Assembled frame ready for some Shuttle parts
Background
On May, 1998, K&S debuted a conversion kit for Hirobo Shuttle in a hobby fair in Japan. The kit (K&S # 671) featured carbon fiber frames and ECCPM controls, and listed for 37,500 yen (About US$350-). The K&S kit is a main frame conversion that cannibalize the rotor head, gear train, and tail assembly from a Shuttle.
"Regular" helicopters use mechanical levers to perform the mixing of cyclic and pitch control, and ECCPM did away with the mixing levers and use direct connection from the servo to the swashplate, and all the mixing of controls is done by the transmitter software. Even though most people refer to the electronic mixing of cyclic and pitch control as simply CCPM, but I like to refer it as ECCPM cause CCPM is just a regular term that described the mixing of various commands to the swashplate, and it can be both mechanical and electronic. The use of the term CCPM to describe the electronic mixing of cyclic and pitch control is not correct. ECCPM was first used in some European helicopters for some time, but due to the demand of complicate mixing arithmetic that is required on the computer software of the transmitter, it remained to be a novelty. About three years ago, JR actively pushes the 120 degree three point CCPM control mechanism, and revamped their transmitter software to make it more user friendly. With JR's effort, now ECCPM helicopters is like a heat wave that swept Japan, and most r/c helicopter manufacturers is producing and designing new models that uses ECCPM for controls. The main advantages of ECCPM is less parts count, and it translates to less slop, less cost of production, less weight, and less maintenance. All these lesses means a lot more to us r/c flyers.
Coming back to the K&S kit. The whole kit comes in a small box, and all parts are packed in plastic bags. The kit is a stack frame design, and the frame is made of graphite. To complete the kit, I have to buy a 3 point 120 degree CCPM swashplate. Both JR and K&S have swashplate of this kind. The K&S swashplate is designed to be mounted on a lot of other different helicopters, so I got a top of the line K&S type RS swashplate.
On the box of the kit, it said "For expert modelers only". When I saw that statement I sensed disaster coming, and I am right. Instruction was one page Japanese text with some black and white photos, and no drawings. All photos are not clear, and there is no exposed drawings as to what goes to where, and how the pushrod and radio have to be set up. I guess all these information must be hiding inside those Japanese text. Without any knowledge of the Japanese language, I am on my own. The manual was better than none, I guess. I started reading those pictures in the instructions real carefully, and try to decipher the numbers and the Kanji characters that is similar in meaning to Chinese characters, which I know. Then, after reading it several times, I took a deep breath, and started cutting the bag.
The first photo told me to sand and seal the edge of the frames. The frames are 2mm graphite plates, and the edge is free of loose graphite fibers. I went ahead anyway and smoothed the edge with 400 grit sandpaper, and sealed them with CA. The second one showed that I have to fit a pair of bearings to one of the opening of the upper mainframes. Luckily there are only a pair of loose bearings, so I gathered the bearings and tried to press in the designated opening, then I realized that the opening was too small. I used a reamer to carefully ream the hole bigger to give the bearing a snug fit, and secure it with CA. The next picture showed a completed frame, so I gathered the three bearing blocks and all the cross members, and dry fit the whole frame. Once again I use stainless steel countersunk screws with countersunk spacers to secure main frames together like all of my other helicopters. I guestimated what goes to where, and constructed the whole frame. Even though the picture did not show a fuel tank being mounted, I went ahead and mounted the fuel tank when I assembled the frame. However, I found that after fitting the stock Shuttle fuel tank there is still a lot more space available in the fuel tank opening. Did I did anything wrong, I asked myself. I read the pictures of the instructions and the fuel tanks were snug fit, hmm. Finally, in the text besides the picture that showed a close up of the fuel tank, I saw a clue – JR60333. Ah that is the part number for the JR Ergo Type II fuel tank. I got the Ergo fuel tank and fit it into the frames, only to find out that it is a snug fit. A big fuel tank, this is great!
During assembly of the frame, I realized that the cross members that comes with the kit was not a regular cylinder as with other helicopters, but like an “I” shape with the faces that touches on the frames in a larger diameter. These cross members gave more stronger mounting then regular cross members, and if they have a little hole in the middle like the ones with TSK then they are perfect. After I dry fitted the frame, I put it on a piece of mirror, aligned the frames, and secured each bolt once again with Loctite.
Next on the list were the installation of bellcranks. This was not clearly shown in the instruction as it only showed a close up look of the bellcranks. I gathered all bellcrank and related parts and guesstimated once again. This time was more painful and it took me two times the time of assembling the main frame to get those bellbranks right.
Final mystery of main frame is the gyro mount. There was no photos to show the mounting of the gyro mount, and it was already there in every photo of the assembled frame. At first, I thought it was a piece of aluminum part that comes with the kit. However, there was none. I asked my supplier and he said that I should use the gyro frame from the Shuttle. I then use a Correct aluminum gyro mount to fit into the frame.
After all these guesstimation, a frame is finally sitting in front of me ready to take up some Shuttle parts.
|
|
Assembled frame ready for some Shuttle parts |
I fitted the new swashplate, together with mixing arms and rotor in place. Seesaw, mixing arms and slider are Hirobo G-parts. The main rotor is an aluminum one from Pioneer. The mechanics of the Pioneer main rotor is the same as the regular Shuttle, but is lighter, have a top stopping disc, and have 4mm blade bolt holes. I also use graphite flybar stiffeners to beef up the flybar, and Hirobo G-parts paddles as seen in GPH 346 and Shuttle RG.
 |
|
Pioneer rotor head |
From my last trip to Japan, I got a kit from Pioneer that lets a Shuttle to use an OS46FXH as its power plant, so I incorporated it into the K&S frame. The spaces for engine is so big that the headroom can fit a 60 engine and still left some spaces for glow plug wrenches to go in. I had to grind an opening on the left side of the lower main frame to clear the muffler. Unlike the original Shuttle, this K&S kit enables the setting of gear mesh.
 |
 |
|
Close up of the OS46FX-H installed into the frame |
Close up of the drive train |
I used the tail belt assembly of the GPH 346, and that enables me to use 600mm main blades. Tail gear box and rotor assembly are Hirobo G-parts, with Capital tail pitch plate, ARK pitch slider and Pioneer tail gear. One thing that I like for he ARK pitch slider is that it can be controlled by a single pin that was mounted into the slider, or through a C-clamp style pitch plate of the Hirobo G-parts. The Hirobo G-parts tail rotor assembly featured dual ball bearings on each blade grip for smoother pitch change.
 |
|
Tail gearbox |
Final bits and pieces involved grinding a slot on the upper side of the canopy to clear one of the control arms. One thing I like about the Shuttle was its canopy mounting that made taking out of the canopy a breeze. The kit enabled the use of the original Shuttle plastic canopy and its secure latch to make canopy mounting very clean.
Radio installation is another guess-timation marathon. I use PCM10X with JR4000s on all three control points of the swashplate and 2700G on tail. The gyro was an Arcamax Pi with 2700G mode. The servos are secured with self tapping screws into ABS grommets, and most of the servo spaces are tight. The manual did not mention or showed how the orientation of the servos, or how they are being mounted, so I have to test fit each of the servos before securing them. Next thing to guess were the pushrods from servos to bellcranks, and the size of servo discs to be used. I used my experience and set up the pushrods to make every of them perpendicular to the bellcranks. Radio setup is another guessing and I tuned various reverse switches to make the swashplate tilted to the controlled direction, and tried setting ATVs to limit the degree of control on the swashplate to eliminate binding on extreme positions. After setting up the servos, I went ahead to set up the rotor linkages and then the pitch, only to found out that my setup gives a whopping 30 degree of pitch window!
Flying
Flying the K&S CCPM Shuttle would make you forget all the hardships in assembly! It is a true sporty machine. Aerobatics were executed with precision and crude power of cyclic. The flight speed of the K&S CCPM Shuttle was fast due to the fact that its much lighter than the original Shuttle with the plastic frames. Comparing with the Shuttle RGM, the K&S CCPM conversion was more suitable for 3D. In the past, I've tried using a 46 engine in a plastic Shuttle, and found that no matter how I adjust it the plastic frame just could not resist to shake due to the increased torque of a 46 engine. While the carbon frame of the K&S CCPM conversion could take the 46 engine with ease, controls became on the sensitive side, and this setup should only be used by experienced pilots to avoid any mishap because flight speed was simply outrageous.
Conclusion
The K&S CCPM conversion kit would give your old Shuttle new life. However, its availability and its price would make it out of reach to most.