back to article LOHAN fires up sizzling thruster

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 graphic The thruster in question is an AeroTech RC 32/60-100NS, specifically designed for …


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  1. Sequin

    An alternative igniter

    Big Clive has an igniter here - extremely cheap, probably very reliable, but does require a 12v power source:

  2. Lee T

    LOHAN looking hot


    LOHAN unsure about how much to thrust...


    Looking good, chaps :)

  3. Wombling_Free
    Thumb Up

    Alternate igniters

    Presumably the igniter is doing as simple a job as the super-fragile igniters that come with A to D class rockets you get from hobby stores.

    Back in the day we used a far simpler system that was robust and reliable - a matchstick with a small piece of nichrome wire (fuse wire) wrapped over it. This was inserted in the nozzle of the rocket, 9V was applied and WHOOSH. I'd send a sketch, but I can't. We used to use such igniters for our own air-fired rockets - either rockets slung beneath a glider, or gliders with remote-triggered rocket boost. Fun stuff!

    I must admit to being thoroughly underwhelmed by the noise of the G - the old black-powder D series have quite a loud roar when they fire!

    1. Anonymous Coward
      Anonymous Coward

      Good idea

      Once demonstrated how to set off some home-made gunpowder with a piece of brillo pad wire and a 9v adaptor. I left the idea in the capable hands of my fellow inventors - ie more 2nd year (Scottish) undergrad students - to retire to my room and read a book.

      Not long afterwards I became aware that the air in the flat had a acrid taint. I opened my door to find the corridor uncommonly "cloudy" . When i reached the lounge I discovered that my friends had not "learnt the lessons taught by the British battlecruisers at Jutland" : failure to take adequate anti-flash precautions (they had left the lid off the margarine tub) had meant that a stray spark from the experiment in hand had ignited the reserve of blackpowder.

      The former marge tub was gone, replaced by a sizeable dent in the melamine and underlying chipboard of the table. The breadboard served as a temporary cover against official eyes until a second layer of melamine was added during the Easter hols.

      Anon for usual reasons

  4. horsham_sparky

    Temperature will not be homogeneous across the assembly

    There will be hotspots.. thermal camera would have been best (you would need to shield the exhaust from its view)

    Otherwise, a multi-channel thermcouple data logger would have done the job..

    1. Lester Haines (Written by Reg staff) Gold badge

      Re: Temperature will not be homogeneous across the assembly

      Agreed, but we just needed a rough idea for the design boys. It doesn't look like we'll need to stick the motor in a titanium and kevlar heat enclosure.

      1. horsham_sparky

        Fair enough! Just don't put your electronics anywhere near it, specially radio devices (e.g GPS, radio modem etc). They typically have Temperature or Oven controlled crystals in them to ensure they can tune accurately to the correct radio bands. These might have difficulty doing that if they rapidly move between extremes of temperature

  5. Keller Drozdick

    Good test, questionable units

    Nice test, and I was impressed by the rocket performance, particularly compared to my long ago experience with amateur rocket engines in the US (Estes), which put out huge volumes of smoke.

    However, thrust in grams? Really? Can you not use an anglocentric unit like the Newton at the test center in Spain? Or did you try to compose the video after a trip to the pub, forgetting mass vs. force?

    1. horsham_sparky

      I also wonder if the reading was accurate.. I've noticed on some kitchen scales that the reading varies depending on where on the scale the force is applied.

      sometimes simple isn't always best.. we use force guages for these kind of measurements

      1. Lester Haines (Written by Reg staff) Gold badge


        Fret ye not - I checked that the reading was the same across the scales.

    2. This post has been deleted by its author

  6. Anonymous Coward
    Anonymous Coward

    G-Class AeroTech Copperhead Kit ... GACK?

  7. Flocke Kroes Silver badge

    NAR test results for AeroTech RC 32/60

  8. BernieC
    Thumb Up


    Looks like a sophisticated version of the old Jetex engines I used you use as a kid for model aircraft. Cool stuff.

  9. Mike Moyle


    Solid-fuel rockets, cold temperatures and O-rings...

    I seem to recall hearing something about that combination... now where was it...?

    ...sorry... ...just leaving...

    1. Lester Haines (Written by Reg staff) Gold badge

      Re: Hmmm...

      I'll stick your name down for the post-disaster board of enquiry, shall I?

  10. Dyspeptic Curmudgeon

    Loved the opening of the video, Nice work, Good practice for the upcoming main feature.

    But the sound effects have to go.... that sounded like a puny 4 cylinder Cessna 152 flying by.

    If you are going to do sound, then it should at least be a jet.

    Try this:\

    Or maybe steal the audio from here, and substitute 'Lohan' where necessary.

    Plus of course, it should start with the opening bars of 'Also Sprach Zarathurstra',

    I mean, gee, get with the program, guys!

    1. Lester Haines (Written by Reg staff) Gold badge

      Re: Puny 4 cylinder Cessna 152

      I say, steady on: That'd be a mighty 12-cylinder Merlin throbbing across the soundtrack.

  11. Dyspeptic Curmudgeon


    sed s/Also Sprach Zarathurstra/Also Sprach Zarathustra/

    1. E 2


      echo $COMMENT | sed s/Also Sprach Zarathurstra/Also Sprach Zarathustra/

  12. carter brandon
    Thumb Up

    Love the way you call it a powerplanet so it matches the start of the video.

  13. another_vulture

    Temperature in vacuum

    In addition to worry about hotspots, you also need to remember that convective cooling does not work very well at reduced pressure. Fortunately, in this case the total heat is in bounded because the motor quits after a few seconds. I do hope you continued to monitor the temperature for at least a minute after the end of the burn, since it takes a few seconds at least for the heat to migrate from the inner wall of the chamber.

  14. Graham Marsden

    "it's up to the Southampton Uni boys to tell us if they need more power"

    "We need more thrust, Scotty!"

    "I'm gie'in her all I've got, Cap'n!!"

  15. 8-{>


    Copperheads are more commonly known as "Crapperheads". Essentially they are double sided copper clad filmwire cut in to narrow strips with one end stamped in to a zigzag crinkled shape for about 5 to 10mm and then dipped in a pyrogen. Which, I think, is mixed with carbon to make it slightly conductive/give it enough resistance. As mentioned they are notoriously unreliable.. Often fine copper whiskers from their being guillotined in to strips short the two copper layers out.

    Look for e-matches like Davyfires or similar. These are the proper tool for the job.

    Also there should'nt be any heat issue with the casing temp. Part of the US regs (NFPA 1127 iirc) which the motors must meet to be allow them to be sold define max external temp the motor casing can reach. Also remember that most hobby rockets of the size that take these motors use a cardboard or phenolic impregnated paper/card motor tube for the motor mount. They dont have any issues with the temperature that the casing reaches.

  16. Kevin McMurtrie Silver badge

    Need space for more thrust

    That tiny jet of exhaust is probably creating a vacuum over the nozzle, like a venturi pump would. Since the nozzle cap has more surface area being sucked on than the jet has area being pushed on, atmospheric pressure is not in your favor. This rocket could chemically perform worse in space yet end up producing more thrust.

    Pedantic science nazi: Why put the rocket in a sliding holder for a bathroom scale? Surely you could get the difference in measurements from before and during the test when the whole apparatus is on the scale. How much is a gram in space?

  17. E 2

    Looks good

    Also, the acronyms are fantatastic!

  18. Dave Bell

    I suppose it's too late to suggested a mix of dioxygen-diflouride and sugar as the propellent....

  19. fighne

    temp measurements in reduced pressure

    two things from an old instrumentation technician;

    1) thermocouple connectors are different colours across the cold bridge- leading to incorrect readings

    2) thermocouples need a transfer medium-partial vacuum will lead to incorrect readings

    Back in the day we used laser thermometry in low temperature and partial vacuum in the ultra low fridges at Oxford Instruments

  20. sisk


    It's been quite a while since I've flown model rockets, but it used to be a weekly event. Back in those days of yore when I had time to do things like spend whole days building model rockets and chasing them down I found copperheads to be the bane of my hobby. Sadly they were all I could get around here. As if the failure rate wasn't bad enough, safety pactices (at the time enforced by elders carrying titles like 'Dad') demanded that we take a ten minute break from launching just in case the motor decided to spontaniously ignite. To be fair it did happen on occasion.

  21. Andy 97
    Thumb Up

    Top stuff

    Excellent stuff lads!

    I especially like the authentic Heath-Robinson verification apparatus.

    Much success to you in this project.

  22. Guido Brunetti

    Thrust measurement

    What is the weight of the fuel? You have to add that to the measured thrust over time to get the real thrust. Near the end the real thrust would be the measured weight on the scale plus the weight of the already burned fuel since the initial "0" measurement included the fuel weight.

    So if your fuel weight was, say, 500g, the peak thrust would actually have been measured at roundabout 1900 grams near the end.

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