The Kyosho Caliber 5 box. It has a cute carry handle on the top!

Contents of the box.

Sample pages from the manual.

Engine and included Kyosho muffler installed.

Bellcrank with bearings and collar.

Push-pull pitch for mechanical mixing system.

Metal head block, 6mm spindle and hard dampening.

Pushrods attached and boom on.

Due to the diverging rods, the holes in the servo wheels are not meant to form a straight line with the centre. Note the GY601 controller and battery on the top shelf and the reciver on the bottom within the strong box.

Big header tank with mounts clipped to the frames.

Tail pushrod changed to a ball link.

The Caliber 5 comes in ARF form, with a surprising amount of the assembly already done for you. In the box, the main frames, head and undercarriage are already assembled. The canopy is fitted over the frames. Seperately within the box is the tail boom, with belt, fins and tail gearbox already attached. The boom supports, blades, stickers, manual and box of other bits is also in here.

My Caliber 5 also came with a washout base in a seperate bag, with a note saying to replace the one on the model with this one. I could not see a difference, however I did the right thing and replaced it.

The manual is clear, well illustrated and lengthy as it goes into full detail and only tries to complete one step at a time. There is a note near the front explaining which steps apply if you have an ARF kit with or without engine.

As with all models, it is wise to disassemble everything to check it over, as it can save a costly and embarassing rebuild.

In my case, I started at step 30 of the manual which is about installing the motor. This was quite painless. There is a flywheel and clutch put onto the crankshaft, then a hub which threads onto the crankshaft. I used an OS crank-lock tool and some loctite to make sure it was not going to undo when starting. The fan is then attached to this hub with two M3 bolts. The engine mount assembly is quite solid and aligned well in the frames.

I attached the supplied muffler with 24 hour epoxy to seal it.

Next was the tail boom. This is thin, probably a side effect of the advances in belts which have allowed for a thin belt. The tail is light and strong, so I don't have any problems with it being thin. Next came the pitch servo and bellcrank. It is reassuring that there are bearings in all the levers.

Next were the pushrods. This is where you get to see how the mixing actually works. The mechanical mixing is a beautiful system. Like with the Robbe System 88, the cyclic servos go straight through a bellcrank and to the swashplate. Both cylic servos are moved in a rocker arrangement by the pitch servo, which is push-pull. The cyclic is also push-pull, with intersting diverging pushrods which require some care when drilling the holes in the servo wheels due to them not being in an exactly straight line with the servo centre, but instead forming right angles with the (diverging) pushrods. As I had not powered up the servos yet, I left the final attachment of the servo wheels until I knew where the centre of servo travel was.

If you're using Futaba servos, the big wheel that comes with 9252s needs to be cut down a bit, however the smaller wheels such as those that come with 3001s fit nicely.

The model includes a crash-box to store your receiver and battery in. This is a good idea. The box is part of a frame sub-assembly and so if you break it, you can replace it without changing the frames also.

I had to be careful laying out the gear to go in the radio box, as I was using a Futaba 601 Gyro and the controller was perhaps more than Kyosho had intended to go in there. In the end it all worked out ok, with the standard Futaba 1600mAh battery being used.

The inbuilt header tank is also something unusual. It is held in place by two clips that attach between the tank and the side frames, which reduces the chances of you having to replace side frames in a crash.

The canopy mounts are attached to the side frames with two self tapping screws, again, reducing your chances of having to replace side frames after a crash. The whole canopy mounting system is novel, with push in locks to hold the canopy in place. If this system manages to not wear over time, I think it will be a clear winner.

The main shaft is 10mm and solid, not hollow. The feathering spindle is 6mm so it should stand up to some beating without getting out of shape.

The head dampening is the hardest I have seen on a 50 size model taken out of the box. Kyosho do appear to have considered the 3D market with the cal5. There are standard looking 50 size rubber doughnuts, with plastic sleeves between them and the 6mm feathering spindle.

A metal head is also there, which is something that will hopefully prove it's worth after many hours of flying when it is still solid and not sloppy.

The bell/hiller mixing arms are designed to be at an angle at zero degrees of pitch, like on the bigger and incredibly more expensive Caliber 90. The pushrod from the swashplate to the arm joins the arm at a right angle, so the arm is not horizontal, but that's ok.

The drive system involves a pulley mounted above the fan, which drives a big thick belt that goes around and past the main shaft to the autorotation bearing and shaft at the back. This drives the tail and through another gear, the main blades. It's pretty much the same as the Caliber 90 again, so there isn't any question of wearing out or handling the power as far as I am concerned.

Unlike the Caliber 90, the fan is directly attached to the crankshaft. This obviously reduces the parts count and weight but also removes a point of failure when compared to the Caliber 90.

The muffler is also unusual. We are pretty certain it is a tuned system as the engine loves to hang onto its revs once it gets going properly. The power is good, although it is louder than expect on an otherwise quiter than usual helicopter.

The tail pushrod uses a z-bend to attach to the servo. We don't know why Kyosho have chosen to do this, it's certainly not in fashion today, the theory being that the servo horn will wear and introduce signifcant slop into the system. I changed mine to a normal ball and link.

The bearings are not mounted in bearing blocks, as on a raptor. I think this makes your bearings last a lot longer compared to models with metal bearing blocks which seem to need new bearings after the most minor of crashes.

The model as a whole is light.

Finally, and quite importantly, the canopy isn't too bad, especially compared to many of the disgraceful creations to have come out lately.

FLYING
The first thing I noticed is how quiet the model is when started. It does get louder once it is up to speed though.

The model hovered nicely, so it was time to do some circuts. It was here that engine tuning was performed and the effects of the muffler showed themselves. If the engine is too rich, it will never get to the right revs to get the muffler working for you. After a few tweaks the note changed a lot and the head speed leapt up.

The stock paddles showed themselves to be a little tame, as with most kits, so I changed to some v-paddles. Now the roll rate was more to my liking.

Doing some loops showed how powerful the OS50 Hyper and muffler combination was, producing quite big loops.

Next some tick-tocks were flown, with the model managing to not add any extra inputs to the mix, which was good of it.

The one piece undercarriage is a novelty. After giving this model about as hard a days flying as is possible - and you would be surprised what a model can take - the undercarriage provided many very hard landings without breaking.

My Cal5 has been through a lot, including learning low flips out of inverted autorotations and entering into a novely 'smackdown' event autoing onto a small table. It has had minor damange done to it a few times, always being less than the assembled crowd that came to see the beating and I expected. The blade grips seem to be the first thing to break, breaking where the ball joint screws in. The other components are the usual suspects in the boom, blades and feathering spindle bending. I am yet to break the one piece undercarriage.

The included blades are more than servicable carbon blades. They auto quite well and roll fast also.

I also tried moving the pitch link on the bell/hiller mixing arm to the outward position. I believe this increases the bell (swash) input without changing the hiller (flybar) input, effectively decreasing the flybar ratio. I was getting pretty impressive cyclic now!

The tail control is more than comparable with other 50 size helicopters with the same gyro. It's no 90 size model with a torque tube, but it's surprisingly good. I put a GY601 in mine as I'm not interested in mucking about with the tail.

I found that I could get more travel (ATV) on the aileron servo than the elevator, due to it being closer to the bellcranks so its pushrods were on a greater angle. Trust me. It's the go.

I have still not fitted a glow extension to the model as I am unaware of any manufacturer that makes one that doesn't break after a few weeks of flying.

CONCLUSION
So is it good? Kyosho have managed to make a 50 size heli that takes on the rest. There is nothing wrong with the mechanics, it's light, has the right strength bits where needed and includes an elegant mixing system. They've got the price right and it includes things like carbon blades and a driven tail. If the parts prices right also, they'll be on a winner.

Doing some 3D

Using V-paddles to get the cyclic for low sideways tic-tocs, I have since changed back to the original paddles with more swash deflection.

Good looking compared to many recent canopies.

It looks like a 50 and flies like a good 50.

With the tail well set up, it holds nicely.