It has been a little over 2 years since SAB released their first Goblin Urukay in two different colours, red and blue and two different rotor heads, two or three bladed. This year SAB stepped up to their latest model, the Urukay Carbon Edition and Carbon Ennio Graber edition. The idea behind the original design of the Goblin Urukay was to make a helicopter targeted towards F3C flying while also maintaining a quite capable 3D flight performance model. This ‘hybrid’ design ultimately proved to be quite successful and makes the Urukay one of the best selling models in the SAB Goblin range for this flying style. In this review we want to show you in detail the most versatile machine ever made. Following the concept of the original Goblin Urukay this brand new Goblin Urukay Carbon Edition has some some significant improvements, the Urukay Carbon delivers some structural improvements, new F3C rotor head enhanced streamlining and an all-out increase in performance.
SAB presented their first prototype at the F3C World Championships in Brescia, Italy (2011). But it was really unveiled two months after at the famous Alpine Heli Smackdown (Switzerland). There all the pilots could see a helicopter, which was totally different from what we have ever seen, it was called the Goblin 700, a helicopter from the famous blades manufacturer SAB. I remember my first thoughts when I saw this helicopter: it’s a strange but very nice looking helicopter.
Until then all the pilots thought that „acrobatic scale fuselages“ were destined for F3C competition. King of 3D, Tareq Alsaadi was in that time sponsored pilot with Outrage. SAB prepared a Goblin 700 to be flown by Tareq so he could show that this helicopter was born to perform extreme 3D. They did the test flight in front of a lot of public and he just performed an amazing flight! From that moment onwards Goblin was a revolution! That heli captivated all the pilots in the world and became a world wide super sale. After five years SAB Goblin launched a full range of model going from a Goblin 380 up to the massive Goblin 770 and for the F3C pilots the great Urukay. But now its time for the evolution of the well known Urukay to a specially designed machine with the help of world class pilot Ennio Graber. The Italian owners of Goblin Stefano Baiardi and Enrico Bernabei marked a before and after in the design of RC helicopters.
This Goblin is a helicopter with very peculiar flying characteristics. It is stable, agile,fast, and powerful at the same time. The flying style of this helicopter is very different from the rest. No doubt that is a very special helicopter.
Thanks to its design, the performance level is very high. It uses a belt drive system that efficiently transfers engine power to the rotor. The motor pinion uses a belt that moves a 60T pulley. This pulley has mounted below one transmission pulley that drives the tail-belt. At the top of the pulley we have the steel helical pinion that attacks the main gear, which eventually moves the rotorhead. This system is patented by the company of SAB.
The servos are mounted horizontally around the matt black 120° CCPM swashplate. The BK 8002HV Servos are connected directly to swashplate with a linkage rod. This forms a very rigid and accurate assembly. The whole assembly comes higher then for example the Black Thunder were you want the maximum lowest center of gravity, and increase performance to the max. With the Urukay we have a higher head which makes the model much more stable then with a lower rotor head closer to the frame.
As with all the Goblins the important part of the mechanism is the central part consisting of a aluminium frame tray, main servo mount and motor mount. Here we install the servos, motor, gears and pulleys. This frame tray is easily removable for maintenance.
The tail uses a simple belt drive system with a special tail belt idler. Designed to work at 12S (44.4V). Current Brushless motors are very powerful, and it is important to take advantage of that energy. With double belt system, the Goblin Urukay handles this energy very efficiently.
The Italian design is unique. Visually its very attractive as the canopy binds completely with the tail boom made fully of carbon fiber. Its streamlined design gives the Goblin incredible aero dynamical capabilities. The tail system eliminates vibrations of the tail rotor at high and low rpm. It is strong and lightweight.
One of the main highlights on the new Urukay Carbon Edition is without doubt the new HF3C (High Precision F3C Head System) rotor head that comes with matt black components. This new head HF3C rotor head (2 blades) was developed together with Ennio Graber for the best result in F3C style flight. More details on this rotorhead later.
SAB is known worldwide for manufacturing RC carbon fiber blades. The Goblin had to include them. In the box we find a set of the new Thunderbolt 730TB main blades specifically designed for F3C competition and 105mm tail blades in black, white and red colours.
The kit is presented in a professional manner and comes in a very very big box. When we opened the box, we find high quality CNC aluminium and carbon fiber parts. The CNC parts come protected in foam trays to avoid scratching. The rest of the parts some all well marked in plastic. All are numbered and correspond to the assembly procedure manual.
The manual is visually appealing, it’s printed in full colour. Inside we find can find the different ratios and configurations suggestions. It is very important to choose the correct ratio that maximizes efficiency depending on the motor, pinion and rpms we want to fly.
SAB also included a useful sheet with points to be reviewed during maintenance. Includes a full list of spare parts with images which is very useful when we need to order any part.
The goblin is a helicopter which needs regular maintenance and does not only need to checked after a crash. Therefor SAB has included a sheet that explains the important parts to check.
The frame is composed of two carbon fiber sides on the Urukay Carbon Edition it now comes with a matt black finish, it really looks high class. At a first glance it looks weak, but after mounting all the inside parts its really reinforced. The new frame is compatible with ESC in top position and ESC in bottom position. The carbon fiber battery tray is anchored to the frame and has several positions, depending on the size of battery packs and were we build in the ESC, we can locate it in 6 different positions to achieve a perfect center of gravity. The landing gear remained the same on the Carbon Edition as with the Urukay Competition, it’s a very low profile one piece landing gear painted in the same white colour as the fuselage. The landing gear is mounted directly to the frame with two aluminium landing gear support brackets.
Its very well explained in the manual were to put which glue or locktite but we always recommend those screws threaded into metal to apply a little lock tite to the screws. It is very important to use it well to prevent stripped bolt heads or broken screws. Its sufficient to apply a little on the tip of the screw (aprox.1mm).
Once you have installed this we start with the main structure of the frame. The Goblin comes with a central CNC aluminium frame tray. This structure comes standard with two bearings mounted. On this tray we need to mount the full transmission system on a later stage. Now we mount the main servo mount onto the frame tray with four special aluminium spacers and we mount the servos the mount. The servo support is fully made of CNC aluminium and comes with two bearings though which on the 12mm main shaft passes, and through the other one a 10mm secondary shaft to hold the drive pinion and the One Way pulley.
Some parts are factory pre-assembled. I always check everything to ensure the correct assembly and if threadlock is applied. To join the frame tray and servo mount it uses 4 aluminum spacers. The carbon fiber anti rotation guide is mounted to the servo tray. The 68T main drive gear is helical. The Urukay Carbon Edition comes with a new version of the tail belt idler and is mounted on the lower part of the frame tray. The tension of the tail belt idler is adjusted by turning the belt idler which tensions a spring. The SAB manuals one of the best I’ve seen with very clear and detailed drawings. The manual indicates us that we have to grease the one way bearing of the 60T pulley and on the main gear, we recommend to use Dryfluid Heli and Gear Lube here, in our opinion its one of the best grease on the market.
The wiring is a very important part on this frame, you should spend time to prevent rubbing of the cables on the on transmissions and frame edges. The motor mount is located in the front of the frame. Damping springs are used. Depending on which motor we mount we have to take into consideration the length of the motor shaft, the manual gives you the ideal length so its easy to find the appropriate shaft or shorten the one already on the motor. If it is too long you are not able to place the battery protection plate and may rub on the batteries, and this is a big problem. The manual advises cutting the shaft with a Dremmel to the right size. The kit comes with a 20T pinion. In my case and after recommendation of Ennio Graber I mounted the optional 22T pinion to achieve the 9.8:1 ratio and get 1900 RPM maximum with the Kontronik Pyro 750-50 motor. The motor pinion does not attack directly the main gear but uses a belt drive system.
Matt Black HF3C Rotor Head
The Goblin Urukay Carbon Edition comes standard with the matt black HF3C rotor head. The HF3C rotor head (2 blades) was developed for the best result in F3C style flight. This head has been developed in corporation with world champion in F3C class Ennio Graber in order to increase stability and the usable rotor RPM range.
The HF3C rotor comes different from other Goblins not pre assembled in the box. I personally prefer this as the manual explains very well where we need to apply thread lock, grease and how to assemble it the correct way. The rotorhead consists of the new HF3C center hub which is wider then a standard center hub, the new blade grip arms go much further out to give it a different geometry and make it more stable, radius arms, linkage rods and 80 Shore red dampers. It is possible change the rigidity of the dampening system acquiring additionally H0482-70 (Yellow), H0482-90 (Green), for change the head characteristic.
Dampers used are made from very rigid rubber and are mounted inside the center Hub. Its recommended to put a small amount of grease inside the hub and on the damper so the feathing shaft can be place more easily. Each blade grip has two radial bearings and one thrust bearing. In kit includes several washers to control the play of the spindle shaft. In the manual recommends using one 1mm washer and one 0.2mm washer on each side. If the blade grip feels very rigid we need to removed the 0.2mm washers. Its recommended to check for axial play of the spindle after the first flights. If the play has changed you can add one or two 0.2mm washers.
The linkage system used is with turnbuckles. In the middle of the linkage we can find a small hole through which you can pass a 1.5mm hex driver to accurately adjust 0 pitch on the head.
The swashplate on the Goblin Urukay Carbon Edition comes also in a matt black colour to match the rotorhead.
Boom & Tail
The tail is one of the characteristic items of a Goblin. The boom has nothing to do with a traditional tail boom. SAB manufactured a oversized fully carbon fiber tail boom which comes factory painted to continue the colours of the canopy. It is rigid enough so no need for tail boom supports. Another curiosity is the way it anchors into the frame with a aluminium guide into 2 plastic nylon screws. The kit includes a special plastic tool for this. The goal of this anchoring system is that when you crash the screws break and saves the tail.
The tail servo is mounted with a special aluminium tail servo support in the lower back part of the main frame and not in the tail boom as usual with Goblin. More or less in the lower part of the center of the boom we need to mount the tail push rod guide. The tail push rod is made carbon fiber and SAB recommends a little lubrication on the push rod were its supported by the tail rod guide. It is important to protect the tail servo cable and use some servo braid to avoid the cable can be damaged by sharp edges on the carbon fiber.
Nowadays we are very used to see all the helicopters using torque tube drive system but the Goblin uses tail belt drive. The overall design is very simple and easy to assemble with very few parts. Most of the parts like the locking reinforcements and tail servo locks come pre-assembled by the factory in the box. Although you need to check everything and ensure correct installation. The tail rotor assembly does not come in matte black aluminium but in carbon fiber. It uses a traditional double tail pitch slider. The tail box is formed by two carbon fiber tail plates. To mount the whole tail case its done by 3 aluminium spacers. The tail uses a 25T pulley on the tail.
The basic setup of this model used in this review is the following with a Spektrum transmitter and Spektrum AR7300 BeastX Flybarless system.
Since F3C is new for me and this is my first Goblin Urukay I have ever build I was unsure about the settings and setup so I took up on the advice of Ennio Graber to setup my Urukay as a starting point. Every pilot has its own settings to be honest but its always good to have a good starting point from were you tweak the settings until you like it for your flying. We tested various settings and this is how we liked it the most: We changed menu B into transmitter mode. The dual rates are set to 100%, exponentials for hovering manoeuvres on Ail, Ele, Rud to +40% and for all the other manoeuvres we use a little less exponential +30% on Spektrum in case of Futaba this value should be negative. For the tail we are running approximate 44% in idle up 1 and 56% in normal flight mode. The tail is very fast so we needed to reduce the endpoints (ATV) from 100% to 80% on rudder. We used a Kontronik Kosmik 200Ah so we can set 3 head speeds using straight linear throttle curves and programming the Kosmik with Mode 4. The correct ratio as previous explained with a 22T pinion and a 500KV motor is 9.8:1. With this setup we can reach a maximum head speed without governor overturn of approx. 1900RPM, this was the range I wanted to fly this helicopter.
The throttle curve is set the following way, we used the straight linear throttle curves in mode 4 on the Kosmik speed controller. The motor has 500KV and we used a 12S setup with SAB Lipo 5250mah 50C packs and the 22T pinion.
|Idle up 1||75%||75%||75%||75%||75%|
|Idle up 2||77%||77%||77%||77%||77%|
|Flight mode||Aprox. RPMS|
|Idle Up 1||1900rpm|
|Idle Up 2||1950rpm|
Pitch curve have been set in all flying modes to -12.5 at low stick, 0 at mid stick and +12.5 at high stick like recommended in the manual.
Initially we programmed in normal flying mode 1450 rpm. During hovering the Goblin Urukay behaved very stable. With these RPM´s the behaviour of the helicopter is very smooth and predictable and perfect for the stationary manoeuvres in F3C.
To do the more big air manoeuvres we needed more head speed so we activated idle up 1 raising the head speed to about 1900rpm. I started doing some fast forward flying and the heli traced a perfect straight line without any strange tendencies. I really liked the smooth sound coming of this heli. It is noticeable that this heli can reach very high speeds thanks to its aerodynamic shape. Stability and manoeuvrability is superior to any big sized helicopter I have tried sofar. Thanks to its design, it has fantastic visibility in flight in all directions.
The cyclic response is perfect in my opinion although I just started getting into the F3C world. The flight characteristics offered by the HF3C rotor head is very good with a different feeling then flying with the traditional Goblins in a similar size. In my opinion the HF3C rotorhead is the perfect mid way between a aggressive and smooth, precise flight. The Goblin Urukay Carbon is extremely agile and fast with a very smooth flying style. The tail performs well in all kinds of manoeuvres but also at lower and higher RPM. The dynamics with MICROBEAST is perfect. Although nowadays the torque tube is the most widely used in helicopters, I must say that the belt works pretty well.
The kit includes a sheet named (important tips for proper assembly). Here SAB explains some of the key points of the helicopter where you should pay attention. Although helicopters are prepared today hold out almost everything we need to have in mind that parts will have wear and require maintenance. Sounds like a good idea that SAB includes a sheet with Tips & Tricks.
If you’re even thinking about giving F3C flying a go, its certainly worth giving the Goblin Urukay Carbon some serious consideration. Why? Because it’s a stable platform for the precision maneuvers, tracks like a bullet for the big air routines and is more than capable of breaking out the 3D when its show-off time. I guarantee you are going to love this machine.
In the next issue we will publish an exclusive interview with factory pilot Ennio Graber who will give us some additional information about the Urukay Carbon Ennio Graber edition, his settings and tip and tricks. So don’t miss it!
The new Thunderbolt Blades
The „SAB Thunderbolt Blades“ are made to grow the performance of your helicopter. The amazing design was developed not only for an esthetical purpose, but it also improved the visibility of the tip of rotor, higher visibility is necessary in very low manoeuvres. The variable profile along the radius of the rotor makes the „SAB Thunderbolt Blades“ 20% more efficient in comparison to the „SAB black line blades“ and gives great stability to the whole helicopter without compromising the agility of the rotor. The chord varies along the radius of rotor (Shorter at the root, larger at tip); thanks to the aerodynamic of the rotor, gives more thrust exactly where the rotor generates it, that allows harder and more precise manoeuvres in flight. To improve the stiffness the „Thunderbolt Blades“ includes double layer of unidirectional carbon fiber.
In order to guaranty safety in the event of a crash, we include a steel safety wire alongside the leading edge of the blade.
SAB GOBLIN URUKAY CARBON EDITION ENNIO GRABER
- Main rotor diameter: 1654 mm with 730 mm size blades
- HF3C Head (p/n H0825-K)
- Main blade length: up to 750 mm
- Tail rotor diameter: 284 mm with 105 mm size tail blades
- Main shaft diameter: 12 mm
- Tail shaft diameter: 6 mm
- Spindle shaft diameter: 10 mm
- Gear Ratios 8.6-11.9 : 1
- Weight including electronics: 4280 g (excluding flight battery)
- All pulleys are made for 6 and 8 mm motor shaft
- Cyclic Servos: Standard size (40mm)
- Tail Servo: Standard size (40mm)
- Typical battery setup: 12S (from 5000 to 5800)
- Typical ESC setup: 120 – 160A.
- Motors: (Max Diameter: 64 mm, Max Height: 64 mm)
- Battery compartment: until 75x58x350mm
Manufacturer: SAB GOBLIN
- 730 mm ThunderBolt F3C dedicated main blades
- 105 mm ThunderBolt tail blades
- Motor Pulley 20T (other pulley sizes available)
- 2 Sets Battery Tray
- Blades: SAB Thunderbolt 730mm
- Flybarless: Spektrum Microbeast Flybarless
- Cyclic servo: BK Servos BLS8002HV
- Tail servo: BK Servos DS-7006HV
- Battery: 2x SAB Lipo 50C 5250mah 6S
- Motor: Kontronik Pyro 750-50
- ESC: Kontronik Kosmik 200Ah
Ennio Graber say:
The new Goblin Urukay Carbon with its important changes, improves an already successful helicopter and makes it the pinnacle for competitions.The differences and versatility of the Urukay Carbon allow you to experience a new dimension of model helicopter flight.