We often look up at the clouds and wonder exactly how high they are. Meterologists have ranging equipment but it's expensive and not particualrly portable.
For the curious home meteorologist, we propose a type of firework rocket which leaves a smoke trail. Externally, it is identical to a normal firework. You stick the rocket in a piece of tube as normal and light it.
The difference is that the propellant has coloured smoke composition mixed in, and it's pressed in layers. Each layer burns for a calculated time, based on the velocity of the rocket at that point in its flight (they accelerate as they get higher, it's a second-order differential equation). This means that the rocket's smoke trail changes colour (red/white/blue/yellow/green) at 50 or 100 metre intervals as it climbs. When the rocket reaches the cloud (and disappears), all you do is count the "blocks" of smoke and multiply the total by X where X is the "block height" for that type of rocket.
Then you will need to move somewhere else quite quicky, because an angry person who has just had a spent rocket come hurtling out of the sky onto their property can clearly see the neat, coloured smoke trail leading back to the place it was launched from.-- 8th of 7, Aug 22 2002 Laser Range Finder http://www.nightvis...om/range_finder.htmI think you'll find this more economical in the long term. Good to 5,000 feet (I dunno, how high do clouds go?). Not that shooting colored rockets into the sky isn't a worthwhile pasttime. [DrCurry, Aug 22 2002, last modified Oct 21 2004] A purpose-built version. http://www.qualimet...l/cloud_height.html"measures cloud height up to 25,000 feet by calculating the return time of laser light pulses" [angel, Aug 23 2002, last modified Oct 21 2004] Puff Matrix Printer referenc http://www.halfbake..._20Weather_20ReportMentioned in an annotation. [half, Aug 26 2002, last modified Oct 05 2004] Virtual fireworks http://www1.jawink....ava/jhanabi2e_b.htmturn up the sound and do your own [FarmerJohn, Aug 26 2002, last modified Oct 21 2004] Yet *another* device to tape a cat to...-- Mr Burns, Aug 22 2002 ("..and, I almost thought I saw a black speck falling from the cloud going 'meeeeeyoooowwwww........', but I think that was just my imagination..")-- Mr Burns, Aug 22 2002 It was just my imagination-- Mr Burns, Aug 22 2002 Rocket = Croissant.-- dag, Aug 22 2002 you'd have to compensate for the weight of the cat (and probably some drag if it was a long hair) otherwise your measurements will be off.-- rbl, Aug 22 2002 An extension to pneumatic hamster tubes...I like it, I like it...-- BinaryCookies, Aug 22 2002 UnaBubba, your description is absolutley uncanny .... have you been following us around ? Even down to the combat pants with bulging pockets ....... we can't believe you have worked out all that just by deduction ....-- 8th of 7, Aug 23 2002 That fails to explain your apparent familiarity with his inner thigh.-- angel, Aug 23 2002 Nice one 8th, I'd also like a rainbow rocket that makes a pretty parabola in parallel colors. Very funny Una; you had me in more stitches.-- FarmerJohn, Aug 23 2002 Angel: That's between us & UnaBubba, Ok ?
FarmerJohn: The parabola with serial colours is easy. Parallel smoke trails would be more difficult but we will consider the request.-- 8th of 7, Aug 23 2002 Instead of one rocket which makes the whole rainbow, how about multiple rockets (each a different color) mounted together side-by-side. Maybe leave 12 inch gaps between rockets so the colors don't mix as much. The trick is to get the red rocket to have just slightly more thrust than the purple rocket so that the cluster follows a graceful arc around the z axis while under thrust. Meanwhile, stabilizing fins will attempt to constrain the path of the rocket to the x-y plane.
The hardest part of the whole thing is getting the thrusts balanced *just right* to make a predictable arc. From what I understand about solid fuel rockets, burn rates are tough (impossible?) to regulate. They tend to vary during the burn, and are affected by the age and storage conditions of the fuel. Even two identical rockets produced at the same time and stored in identical conditions can exhibit significant (for this application, at least) differences in burn profiles.-- BigBrother, Aug 24 2002 If you plan on sending a rocket up a few miles, you might want to check with the FAA first.-- RayfordSteele, Aug 25 2002 How about luanching 7 at the same time at slightly different angles and creating a rainbow. Go to the other side of the rainbow and wala, say hello to the pot-o-gold!-- BrainFreeze, Aug 26 2002 This is starting to sound like a job for an onboard altimeter and the "Puff Matrix Printer" (color version).-- half, Aug 26 2002 "wala."
Got to love that variant. At least it's not "viola."-- bristolz, Aug 26 2002 Get a bunch of them, turn them sideways (horizontal) and shoot them off when there is turbulence at a parachuting dropzone (while the parachutists are still at sufficient height not to be hit of course). Mix parrafin wax in with the propellant so the smoke stays around a little longer, a skywriters trick, and as the skydivers decend for final approach, they can see where the eddys are and thus avoid them.
ty6-- ty6, Aug 26 2002 Adapt for night use with copper sulfate mixed in at intervals such that the rocket flame shoots out blue jets every 50 feet.-- waugsqueke, Aug 26 2002 Nice idea. Shouldn't be too difficult to do I suppose. I mean, it's not rocket science. Oh, it is. Sorry.-- sild, Sep 05 2002 random, halfbakery