welcome to the most advanced research project ever, based on
, it will feature:
overall similar design to Electrosonic. cheap i know.
heavier epoxy-post-tube or PVC construction
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:
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
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:
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
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.
September 2012 - preparing to cast first stage
September 12th, 2012
Its been a long, long time, of hmm and ahh and oooeeer. Preparatory noises, extended indecision,
not feeling the space and time to take the next step. The motor housing has been fitted in a testing stand and the pressure gauge has been hooked up, then it has simply sat in the corner, waiting for me.
The next step is a bit of a leap - cook propellant I haven't made in AGES, in unprecedented quantities, with new ingredients and equipment [ok now im overplaying it] and mush it into liner/inhibitor tubes coated with R180 Epoxy, which has me intimidated already.
December 11, 2017 - 8PM
This motor was finally tested. After two years of it sitting in a test stand assembled and ready with ignitors in place, I set a date (and overshot it).
Tested on my Dad’s farm a couple of days before he left for South America, it worked well and scared everything in earshot.
The first stage fired straight away… followed by immediately the second stage. The nozzle blew off and was lost, all fuel was burned / ejected and the casing recoiled into the ground, and broke everything. A set of bathroom scales ($4, tip shop) was sacrificed and the motor casing is rippled, bent and bulged at the bulkhead end. Hydraulic fittings are mangled, pressure gauge survived though.
Thrust and pressure were registered for a very short time and the nozzle was expanding the exhaust well. The design was ultimate faulty, likely packing to much fuel into a single stage, let alone two in the one casing. The difficulty in actually forming and inhibiting the propellant grains to the specification probably caused uncontrolled burning.
December 21, 2017
Ideas for the next design:
1. Keep it simple:
a. 3d printed nozzles in sintered steel if feasible, or turned graphite, or cast concrete.
b. simple threaded bulkhead
c. sealed with setting material, Either Silicone RTV or putty.
2. Design changes:
a. Casing of seamless steel, diameter 60+mm.
b. 3x Bates grains and 1x Moon- or Slot-grain, half/half.
c. single stage with high -to- sustaining thrust curve, moderate burn time.
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