Are you actually a rocket geek - or did you just roll that name randomly? Because an actual rocket geek would know how long Alan Bond has been pushing this concept.
I am well aware of how long the concept has been pushed - it makes me realise how long I've been in this game. I know Alan Bond well (in fact I work for him), and I know his co-designer on the previous concept HOTOL well too (Dr Bob Parkinson). I also know, that when they have to battle against entrenched, sclerotic viewpoints of people such as your good self, it can take a long time for development to come to fruition.
What about the tested stuff? That's like having a tested transistor, a tested capacitor, a working prototype of a voltmeter, a well polished stone knife, a properly prepared bearskin - and announcing that you are ready to use them to build a supercomputer. They're virtually meaningless.
And by that, you demonstrate how little you understand of the subject in question, sorry. Your argument is itself meaningless. The various technologies are developed to considerably more than merely component level, and I would hope you are not stupid enough to think otherwise, but are trying to illicit a response. The key is take the various technologies to higher Technology Readiness Levels. Go look up what that means if you are not sure.
Anyone who works around engineering, or who has a working knowledge of engineering, knows the real test is an integrated system. Something Reaction Engines doesn't even have the data to rough out a design before, yet alone build.
Again, that just belies your ignorance of both the process, and in this particular case, the hardware developed. You may benefit from reading the details on their website, as opposed to simply using it as an opportunity to indulge in your love of bashing - that way, you might (a) learn something, and (b) understand why the project is broken down into the distinct areas it is. Yes, I admit I am a physicist who works in engineering, as opposed to an engineer who works in engineering, if that is something you wish to use against me too.
My comments? They aren't negative - they're factual. They only seem negative and in need of fact checking because most self proclaimed rocket fanboys are like you, completely and utterly ignorant.
Actually, your comments are most certainly not factual, because if you had read the information first, and had understood anything of what is written on the project, you would understand how lacking in clues you are.
If by rocket fanboys and ignorance, you mean degrees in physics, many years of experience of working on developing rocket propulsion, genuine contributions to numerous peer reviewed rocket propulsion papers, and well used copies of rocket propulsion books such as Sutton, Huzel and Huang, and Humble and Larson which are battered because I've had cause to use them out at test sites doing real rocket propulsion testing, then I suppose I am guilty.
So come on Mr Lyons, what is your technical background? I'm sure since you are so able to cast aspersions on so many rocket concepts, that you must have an exemplary background yourself.
Do you have evidence of your assertion regarding funding?
As for the "nothing to show for it but ever spiffier computer graphics", what about the currently built heat exchanger module, the tested heat exchanger, the tested rocket engines, the tested modified jet engine being used to test the precooler, the experimental turbine, the wind tunnel to test frost formation with the hydrogen in the heat exchanger, and a host of other hardware that has been built to test various aspects of the system? Hardly just computer graphics are they?
Note, this time, I must declare an interest here. I work for Reaction Engines on the ED nozzled rocket engine test programme, so I do know what hardware exists, and in fact the reason I am late replying to this thread is due to being at static test firings this week.
Mr Lyons, do you ever check your facts before your usual negative comments on various rocketry ventures around the world?
I can understand where you are coming from completely. The task is certainly not easy, but we do believe it is achievable, and as has happened until now at Reaction Engines, the key is incremental steps towards the eventual capability.
Rocket engines do take a while to develop yes, but a deeply cooled air breathing rocket engine is in some regards less of a big deal than designs where they use a jet engine, a ramjet, a scramjet and a rocket to get into orbit. Yes, there are some elements of it that are fairly complex, but other elements of it that are more straightforward too.
Although the website lists the main projects, there are a lot of intermediate sub projects along the way that have been achieved or are in process at the moment, and as these come together, the more of that capability will be realised. We will do this, because we genuinely believe it is achieveable, we are too stubborn not to, and we owe it to those on HOTOL, Black Arrow and Blue Streak who blazed the trail. Besides which, I'll be out of a job if there isn't something shiny flying in a while;-)
Hmmm, the problem I was thinking of was in pure vacuum. Does the pintle (adjustable central obstruction in the nozzle)
Yes, you'll be pleased to know, I know what the pintle is, I have had to extract it from the motor several times:-) Not straight after testing you'll understand:-)
improve performance in vacuum?
Compared to a bell nozzle, yes, since it is operating at optimum efficiency throughout the thrust regime.
Seems to me that if you wanted almost perfect ISP, you still need a high expansion bell on your nozzle.
Absolutely, you're spot on:-) And in fact, the ED nozzle does have a very large area ratio. Even with the large area ratio, the performance gains compared to a bell nozzle should be greater than any mass hits you take by having a large area ratio nozzle in the ED. In terms of how great, that's what the ED rocket test programme that Reaction Engines is carrying out is designed to find out.
1) The graphics were produced a fair while ago. I daresay they could be improved nowadays. Much of the design work is in Solid Works, so I imagine that could be skinned and modeled accordingly.
2) Reaction Engines is focused on trying to develop an SSTO spaceplane, not a Hollywood movie. If the money was available, yes, I'm sure the graphics could be souped up, but when the budget choice is graphics or components for a rocket engine say, guess what wins in a rocket related company that is focused on developing the hardware?
Personally, I would rather trust a company that bring real hardware that has been tested to the table than a company that just has a bunch of gorgeous CG images and PowerPoint slides.
Actually not. Venturestar was a pure rocket SSTO, as opposed to an air breathing rocket SSTO. Big difference. Because it was reliant solely on pure rocket propulsion, the structural mass required materials that were very light, and one of the reasons it wasn't continued was problems with the composite non cylindrical liquid hydrogen tank, which was a major show stopper.
Skylon gains significantly by being able to use an engine that air breaths to Mach 5.5 before transitioning to pure rocket propulsion.
Thanks for replying... I think some people forget just how complicated (and time-consuming) it is to design a vehicle for space travel when you don't have billions of dollars in your budget.
My pleasure. I'm sat here working on calculations connected with the ED nozzle this afternoon (the rocket side of the engine is the part I am lucky enough to work on), and thought it made sense to reply to some of the comments where I could.
As you can imagine, there is a lot more going on behind the scenes than is indicated on the website. The problem is, we are rocket people, not PR people, so getting the word out doesn't come naturally, and we spend the vast majority of our time working on the technical aspects:-)
We also have probably an inefficient nozzle design with a tradeoff between greater bell size (and efficiency in vacuum) and lower air drag.
That's why we are developing the ED nozzle:-)
The ED nozzle is a very efficient nozzle design and provides altitude compensation across the thrust operation range. Part of the engine development at the moment is concerned with development of the ED nozzle for this purpose.
The precooler tests were run separate to the thrust tests. The thrust tests were related to the ED nozzle work.
As for the reliability, well when I wrote the test plan for the ED nozzle test engine, I can assure you, that reliability was very much part of the plan.
As for you not seeing any prototype being tested, note the photograph of a rocket shaped object with hot flame coming out of it in the News section?
I'm sorry the photograph isn't any better, but none of us were prepared to step outside the bunker during the hot firings. I'm working on improving the photos taken during test runs.
> They just totally underestimated how difficult
> it is to design a workable scramjet system.
No they didn't. You may wish to research HOTOL a bit more. It didn't use a scramjet. Not only do I know the designer of the engine of HOTOL, I am working with him on a UK rocket engine as part of the successor to HOTOL, namely SKYLON.
Scramjets are unlikely to be the answer. The US seems fixated on them, but that doesn't mean they are the most effective solution.
Also the comment regarding the maintaining of the monopoly for US launch companies at that time isn't a million miles away either. Read up on the politics, talk to politicians of that time, and you'll find the political dimension based on being leant on by a larger country the other side of the pond certainly has had an influence on launch policy in the UK.
Likewise, I'd ride any vehicle designed by Colin Rowe, he's a really good engineer. Damian's the front man, so if it were all him, you'd be likely to have an onboard bar and be missing something like the parachute;-)
Not the same guys at all. In fact I was fortunate enough to help out on the launch of the Top Gear Reliant Robin, and the people behind the Robin are in a different league. They are really clued up and know what they are doing when it comes to launching stunt rockets.
Ironically, they were building the Top Gear Reliant Robin Shuttle no more than a couple of miles from Bennett, and he had no idea:-)
> Yes, a friend of mine went to a talk by you guys and saw your air cooler thingy. Very impressive.
> And that's as far as it will get. That's my point.
In all fairness, it's not clear to people looking at the technology based on the website how far things have progressed, but bare in mind that the Reaction Engines website isn't updated with all the current developments. Things have progressed practically since then.
> How does it increase the profit margin of insurers? How will City workers get a bonus out of it? How will it reduce Tesco's logistics costs?
To be honest, I couldn't tell you. My involvement is mainly on the propulsion side.
> Some science and engineering papers will get written and in 50 years time someone will have a similar idea and crib from your plans.
I understand your cynicism, but I would hope something more concrete can come of this.
> Britain is a festering pit of racism, conceitedness and cynicism. Bread and the Circus. Celebrity culture, you get the idea.
Yup, and I know where you are coming from.
> Bristol Spaceplanes had better relocate if it wants to see its ideas flourish.
I can't speak for Bristol Spaceplanes, since they are a separate company, located a couple of counties away from Reaction Engines, but knowing people in both companies, I don't think they are planning on moving:-)
> From what I read on their website, "has designed" really ought to be "has been offered some
> money to think about how such a thing might be designed" - they're not designing yet
You may want to revisit that statement. Take another look at the website at the photos and video of one of the engine test rigs. If not having been designed includes test runs of test articles, then yes, it hasn't been designed, but that would be a slightly different definition of not having been designed to the one I am aware of;-)
I know the part I am involved with on the engines exist, because I am sat here this evening working on it!
> Mark my words, this will sit firmly on the drawing board
Well, apart from the bits that have been built that is. Go take a look at one of the engine test rigs on the Reaction Engines website, or even take a look at the youtube video of one of the test runs of that test rig.
Note: I must declare an interest here. I'm lucky enough to be involved on the engine side of things.
First of all, what are you thinking even buying from PC World in the first place? Everyone knows they are overpriced, have dreadful after sales service, and have clueless sales droids who generally can't spell Linux, let alone know how to use it. About the only thing that isn't overpriced there is printer paper. I wish you well, but I'd be very surprised if you get far with them. They seem to think the world consists of Windows, with a token ghetto into which they unfairly throw anything by Apple.
Once in a blue moon, you may come across a sales assistant there who actually has a passing interest in computers, but the majority are (a) under 20 and seem to be on some government sponsored young people's job's for morons scheme, and (b) more interested in texting their friends on their mobile phones than serving customers.
And you then expect them to be able to deal with a customer with a clue? They'll revert to the only thing they are comfortable with "it's not windows, therefore it must be bad and must void the guarantee". We know that they are blatantly in the wrong here, but I suspect it will be expensive to retain a lawyer to give them the legal kicking they so richly deserve.
I don't think I know anybody who hasn't got a horror story about PC World. They are useless.
> No, the resentment comes because he's largely the Keystone Kops of the > alt.Space community - constantly blundering about and making bonehead > mistakes because he charges ahead without a great of thought and often > making mistakes that common good practice would have prevented.
Really? Compared with a lot of the competition, especially for the X-prize Cup, he is by far the most credible contender, and somewhat more rigorous it would seem. Yes, things have gone wrong, but he is openly presenting the failures. You know full well large companies lack this openness and make similar errors, they just are not open about it.
Compared with some of the former X-prize contenders who are still crawling around and were only ever PR exercises for ego aggrandisement, again, Armadillo comes out remarkably well, and way ahead of those who've just presented paper studies or launched clusters of HPR motors and claimed they're building manned rockets.
> And the hell of it is - a competent engineer (with Carmack's money > and like Carmack unfettered by bureaucracy) probably could do better > on the same amount of money.
So where are they then? Not all competent engineers are penniless, so if they really were into space in the same way as John Carmack is, then why haven't they put their money where their mouth is to prove their approach is better. I'm sure you'll argue that it is because to do it properly it costs a lot more money, but that isn't always true. The majority of aerospace engineers I know are very good at talking the talk, but when it comes to actually doing anything practical, they can't even do the bolts up on a rocket motor nozzle plate properly.
Also, they seem to have chips on their shoulders the size of Olympus Mons when it comes to anyone who isn't from the old boy big aerospace network doing anything that makes them look foolish.
> He suffered a lot of failures early on because he didn't use > aerospace grade wiring harnesses
And?
He learnt.
I remember working on a spacecraft payload a while back where some aerospace engineers went nuts that we weren't using aerospace qual components. Strangely enough, the payload worked.
I'm overseeing a propulsion related project right now, where a lightweight, yet effective Skunkworks approach has proved to work. I'm sure it wouldn't meet with the approval of such an esteemed expert as yourself, but the company is happy.
Your dislike of John Carmack is evident in all your posts, but there are plenty of us out there working in the space industry who are very supportive of what John and his team are doing.
> Can you elaborate on the problems with restart?
> Are they inherent in the rocket design?
> Is it something that can be resolved over time,
> into a solution that does not involve the
> "many parts" problem?
The advantage of Nitrous Oxide is it's safety because it requires a fair bit of energy to light. The disadvantage of Nitrous Oxide is that for re-ignition, it requires a fair bit of energy to light:-)
See the problem ?
With H2O2, or Liquid Oxygen, you can squirt in a catalyst to relight it. With Nitrous Oxide hybrid rockets, you usually either use a 1-shot pyro grain (as used in SpaceShip-1) and many amateur hybrid rockets, or, another trick with amateur hybrids, is to flood the combustion chamber with Gaseous Oxygen and use either high current or high voltage ignition - again, generally 1-shot devices.
So lighting them is straightforward enough. Shutting them down if you have a flow valve, is easy enough, but relighting them when your igniter is now on the ground, several miles below, is somewhat problematic:-) It is inherently a design issue.
It is possible, that a solution could be rigged together using an onboard spark plug based system, possibly with a small GOX tank for reflooding the chamber following a shutdown, however the extra weight could well kill the mass fraction - which is already more of an issue for hybrids than for solids and liquids anyway. In summary, it's not easy, and it's not clear if it is beneficial on a small scale system, although it may well be more solvable with larger commercial hybrid motors.
> While space has tested engines based on H2O2, it was not used.
> H2O2 is very difficult to work with as it must be extremely pure.
> In fact, a little bit of impurity can cause an explosion.
H2O2 has had a bit of a bum rap. It's not actually any worse to work with than a cryogenic oxidiser such as Liquid Oxygen. In fact I have a large drum of H2O2 in the shed for a little pet liquid bi-prop motor project:-)
It is reactive, no doubt about it, and the experience of the Germans in using it in the ME-163 Komet rocket plane in WW2, showed how dangerous it could be if precautions were not taken, or if residual H2O2 sloshed around on landing the rocket plane. However, it worked perfectly well as the oxidiser (with kerosene as the fuel), in Britain's only orbital launcher, the Black Arrow, as well as another British Rocket that predated the Black Arrow, namely the Black Knight suborbital rocket.
No doubt impurities can cause dangerous reactions with H2O2, and the stronger the concentration the better obviously, but you clean the feed lines for it in a similar manner to Liquid Oxygen, and given the widespread use of Liquid Oxygen, then it need not be different for H2O2. However, the FUD that has grown up around H2O2 has meant that it is given a wider berth than it really needs.
> The nice thing about the HTPB/N2O combo is the cost and
> the switchablity. It is basically a solid fuel approach
> but allows multiple start-ups.
HTPB/N2O doesn't actually easily allow multiple start ups. Believe me, I've tried. It can be done with electronic ignition, but is very difficult to achieve reliably. There are means to do it, but the complexity certainly outweighs the benefits in small hybrid rocket motors.
It is however easy to shut down. You literally just close the oxidiser flow valve, and the motor stops.
> For specifics, I was impressed with the H2O2 and
> "shredded tires" fuel of Spaceship One
Just as a factoid, SpaceShip One doesn't use H2O2 (which is Hydrogen Peroxide) as oxidiser, it uses Nitrous Oxide, also known as "laughing gas".
Nitrous Oxide is self pressurising, which is where it scores over other oxidisers (although you take a performance hit because the specific impulse when using Nitrous Oxide is lower than with say Liquid Oxygen). With Hydrogen Peroxide as the oxidiser, you'd need to use a pressurisation tank, most likely of Nitrogen. You still need a pressurisation tank on very large Nitrous oxide powered hybrids, because the pressure drop during the motor burn becomes significant for a large motor, but for smaller hybrid motors, it's less of an issue.
Also, the shredded tires is a media over simplification. The actual fuel is a rubber-like compound, most likely HTPB (which is Hydroxyl Terminated Poly Buta-diene), hence the fact the media probably just call it rubber, because it is such a mouthful!
I've got some more information on hybrid rocket motors and how they work, which I'm slowly building up at:
If you're interested in hybrid rocket motors (and they are incredibly simple, as well as chaper and safer than solid rocket motors and liquid rocket engines), then hopefully it may be informative:-)
> Why would you expect him to be necessrily better at aerospace?
> Because he knows how to optimize 3D rotation matrices to make
> a 3D first-person game?
No. Because he doesn't bring his head-up-butt style of groupthink that "many" (not all) aerospace engineers seem to adopt. The "not invented here" or "we don't think it will work, so it won't work" thinking that has left the space industry behind where it should be for the last few decades.
What John Carmack brings is an willingness to learn and try different ways of doing things. Yes, hardware gets bent when it crashes, but at least he is doing something, rather than sitting in a comfy chair in an office and saying something won't work, and it can only be done one way. The Big Aerospace way.
Slashdot Mirror
Are you actually a rocket geek - or did you just roll that name randomly? Because an actual rocket geek would know how long Alan Bond has been pushing this concept.
I am well aware of how long the concept has been pushed - it makes me realise how long I've been in this game. I know Alan Bond well (in fact I work for him), and I know his co-designer on the previous concept HOTOL well too (Dr Bob Parkinson). I also know, that when they have to battle against entrenched, sclerotic viewpoints of people such as your good self, it can take a long time for development to come to fruition.
What about the tested stuff? That's like having a tested transistor, a tested capacitor, a working prototype of a voltmeter, a well polished stone knife, a properly prepared bearskin - and announcing that you are ready to use them to build a supercomputer. They're virtually meaningless.
And by that, you demonstrate how little you understand of the subject in question, sorry. Your argument is itself meaningless. The various technologies are developed to considerably more than merely component level, and I would hope you are not stupid enough to think otherwise, but are trying to illicit a response. The key is take the various technologies to higher Technology Readiness Levels. Go look up what that means if you are not sure.
Anyone who works around engineering, or who has a working knowledge of engineering, knows the real test is an integrated system. Something Reaction Engines doesn't even have the data to rough out a design before, yet alone build.
Again, that just belies your ignorance of both the process, and in this particular case, the hardware developed. You may benefit from reading the details on their website, as opposed to simply using it as an opportunity to indulge in your love of bashing - that way, you might (a) learn something, and (b) understand why the project is broken down into the distinct areas it is. Yes, I admit I am a physicist who works in engineering, as opposed to an engineer who works in engineering, if that is something you wish to use against me too.
My comments? They aren't negative - they're factual. They only seem negative and in need of fact checking because most self proclaimed rocket fanboys are like you, completely and utterly ignorant.
Actually, your comments are most certainly not factual, because if you had read the information first, and had understood anything of what is written on the project, you would understand how lacking in clues you are.
If by rocket fanboys and ignorance, you mean degrees in physics, many years of experience of working on developing rocket propulsion, genuine contributions to numerous peer reviewed rocket propulsion papers, and well used copies of rocket propulsion books such as Sutton, Huzel and Huang, and Humble and Larson which are battered because I've had cause to use them out at test sites doing real rocket propulsion testing, then I suppose I am guilty.
So come on Mr Lyons, what is your technical background? I'm sure since you are so able to cast aspersions on so many rocket concepts, that you must have an exemplary background yourself.
Do you have evidence of your assertion regarding funding?
As for the "nothing to show for it but ever spiffier computer graphics", what about the currently built heat exchanger module, the tested heat exchanger, the tested rocket engines, the tested modified jet engine being used to test the precooler, the experimental turbine, the wind tunnel to test frost formation with the hydrogen in the heat exchanger, and a host of other hardware that has been built to test various aspects of the system? Hardly just computer graphics are they?
Note, this time, I must declare an interest here. I work for Reaction Engines on the ED nozzled rocket engine test programme, so I do know what hardware exists, and in fact the reason I am late replying to this thread is due to being at static test firings this week.
Mr Lyons, do you ever check your facts before your usual negative comments on various rocketry ventures around the world?
I'm sorry for any offence caused. I am just very enthusiastic about the cause!
I can understand where you are coming from completely. The task is certainly not easy, but we do believe it is achievable, and as has happened until now at Reaction Engines, the key is incremental steps towards the eventual capability.
;-)
Rocket engines do take a while to develop yes, but a deeply cooled air breathing rocket engine is in some regards less of a big deal than designs where they use a jet engine, a ramjet, a scramjet and a rocket to get into orbit. Yes, there are some elements of it that are fairly complex, but other elements of it that are more straightforward too.
Although the website lists the main projects, there are a lot of intermediate sub projects along the way that have been achieved or are in process at the moment, and as these come together, the more of that capability will be realised. We will do this, because we genuinely believe it is achieveable, we are too stubborn not to, and we owe it to those on HOTOL, Black Arrow and Blue Streak who blazed the trail. Besides which, I'll be out of a job if there isn't something shiny flying in a while
Hmmm, the problem I was thinking of was in pure vacuum. Does the pintle (adjustable central obstruction in the nozzle)
Yes, you'll be pleased to know, I know what the pintle is, I have had to extract it from the motor several times :-) Not straight after testing you'll understand :-)
improve performance in vacuum?
Compared to a bell nozzle, yes, since it is operating at optimum efficiency throughout the thrust regime.
Seems to me that if you wanted almost perfect ISP, you still need a high expansion bell on your nozzle.
Absolutely, you're spot on :-) And in fact, the ED nozzle does have a very large area ratio. Even with the large area ratio, the performance gains compared to a bell nozzle should be greater than any mass hits you take by having a large area ratio nozzle in the ED. In terms of how great, that's what the ED rocket test programme that Reaction Engines is carrying out is designed to find out.
1) The graphics were produced a fair while ago. I daresay they could be improved nowadays. Much of the design work is in Solid Works, so I imagine that could be skinned and modeled accordingly.
2) Reaction Engines is focused on trying to develop an SSTO spaceplane, not a Hollywood movie. If the money was available, yes, I'm sure the graphics could be souped up, but when the budget choice is graphics or components for a rocket engine say, guess what wins in a rocket related company that is focused on developing the hardware?
Personally, I would rather trust a company that bring real hardware that has been tested to the table than a company that just has a bunch of gorgeous CG images and PowerPoint slides.
Actually not. Venturestar was a pure rocket SSTO, as opposed to an air breathing rocket SSTO. Big difference. Because it was reliant solely on pure rocket propulsion, the structural mass required materials that were very light, and one of the reasons it wasn't continued was problems with the composite non cylindrical liquid hydrogen tank, which was a major show stopper.
Skylon gains significantly by being able to use an engine that air breaths to Mach 5.5 before transitioning to pure rocket propulsion.
Thanks for replying... I think some people forget just how complicated (and time-consuming) it is to design a vehicle for space travel when you don't have billions of dollars in your budget.
My pleasure. I'm sat here working on calculations connected with the ED nozzle this afternoon (the rocket side of the engine is the part I am lucky enough to work on), and thought it made sense to reply to some of the comments where I could.
:-)
As you can imagine, there is a lot more going on behind the scenes than is indicated on the website. The problem is, we are rocket people, not PR people, so getting the word out doesn't come naturally, and we spend the vast majority of our time working on the technical aspects
We also have probably an inefficient nozzle design with a tradeoff between greater bell size (and efficiency in vacuum) and lower air drag.
That's why we are developing the ED nozzle :-)
The ED nozzle is a very efficient nozzle design and provides altitude compensation across the thrust operation range. Part of the engine development at the moment is concerned with development of the ED nozzle for this purpose.
Your understanding is spot on.
Then you may need to work on your reading :-)
The precooler tests were run separate to the thrust tests. The thrust tests were related to the ED nozzle work.
As for the reliability, well when I wrote the test plan for the ED nozzle test engine, I can assure you, that reliability was very much part of the plan.
As for you not seeing any prototype being tested, note the photograph of a rocket shaped object with hot flame coming out of it in the News section?
I'm sorry the photograph isn't any better, but none of us were prepared to step outside the bunker during the hot firings. I'm working on improving the photos taken during test runs.
> it is to design a workable scramjet system.
No they didn't. You may wish to research HOTOL a bit more. It didn't use a scramjet. Not only do I know the designer of the engine of HOTOL, I am working with him on a UK rocket engine as part of the successor to HOTOL, namely SKYLON.
Scramjets are unlikely to be the answer. The US seems fixated on them, but that doesn't mean they are the most effective solution.
Also the comment regarding the maintaining of the monopoly for US launch companies at that time isn't a million miles away either. Read up on the politics, talk to politicians of that time, and you'll find the political dimension based on being leant on by a larger country the other side of the pond certainly has had an influence on launch policy in the UK.
Likewise, I'd ride any vehicle designed by Colin Rowe, he's a really good engineer. Damian's the front man, so if it were all him, you'd be likely to have an onboard bar and be missing something like the parachute ;-)
Not the same guys at all. In fact I was fortunate enough to help out on the launch of the Top Gear Reliant Robin, and the people behind the Robin are in a different league. They are really clued up and know what they are doing when it comes to launching stunt rockets. Ironically, they were building the Top Gear Reliant Robin Shuttle no more than a couple of miles from Bennett, and he had no idea :-)
> Yes, a friend of mine went to a talk by you guys and saw your air cooler thingy. Very impressive.
:-)
> And that's as far as it will get. That's my point.
In all fairness, it's not clear to people looking at the technology based on the website how far things have progressed, but bare in mind that the Reaction Engines website isn't updated with all the current developments. Things have progressed practically since then.
> How does it increase the profit margin of insurers? How will City workers get a bonus out of it? How will it reduce Tesco's logistics costs?
To be honest, I couldn't tell you. My involvement is mainly on the propulsion side.
> Some science and engineering papers will get written and in 50 years time someone will have a similar idea and crib from your plans.
I understand your cynicism, but I would hope something more concrete can come of this.
> Britain is a festering pit of racism, conceitedness and cynicism. Bread and the Circus. Celebrity culture, you get the idea.
Yup, and I know where you are coming from.
> Bristol Spaceplanes had better relocate if it wants to see its ideas flourish.
I can't speak for Bristol Spaceplanes, since they are a separate company, located a couple of counties away from Reaction Engines, but knowing people in both companies, I don't think they are planning on moving
> From what I read on their website, "has designed" really ought to be "has been offered some
;-)
> money to think about how such a thing might be designed" - they're not designing yet
You may want to revisit that statement. Take another look at the website at the photos and video of one of the engine test rigs. If not having been designed includes test runs of test articles, then yes, it hasn't been designed, but that would be a slightly different definition of not having been designed to the one I am aware of
I know the part I am involved with on the engines exist, because I am sat here this evening working on it!
> Mark my words, this will sit firmly on the drawing board
Well, apart from the bits that have been built that is. Go take a look at one of the engine test rigs on the Reaction Engines website, or even take a look at the youtube video of one of the test runs of that test rig.
Note: I must declare an interest here. I'm lucky enough to be involved on the engine side of things.
First of all, what are you thinking even buying from PC World in the first place? Everyone knows they are overpriced, have dreadful after sales service, and have clueless sales droids who generally can't spell Linux, let alone know how to use it. About the only thing that isn't overpriced there is printer paper. I wish you well, but I'd be very surprised if you get far with them. They seem to think the world consists of Windows, with a token ghetto into which they unfairly throw anything by Apple.
Once in a blue moon, you may come across a sales assistant there who actually has a passing interest in computers, but the majority are (a) under 20 and seem to be on some government sponsored young people's job's for morons scheme, and (b) more interested in texting their friends on their mobile phones than serving customers.
And you then expect them to be able to deal with a customer with a clue? They'll revert to the only thing they are comfortable with "it's not windows, therefore it must be bad and must void the guarantee". We know that they are blatantly in the wrong here, but I suspect it will be expensive to retain a lawyer to give them the legal kicking they so richly deserve.
I don't think I know anybody who hasn't got a horror story about PC World. They are useless.
> No, the resentment comes because he's largely the Keystone Kops of the
> alt.Space community - constantly blundering about and making bonehead
> mistakes because he charges ahead without a great of thought and often
> making mistakes that common good practice would have prevented.
Really? Compared with a lot of the competition, especially for the X-prize Cup, he is by far the most credible contender, and somewhat more rigorous it would seem. Yes, things have gone wrong, but he is openly presenting the failures. You know full well large companies lack this openness and make similar errors, they just are not open about it.
Compared with some of the former X-prize contenders who are still crawling around and were only ever PR exercises for ego aggrandisement, again, Armadillo comes out remarkably well, and way ahead of those who've just presented paper studies or launched clusters of HPR motors and claimed they're building manned rockets.
> And the hell of it is - a competent engineer (with Carmack's money
> and like Carmack unfettered by bureaucracy) probably could do better
> on the same amount of money.
So where are they then? Not all competent engineers are penniless, so if they really were into space in the same way as John Carmack is, then why haven't they put their money where their mouth is to prove their approach is better. I'm sure you'll argue that it is because to do it properly it costs a lot more money, but that isn't always true. The majority of aerospace engineers I know are very good at talking the talk, but when it comes to actually doing anything practical, they can't even do the bolts up on a rocket motor nozzle plate properly.
Also, they seem to have chips on their shoulders the size of Olympus Mons when it comes to anyone who isn't from the old boy big aerospace network doing anything that makes them look foolish.
> He suffered a lot of failures early on because he didn't use
> aerospace grade wiring harnesses
And?
He learnt.
I remember working on a spacecraft payload a while back where some aerospace engineers went nuts that we weren't using aerospace qual components. Strangely enough, the payload worked.
I'm overseeing a propulsion related project right now, where a lightweight, yet effective Skunkworks approach has proved to work. I'm sure it wouldn't meet with the approval of such an esteemed expert as yourself, but the company is happy.
Your dislike of John Carmack is evident in all your posts, but there are plenty of us out there working in the space industry who are very supportive of what John and his team are doing.
> Are they inherent in the rocket design?
> Is it something that can be resolved over time,
> into a solution that does not involve the
> "many parts" problem?
The advantage of Nitrous Oxide is it's safety because it requires a fair bit of energy to light. The disadvantage of Nitrous Oxide is that for re-ignition, it requires a fair bit of energy to light :-)
See the problem ?
With H2O2, or Liquid Oxygen, you can squirt in a catalyst to relight it. With Nitrous Oxide hybrid rockets, you usually either use a 1-shot pyro grain (as used in SpaceShip-1) and many amateur hybrid rockets, or, another trick with amateur hybrids, is to flood the combustion chamber with Gaseous Oxygen and use either high current or high voltage ignition - again, generally 1-shot devices.
So lighting them is straightforward enough. Shutting them down if you have a flow valve, is easy enough, but relighting them when your igniter is now on the ground, several miles below, is somewhat problematic :-) It is inherently a design issue.
It is possible, that a solution could be rigged together using an onboard spark plug based system, possibly with a small GOX tank for reflooding the chamber following a shutdown, however the extra weight could well kill the mass fraction - which is already more of an issue for hybrids than for solids and liquids anyway. In summary, it's not easy, and it's not clear if it is beneficial on a small scale system, although it may well be more solvable with larger commercial hybrid motors.
> as the oxidizer and not Hydrogen Peroxide -- perhaps
> I was on the former when I posted?
You'd notice the difference I'm sure :-) I know I'd rather be on the former :-)
> But I think my point, and yours, still stand.
Absolutely :-)
> H2O2 is very difficult to work with as it must be extremely pure.
> In fact, a little bit of impurity can cause an explosion.
H2O2 has had a bit of a bum rap. It's not actually any worse to work with than a cryogenic oxidiser such as Liquid Oxygen. In fact I have a large drum of H2O2 in the shed for a little pet liquid bi-prop motor project :-)
It is reactive, no doubt about it, and the experience of the Germans in using it in the ME-163 Komet rocket plane in WW2, showed how dangerous it could be if precautions were not taken, or if residual H2O2 sloshed around on landing the rocket plane. However, it worked perfectly well as the oxidiser (with kerosene as the fuel), in Britain's only orbital launcher, the Black Arrow, as well as another British Rocket that predated the Black Arrow, namely the Black Knight suborbital rocket.
No doubt impurities can cause dangerous reactions with H2O2, and the stronger the concentration the better obviously, but you clean the feed lines for it in a similar manner to Liquid Oxygen, and given the widespread use of Liquid Oxygen, then it need not be different for H2O2. However, the FUD that has grown up around H2O2 has meant that it is given a wider berth than it really needs.
> The nice thing about the HTPB/N2O combo is the cost and
> the switchablity. It is basically a solid fuel approach
> but allows multiple start-ups.
HTPB/N2O doesn't actually easily allow multiple start ups. Believe me, I've tried. It can be done with electronic ignition, but is very difficult to achieve reliably. There are means to do it, but the complexity certainly outweighs the benefits in small hybrid rocket motors.
It is however easy to shut down. You literally just close the oxidiser flow valve, and the motor stops.
> "shredded tires" fuel of Spaceship One
Just as a factoid, SpaceShip One doesn't use H2O2 (which is Hydrogen Peroxide) as oxidiser, it uses Nitrous Oxide, also known as "laughing gas".
Nitrous Oxide is self pressurising, which is where it scores over other oxidisers (although you take a performance hit because the specific impulse when using Nitrous Oxide is lower than with say Liquid Oxygen). With Hydrogen Peroxide as the oxidiser, you'd need to use a pressurisation tank, most likely of Nitrogen. You still need a pressurisation tank on very large Nitrous oxide powered hybrids, because the pressure drop during the motor burn becomes significant for a large motor, but for smaller hybrid motors, it's less of an issue.
Also, the shredded tires is a media over simplification. The actual fuel is a rubber-like compound, most likely HTPB (which is Hydroxyl Terminated Poly Buta-diene), hence the fact the media probably just call it rubber, because it is such a mouthful!
I've got some more information on hybrid rocket motors and how they work, which I'm slowly building up at:
http://www.ukrocketman.com/rocketry/hybridscience. shtml
If you're interested in hybrid rocket motors (and they are incredibly simple, as well as chaper and safer than solid rocket motors and liquid rocket engines), then hopefully it may be informative :-)
> Because he knows how to optimize 3D rotation matrices to make
> a 3D first-person game?
No. Because he doesn't bring his head-up-butt style of groupthink that "many" (not all) aerospace engineers seem to adopt. The "not invented here" or "we don't think it will work, so it won't work" thinking that has left the space industry behind where it should be for the last few decades.
What John Carmack brings is an willingness to learn and try different ways of doing things. Yes, hardware gets bent when it crashes, but at least he is doing something, rather than sitting in a comfy chair in an office and saying something won't work, and it can only be done one way. The Big Aerospace way.
Close. Newton Seconds is actually a measure of "Total" Impulse.