TBS Caipirinha Flying Wing Build & Review

One of my winter projects for 2015 has been to build a small (less than a metre wingspan) flying wing which can carry a HD camera and be easily transported. After researching what was available, it came down to a choice between the high-end TBS Caipirinha by Team BlackSheep or the budget-concious HobbyKing Teksumo kits. I decided to go with the Caipirinha as it has a purpose made GoPro nose mount and I wanted to see if TBS products lived up to their reputation. In this article I unbox, build and flight test the Caipirinha EPP electric wing.

Specifications

The Team BlackSheep Caipirinha is manufactured by WindRider, in co-operation with RiteWingRC (producers of the popular Zephr range of large flying wings), and is sold both by TBS in their online store and various retailers worldwide. The Caipirinha is sometimes referred to as the TBS Caipi or TBS Capy. The airframe shown in this review was bought from ElectricWingMan for £72.50, not including delivery costs.

This aircraft is only manufactured in kit form, which means that all electronics (motor, servos, etc.) must be purchased separately. TBS do however sell two special ready-to-fly versions of the Caipirinha in their online store. Also available from TBS is an electronics package for the Caipirinha to simplify choosing which components to use with the wing.

The Caipirinha has a wingspan of 865mm, a length of 415mm and a maximum wing thickness of 52mm. A fully built wing (with all optional reinforcement spars) weighs approximately 180g, while the final flying weight will typically come in at around 600-750g depending on the components used. The wing is available in black or white EPP (expanded polypropylene) foam, although the white version seems to be harder to find.

This wing was originally designed a few years ago for use with 2S LiPo power and the GoPro Hero 2 camera. In 2014, the Caipirinha design was updated to also support the smaller and lighter GoPro Hero 3 range of cameras. Using 3S LiPo power has also become a popular option. The completed plane as reviewed here had the following specifications:

  • TBS Caipirinha black FPV wing (via ElectricWingMan)
  • Tiger Motors MN2206 2000KV brushless motor (via ElectricWingMan)
  • TBS Core PNP25 on-screen display (via HobbyKing)
  • Turnigy Plush 18 amp ESC (via HobbyKing)
  • Turnigy Nano-Tech 2S 3300mAh 35C battery (via HobbyKing)
  • 2x Hitec HS-65HB Karbonite micro servos (via local dealer)
  • Skyzone TS58500 32CH 5.8GHz mini video transmitter (via HobbyKing)
  • GoPro Hero 3+ Black HD camera
  • Sony 960H CCD Effio-V 800TVL FPV camera (via SurveilZone)
  • FrSky Delta8 2.4GHz Radio Control Receiver (via HobbyKing)
  • Hitec Aurora 9X Radio Control Transmitter (via local dealer)

Unboxing

The Caipirinha was delivered on time by ElectricWingMan and shipped in the diminutive white cardboard box shown below. The wing is manufactured in two halves, so the packaging for the kit is quite small.

TBS Caipirinha box contents.

Although all of the kit parts are placed loosely in the box, they are sufficiently tightly packed to not move around and become damaged during shipping. Having opened the package, I was pleased to see there were no missing parts or damaged items.

TBS Caipirinha unboxed.

The above photo shows all of the accessories that are included in the kit. The wing features pre-cut foam recesses for electronics installation and wiring. Also included are the ‘negative’ foam pieces should the owner want to fill in any of these recesses. The elevons are constructed from balsa wood, covered in model film. Three carbon fibre ribbons and two tubes are included for reinforcing the wing. Two different pairs of wing stabiliser tips made from corrugated plastic are included, along with 1:1 scale paper templates to produce more (not pictured). No printed instruction manual was included with the kit, but one is available on the TBS website.

TBS Core PNP25 OSD package.

Although I did not choose to buy the purpose made TBS electronics package for the Caipirinha, I did buy the TBS Core PNP25 on-screen display system, which is a perfect match for this airframe. It was delivered from HobbyKing in an antistatic bag, which included a pigtail lead for connecting the RSSI input port to a receiver. I was a little disappointed to see that the PNP25 unit does not ship with any Molex ‘PicoBlade’ connectors for connecting the unit to an FPV camera and video transmitter. These cables are included with the TBS cameras and video transmitters, but as I am not using those, I had to buy these separately from eBay.

Design & Assembly

The Caipirinha wing is composed of two halves of good quality EPP foam, which feature neatly cut out recesses for the servos, radio control receiver, FPV camera and video transmitter. Laser cut plywood parts are included to assemble the GoPro camera mounting box and motor mount. The battery and camera box are positioned front-centre on the wing, while the video transmitter and RC receiver are on opposite sides of the wing. This placement follows the standard practice of trying to keep these two items as far apart as possible to avoid interference.

I was very impressed with the Caipirinha instruction manual, which is detailed, well illustrated and clearly written. Team BlackSheep deserve credit for investing in producing good documentation, an area where many model kits are let down.

The overall assembly process involved attaching the wing halves together, adding the desired amount of carbon fibre reinforcement materials, attaching the elevon surfaces and fitting the electronics components.

TBS Caipirinha wing sections (unassembled).

The EPP foam used by TBS has been coated in a very thin lamination film to provide extra strength and protection for the foam. This also means that the wing can (if desired) be painted using any conventional spray paint product.

TBS Caipirinha wing sections dryfit (top).

The two halves of the wings slot together easily and accurately. For this build I will be using Gorilla Glue, which is an expanding water activated glue very well suited to use on EPP foam.

TBS Caipirinha wing sections dryfit (bottom).

In addition to the carbon fibre reinforcement tubes, there are interlocking tabs in the foam which can be seen on the underside of the airframe as shown above. The carbon fibre reinforcement ribbons and tubes do not all need to be added to the model, depending on what style of flying the model will be used for. As I want my wing to be as robust as possible, I decided to use all of the tubes and ribbons.

TBS Caipirinha wing sections (assembled).

After dry fitting the wing to check the two reinforcement tubes fitted correctly, I joined the wing permanently using water activated Gorilla Glue and fitted the reinforcement ribbons. Having a water spray bottle available to mist water in to the holes and recesses where the glue will be used is useful at this point. This type of glue will slowly foam and expand as it cures, which takes several hours.

TBS Caipirinha wing sections (assembled and taped).

After the glue had fully dried, it was necessary to trim some excess glue from the underside of the wing where it had foamed out of the recesses. I then covered the glued areas with black wing tape to keep the underside of the wing aerodynamic.

TBS Caipirinha camera boxes (original and 3D printed).

While the glue was curing, I assembled the laser cut plywood camera box using cyanoacrylate glue and painted it black. It is important to pay close attention to the instruction manual here, to avoid putting the camera box together back-to-front. Different width sides for the camera box are provided, for both the older GoPro Hero 2 camera and the smaller GoPro Hero 3 (pictured). I also 3D printed a spare GoPro camera box which I found on the Thingiverse website while searching for Caipirinha parts.

TBS Caipirinha motor mount and 3D printed wall hanger.

Similarly, the plywood motor mount must be assembled and optionally painted. Another interesting part I found on the Thingiverse website while searching for parts was the wall hanging bracket for the wing, pictured above. This allows the model to hang from a wall by the propeller.

TBS Caipirinha motor mount (assembled).

The motor is bolted to the wooden motor mounting using the fixtures included with the MN2206 motor and secured with some of HobbyKing’s blue thread-lock liquid. After taking some measurements on the wing, I trimmed the ESC leads to the correct lengths, soldered the motor to the ESC and added a JST battery connector. Before soldering the motor leads, I used a servo tester to check the motor was spinning in the correct direction.

The TBS instruction manual suggests using a 12 or 18 amp ESC when using 2S LiPo power. I went with the 18 amp option to include some extra safety margin in the power system, although after seeing the current consumption figures from the OSD during flight, the 12 amp ESC would have been entirely sufficient and added less weight to the rear of the wing. Conversely, using an 18 amp ESC should provide me with enough headroom to try 3S power in the future without needing to upgrade the ESC.

TBS Core PNP25 wiring loom.

As the TBS Core PNP25 unit uses Molex PicoBlade 1.25mm lead connections (also known as micro-JST), I had to solder custom wiring harnesses to connect the SkyZone video transmitter and Sony CCD camera to the unit. An advantage of having to do this meant that all of the wiring on the wing was not any longer (or heavier) than necessary.

The pin-outs for the PNP25 are not marked on the sockets, so I had to disassemble the unit to inspect the PCB markings. I was relieved to see that the connections were properly annotated in the silkscreen on the PCB, as there is no PNP25 manual available on the TBS website. While the cover was removed from the PNP25, I changed a solder jumper to set the camera power supply voltage to 12V (it is set to 5V by default), which is required by the Sony CCD camera.

TBS Caipirinha motor mount (installed).

Continuing with the wing assembly, the next step was to glue the motor mounting to the wing using cyanoacrylate glue. The instruction manual provides helpful illustrations on how to correctly position the motor mounting so that the thrust angle of the motor is correct. When using cyanoacrylate glue on something like this it is always a good idea to practice dry fitting the parts as the glue will set very quickly, and getting the angle of the motor mount wrong will seriously impede the flying capability of the aircraft. With the motor mount installed, I secured the Turnigy Plush ESC to the wing using a small amount of self adhesive Velcro.

TBS Caipirinha GoPro camera mount (installed).

Moving to the front of the wing, the plywood GoPro box is glued in to position using more cyanoacrylate glue. A Velcro strap is included in the kit for securing the camera inside its box, which is placed underneath the camera box when it is being glued in position. Two tabs on the back of the camera box slot in to the wing to help align and secure it.

TBS Caipirinha assembly..

Using the wiring harnesses produced earlier, I then proceeded to fit all of the remaining electronics parts to the wing. The TBS Core unit fitted perfectly in to a recess next to the video transmitter, leaving the three mode switches facing upwards, flush with the wing surface. The servos, video transmitter and FPV camera all required slight cutting to the foam before they would fit tightly in to the wing. Components were either secured in place with small amounts of cyanoacrylate glue, hot glue or self adhesive Velcro. It’s important not use cyanoacrylate glue to secure the board camera as the fumes from the glue can create a haze over the lens.

The pre-cut recesses in the foam made installing the components very easy. The FPV board camera is set back in to the wing slightly to protect the lens in the event of a crash. Using a 2.8mm lens is recommended as this will avoid having any of the protective foam visible in the camera’s field of vision.

TBS Caipirinha elevon fitment.

Once the electronics components were installed, I taped the two elevon surfaces to the wing. Again the instruction manual provides a detailed illustrated explanation on how to do this correctly. I used 1” 3M Blenderm tape to affix the elevons. The control horns are then glued in to precut holes in the balsa wood. As with all control horn fitments, it is important to make sure that the holes in the horn are directly above the control surface hinge.

TBS Caipirinha recess taping.

To round off the build I covered the various recesses and channels with more black wing tape to improve the airflow over the wing. The 2S 3300mAh Nano-Tech battery I chose for this build ships with bullet connectors so these needed to be changed to use the smaller JST connector required by the TBS Core PNP25 unit.

TBS Caipirinha balancing test with large allen key.

At this late stage in the build I wanted to see how well the wing was going to balance on the recommended centre of gravity with my selection of components. The manual recommends targeting a centre of gravity of 135mm, which I marked on the underside of the wing using stickers. As the TBS Caipirinha was originally designed around the heavier GoPro Hero 2 camera, it was not surprising to find that the plane was tail heavy at this point. I found the weight of a large Allen wrench (103g) over the battery was necessary to balance the wing. Rather than add such a large amount of ballast to the wing, it is recommended in the instruction manual to move the battery bay forwards to help balance the wing.

TBS Caipirinha balancing.

Shown above is the battery bay moved forwards by about 10mm by cutting foam from the front of the battery bay and gluing it in position at the rear of the bay. There are two holes in the battery bay for the battery strap to go through, which also need to be relocated further forwards. Moving the battery by this small amount made a big difference to the amount of ballast required to balance the wing, reducing it to about 20g.

I cut shallow recesses under the battery area to fit some lead weight. With flying wings it is important the wing is balanced both front to back and side to side, so different amounts of weight were placed on either side of the battery bay.

TBS Caipirinha battery relocation.

This photograph shows the final position of the battery after the bay was modified.

TBS Caipirinha battery relocation (bottom).

The plywood battery strap plate on the underside of the wing must be moved forwards by the same amount that the battery bay is moved.

TBS Caipirinha wing tips.

The last stage in assembling the TBS Caipirinha was to affix the wing tip stabilizers. There are two different types of stabilisers included in the kit, and the instruction manual explains the different flight characteristics of each. I chose to use the asymmetrical ‘bunny ear’ style wing tips as this is supposed to be better for HD video recording.

Included in the kit are two sets of self adhesive Velcro strips designed to affix the stabilisers to the wing. The instruction manual suggests using either hot-gluing or Velcro to fix the stabilisers in position. I decided to use hot-glue to permanently attach the stabilisers, as the Velcro pads did not provide the necessary stiffness to keep the stabilisers vertical during flight. A popular alternative method I have read about is to use two or three nylon stand-offs sunk in to the sides of the wing tips with circular servo horns used as plates to hold the stabiliser.

TBS Caipirinha 2s setup - total weight with GoPro 3.

Including the GoPro Hero 3 camera and lead ballast, the all-up-weight of the Caipirinha build came in at 641g, which was on target for the flying weight recommended in the instruction manual. To prepare for the maiden flight I bound the Delta-8 receiver to my radio transmitter and set up the elevon mixing as per the instructions. The instruction manual makes no mention of it, but all flying wings benefit from a small amount of reflex mixing on the elevons, so I added about 2mm while setting up the radio.

Flight Performance

My first few attempts at flying the Caipirinha did not end well. Hand launching a small wing which has no finger holes on the underside and winglets on the edges is difficult. Eventually I developed a way to launch the wing by holding the leading edge of the wing. Normally these minor setbacks are all part of the fun, but with my £350 GoPro attached to the nose, it was anything but that. In hindsight, I should have made a dead-weight equivalent for the GoPro to use during those initial setup flights.

Once in the air, it was immediately apparent that the wing was still tail heavy despite being correctly balanced on the centre of gravity declared in the manual. After an awkward landing, I added an extra 20g of lead weight under the front of the battery bay.

The following flight was more successful and I was able to start trimming the elevons while flying in first person view. I found that more elevator throw and less aileron throw was needed when using the instruction manual’s recommended throws as a starting point. Flying in near dead-calm conditions I was surprised at how twitchy and responsive the wing was, so I increased the elevon exponential value to about 50% to make smooth flying easier.

Starting to relax in to flying the Caipirinha, I now started to ease off the throttle, but at about 50% throttle the craft entered the infamous ‘flying wing death spiral’ and crashed. Thankfully the EPP foam is quite robust so the only damage was the winglets were knocked off in the crash. After removing the dried glue, I thought I’d try using the supplied self adhesive Velcro strips to reattach the winglets. This turned out to be a complete failure, with the winglets not staying vertical in the air and then falling off during the next flight.

At this point it was time to call it a day, and I left the flying field with two important lessons learned about this flying wing. First of all, the correct balancing of this aircraft is absolutely critical to successful flight. Secondly, I was having doubts about whether using 2S LiPo power is sufficient.

Over the following days and weeks I continued to fine tune the Caipirinha wing. I reattached the winglets with cyanoacrylate glue and spent a lot of time perfecting the balancing of the wing. I also replaced the Quanum 8x5 carbon fibre propeller with a Graupner 8x5 E-Prop propeller. After quite a lot of fine tuning the Caipirinha reached the point where it was flying properly and reliably. Flight times between 20 to 30 minutes were readily attained with my chosen 2S power system. Below is a video taken from the first successful flight with this Caipirinha - once set up, it flies beautifully:

Conclusion

Team BlackSheep advertise the Caipirinha as a beginner to expert level wing suitable for everyone. Personally I would say this is an intermediate to advanced model, simply because the small size and high wing loading make setting up and tuning this plane a challenge. That said, once properly setup, the Caipirinha is not particularly difficult to fly. Having flown this wing on 2S power for a while now, I’m planning to upgrade to 3S power soon and would certainly recommend any new Caipirinha builders to use 3S power from the outset.

Assembly of the wing was straightforward and easy, thanks to the pre-cut foam recesses and the high quality instruction manual. TBS really do deserve credit for producing such a comprehensive and well written manual. The factory laminated EPP foam has a good quality feel to it and is well finished. The inclusion of the foam ‘negative’ pieces was a good idea. Having balsa wood elevons that are covered in pre-shrunk film at the factory is also a quality feature.

The price of the Caipirinha kit is often cited on hobbyist forums as excessive, being compared to similar size flying wings such as the HobbyKing TekSumo. I think the price differential is justified however, given the various ‘value add’ features described above and the technical support available from TBS.

The only downside to this airframe is the way in which the winglets are attached. Using Velcro simply doesn’t work effectively, and probably shouldn’t even be offered as an option. Also, it would have been great to see some finger hole recesses on the underside of the wing, similar to the HobbyKing Ridge Ryder, to make hand launching easier.

Overall, the Team BlackSheep Caipirinha is a high quality flying wing kit with some great features. Once it has been trimmed out and balanced properly, it is great fun to fly. If you’re an intermediate to experienced pilot looking for a small FPV wing, the Caipirinha should definitely be on your short-list. If budget is a priority, the HobbyKing TekSumo might be worth a look. If storage and transportation are not a concern then a larger flying wing like the TBS ZII wing will be easier to set up.

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