LOHAN is heading towards REHAB

Garden shed vacuum chamber starts to shape up

We know you lot do wonder just what's afoot down at the Low Orbit Helium Assisted Navigator (LOHAN) fabrication bunker, so we thought we've give you an update on progress on our garden-shed hypobaric chamber experiment.

If you're a LOHAN newbie there's background info on the Rocketry Experimental High Altitude Barosimulator (REHAB) experiment here and here.

In summary, our cunning plan is to put together a low-pressure, low temperature test environment to see if the proposed powerplant for our Vulture 2 aircraft will actually fire at altitude.

Here's the AeroTech RC 32/60-100NS solid rocket motor in question undergoing a first firing test last year:

All well and good, but we need to know if the motor can handle low temperature and pressure. Following extensive consultation with you, our beloved reader experts, we formulated this set-up:

It looked entirely plausible on paper, until the boys down at my local metalworks started to put it together. They were having trouble working out just how to mount the motor inside the contraption, and then one bright spark suggested it would probably be a good idea if the structure holding said motor could be removed, the better to connect the temperature sensor and ignitor.

To do this, he suggested, we should get the pieces cut by one of those plasma beasts which hews parts from the living sheet metal to sub-millimetre accuracy.

Accordingly, we immediately got on the red telephone to Paper Aircraft Released Into Space (PARIS) CAD chap Federico Buenadicha. Naturally, he could just draw the necessary parts, but he decided to render the entire structure (full-scale PDF drawing here, if you're interested):

How the whole thing works is better demonstrated in these views:

As you can see, there's an inner assembly which holds the motor, and which slides neatly into the REHAB inner tube. The motor is offset from the centre, to allow free space to accommodate the cable of the ring-type thermocouple which will be clamped directly to the motor casing.

Federico has drawn the outer chamber as a box, rather than a tube, which gives more room to pack in the dry ice.

What's not shown above is the connection for the vacuum pump, which passes through the base of the inner tube. At the other end will be this fridge compressor, suitably bodged to suck the living daylights out of LOHAN:

So, as you can see, things are progressing nicely. Before we get back to work in the shed, we'll answer the question which is doubtless on everyone's lips: Just who is this Federico Buenadicha of whom you speak?

He's the fella seen here holding the balloon on 28 October 2010, just before our Vulture 1 aircraft soared to a Guinness World Record:

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Further LOHAN resources:

• New to LOHAN? Try this mission summary for enlightenment.
• You can find full LOHAN coverage right here.
• All the LOHAN and Paper Aircraft Released Into Space (PARIS) vids live on YouTube.
• For our SPB photo archive, proceed directly to Flickr.
• We sometimes indulge in light tweeting, as you can see here.