[Canberrauav] QuadPlane code ready to test

Brucebaxtersolutions brucebaxtersolutions at gmail.com
Mon Dec 28 16:10:42 AEDT 2015


With batteries go for the highest cell count.

Reasons,
The props must spin at a minimum rpm to keep the plane aloft, this is determined by minimum voltage.

The capacity (flying time) is the same watt hours no matter if it's 3 cell 4 amp hour or 4 cell 3 amp hour.

The speed controllers draw approximately the same power from the battery as is delivered to the motor, thereby acting as a "transformer" of sorts converting the higher volts into lower current and keeping the energy (volts X amp X hours) the same.

Net result?
The props can still provide excess lift at battery flat status, thereby avoiding the familiar problem of lack of stability and lift at battery flat status. 

Sent from my iPad

> On 28 Dec 2015, at 4:22 PM, Jack Pittar <jpittar at bigpond.net.au> wrote:
> 
> Further info: In reading my last post I realize I may have given the wrong
> impression regarding batteries.
> Approximately 80gm of lead was added to make the plane balance where I liked
> it to.
> I used that battery because they are close to what is required, and I have a
> number of them - not because it is the ideal battery.
> Without the lead, I could have used a 6200mAh Zippy compact 3S 40C battery
> at 451gm weight.
> I would prefer to some more flying before deciding if 3S is enough.
> My experience with batteries is limited, so I would leave it to more
> experienced fliers to advise what batteries are most appropriate.
> Jack.
> 
> -----Original Message-----
> From: Canberrauav [mailto:canberrauav-bounces at canberrauav.org.au]On
> Behalf Of Jack Pittar
> Sent: Sunday, 27 December 2015 7:38 PM
> To: Andrew Tridgell; SSUAV
> Cc: canberrauav at canberrauav.com
> Subject: Re: [Canberrauav] QuadPlane code ready to test
> 
> 
> That's good news Tridge.
> 
> Sacrificial quadplane status:
> 1. The Firstar has been flown manually with RC only using the Telemaster
> setup on the Taranis.
> 2. It has been painted for visability, white on top surface of wings,
> vertical stab and horizontal stab. I have some orange stick-on material for
> the wingtips.
> 3. The plane Pixhawk from the Vampire has been installed with external
> safety plug, USB connection, and switch. It balances with a 4Ah 3S 60C
> battery.
> 4. Right now I am working out how to program the CC Bec for 5.5 volts, prior
> to firing up and doing the calibrations.
> 5. I have collected all the bits and worked out how I will go about
> installing the quad components. I have decided to do it in virtually the
> same manner as the Vampire, except that the single battery in the fuselage
> will be used for both plane and quad.
> 
> I will be assembling the quad parts this week. Until they are ready, the
> aircraft will be able to flown as a plane. I would like to establish a set
> of parameters for it as an aircraft before converting it to the quadplane.
> Although officially this is the Vampire prototype 3, I think the name
> "Quadstar" would be more recognizable.
> 
> Jack.
> 
> 
> -----Original Message-----
> From: Andrew Tridgell [mailto:andrew at tridgell.net]
> Sent: Sunday, 27 December 2015 3:16 PM
> To: SSUAV
> Cc: jpittar at bigpond.net.au; canberrauav at canberrauav.com
> Subject: Re: [Canberrauav] QuadPlane code ready to test
> 
> 
>> Sounds great Tridge,
>> We would be keen to test drive your code.
> 
> ok, great, it's ready to test. Don't do the first flight on your most
> valuable plane though!
> 
> It is the same as plane master but with 3 extra modes:
> 
>    mode 17: QSTABILIZE (same as copter stabilize)
>    mode 18: QHOVER (same as copter alt_hold)
>    mode 19: QLOITER (same as copter loiter)
> 
> You'll need to set the FLTMODE* parameters as numeric values as your GCS
> won't understand these values yet.The code assumes a Quad-X frame, with
> the motors on outputs 5 to 8. The normal plane outputs are assumed to be
> on 1 to 4.
> 
> You can transition between any modes, fixed wing or quadplane. The
> transition rules are:
> 
> * if you transition to MANUAL then the quad motors will immediately stop
> 
> * if you transition to any other fixed wing mode then the quad will
>   continue to supply lift and stability in a hover until you reached
>   the ARSPD_FBW_MIN airspeed (or airspeed estimate if no airspeed
>   sensor)
> 
> * once that airspeed is reached the quad motors will slowly drop over
>   Q_TRANSITION_MS milliseconds (default is 5000, so 5 seconds)
> 
> You need to set Q_ENABLE to 1 to enable the QuadPlane functionality. All
> QuadPlane specific parameters start with Q_, so just set Q_* parameters
> as needed (they are very similar to the normal copter parameters). You
> should also set SCHED_LOOP_RATE to 400 so it runs the main loop at
> 400Hz.
> 
> You could also try the Q_ASSIST_SPEED parameter, which can be used to
> give quad assistance in any flight mode except MANUAL. Just set it to
> the airspeed below which you want assistance. You can use that to fly
> around at low speed in FBWA or CRUISE mode for example, or use it for
> assisted takeoff.
> 
> I've tested it in a simulator and it works nicely, but it has never been
> tried on a real aircraft. Let me know if you give it a go!
> 
> The code is here:
> 
>  https://github.com/tridge/ardupilot/tree/quadplane-wip
> 
> Cheers, Tridge
> 


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