ZeissIkon on January 20, 2012, 11:28:40 pm
I presume most of our readers are aware that you can't actually power a rocket with only magnesium and aluminum.  Then again, I suppose our author and editors don't want to tell terrorists what they already know.  Come on, guys, information on rocket fuels has been available to the general public since the 1950s ("Rocket Manual for Amateurs", published in connection with a rocket club at Fort Sill, Oklahoma, had plans for rockets ranging from a CO2 bulb inside a cigar tube to one similar in size to Leon's Tasman Sea distaster-in-the-making, powered by a pretty hazardous, inefficient, but very, very fast-burning propellant mix; it came out in, as I recall, 1957).  FWIW, an early 21st century amateur rocket the size of Leon's, built with the common "80% motor" proportion, is probably capable of busting 6 km altitude and Mach 2 -- and impacting at close to Mach 1 when it finally comes down, if the recovery system fails.

Apollo-Soyuz on January 21, 2012, 05:01:56 am
Leon's Rocket was probably was inspired by this

It looks like they launched from international waters just so they had less red tape to deal with.

Apollo-Soyuz on January 21, 2012, 05:14:55 am
This video (different group) is also made of win

http://www.youtube.com/watch?v=5HTwbpjBUOk


SandySandfort on January 21, 2012, 07:25:02 am
I presume most of our readers are aware that you can't actually power a rocket with only magnesium and aluminum.

The word "only" does not appear in the strip. If I wrote that a cake was made with sugar and eggs, I wouldn't expect anyone to think that the cake only had sugar and eggs. You cannot power a car with only gasoline. Cars and rockets need oxidizers, but guess what, the details of how the rocket works are not at all germane to the story of Leon's desire to take Man into space. Please feel free, however, to mentally add whatever other rocket fuel ingredients you want. Heck you could even add sugar (though eggs might be a bit much).  ;D

Then again, I suppose our author and editors don't want to tell terrorists what they already know. 

Don't be silly.

wdg3rd on January 21, 2012, 08:57:44 pm

The word "only" does not appear in the strip. If I wrote that a cake was made with sugar and eggs, I wouldn't expect anyone to think that the cake only had sugar and eggs. You cannot power a car with only gasoline. Cars and rockets need oxidizers, but guess what, the details of how the rocket works are not at all germane to the story of Leon's desire to take Man into space. Please feel free, however, to mentally add whatever other rocket fuel ingredients you want. Heck you could even add sugar (though eggs might be a bit much).  ;D


Actually, sugar and potassium nitrate made quite adequate solid rocket fuel back when I was 12 or 13.
Ward Griffiths        wdg3rd@aol.com

Men will never be free until the last king is strangled with the entrails of the last priest.  --  Denis Diderot

ZeissIkon on January 23, 2012, 04:12:05 pm

The word "only" does not appear in the strip. If I wrote that a cake was made with sugar and eggs, I wouldn't expect anyone to think that the cake only had sugar and eggs. You cannot power a car with only gasoline. Cars and rockets need oxidizers, but guess what, the details of how the rocket works are not at all germane to the story of Leon's desire to take Man into space. Please feel free, however, to mentally add whatever other rocket fuel ingredients you want. Heck you could even add sugar (though eggs might be a bit much).  ;D


Actually, sugar and potassium nitrate made quite adequate solid rocket fuel back when I was 12 or 13.


Many different kinds of sugars and several different oxidizers still make pretty good amateur propellants, though the canonical mixing method (effectively making caramel spiked with the oxidizer) is a bit hazardous.  There are many good reasons most adult amateurs, at least those with a budget, gravitate toward "composite" propellant using synthetic rubber and a perchlorate oxidizer, sometimes with a metal added to increase burn rate, temperature, and thrust.

Okay, Sandy, you're right -- you didn't say "only", but most folks who build composite rocket motors (the ones that use similar chemistry to the Space Shuttle's SRBs) call the synthetic rubber binder the "fuel" (since these motors work well with no added metal at all), and if they add aluminum, refer to it as a "booster" or "performance enhancer" rather than considering it the primary fuel (though chemically, it's correct to call the SRB's aluminum fueled, since the majority of the energy comes from combustion of the metal).  Regardless, as you note, grossly non-germaine to the story (which I presume has much more to do with where the rocket went than what it was made of).

I note, for the YouTube link above, that I underestimated the potential performance of a rocket in this size range -- Mach 3, and more like 40 km than 6, though one might reasonably assume a rocket that size built by school kids (without the multi-thousand-dollar budget of an adult amateur team) would perform less spectacularly.

Corwin on January 25, 2012, 09:19:06 am
It has been a good long while since I posted, but this topic is hitting close to home, since I am one of a good number of amateur rocketeers with a goal strikingly similar to Leon.  That is, we are working for cheap access to space.  The two groups I have involvement in who are working toward that goal from similar but still unique directions are:

The Sugar Shot to space - www.sugarshot.org

and

The Iowa Amateur Rocketry Group (IARG) - http://www.thefintels.com/aer/rocketindex.htm

The current base goal of each group is to launch a rocket powered by an inexpensive, easily produced propellant beyond the threshold of space (60 Mi. or 100 km), and recover it, using this (results, obtained telemetry, gained experience) as a stepping stone to bigger and better things.  As Sandy has set forth in EFT, it is my belief that the first true commercial exploitation of space will be the asteroid belt.  Further, I believe it falls to free sovereign individuals to achieve this goal, since the political motives of national governments are incompatible with moving this forward.  Governments want to control resources, and to keep control of those resources out of the private sector.  This must not be allowed to stand.  My soapbox is small, but I like the view from up here. :)

ZeissIkon on January 26, 2012, 03:36:41 pm
Leon's big rockets, now, look a great deal like the Space-X Falcon series.  Then again, they pretty well have to, for the same reasons jet fighters all looked a lot alike in the 1970s and 1980s (even American vs. Soviet birds): at a certain level of development, there are a limited number of configurations that will give optimum performance.

sams on January 27, 2012, 06:06:55 am
Leon's big rockets, now, look a great deal like the Space-X Falcon series.  Then again, they pretty well have to, for the same reasons jet fighters all looked a lot alike in the 1970s and 1980s (even American vs. Soviet birds): at a certain level of development, there are a limited number of configurations that will give optimum performance.

You are right, this is one of the things you learn in Engineering : Design tend to converge to both Physical and technical limits.

If there was ever a form of energy 100x cheaper than today, we would have Star Warsy looking ships, till then we are going to have rockets.

Tucci78 on January 27, 2012, 10:07:01 am
Leon's big rockets, now, look a great deal like the Space-X Falcon series.  Then again, they pretty well have to, for the same reasons jet fighters all looked a lot alike in the 1970s and 1980s (even American vs. Soviet birds): at a certain level of development, there are a limited number of configurations that will give optimum performance.

The writers of currently popular "technothriller" military fiction (a specfic subgenre that the mundanes have from time to time embraced for more than a century, and which they glommed onto again when the U.S. Naval Institute published Tom Clancy's novel The Hunt for Red October in 1984) have discussed this phenomenon speculatively, particularly as a problem in visual recognition during combat.

In Clancy's later (1986) novel Red Storm Rising, mention is made of the fact that the Mikoyan MiG-29 (NATO code name Fulcrum) "...was a virtual twin to..." the American F/A-18 Hornet insofar as visual configuration is considered.  Clancy described the fictional situation:
Quote
The resulting air battle was a masterpiece of confusion. The two aircraft would have been hard to distinguish sitting side by side on the ground. At six hundred knots, in the middle of battle, the task was almost impossible, and the Americans, with their greater numbers, had to hold fire until they were sure of their targets. The Russians knew what they were attacking, but they too shrank from shooting with abandon at a target that looked too much like a comrade's aircraft. The result was a swarming mix of fighters closing to a range too short for missiles, as pilots sought positive target identification, an anachronistic gun duel punctuated by surface-to-air missiles from the two surviving Russian launchers. Controllers on the American aircraft and the Russian ground station never had a chance to direct matters. It was entirely in the hands of the pilots. The fighters went to afterburner and swept into punishing high-g turns while heads swiveled and eyes squinted at familiar shapes while trying to decide if the paint scheme was friendly or not. That part of the task was fairly even. The American planes were haze-gray and harder to spot, allowing easier target identification at long range than at short. Two Hornets died first, followed by a MiG. Then another MiG fell to cannon fire, and a Hornet to a snap-shot missile. An errant SAM exploded a MiG and a Hornet together.

Since the subsidence of the Soviet Empire, no such big "furball" air-to-air combats have occurred.  American Imperial air strength is such that no contending nation has yet been able to present more than token resistance, relying instead upon anti-aircraft artillery (AAA) and surface-to-air missile (SAM) defenses, their offensive measures restricted to bombardment missiles of varying ranges and targeting sophistication.

But the potential for extremely confused air combat situations is certainly enhanced by the fact that "...at a certain level of development, there are a limited number of configurations that will give optimum performance."
"I is a great believer in peaceful settlements," Jik-jik assured him. "Ain't nobody as peaceful as a dead trouble-maker."
-- Keith Laumer, Retief's War (1966)

ZeissIkon on January 27, 2012, 07:13:36 pm
If there was ever a form of energy 100x cheaper than today, we would have Star Warsy looking ships, till then we are going to have rockets.

I wouldn't count on that, at least in vehicles intended to operate at a profit.  If energy is essentially free (say, cheap fusion generators and/or thrusters that can operate on very impure hydrogen feedstock, such as water, methane, gas giant atmosphere, etc.), the cost of construction and operating life of the ship will determine its profitability -- and they'll all wind up spherical, or as nearly so as possible after modifications to avoid undue stress when entering atmosphere.  Least material cost per cargo mass.

Killydd on January 30, 2012, 12:41:46 pm
If there was ever a form of energy 100x cheaper than today, we would have Star Warsy looking ships, till then we are going to have rockets.

I wouldn't count on that, at least in vehicles intended to operate at a profit.  If energy is essentially free (say, cheap fusion generators and/or thrusters that can operate on very impure hydrogen feedstock, such as water, methane, gas giant atmosphere, etc.), the cost of construction and operating life of the ship will determine its profitability -- and they'll all wind up spherical, or as nearly so as possible after modifications to avoid undue stress when entering atmosphere.  Least material cost per cargo mass.

David Drake did propose a modification of this for military vessels:  The cylinder.  This allows such a ship to reduce it's target size along one axis while bringing a larger surface area to bear for gun  emplacements and other offense. 

Personally, for cargo ships I think the most likely is some skeletal frame to which some variety of intermodal containers will be attached, with the entire container then ferried down from orbit by an atmospheric re-entry craft.  Of  course for an airless body like Ceres or an orbital space station, that might not be much more than an engine and docking clamps.  Individual containers could be pressurized, the cargo's radiation shielding could vary depending on need and cost, whole containers could just be locked at one end and unlocked at the other to help with the paperwork. 

Andreas on February 28, 2012, 02:36:15 pm
Leon's big rockets, now, look a great deal like the Space-X Falcon series.  Then again, they pretty well have to, for the same reasons jet fighters all looked a lot alike in the 1970s and 1980s (even American vs. Soviet birds): at a certain level of development, there are a limited number of configurations that will give optimum performance.

The writers of currently popular "technothriller" military fiction (a specfic subgenre that the mundanes have from time to time embraced for more than a century, and which they glommed onto again when the U.S. Naval Institute published Tom Clancy's novel The Hunt for Red October in 1984) have discussed this phenomenon speculatively, particularly as a problem in visual recognition during combat.

In Clancy's later (1986) novel Red Storm Rising, mention is made of the fact that the Mikoyan MiG-29 (NATO code name Fulcrum) "...was a virtual twin to..." the American F/A-18 Hornet insofar as visual configuration is considered.  Clancy described the fictional situation:
Quote
The resulting air battle was a masterpiece of confusion. The two aircraft would have been hard to distinguish sitting side by side on the ground. At six hundred knots, in the middle of battle, the task was almost impossible, and the Americans, with their greater numbers, had to hold fire until they were sure of their targets. The Russians knew what they were attacking, but they too shrank from shooting with abandon at a target that looked too much like a comrade's aircraft. The result was a swarming mix of fighters closing to a range too short for missiles, as pilots sought positive target identification, an anachronistic gun duel punctuated by surface-to-air missiles from the two surviving Russian launchers. Controllers on the American aircraft and the Russian ground station never had a chance to direct matters. It was entirely in the hands of the pilots. The fighters went to afterburner and swept into punishing high-g turns while heads swiveled and eyes squinted at familiar shapes while trying to decide if the paint scheme was friendly or not. That part of the task was fairly even. The American planes were haze-gray and harder to spot, allowing easier target identification at long range than at short. Two Hornets died first, followed by a MiG. Then another MiG fell to cannon fire, and a Hornet to a snap-shot missile. An errant SAM exploded a MiG and a Hornet together.

Since the subsidence of the Soviet Empire, no such big "furball" air-to-air combats have occurred.  American Imperial air strength is such that no contending nation has yet been able to present more than token resistance, relying instead upon anti-aircraft artillery (AAA) and surface-to-air missile (SAM) defenses, their offensive measures restricted to bombardment missiles of varying ranges and targeting sophistication.

But the potential for extremely confused air combat situations is certainly enhanced by the fact that "...at a certain level of development, there are a limited number of configurations that will give optimum performance."


Then again, vehicle identification is a primary military skill.
A friend of a friend was leading a Danish Leopard I tank column somewhere in Yugoslavia, when it was hot there.
He was very displeased to overhear a US apache pilot chatter about sighting a column of Serbian T-55s in the area... luckily the mandate at the time did not allow US Apache pilots to open fire on T-55 columns, or the mistake would have cost Danish lives.
Also luckily, the US forces adhered to the mandate more strictly than the Danes. The Danish Leopard 1s were the only tanks in the aid escort forces, and the danish brass had decided that the serb hoodlums could do with an object lesson in keeping their grandstanding to a minimum. So the danish tanks had orders to respond with their main guns whenever one of these yahoo groups thought it'd be fun to plink at an aid column with a machine gun. Something other forces had to just put up with.

Also used the main guns to air up unauthorized road blocks (giving fair warning, i.e. count to ten).

Funnily enough, nobody ever bothered to challenge this reading of the mandate ;D

 

anything