Camera module for the Sine qua non (Runcam Thumb or Thumb Pro, forward looking)

This is a selection of camera pods for the Sine qua non that can be fitted to the fuselage in the mold of (and thus instead of) the back access cover, so they can arbitrarily be attached, detached, and exchanged in less than a minute.

The Runcam Thumb, at a weight of 10 g, and the Rumcam Thumb Pro, weighing 16 g, are ideal to be used as onboard cameras even on light airplane models like the Sine qua non. So what could be more obvious than designing a camera pod using these camera types? No sooner said than done, I made a whole range of pods right away. You can make your choice regarding three different aspects:

1. The type of camera to use (Runcam Thumb or Thumb Pro (W)).
2. The camera's angle (straight forward 0° or tilted upward by 4°)
3. The filament type to be used for printing (LW or regular)

Here you can see two example videos taken with these camera modules. The first one is taken using the Runcam Thumb, mounted on a 0° straight pod:

The second one is taken using the Runcam Thumb Pro W, mounted on a 4° angled pod:

Both videos are uncut and unedited, just as the cameras recorded them (yet it seems that Youtube added some compression artifacts to the original files, making it hard to judge image quality).

About the choice of camera models:
This is primarily a budget question… The Thumb, at a price of about $/€ 45, is a bargain, no question. The Thumb Pro (W) records at 4k resolution, offers more convenient features and can also be configured for FPV use (although this makes no sense with the Sine qua non), but surprisingly can't really outplay the Thumb in image quality if mounted on a winged plane (more about that in the videos' descriptions on Youtube). While it is still affordable in the US ($ 90), it is quite expensive in Europe (€ 125). 

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Note: None of these pods fit the Runcam Thumb 2 due to its differing power socket position. If you want to make a remix suitable for the Runcam Thumb 2, just drop me a note. I'll be glad to give you the Fusion360 file to work with.
Yet, if you have the choice, I'd encourage you to prefer the original Thumb or Thumb Pro model simply for weight reasons (the Thumb 2 weighs 27 g compared to 10 g (Thumb) or 16 g (Thumb Pro)).
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About the choice of camera angles:
Due to the Sine qua non being a pulling prop driven aircraft without a landing gear, the camera has to be positioned on top of the fuselage. Aditionally, I chose to mount the cam with a little offset to the back - firstly because this allows for using the module without CG compensation, and secondly because I did not want the propeller circle to be too prominent in the recorded image. But as a result the plane takes up nearly half the image if the camera aims straight forward in the flying direction. While this is fine for diagnostic purposes (if you, like me, take videos of your flights to improve your piloting skills by learning from your mistakes), it reduces the videos' aesthetic quality. So I made an extra version that tilts the camera up by 4° which is a good compromise of diagnostic and aesthetic quality. You can see the difference in the above example videos (the Thumb video is recorded using the straight pod, the Thumb Pro video with the angled pod).
I recommend to use the angled version unless you definitely need a camera angle that is perfectly parallel to the flight axis. If someone should request a version with a higher tilt angle, I can add that with little effort, so just feel free to comment.

About the choice of filament types:
Of course it makes sense to keep a plane model's payload as light as possible. Plus, ideally the payload should be placed in the model's CG, so it does not impact flying behaviour (In case of these camera modules, the CG is shifted less than 1 mm to the back, so no CG compensation is needed when changing from back access cover to camera module and vice versa).
So, to keep the construction as light as possible, I prefer LW (-PLA or -ASA) filament. But if the pod is to be printed using LW filament, it needs a little reinforcement compared to using regular (PLA, PETG, PA-CF, ABS, ASA…) filament. That's why there are different versions to choose from, depending on the filament type that's to be used.
Use the "LWfil" variants if you have LW filament available, and the “regular” if not. In my case, the LW variants (printed from LW-PLA) have a weight of about 5 g while the regular variants, printed from PA-CF, have about 8 g, so it's not such a big difference.
Note: Although I usually would not recommend to use LW-ASA for plane models, in this case it's ok to use since the physical stress the pod is exposed to is minimal.

So, to choose the cam pod you want to print:
The STL files are named following this scheme:
CamPod (camera model) (camera angle) (filament type).stl
Just choose the properties you want.

Printing

Import the pod(s) into your slicer and place them flat on the camera connection surface as shown in the image below.

Use the following parameters for slicing if using the LWfil versions:
- Vertical shells of one perimeter
- Extrusion width 0.6 mm
- 2–3% of gyroid infill at 1 mm infill anchor length
If using the regular versions, use an extrusion width of 0.5 mm instead. The rest of the settings is valid for both version types.

Aditionally, you will find a “Retainers.stl” file in the file set. The retainer holds the cam pod at the front end of the fuselage's slot. This part must not in any case be printed using LW filament since it has to withstand some force. Other than that, there are no special printing instructions for it.

Assembly

(Note: These instructions presume that you use a receiver with at least four servo channels at a voltage of roughly 5V. I'm not sure about the voltage range the Thumb cameras can cope with, but definitely they are not self-adjusting like the Runcam 2 which accepts up to 17V.) 

1. Crimp/solder/buy a cable that connects your camera to a servo port on your radio's receiver. Only the + and - pins need to be connected to the camera's 5V and GND pins, the signal pin is ignored. For crimping or soldering you can use the cable that is supplied with the camera (which, afaik, is the only chance to have correctly color coded cords since the cameras' pin usage is a little unusual).
   
2. Glue the retainer to the (straight) front edge of the pod's “back access cover dummy square” just like you would do with the original cover plate.
   
3. Plug the cable into your camera and push the servo plug through the pod's rectangular hole .
4. Use a double sided adhesive tape to connect the camera to the pod's front surface. I recommend using poster strips - these stick like hell but are easily removable. Please do not use velcro.
5. Softly pull the cable from the pod's underside and lay it into the channel on the upper side.
   That's it, you're done!

Operation

Just as simple as assembly:

1. Take the back access cover off the fuselage. With the receiver powered off, connect the servo plug to a free servo port (This is much more comfortable if you use an extension servo cord that stays connected to the receiver).
2. Slide the pod into the back fuselage's cavity so that it locks in place (make sure that the retainer holds the pod from inside the fuselage). Use the back access cover's screw to fix the pod in position.
3. Power on the receiver (of course, you should power on your transmitter first!). Now the camera's LED should light up. Depending on your camera settings, the camera will start recording right away or when the camera button is pushed.
4. The camera's USB port stays accessible even when the camera is mounted to the Sine qua non, so you just need to connect it if you want to transfer the video files to your computer. Of course, this is done more comfortably after taking the camera module off the plane.

What's next?

I plan on making a backward-looking camera module, too (nice to observe the rudder movements in flight) as well as further Sine qua non mods. If you want to be informed as soon as these will be available, just “follow” me (have to admit that I still have difficulties using that “following” vocabulary).

If you would like me to make a cam pod version with a higher tilt angle, just drop me a line in the comments. As said, this would be easy to do, but I will only make it if someone requests it.