hirobo.co.uk

Anyone who is familiar with helicopters knows that Hirobo has produced the .30-size Shuttle and its many variants for years with great success. But Hirobo felt that it was time to update the Shuttle to today's design standards, so in 2000, the company released the Shuttle Sceadu. Among its many changes, the Shuttle Sceadu was made available as a .30- and a .50-size platform for the first time, and the .50 version was designed with 3D pilots in mind.

Now, two years later, the Shuttle Sceadu Evolution 50 offers demanding pilots even more refinements and performance. If you own a first-generation Sceadu, don't despair; many of the new Evolution 50's parts are interchangeable, so you can update your Sceadu at minimal cost.

SO, WHAT'S NEW?

To start with, the frames have been molded of a tougher material that adds strength and makes them more rigid. A new, third main-shaft bearing that's below the main gear further stiffens the frames and supports the main shaft better for precise gear mesh during hard aerobatics.

The redesigned fuel tank holds more fuel, and it's secured between the frames by four rubber feet that isolate it from vibration. Demanding aerobatics make the engine work harder and generate more heat; to keep the engine happy, the cooling fan has been improved to increase the airflow over the engine's head. This was a weak spot on the first version of the Sceadu.

The main rotor head is the FZ-IV, which features a machined-aluminum center block and has the flexibility to be configured to meet any pilot's proficiency level. For example, the Evolution's head features an "autostability" configuration that makes it a stable trainer. Moving a few control balls and changing their pick-up points make the heli a potent aerobatic performer. Some other highlights of the Evolution are push-pull linkages, two-piece flybar paddles with adjustable weights and a longer-than-normal tail boom, so you can use 600mm-long main blades.

KIT CONTENTS

The Sceadu is a true builders' kit; none of the assemblies are factory built. All parts are bagged according to assembly steps and are numbered to correspond with the manual. The manual is full of very useful information and contains more written instructions than Hirobo's past efforts have. This is a welcome change! The manual covers both the .30 and .50 versions of the Sceadu, so you must be careful to follow the appropriate instructions when they appear. The belt-driven tail rotor uses a new, thinner, more flexible belt for less resistance and incorporates a split-gear, constant tail-drive to turn the tail rotor during autorotations. The tailrotor servo is mounted on the tail boom for very positive tail-rotor control. All pivot points on the Evolution use ball bearings instead of bushings. The sleek canopy is blow-molded and very durable, and the decals are of a new high-visibility color and design. The kit also includes a muffler. One downside, though, is that the Evolution 50 doesn't come with any main rotor blades, as Hirobo assumes that very few pilots would use kit-supplied wood blades on a machine of this caliber.

ASSEMBLY NOTES

Before you start to assemble the Sceadu, read the manual and gather the tools that you'll need. You'll also need thread-lock (I used blue Loctite) for all metal-to-metal fasteners. The machining of the metal parts and the plastic moldings of the kit was outstanding; everything fit together very precisely!

Mainframe assembly. The frames are molded in halves that are screwed together. The servo tray, main shaft bearings, tailrotor pick-up and elevator lever are sand-wiched between the frames before they're mated. The one-piece servo tray has plenty of room for the radio components. Before you fully tighten the frame halves, slide the main shaft into the bearings to properly align them. Here's a tip: leave the landing gear assembly off the model until the engine has been installed. You'll need to spread the frames apart slightly to slide the engine and its mount into place.

Swashplate. The swashplate's composite construction is comprised of a plastic outer ring and a metal inner ring. You'll need to install the seven control balls in the rings. The longer balls are used on the inner ring, and I used a drop of thread-lock to make sure that they stayed put. Before I installed the outer balls, I used a 3mm cap-head bolt to thread the holes. Don't overtighten the balls, or you risk stripping the outer ring. I also placed a drop of thick CA on the threads before I screwed the control balls into place.

Main rotor head. The Evolution 50 comes with the FZ-IV rotor head and uses a conventional single axle design that's supported by twin rubber dampers. The blade grips are supported by two ball bearings and one thrust bearing. Before you build the head, you must choose which mixing options you're going to use. There are two positions for the Bell-Hiller mixing arms. The manual says the inside holes are for "high mobility," and the outer holes are for "autostability." Beginners will want to use the outer holes to make the model feel less twitchy and have greater stability in the air. Be certain to grease the thrust bearings and install them correctly; the race with the larger inside hole is inserted first. The flybar paddles have weights that you can remove to fine-tune the model's control response. I recommend that you leave all of the weight intact. The rotor system has great control authority, and if you remove any of the paddle weight, the heli becomes very responsive. I was slightly surprised that the flybar is only 3mm in diameter because it might flex under high-load maneuvers. Given the acrobatic potential of the heli, I thought the flybar should have been beefed up to a 4mm diameter.

Tail rotor/tail boom. The tail rotor is easy to assemble, and each blade grips a ball bearing and a thrust bearing. Just as you did for the main rotor, grease the thrust bearings and install them correctly. Before snapping the case halves together, make sure that you capture the drive belt. I balanced the tail rotor on a High-Point balancer before I installed it on the output shaft. This is a must for vibration-free operation! I installed the tail-rotor pushrod guides and the tail-rotor servo mount on the tail boom before I mounted it on the main frame assembly. Make certain the drive belt is twisted in the proper direction; if it isn't, the tail rotor will spin backward.

Engine assembly. Over the past several years, heli manufacturers have made engine installation much simpler, and installing the Evolution's engine is no exception. The cooling fan threads onto the engine's crankshaft, so it should run very true. Be sure to leave the engine-supplied spacer on the crankshaft for proper spacing. There are several ways to tighten the fan onto the crankshaft; some are good, and some are not so good. The recommended method is to remove the engine's backplate and jam the crank with a wooden dowel. Never use a piston-locking tool that screws in from the glow-plug hole; you risk denting the top of the piston, or worse, punching a hole in it. After I had installed the fan, I checked its runout with a dial indicator, and it was almost perfect. I fitted the clutch and starter shaft and checked their runout. I then fit the clutch-bell housing and slid the engine assembly into the main frames. Lining it up and setting the gear mesh went without a hitch.

Radio installation and setup. I installed the servos, the receiver, its battery and gyro as instructed by the manual. I then screwed the control balls onto the servo wheels and made the various pushrods. Take your time here, as the pairs of pushrods must be exactly the same length. The manual very clearly specifies the correct location of each pushrod and the direction in which each servo moves. Following the manual, I set up the 5-point collective pitch and throttle curves quite easily.

Final touches. All that was left to do was trim the canopy, apply the decals and mount the tail fins. I'm really glad to see that the Evolution's decals are multicolored for better visibility and orientation when the heli is in flight. The canopy uses vibration-absorbing, rubber grommets that slide over posts mounted on the frames; the canopy hardly shakes at all when the engine is running.

FINAL THOUGHTS

The Hirobo Sceadu Evolution 50 has evolved into a real class act; it's easy to build, and the rotor head provides excellent stability and control response. The model features bearings on all pivots points, constant tail drive, a push-pull control system, a decent muffler and very good instructions. It's nice to see a manufacturer such as Hirobo listen to modelers and incorporate their suggestions to improve a model. It's this type of attentiveness that makes Hirobo a leading manufacturer of RC helicopters!

High Point; distributed by Robart Mfg. (630) 584-7616; robart.com.

Hirobo; distributed by MRC.

JR; distributed by Horizon Hobby (800) 338-4639; horizonhobby.com.

Loctite (216) 475-3600.

Morgan Fuel (800) 633-7556; (334) 347-3525; morganfuel.com.

MRC (732) 225-2100; modelrectifier.com.

O.S.Engines; distributed by Great Planes Model Distributors (217) 398-6300; (800) 682-8948; osengines.com.

hirobo.co.uk

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