Original URL: http://www.theregister.co.uk/2011/12/20/lohan_motor_test/

LOHAN fires up sizzling thruster

First test of Vulture 2 powerplant

By Lester Haines

Posted in SPB, 20th December 2011 11:01 GMT

Video Things are moving apace at the Low Orbit Helium Assisted Navigator (LOHAN) headquarters, and last weekend we did a first test firing of the proposed powerplanet for the Vulture 2 spaceplane.

Click here for a bigger version of the LOHAN graphicThe thruster in question is an AeroTech RC 32/60-100NS, specifically designed for gliders and without the ejection charge used to deploy the parachute on traditional amateur rockets.

As regular readers will know, we're currently working on the Rocketry Experimental High Altitude Barosimulator (REHAB) experiment, to see if the motor will fire at low pressure and temperature.

However, we thought we'd check out a couple of other performance parameters before sticking LOHAN in REHAB, namely the thrust and external casing temperature. Both are important considerations for our Southampton Uni Vulture 2 design team.

Here's the motor with its G-class reload (clockwise from left: reload, motor case, sealing ring, end cap and nozzle)...

The AeroTech rocket motor components

The reload kit comes with an AeroTech Copperhead ignitor, but since they're legendarily so fragile that just looking at one the wrong way will cause it to fail, we kept it in its cardboard shipping tube until absolutely necessary.

For measuring the temperature, we hooked up a K-type ring thermocouple to a digital thermometer...

Our digital thermometer and ring thermocouple

...and here's our apprentice boffin Katarina with the assembled test rig:

Our apprentice boffin peruses the rocket motor test rig

As you can see, we attached the motor to a large block of wood by means of some steel pipe clips, although it isn't clamped in hard, meaning it can move up and down freely.

The motor is sitting on a set of electronic kitchen scales. The vertical configuration of the motor is because the scales will only work when horizontal. At the top, you can see the connections for the Copperhead ignitor, running ultimately to an ignitor box and a big 12V car battery.

Here's a detailed view of the rig:

Detailed view of the test rig

  1. Copperhead ignitor wire
  2. Motor
  3. Ring-type thermocouple
  4. Pipe clips
  5. Protective Teflon pressure pad

The pressure pad is actually one of those feet you stick under furniture to stop it scratching your parquet floor, but it made the perfect support for the motor to ensure the scales didn't get roasted.

Finally, here's the whole set-up complete with cameras, and ready to roll...

Wide view of the test rig showing video cameras

..and here's our video of the test, for your viewing pleasure:

Once the smoke had cleared, we were interested to note the motor casing didn't get as hot as expected - hitting a mere 82°C - probably due to the insulating effect of the reload's cardboard outer tube.

Regarding thrust, it's up to the Southampton Uni boys to tell us if they need more power. If they do, we'll get it sorted.

And finally, if we do go with the AeroTech motor, we'll have to find an alternative to the Copperhead ignitor. It's a fragile laminated foil conductor affair which isn't robust enough for our purposes and would probably ice up and short out anyway.

Next up on the LOHAN test agenda is the aforementioned REHAB experiment. Watch this space...

A tip of the hat to our LOHAN associates