Explode Harder

Electrosonic 2


welcome to the most advanced research project ever, based on Electrosonic, it will feature:

  • overall similar design to Electrosonic. cheap i know.
  • but
  • heavier epoxy-post-tube or PVC construction
  • external-mould nosecone
  • plastic or aluminium fins NO WARPING
  • internal spring-switch for apogee detection
  • motor fittings of steel
  • 2-stage one-piece motor, air-speed re-ignition
  • more powerful rechargeable onboard battery, no swapping
  • more powerful motor developed, 40mm.


    some other ideas that might show up are:

  • phone camera
  • on-board ignition of first stage
  • clockwork or electronic timer for parachute and/or failsafe
  • shrieking piezo location alarm
  • RC ignitor box / launch switch
  • basic altitude sighting and triangulation
  • motor test pressure and thrust monitoring
  • simulation

    12th May
    Work has started on this project. i've been investigating deployment systems, and have part of one working in a crude form. this is a most pressing issue considering what happened to Electrosonic I. though the air-speed switch has worked in quite ambitious rockets for Richard Nakka it has inelegancies:
  • sticks out
  • complex mechanism
  • easy to fool

    alternatives i'd found were magnetic sensing of orientation, photo-comparatory sensing of tip-over and a mechanical free-fall switch mechanism thing. the first two required electronics and the third, i couldn't actually find details about, when i went looking. the first, magnetic detection, relied on a hall-effect chip a bit like a compass, which turned out to be very expensive. it would otherwise no doubt have worked.

    so i proceeded with the 2nd. this involves comparing the voltages of two light-sensing circuits and outputting a voltage when the relationship between the two reverses. one sensor is pointed skyward and one soilward, and they can be either CdS light sensors, or light dependant resistors. all the components seemed relatively available so with some helpful correspondance from the originator of the system, i built a working one.

    there was a fair bit more trial and error and swearing than i have detailed, but i am confident that it will work, with a complete rebuild.

    then of course, i found the mechanical one

    both have shortcomings:
  • mechanisms need to be carefully constructed, electronics doesn't
  • the mechanism is bone-simple and can pass high current
  • the electronics is probably harder to fool

    without actually trying both its hard to know, but i think the mechanical one is harder to test on the ground and could come unstuck if the rocket goes off at an angle. the electronics is more likely to deploy, but it could do so at a high speed, also if the trajectory is crooked.

    maybe i should use both, i haven't decided.













    • Optical apogee detector test circuit =D


    20th May - Nozzle News is Good News

    i've worked out what the nozzles should be like, and am working on the nosecone.

    Bulkhead for bigger motor - blueprint

    Nozzle for smaller motor - blueprint

    Nozzle for bigger motor - blueprint

    i investigated "spinning" the nozzles, but my achievements have been a bit discouraging so far [pics], so i might have to have them machined from "Ledloy" steel.

    the nosecone will be cast in a 3-part plaster mould hopefully, and comprised of reinforced epoxy of some sort. before i can do that, i need to make a wooden blank... [drawing]




    nozzle renders from Blender



    August trans-winter drawings

    after a bit of discussion and to-and-fro with engineers i drew up these plans with a pencil. the idea was that they would be clearer and more legible, all i can really claim is that they have measurements explicitly labeled, instead of a grid you have to squint at.

    click for 1000px

    click for 1000px

    i haven't finished the nosecone form of course, but i have aquired a selection of neodymium-tipped darts. highly lethal, highly magnetical and in attractive red and green colours! do not eat.



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