Hi there
Just a quick post of my Bixler v1.1 build and some mods I`ve done in the last weeks! The main goal was to fit in an APM 2.5 and a MinimOSD / Telemetry as well as the GPS, the FPV gear and all the standart RC gear "inside" the plane in an attempt to make this plane more aerodynamic. I didn`t see this setup so far, so I thought somebody might find it useful / has any suggestions.
The camera, the 5.8gHz TX and the MinimOSD are protected under the cockpit casing, which I have sprayed from the inside and attached with black tape on the canopy. The openings of the camera and the TX outlet allow enough air to pass trough, but make the hole cockpit area much more aerodynamical! (The TX could be mounted further down, but then there is no access to the channel switches anymore...).
The cockpit is secured using a 5x9x 60mm pice of wood glued on the cockpit and a rubber band around the fuselage.
Some pics:
The APM is mounted upside down between the two foam horns under the cockpit. I used some more rubber bands and some double sided tape.* See this post for additional informations: http://www.diydrones.com/profiles/blogs/mounting-an-apm-on-a-bixler2-upside-down-using-ahrs-orientation
The Servo cables and the Power wire is coming from the back of the plane along the battery all the way to the nose (30cm extension wires) and around the front of the plane. Almost everything is attached to this bunch of wires, the RC RX, the power filter etc. This way the cables stay where they belong, and the cockpit can be removed (to change the battery without worrying about the APM to much) and all the wires and attachments could still be easily taken out for repair/inspection/modification etc.
For the GPS (as soon as it arrives) I will cut a space just 5-8cm from the nose in the styro, insert the GPS and cover the section with tape.
Last but not least, the Radio module is stuffed way back besides the servos and behind the battery.
* I use "Plastik 70" on almost every board I own, http://www.conrad.at/ce/de/product/814169/CRC-Kontakt-Chemie-207436131201-PLASTIK-70-Hochisolierender-Schutzlack-400-ml for isolation and general protection. COVER THE BARO BEFORE SPRAYING!
Comments
here you go:
http://youtu.be/YSyhMDyrqwE
So, another update...
1. FPV Video proved to be difficult. In short, I was reminded why I dislike Easy Cap Hard-/Software.
2. I was busy testing some options how to actually mount all the stuff. This was the first "solution":
Not that great, but working. Next:
Tricky, but finally, I managed to get +/- 1mm close to the rounded canopy...
Closed, still some gaps == work to do...
Now, it looks much better. And as you can see, thanks to the rod and the structure its now possible to remove the canopy (like on the smaller plastic RC helicopters). It needs some more work and maybe some Velcro around the edges, but it will allow access to the electronics at all times. And yes, cardboard is only for testing, plywood will be much better...
Some remarks:
- How / should I move the hole thing to the forum since its more a discussion now?
- My original canopy & cockpit will be in pieces soon. Its annoying since I cant be sure if my measurements are really correct. So if anybody has some spare from a destroyed Bixler, I would really appreciate it :-)
- If somebody wants a dfx/pdf of the structure to EXPERIMENT (not perfect yet), send a message, thx.
sy
andreas
PS @Hugues
I found your CAT6 cable, but I it was to thick and stiff. There is no space in the canopy! (But it will be helpful for longer av wires or on a copter).
In the end I just wrapped the av video and the OSD and will test it that way first.
@martin
oh thats a big one!
Somehow the APC seems still to give more trust mounted backwards than the original prop mounted correctly ;-) Now, finally it has some thrust.
@Dennis
I would like to see some more informations on your build as well, since the payload is very limited in a bixler. The cog isn`t a big problem though, because I can move the battery 20cm and more from far back to the nose.
@John
As I said, I`ve flown a couple of times now. But today was the first sunny day, and the camera performance was just awful! So I will rebuild the cockpit with something else and document the build a bit better this time.
@Hugues
CAT6 cables are a great idea!
But instead of using an optocupler for the 5V UART lines, wouln`t it be easier to power the APM from a clean source in the first place? For example, using a power filter (as described below) / a 2nd battery (making sure the ground is really shared), and then feed from there video equipment and a BEC for the APM?
What do you use for the actual power supply of the video link? I used the same setup as on the copters: diode, 1500uF electrolytic & 100nF ceramic cap., but no solenoid. Works not to bad, but if you have any suggestions...?
@Swift
Coming soon!
I'm learning from this, thx!
In other posts and my own experience with MinimOSD, be aware that this little board generates extremely high radio frequency interferences in the 400-500 Mhz band => beware of the impact on for example 433Mhz.
What I've learned to avoid this is to use a CAT6 S/FTP network cable that if double shielded : a global shield and then a second shield around every pair of internal wires (you have 4 pairs in a CAT6 :gnd, video, audio, Vcc). So it is perfect for four particular video/audio/telemetry cables in your setup (because you do not have enough room to space your equipement apart):
-a telemetry cable from APM telemetry port to your telemetry air module (use five wires : gnd, 5v, Tx, Rx, CTS)
-a cable forking from the APM telemetry port to the telemetry input of MinimOSD (use three wires : gnd, 5v, APM Tx = MinimOSD Rx)
-a video cable from the camera to MinimOSD video input (use three wires : gnd, 12V, Video in)
-a video cable from the MinimOSD video Output to the Video transmitter input (use three wires : gnd, 12V, Video out)
DO NOT FORGET to solder the CAT6 shield to Ground on the source side only, that means:
-For the two cables between APM Telem port to MinimOSD and to Telemetry air module, solder the shield to ground on APM side (not on the other side otherwise you will create a ground loop)
-For the cable going from the camera to MinimOSD video IN, solder the shield to ground on the 12V source side.
-(same logic for the last cable from Video Tx to MinimOSD video out)
And after you have sprayed your minimOSD board with Plastik 70, you can wrap it with aluminium tape and link it to ground.
For refinements, you could also decouple the 5v feed from APM to the 5v power on the digital side of MinimOSD by using an optocoupler for ex. This will avoid that equipement (such as servos) that would be also fed by the 5V from APM would conduct power disturbances to your MinimOSD which is too sensitive about the least single disturbance (EMI or power).
As commented on an earlier blog post about a Bixler build, DIY Drones members may be interested in this page: Maker stories, reports, logs.
6x7 you have the prop fitted backwards in the first of your three photos showing your tape reinforcement.
If you look at your propeller from the side, the edges of the blades which are curved should face the direction in which the plane will travel, that is forwards, regardless of whether the plane is a pusher or a puller.
This also means that the writing giving the dimensions of the prop will also be facing the direction of travel.
We (the pilot and me (engineer)) have modified a Calypso glider with an APM 2.6 setup. Your installation looks a lot like ours but i think we might actually have slightly more room than you do. I like the "beam"/rubber band approach to keeping the now "heavy" cockpit lid in place - we have been taping but that is sort of crude compared to your approach. we are about to carry two gopros (one hero2 and one hero3) on our next flight - so far we have flown with just a hero3 and overall weight did not seem to be an issue. i suspect that we have an easier time keeping the cg in a usable location give the calypso configuration than you do with the pusher bixler. we have been carrying the fpv transmitter and wiring but haven't added the camera yet just due to time contraints and competing christmas season taskings from the wives. the calypso works great with the APM 2.6 and we are looking forward to upgrading to a Pixhawk sometime soon. thanks for sharing. dennis
Good call on attaching the canopy with a dowel and rubber band. Magnets are never strong enough and interfere with the magnetometer.
Hi Gary, now I see what you meant with the GPS, that was seperated from the weight.
Take off weight with GPS / rods and 2500mA 3S will be about 950gr. I have flown the plane a couple times yesterday and today and yes, it flies faster. But I found It more stable with the stiffened frame aw.
The carbon rod mod just ads about 100-150gr, the rest comes from the fpv / apm gear. So I would say it depends on your preferences... I'm used to multicopters and 800mm flying wing combat frames which are stalling in almost every kind of situation, so "bixler light" felt a bit boring actually :-)
But I agree, if you are a beginner / want a very slow, easy and stable plane use a bixler (and add fpv & apm later).
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