Andrew Rabbitt
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  • Melbourne, Victoria
  • Australia
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Andrew Rabbitt's Discussions

Logging airspeed on 2.74 onwards...?

Started this discussion. Last reply by Andrew Rabbitt Feb 6. 2 Replies

Does anyone know which parameter group I can find airspeed to log (passively). I have looked in CTUN and NTUN but neither appear to have this listed. Any hints and tips here...?

APM in a 250

Started this discussion. Last reply by Rob_Lefebvre Jan 20. 8 Replies

The crazy man in me is trying to stuff an APM into a cheapie HK250GT as a method to waste an inordinate amount of time. (and likely also money) It is a great lesson in weight reduction and…Continue

Arduino/Ardupilot IDE "hangs" whilst attempting to complie

Started this discussion. Last reply by Andrew Rabbitt Aug 9, 2013. 1 Reply

I'm trying to compile a (very) subtly modified version of Arduplane 2.74b using the IDE downloaded from the Arduplane website (1.0.3) but it hangs when I try to compile.  Actually, it doesn't hang…Continue

Mapping servo neutral and end points...?

Started this discussion. Last reply by Andrew Rabbitt Aug 28, 2013. 5 Replies

Does anyone know any way of mapping the servo mid and end points that APM uses?I have modified elevons on my Skyfun which, unfortunately, have a limited down travel.  If the elevon servo forces it…Continue

 

Andrew Rabbitt's Page

Latest Activity

Andrew Rabbitt commented on Eric Compas's blog post APM response to catastrophic air frame/wing failure?
"Doug, it doesn't have to be very complicated to limit airframe load. It doesn't even have to be close to the ultimate load capability of the airframe. Just a programmable z acceleration limit would be sufficient to avoid cratering due to…"
Dec 7
Andrew Rabbitt commented on Eric Compas's blog post APM response to catastrophic air frame/wing failure?
"It would be easy enough to put in a throttle limit as a function of pitch angle. I think it'd be better if APM didn't let the airframe be overstressed in the first place"
Dec 7
Andrew Rabbitt commented on Jonatan Domenech's blog post Moving mass control
"For stability, you need to keep the centre of mass ahead of your neutral point.  If you start moving it around, chances are your stability will go to zero.  Your further research on aerodynamic stability will show you this. Also, in this…"
Dec 3
Andrew Rabbitt commented on Jonatan Domenech's blog post Moving mass control
"You need to do a little more research on aerodynamic pitch stability. You might be able to get roll control with a moving mass, but not (much) pitch. "
Dec 2
Andrew Rabbitt commented on Daniel Wibbing's blog post ObliX_neo: redesign of multirotor-blimp-drone
"You have no net centripetal force, Daniel.  The lateral forces that you show cancel each other out, although they do produce a yaw moment, but no net force to execute a turn. http://en.wikipedia.org/wiki/Free_body_diagram"
Dec 2
Andrew Rabbitt commented on Daniel Wibbing's blog post ObliX_neo: redesign of multirotor-blimp-drone
"I think you'll understand things better if you sit down and draw out a free body diagram for the system.  Start in two dimensions, keep your vector sign convention clear in your head, model your fins as (symmetric) aerofoils with flaps and…"
Dec 2
Andrew Rabbitt commented on Daniel Wibbing's blog post ObliX_neo: redesign of multirotor-blimp-drone
"Daniel, your bow and stern propellers aren't going to produce any significant centripetal force unless the aircraft is in a huge skid. Regarding passive stability, with fins fore and aft, you don't actually have any.  If you want…"
Dec 1
Andrew Rabbitt commented on Walter Volkmann's blog post World class small enterprise map production performance in Namibia.
"Nice work! Just as well it is APM1, since the US government thinks you'd be dangerous with anything faster!  Aren't you glad the authorities have your best interests at heart? ;)"
Dec 1
Andrew Rabbitt commented on Daniel Wibbing's blog post ObliX_neo: redesign of multirotor-blimp-drone
"Yes Daniel, it will probably yaw, but ask yourself where the centripetal force is going to come from if you (presumably) want to execute a turn (i.e. follow an arc) rather than just a yaw about the centre of gravity?  What happens in a slip or…"
Dec 1
Andrew Rabbitt commented on Daniel Wibbing's blog post ObliX_neo: redesign of multirotor-blimp-drone
"Interesting design Daniel. I think Petr is onto something with the number of motors, but also I think you have too many fins too.  The forward fins cancel out the effect of the rearward fins generating a net-zero pitch / yaw stability moment."
Nov 30
Andrew Rabbitt commented on Mario Carpeggiani's blog post A new wing design
"Except that in in Table 6, the Eppler 387 shows better data on all points at all Re.  That is a very confusing report and a 2D theoretical aerofoil is a long way from a physical 3D flying wing."
Nov 30
Andrew Rabbitt replied to Andrew Rabbitt's discussion Skyfun UAV build
"Daniel - at the end of the first post here is a .zip file filled with various .hex files to suit I used this database to figure out which one is suited to which ESC I used kkflashtool as well, but I remember it being a bit unfriendly."
Nov 26
Andrew Rabbitt commented on Mauricio's blog post Aeromapper 300 mapping drone –1.5 hr endurance with multisensor capabilities
"mP1, I think it's great to see what people are doing with open-source hardware and software.  Just because it starts as DIY doesn't mean it has to remain in that realm. You could argue (successfully) that 3DR's move to turn-key…"
Nov 26
Daniel Vukovich replied to Andrew Rabbitt's discussion Skyfun UAV build
"In the past I used kkflashtool to flash Simonk to my ESC's.  However, I can't find a hex file for the reversible version and I don't know how to set parameter RC_PULS_NEUTRAL. What application is required and how is the…"
Nov 26
Andrew Rabbitt commented on Mauricio's blog post Aeromapper 300 mapping drone –1.5 hr endurance with multisensor capabilities
"Oh, I see.   You reckon that, despite being unable to deliver the goods, you have such a good handle on the cost structure you could offer a similar or better product for several times less than that which is currently available. Yes, your…"
Nov 24
Andrew Rabbitt commented on Mauricio's blog post Aeromapper 300 mapping drone –1.5 hr endurance with multisensor capabilities
"Mike.  Please put your money where your mouth is and offer your version on the open market for USD2.5k.  Please also include operation and service manuals and factory support.  Oh, and please deliver the complete package by the end of…"
Nov 24

Profile Information

About Me:
Mechanical Engineer with more than a decade in electronic engine control development and application in the OEM sphere. I am a lapsed PPL(A) and currently an experimental aircraft builder (Van's RV-8). UAV's are a fascinating diversion from rivetting...
Please tell us a bit about your UAV interest
Inspired by press articles earlier this year on near-space ballooning, I would like to one day send a UAV glider aloft for a positionable return to land. I'm sure others have similar ideas.
Hometown:
Melbourne, Australia (sometimes)

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Andrew Rabbitt's Blog

Telemetry Radio Range testing with home-made dipole antenna

Posted on April 28, 2014 at 11:10pm 14 Comments

On Sunday I spent the morning self-consciously traipsing around my brother's neighborhood with an apparently wierd collection of hand-held electronics and foam in the form or my APM, battery and a Hextronic 3DR knock-off 915MHz telemetry radio and Skyfun fin. We left a laptop on the top floor of the house running APM Planner with the base station radio connected directly to the USB port and using a standard "duck" monopole…

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1300kJ/kg Battery - from the Too-Good-to-be-True Newsdesk

Posted on April 28, 2014 at 5:01pm 15 Comments

This smartphone-sized pocket battery is being marketed for emergency starting of cars with flattery-battery-syndrome, but if the manufacturers specs are believable it would make a fantastic power pack for quads etc.  More than…

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Mercedes Benz vision systems research

Posted on October 4, 2012 at 9:30am 4 Comments

I saw a feature about Mercedes-Benz collision avoidance vision systems research on the Telly here in Germany where I am at the moment. 

 

This particular project uses two cameras to create stereo vision.  Comparing the two images is used to detect pixels that represent motion that could be hazardous to the vehicles current path.

Unfortunately,…

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Mould Plug CNC Machining for HDwing4

Posted on May 24, 2012 at 10:03pm 5 Comments

Since the topic of CNC mills has raised its head here, I thought I'd share this with the DIYDrones community.

One of the things those who are considering this need to be aware of is that the toolpathing of complex shapes isn't a trivial exercise.  I would be interested to know if anyone has experience with any open-source surfacing toolpathing packages - please comment below! 

I am fortunate to have access to MasterCAM V9 - old-fashioned as it is - but…

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Comment Wall (3 comments)

At 6:15am on February 11, 2012, Paul Marsh said…

Oops.  Wrong URL in my PM to you.  Try this:

http://www.poweredmodelairplanes.com/outline.wrl

Paul

At 6:32am on June 17, 2013, Acorn said…

Andrew - Thank you for commenting on my BLOG DIY Passive Gimbal.

How about whacking four free-spinning electric motors on it? One flanking each axis? Just so it is balanced. Would they cancel eachother out? Or would making them spin CW / CCW to each other be better?

At 5:57pm on November 20, 2013, Justin Martin said…

Hello Andrew! Thanks for the support, and offer. I will definitely keep you in mind if anything comes up. The Idea behind the albatross is open. By this I mean, it has specific goals and design elements, however in the long run I would truly like innovations to be customer based. For instance, If customers started laser cutting their own internal storage shelves/formers, and/or other mods, such as a dome/nose adapter.

If the Pro version every comes to be, I will definitely be needing some specific arts, such as retaining clamps and rings for easy quick-release style components.

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