Proxima II ! My most complex UDB4 plane. A tribute to Bill Premerlani - RC Groups
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Mar 03, 2012, 10:19 AM to put on air 100 models
chiloschista's Avatar

Proxima II ! My most complex UDB4 plane. A tribute to Bill Premerlani

Hi all,

after a lot of research, programming, setting and tuning, I'm proud to announce that my Proxima II went in flight.

It was already, but without any autopilot, only to set the right controls, trims, CG and wings angle of attack.

Now it is fully autonomous. This is the more complex autopilot equipped plane I ever build.
Here you can see the plane in full action.

Proxima II ! (3 min 20 sec)

In this video there is a demonstration of the controls possibilities.

Proxima II functions (4 min 1 sec)

The pilot has the following controls over the plane :
  • throttle
  • elevator
  • rudder
  • ailerons, differential !
  • flaps, with those functions : thermal flaps, crow flaps
  • autopilot mode
  • coming next will be camera pan / tilt and camera mode controls

Possibilities are :
  • roll control over two (ailerons) or four surfaces (ailerons and flaps)
  • camber control over four surfaces (I could program it over two surfaces too, but actually I don't need it)
  • crow flaps, with roll control over two or four surfaces
  • fine trimming of both ailerons and flaps for roll or camber

About the plane :

Proxima II, 2.78m, Selig 3021 (Reichard)

MVVS 3.5 / 1200

Castle Creations ICE 50A ESC

Thomas Scherrer RC system

UavDevBoard 4 stabilization / autopilot unit

And finally an amazing board that allowed me to have all those functions mixed with the autopilot.

FpvKiwi Channel Wizard

This mixer is incredibly flexible in programming.

It is fed with PPM stream from RC rx. The UDB is daisy chained to it and feeds back to it again ailerons control for stabilization and autonomous flight.

Attached are the schematics of all the connections :

Here you can watch some more pictures of the plane.

Next plans are to mount a video system and use it as an FPV platform, for long time flying using thermals.

This plane is dedicated to Bill Premerlani, as a tribute to him for starting this amazing adventure, for all the improvements he achieved and for letting me the privilege to travel a short distance on this long road with him.

Thank you Bill !

Best regards,

Last edited by chiloschista; Mar 03, 2012 at 12:02 PM.
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Mar 03, 2012, 04:30 PM
Registered User
Interested to know what video and rc frequencies you'll be using?

Also what part of NZ are you from, I'll be working there for six months later this year.
Mar 03, 2012, 04:31 PM
Registered User
Woops, just saw your location is switzerland. Sorry about the NZ reference, I thought the board with 'kiwi' indicated NZ
Mar 03, 2012, 05:37 PM to put on air 100 models
chiloschista's Avatar
Hi tobermei,

yes, Switzerland, so a bit far away from your location (16341 km).

Video equipment still has to be defined.
I don't know if I'm going to use a Gopro (I don't like the rolling shutter), or a CCD cam. Camera turret ? I like to look around, while doing FPV.
Frequency ? Still to be decided. I have the choice between 2.4GHz, 5.8GHz or 1.3 / 1.2 GHz.

Best regards,

Mar 03, 2012, 06:03 PM
Registered User
Apr 09, 2012, 10:03 PM
Registered User
Hi choloschista. I was flying a Proxima II as an FPV ship on autopilot, until this past weekend when it autopiloted itself into a remote, rugged mountain, the exact location of which I'm not sure.

I was using an APM with AP2.24 software, and FM RCRx (JR Tx and SL-8 Rx) and a 900MHz Vtx/ground station. I'd had many flights on it and was very happy with the performance. In a remote environment (away from urban or microwave RF noise) I was able to fly > 3km and have solid video and RC control.

I used a GoPro (no enclosure) as a wing camera. Initially I used it as the FPV camera, but it has a tendency to cut out so I started using a nice FPV camera a few flights before its final flight. I was flying a 4S power setup at about 800W which made for nice fast launches with 2.65, 4.9 or 5.3 Ah packs.

The Proxima II is a real pleasure to land - it's so well-mannered on approach. It was never a stellar thermal ship, especially after I strapped the GoPro to the wing. It will be greatly missed, as will all the tricked-out goodies I had it loaded up with. I have a high-performance glider to replace it with but am considering also building up another, less expensive glider. I might even try the Sirius, which looks like the Proxima's slightly bigger sister.

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