TransTEC Laser S - How to build a 6S FPV Racer

By Whiffles on May 31, 2019

41  5,422  42

A couple years ago I built the TransTEC Frog and since then I've been patiently waiting for another TransTEC frame to catch my eye. Fast forward to today and the TransTEC Laser S is that frame. It's a 82g racing frame that features 6mm arms, a TPU micro cam mount, 30.5mm and 20mm stack mounts and 3K carbon and 7075 hardware. My goal here was to build a high quality 6S racer at a reasonable price.

I'd like to thank XT-Xinte for sponsoring this build and keeping their prices low enough to make this so affordable. They're offering a $5 coupon for RotorBuilds users by following this link.

Alt Tag

Tools

This isn't a super challenging build, but it does require some fine soldering and an attention to detail. It's certainly doable as a first build, but keep in mind that you may find some pads frustrating to solder. With that being said here are the tools you'll need, and I've included direct links to the tools I use below.

  • Soldering iron
  • 1.5mm, 2.0mm, 2.5mm hex drivers
  • Industrial Tweezers
  • Wire cutter/stripper
  • Scissors
  • Heat gun or lighter
  • Ruler and cutting mat
  • Multimeter

Additional Supplies

  • A variety of heat shrink tube sizes
  • Blue Loctite
  • Zip ties (small)
  • 63/37 leaded solder
  • Liquid soldering flux pen

Hardware

You'll need to buy some additional hardware. The motors come with 6mm screws which are insufficient for the 6mm arms. You'll want to buy some 8mm screws to mount the motors. Regarding the stack, the red screws included in the kit don't give the 4-in-1 ESC enough clearance. I spent quite a while figuring out a solution and I ended up using 10mm screws and 8mm nylon standoffs to mount the stack. A better solution would be to use 18-20mm screws and an 8mm female-female standoff for better impact resistance. I linked some hardware options below.

It's also worth noting that my VTX came with an RP-SMA pigtail which doesn't match the antenna. I had to find an MMCX to SMA pigtail to use instead.

Frame Assembly

The frame doesn't have many parts, but you'll want to pay close attention to the instructions. The baseplate has holes for the rubber dampers, but only one side has an indentation. This side faces down. Try to put these in first before adding the arms. The thicker part of the rubber sits in the indentations. To get them in I found it best to squeeze them, push one end up through the hole and forcibly twist from the bottom until they pop through the top. Try not to push them through with a tool as you may poke a hole in them.

Also, make sure you orient the arms correctly. While you can't put the front arms in the back or vice versa you might accidentally mount them upside down. Make sure the curved ends of the arms face out toward the sides. Also, you may want to exclude the metal standoffs at this stage to give yourself space to solder, but get the arms in tight so they don't move around.

Alt TagAlt Tag

Motors

While it's optional I like to sleeve my motor wires with 1/4" Para-Max. It's also a great way to add a little color to your build. Keep in mind that the traditional 550 Paracord is too narrow for all 3 motor wires.

  1. Cut 4 pieces of cord (2x6cm & 2x7mm), remove the inner core and, with a lighter, melt the ends to prevent frays.
    • The rear motor wires have a little more ground to cover, thus the two different lengths.
  2. Sleeve the motor wires and add a couple pieces of 14mm shrink tube to cover the ends.
  3. Screw the motors onto the arms using 8mm M3 screws and blue Loctite.

Alt Tag

Now the order that you do the next few steps is very particular. You can't build the stack from the bottom to the top due to the clearances between the standoffs and the components on the boards.

  1. Remove the bottom standoffs from the Mamba stack and replace them with 8mm standoffs instead, keeping the small washers.
  2. Mount the stack on the red dampers and screw it in place with 10mm screws from below the frame. (Not too tight)
  3. Unplug and remove the flight controller leaving the standoffs on the 4-in-1 ESC.
  4. Flux and tin each motor pad ensuring each is completely coated with a bubble of solder.
  5. If you're right-handed start from the rightmost motor pad and solder all 6 wires from right to left.
    • If you're left handed start from the left.
    • Cut each wire to length as you go, not all at once.
    • Keep a flux pen handy because the middle pads are fairly close together and tend to bridge if you aren't careful.
  6. Position the shrink tube over the ends of the cord and melt it. You can use a heat gun to make quick work of this.

Alt Tag

Power Connector

The flight controller comes with everything you need: an XT60, wire and a capacitor.

  1. Solder the wires to the XT60 connector first and make sure you've got the polarity correct. Add shrink tube to cover the joints.
  2. Flux and add solder to the battery pads on the 4-in-1 ESC and solder the wires to the pads.
    • This requires a fair bit of heat and a good iron. Also be sure to re-tin the wires and add flux to help with heat dissipation.
  3. Solder the capacitor on top of the battery leads.
    • The striped side of the capacitor is negative.
    • The amount of wire you leave on the capacitor is crucial here. Depending on which antenna mount you decide to use it may get in the way. A little extra length won't hurt. You may also want to add shrink tube to the wires to insulate them. I used hot glue and covered the wires + capacitor with shrink tube.

Alt Tag

Binding the Receiver

Now that you've got power you can add the receiver and bind it. I used the FrSky XM+, but you'll need to choose a receiver that matches your radio.

  1. Solder 3 wires to the 5v, GND and SBUS pads on the receiver.
    • I borrowed some wire from the VTX. It's got enough to spare.
  2. Solder these wires to the 5v, GND and SBUS pads on the flight controller.
  3. Add your flight controller to the stack and re-connect it to the 4-in-1 ESC with the included wire harness.
  4. Bind your receiver
    • Be sure to double check that you don't have continuity between your main battery leads and use a smoke stopper if you have one.
    • Hold the bind button on the receiver while you plug the main battery in. (It's helpful to clamp this button down with tweezers to free your hand)
    • Put your radio into bind mode and make sure you're bound.
  5. Now that you're bound you can add some shrink tube to your receiver and tuck it under the flight controller.
  6. Attach small zip-ties to your front arms and shrink tube the antennas to the zip ties.
  7. Secure the flight controller with the included nylon nuts.

Alt Tag

Camera

This kit puts the camera very close to the flight controller, so you'll want to solder the wires before you mount the camera to the frame. I soldered the wires so they curve back and up toward the camera. You want a little slack so the camera angle can be freely adjusted. The wiring is very straightforward. Just solder the 5v, GND and Video wires to their respective pads directly adjacent to the camera.

Screw the camera into the TPU mount and slide the aluminum standoffs into the slots on both sides of the TPU mount. Now you can screw it onto the frame. Just make sure you don't pinch your receiver antennas!

Alt TagAlt Tag

Video Transmitter

Finally we need to add the VTX. This mounts directly above the flight controller, and you can use the standoffs you removed from below the 4-in-1 ESC to mount it. Before you do that, you'll need to solder the wires.

  1. Remove the extra GND and 5v output wires from the connector.
  2. Wire the VCC and GND wires to the large VCC and GND pads toward the rear of the flight controller.
  3. Wire the TX and Video wires to the pads directly adjacent to the USB connector.
  4. Mount the VTX and plug it in. Just don't forget the nylon nuts to hold it in place!

Now if you've got an SMA antenna like mine then you'll want to use the smaller TPU antenna mount.

  1. Using the 1.5mm hex screws and the nuts attach the mount to the top plate. Just make sure the countersunk holes are facing up.
  2. Strip the SMA connector down by removing the nut and washers and push it through the TPU mount. This might require a little force or even pliers.
  3. Route the SMA pigtail down under the power lead and back up to the VTX so the MMCX connector points down.
  4. Attach the top plate and screw on your antenna.

Alt Tag

Finishing Up

Now it's time to wrap it up! Here are a few extra steps to better secure your wires and components.

  • Zip-tie the main battery lead to the bottom plate using the provided holes. This helps reduce strain on the stack if the battery ejects.
  • Zip-tie the motor wires to the arms so they don't get snagged by a branch.
  • Add the provided battery pad to the underside of the quad.

Betaflight Configuration

If you don't already have them, you'll need to download Betaflight Configurator [Download] and the BLHeli Configurator [Download].

  1. First go to the Firmware Flasher and choose "FURYF4OSD" as well as the latest stable release of Betaflight.
  2. Click "Load Firmware [Online]" and then "Flash Firmware" to update your flight controller. Once complete, click "Connect"
  3. On the Ports tab
    • On UART1 click Serial RX for your receiver.
    • Set the UART3 Peripherals to "VTX (Tramp)".
    • Click Save and Reboot
  4. On the Configuration tab
    • Under ESC/Motor Features select DSHOT600
    • If want to fly "props out" with reversed motors, select "Motor direction is reversed" below the illustration. (This is optional)
    • Under System configuration set PID loop frequency to 8 kHz.
    • Under Receiver choose your receiver mode. For the XM+ choose "Serial-based receiver" and "SBUS"
    • Under Arming set the Max arm angle to 180 (Only if you keep the accelerometer turned on)
    • Under Other Features enable: Airmode, OSD, Anti Gravity and Dynamic Filter
    • Under DSHOT Beacon Configuration enable the beacon
    • Click Save and Reboot

To complete the remaining steps you'll need to apply lipo power to your build:

  1. On the Receiver tab ensure your pitch, roll, throttle and yaw are being applied correctly. Adjust your transmitter and Channel Map as needed.
  2. On the Modes tab
    • Assign an Aux switch to arm and disarm your quad.
    • Assign another Aux switch to enable Horizon or Angle mode if you need them.
    • Assign the Beeper and "Flip over after crash" to a 3rd and/or 4th switch. I like to assign them both to a single 3 point toggle switch.
  3. On the Motors tab enable the motor test and apply a small amount power to check the rotation of each motor. Take note of any that need to be reversed.
  4. Disconnect from the Betaflight Configurator and open BLHeli Configurator
    • Connect and Read Settings
    • Flash all ESCs to the latest firmware available.
    • Reverse the motor direction of any motors that need it. (The numbers correspond to the same numbers in Betaflight)
    • Save and reconnect to Betaflight Configurator to test the motor direction.
  5. On the OSD tab
    • Check all of the features you want and arrange your OSD as desired.

And that's it! The default Failsafe settings are generally fine, but make sure they work by arming your quad, applying a small amount of throttle and turning off your transmitter. It should shut down after a short moment.

Challenges

I didn't run into any technical challenges, but I had a hard time getting the stack spacing just right. The connector on the 4-in-1 ESC had to clear the front-most arm bracket. I needed exactly 8mm to make it happen. Any more would have caused the VTX to touch the top plate. I also struggled to solder the RX wires to the flight controller, but I eventually got them. I kept joining the pads with excess solder. Otherwise I accidentally screwed an arm in upside down and cut the rear sleeving too short. All-in-all it was a successful build!

Maiden Flight

When installing your props make sure to pay attention to the rotation direction illustrated on the Configuration tab in Betaflight. If you are flying "props in" then the leading edges of each prop needs to rotate toward the front and rear of the quad. If you are flying "props out" then the leading edges need to rotate toward the sides of the quad. Make sure the lock nuts are tight, but they don't need to be extremely tight. Conduct your first hover test in a safe place where you won't damage anything or hurt yourself.

Photos

Part List

Frame

TRANSTEC LASER S 224mm FPV Quadcopter Frame 6mm Arm 7075 Smooth Coating Carbon Fiber Frame For DALRC 55A 4 in 1 ESC 5Inch Props (3 builds)
Xt-xinte.com
$36.36

Flight Controller

DIATONE MAMBA F405 8K MINI POWER TOWER F405 Mini Betaflight Flight Controller F40 40A 3-6S DSHOT600 FPV Racing Brushless ESC for (55 builds)
Xt-xinte.com
$44.85

Motors

4 x IFlight Xing 2207 1700KV 1800KV 2450KV 2750KV 3-6S Motor FPV Racing Motor Super Light Engine for RC Racing Drone DIY Quadcopter (14 builds)
Xt-xinte.com
$71.96

Propellers

GEMFAN 2 Pairs Windancer 5043 PC Propeller 5 inch 3-blade Paddle CW CCW Props for FPV Drone Quadcopter Multicopter
Xt-xinte.com
$1.35

FPV Camera

Caddx Ratel 1/1.8'' Starlight HDR OSD 1200TVL NTSC/PAL 16:9/4:3 Switchable 1.66mm/2.1mm Lens FPV Camera For RC Drone Quadcopter (31 builds)
Xt-xinte.com
$31.99

FPV Transmitter

HGLRC Forward VTX 5.8G 48CH 25/50/100/200/400mW FPV Transmitter For RC Racing Drone Quadcopter
Xt-xinte.com
$17.81

Antenna

F4 V5PRO Flight Controller Spare Part MMCX to SMA / RP-SMA Antenna Pigtail Cable 10cm for RC Drone FPV Racing (3 builds)
Banggood.com
$2.16

Antenna

Pagoda 3 3B Antenna Omnidirectional Antenna for FPV Racing Drone 5.8G Image Transmission (3 builds)
Xt-xinte.com
$1.82

Receiver

Frsky XM+ Plus Micro D16 SBUS Full Range 2.4ghz Mini Receiver Up to 16CH for RC FPV Racing Drone w/ Double Antenna for Taranis X (1147 builds)
Xt-xinte.com
$13.86

Batteries

GNB 6S1P 1100mAh 6S 130C 22.2V XT60 Plug LiPo Battery For RC Drone (3 builds)
Banggood.com
$37.81

Radio

Jumper T16 Open Source Multi-protocol Radio Transmitter JumperTX 2.4G 16CH 4.3 inch LCD for FPV Racing Drone Aircraft (2 builds)
Xt-xinte.com
$149.00

Hardware

Suleve™ M3CH3 M3 Carbon Steel Allen Bolt 4-25mm Button Head Hex Socket Cap Screw Bolt Metric 240Pcs
Banggood.com
$5.99

Hardware

Suleve™ M3NH5 180Pcs M3 Nylon Screw Black Hex Screw Nut PCB Standoff Spacer Column Assortment Kit
Banggood.com
$3.66

Hardware

Suleve™ M3AR1 M3 Aluminum Alloy Standoff Studs 8-35mm Red Round PCB Board Spacers Standoffs 10pcs (5 builds)
Banggood.com
$2.81

Soldering Iron

Hakko FX888D-23BY Digital Soldering Station FX-888D FX-888 (blue & yellow) (12 builds)
Amazon.com
$99.42

Tools

XIAOMI Wowstick 1F+ 64 In 1 Electric Screwdriver Cordless Lithium-ion Charge LED Power Screwdriver (4 builds)
Banggood.com
$29.90

Misc Supplies

Kester 959T Soldering Flux Pen-Pak by TekLine 12ml No-Clean Low-Solids (2 builds)
Amazon.com
$7.40

Misc Supplies

328pcs 2:1 Polyolefin Heat Shrink Tubing 5 Color 8 Size Tube Sleeve Cable for RC Model (3 builds)
Banggood.com
$3.95

Misc Supplies

Kester 24-6337-8800 50 Activated Rosin Cored Wire Solder Roll, 245 No-Clean, 63/37 Alloy, 0.031" Diameter (5 builds)
Amazon.com
$25.09
Show stores (3)

Discussion

Sign in to comment

yahavz100   Jun 13, 2019  

Hey Whiffles, this is the 3rd FPV drone i'm planning to build, I have some rookie questions before ordering everything:
-Camera: order 1.66mm or 2.1mm? and what is ND filter? is it neccessery? searched some comments and someone recommended not to take the filter so it will fit right.
-F4 V5PRO MMCX to SMA / RP-SMA Antenna Pigtail Cable: buy RP-SMA or SMA?
-Pagoda 3B Antenna: buy RHCP or LHCP? inner hole or needle?
-Hardware: the screws you offered is sufficient for this build? I saw you wrote 18-20mm screws and I saw in those kits only 20mm is it enough?
Thanks for your help.

Show 16 more comments
Whiffles   Jul 17, 2019 

Great! Yeah that should do just fine.

yahavz100   4 days ago 

Its me again, finally the X8B arrived, do you know where I can connect the cable from the reciever to the FC? becuase its written at the FC sbus, and now I'm going to use ibus.
I found this but didn't understand the solution:
https://www.dronetrest.com/t/mamba-f405-flight-controller-wiring-to-frsky-r-xsr/7293

Whiffles   4 days ago 

Try RX1. That should be the ibus equivalent to the SBUS pad. You can get 5v and GND from the same place I did.

Mrkporky   27 days ago  

Really Kool drones. What kind of distance will travel and how long will they stay in the air

Whiffles   26 days ago 

Most racing quads will only fly 3-4 minutes, so you don't want to fly more than 1.5 minutes away. My rule of thumb is not to fly where I can't walk to retrieve it.

Mehul Shocker   Jun 29, 2019  

what would be the perfect prop for that motor? i was thinking azure 5150

Whiffles   Jun 29, 2019 

I think that's up to your personal preference. I generally fly Cyclone 5046C because I've been flying them for a while and I'm used to them.

Mehul Shocker   Jun 20, 2019  

so xt-xinte is a safe site to buy from?
how do they keep prices so low?

Whiffles   Jun 20, 2019 

Yes, they've been great to me. I think they just keep their costs down and they're comfortable working with thin margins. Also, they don't cook the shipping into the prices like Banggood does, so you need to factor that in.

Mehul Shocker   Jun 27, 2019 

sadly now the correct price is

JasonFPV0   Jun 11, 2019  

Had any mamba stack explosions on 6s yet? Today I had a motor unsolder itself when I hit a tree, but after resoldering the wire it worked fine, which surprised me.

Whiffles   Jun 12, 2019 

None yet, but I haven't put many packs through them quite yet.

PaulD   Jun 10, 2019  

Hey Whiffles, I was already considering a racing rig as my next build. I'm running 4S right now. Will this run well on 4S? If so, I might build it and practice on it using 4S, then step up to 6S when I gain the confidence. Thanks for another great build!

Whiffles   Jun 10, 2019 

Certainly! Just choose a higher kv rating on the motor. Anything from 2300kv to 2600kv is ideal for 4S.

BrandonSDeLaCruz   Jun 06, 2019  

wow very nice build. im about to get this same transtec laser frame but i think its not the S model. seems like a durable and reliable air frame. cant wait to fly it. thanks for the info and build review you supplyed.

Whiffles   Jun 06, 2019 

Thank you! I hope you enjoy the frame!

IcarusIX   May 31, 2019  

I felt like with some of the previous transtec frames, like the frog, you could fly absolutely fearlessly and you could really push them without worrying about the frame beaking, to what degree do you get that sense of security with this laser frame, or any kind of sleek modern race frame? its not like they're built super light either imo so idk. Ive had a few fragile frames but I dont tend to crash much, but I do love the thrash-abiliy of a chunky frame

Show 3 more comments
IcarusIX   Jun 01, 2019 
1

heres an example off rcgroups credit to gc_ober, 2206 motors, could easily stay under 200g dry with 2207 and fpv gear though still, its a very different craft to a durable reliable hit-taking racer (though light tube frames can be pretty durable when built light)

Quantum FPV   Jun 03, 2019 

As a frame designer myslef, I will say that while the FPV gear its self isn't too heavy, the accomidations for it that are required weigh a lot. In order to have room for a well protected FPV camera, you need to either lengthen the body and recess it, print a beefy TPU protector, or use carbon mounts that jut out a lot and make room on the frame for the carbon plates.

IcarusIX   Jun 04, 2019 

I agree a little bit but a simple bulletproof tower configuration on top can be made sub 15g easily for the entire fpv assembly incuding protection. heck, you could go down to about 4g with a nano cam like the caddx or runcam (so you dont stoop to aio quality) paired with a lightweight vtx if you dont care about protection. or strap an aio on, cos hey it works I guess.
(dude, you gotta try a tubular frame, get some cheap arrow chafts or 8mm carbon tubes and attack it with a dremel and epoxy, their handling's next level compared to typical frames :D ) (also apologies whiffles, deviating from the topic a bit)

daich   May 31, 2019  

awesome build! and for a spectacular price! thanks for that Xt-Xinte coupon too!

Mehul Shocker   May 31, 2019  
1

xing 50$!!?? how long will they be 55$ after sale ends?
and you should have sayed in he previous build that xing is available for 55$!!!

Guides & Reviews

21 1,541  11
3 days ago

Want to learn how to build an FPV rig? This guide will walk you through your first FPV freestyle build. These parts were hand-picked to balance cost and maximize performance. The TBS Source One is a popular frame for it's low cost, high quality carbon fiber. It's easy to work with and provides more than enough space for your electronics. We've got a 32bit 4-in-1 ESC to bring you the smoothest flights..

Read more
29 3,254  21
26 days ago

You've probably heard the term "Cinewhoop". Traditionally it's a 3" ducted quad capable of carrying a GoPro Hero7 Black at a low 10 degree angle. More recently the term "Cine" has been applied to a number of RTF quads ranging from 85mm to 3". They all focus on their HD capability, but none compare to the stabilization of Hypersmooth (only available on the Hero7 Black). This is what really offers that..

Read more