Hirobo Shuttle Plus

Model Airplane News, Feb 2003 by Bell, Phyllis

A new spin on an old favorite

For more than 15 years, the Hirobo Shuttle helicopter series has been flown and loved by pilots all over the world, and Hirobo continues to improve the breed with its new Shuttle Plus, What sets the Shuttle Plus apart from other Shuttles? By doing a little research, I learned that Hirobo has made several changes that improve the quality, durability and safety of an already great heli. And to add to the value, Hirobo has dropped the price of the Shuttle Plus; it's one of the least expensive .30-size collective-pitch helicopters on the market today.

A number of features have been upgraded in this new Shuttle. For starters, the blade grips have adjustable linkage geometry to suit both beginners and experts; you can now tune the control response to match your flying skills. A new heavy-duty clutch will ensure many trouble-free hours of operation, and the tail-boom supports are almost the same size as those on larger .60 helis. With the improved performance that we've seen in hells over the past few years, one change I'm really glad to see is that the blade bolts have been increased in diameter from 3mm to 4mm. There's no chance of losing a blade with these larger, stronger bolts. Other changes include a larger muffler that allows the engine to breathe more easily, RG-style tail fins and an SE-type tail-pitch lever for solid tail-rotor control. A big surprise, though, was the included Sceadu high-performance fan and flywheel assembly. This unit does away with the tapered-- collet system that centered the fan on the engine. It instead threads onto the engine's crankshaft and eliminates a very tedious task. These changes make a more precisely engineered machine. Let's put it to the test!

WHAT'S IN THE KIT?

When I opened the box and pulled out the instruction manual, I was happy to see that all of the subassemblies had been packaged separately and numbered to correspond to each step in the manual. This really helps to speed up the construction. During my exploration of the kit's contents, I discovered an upgraded swashplate. This wasn't mentioned in any of the literature included with the kit, so be sure to look for it.

ASSEMBLY NOTES

This review is not intended to provide a blow-by-blow description of each assembly step; instead, I'll cover the areas that need special attention or are not covered in detail in the manual.

Construction starts with the elevator and aileron levers and quickly moves to the main frames. Though the frames may look familiar, they are cast from a new type of resin that increases their strength and durability. One thing is for sure; the screws thread much more tightly into the frames-- so tightly that my wrists were soon sore! Before you mate the frames, make sure that you capture the elevator lever between them; if you don't, you'll have to separate the frames and start again. When I installed the bearings that support the main shaft, I used the shaft to align them properly. The collective-pitch lever, fuel tank and servo mount are also added to the frame. These subassemblies went together easily in less than 30 minutes. Next was the installation of the main gear. Here, I took extra care to make sure that the main shaft was seated before I secured the mast lock. There shouldn't be any vertical play in the shaft.

MAIN-ROTOR ASSEMBLY

The rotor head is the tried-and-true FZ unit that performs very well. It can be built quickly and easily. Pay careful attention when you screw the balls onto the blade grips; they can be screwed into two possible positions. This is one of the changes that Hirobo made to adjust the control response. The manual recommends the use of the inner hole, and if you're a beginner, this is the one to use.

I paid special attention when I built the flybar assembly, as it must be centered in the rotor head, and the paddles have to be parallel with each other. I also balanced the rotor head, even though the manual says nothing about doing this. I used a Robart High-Point balancer to balance all of the heli's rotating parts. The plastic swashplate is included in the parts bag for step 13; please discard it and use the upgraded swashplate.

One part that gave me a little trouble was the radius block (or swashplate driver). When it's secured on the main shaft and tightened, it shouldn't be able to move. (If it moves, the control inputs will not be properly timed.) No matter how hard I tried, I couldn't get it to damp tightly on the shaft, so I replaced it with a metal unit. You can simply use a file to open up the gap between the ears in the block. When you tighten the screw, it pulls the ears together so the block clamps more tightly on the shaft.

TAIL-ROTOR ASSEMBLY

I thought the tail rotor looked a bit intimidating to assemble, but it was actually pretty simple; it went together precisely. Just be careful not to overtighten the bolt that holds the guide pulley; if you do, it will bind and quickly wear out. Also, make sure that you install the drive belt before you screw the gear-case halves together. Again, I balanced the tail-rotor assembly before I installed it on the output shaft.