LOHAN rocket motor igniter goes pop at 20,000m

Test flight an explosive success

Pics+Vid Fans of our Low Orbit Helium Assisted Navigator (LOHAN) mission will know that the issue of getting a rocket motor to fire at altitude has given our Vulture 2 spaceplane team plenty of sleepless nights.

Click here for a bigger version of the LOHAN graphicLast year, we constructed the Rocketry Experimental High Altitude Barosimulator (REHAB) hypobaric chamber (details here), in which we tested a couple of motors at 20mbar – roughly the equivalent of an altitude of 23,300m.

Our first foray into REHAB ended in forlorn fizzling, as both Cesaroni and Aerotech igniters went pop but failed to fire their respective reloads.

Enter stage left pyrotechnics chap Rob Eastwood, who brewed up a custom igniter from E-Matches, BlackMatch strands and Plastic Igniter Cord.

This did the trick in the REHAB chamber, when we finally persuaded a Cesaroni 57F59-12A "White Thunder" reload in a P29-1G casing to roar mightily:

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All well and good, but a high-altitude test flight in July this year, with the same igniter controlled by the Special Project Electronic Altitude Release System (SPEARS) control board, showed that the Plastic Igniter Cord doesn't much like the cold.

So, it was back to the drawing board for Rob, who formulated a new, mightier igniter ahead of jetting out to Spain for our recent LOHAN team gathering.

Priority number one for this elite squad was to test the new igniter, and although first test flight on 16 September went completely titsup due to premature balloon burst, a second blast last Thursday had the champagne corks popping.

Here's the launch site for the flight...

The launch site for our second flight

... right next to the village of Villanueva del Aceral, in the province of Avila (.kmz file of exact spot here):

Google Earth grab showing the launch site

The payload comprised the igniter in an insulated case (bottom right) and a few other pyrotechnic charges we were eyeing for possible use in our emergency balloon cut-down system - all attached to the SPEARS board and set to go off at 20,000m:

The payload for our igniter test flight

Just to clarify, here's a snap showing why LOHAN is the Low Orbit Helium Assisted Navigator:

Two bottles of helium at the launch site

Chief balloon wrangler Dave Akerman worked his usual magic with the mighty orb, and we were quickly in the air without incident:

Dave Akerman begins to fill the balloon

The balloon begins to swell

A view of the second LOHAN launch last week

The balloon in the air immediately before launch

The balloon and payload in the air just after launch

As well as the SPEARS board, the payload carried Dave's Raspberry Picam rig, which has previously returned impressive images from aloft.

On this occasion, Dave fitted a wide-angle converter for the camera, which proved a bit fuzzy at the edges, but did the trick in capturing the downwards view:

View from the Picam

Another view from the Picam at high altitude

The flight prediction* showed the payload would come down within 20km of the launch, so we nipped off to find some shade...

The pursuit van parked up as we wait to see where the payload's headed

...while watching the flight's progress courtesy of the onboard radio trackers:

The tracking laptop on the dashboard of the pursuit van

After half an hour, we moved to another location closer to the predicted touch-down, and whipped out the handheld antenna to get a better fix:

Dave and his handheld antenna as we wait to see where the payload will land

We were so close to the where the payload was expected to hit the ground that we reckoned we'd be able to see it come down...

Paul Shackleton scans the skies

...in a vast area agreeably free of trees, bodies of water, electricity pylons and other hazards which traditionally attract payloads:

The pursuit van parked in the middle of a vast plain as we wait for the payload to land

After just a couple of minutes scanning the skies, we saw our mission end in a field of wheat stubble a couple of hundred metres for our pursuit vehicles. Paul Shackleton was first to the spot...

Paul with the payload in a big flat field of wheat stubble

...which was right here (.kmz):

Google Earth grab of the landing site

So, did the igniter go pop? Yes it did, as Rob and Paul's happy faces show:

Rob and Paul with the recovered payload

Naturally, we also captured the obligatory post-recovery pic, with (from L-R) Claire Edwards, Paul, Dave Akerman and Rob showing their satisfaction with a text-book mission:

The LOHAN team after the successful airborne test of our custom igniter

Naturally, you're going to want proof that we've finally cracked the igniter issue, and here it is:

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Our final challenge is to have the igniter fire a small rocket motor at altitude - something which wasn't possible on this flight due to the possible fire risk hazard of an unfired motor falling in the vast sun-scorched interior of Spain.

When we do that, we'll also reveal just how our improved igniter works - something which must remain classified for the time being. ®


*We'll bring details on just how the magnificent flight predictor works in due course.

Further LOHAN resources:

  • New to LOHAN? Try this mission summary for enlightenment.
  • You can find full LOHAN coverage right here.
  • Join the expert LOHAN debate down at Reg forums.
  • 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 consensual tweeting, as you can see here.

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

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