gram) green paddles from Thunder Tiger. They will speed up the cyclic response rate significantly for aerobatic flights. All three color paddles have same airfoil shape, thickness, and paddle area, but use different density plastic. The black paddles make the Raptor 50S very stable but still allow you to fly loops, rolls, piro flips and more. Use green paddles for faster pace moves, like tic-tocs.

The stock wood blades are fine for learning or performing mild aerobatics because they are stiff and have lead weight epoxied in near the blades leading edge. Using 600mm carbon blades will make the Raptor 50S more aerobatic. Using optional carbon blades in conjunction with the lighter white or green paddles will really open up the flight envelope for experienced pilots.

The Raptor 50S does beautiful axial rolls. The large diameter main rotor disk propels the model at 60+ mph in forward flight and with a full right cyclic command, the Raptor 50S will easily complete two consecutive axial rolls in three seconds. The model does axial rolls to the left equally as well as to the right. With so much speed and momentum, the loops are very large. Average pilots can complete three consecutive round loops with little effort.

Thunder Tiger Raptor 50S ARF Helicopter

Pro Tips
• The difference between an ARF (almost-ready-to-fly) and a RTF (ready-to-fly) model is the RTF has been test flown and trimmed out at the factory. In general, it is more likely the screws on a RTF model have all been tightened. The Raptor 50S is an ARF model, which means the mechanics were assembled at the factory by someone probably who does not fly. I went through all the screws and bolts on my 50S before the first flight. It took me a total of five hours to add servo arms, fine tune the pushrod lengths (they were very close to perfect, but not quite), install my receiver, program my transmitter and thoroughly inspect the mechanics and fasteners.

• A 1.8 horsepower engine-powered model is not like a 450-class RTF mini electric helicopter. The Raptor 50S is a high-performance helicopter that requires respect. With any glow engine-powered helicopter, I strongly recommend to carefully wipe down and clean the model after each session of flight. As you clean the model you will discover little things that might need attention. Careful maintenance will prevent crashes. Engine-powered helicopters require slightly more maintenance because engines produce more vibration then electric motors and exhaust oil can get everywhere.

The Final Word
The Raptor 50S is the receiver-ready helicopter which comes assembled and with engine, muffler, five servos, gyro, and engine governor installed. The modeler only has to supply his own receiver and transmitter. At just over $600 for the entire Raptor 50S combo, it is a time and money saver. The best part is the Raptor 50S is based on a proven, strong mechanical platform and it features Raptor’s famous user-friendly handling qualities.

FUTABA, (800) 682-8948
HOBBICO, (800) 682-8948
THUNDER TIGER, (800) 682-8948

Words: James Wang Photos: Walter Sidas and James Wang