highaltitude.log.20090522

[00:01] <SpeedEvil> then hopefully I'll have time to get the radio sorted, and noise measurements done on 40nm, and then driving licence gotten, and ...
[00:01] <SpeedEvil> 40m
[00:03] <SpeedEvil> Oh - and swap camera parts, so I have a working display on the camera
[00:10] <Laurenceb> is that a portacabin/
[00:12] <SpeedEvil> yes
[00:12] <SpeedEvil> Oh
[00:12] <SpeedEvil> and replace portacabin door, repaint it.
[00:13] <Laurenceb> thats not the standard roof?
[00:14] <Laurenceb> I had a portacabin that size, but it had an overhanging roof
[00:14] <SpeedEvil> I dunno
[00:14] <SpeedEvil> Possibly not
[00:14] <SpeedEvil> I diddn't do the roof :)
[00:16] <Laurenceb> http://www.portakabin.co.uk/productsandservices/ <- wow
[00:16] <Laurenceb> they sell entire buildings :P
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[00:19] <gordonjcp> yup
[00:19] <gordonjcp> not even expensive, either
[00:19] <Laurenceb> http://www.ukcabins.com/cabin-search/office/cabin/prod79/small-portable-office-unit.html <- I used to have one of those
[00:19] <Laurenceb> suprisingly heavy
[00:19] <SpeedEvil> It has a lifting hook, so I'm replacing the door, painting it properly, adding insulation, sealing, oxygen systems, parachute, and it's good for high altitude connected to a balloon.
[00:20] <Laurenceb> we managed to move it with a hyab
[00:20] <Laurenceb> haha
[00:21] <Laurenceb> but they weigh a lot more than a typical crate of bricks
[00:22] <SpeedEvil> depends on the rigging to some degree
[00:22] <SpeedEvil> but they're what - 1mm*25m^2 of steel
[00:22] <Laurenceb> mine was coated plywood
[00:22] <SpeedEvil> that's about 300Kg right there, neglecting anything else
[00:23] <SpeedEvil> the above is steel
[00:23] <Laurenceb> watch out for wasps nests in the roof :p
[00:24] <SpeedEvil> it's a translucent fibreglass roof
[00:24] <SpeedEvil> It is equipped with an auto-cleaning system to remove algae buildup.
[00:24] <SpeedEvil> AKA slugs
[00:26] <Laurenceb> lol
[00:42] <SpeedEvil> http://www.comparethemeerkat.com/home
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[00:52] <Laurenceb> lol
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[01:07] <Laurenceb> I cant work out these um12 modules
[01:07] <Laurenceb> they have a 100mm 434mhz ant
[01:07] <Laurenceb> maybe a helix of some sort?
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[02:18] <Laurenceb> http://www.micromo.com/servlet/com.itmr.waw.servlet.Anzeige?fremdaufruf=ja&kdid=40929&sprachid=1&htdigurl=/n179257/i95306.html
[02:18] <Laurenceb> ^ for very small valve operation
[02:23] <SpeedEvil> if this is for reaction control, it's gotta be able to respond at 10Hz or greater
[02:24] <SpeedEvil> I suspect solenoid + rare-earth magnet is going to be simplest
[02:24] <SpeedEvil> especially if per-stage on-time is going to be under a minute or two
[02:30] <Laurenceb> it works out pretty heavy for the force
[02:30] <Laurenceb> but yeah you could overdrive a lot
[02:31] <Laurenceb> my 7Kg design is rather tricky, you end up with <100grams for the final stage
[02:31] <Laurenceb> (dry weight)
[02:32] <Laurenceb> still, 4 of those motors is only 10 grams...
[02:33] <Laurenceb> you could have a lipo based supply built into each stage, then a fibre optic "interstage bus"
[02:34] <Laurenceb> the top bulkhead could have an ullage vent valve built in for roll control
[02:34] <Laurenceb> then one of those motors fixed on
[02:37] <Laurenceb> then three motors around the nozzel
[02:44] <Laurenceb> your looking at a 30gram solenoid to get the same performance as a 3 gram gearmotor
[02:46] <SpeedEvil> Dunno - not done the numbers
[03:17] <Laurenceb> basically you can use the gearmotor shaft to drive a ball valve
[03:18] <SpeedEvil> to properly get into it, I'd have to work out orifice sizes, flow rates, pressure drops, ...
[03:18] <SpeedEvil> you planning on a simple pressure fed blowdown type?
[03:18] <Laurenceb> this is just for attitude control
[03:18] <Laurenceb> yes
[03:19] <Laurenceb> CF tube
[03:19] <Laurenceb> with some bulkheads built into it
[03:19] <Laurenceb> then three vavles around the engine injecting methanol for attitude control
[03:19] <SpeedEvil> this is a what/what hybrid?
[03:20] <Laurenceb> notrous HDPE
[03:20] <SpeedEvil> extra nitrous may be an option for the injectant
[03:20] <Laurenceb> it would erode the graphite nozzel
[03:21] <SpeedEvil> maybee
[03:21] <Laurenceb> you could easily have a plastic pouch of methanol inside the nitrous tank
[03:22] <SpeedEvil> 0h - nitrous
[03:22] <SpeedEvil> Was still thinking biprop
[03:22] <SpeedEvil> that's self-pressurising - to a degree anyway
[03:23] <Laurenceb> yeah sure
[03:24] <Laurenceb> 700 to 1000psi
[03:24] <SpeedEvil> at least at the start
[03:25] <Laurenceb> if it was balloon fired you could stick in some heaters powered off the balloon
[03:26] <SpeedEvil> I mean - as it empties - it cools
[03:26] <SpeedEvil> and vapour pressure goes down
[03:26] <SpeedEvil> so chamber pressure falls, and ...
[03:26] <Laurenceb> yeah that sucks
[03:27] <Laurenceb> for something large you could use a kevlar aircraft oxygen cylinder filled with helium
[03:27] <SpeedEvil> stuff like heating using conducted exhaust heat works
[03:27] <Laurenceb> hmm
[03:27] <SpeedEvil> but of course is tricky
[03:28] <Laurenceb> its at the wrong end
[03:28] <SpeedEvil> that too
[03:28] <SpeedEvil> chamber rather than exhaust I mean
[03:28] <Laurenceb> hmm resistors + lipo cell
[03:28] <Laurenceb> you only have to boil enough to fill the ullage space
[03:28] <SpeedEvil> lipo cell + no resistor
[03:28] <Laurenceb> lol
[03:29] <Laurenceb> exploding lipo cells
[03:29] <SpeedEvil> ullage balloon then?
[03:29] <Laurenceb> hmm some sort of gas generator?
[03:30] <Laurenceb> ooh wolfram alpha has phase diagrams
[03:30] <SpeedEvil> I was for my H2O2/kero design (also had a LOX/propane) planning on a H2O2 decomposer in the tank
[03:30] <SpeedEvil> bet it doesn't have fun ones
[03:30] <SpeedEvil> niobium/copper
[03:30] <SpeedEvil> ...
[03:31] <SpeedEvil> niobium is nice in that it's cheapish and refractory
[03:32] <SpeedEvil> unfortunately, it's very reactive once it loses the oxide film
[03:33] <SpeedEvil> Rhenium/iridium is the alloy of choice
[03:33] <SpeedEvil> unfortunately, it's slightly more expensive than platinum.
[03:34] <SpeedEvil> It's lovely - you can do radiation cooled chambers
[03:34] <SpeedEvil> operating at 3000K
[03:34] <SpeedEvil> Or nearly
[03:36] <Laurenceb> http://www16.wolframalpha.com/input/?i=nitrous+oxide
[03:36] <Laurenceb> awsome
[03:38] <Laurenceb> 1.2g/cm^3 has got to be wrong
[03:39] <SpeedEvil> why?
[03:39] <Laurenceb> for gas
[03:39] <SpeedEvil> that'll be liquid
[03:39] <Laurenceb> yeah
[03:40] <SpeedEvil> oh
[03:40] <SpeedEvil> that's screwed up
[03:40] <SpeedEvil> 'gas properties' ... 'surface tension'
[03:41] <Laurenceb> lol
[03:42] <Laurenceb> hmm looks like resistor heaters are going to take a stupid amount of poser
[03:43] <Laurenceb> a few hundered KJ over ~ 10 seconds or so
[03:44] <SpeedEvil> you are keeping the tank pressure at what?
[03:45] <SpeedEvil> if you have an isolated balloon, with a small amount of liquid that you heat - with the balloon thermally isolating it - it's not nearly as bad as if you try to heat the whole mass of the tank
[03:47] <SpeedEvil> also - it's not so critical for the latter stages, as gravity is effectively lower, so are your gravity losses due to lower thrust
[03:51] <Laurenceb> hmm
[03:51] <Laurenceb> ideally you want to keep the tank above 600psi
[03:53] <SpeedEvil> you want to carefully look at that
[03:54] <SpeedEvil> expansion ratios, nozzle sizes, and the actual effect of going for a non optimally expanded nozzle
[03:54] <Laurenceb> yes
[03:55] <SpeedEvil> (keeping the thrust constant and dropping the chamber pressure implies a larger throat and an underexpanded exhaust for a constant nozzle diameter)
[03:55] <SpeedEvil> the optimisations are nasty
[03:55] <Laurenceb> I dont understand your balloon idea
[03:56] <SpeedEvil> taking water as an example
[03:56] <SpeedEvil> You want to keep a pressure of 10PSI over atmospheric in the water
[03:57] <SpeedEvil> this means you can either heat the body of the water to 120C or so, and let it naturally boil off, and pressurise the ullage space
[03:57] <SpeedEvil> Or, you can have a relatively insulated balloon, filled with steam/water at 120C
[03:58] <SpeedEvil> and the main body of the fuel is allowed to cool as it boils off
[03:58] <Laurenceb> so you use the thermal mass of the fuel for heating?
[03:58] <SpeedEvil> if you simply vent hot gas into the ullage space without a membrane of some sort, it'll just condense quite rapidly
[03:59] <SpeedEvil> no - it's not to use it for heating - it's to prevent it from making your task of heating the gas in the ullage space harder
[03:59] <SpeedEvil> Maybe I'm completely wrong though - it's 4AM, and I haven't thought about this sort of rocket before.
[03:59] <Laurenceb> he
[04:00] <SpeedEvil> A little cylinder of helium would be lovely.
[04:00] <Laurenceb> not for the upper stage(s)
[04:00] <SpeedEvil> but at 600PSI - it's not really that little - in comparison to the rest of the stage
[04:01] <SpeedEvil> remember - for the lower stage at least - fuel is cheap
[04:01] <Laurenceb> yeah 3000psi aviation cylinders would be good for the first and maybe second stage
[04:01] <SpeedEvil> Doubling the rocket length - if it makes it much easier to build - do you care?
[04:03] <SpeedEvil> For example - if you end up going with a tank with twice the nominal volume, pressurised to 900PSI with a little He balloon.
[04:03] <Laurenceb> why the balloon?
[04:04] <SpeedEvil> to keep the He out of the exhaust, during starts
[04:04] <SpeedEvil> I'm not sure how soluble He is in nitrous
[04:04] <Laurenceb> not at all
[04:04] <Laurenceb> theres a few papers of he perssurisation of the ullage space
[04:05] <SpeedEvil> but - for the second stage for example, how do you ensure that the He bubble won't get ingested
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[10:13] <rjharrison> ping jcoxon
[10:25] Nick change: kingj -> KingJ
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[10:28] <Futurity> hi everyone
[10:28] <jcoxon> hey Futurity
[10:28] <Futurity> Hi jcoxon
[10:28] <Futurity> i was talking to a member of the Cambridge SpaceFlight team
[10:29] <jcoxon> oh cool
[10:29] <Futurity> i think he may have mentioned your name
[10:29] <Futurity> did you have some involvement in the past?
[10:29] <jcoxon> quite possibly
[10:29] <jcoxon> yes, i graduated from cambridge 2 years ago
[10:29] <Futurity> i think he may have said you were one of the founder members
[10:29] <Futurity> my memory isn't great though ;)
[10:29] <Futurity> oh i see
[10:30] <Futurity> very interesting projects you've been up to
[10:30] <jcoxon> :-)
[10:30] <Futurity> are you still involve at the Cambridge site?
[10:30] Nick change: KingJ -> kingj
[10:30] <jcoxon> yeah i was there at the beginning
[10:30] <Futurity> i think that's what he said
[10:30] <Futurity> let me get his name
[10:30] <Futurity> IRC name that is ;)
[10:30] <jcoxon> ummm, in part - what happens these days is that we all help each other out
[10:31] <jcoxon> so people work on projects in small groups or individually and then everyone helps with launching and tracking
[10:31] <Futurity> edmoore :)
[10:31] <Futurity> good chap
[10:31] <Futurity> had a very good chat with him
[10:31] <jcoxon> oh ed yes, he is around often on this channel
[10:32] <Futurity> shounds like a good way of working
[10:32] <jcoxon> at present rjharrison and I are working on our Distributed listening system
[10:32] <Futurity> doing your own thing or in small teams and then help out on launch days sound like a very friendly helpful hobby
[10:33] <jcoxon> Futurity, yes it is
[10:33] <Futurity> well less hobby, not full time persuit ;)
[10:33] <jcoxon> hehe
[10:33] <jcoxon> we are quite happy to help with most launches
[10:33] <Futurity> Distributed listening system
[10:33] <Futurity> sounds very cool
[10:33] <jcoxon> yes, its getting cooler as we work on it
[10:33] <Futurity> lol
[10:33] <jcoxon> just need to test the latest version on a flight
[10:33] <Futurity> what is its main application may i ask
[10:34] <jcoxon> as in the UK we can't use APRS its quite hard to track a payload
[10:34] <Futurity> listening as in audio, or monitoring ?
[10:34] Nick change: kingj -> KingJ
[10:34] <jcoxon> so this is an adapted version of fldigi (a soundcard decoder program
[10:34] <jcoxon> so you have a radio and laptop/computer and tune into the freq of the radio on the payload
[10:34] <jcoxon> as the data comes in it is automatically parsed and uploaded to our server
[10:35] <jcoxon> which combines all the inputs from the various receivers dotted around hte area
[10:35] <jcoxon> and plots them onto a map
[10:35] <jcoxon> in semi real time
[10:35] <Futurity> very nice
[10:35] <Futurity> so you have multiple radios listening in
[10:35] <jcoxon> yes
[10:35] <Futurity> all receiving the data
[10:35] <jcoxon> yup
[10:36] <Futurity> and then feeding it to a central server that I suppose deduplicates the data arriving
[10:36] <jcoxon> e.g. http://maps.google.com/?q=http://www.robertharrison.org/listen/receivers.php&t=p
[10:36] <jcoxon> yes, it allows you to miss strings yet when all combined together have a full flight
[10:36] <jcoxon> the plan is to also compare these strings to avoid errors
[10:37] <Futurity> Wow
[10:37] <Futurity> very serious effort going on i see
[10:37] <Futurity> i imagines people driving around in cars
[10:37] <Futurity> but then you'd need directional aerials to track it?
[10:38] <jcoxon> i've got good data with just a whip
[10:38] <jcoxon> but something like a yagi certainly makes it easier
[10:38] <Futurity> whip? omni directional aerial on a car?
[10:38] <jcoxon> yes
[10:38] <Futurity> sorry only just studying for my Foundation exam LOL
[10:39] <Futurity> Inherited a VHF / UHF transceiver and am finally getting around to using it
[10:39] <jcoxon> oh i only have a foundation licence
[10:39] <Futurity> in fact is was the SpaceFlight site that got me interested ;)
[10:39] <jcoxon> as we don't actually use amateur radio bands you don't need a licence
[10:40] <jcoxon> but doing hte course helps with technical stuff
[10:40] <Futurity> then stumbled across edmoore and this chatroom while in #hamradio
[10:40] <Futurity> yep
[10:40] <gordonjcp> morning
[10:40] <Futurity> i know most of the intermediate electronics
[10:40] <jcoxon> thats good
[10:40] <Futurity> done PIC probramming in the past as well
[10:41] <Futurity> but more a Java / PHP developer
[10:41] <jcoxon> so planning a payload then?
[10:41] <jcoxon> :-)
[10:41] <Futurity> don't a fair amount of multithreaded Server programming in Java
[10:41] <Futurity> well only been 2 days since I've actually spoken to edmoore
[10:41] <Futurity> but yes, would love to make a payload
[10:42] <jcoxon> Futurity, where are you based?
[10:42] <Futurity> I'm in Melbourn, just south of Cambridge
[10:42] <Futurity> Very near Royston
[10:42] <jcoxon> and you have a uhf radio + a laptop...
[10:42] <Futurity> work part-time on Cambridge Science park as an IT consultant
[10:42] <Futurity> yep
[10:43] <jcoxon> would you like to become a distributed listening station ?
[10:43] <jcoxon> :-)
[10:43] <Futurity> yep have both of those things :)
[10:43] <jcoxon> i'm always recruiting people
[10:43] <Futurity> and would love to get involved in a lunch
[10:43] <jcoxon> the big question right now is what OS do you run
[10:43] <jcoxon> we have it working on mac and linux
[10:43] <jcoxon> windows is causing a few issues
[10:43] <Futurity> LOL
[10:43] <Futurity> On a MAC / Hackintosh as we speak
[10:44] <jcoxon> amazing
[10:44] <jcoxon> i develop on a mac, rjharrison is on linux
[10:44] <Futurity> and run a Linux compute farm as my part-time consultance role
[10:44] <Futurity> distributed computing using Grid Engine
[10:44] <Futurity> At home I run Linux web servers
[10:44] <jcoxon> yes i guess our 'distributed' is a little different
[10:45] <Futurity> on softraid mainly
[10:45] <jcoxon> cool
[10:45] <Futurity> yes you have distributed sensors feeding data into a central location
[10:45] <jcoxon> well if you have 5 mins at any point i'd like to test out hte new DL client
[10:45] <Futurity> sure
[10:45] <Futurity> perhaps later on today
[10:45] <jcoxon> its hard to test here as i have all the libs installed etc
[10:45] <jcoxon> sure
[10:46] <Futurity> Have Windows on the laptop right now
[10:46] <Futurity> but can either install vmware
[10:46] <Futurity> or swap the harddrive and install linux onto it
[10:46] <jcoxon> unfortunately its cygwin that is our issue
[10:46] <jcoxon> compiling the code is causing issues
[10:46] <Futurity> cygwin can be really nasty
[10:47] <Futurity> I tried it
[10:47] <jcoxon> as we've adapted another program which it self doesn't compile cleanly anylonger on cygwin
[10:47] <Futurity> got it to work, but it made the whole machine so slow i gave up on it
[10:47] <jcoxon> they haven't updated their website with the new methods
[10:47] <jcoxon> rather annoying
[10:48] <Futurity> so i take it you are transmitting headers at the start of a row's data, followed by the data
[10:48] <Futurity> so that you can identify frames of data and reassemble them?
[10:48] <jcoxon> from the payload?
[10:48] <Futurity> yes
[10:48] <jcoxon> the protocol of choice is rtty
[10:49] <jcoxon> and we have a 'standardised' telemetry format
[10:49] <jcoxon> $$,callsign,cycle,time,lat,lon,alt,value1,value2\n
[10:49] <jcoxon> so our code searches recived data for $$ and then starts parsing hte data
[10:50] <Futurity> cool
[10:50] <jcoxon> but actually with the new system you can define pretty much what ever telemetry format you want
[10:50] <jcoxon> as each flight has its own xml of info defining the format, freq and other info
[10:50] <Futurity> so i take it that when you are that high above the earth, you get a very good signal range
[10:50] <jcoxon> the client grabs that off the server and uses it configure the client
[10:50] <Futurity> although are you limited on transmission power?
[10:51] <jcoxon> yes, an excellent rage
[10:51] <jcoxon> we are limited to 10mW
[10:51] <jcoxon> but that gets us a couple of hundred miles
[10:51] <Futurity> wow
[10:51] <Futurity> on an omni directional aerial?
[10:51] <Futurity> so that you can pick it up from any direction?
[10:51] <jcoxon> yes
[10:51] <jcoxon> but as i said a directional one is better
[10:52] <Futurity> but i take it you get a fairly noisy signal received?
[10:52] <jcoxon> i'm based in south london and can track most flights after it reaches about 1km altitude
[10:52] <Futurity> wowo
[10:52] <jcoxon> you'd be suprised
[10:52] <jcoxon> the server counts the number of lines you submit - its a little bit of a competition
[10:52] <Futurity> i think the bugs i used to build as a kid had a good few mile range
[10:53] <Futurity> and that's detecting them on an FM radio
[10:53] <jcoxon> :-)
[10:53] <Laurenceb> I'm planning to test a data module soon
[10:53] <Futurity> and ran from a 9V battery for hours
[10:53] <Laurenceb> - commercial serial link
[10:53] <Futurity> Hi Laurenceb
[10:54] <Laurenceb> hi :P
[10:54] <Futurity> so is the transmitter a commercial product?
[10:54] <Futurity> hence the power restrictions?
[10:54] <Laurenceb> previously we've used radiometrix modules with a uC
[10:54] <Laurenceb> I'm going to try a module based on a texas instruments transceiver ic
[10:55] <Laurenceb> the power limit is imposed by OFCOM
[10:55] <Futurity> i see
[10:55] <Futurity> just out of insterest, i think i read that most launches cost £500
[10:55] <Futurity> is that mainly for insurance
[10:55] <jcoxon> Futurity, it should be less then that
[10:56] <Futurity> or ballon / gas?
[10:56] <jcoxon> especially if you smile sweetly at CUSF who might provide helium
[10:56] <Futurity> lol
[10:56] <jcoxon> we don't get insurance
[10:56] <Futurity> i can understand that
[10:56] <jcoxon> unfortunately the insurance companies ask for too much
[10:56] <jcoxon> in the 1000s
[10:56] <Futurity> do you recover most payloads?
[10:56] <jcoxon> yes
[10:56] <jcoxon> we've recently had a good track record
[10:56] <Futurity> that's very cool
[10:57] <jcoxon> we are better at prediciting hte flights so know now when not to launhc
[10:57] <Futurity> and do you transmit a signal to release the payload, or is it timer only?
[10:57] <jcoxon> its timer
[10:57] <jcoxon> we haven't got uplink working yet
[10:57] <jcoxon> though a number of people are working on it
[10:57] <Futurity> i've seen that you can now make your own zero pressure difference ballons
[10:57] <Futurity> very impressed
[10:58] <Futurity> i suppose with remotely releasing the payload
[10:58] <Futurity> noise could be interpreted as a release signal
[10:58] <jcoxon> yup
[10:58] <Laurenceb> I plan to test uplink on my next flight
[10:58] <Laurenceb> with the data modules
[10:58] <jcoxon> bbiab
[10:59] <Futurity> are there any launches planed in the near future?
[10:59] <Laurenceb> rjharrison is launching soon
[11:00] <Laurenceb> I plan to test my payload by hanging it off his
[11:00] <Futurity> i see
[11:01] <Futurity> great that you share launches
[11:01] <Futurity> i take it that most launches are to test transmitters / data?
[11:02] <Laurenceb> more or less
[11:02] <Laurenceb> I'm working on gliders to return to base
[11:02] <Futurity> or are you taking measurements for additional research (or is this just useful date to transmit?)
[11:03] <Futurity> LOL, i was actually going to ask if anyone had some windspeed data so that I could try and model exactly that
[11:03] <Futurity> been years since I've done any real model flying
[11:03] <Futurity> but there are now sensors you can get for automatically flying level etc
[11:04] <Futurity> i think they yse the horizon to provide the level data
[11:04] <Futurity> but i was thinking that i'd have to invert that in the upper atmosphere
[11:04] <Futurity> space dark, ground / air light
[11:04] <Laurenceb> nope
[11:05] <Futurity> where as near the ground they work on ground dark and sky light
[11:05] <Laurenceb> thermopiles work
[11:05] <Laurenceb> they work off inrasred
[11:05] <Futurity> oh i see
[11:05] <Laurenceb> I made an experimental unit a while ago
[11:05] <Futurity> are they confused by the sun?
[11:05] <Laurenceb> but an IMU is a better way to go
[11:05] <Futurity> i suppose you have a much bigger earth giving off heat
[11:06] <Futurity> compared with the sun as a spot source
[11:06] <Futurity> i was considering doing this using my foam delta shapped glider
[11:07] <Futurity> shouldn't cause too much damage if it its something or someone
[11:09] <Laurenceb> tecnically illegal
[11:09] <Laurenceb> you cant fly a UAV like that without a license
[11:10] <Laurenceb> if you fly a "directional parachute" your ok
[11:10] <Laurenceb> you could have a chute that deploys near the ground... its all a bit of a grey area
[11:17] <Laurenceb> I'm flying a rogallo wing with center of gravity shift steering
[11:23] <Futurity> not heard of those either
[11:23] <Futurity> but sounds very interesting
[11:23] <Futurity> how are you going to measure wind speed?
[11:23] <jcoxon> rogallos are like handgliders
[11:23] <jcoxon> designed by the same guy
[11:23] <Futurity> oh i see, hence the centre of gravity
[11:24] <jcoxon> they were then developed by nasa as a potential vehicle
[11:24] <Futurity> how would you avoid stalling?
[11:24] <Futurity> are you going to measure your windspeed?
[11:24] <Futurity> and dip the nose when you start to stall?
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[11:26] <Futurity> Sorry if these questions are very basic
[11:26] <Laurenceb> wikipedia has a good article on them
[11:26] <Futurity> Hi edmoore
[11:26] <edmoore> good morning
[11:26] <Laurenceb> hi ed
[11:26] <edmoore> s'up lau
[11:26] <Laurenceb> how your nprize entry going?
[11:27] <Laurenceb> http://www.stanford.edu/~cantwell/News_articles_on_our_work/AviationWeek_Feb20_03.pdf
[11:28] <Laurenceb> Futurity: they recover from stalls very well
[11:28] <Laurenceb> and if you trim them right they dont stall much anyway
[11:28] <edmoore> it's not. pointless question
[11:29] <Laurenceb> :P
[11:29] <Laurenceb> you need a lox/wax hybrid
[11:29] <edmoore> right
[11:30] <Laurenceb> 2 stage, balloon launch
[11:30] <Futurity> Is anyone close to getting to even one orbit yet?
[11:30] <Laurenceb> what, with the n prize?
[11:30] <Laurenceb> I seriously doubt anyones even close to taking off the ground yet
[11:31] <Futurity> lol
[11:31] <Laurenceb> well apart from CU spaceflights suborbital rocket
[11:31] <Futurity> oh i see
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[11:32] <Laurenceb> edmoore: apparently someone "requested" topsat photos of cambridge
[11:32] <Laurenceb> bah hes gone
[11:32] <Futurity> well they have a fair height, but I don't think they are planning to attempt orbital flight
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[11:32] <Futurity> he's back
[11:32] <Laurenceb> edmoore: apparently someone "requested" topsat photos of cambridge
[11:32] <edmoore> not I
[11:33] <Laurenceb> ok... somethiung to do with cu spaceflight
[11:33] <Laurenceb> well nvm
[11:33] <SpeedEvil> The OSM people have requested imagery
[11:33] <Futurity> edmoore: are there any launched planned from Cambridge in the near future? Is Cambridge the main launch site?
[11:33] <edmoore> yes yes
[11:33] <SpeedEvil> they got pointed at a commercial mapping firm - by the topsat admin
[11:33] <Laurenceb> OSM? wat
[11:33] <SpeedEvil> OpenStreetmap
[11:33] <Laurenceb> oh I see
[11:34] <SpeedEvil> implying they may have sold the rights to the imagery
[11:34] <edmoore> well, there isn't one planned any more than that there will be a couple in the next month
[11:34] <Laurenceb> SpeedEvil: we run the sat here
[11:34] <SpeedEvil> ?
[11:35] <Laurenceb> topsat
[11:35] <jcoxon> Futurity, there might be a launch on sun/mon
[11:35] <edmoore> it's an SSTL bird
[11:35] <jcoxon> from EARs
[11:35] <Futurity> is there a mailing list i can subscribe to?
[11:35] <SpeedEvil> Laurenceb: yes - but running the sat, and having the rights t the imagery, ...
[11:35] <Laurenceb> heh
[11:35] <jcoxon> Futurity, http://groups.google.com/group/ukhas
[11:35] <Laurenceb> yeah the admin is a bit more complex
[11:35] <Futurity> I've heard that Monday will be a very rainy day (as of last night's weather predictions)
[11:35] <jcoxon> but i can't promise it gets used that much
[11:36] <jcoxon> rain, pah - its teh JS we are most concerned about :-)
[11:36] <Laurenceb> rain... who cares
[11:36] <SpeedEvil> Laurenceb: much of the UK - the only imagery which can be used to trace over for purposes of mapping is Yahoo imagery - which sometimes degrades to landsat - with 15m pixels
[11:36] <Laurenceb> :P
[11:37] <SpeedEvil> 2.5m would be a significant improvement
[11:37] <Laurenceb> SpeedEvil: yahoo dont mind that?
[11:37] <SpeedEvil> they have said it's OK
[11:37] <jcoxon> Futurity, present forecast i'd say sunday is best anyway
[11:37] <Laurenceb> interesting
[11:37] <SpeedEvil> google have said it isn't
[11:37] <Laurenceb> yeah
[11:37] <jcoxon> finally a break in hte JS
[11:38] <Laurenceb> well topsat was taxpayer funded, so ...
[11:38] <Futurity> lol, good point, rain isn't experienced for long. I'm such a lamer ;)
[11:38] <jcoxon> its actually quite annoying getting wet
[11:39] <jcoxon> but we clear its pretty quickly
[11:39] <SpeedEvil> Laurenceb: haha.
[11:39] <SpeedEvil> Laurenceb: :/
[11:39] <Laurenceb> well the least you can do is moan at them
[11:39] <SpeedEvil> Laurenceb: the current theme in governmental projects seems to be sell rights to data to offset costs of probjects
[11:40] <Laurenceb> the good thing about the US is government projects are more accountable
[11:40] Action: Laurenceb points to the datasource for CU landing spot prediction
[11:41] <edmoore> ?
[11:41] <edmoore> oh gfs
[11:41] <edmoore> sorry slow day
[11:42] <Laurenceb> the selling rights approach gets very close to government subsidising industry
[11:42] <Laurenceb> which shouldnt be part of their job IMO
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[11:46] <SpeedEvil> Laurenceb: yes
[11:46] <Futurity> out of interest, are you banned from using a mobile phone on the payload to transmit data?
[11:47] <SpeedEvil> Futurity: it doesn't work over 200m or so
[11:47] <Laurenceb> SpeedEvil: with LOX/parafin wax you can get an ISP of 340
[11:47] <SpeedEvil> Futurity: the antennas are sharply pointed horizontally
[11:47] <jcoxon> we use them on when the payload lands
[11:47] <Laurenceb> good enough for two stage to orbit
[11:47] <jcoxon> as the radio isn't as good
[11:47] <SpeedEvil> Laurenceb: fun
[11:47] <Futurity> i see
[11:47] <Laurenceb> Futurity: its another grey area
[11:48] <Futurity> good to know that the world of radio is not orange but grey
[11:48] <Laurenceb> you could argue the phone turns its transmitter off
[11:49] <Laurenceb> it doesnt see and basestationms at altitude
[11:50] <Laurenceb> *any
[11:50] <Laurenceb> or just program your flight computer not to attempt to send messages
[11:50] Action: SpeedEvil ponders a lithium/flourine hybrid
[11:51] <Laurenceb> lol
[11:51] <Laurenceb> http://www.stanford.edu/~cantwell/News_articles_on_our_work/AviationWeek_Feb20_03.pdf
[11:52] <SpeedEvil> yeah - checking - yahoo has landsat only for my area
[11:52] <SpeedEvil> it's sort of 'can guess where roads are'
[11:52] <SpeedEvil> 15m pixels
[11:55] <Laurenceb> guess the problem with lox is making a tank that will hold it
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[11:56] Action: SpeedEvil cues bad prison escape movie soundtrack.
[11:57] <gordonjcp> SpeedEvil: they updated the googlemaps imagery for around Skye
[11:57] <gordonjcp> unfortunately it's a few years old, so it shows all the old cars and shite that were lying around my place
[11:57] <Laurenceb> hehe
[11:58] <SpeedEvil> _slowly_ getting my place in order.
[11:58] Action: SpeedEvil only has one old car, but lots of shite.
[12:00] Action: SpeedEvil sighs.
[12:00] <SpeedEvil> Another entry on my stack is to solder, configure, and install a replacement ECU in it. fun.
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[12:01] <Laurenceb> a spare ECU?
[12:04] <SpeedEvil> no - megsquirt
[12:04] <SpeedEvil> mega
[12:04] <SpeedEvil> opensource ECU
[12:06] <jcoxon> hi jockc welcome to #highaltitude
[12:06] <jockc> hi
[12:07] <SpeedEvil> hi
[12:07] Action: SpeedEvil also has a balloon on the same stack at some point. And a UAV.
[12:33] <Laurenceb> what can you control with the ECU?
[12:36] <gordonjcp> fuel injection
[12:37] <jockc> spark & fuel, you can put other things onto it to control Nitrous oxide/water injection/VVT etc. iirc
[12:37] <SpeedEvil> Laurenceb: yeah - spark and fuel
[12:38] <Laurenceb> SpeedEvil: deisil or petrol?
[12:38] <SpeedEvil> Laurenceb: not for performance as such
[12:38] <SpeedEvil> Laurenceb: well - to make it go
[12:38] <SpeedEvil> Laurenceb: petrol 1.8 4cyl
[12:38] <SpeedEvil> Laurenceb: the existing ECU is either broken, or needs re-keying
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[12:39] <Laurenceb> interesting
[12:39] <SpeedEvil> attempting the second would cost a sizeable fraction of the price of the car, and the first too.
[12:39] <Laurenceb> I'd go for deisel
[12:39] <SpeedEvil> this is a second car
[12:39] <SpeedEvil> basically, most of the time it'll be SORN'd, and uninsured
[12:39] <gordonjcp> SpeedEvil: what kind of car? I know you've told me
[12:40] <SpeedEvil> only getting a tax disk and insurance when it's needed - for moving heavy stuff forex
[12:40] <Laurenceb> of course if you have an old deisel it'll have mechanical injection unit
[12:40] <SpeedEvil> renault laaguna
[12:40] <gordonjcp> SpeedEvil: I'm sure you can pick an ECU up out of a scrappy for next-to-nothing
[12:40] <SpeedEvil> Laurenceb: getting to be quite old indeed to havee mechanical
[12:40] <SpeedEvil> gordonjcp: well - yes
[12:40] <Laurenceb> SpeedEvil: only 5 years or so?
[12:41] <gordonjcp> find out what kind of ECU and I'll dig in the Great Big Bumper Fun Box of Shite
[12:41] <SpeedEvil> gordonjcp: but - the problem of getting it actually working arises
[12:41] <SpeedEvil> gordonjcp: keys and IR recievers, and stuff
[12:41] <gordonjcp> hmm, yeah
[12:41] <SpeedEvil> gordonjcp: will do - possibly today
[12:41] <gordonjcp> I hate that shit
[12:41] <gordonjcp> my XM had a keypad behind the gearstick
[12:41] <gordonjcp> I don't understand the advantage in transponder keys, people just break in and steal the keys
[12:42] <SpeedEvil> It's sane enough for new cars - but is just making old ones pointlessly hard to service
[12:42] <gordonjcp> like what happened to my sister and her husband
[12:42] <SpeedEvil> :/
[12:42] <gordonjcp> of course in that case, they must have gone round the car park plipping cars - is it going to be the Audi TT?
[12:42] <SpeedEvil> i
[12:42] <gordonjcp> no... well is it going to be that Ford Cougar? no...
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[12:43] <gordonjcp> so eventually it turned out to be the J-reg Vauxhall Nova
[12:43] <gordonjcp> which didn't work
[12:43] <SpeedEvil> most keys have some sort of badge on them
[12:43] <gordonjcp> and turned up about a mile away, locked up with the steering lock on
[12:43] <SpeedEvil> 'please steal, so I don't have to fix - bring own towtruck'
[12:43] <gordonjcp> it was in the papers
[12:44] <gordonjcp> Kate phoned them to see if anyone fancied running the story - when she got married they had wedding cakes in the shape of the Nova and the Landrover ;-)
[12:44] <gordonjcp> so they did
[12:45] <gordonjcp> and a week later when she found the car, even more papers picked up the story ;-)
[12:45] <Laurenceb> rofl
[12:45] <Laurenceb> navo cake
[12:45] <Laurenceb> *nova
[12:46] <gordonjcp> http://www.thescottishsun.co.uk/scotsol/homepage/news/article2259432.ece
[12:47] <gordonjcp> among others
[12:47] <gordonjcp> oddly enough The Sun had the most accurate coverage of it, *and* the foresight to photoshop out the number plate
[12:48] <jockc> I used to stay right next to arklay street, surprised it wasnt burn out :P
[12:50] <Laurenceb> http://www.thescottishsun.co.uk/scotsol/homepage/news/article2259432.ece
[12:51] <Laurenceb> woops
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[13:30] <gordonjcp> jockc: heh
[13:35] <SpeedEvil> jockc: where abouts are you now?
[13:35] Action: SpeedEvil is near glenrothes, fife.
[13:41] <Laurenceb> looks like a steel propane tank gives you 28% steel/LOX and alu tank gives you 19% alu/LOX. You need 27% structural mass fraction for a 2 stage LOX/parafin hybrid.
[13:42] <edmoore_> Laurenceb: you're a man possessed
[13:42] <Laurenceb> so 2 stage is doable with alu propane tanks, but you need balloon launch
[13:42] <SpeedEvil> you're assuming pressure fed?
[13:42] <Laurenceb> hehe its interesting
[13:42] <Laurenceb> yes
[13:42] <SpeedEvil> I was doing something wacky with a gas-generator driven pump
[13:42] <Laurenceb> http://www.worthingtoncylinders.com/Products/Propane/Portables/Aluminum.aspx
[13:42] <SpeedEvil> I found the A4 recently
[13:42] <SpeedEvil> Annoyingly, it details exactly - pretty much - a year or two later patent
[13:44] <Laurenceb> ~75 Kg on a balloon is a bit on the heavy side
[13:44] <SpeedEvil> pistonless pump - decompose H2O2 to push propellant out of a resovoir
[13:44] <Laurenceb> may as well launch a person
[13:44] <SpeedEvil> you're not taking the normal working pressure?
[13:44] <Laurenceb> sounds like too much to go wrong
[13:44] <Laurenceb> 500PSI
[13:44] <SpeedEvil> For rocketry use, you want to use about 20% under the burst pressure
[13:44] <Laurenceb> theres a small risk of it exploding
[13:45] <Laurenceb> burst pressure is 1200PSI
[13:45] <Laurenceb> they are rated at 350PSI
[13:45] <Laurenceb> - safety regs for propane
[13:45] <SpeedEvil> also - propane and steel tanks for normal use are _WAY_ too heavy than you really need
[13:45] <SpeedEvil> for example
[13:45] <SpeedEvil> how much pressure can 0.5mm aluminium hold?
[13:45] Action: SpeedEvil throws a can of coke at Laurenceb.
[13:46] <Laurenceb> the alu ones are considerably lighter - in fact you couldnt do 2 stage without alu
[13:46] <SpeedEvil> ~150PSI or so, mass fraction of dmn good.
[13:47] <SpeedEvil> I was - IIRC - looking between either welded thin steel, or Al with a fiberglass wrap
[13:47] <Laurenceb> propane tanks are off the shelf
[13:47] <Laurenceb> saves a ton of faff
[13:47] <SpeedEvil> yes, that's very true
[13:48] <SpeedEvil> However - making vacuum bagged glass stuff, or filliment wound isn't _too_ bad
[13:48] <SpeedEvil> I did actually consider plastic barrels.
[13:49] <SpeedEvil> Which sort-of-worked, as I wasn't going pressure fed
[13:50] <SpeedEvil> If you're not pressure fed, it relaxes lots of stuff
[13:50] <SpeedEvil> A 1m^3 60PSI tank is lots easier than 600PSI
[13:50] <SpeedEvil> but of course, it makes other things lots harder
[13:51] <SpeedEvil> If 'you' have that source of carbon fibre prepeg, that helps lots too
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[13:56] <Laurenceb> carbon fibre lox tanks are tricky
[13:56] <Laurenceb> or so I hear
[13:56] <Laurenceb> http://www.mantank.com/products/documents/DOTCatalogNo4903210_07.pdf
[13:56] <SpeedEvil> yeah - cryogens add a layer of mess
[13:57] <SpeedEvil> differential crap
[13:57] <SpeedEvil> especially if you try to make them wierd shapes.
[13:57] Action: SpeedEvil stabs lockheed martin/NASA.
[13:58] <Laurenceb> guess you could line a CF tube with insulator
[13:58] Action: Laurenceb gets back to the off the shelf CF tube idea
[13:59] <Laurenceb> unfortunatley the liner needs to hold the pressure
[14:00] <SpeedEvil> Or you pressurise the insulant with neon.
[14:00] <Laurenceb> guess you could use helium and open cell foam
[14:00] <SpeedEvil> (about the only gas with a non-sucky thermal conductivity that hasn't condensed)
[14:00] <SpeedEvil> He has nasty conductance
[14:01] <Laurenceb> hmm neon ullage...
[14:01] <Laurenceb> sounds a bit odd
[14:01] Action: SpeedEvil had a silly plan for fixing the shuttle ice problem
[14:01] <Laurenceb> open cell foam with a plastic liner
[14:01] <Laurenceb> then an outer CF tube
[14:02] <SpeedEvil> Remove the foam from most of the ET, place a tent filled with neon over the shuttle
[14:02] <Laurenceb> oh dear... where is this going
[14:02] <SpeedEvil> It actually saves quite significant mass too
[14:02] <Futurity> Hi
[14:02] <Laurenceb> I see
[14:02] <Laurenceb> actually thats quite smart
[14:03] <Laurenceb> apart from many of the problems are caused by the foam fracturing
[14:03] <Laurenceb> not ice
[14:03] <SpeedEvil> the problem is the foam comes off as it's infiltrated with ice
[14:03] <Futurity> out of interest how much pressure would a plastic bottle hold if it was surrounded by something like carbon fibre
[14:03] <SpeedEvil> or has ice form in void pockets
[14:03] <Futurity> I don't know much about this pressure stuff
[14:03] <Futurity> ;)
[14:03] <SpeedEvil> Futurity: the bottle itself - coke bottles - hold 150PSI or so
[14:03] <SpeedEvil> Futurity: normally
[14:04] <Futurity> i see
[14:04] <Futurity> and as they expand (very slightly)
[14:04] <SpeedEvil> Futurity: basically, as much as you want - it ddepends on how much CF you add
[14:04] <Futurity> surely if they were in a tight jacket, that would cope with considerably more pressure?
[14:04] <SpeedEvil> the plastic in that situation takes essentially no load - as it's so enormously less stiff than the carbon
[14:05] <Laurenceb> hmm any idea why they always use helium for pressurization?
[14:05] <Futurity> is carbon fibre gas proof
[14:05] <Futurity> i mean doesn't let gass through it?
[14:05] <Laurenceb> not very
[14:05] <SpeedEvil> Laurenceb: _reallly_ low boiling point
[14:05] <Laurenceb> it needs a liner
[14:05] <Futurity> it's not a smooth serface is it?
[14:05] <SpeedEvil> Laurenceb: low density
[14:05] <Laurenceb> yeah thats a point
[14:05] <SpeedEvil> Futurity: carbon fibre is one half
[14:05] <SpeedEvil> Futurity: the other half is the matrix round it
[14:06] <SpeedEvil> Futurity: you can have carbon fibre/lemon jelly composite - it won't work well - but you can do it :)
[14:06] <Futurity> i see
[14:06] <Futurity> out of interest, is this to contain rocket fuel inside a rocket body
[14:06] <SpeedEvil> Futurity: polyester resins are usually used for fibreglass, epoxies are common with CF, and you can even use a sort of graphite like carbon as a matrix round the fibres
[14:06] <Futurity> or for some other reason?
[14:07] <SpeedEvil> structural, really
[14:07] <Futurity> i see
[14:07] <SpeedEvil> but in many designs of rocket, you have large high-pressure tanks
[14:07] <Futurity> yes
[14:07] <SpeedEvil> which need to be really light
[14:07] <Futurity> that are structural as well as containing fuel
[14:08] <SpeedEvil> yes
[14:08] <Futurity> carbon fibre is the very thin, super strung stuff
[14:08] <Futurity> *strong
[14:08] <SpeedEvil> carbon fibre is basically ... carbon fibres
[14:08] <SpeedEvil> it's 5um or so duameter carbon fibres
[14:09] <SpeedEvil> that are put in some matrix to 'glue' them together, and get tehm to act like one nice stiff unit
[14:09] <Futurity> but i take it that it's hard to use this with epoxy and keep the body of a rocket very thin?
[14:09] <Laurenceb> SpeedEvil: you could use nitrogen
[14:09] <SpeedEvil> that's more of a manufacturability issue
[14:09] <SpeedEvil> Laurenceb: nitrogen is very heavy - and has a - comparatively - high boiling point
[14:10] <SpeedEvil> Laurenceb: at 600PSI, 1l of nitrogen will weigh about 40g.
[14:10] <Laurenceb> it wouldnt condense inside the foam
[14:10] <SpeedEvil> oh
[14:10] <Futurity> true. I think i've seen it used with vacuum envelopes to use atmospheric pressure to force the layers together?
[14:11] <SpeedEvil> Futurity: for small rockets, a huge issue is that achieving the theoretical strength of materials becomes a hideous problem
[14:11] <Futurity> i can imagine
[14:11] <Futurity> btw, is the use of Hydrogen for balloons banned these days?
[14:11] <SpeedEvil> Futurity: making a 1cm thick bit of steel/aluminium/kevlar/carbon fibre is easy
[14:12] <Futurity> i know it doesn't give much better lift than helium, but i would have thought it was a lot cheaper?
[14:12] <SpeedEvil> making a .2mm thick one on the other hand
[14:12] <Futurity> lol yes
[14:12] <Futurity> especially if it is a curved surface
[14:12] <SpeedEvil> Futurity: there are no actual regulations - as I understand - unless it's passenger carrying
[14:13] <Futurity> i see
[14:13] <Futurity> i've no idea of what these gases cost
[14:13] <SpeedEvil> most people seem to go with helium, as they are scared.
[14:13] <Futurity> i just know that it is possible to generate the hydrogen yourself
[14:13] <SpeedEvil> (or it's more easy to get approval for)
[14:13] <Futurity> yes
[14:14] <SpeedEvil> Look on youtube, and you can find what happens when hydrogen filled weather balloon is ignited
[14:14] <rjharrison> It's easier to phone boc for a cylinder of He
[14:14] <SpeedEvil> it's basically no more hazerdous than a bonfire of the same diameter that lasts .5 seconds
[14:14] <Futurity> Hi rj
[14:14] <SpeedEvil> BOC don't do he?
[14:14] <SpeedEvil> H
[14:15] <Futurity> how expensive is it to fill one of your typical balloons?
[14:15] Action: Laurenceb wonders how much neon costs
[14:15] <Laurenceb> ~£20 to 50
[14:15] <Futurity> that's not too bad
[14:15] <Futurity> i bet the balloons themselvs aren't cheap
[14:16] <SpeedEvil> 10-20 ish
[14:16] <SpeedEvil> They're really elephant condoms.
[14:17] <Futurity> lol
[14:18] <Futurity> i've see the images of the zero pressure balloons. are they cheeper to make? I take it that are better for longer flights?
[14:18] <SpeedEvil> non ZP balloons don't burst
[14:18] <SpeedEvil> latex balloons filled on the ground burst at altitude
[14:18] <SpeedEvil> err
[14:19] <SpeedEvil> ZP balloons don't burst
[14:19] <SpeedEvil> and you have to make ZP yourself.
[14:19] <Futurity> yes, i bet it takes a long time to make
[14:19] <Futurity> and very easy to damage the film
[14:20] <Futurity> i suppose with ZP it is a balancing act between the volume and lifting power at sea level, compared with the volume of the gas at high altitude
[14:20] <SpeedEvil> there are videos of asembly on youtube
[14:21] <Futurity> as in you can start loosing gas if your balloon isn't big enough
[14:21] <Futurity> i'll check them out
[14:21] <Laurenceb> hmm its hard to insulate a CF tank very well even with neon
[14:21] <Laurenceb> I guess you only really want to avoid thermal shock
[14:21] <Futurity> I'll stop asking simple questions and let you continue talking about the complex stuff :)
[14:21] <Laurenceb> heh its ok
[14:22] <SpeedEvil> cary on plz
[14:22] <SpeedEvil> you're far more likely to actually do something about what you're talking about than either of us
[14:22] <SpeedEvil> (at least in the near term)
[14:22] <Laurenceb> lol
[14:22] <Futurity> lol
[14:22] <Futurity> i take it you are looking to build a rocket to launch from ground level?
[14:23] <Laurenceb> no, from a balloon
[14:23] <Futurity> oh
[14:23] <Futurity> as part of the Spaceflight project?
[14:23] <Laurenceb> not really
[14:23] <Laurenceb> just to see if it can be done
[14:23] <Futurity> oh seperately
[14:23] <Futurity> cool
[14:24] <Futurity> impressed that they hope to reach 150KM
[14:24] <Futurity> I was thinking how people may pay money to have part of them flown to that altitude
[14:24] <Futurity> only a few cells
[14:24] <Laurenceb> I'm looking at orbit
[14:24] <Futurity> but how good would it be to say that your DNS has been in space
[14:25] <Futurity> orbit would be amazing
[14:25] <Futurity> but i think a near impossible task for a small team
[14:25] <Futurity> just due to expense
[14:25] <Futurity> but again, i'm not familiar with any of the cost, just a gut feel
[14:26] <SpeedEvil> I'm wanting to make a 1Kg orbiting rocket, for about 5-10K launched from the ground
[14:26] <Futurity> wow
[14:26] <Futurity> 1kg after all fuel burnt?
[14:26] <SpeedEvil> 1Kg payload
[14:26] <Futurity> that's a serioud wieght
[14:26] <SpeedEvil> about a ton launch weight, 4 stage
[14:26] <Futurity> serious weight
[14:27] <Futurity> lol
[14:27] <Futurity> sorry
[14:27] <Futurity> just thinking of the spaceflight stuff, no insurance and wrapped in foam padding
[14:27] <Futurity> wondering if you'd also use foam on the rocket to limit liability?
[14:28] <SpeedEvil> doesn't really help
[14:28] <Futurity> a ton rocket would be seriously amazing. you'd get in all the papers with something like that
[14:28] <Laurenceb> lol
[14:28] <SpeedEvil> the fun part isn't it dropping on someone, but exploding
[14:28] <SpeedEvil> or hitting them at mach 3
[14:28] <Laurenceb> foam at 8Km/s doesnt help
[14:28] <SpeedEvil> which needs an impractical amount of foam
[14:28] <Futurity> yep
[14:29] <Laurenceb> it seems the main problem with CF is thermal shock and feed throughs
[14:29] <Futurity> and i take it this 8km/s will be at a fairly low altitude?
[14:29] <Laurenceb> 200Km
[14:31] <Laurenceb> pouring LOX onto CF isnt going to be good
[14:31] <Laurenceb> but a foam lined tank might be ok
[14:31] <Futurity> i take it that the further up you go, you need less speed to orbit? or is it the same speed, just that the orbit is longer?
[14:31] <SpeedEvil> it's slower
[14:32] <SpeedEvil> but - not appreciably slower for teh first few hundred Km
[14:32] <SpeedEvil> you need to be over 150Km or so to get more than one orbit due to drag
[14:32] <Futurity> i best finish this database replicator
[14:32] <Futurity> otherwise I'll get shot ;)
[14:32] <Futurity> i'll drop back when i can
[14:33] <Laurenceb> cya
[14:33] <Futurity> ttfn
[14:33] <Laurenceb> hmm if you has a CF tube with alu bulkheads they are likely to come detatched if epoxied on
[14:34] <Laurenceb> maybe it would work with O rings and bolts
[14:34] <SpeedEvil> CF bulkheads,
[14:34] <SpeedEvil> on inflatable formers
[14:36] <Laurenceb> still a material compatibility issue
[14:36] <Laurenceb> - thermal expansion
[14:41] <Laurenceb> if the rocket is encased inside a large block of foam for launch, then vented to stop the tank exploding during ascent, then just before launch vent to ~5millibar, then repressurise with helium from a aircraft cylinder onboard the balloon
[14:43] <SpeedEvil> best of course if you've got some LOX to top-off with
[14:44] <Laurenceb> well you want some space at the top of thwe tank
[14:44] <SpeedEvil> yeah
[14:45] <Laurenceb> well - you need some sort of tank liner, so you could use open cell foam
[14:46] <Laurenceb> and have that as a helium store
[14:47] <SpeedEvil> hmm
[14:47] <Laurenceb> thermal shock may damage the CF if you just pour in LOX
[14:48] <SpeedEvil> Tank made of thick Al foil, which crushes as the He comes out of the foam
[14:48] <Laurenceb> easier to stick a pipe out onto the balloon bourne launch platform
[14:49] <Laurenceb> tho kevlar helium bottles are about $500 each
[14:50] <Laurenceb> guess you trade a lot to go wrong on the ground with a bit to go wrong in the air
[14:50] <Laurenceb> setting up the HE filled foam to the correct pressure would be a pain
[14:50] <SpeedEvil> and of course, as ever, payload fraction
[14:50] <SpeedEvil> yes
[14:51] <Laurenceb> as would the cryo liner
[14:51] <Laurenceb> - deformable cryo liner
[14:53] <Laurenceb> nozzle injection is a pain with LOX
[14:56] <Laurenceb> you dont want to be injecting LOX into the graphite nozzel
[14:56] <SpeedEvil> yeah
[14:57] <SpeedEvil> it's a hybrid too!
[14:58] <Laurenceb> wax
[14:58] <Laurenceb> - ikea
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[15:02] <rjharrison> Hi jcoxon
[15:02] <jcoxon> hey rjharrison
[15:02] <rjharrison> cygwin is proving to be a real bugger
[15:02] <jcoxon> oh
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[15:14] <Laurenceb> SpeedEvil: with LOX/wax you need a ~92% mass fraction for SSTO, CF gets you to approx 1% for tankage
[15:17] <SpeedEvil> IMO - SSTO - run
[15:18] <Laurenceb> guess a balloon counts as a stage
[15:22] <SpeedEvil> SSTO is almost insanely hard for amaturs
[15:22] <SpeedEvil> at least not stupidly funded
[15:22] <SpeedEvil> though balloon launch admittedly helps
[15:22] <Laurenceb> http://hardyadvancedcomposites.org/tube_sales.aspx
[15:22] <Laurenceb> hmm one of those would be perfect
[15:23] <Laurenceb> not the best CF, but still an order of magnitude better than aluminium
[15:35] <Laurenceb> ~4% mass fraction for the CF tube with a 50% safety margin
[15:37] <SpeedEvil> you're not asuming that the CF meets the spec outlayed on that page?
[15:37] <SpeedEvil> that sort of firm will typically only know the material specs
[15:37] <SpeedEvil> they will not have actually tested the finished product
[15:37] <SpeedEvil> actuall
[15:37] <SpeedEvil> prepeg is hard to screw up much
[15:38] <Laurenceb> I've seen higher spec stuff than that
[15:39] <Laurenceb> up to 4000Mpa or 5000
[15:39] <Laurenceb> and slightly higher density
[15:39] <SpeedEvil> I was doing numbers earlier for windows :)
[15:40] <SpeedEvil> CF reinforcement to make the glass less stressed
[15:40] <SpeedEvil> and allow thinner wooden sections
[15:40] <SpeedEvil> worked out about 20-30 quid a window - to shave off 5mm or so of wood and keep same stiffness
[15:50] <Laurenceb> uPVC windows really suck
[15:51] <SpeedEvil> Clearly CF windows are better!
[15:51] <SpeedEvil> :)
[15:52] <SpeedEvil> Initial assumption was that it'd be so stiff, I would largely completely offload the glass
[15:52] <SpeedEvil> But, I diddn't realise that fiberglass is only about twice as stiff as wood
[15:53] <SpeedEvil> Wood is actually pretty much similar in stiffness
[15:53] <SpeedEvil> and carbon - though great - basically needs to be fairly large slabs to take teh load
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[16:07] <Laurenceb> hmm a 85Kg 3m long 20cm diameter SSTO would work
[16:07] <Laurenceb> about 500grams payload
[16:07] <Laurenceb> nozzle has to weight < 1.2Kg tho
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[16:08] <SpeedEvil> the fun part is if you can cheat and reuse payload weight
[16:08] <SpeedEvil> for example - payload battery powers launcher
[16:09] <Laurenceb> yes
[16:09] <SpeedEvil> and payload does all the GNC
[16:09] <Laurenceb> 3Kg CF tube, 1.2Kg nozzle, 1Kg bulkheads/injector/pipes, 0.8Kg tronics
[16:10] <Laurenceb> gives 6Kg total
[16:10] <Laurenceb> and tube holds ~80Kg of propellant
[16:10] <SpeedEvil> 15cm dia?
[16:10] <Laurenceb> 20
[16:11] <Laurenceb> 2.5 to 3m long
[16:11] <Laurenceb> - CF pressure vessel is 2.5
[16:12] <SpeedEvil> what's the remaining atmosphere along the trajectory in a tube 20cm dia weigh?
[16:12] <Laurenceb> a lot
[16:12] <Laurenceb> you have to balloon launch
[16:12] <SpeedEvil> at 20km, I mean
[16:13] <Laurenceb> at 31Km its almost exactly 3kg
[16:18] <Laurenceb> armadillo aerospace used some CF wrapped graphite nozzels
[16:22] <Laurenceb> but attatchuing that to the main tube would be tricky
[16:52] <Laurenceb> cya
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[17:42] <edmoore> libpn-bloody-g.h
[17:42] <edmoore> gah
[17:42] <edmoore> afternoon all
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[20:10] <rjharrison> #cygwin
[20:19] <sbasuita> wut
[20:23] <natrium42> eww
[20:23] <natrium42> msys ftw
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[21:52] <jcoxon> hey edmoore
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[21:53] <jcoxon> hehe
[21:54] <stilldavid> or not, eh?
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[22:03] <jcoxon> of well
[22:03] <jcoxon> oh*
[22:03] <jcoxon> :-)
[22:03] <jcoxon> ping G8KHW_Away, when you get back
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[22:21] <G8KHW_Away> /nick G8KHW
[22:21] <G8KHW_Away> \nick G8KHW
[22:21] Nick change: G8KHW_Away -> G8KHW
[22:21] <G8KHW> thats better
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[22:48] <jcoxon> ping natrium42
[22:50] <akawaka> host not found
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[22:51] <jcoxon> akawaka, really?
[22:55] <natrium42> hey jcoxon
[22:59] <jcoxon> hey can i get you to test the client on osx?
[22:59] <jcoxon> as we might have a launch on sunday
[23:00] <natrium42> yah, ok
[23:00] <natrium42> let me reboot
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[23:03] <natrium42> ok, osx here :)
[23:04] <jcoxon> okay, 30 secs just compiling new version
[23:04] <natrium42> kk
[23:08] <jcoxon> natrium42,
[23:08] <jcoxon> http://pegasus4.no-ip.org/~jamescoxon/fldigi-3.11.4r38.dmg
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[23:14] <natrium42> ok, it's starting up
[23:14] <jcoxon> or http://dl-fldigi.googlecode.com/files/fldigi-3.11.4r38.dmg
[23:14] <jcoxon> oh okay
[23:14] <natrium42> seems to work
[23:14] <jcoxon> great
[23:15] <jcoxon> can you enter your operator data to check it posts to the server
[23:15] <jcoxon> oh got it
[23:16] <jcoxon> great, that tmakes my life easier
[23:17] <jcoxon> thanks natrium42
[23:18] <natrium42> sure thing
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[23:21] <jcoxon> night all
[23:21] <natrium42> nite jcoxon
[23:22] <jcoxon> night natrium42
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[00:00] --- Sat May 23 2009