Two years after the release of the Sceadu, Hirobo introduced the Sceadu Evolution, which is an update version the already successful selling Sceadu. The Sceadu Evolution features the following new designs that is updated from the original Sceadu design:
All the above transcend the Sceadu into a more refined and precise helicopter. According to Hirobo, over 40% of the Evolution 50 parts are newly designed parts compared to the original Sceadu 50.
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| New mainframe | New servo frame (Note 2003 imprint) |
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| 480cc "Big" fuel tank | FZ-IV rotor head |
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| Push-pull collective controls | Plastic 3rd bearing block |
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| New DTDS split main gear | New 600mm symmetrical FRP main blades |
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| New 2 chambers muffler | New design decals |
Here are the dimension of the Sceadu Evolution as follows:
Engine size: 32-50
Rotor diameter: 1,248-1,348mm (550mm-600mm blades)
Tail rotor diameter (With stock tail blades): 244mm
Gear ratio (engine:main:tail) : 32 - 9.66:1:4.65, 50 - 8.7:1:4.71
There are 8 different packages of the Sceadu Evolution. There are the HPM (Mechanical mix) versions that either comes with engine or not, semi-assembled or kit and the others that are SWM (ECCPM). Aside from the blade length and engine mounting, the difference between a Sceadu Evolution 50 and a 30 is that the 30 kit have the single point collective control and the one-piece dual main gears as with the original Sceadu.
This article is to review a Sceadu Evolution 50 kit. In Hirobo's sales literature, it touted the Sceadu Evolution is a kit where upgrade parts are not needed in order to perform, so in this review I would try to use less upgrade parts to assemble the Evolution, test it to see whether Hirobo's claim is good. Let's take a look at the assembly of the Sceadu Evolution.
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| The first view after open the box | All parts neatly packed in bags |
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| Box content | ¡@ |
The packaging of the Evolution kit is like the original Sceadu, with All parts packed nicely into different bags and according to the steps of instructions. All bags are packaged in a way that when I arrived to a step of instruction I open one bag that is tagged with the step number in relation to the instruction and all the parts and screws required for that step of assembly would be included inside that bag. The instruction manual of the Evolution is by far the best Hirobo has to offer, not only does it have the usual highly detailed drawings on assembly, but it has a lot of in depth tips on how to setup, flying and maintaining the helicopter kit for beginners. In addition, gone are the "Jap-ish" that is usually seen in other Japanese made helicopter manuals, and I know Jeff Green of Altech has his contribution on the English part of the description to make it more pleasant reading for English reading owners.
The first part of the assembly dealt with the main frame, that also houses the elevator arms, the fuel tank and the front radio tray. The main frame is one of the major piece of update for the Evolution. First inspection found that the whole main frame, although not much different from the original Sceadu, but the pieces are much harder to be bent compared with the original Sceadu. Later, I confirm with Hirobo that most plastic part of the Evolution are being molded by a blend of plastic and graphite. This type of "graphite-plastic" has been used widely by r/c cars to firm up their chassis, and now they are being used in the Evolution. Hirobo told me that their R&D department tried different compositions of plastic and graphite blends, and finally comes up with the 22% graphite/78% ABS blend that is being used in the Evolution, and according to Hirobo too much graphite mix would make the plastic hard but brittle, and this blend is used after a lot of trial and errors. The elevator arms assembly was straight forward, though special attention must be paid to the orientation of the elevator arms, cause if you got them wrong you may have to disassemble the frames again. The fuel tank is the 480cc one that is optional for the original Sceadu, it comes with all fuel lines pre-cut for suitable length and four big grommets are used to hold it onto the main frame. I've used this optional big tank with my Sceadu 50 and found flight time of 10 minutes is possible, and glad to see this fuel tank as standard equipment in the Evolution.
The front servo tray has a lower portion that had a tub to house the receiver Ni-Cd pack, just like the original Sceadu. At first, I thought the servo tray is the same part of the original Sceadu, but I noticed that the mark on the tray says "2003", which should be a new molding? I did not notice any difference on the servo tray of the Evolution compared to the original Sceadu, except that the plastic is more stronger. In fact, all though the construction a lot of plastic part first seems familiar, but careful inspection reveals that its different design. Foam wrapping was supplied to prevent the pack rubbing inside the tub. The tub was big enough for a 2,000mah Ni-Cd pack. After assembling the elevator arms, fuel tank and front radio tray, all these are supposed to be sandwiched by two plastic main frame halves at this moment according to the instructions manual, but I left it out until later stage when I finished assembling the main frame with drive train to ensure proper alignment. Stock Evolution included metal philips screws and hex nuts to secure the parts, and I changed them to stainless steel hex screws and lock nuts for more strength. Before aligning the drive train, I just tight the main frame screws lightly at this point to hold the parts together, and wait until the installation of the drive train to align and finally tight the screws. This measure does not mean that the main frame pieces of the Evolution are not correct and precise, in fact all pieces comes together fitting each other well. The main bearings goes into the plastic frames, while the fitting of the bearings to the frames were tight fit, I applied some Loctite on the side of the bearings to prevent them from turning loose inside the frame. The plastic third bearing block is to be fitted onto the main frame at this step. With the original Sceadu, I already feel the third bearing block is a "mush have" cause it greatly strengthen the structure of the whole main frame, and the inclusion of the third bearing block in the standard Evolution kit is good. The fuel tank was housed in between the lower main frames, and was hold onto position with four rubber grommets.
The tail pinion assembly of the Evolution is in fact the same thing as the original Sceadu, where the whole assembly comes fully assembled from the factory. I found that the Evolution could use a plastic Shuttle lower tail bearing block (Hirobo part #0402-523) on the top of the belt drive gear to strengthen the support of the whole front tail drive mechanism. Now, the front tail drive mechanism was being supported with three bearing blocks, instead of just two. The extra bearing block not only reinforces the whole tail drive, but also act as a cover to prevent the belt from jumping out of the tail belt gear if belt tension came lose during flight. According to the instructions, fitting the landing gear comes next, but I intentionally skip that and wait until all the mechanics have been fitted onto the main frame.
Finishing up the main frame was to put on the canopy mounting posts. For a detailed description on how I assembled a plastic main frame, please refer to my page about "Tips on assembling a helicopter ".
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| Elevator assembly & fuel tank | Front radio tray |
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| Assembled main frame | ¡@ |
Next was the fitting of the drive train. The main shaft of the Evolution was 10mm diameter, in fact the same one as the original Sceadu. It provides two mounting length adjustments (178mm and 182mm respectively) and the instruction said to use the 182mm hole, not the 178mm one as used by the original Sceadu. The longer length main shaft setting should provide better hovering characteristics. Of interest were tiny groves on one end of the main shaft to designate directions and for better gripping of the washout guide. The DTDS gear is another new major part of the Evolution 50, where this time "real" split gears comes standard on the package compared to the molded one piece dual main gear as with the original Sceadu. I checked the dual main gears and feel that although these gears are molded plastic, not machined Delrin as I would have wanted, the stock main gears are correct in gear mesh, without any wobble and when taken care of they would provide very good service. I replaced the stock collar with a "clamp on" style one from Correct to prevent denting on the main shaft.
Once again I skipped steps to fitting the engine onto the main frame because I wanted the whole drive train to be fitted and align. Like the original Sceadu, the Evolution 30 and 50 each have different engine mounting part for their engine, and basically the helicopter size of the two are the same. As to production Evolution 50, for kits include engine, a special OS 50 SXH with OS60D (two needles) carburetor is included. (Note: Mine is a pre-production model and includes a OS60B 3 needle carburetor. This configuration is for prototype purposes and is NOT the final version on sale in the market) This engine is co-developed between Hirobo and OS, and includes the OS 60D two needles carburetor originally for OS 60 size engine. The clutch hub included in the kit is the type that uses collets as with the original Sceadu, but I changed it to the optional Hirobo 0412-191 SD flywheel for OS50. This optional clutch hub uses the woodruff key that comes with the OS50 instead of the fan collets, and I feel this clutch hub would give much better precision than the collet type hub as there is absolutely no need to dial indicate the clutch hub, and I liked the blue anodize on the optional hub too. The clutch, which is a hefty one, sat on top of the clutch hub. A fixed shaft on the clutch links to the start adapter, which is a 7mm hex type, and due to this design the owner had to have a starter with one-way bearing installed. The clutch bell sits on top the clutch, with part of the pinion inserted onto a bearing inside the main frame. I used some loctite on the clutch bell pinion to fix it in position with the bearing. After securing the engine onto the main frame, I checked the alignment of all drive train parts once again, secure all screws that holds the main frame, and install the servo frame. On the underside of the main frame, I installed two Hirobo 2511-024 M3X60 cross members to further strengthen the main frame and act as fuel tank support. These cross members are installed at the lower main frame where holes are already drilled on the frames. With the original Sceadu, all it takes is one hard landing to drop the fuel tank out of the main frame, and with these cross members the fuel tank would not drop as easily. In one of the cross members that goes under the fuel tank I slipped two pieces of fuel tubes to support the fuel tank.
The Evolution kits comes with a muffler in their box. This muffler is again another new part, where a baffle is now included for more silence operation. However, I find the stock muffler be too restrictive, so I choose a K&S HN-50 muffler instead. I connected a K&S header tank and all fuel lines were being connected to the engine. The Evolution's main frame have a very nice fuel shut off valve built in like the original Sceadu, and this time the opening is more narrow to ensure complete pinch of the fuel line when used. Fuel cutoff and release was just by sliding the fuel line up and down the "tear drop" hole. However, I checked the inside of the "tear drop" hole and find that it has rough edges that might cut into the fuel line, so I used a file to smooth out the sides of the "tear drop" hole.
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| New DTDS split main gear | Closeup of drive train |
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| Engine assembly | Special OS 50 SX-H engine with 60 B carburetor |
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| Optional blue fan hub | Whole main frame with drive train installed |
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| M3X60 cross members installed | Fuel tubes used on cross members |
The FZ-IV is a major new component of the Evolution, in fact a completely new design. Compared to the FZ-III rotor head, which is just an upgrade of designs from old Shuttle rotor head, the FZ-IV is completely design from the ground up as a new part without any reference to old Hirobo rotor head designs. The FZ-IV design have very high bell-hiller mixing ratio, under slung flybar, and have blade grips flipped to the front. Basically, this design should result with a very high aerobatics capability. Each blade grip is supported with two bearings and one thrust bearing, with all mixing arms and rotation points bearings equipped to ensure smooth operation. The flybar control bracket consists of a very long seesaw part, with a long flybar control cage and two mixing arms on each side, similar to the design of Hirobo's top of the line SSR-VI rotor head as used in their Freya WC. All plastic parts of the rotor head are once again being molded in the graphite-plastic so the whole structure is very firm. While assembling the rotor head, care must be taken on the alignment of the flybar control cage, as if it is not aligned properly the cage would become warp and thus would not function properly. There are two settings available for sensitivity of rotor head control to suit different needs, and I used the "High stability" setting. The flybar paddles are the ones from RGM and GPH, that weight of the paddles could be adjusted by taking weights out of the paddles. After assembly, I put the rotor head on a high point to balance. As to the mixers and the swash plate, they are in fact the same items as with the Freya. Care has to be taken while setting up the timing of the washout slider. The slider and the fixer are designed to be slant at an angle, and if you aligned the washout arm not perpendicular to the rotor head, phasing would produce and there would not be positive control on the cyclic. (e.g. aileron would be introduced when just elevator commands are made, and vice versa). All during the assembly of the rotor head and the sliders, on the part where screws were being screwed into a plastic part, I would always use a tapper to prep the hole first, then use CA glue to fix the screws for more strength.
Various mixers and the pitch control arms are now being fitted onto the main frame. The collective control mechanism of the Evolution 50 is based on similar design like the Freya, where all control points are in push-pull configuration. However, the Evolution 30 kit would come with the single point collective control mechanism of the original Sceadu. The main frame have servo holes for the configuration of a 3 servo 120 degree ECCPM setup. After the pitch control arm is installed, next comes fitting two "X" shaped levers, the aileron control lever, the "T" push-pull pitch lever and the elevator arm knob onto the pitch control arm. While fixing the two "X" levers, care must be taken on their orientation.
After fitting the rotor head and collective control assembly, I once again skip step to servo and pushrod installation. I use my Futaba 9Z WC2 radio, with Futaba 9252 digital servos on cyclic controls, Futaba 9101 servo on throttle, a GY401 gyro and a Futaba 9250 servo on tail. Servo fitting provides no problem. I did not use the pushrod from stock, and instead I made them by myself using 2.3mm stainless steel rods and Pioneer oil filed links, my preferred combination for pushrods. While fitting the pushrods, especially on the elevator and aileron servo, make very sure that the pushrods are perpendicular to the center screw of the servo, and both linkage are at the same length, or binding would occur. I made linkage pairs using ball link matcher and dial caliper to ensure their lengths are matched. As shown in the instructions manual, the ball holes on the servo discs are not on a straight line to the center servo screw due to the X-lever configuration, so regular servo discs with pre-drilled holes might not provide the exact holes for operation. I uses the Futaba round discs and drill the holes by myself to ensure pushrods are perpendicular to the center screw of the servo. After fixing the linkage, I once again check the operation to ensure no binding is occur. With the pushrod setting as recommended by the instructions, a pitch window of 22 degrees is achieved without binding, which should satisfy all needs. In the Evolution instructions manual there are six pages of radio setup data for Futaba FF9-H, JR X3810 and Sanwa Stylus. The data are very detailed down to the values of ATV, Dual rates for each channel, which made setting up like its being setup by Hirobo staff holding your hands to do it.
After radio setup, I put on the landing gears. Those stock landing gears are kind of high, and looks of the helicopter would be more aggressive if Hirobo include the optional lower profile landing gear (Hirobo 0414-286). The Evolution 50 comes with a new pair of 600mm symmetrical FRP blades. This blade is once again a new product. The blade is light gray colored, unlike most that comes in white. I twist the blades blades with my bare hands and feel that they are quite firm. My digital scale says each weight about 135g, and each one's weight difference is not more than 1/100 gram, which is good. I also find the blades to be balanced. Performance of this new blade have to be tested on flight.
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| FZ-IV rotor head component | FZ-IV rotor head |
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| FZ-IV rotor head | Tapper prep holes |
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| Swashplate and washout assembly | New 600mm symmetrical FRP main blades |
Next comes the assembly of the tail unit. The gear box consists of two pieces of molded plastic that encase the tail gear and fit together alright. The tail pitch change mechanism is the same as the original Sceadu, and in fact the whole tail of the Evolution is much the same as the original Sceadu. The tail rotor has one bearing and one thrust bearing on each side that make tail pitch change very smooth. The tail blades that came stock had very radical design that looks very similar to the "Katana" tail blades of K&S. Tail belt was fine pitch type. The plastic molded tail servo mount is very sturdy and well made, and it hang on the tail boom to give a direct tail pitch control. The whole tail is secured to the boom through 4 hex screws that goes through the main frames, and the tail boom seemed very secure after tightening these screws. There were two tail boom supports to further strengthen the tail boom. The Evolution uses the same tail fins as with the original Sceadu, but I change them to carbon ones of Mr. Carbon for a much aggressive look. After fitting the tail, the construction of the whole mechanics is complete.
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| Tail gearbox | Tail servo mount & boom support |
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| Main frame right side | Main frame left side |
The canopy of the Evolution is the same as the original Sceadu, which is made of "plastic bottle" material. The canopy comes with mounting holes predrilled, so alignment of the canopy to the mounting post is not an issue. The glass part of the canopy comes pre-cut, and is to be secured onto the canopy by eight small screws. The decals of the Evolution are new design, which I think looks much better than the original Sceadu. The decals are very thin and sticky, and adheres to the canopy very well. Holding the canopy in place are six plastic body mounting posts that are on the main frames. Mounting of the canopy to the main frame is by slotting the canopy to four plastic mounting post, and two little post on the middle upper side are used to support the canopy. The extra canopy support is to prevent the canopy from flapping during flying. The canopy is secured by body clips only on the two rear posts. Soft and bigger rubber grommets are used on the canopy, and compared with the original Sceadu the grommet of the Evolution but would not go off easily.
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| Plain canopy | New decal sheet |
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| New body mount post |
After everything is mounted, I checked the CG. Without fuel, the Evolution is a bit head heavy, but with a filled tank the CG is balanced With everything ready and checked, I waited for the test flight to come.
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| Finished assembly | Finished assembly |
At first, I felt it is a bit too sensitive for beginners to learn on hovering, but later I feel that even though the helicopter is a bit sensitive on the hovering side, the control feeling is very solid. One nice feeling of the Evolution is that with its head design the Evolution seems to "self correct" in light winds, while with the same wind condition for the other same size helicopters my fingers should be all over the gimble. On hovering the Evolution has the finesse of a 60 size helicopter, even with the stock head. However, aerobatics is where the Evolution outshines the old Sceadu. Gone are the "flapping problem" evident on the first batch of Sceadu (Hirobo later remedied this problem by changing to stronger parts for export versions...Once again another good excuse to buy from your local dealer that going grey market!), and all controls are very sharp and nimble. The Evolution get to flight speed very fast, even with the stock blades. For F3C maneuvers, the Evolution could execute every maneuver I throw at it, and I feel that in calm wind condition the performance even outshines its bigger brother Freya. There is always lots of power reserve. As to 3D, my only word to describe is "WOW"! At first, I tried to do some flipping with the stock blades, and feel that a pair of stronger and lighter carbon blades would do better, also the tail rotor speed could speed up a little to hold the tail stronger, so I changed to a pair of V-Blades, and changed the tail pulleys to the bigger Freya belt pulleys. My grin went wide after the change....tumbling and flipping seems like child's play. To tell the truth, I actually liked to 3D the Evolution much more than my usual F3C schedule. I tried some 3D maneuvers that I did not tried before, and the Evolution did it with grace and seems to keep asking for more! Its truly a fun machine!
My Sceadu Evolution has been through over 50 flights, luckily without any mishap. I checked the mechanics and found that the main gears wears a little more than usual plastic gears. I think the optional machined delrin main gear and pinion gears (Hirobo part#0412-168 and 0414-169). Also I changed the stock landing gears struts, which wears out a bit already, to the low profile one (Hirobo #0414-286) for a more aggressive look.
Conclusion
The further refinement of the very successful Sceadu into the now Evolution by Hirobo is on the right track. The original Sceadu, albeit a little flaw on the very first batch, is pretty refined already in the latter batch of production. Instead of introducing a completely new kit as the Evolution, Hirobo could keep the "Evolution" parts as upgrade and sell them one by one to make more money, but they didn't. With the Evolution, Hirobo further uped the ante for other manufacturers to follow. The Evolution is one of the few helicopter kits that I did not need put in a lot of upgrade parts to have a very good flight performance. I think with the Evolution Hirobo has once again rule the market of the 32-50 class helicopter market.