Comments

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  Stephen Gloor October 8, 2012 at 4:16am

  JB - "Biggest issue for FPV video and going the digital path is latency, but range and functionality, provided tracking and antenna selection is good is pretty hard to beat I think"

  The other one is legality.  ACMA defines most of the bands we use for a maximum power of 10mW unless of course you use digital.

  I am thinking of having a crack at the UAV Outback Challenge if they run one in 2014 and it all has to be completely legal for this.  We can get by transmitting video on 5.8G at 200mW however by the strict definition of the rules this is illegal.  Mind you so is flying out of sight however the MAAA does not really keep up.
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  John Cousins October 7, 2012 at 11:32am

  Nice! Some of what you just said went way over my head.. Software defined radio? Sounds like you are quite a bit above my level when it comes to RF knowledge.

  I like the idea of Mesh comms. Is your reasoning for multiple links to extend useful range (over the horizon) or is it just to have more aircraft in the air at once?

  As for going digital... it's a shame about the latency but it's fine for search and rescue.. not so good for seat of the pants flying is it?

  Looking forward to seeing what range can be sqeezed out of the Bullet M5s!

  I have a test I want to do, I want to find out what gives better range;

  1: Using a high gain linear polarised antenna on the aircraft coupled with a helical on the ground station

  or

  2: using a circularly polarised omni on the aircraft (typically low gain) and helical on the ground station.

  Will the higher gain of the linear omni offset the polarisation loss of linear to circular? that's what I want answered. I know high gain omni's aren't very good for FPV aerobatics, but UAVs tend to fly straight and level for long periods and perform shallow turns...

   

  Unfortunately for the Skywalker, she's already assembled and literally ready to fly. Looks like the tail will be shaking a bit then...

  I have the same problem as you re: c of g. I have a 5000mA 4S up front with a 1300maH above it for video. GoPro on the canopy,980kV motor and Chinese 5.8GHz Vid tx on the ususal platform out the back and it's could still use a little more weight on the nose. I still have heaps of space inside... but would probably be worse for c of g?

   

  Thanks for the offer of help, i'll keep you in the loop.
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  JB October 7, 2012 at 10:56am

  Thx John

  Sounds like a nice side business!

  Yes, I'm running a 915Mhz 3DR radio and would be happy to help do testing etc. I'm also running immersionRC 5.8Ghz video, and have also been looking at the possibility of using the Ubiqiuti for video/comms. Biggest issue for FPV video and going the digital path is latency, but range and functionality, provided tracking and antenna selection is good is pretty hard to beat I think. You can use OpenWRT for extra functionality. I'm also currently configuring the UAV notebook to run a RTL2836 as a SDR (software defined radio) as a tool to do a broad spectrum interference scan, and even possibly looking to implement a secondary comms reciever (it's only $20 a pop). I'm hoping to order a ettus SDR soon which will allow even better monitoring and tuning of the on board systems. At present I'm looking into the Hope RF transceiver for RC and comms ($10) which are also mesh compatible. They look pretty promising and are cheap. As stated previously on this thread I'd like to develop a flying environmental monitoring platform with integrated mesh comms. So everything radio is of interest to me as well. I'm leaning towards flying wings atm for ease of manufacturing, and endurance/range etc.

  BTW when building the Skywalker make sure to put some extra carbon spars into the rudder, it's fairly flimsy and vibrates a bit when under full throttle from the prop wash. My single wheel undercarriage is just two bits of rebated balsa with a carbon fibre axle, its simple and allows for easy glider like landings. The battery is also way forward to get CG 15mm in front of the servo wire, the 1500kV outrunner weighs about 115g and seems to have made it tail heavy. Running a battery in the under the wing compartment seems out of the question because of the CG constraints. I need 550g of battery and 115g of camera upfront to get there. I integrated a balsa shelf under CG for the APM. The wheel is mounted under the wing leading edge, and it tends to drop both main wing and tail at the same time after a 10-15m ground roll. The single wheel also shouldn't add much drag, as only one half is exposed out of the fuselage. Overall I'm happy with it, but now am looking for a wing...HobbyKing has just started selling the X8 I might try that next, or maybe a ZII...  

  Let me know how we can work together on this, I'm keen. 
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  John Cousins October 7, 2012 at 10:20am

  Nice work JB.

  I built myself a conventional undercarriage out of hand formed PVC. Heated and shaped complete with cross braces and foam wheels so I had a near RF transparent assembly (as I wanted to mount the skew planar under the fuselage). Definately looked the business... Just one problem. Didn't factor in the weight of the 5000mA battery.... FAIL... Put it in the plane and it shook badly. Oh well, back to the drawing board there.

  In other news.

  I've just started up a new business dealing with parts for UAS.

  To begin with it will just be telemetry, antennas and pug and play antenna trackers (for APM planner) but will expand as time and funds permit.

  I'm the first Australian importer of a new range of commercial grade circularly polarised antennas. Antennas are for;

  900 - 930 MHz (telemetry)

  4.9 - 5.9 GHz (telemetry (ubiquiti etc.) and IP video)

  5.7 - 5.9 GHz (analog video)

  Unfortunately they are VERY expensive but i'm hoping I can bring the price down over time. They come with full warranty support and VSWR report for each individual antenna. I'll be testing them when I get back to see whether I will order more. I could use some help there if your bird is flying well! I'm assuming you're using 915 - 928 MHz 3DR?

   

  

   
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  JB October 7, 2012 at 9:42am

  Hey John 

  Tell me about stale! Nothing for 6 weeks...I've been checking every 2-3 days but just wanted to see what would happen. Anyways John I have my 1880mm Skywalker already flying. Maidened it last week. Build was relatively straight forward, integrated a single landing wheel into the fuselage so that I can land it better on harder surfaces, like on the Safety Bay salt lakes. LEDs were a must also... Was actually there a few hours ago... was a bit gusty but the skywalker is much more stable than the comparatively twitchy bixler. It also doesn't care much about the weight, and with the battery in the nose it's no problem to fly in 20-35kmh wind...its fun landing it nearly vertically! 

  Let us know when and where you want to meet for a fly. I have the APM running with the old Skywalker params, and it seems to be fine. It still needs a bit of tweaking on the ailerons, they seem to react a little slow. But otherwise I'm pretty happy with it. 

  -

  Ootktk

  That's a bit sad... ;( I've had 2 lipo fires so far, both of which were related to my son's "mishandling" of them ie plugging two batteries into the same charge cable at the same time! It was burning on the garage workbench..we just heard these funny pop pop sounds, so luckily I checked otherwise the house might not be standing anymore!! The other time it was in his car, luckily I was around and quickly took it out, so the car was ok ($400 worth). Both instances have made me respectful of them, we now only charge in lipo bags, much safer if they can't torch something else.

  Anyway, same offer applies to you if you want to hang out flying, I'm willing to meet anywhere south of Perth, north can take over 90 minutes to get to for me. Let me know when and where.

  Would be good to catch up with anyone to trade ideas and have some fun flying.

  Regards

  JB
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  John Cousins October 7, 2012 at 9:34am

  @ootktk: Of course mate. I'll keep you in the loop. Bummer about the Raptor. Kinda gone off my Raptor since it's visit into the river :0( I found it flew too fast for my liking (even with the big wingspan) I haven't had any experience with elevons.. what airframe will you be flying? Need to learn a few things about mixing before I get the X8 airborne!
• ootktk October 7, 2012 at 8:07am

  mind if I come and learn how you tune your ardupilot? Just lost my fpvraptor and all electronics in a lipo fire so it's back to basics for me with some deltas wings again, pretty boring actually :(

   
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  John Cousins October 7, 2012 at 4:26am

  Evening all.

  Stuck out in the middle of the ocean at the moment but looks like i'll be getting home on the 17th of October. Who's up for some flying? I have a Skywalker to maiden and some Autopilot tuning to do. Where has everyone been lately? This group's gone a little stale again! Anyone got any news?
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  Stephen Gloor August 28, 2012 at 11:37pm

  Anyone seen this post?

  http://diydrones.com/group/apmusergroup/forum/topics/please-help-me...

  Which talks about the hardware manual switch that is lacking in the APM2.

  I am thinking of implementing it via the MUX that is mentioned in the replies.  Does anyone else have a hardware manual implemented?  
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  Stephen Gloor August 28, 2012 at 5:35am

  I started flying in the dim dark days when all I could possibly afford was a second hand two channel radio (Sanwa) and a Trident glider.  It had two sticks so thats how I flew when I graduated to more channels.

  I still have the radio.