Saturday, 2 March 2019

iNav Basics - Trim and Modes


IMPORTANT: Do not use any mixing, reduced rates, expo or trims in your transmitter.

The Flight Control Board handles all the mixing for you, including elevon mixing for wings and V-Tail mixing. All you need to do is program in 100% weight for each stick on Channels 1 to 4, and assign Mode switches to other channels.

My latest setup on the Taranis Q X7 (April 2019)

Ch1 100 Aileron
Ch2 100 Elevator
Ch3 100 Throttle
Ch4 100 Rudder
Ch5 Switch A (Arming)
Ch6 Switch B (Angle and Launch Assist)
Ch7 Switch C (Alt Hold with Cruise, and Alt Hold with Position Hold)
Ch8 Switch D (Manual and Return to Home)
Ch9 Switch F combined with S1 knob (Auto Trim and Auto Tune)
Ch9 Knob S1 changed to Flaps if Auto Trim and Tune no longer needed


IMPORTANT: Do not trim the plane using the transmitter trims

There are three types of trimming required for consistant behaviour across all modes

1. Trimming the control surfaces for level flight in Manual mode

First you must fly the plane in Manual mode and adjust the push rods (not the transmitter trims) for "hands off" level flight. iNav will ignore the transmitter trims in all Modes apart from Manual.

If your pushrods are not adjustable you can use the new iNav Auto Trim mode. See below for details.

2. Trimming the board alignment for level flight in Angle and Horizon modes

One of the most common problems with a new iNav installation is that the plane will lose altitude in Angle and Horizon modes. Don't be tempted to use the transmitter elevator trims to fix this behaviour.

Level flight in Angle or Horizon depends on the mounting alignment of the board. Most planes need some positive angle of attack or "nose up" to maintain altitude.

So it is usually necessary to add about +3 to +5 Pitch Degrees in the Configuration screen for the plane to maintain altitude in Angle / Horizon Mode. This depends on the plane and how you mount the board relative to the wing chord.

Angle and Horizon mode trim depends on board alignment (gyros and accelerometers)
Manual mode trim depends on control surfaces (Pushrods and servo angles)
GPS modes depend on GPS satellite information.

So you can see that switching out of a GPS mode may give nasty surprises if the control surfaces and board alignment are not quite right.

3. Auto Trim and Tune Modes

Auto Trim (for Manual Mode)
This mode attempts to adjust the servo mid points for level flight in Manual mode. Good for fine tuning trims once the pushrods have been adjusted correctly, or for fixed pushrods.

Pick a calm day, and while flying level in Manual mode, switch Auto Trim on.
The servo mid points over the first 2 seconds will be recorded.
If you are happy that the plane stayed level during those 2 seconds leave Auto Trim On and land the plane, disarm the board and the new trims will be saved.

Auto Tune (for Stabilised Modes)
This is another new mode that attempts to tune your PIFF values (Proportional, Integral and Feed Forward) for smooth stabilised flight with good control from stick inputs. iNav will learn how much control you need after analysing the reaction of the plane to your stick inputs.

Note: FF is the fixed wing replacement for D (Derivative). But it's still labelled as D in the iNav configurator PID screen.

Pick a calm day, launch and fly with no modes selected. The plane will be in Acro Mode (also called AIR) if no other modes are selected. Activate Auto Tune once you are flying comfortably.

Fly around giving full aileron stick movements left and right for at least 30sec, then repeat for the elevator, then the rudder. Initially the response will be very mild, but movement will increase as the test goes on.

Keep repeating the movements for a few minutes until the change in behaviour stabilises. Auto Tune records the new PIFF values every 5 seconds.

Turn Auto Tune OFF in the air, then land, let the plane sit for a few seconds then disarm.
The new PIFFs have not yet been permanently saved to the board. You need to Save with Stick Commands, or connect a Laptop and save using iNav Configurator.

Stick Commands
This is the simplest way to save the new PIFFs
While the board is disarmed, push the transmitter sticks full down and away from centre. The new settings will be saved.

The new PIFFs can be checked by opening the full OSD menu.

With the board disarmed, push the Throttle stick to the center, Rudder stick full left, and Elevator stick full up.

Note: Some users have trouble bringing up the OSD successfully. There are a few tricks to this.

Throttle, Rudder, Aileron and Elevator outputs must be active with full range and the board disarmed.

That means you can't have Throttle Cut or Channel Override activated (different to disarm), you must have a Rudder channel setup (even for flying wings) and you must ensure your stick movements give the full range output (1000 to 2000) in the iNav configurator Receiver page.

Full list of stick Commands. Arm and Disarm are deactivated if you use switch arming.

There are three types of Modes available in iNav.

Full control modes

Manual or Passthrough Mode
Normal flying with no stabilisation, only the Expo value in iNav is used. If something is going wrong with the FCB or GPS switch back to this mode to take control.

Acro or Air Mode
Slightly stabilised, holds the current orientation rather than self levelling, full control. Always active when no other mode is selected

Stabilisation modes 
These are Gyro and Accelerometer driven modes that rely on the board being level when the plane is in level flight attitude. Most planes fly level with the nose a few degrees up, so the board may need to be tilted down at the front, either in the mounting position or in iNav setup board alignment.

The Pitch Degrees required varies with different wings and different flying speeds. I usually start with +5º and adjust from there after test flights.

Angle mode
Fully stabilised, bank and pitch angles limited, will return to level. Can't do loops and rolls in this mode.

Horizon made
Starts off like Angle mode but allows greater control as the sticks are moved further.

Launch Assist Mode
This is a magic mode. Select Launch Assist, arm the board, advance the throttle to a good launch percentage (the motor will not spin up yet) throw the plane and the motor will spin up 0.5 sec after the throw acceleration is detected. The plane will climb for 5 sec then switch into any other mode you have selected, or until you move the sticks. I have used Launch Assist and RTL combined, so I can can launch and let the plane circle above without picking up the transmitter. A big crowd pleaser.

It's important to get the switch sequence right for Launch Assist to work.

GPS modes
These are GPS controlled modes, and they can be combined with the Stabilisation modes.

Altitude Hold
Does what it says, holds the flight path at the Altitude when selected. Very useful for level and stable flight paths.

Position Hold
The plane will circle around the point where the mode is selected, at the radius selected in iNav setup. Relies on a properly aligned FCB for altitude. Best to combine with Altitude Hold mode for a very useful Loiter mode.

Heading Hold
Uses rudder to hold the flight path to the heading when selected. Combine with Altitude hold for fixed heading and altitude flight path.

Return to Launch (RTL)
This is what it's all about. Enter this mode and the plane will fly back to where it was armed, at whatever altitude and throttle percentage you have setup in iNav, then circle overhead at the iNav setup altitude and radius (or even land automatically if you're game)

Failsafe RTL
For me this is the main reason for using iNav. Failsafe can be setup to go into RTL mode, meaning that if you lose radio contact with your plane it will fly back home.
On FrSKY X series receivers I set the failsafe to No Pulses, then in iNav - Failsafe RTL - Don't Land.

Here is the iNav Fixed Wing guide which will answer most questions - iNav FW Wiki
Here are all my iNav related videos on YouTube - iNav Playlist

Tuesday, 18 December 2018

3mm depron thermal glider

Now called the N3UTRON thanks to YouTuber Richard from 28th St. Air Land & Sea.
"why not go all the way? it’s the N3UTRON. its a subtle reference to Ed’s photon, the u glider 3 channel, and andrew’s last name"

Here are the dimension of a 3 channel motor glider made using 3mm and 6mm depron and a woven CF
arrow shaft.

Armin wing construction with 6 x 1mm CF strip spar.
HobbyKing contact glue and hot glue.
Document laminating film wing and tail covering. Scotch Tough tape fuselage covering.
Flying weight is 300g with a 950mAH 2S LiPo
Motor and 5 x 3" prop from the U-Glider
Spring / Pull control
2 x 13g metal geared servos
Wingspan 140cm.
Chord width 14cm.
Chord thickness 14mm

Build overview video

Flight video

Spring / Pull control example

Document laminate covering

Saturday, 1 September 2018

Action Camera Roundup

This page will evolve over time. Newly reviewed cameras with links will be added.

I frequently review Action Cameras on my YouTube Channel and am often asked for recommendations. This page will list all the cameras, with links and notes. I will update the list as I try more cameras in the future. Sensors and chipsets for each camera are listed where available.

I mostly use Action Cameras for recording product reviews, onboard footage and hatcam recording of RC Planes and recording scuba diving.

Generally I prefer lower contrast and lower saturated results, or at least have control over them, and prefer not to have a touch screen so I don't accidentally change settings. 

Check out my Action Camera Review Playlist on YouTube - PLAYLIST

Top Of The Range - GoPro competitors, true 4K
Price range A$290 to A$150 (US$220 to US$120)


Sony IMX377
Ambarella H22 S85
Top recommendation, this is the best quality action cam I have used. 4K 60fps and Gyro stabilised 4K 30fps. 2.33" touch screen. Good audio apart from too much noise cancelling in wind. External microphone and underwater housing available.
Review video
BANGGOOD purchase link

Xioami Mijia Mini
Sony IMX317
Ambarella A12
Bigger than all other action cams with a 2.4" touch screen. Superior quality video with image stabilisation at 1080P 60fps. No external mic unfortunately.

Sony IMX377
HiSilicon Hi3559V100
True 4k 30fps with stabilisation. 2.35" Touch screen. Blutooth remote. Sharp and saturated results but let down by significant colour fringing in the corners from the cheap lens. EIS works very well at 4k. 1080P not so good with poor sharpness unfortunately. 

GitUP F1
Sony IMX317 maybe
Ambarella A12
This is a superior quality flat-form 4k 30fps action camera. Has excellent image stabilisation at 1080 resolution and sparkling clear 4k recording. Would benefit from more subtle image adjustment options but otherwise it is amazing. Has PWM control which means it can be operated from your RC transmitter.
Review Video

True 4K Cameras based on 
Sony IMX117 sensor and Ambarella A12 chip
Price Range A$200 to A$120 (US$150 to US$90)

The cameras in this group are all very high quality with almost identical image quality. True 4K 30fps with EIS at 1080 60P. Smooth tonal gradations and natural colours. Audio can be muddy and slightly out of sync. Firmware updates may have improved this. All highly recommended. My current favourites are the Fireflys.


Firefly 8SE 170º Touch Screen
Best of the A12 chip Sony 117 sensor cameras. 
Improved audio quality and sync, comes with external microphone.
Superior video and photo quality. Can use touch screen and manual navigation buttons.
Available with 170º or 90º lens.
Review 1 Unboxing
Review 2 Results

Firefly 8S 170º 
Banggood 170º -

Firefly 8S 90º 
Banggood 90º -

Firefly External Microphone -
Gearbest 170º or 90º -

Foxeer Legend 3
Sony IMX117
Ambarella A12
Superior quality True 4K flat-form action cam with a very useful OLED screen. Very similar quality to all the other cameras using this chip and sensor

SJCAM SJ7 (Touch screen) 
Great quality video, touch screen, metal housing

ThiEYE T5e 
Same great quality video with no touch screen giving lighter weight, longer battery life

Eken V8s
Pan MN34110 14MP sensor
Ambarella A12 chip
This is a true 4k 25fps action cam with full time Electronic Image Stabilisation. Smooth and natural colours and decent audio with no sync problems. Not quite as sharp as the best but still very good.

Mid Range
Good performers, less expensive, usually not true 4k
Price Range A$180 to A$130 (US$140 to US$90)

The cameras in this range are usually not true 4K but capable of an interpolated 4k output. That means the lower resolution video is increased by the software. Video results are sharp but often too contrasty.


Panasonic MN34120PA 
Novatek NT96660 chip
Best quality mid range camera with rear touch screen and front info screen. Exactly the same size as the GoPro3 but 10g heavier at 82g. Gyro image stabilisation works very well. 

Firefly 8
Sony IMX117 sensor
Novatek NT96660 chip
Good mid range action cam if you like lots of contrast. It uses the high end Sony IMX117 sensor but matched with the lower spec Novatek 96660 chip. That means it cant do 4k 30fps but it does have good quality audio.
Review video

Sony IMX206 sensor
Novatek 96660 chip
This is the camera I use for the wide angle workbench views in all my reviews.
Much cheaper and better results than my GoPro 3+ Silver. Vibrant colours and sharp video and great still images too. Video Out for FPV, gyro image stabilization, 

Elephone REXSO Explorer K
Panasonic MN34120
HiSilicon HI3559
Good image quality but focussed closer than infinity, OK for close in action. Audio not great.

ThiEYE V5s
OmniVision OV4689 4MPx sensor
Allwinner chipset
A unique 4K 30fps action cam with UV and polarising filters included.
Build quality and accessories are excellent. Image quality is good but I had audio problems on my iMac and firmware upgrades are limited to PC.

Cameras based on 
Sony IMX078 sensor and Novatek 96660 chip

There are many cameras based on this combination of sensor and chip. They all have similar video quality which is very good for the price. Can be contrasty and over sharpened, with noticeable posterisation, pink banding and compression artefacts in areas of smooth blue sky. Better than the cheapest options.

SJ5000 Elite
Sony IMX078 sensor
Novatek 96660 chip
Another very good 2K 12Mpx action cam. Quite contrasty results.
Review video

Andoer AN5000 

Sony IMX078 sensor
Novatek 96660 chip
Comes with an excellent storage case, heaps of accessories and spoken mode settings.
The image quality is better than you would expect for the price of the camera. Video and stills are very sharp with contrasty and saturated colours. The down side is that the cheap lens produces a lot of colour fringing and occasional pink banding in blue sky.
Review video

Andoer AN300 flip screen
Sony IMX078 sensor
Novatek 96660 chip
Unique flip screen version of the AN5000 with the same image quality
Review video

Firefly 7S 90º lens
Sony IMX078 sensor
Novatek 96660 chip
Great if you want the narrower field of view. Less distortion than the full 170º fisheye cameras.
Review video

4K UHD Sports cam
Sony IMX078 sensor
Novatek 96660 chip
Very similar to all the above mid range cameras.

Onboard HD and FPV cameras.

Flat form, Splits and Cube

MOBIUS flat form cameras
Aptina AR0330 sensor
Novatek 96650 chip (possibly - according to
I love the Mobius cameras, simple cheap and great video results. Only 1080 30fps but the video looks better than most alternatives. Audio is Loud and there are lots of video adjustments available in the setup.
Beware when buying, there are many inferior fakes out there. The following links are verified sellers.

Mobius C2 is my most used onboard camera (widest FOV)
Mobius D for hatcam (narrower FOV)
Works very well with external microphone mod

Mobius Mini
Great little camera, 1080 60fps video, narrower 110º angle of view. Pefect for hatcam and onboard flight recording. Works for FPV as well. Useful for onboard smaller models that wouldn't handle the full sized Mobius with the added bonus of 60fps. WDR is not great, best for sunny days

Mobius Maxi
This is the big brother to the Mobius Mini, with an M12 lens available in 135º or 150º versions, bigger battery, Image stabilisation, G-Sensor image flip, Time-lapse photos, WiFi and PC setup apps (no Apple apps yet) and setup via FPV screen. 1080 60fps video gives the best image quality but it also does 2.7K 30fps and 4K 24fps. Audio is excellent but image quality is not up to the Mobius D and C2 versions unfortunately. Not as sharp or saturated, and anything above 1080P looks flat, grainy and blocky. Not really a good upgrade to the Mobius D and C2.
Review Video

Firefly  Q6 
Sony IMX078 sensor
Novatek 96660 chip
Very sharp video and stills, slight pinkish hue compared to Mobius, struggles with clear blue sky in some lighting and produces a pinkish band and blue fringing. Audio quality is very good, a little lower volume than Mobius. Gyro image stabilisation works well. Cheapest decent quality flat form action cam
Review video

Runcam 2
This is a popular 1080 60fps HD recording and FPV camera. FOV is not as wide as some action cams at 130º. Excellent image quality. Very low audio recording levels, good for onboard but not good for voice recording. Settings via smart phone app or FPV OSD. The big bonus is removable battery, and it's the same battery as the Runcam 3S.

Runcam 3S
Cheaper alternative to the discontinued GoPro Session. Video quality is a bit odd, with strange colours, purple fringing and extreme fisheye distortion. Limited to 1080 60fps, but that is a good resolution for most uses. Specifically designed for the mini quad market but it works well in the nose of a flying wing like the Sonic AR. Would be brilliant with a better quality lens and higher resolution.

Runcam Split
This is a unique FPV and HD recording camera designed specifically for mounting on a mini quad. The camera and processing recording board are separate and connected by a cable. RunCam Split is a split version of RunCam 3 for FPV. Supports recording 1080P 60fps and WDR. Built-in microphone, WiFi module.
HD recording looks great. SD card mount is poorly designed. 4:3 FPV view.

Runcam Split 2
Much better Runcam! This is the updated version of the Runcam Split and it's excellent. Wider input voltage - 2S to 4S, proper SD card slot, and can be operated by your transmitter via flight control board or PWM receiver. Slight vignetting and pink hue on one side, but looks good otherwise.  4:3 FPV view

Runcam Split Mini
Smaller and lighter version of the all in one HD recording and FPV camera.
Good quality 1080P 60fps HD recording. 4:3 FPV view

Foxeer Legend 1
Sony Exmor R BSI sensor
Ambarella A7LS Chip
Excellent image quality HD cam with 1080 60fps. Video-out for FPV and RC switchable shutter for video and stills. Audio is better than Runcam HD but not as clean as Mobius. Only configurable on PC (no Mac app at this stage)

Foxeer Legend 2 (now Legend 2+)
Sony Exmor R BSI sensor.
This is potentially a very nice HD cam (1080 60fps) with EIS, 4k 24fps probably interpolated. Using the stock settings the video and images are a bit too saturated and contrasty for my liking but there are lots of adjustments available through the smart phone app. The app needs improvement to make settings stick but otherwise it works well. Audio levels and quality are both better than most other similar cams apart from the Mobius.

Foxeer Legend 3
Sony IMX117
Ambarella A12
Superior quality True 4K flat-form action cam with a very useful OLED screen. Very similar quality to all the other cameras using this chip and sensor
Review Video
BANGGOOD Purchase Link
GEARBEST Purchase link

GitUP F1
Sony IMX317 maybe
Ambarella A12
This is the highest quality flat-form 4k 30fps action camera. Has excellent image stabilisation at 1080 resolution and sparkling clear 4k recording. Would benefit from more subtle image adjustment options but otherwise it is amazing. Has PWM control which means it can be operated from your RC transmitter.
Review Video

Budget Range - Less than A$100 (US$80)

Eken H9R
OmniVision OV4689 4MPx sensor
SPCA6350 chip
1080P sensor, has all the accessories including a remote control and waterproof housing, and performs surprisingly well for the money. No image stabilisation.
Review Video

ThiEYE i30+
PS5220 Sensor
SPCA 6330 Chip 
1080 30fps quality is OK. 4k 10fps is not worth using.
OK first action cam, or one for the kids, or for situations where you wouldn't want to risk an expensive camera. Results are usable but not high quality.
TOMTOP purchase link

4K 1080 sports cam
SONY IMX179 sensor
For the price the image quality is OK but there are some serious bugs. Sound recording is out of sync by about 1 second and movie files need to be converted to MOV for iMovie. Hopefully firmware updates will fix these issues.
Not recommended.