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Our Vulture 2 rocket spaceplane crammed with more power

She couldna take it, Captain: So we've gone for triple energy podules

Our magnificent Vulture 2 spaceplane is in bits for the last time as we make the final modifications before declaring the aircraft fully operational - at least in the hardware department.

Our Vulture 2's dismantled avioncs

During a recent test, we identified a couple of problems - a dodgy port canard servo and a a lack of juice supplying the Pixhawk autopilot and servos.

The first issue was likely caused when we burned out the starboard canard servo, prompting our plucky Playmonaut to bail out of the smoking aircraft.

Cue another replacement, the installation of which involves removing the entire Raspberry Pi rig and servo mounting platform. A chore, but a minor inconvenience compared to getting more batteries into the rocket ship.

The servo mount platform ready to remove

Originally, we planned to run both Pixhawk autopilot and servos off a single Energizer Ultimate Lithium battery pack, as per this diagram:

Schematic showing all the bits and connections of our Vulture 2 Pixhawk rig

This set-up, taking both Pixhawk and servo rail feeds off the APM Power Module, is highly unrecommended, and in the event, the four batteries simply didn't have enough grunt to operate the servos without the Pixhawk browning out.

So, at autpilot brain surgeon Andrew Tridgell's suggestion, we laid our hands on a Castle Creations Battery Eliminator Circuit (BEC) plus programming unit:

The Castle Creations BEC with programmer

This kit allows us to feed the Pixhawk servo rail from no less than eight AA Energizer Ultimate Lithiums, at a programmable output voltage. The Pixhawk, meanwhile, is powered separately from the original 4 x AA battery pack.

Installing the BEC (and RFD 900u Radio Modem)...

The BEC and radio modem installed in the Vulture 2

...involved removing the Pixhawk GPS/compass unit and sticking it next to our plucky Playmonaut:

The relocated Pixhawk GPS unit

The radio antenna, meanwhile, is well aft on the aircraft's underside, keeping it as far away from the GPS as possible:

The 900Mhz antenna on the Vulture's underside

With all that done, we now have room for all the various battery packs:

The battery packs in our Vulture 2

From left to right, we're packing eight Energizer Ultimate Lithium AAs for the servos, four for the Pixhawk and four AAAs for the Raspberry Pi rig.

That ought to do the trick, and the Vulture 2 will be back on the van roof shortly for a test run with all servos fired up. We already know that the Pixhawk alone will run for at least five hours on four batteries, so the question now is do we have enough separate juice to operate the control surfaces?

While we answer that question, we invite you to show your support for all this hard work down at Kickstarter, where we're rattling the tin for the LOHAN Spaceport America launch. ®


More from the lovely LOHAN:

  • You can find full LOHAN coverage right here.
  • If you're new to LOHAN, seek out our mission summary for enlightenment.
  • There are photos our our magnificent Vulture 2 spaceplane here, and detailed structural plans here.
  • For your further viewing pleasure, we have all our photographic material stored on Flickr.
  • Our LOHAN and Paper Aircraft Released Into Space (PARIS) videos live on YouTube.
  • We sometimes indulge in light consensual tweeting, as you can see here.

LOHAN - A Special Projects Bureau production in association with...

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  • Escher Technologies
  • Flashpoint Fireworks logo
  • HAB Supplies logo
  • Rock 7 logo
  • Random Engineering logo
  • Space Graphic Solutions logo
  • 3D Robotics logo
  • Edge Research Laboratory logo


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