More updates to the page

Thanks to all of you that have taken time to write to me via the contact page. I’ve tried to reply to them as soon as I have could. I also have received a bunch of encouraging e-mails.

I appreciate that a lot.
I apparently have a lot of fans. I received a couple of e-mails asking if it is possible to donate funds to support this homepage. Wow, I never thought people wanted to give away money to help me feed my RC-addiction. I must be doing something right! This is why I added a donate page to the sidebar.

I killed my FPV FunJet

Oops I did it again. I killed another airplane. This time it was my FPV FunJet that didn’t make it.

There were no wind, and the sun was shining. I just had to get outside and fly some FPV. I had equipped the FunJet with the Aiptek Z500 and this was supposed to be the first flight with it. I gave full throttle and chucked the FunJet into the sky. I love the way the FunJet fly, especially when it’s dead calm. After a while in the air, I noticed a tree line 300 metes long and only 3 or 4 trees thick. I couldn’t resist. I started to fly through the gaps in the trees. It was so much fun. On the way back I flew so low that the prop hit the loose snow. I went back for 3 or 4 turns before I did something stupid. I saw a bigger gap in the trees where a road crossed the tree line. I decided fly at full throttle through the gap and then follow the tree line all the way around. But when I got to the gap and started to turn I lost video signal for one second. And it was all it took. When I got the picture back I saw a big branch in the middle of the picture and then it went black again. I heard a loud sound like a whip crack and knew that this was the end of the FunJet.

I started walking the kilometer in deep snow. The pieces were scattered everywhere. I didn’t even manage to find some of them. The ESC lay totally disconnected 10 meters away and the motor lay nearly 50 meters from the tree! This crash had some force to it. Luckily all the electronics works fine, even the camera. It’s just the airframe that’s needs replacing. I ordered a new one and I hope the next FPV FunJet will take up the mantel and do an even better job than it’s admirable predecessor.

Unfortunately the camera was disconnected in the crash which resulted in a corrupt video. I’ve been trying like mad to get it to work but without success. Anyone happen to be an expert in video recovery by any chance?

Teaching others about FPV

esterday I was invited to a local club to talk about FPV. It was Falköpings model flight club, Blue Max, that had requested me to show my FPV gear, my videos and talk a bit about FPV in general.

It was nice to meet people sharing my interests and they really seemed eager to hear what I had to say. I gave a presentation for about one and a half hour and then we mingled another hour away. They showed me a bunch of slope-soaring models and I kind of want to try that now… In Falköping, there is a great place for slope-soaring called Ålleberg and they showed me videos from there. When winter finally lets go I just might make a visit there.

For those of you that understand Swedish, they wrote about the visit on their homepage.


The Tricopter V1 and V1.5

It was a long time since I owned a helicopter, they were to expensive and fragile. I hated that you had to order replacement parts every time you had a minor crash. I want to be able to repair it my self, swift and easy. So I decided to design my self a Tricopter. That way I get it just the way I want it.

Be sure to check out the Tricopter V2 and V2.5 builds as well!

So what is a Tricopter?

It’s an aircraft similar to a helicopter except it has three rotor disks. The beauty of the design is that three ordinary outrunners direct driving ordinary propellers can be used. Four helicopter gyros makes the tricopter super stable. And to make it yaw a servo tilts the back motor. You set your radio for 120° CCPM and your good to go. It’s as simple as that. Very low part count, simple, cheap, easy to build with no advanced electronics needed.
Read my guide on how to set our own tricopter up.

What to buy?
After testing various speed controllers, motors, gyros, etc. These are the electronics I recommend buying for a tricopter weighing under 1.2kg:
3 x 2213N 800Kv Brushless motors
3 x TURNIGY Plush 18amp Speed Controllers
4 x Hobby King 401B AVCS Digital Head Lock Gyro
1 x 6 pack GWS 10*4.7 propellers
1 x 10 pack prop adapters
1 x BMS-385DMAX Digital Servo (Metal Gear)

1 x 3S 2200mAh Turnigy LiPo
1 x Turnigy UBEC for making the “jump starter” for the gyros

These are electronics I know work good on a Tricopter and have personally tested.

The Build
Now lets start building.

I used 1.5mm DIY PCB glass fiber laminate for making the motor mounts.

This is my solution for the back motor tilt. It’s a T-Rex 450 blade grip mounted to a piece of plastic.

It’s super low friction that I hope will give me a slop free tilt mechanism.

The back motor mount test fitted with the tilt mechanism.

I used a T-Rex 450 tailboom that I had laying around for making a light weight filler so that the glass fiber lamination doesn’t flex when I screw down the motor.

I made a simple servo mount to get the servo to the right height and make it easy to remove.

Here are the servo plates that also holds the tilt mechanism.

To remove weight I etched away the copper from the glass fibre laminates.

Test fitting the motor mount.

Turned out pretty nice. I will be using wood as my arms and as you can see in the picture, the mount is just screwed down, clamping the wood. This makes it super easy to fit new arms if I ever brake one or want to try longer ones.

This is my frame design. It’s not super pretty but I hope it does the job.

My tricopter is going to be foldable so I drilled a hole through the two front arms.

The tilt mechanism almost done. I had to add a piece of plastic to make it as thick as the arms.

Tilt mechanism done.

Motor mounts done.

I cut of a piece of the top piece of the frame to be able to mount the receiver in-between the to sheets of 1.5mm glass fiber laminate.

Gyros in place.

Started work on extending the cables on all the ESCs. Before and after.

All the electronics in place.

For some reason the Turnigy gyros did not work well with the Futaba receiver I had planned on using. I think it has something to do with the shorter frame rate Futaba 2.4GHz system uses. It made the output of the gyros go crazy at some points, so now I use a Assan 6 channel receiver.

Tilt mechanism cable solution.

Underside of the frame.

The arms when the tricopter is folded for transport.

The frame when it’s folded for transport.

Time for a test flight!

It flies!


The canopy and landing gear are from an old T-Rex 450. I simply trimmed it a bit and painted it orange.

I think it turned out pretty good, if I may say so my self.

Now it is time to take it to the indoor event!

This is the premiere flight from the indoor event;

It’s a joy to fly! So stable and forgiving. I think it will make a great FPV platform.

Specs of the Tricopter:
Motors: 2213N 800Kv AXN
ESC’s: Supersimple 18A Card Programmable
Battery: 3s Turnigy 25-35C 2200mAh LiPo
Servo: Power HD 2216MG Digital
Props: GWS 1047
Power: [email protected] – 6370RPM – 780 grams thrust / motor!
Size: 40cm radius (center to motoraxel)
All up weight: 777 grams
Flight time: 15 minutes
Current draw during hover: ~8A

Because you asked for it, here is the PDF template of the center and motor plates:
Click on the picture or here to download
Be sure to set the page scaling to 100% when printing.

Due to popular demand I now offer pre-cut V1 tricopter frames!

Do you want to build your own Tricopter but don’t know how to set it up? Read this guide and you will find the answers.

First FPV video from the Tricopter:


RC TX: Futaba 7C FASST 2.4GHz
Camera: 1/3” Sony CCD camera (more info)
Video TX: 1.3GHz 300mW, 1/4 Lambda antenna
Video RX: 1.3GHz dual output
Video RX antenna: Stock whip
OSD: Flytron SimpleOSD XL + GPS
Video capturing unit: Sandisk V-Mate

Tricopter V1.5

Since the Trunigy 302 gyros doesn’t work well with my Futaba FASST receiver I decided to try using 4 Hobbyking HK401B gyros instead.
I noticed on the old 401 gyro I had that the PCB inside of the case wasn’t secured properly so before mounting the 4 new gyros I took them apart and secured them a little better.Here is how to do it;

Unscrew the 4 bottom screws and lift out the PCB.

If you want to be absolute sure that the cables aren’t stressed and break in a crash, use a bit of hot glue to secure them to the PCB.

To secure the PCB inside of the case use a small drop of hot glue in each corner of the case and while it’s still hot place the PCB in the case and push it down until it’s fixated.

To make absolute sure that the PCB will remain fixed I used an extra piece of foam between the lid and the PCB. Now screw the case together and you’re done.

Since the HK401 gyros have a bigger footprint I needed a slightly bigger frame. But instead of making a totally new one I simply made a modified top plate.

Futaba FASST receiver mounted.

All done!

One thing I noticed right away with the new gyros is that do not arm the ESC’s. This is because they do not give a valid signal during the start up initialization, this makes the ECS’s think that you have an FM receiver without a valid signal and the ESC’s goes into protective mode. Which is to say they will not initialize until they are restarted and get a valid signal. But if I was to restart the ESC’s the gyros will reboot as well since I’m using the built in BEC’s of the ESC’s and were back to square one again. To solve this problem I made an external BEC to “jump start” the receiver and gyros;

When I plug this external BEC (with a diode in series with the possessive output, just to be sure) into a free channel on the receiver and then connect it to the balance connector on the battery, the BEC will only power the receiver and gyros. After the gyros have initialized I plug in the main battery connector, powering up the ESC’s. Now the ESC’s get a valid signal and boots up just fine. I then remove the external BEC that I used to “jump start” and can now enjoy my flight.

Time to fly!

It flies!
Comparing the old Turnigy 302 gyros to the new HK401B, the HK401B’s are much more sensitive to vibrations. But once you get rid of the vibrations the HK401B’s perform a little better than the 302’s. It feels a more locked in and even more stable. The HK401B’s also work in digital mode, unlike the 302’s that made the whole tricopter jerk horrible in mid air at random times. But the best part is that they work great with my FASST receiver. I’m happy that I tried the HK401B’s.

First HD FPV video from the GoPro Hero HD;

RC TX: Futaba 7C FASST 2.4GHz
Camera: GoPro Hero HD set at 720p 60FPS
Video TX: 1.3GHz 300mW, 1/4 Lambda antenna
Video RX: 1.3GHz with modified SAW filter
Video RX antenna: Stock whip

Because you asked for it, here is the PDF template of the center plates:
Click on the picture or here to download
Be sure to set the page scaling to 100% when printing.

I’m mentioned on the ATTF and InsideHeli Podcasts!

I was sitting at work, doing a monotone task and listening to the newest episode of All things that fly, when I suddenly heard my homepage being mentioned on the show. They had found my Tricopter build and thought it was awesome. They spent 5 minutes talking about the build and tricopters in general.

You can download and listen to the episode here; ATTF #133.mp3
They start talking about the Tricopter about 36 minutes in to the show.

I always listen to ATTF first then InsideHeli and to my great surprice this weeks episode was named “Lipo Fire and TriCopters”
32 minutes in to the episode they start to talk about my build!
Chris thinks it looks like a scorpion and now wants to build one himself. They spent over 12 minutes talking about the build and tricopters in general.

You can download and listen to the episode here; InsideHeli #84.mp3

A big thanks to Diggs, Jamie, Chris and James for doing the shows. I always look forward to tuesdays, because that’s ATTF day.


Tricopter V1 and V1.5 setup guide

A lot of people have asked me to make a guide on how everything is connected and the setup, so here it is.

The tricopter is controlled in the exact same way as a 120° CCPM swashplate on a normal helicopter. Which is to say that when you want the tricopter to go forward (elevator) the two front motors slows down and the back one speeds up, when you want it to go right (aileron) the left motor speeds up and the right one slows down and vice versa. This means that you connect the three speedcontollers just like you would the three servos on a 120° swashplate. On my Futaba setup that means left motor channel 1, back motor channel 2 and right motor channel 6 (looking at the tricopter from the back, tail facing you).

If you were to try to fly a tricoper without gyros you would probably crash straight away. This is because every motor has little different kV and the ESC’s aren’t perfectly matched. This means that every motor will react a little differently to throttle input and not spin up to the exact same RPM. Even if you got it trimmed out perfectly, a tricoper isn’t a self stabilizing aircraft. It doesn’t want to stay nice and level. It wants to crash. It would be quite a handful simply to keep it in a hover, especially if there was a breeze outside. This is why a gyro on each motor is used, to make it stable and easy to fly.

A gyro is made to counter any acceleration on the axis that sensor is measuring. So if a force (like the wind) tries to tilt the left arm of the tricopter upwards, the gyro on that arm makes the motor slow down enough to prevent the arm from accelerating upwards. Each of the gyros have no idea of the other gyros on the tricopter and only keep tack of their own motor. This is why the gyros needs to be mounted in the same angle as the arms which holds the motors, so they compensate on the right axis.

The gyros that control the motors must be in rate mode. If heading hold mode is used the gyros will try and fight each other, inevitable ending in a crash. The easiest way to tell if a gyro is in heading hold or rate mode is to connect a servo and see if it creeps in any direction. Another test is to move the gyro to see if the servo moves to its max position and if it returns to neutral or not when you stop moving the gyro. If it’s in rate mode the servo only moves when you move the gyro and returns to center when you stop moving the gyro, so if it creeps or doesn’t return to neutral you should change the mode (which is done by inverting the gain).

The tail (yaw) of the tricopter is controlled by tilting the back motor to the left or right.

This is done by a servo just like on a normal helicopter, and just like on a normal helicopter a gyro is used on this axis as well. This brings the total of gyros on a tricopter to four. This gyro can be used in either rate or heading hold mode, depending on which you prefer. (If you don’t know which one you prefer, I recommend using heading hold.) Thanks to the other three gyros, the tricopter remains perfectly level when the tail rotor is tilted and the tricopter rotates around its own axel.

Hooking everything up
This is a diagram showing how everything is connected on a tricopter (click for a larger picture):

The three main gyros are connected in series with the ESCs and the three gyro gain wires are connected together in parallel to the same channel, in my case channel 3. This means that the three main gyros have the same gyro sensitivity. The tail servo is connected in series with the tail gyro and the gain wire is connected to channel 5 which is the gyro gain channel on my Futaba system. This way I can change both the gain on the tail gyro and the three main gyros separately directly in the transmitter.

Transmitter settings

Observe! For the following example, you will need three servos of your choice (whatever you have lying around). These servos will not be needed any more once the setup is done.

Now it is time to program your radio. I use a Futaba 7C so that’s what I’ll be using as a reference. Start of by switching to helicopter mode and set the swashplate setting to 120° CCPM (HR3). Before you start, you should test one speed controller connected to channel 3, to make sure that you have the throttle settings the right way and not reversed. Then plug in a servo and watch to which endpoint it goes to. This is so you know which way the servo moves when more throttle is applied. Now you can use three servos instead of the speed controllers to set things up, as it’s much easier to see exactly what’s happening and much less risk of getting hurt. Hook up the three servos to channel 1,2 and 6 without the gyros. At this stage all we want to know is that the swash settings are correct, no need to add variables to mess things up. Go into the swash menu and change the settings to Aileron +40, Elevator +40 and Pitch +100.

Move the throttle stick upwards, all three servos should be moving up. If they don’t, go into the reverse menu and reverse the channel that’s moving the wrong way. Try again. When all the servos move up when you increase throttle your can proceed to the next step. If all servos move the wrong way change the Pitch setting in the swash menu to -100 instead of +100.

Move the throttle stick to around the middle and leave it there. Then move the aileron stick (left stick) to the right, the servo connected to channel 6 should move down, indicating less throttle, and the servo connected to channel 1 should move up, indicating more throttle. If it’s reversed go into the swash menu and change the Aileron setting to -40 instead of +40. Try again. It should be moving the right way now. The servo connected to channel 2 should not move at all.

Move the elevator stick (left stick) forward, the servo connected to channel 2 should move up (more throttle) and the channel 1 and 6 servos should move down (less throttle). If it’s reversed change the Elevator settings to -40 instead of +40.

These are the settings I ended up with:
No reversed servos
Swash Ail +40, ELE -40, PIT +100

Time to set up the three main gyros. Connect the them in series with the servos and connect the three gyro gain wires to channel 3. It will make things much easier if you have the gyros placed on the frame at this stage. Set your throttle curve to 0% and move a gyro to check if it’s in heading hold mode. If it is in heading hold mode, set the throttle curve to 100% instead to switch the gyros to rate mode instead. Now tip the frame in the same direction as one of the arms and keep an eye at the servo connected to that arm. When you tip the arm downwards the servo should be moving up (more throttle) to compensate. If it doesn’t you need to change the little dip switch on the gyro called servo direction, reversed or something similar. Try again to make sure that it moves in the right direction. Repeat this with the other two arms.

Check that the tail servo is moving the right way when you move the rudder stick. If it doesn’t reverse channel 4 in the radio. Set the gyro gain (channel 5) to 0% and check if the gyro is in heading hold mode, if it’s not set the gain to 100% instead. Check that the gyro compensates in the right direction by swinging the tail one direction, the servo should give throw in the opposite direction. If it doesn’t reverse the direction switch on the gyro.

You’re almost done now. Set all the point on the throttle curve to 30% (70% if you had to invert channel 3 to get the gyros into rate mode). This is a good starting point for your first jump with the tricopter.

Set the gyro setting on the tail to 20% (or 80% if channel 5 inverted to get it into heading hold mode).

Complete your build and hook everything up according to the diagram above. Be sure to double check everything. Every time you start your tricopter you have to recalibrate the throttle endpoints on your speed controllers. This is to make sure that they all have the exact same endpoints. So to start up your tricopter first power up the transmitter and reset all the trims, then move the throttle stick to the max position (full throttle). Plug in the battery in the tricopter and wait for the gyros to initialize. Wait for the ESCs to sound their beep for entering throttle calibration and then move the throttle stick to the down position. The ESCs should play a little tune indicating that they are ready.

Time to test fly!
Find a pretty big open space without any wind. The first flight will be dedicated to setting the gyro gain. Take of and get it above the ground effect (0.5 meters or so). If it doesn’t wobble or oscillate, land it and increase the gain of the main gyros by 2% (e g to 28% if you had 30% before). Try it again and repeat until you start to get a faint oscillation (the gyros overcompensating), land it and lower the gain by 1% and your done! Now it’s as stable as it can be. Do the same thing with the tail gyro, but don’t be surprised if you get to 100% without oscillation.

My current gain settings: Throttle curve 14.5% (main gyros), Gyro gain 11% (tail).

If you feel that the tricopter is too sensitive around mid-stick you can add some expo, lower the rates or lower the aileron and elevator swash settings. I like my tricopter at 40% aileron and elevator settings with no expo and 100% at all rates, but to each his own.

Good luck and fly safe.