The Shuttle Sceadu pronounced as "Skiddy") is Hirobo's newest addition designated to replace their already very successful Shuttle. The Shuttle Sceadu is a completely new design 30-50 class helicopter, aim from entry level to experienced flyers. The Sceadu name is another goddess of Norway, the symbol of beauty and power, the twin sister of "Freya" according to a Hirobo staff. After years of development, it is being debut in the May 2001 Shizuoka Show in Japan officially. The Shuttle Sceadu features the following new designs:
Basically, the Sceadu is just a miniature version of the Freya, except for the push-pull servo control mechanism of the Freya. According to a Hirobo staff, over 70% of parts used in the Sceadu are completely new. Hirobo touted that the Sceadu is easy to assemble, and could perform entry level F3C or 3D maneuvers right out of the box without any upgrade parts. The dimension of the Sceadu are 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 - 8.7:1:4.65
There are 4 different packages of the Sceadu. There is one for both 32 and 50 engines that comes with engine, and the other two that comes without.
Let's take a look at the assembly of the Sceadu.
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| The first view after open the box | All parts neatly packed in bags |
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| Engine mounting for 32 & 50 engines | Canopy |
Upon opening the box, I noticed that the package of the Sceadu is similar to that of the Freya. Gone are the "Jewel Cases" that displayed various metal parts, and are replaced by bags of different sizes. All parts are packed nicely into different bags and according to the steps of instructions too. 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. In my opinion, the Sceadu's packaging is the good in a way that it uses less packaging materials, and retains the ease of assembly by tagging all bags according to the instructions. The instruction manual of the Sceadu is on par with the high standards usual with Hirobo manuals, but this time the English part of the instructions are more clear and not "Jap-ish" that is usually seen in other Japanese made helicopter manuals.
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. Most parts of the main frame were molded in plastic and were of high quality, and everything fit without the use of saw and file. 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 came with all fuel lines pre-cut for suitable length. The front servo tray has a lower portion that had a tub to house the receiver Ni-Cd pack. 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 were to be sandwiched by two plastic main frame halves. Stock Sceadu used metal philips screws to secure the parts, I changed them to stainless steel hex screws for more strength. Since it's a plastic frame, I could secure all screws with Loctite in one shot, without the need to loose them again for alignment. 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 fuel tank was housed in between the lower main frames, and was hold onto position with four rubber grommets. These grommets have to be glued onto the lower mainframes before fitting the fuel tank to prevent them from coming loose. Finishing up the main frame was to put on the canopy mounting posts. Assembly of the whole main frame was so easy that it took me less than half an hour to have it stood in front of me.
The tail pinion assembly of the Sceadu was in fact the same thing as the Freya, with difference in just the size of the belt gear. The whole assembly came fully assembled from the factory, its just a "drop-in" to the main frame. I changed the stock tail counter gear to the machined delrin one for the Freya (Hirobo part #0414-169) for more smooth operation. Like the Freya, I found that the Sceadu 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.
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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 Sceadu was 10mm. Like the Freya main shaft, the Sceadu item also provided two mounting length adjustments (178mm and 182mm respectively). Although the instruction said to use the 178mm hole, it was still possible to use the 182mm hole just by changing four push rods that connects the rotor head to the swashplate. The longer length main shaft setting should provide better hovering characteristics. On interest were tiny groves on one end of the main shaft to designate directions and for better gripping of the washout guide. The dual main gear was actually molded as one piece, so stock Sceadu was not DTDS. I guess Hirobo should have a DTDS conversion kit for the Sceadu in due course. I found that the main gear hub of the Sceadu was the same dimension as the SE hub for Shuttle, so I exchanged the stock plastic Sceadu main gear hub with a aluminum SE hub, and used a Correct adjustable LSD clutch for adjusting the tail power during autorotation for the moment before the DTDS introduce. Finally, I replaced the stock collar with a "clamp on" style one from Correct to prevent denting on the main shaft.
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| Main drive train | Note fake DTDS system |
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| Counter gear assembly same as Freya | Note Correct LSD system |
Next came the assembly of the FZ-III rotor head, swashplate, and the mixing sliders. I noticed that Hirobo did not go cheap with the Freya because all rotation points were equipped with bearings, and the main blade grip had thrust bearings. Although the manual did not mention, there are two settings available for sensitivity of rotor head control to suit different needs, and I used the manual recommended setting for the moment. The flybar paddles are the ones from RGM and GPH, that weight of the paddles could be adjusted. After assembly, I put the rotor head on a high point to balance. As to the mixers and the swashplate, they were 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 CA glue to fix the screws for more strength.
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| FZ-III rotor head | Swashplate & washout unit |
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| SE flybar paddles | Molded head button on top |
Then, back to the main frame, where various mixers and the pitch control arms are to be fitted onto the frames. The pitch control arm of the Sceadu was based on similar design like the Freya, except that the pitch control arms in the Sceadu were molded in plastic. One thing of notice was that after the pitch control arm was installed, it occupied an opening which should have been made to house a servo. Hirobo should not be making an extra servo hole here just to get it occupied by the pitch control arms, something smells here... Might this servo hole is designed for something that was coming for the Sceadu? Maybe a CCPM conversion??? Looks logical to me, cause this servo hole is the best place to house a servo for the 12 o'clock position control point of a 3 servo 120 degree CCPM setup. Actually, the Sceadu's servo placement resembles the Freya very much, and since the Freya had a CCPM conversion, I think there should be one for Sceadu too. Anyway, after the pitch control arm was installed, next comes fitting two "I" shaped levers, the aileron control lever and the elevator arm knob onto the pitch control arm. The cyclic control of the Sceadu reminds me of the old Hirobo Eagle.
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 was similar to the Freya, and in fact some parts were borrowed from the Freya parts bin. 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 tail boom was round shaped, in exact the same diameter as the ones used in the old Shuttle, but longer. The plastic molded tail servo mount is very sturdy and well made, but I changed that to a metal/carbon one from Hirobo. On the end of the tail boom that goes into the main frame I wrapped it with duct tape for better security. The whole tail was 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.
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| Tail gearbox | Tail servo mount & boom support |
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| Tail fins | Tail rotor & blades |
Next came fitting the engine onto the main frame. Actually, the main difference between the Sceadu 30 and 50 is that each had different engine mounting part for their engine, all other parts and the dimension between the two are the same. I have parts for both 30 and 50 engine, and I decided to use a OS50 engine. The clutch hub was installed onto the engine's crankshaft by screwing itself onto the crankshaft, and the use of a Hirobo clutch hub tool was recommended. If the hub was made correctly, there was absolutely no need to dial indicate the clutch hub. The clutch, which was a hefty one, sat on top of the clutch hub. Gone was the one way bearing as seen in the clutch of the old Shuttle design, and replaced by a fixed shaft on the clutch for linkage 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 would sit 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. All parts fit without a problem. After securing the engine onto the main frame, I found that the fan shroud did not extend to cover the engine's heatsink, and in fact, the whole heatsink was exposed, just like the Freya. I would try to fix that later.
Either Sceadu's came with a muffler in their box. I found the stock muffler be too restrictive, so I used a K&S muffler for exhaust, and it fit no problem. I connected a K&S header tank and all fuel lines were being connected to the engine. The Sceadu main frame had a very nice fuel shut off valve built in, where an opening like a "tear drop" was located conveniently near the fuel inlet of the carburetor, with the fuel line went through this opening. Fuel cutoff and release was just by sliding the fuel line up and down the "tear drop" hole, a genius design! I checked the inside of the "tear drop" hole and found that its smooth enough not to cut into the fuel line, but nevertheless I used a file to further smooth things out.
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| Parts for mounting OS50 | Hirobo tool used to mount clutch hub |
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| Engine assembly | K&S muffler |
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| Header tank | Note fuel cutoff on main frame |
Servo installation comes next, and it was also a no-brainer. I use my Futaba 9Z WC2 radio, with JR DS8201 on the cyclic and throttle, a GY401 gyro and a Futaba 9253 servo on tail. One thing to praise about the Sceadu especially was that this time servo installation was a breeze, many thanks to the inclusion of appropriate length servo mounting screws. For other Hirobo machines, servo mounting screws were only long enough to mount Futaba servos, and if you use JR servos which had thicker mounting grommets, tough luck, you would need to buy a whole set of mounting screws! I told Hirobo guys many times about this problem, and glad to see they took my advice that starting with the Sceadu longer servo mounting screws were used to make JR servo users happy! (Not even the Freya EX, that was introduced around the same date as the Sceadu, had long servo mounting screws for JR servo).
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. Stock Hirobo machines all used 2.0mm thickness black metal pushrods that were easy to bent, and this was the second thing that I preached Hirobo for a change for some time, let's see if they would take this advice... Actually, there was not much ball links to made, because with the Sceadu some links were being molded at a fixed length. I also changed the stock metal tail linkage to a carbon wire.
Lacking in the Sceadu instruction manual was the very detailed setup data for all makes of radio as seen in the Freya's manual. While the Sceadu manual did provide detailed setup instructions, the manual of Freya provided a lot of details for all makes of radio which made setting it 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 Sceadu would be more aggressive if I use a lower profile landing gear. Depend on the package, Sceadu 30 came with 550mm wood blades, and Sceadu 50 came with 570mm FRP blades. I used the FRP 570mm blades, which had proven performance in my Shuttle RGM.
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| Main frame before setup right side | Main frame before setup left side |
The canopy of the Sceadu was made of "plastic bottle" material, and in my experience these took long time to prepare, and sticker would not adhere to it very well. I was wrong with the Sceadu canopy in this respect! The Sceadu canopy came with mounting holes predrilled, and even though I needed to use a razor to cut excess materials off the canopy molding, the cutting was very easy and did not require much force that was usually needed with other plastic bottle type canopies. The glass part of the canopy came pre-cut, which was another plus. The glass part was to be secured onto the canopy by small screws. The shape of the canopy was sleek and good looking, very much like the front part of the Nova 3. Next comes to applying decals, they were very thin and sticky. The decals adhere to the canopy and fins very well. The Sceadu tail fins had tubs on their surface, which being cut void would result with 3D fins with holes. I opted to leave the fins as is. Mounting of the canopy to the main frame was by slotting the canopy to the four plastic mounting post, and secure by body clips usually being used for r/c cars. Soft rubber grommets had to be mounted on the canopy, but they would go off easily. I put on some oil on the inner side of the grommet, and file the head of the body mounting posts down a bit to ease canopy mounting. To my surprise, it took me less than two hours to made Sceadu canopy, which was a record of mine for plastic bottle typed canopy.
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| Plain canopy | Finished canopy |
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| Canopy mounting grommet easy to come off | Canopy mounting with body clip |
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| Trimmed canopy to clear muffler | Tail fin with decals |
After everything is mounted, I checked the CG. Without fuel, the Sceadu would balance, but with a filled tank the tail would be a bit heavy. I put on about 30 grams of weight onto the tip of the canopy to make the Sceadu balance. With everything ready and checked, I waited for the test flight to come. It just take me about 5 hours of work time to fully assembled the Sceadu, which was a record in itself. The assembly was a breeze!
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| Finished Sceadu | Finished Sceadu |
On one sunny, calm day I take the Sceadu to the field for some hovering and trimming. I intentionally set the mixture a bit rich to run-in the engine. When I increased the throttle, the Sceadu left the ground. Hovering is rock stable. I felt that the head was quite sensitive to winds. I could say on hovering the Sceadu is on par with the old Shuttle. I also tried some aerobatics with the Sceadu, and found that its in the aerobatics that the Sceadu truly shines. Tracking are straight, and forward flights are fast. As of today, I have burnt a bit less one gallon of fuel with the Sceadu, so I could not say more about the Sceadu's performance, but in due course I would update this part to include more.
Personal opinion, I think the Sceadu, which is due to replace Hirobo's very successful Shuttle line, is very refined. All the mechanics are logically designed, and it has almost all the features that a good, high performance helicopter should have. With the Sceadu, Hirobo takes away the problem of the old Shuttle (Way tail heavy, thin main shaft, non-CG mounted fuel tank, non-driven tail during autorotation), and further refine it to be a well balanced helicopter that sells at the same price of its pre-decessor. It is no easy task at all, and Hirobo executed that right on. Looking back at the Shuttle's history, it is the most selling, most popular helicopter design to date. With the Sceadu, Hirobo have taken a great leap forward to the new millennium, and have upped the ante on entry level helicopter design for other manufacturers to follow.
Part Two of Sceadu review coming later!