Sounds an excellent plan, though I bet Rui's dreading the frock already.
The El Reg Special Projects Bureau (SPB) is pleased to announce we've finally come up with what we reckon is a worthy successor to our Paper Aircraft Released Into Space (PARIS) project. After a good deal of mulling as to how we could use our PARIS experience to launch an even more improbable and audacious plan to keep the UK …
The project might be LOHAN but as any fule kno, the ship itself will need a nickname.
Following on from the success of PARIS may I humbly propose 'High Hilton', complete with a suitable graphic? Perhaps her ladyship in reclining form underpinned with a long white line representing...err...the exhaust gasses.
It has a nasty tendency to diffuse through most things, so that might make the other materials more costly. I also wonder if the legal situation with launching a highly flammable hydrogen balloon differs with that of launching an inert helium one? Anyone know more on this?
In the open air you can't get an explosive hydrogen/air accumulation. Hydrogen on its own has no explosive properties. If someone gets really careless and manages to ignite the balloon, it'll burn strongly upwards (away from them).
It's not well-known that the majority of the passengers in the Hindenburg disaster survived. Of those who didn't, many died of wounds caused by jumping from too great a height, or by heavy metal components of the airship falling onto them. And that was one helluva large balloon.
The fatal flaw of the Hindenburg, was using an inflammable material for its outer skin. You wouldn't do anything that silly, would you?
So long as you stick within model aircraft limits (3m wingspan, 7.5Kg weight), no license is required for a UAV. For larger airframes, a specialised license can be obtained. I'm going to hazard a guess and say Lester probably knows all this, or knows a suitable "pilot" (quotes due to it being, err, a UAV).
Of course the rules in Spain may be different to the rules in the UK. Go have a look at the BMFA's website for the latest Handbook and other resources.
What I do know is BMFA liability insurance (which is highly limited and only applies on approved land, etc, etc, consult their site for more info) does cover you for up to class M rocket engines, which is pretty fecking huge. We're not talking "firework on a stick". More like "amateur suborbital missile."
I'm gonna guess that Lester has probably done research in this department though, and might even have larger rocket classes planned.
At least, I'm sure we're all hoping he has. Teehee.
>> PARIS was interesting, but it didn't 'fly'..
> Err, what did it do then? Plummet very, very gently?
It _may_ have managed to glide, although with no evidence of it even being gently hand launched into long grass before the big flight, it's hard to see how it could have been anywhere near trimmed for that.
Not that there was any allowance made for trimming it either.
Very pleased that this one looks like it might be more of a plane and less of a 'lightweight plane shaped object dropped from a height'.
+1 to Ardupilot, there are enough other challenges to overcome to get this one to work.
Probably need tweaking to avoid an Ariane 5 style 'outside the design parameters' disaster though.
Well, it looks like you wouldn't call what a folded paper aeroplane does when thrown off the n-th floor balcony 'flying' either.
PARIS managed to end its flight with a surprising lack of damage, from which I dare to draw the conclusion that the craft went relatively slow, which again means a near-horizontal attitude.
OK, it wasn't guided in any way, but in common parlance the craft, seeing that it did no plummeting to speak of and managing airborne time and distance travelled consistent with the aforementioned lack of plummeting, was flying.
I'm reasonably up on old Superman comics (finally gave up after the Brainiac-13 fiasco) but I don't recall a NOM-EL (unless you really want to spell LEMON backwards).
There is however a Mon-El (you see? You shouldn't test old farts with this sort of thing) who is actually Lar Gand from the planet Daxam. He ends up in the Legion of Super-Heroes, my favourite book.
And now... back to looking for a job...
Beer mats and non-smoking places
Wouldn't it be nice if one could get a paper cap to fit over the beer glass, which has all the advertisements on it, but signifying "This is not finished!!!" when one pops outside for a smoke. Stops the barstaff whipping the half-full glass away.
THEN, we could use the clean beermats for creating useful projects as in the old days, like PARIS, or LOHAN, or a GSM cellular system.
Just a thought....
You'll need it. And a lot of permits to fly it too. Autonomous aircraft need an (expensive) permit I believe, although not sure about Spain, but I expect so. Even small ones. The flight control software needs to be completely foolproof and tested to the nth degree (imagine it going wrong and crashing on someone - you'll need insurance).
Anyway notwithstanding that, flight control software is pretty difficult, as is rocket ignition in flight.
Still, like I said, good luck!
...and you could probably achieve it with fibreglass sheets and resin. Pretty cheap stuff, usually used for making/fixing model helicopter bodies. Could make for an awesome monocoque airframe, leaving plenty of room inside for rocket engines. Will you be just buying off-the-shelf Estes stuff, or making your own engines? Also are you considering solid, liquid or hybrid rocket engines? From what I recall, the Top Gear shuttle attempt used latex and nitrous oxide. Could be worth contacting Rocket Men Ltd to see if they'd like to join forces or find out how much it'd cost to hire their expertise.
As you're going above GPS heights, I'm going to guess you'll need to work without it, at least at the start of the launch. Solid state barometers can be fettled to work as altimeters, and you already know about solid state gyroes and accelerometers. Problem is, gyroes will tend to drift so you will need to find a way of detecting absolute orientation every now and then (as opposed to the gyroes just telling you how much you rotated since the last measurement). You could go for optical horizon detection (probably a good option as you'll be way above cloud level and presumably launching in the day, even if it would be computationally expensive to analyze a couple of webcam feeds). Another more iffy method is magnetic detection. Apparently the difference in the Earth's magnetic field is measurable over a pretty short altitude difference, so sensors in the wingtips could detect whether you're flying level or not (at the expense of not knowing if you're upside down or not).
Another (better) method of horizon detection is putting IR sensors in the wingtips and looking for a warmer earth versus a cooler sky. This is used in auto-land mechanisms that are already available, however they have their own drawbacks. You'd need extra sensors above/below to detect inversion, and the behaviour of an autoland system might get a little odd if it approaches a tree line or hilly terrain. I've seen some reports saying the aircraft will automatically bank away from the tree line, but a sharp bank at low altitude will likely end up with a nosedive into the floor.
Have you thought about possibly taking manual control of the aircraft once it gets low enough, presuming you can find the thing in the sky? Can we have a re-attempt at trying to track the craft via telescope? Also, please put a forward-facing camera on the aircraft this time. PARIS was awesome in very many ways, but it was a shame to not be able to see the ride down from the Playmonaut's perspective.
Also, perhaps it's possible to have the engines as external modules that get jettisoned after exhaustion? Extra brownie points for having them come down via parachute, shuttle-SRB-style. Extra extra brownie points for sticking cameras on them too.
For location, maybe you could use a lightweight, hacked smartphone with GPS in addition to the radio beacons? It's likely the batteries would freeze at very high altitude, but so long as it wakes back up properly once things warm up a little (and presuming it comes down in an area with some signal) you'd have a very precise way of recovering your spaceplane (and perhaps SRBs).
Maybe put a radio beacon on the floor somewhere and see if the plane can home in on it?
My word, this post is getting long. Hopefully not too long. Dammit Lester, there's just so much stuff to think about here. I'm envious you're getting to do it at all though!
If El Reg. can't afford jetex motors*, I'm sure there's a cheap Chinese alternative. However, considering that, wouldn't a few shotgun cartridges give enough thrust? After all, it's not being launched from a "Grassy Knoll" (Downvotes from yanks expected and deserved)
Problem is, whatever signal you're getting from the gyro has to be converted to digital at some point so the onboard computer can deal with it. Digitisation means quantisation, which means quantisation error, which means drift. Unfortunately we don't have infinite-bit ADCs just yet, nor computers that can deal with infinite accuracy. That and a piezo gyro from a model shop is probably vastly cheaper.
Still, there are no silly ideas when compared to the overall goal of flinging a model aircraft into space. Let's keep going and give Lester some inspiration!
As long as you design the aircraft to be positivly stable it should self right on release, basically having the centre of gravity below the centre of lift solves the problem.
After that it's a question of having it head in the right general direction, obvioulsy GPS would be ideal and I believe it's possible to get around the height limit that's mostly an artificial imposition anyway. One of those camera attached to met ballon groups did it a while back. if not just have it follow an appropriate compass direction until it gets below the height limit and then revert to GPS guidance.
With a dynamically stable platform guidance shouldn't be that much of an issue as once you remove the steer command it should steady up on the new heading.
I think you could achieve all the above with a smart phone - GPS, compass, guidance control software and link it to the control system via USB. The main thing you'd need this time is some sort of heater to stop the batteries freezing!
Well it's not so much horizon detection as attitude detection, and horizon detection is possibly the only way of doing it that's within reach of Garden Shed Engineering.
As for why, well the idea according to the article is to fly the thing back to base under autonomous control. As well as you build any airframe, all it takes is a gust of wind to completely fuck your orientation up. Under any realistic conditions, simply relying on dihedral wings and rudder control is not going to work very well at all. While there are free-flight gliders that can circle around, they aren't really guided and may well end up anywhere. They also tend to be flown in conditions that are relatively calm compared to whatever might be blowing about up at 30, 40 or 50,000 feet. So long as you can detect attitude, you can keep the wings at a sensible level and therefore not have to worry about suddenly being flipped upside down - or at least, quickly correct things if you do get flipped. Plus at the speed a rocket engine is likely to take you, anything other than sharply swept or delta wings are likely to get ripped straight off. I really want to see that F19 airframe in fibreglass!
Using a hacked smartphone (or multiple if Lester goes for detachable engines) for everything is a plan though. Cheapy droidphones are under a hundred quid and have more than enough computational grunt for the task. Plus GPS, plus a 3G chipset, unless there are smaller, lighter System On Board platforms that have 3G to talk to home with.
Mind you, what would it take for a long-ish range nav beacon to send gpsd-compatible messages over rtty? Much better than trying to triangulate a simple ping, and no need to rely on mobile phone coverage.
"As you're going above GPS heights, I'm going to guess you'll need to work without it, at least at the start of the launch."
Rubbish. GPS works in the ISS orbit. COTS systems have imposed limits of 60,000 ft and 999 kts, to stop evil people from using an off the shelf system to guide a home-brew ICBM, but that's not a technologoical limit and apparently Garmin kit doesn't have the altitude limit implemented.
At least one person has used a GPS-based auto-pilot to return a met. balloon-launched glider back to base. This reached 74,000 ft and, once the auto-pilot sorted out the trim, was able to head on back home - until it rammed the top of a mountain that happened to be in the way .
Lester, if you don't know this site, its well worth a look. Its well written and has a lot of information about the temperatures and speeds met in flight as well as good analyses of what went wrong, why, and how the problems were fixed.
Still, if the module aboard Vulture 1 performed okay, maybe it can be re-used. The thing I'm scared about is that some forums are saying the height+speed limits are imposed on a lot of modules as an "OR" operation, so height exceeded OR speed exceeded. Some are imposed as an AND operation, so height AND speed exceeded. If the Vulture 1's GPS module is an AND, then it'll be fine for measuring a slowly floating balloon's height all the way up to space. However if this rocket plane goes above 999kts, then you could end up with GPS cutting out just when it's needed most: to measure peak height. 1150mph might sound like a big ask, but not out of the range of even a modestly powerful rocket engine in the upper atmosphere with nothing substantially heavy attached to it.
Though as this is El Reg, and not some bunch of random schmucks, maybe they could be trusted with mil-spec kit?
Should be possible using one of the sensors in a smartphone as long as it's securely fixed to the airframe. I don't think speed is necessarily an issue either, it only has to go up fast, coming back down could be done at a more leisurely pace, or using one of the more stable lifting body concepts from the X-Series of aircraft to reduce the control issues.
Going up could be tricky but if you can work out the optimum angle of attack it shouldn't be that hard, although some sort of air density sensor would be useful*. This assumes you want the lift from the wings for going up rather than relying on pure thrust.
*You could just use a temperature sensor and work the rest out mathematically, you just need an estimation of the Indicated Air Speed that's accurate enough for your control inputs not to cause you to depart controlled flight.
These tend to be accelerometers, which would be as useless as trying to fly a plane at night in clouds by looking out of the window. Unfortunately the acceleration caused by getting kicked up the backside by a rocket engine will severely skew a smartphone's idea of where "down" is. This is where using a solid state gyro (three of them, they cost about £30-£50 each from an RC supplies shop) would come in handy, alongside horizon detection. The ready-for-RC gyro blocks are quite lightweight, or you can buy the raw components themselves from CPC or Maplin or whoever for even more weight savings. Hell, I have a Blade mCX micro-copter here with a 7 inch rotor span, that has a single-axis tail gyro welded onto the logic board. They are tiny, on the order of Microchip-sized.
See the reason you need additional horizon-detection measures (be they optical, IR or whatever), is that gyroes don't give you an absolute attitude reading and accelerometers are useless for this purpose when you're undergoing acceleration (or even just wobbling about a bit). Gyroes will tell you how much you've rotated by, but they don't know where "down" is. By using horizon detection, you get an absolute measure of where up and down is that can be taken, say every second or so, whereas the gyroes respond much faster and can be used to interpolate by saying "well up and down was THIS way 0.02 seconds ago and the gyroes say I've rotated THAT many degrees, so up and down must be THERE." Accelerometers can be used for their intended purpose of logging the fact that "holy crap, I'm pulling 10g on this rocket burn, woo fucking hoo!"
Now you could use solid state barometers to measure both airspeed AND altitude. Airspeed barometer would be attached to a pitot tube, the altimeter one inside the airframe out of any significant draughts. Of course they'd both need calibrating, but the mathematical formula for turning millibars into feet above sea level is pretty well documented. If nothing else it would be a backup or redundant telemetry system in case the GPS module does decide that Lester is trying to bomb the White House and craps out until it descends by a few thousand feet/slows down a touch. Yeah, apparently if the GPS does crap out there may be a bit of hysterisis - it won't just flick back on the minute you go below 60,000ft/1150mph, and there may be a considerable delay.
This is turning into another long post isn't it?
It's been a while since I had anything to do them beyond using the results.
As you allude you can use gyros and accelerometers to get an absolute attitude reading as long as you integrate the results a couple of times (INS systems do this in aircraft/submarines etc.), i.e. I was here, I've been pulling 10g in this direction for 5 seconds so I must be there now. Similarly with gyros, I've rotated this way at 3 degrees a second for 2 seconds so I must be 6 degrees right wing low etc. Theoretically as long as they know where down is when you start everything's good but you'd have to run some tests to see if the fidelity is good enough.
Now what I don't know is if that's more of an overhead than just using the camera on a smartphone* to recognise the horizon is squint, the one issue I can see is that you'll need at least two cameras, one for pitch and one for bank and if the horizon is out of the field of view some way of coping, possibly more cameras.
Solid state barometers are also a good idea for IAS and Altitude I'm guessing they too cost much less than I thought, of course if you get the OAT as well you can figure out the Mach number...
*I'm going to keep suggesting smartphones as I'm taken with the idea for some reason. Wonder if I can get one to fly my RC helicopter...
A little more info: http://www.fas.org/spp/starwars/offdocs/itar/p121.htm gives the civilian limitations as 60,000 ft AND less than 1000kts
However, I've seen unattributed statements that many civilian units use an OR relationship instead: http://gpsinformation.net/main/gpsspeed.htm and, as I said before, at least some Garmin units are said to limit speed reporting but not altitude.
Military/space-rated GPS works on the ISS (and Shuttle?). It will apparently work at up to 3000km altitude - which makes sense since the GPS constellation orbits at 20,200 km, so the angular change from ground level to 3000km isn't very significant.
I'd have a look at DIY Drones for the basis of the autopilot. Most of the groundwork has been laid with their APM; they have good hardware and a well developed IMU. Don't think anyone has taken one that high or fast before though.. The components they use on the distributed board almost certainly wont be up to the job, but a custom pcb+bom should be quite easy - I'd be up for helping knock one up for sure.
However a single balloon would have to be inflated quite a way to lift all the gear, and would therefore pop at a lower altitude. Multiple balloons would be inflated much less so, and could go higher before going boom.
That and the cluster could be arranged so no balloons are touching. Think balloon-----string----balloon----string---etc. Or triple cluster of balloons----string----another cluster----etc. The triple cluster would mean the string can go up the middle of the three and not rub against taught latex. Any failures mean only a single cluster goes ka-pop.
Of course, you could have sensors that measure internal vs external pressure and vent gas accordingly, but that's a whole new complex kettle of fish on top of the existing rather complex autonomous rocketcraft.
That, and you'd want to arrange it so that the most-inflated (and thus earliest to pop) balloon triplet is on the bottom, so that there's no knot plus balloon remains falling on the lower balloons, possibly causing a chain reaction.
You do want to make sure that the release mechanism is not triggered by the jerks of the successive clusters popping, but only by the total loss of lift after the final balloon gives up.
As for venting, simplest would of course be an overpressure valve rated at, say, 75% of the balloon bursting pressure, but there's always the risk of stuff icing up.
LOHAN is too low brow, beside which most of the team would probably end up in pokey after refusing to attend the Betty Ford clinic.
Personally, I believe it should be an evolutionary name.
PARIS SSC? (Plastic Aircraft Released In Space Surely Some Cockup?)
PARIS TNG (Plastic Aircraft Released In Space The Naughty Generation)
PARIS The Quickening
Ok,,, I'll get my coat!
I rather wish I had thought of this for PARIS. But the possibility remains.
How about including a little science payload? In this case, a stack of photographic film to detect cosmic ray shower particles? Within the allowable payload, this might mean only limited amount is possible, but the possibilities of reproducing some old school science is very cool. With a modern twist it should be possible to build a stack of film to form a cube. Once retrieved and developed it could simply be scanned on a reasonable film scanner, and then massaged into a 3D volume. The longer and higher it gets on the flight the better. Sorting out the design, testing and validating of the experiment might take some effort, but it would be really nice to see.
For a very British tie in, you can't do much better than this:
Will you be reusing the PARIS release mechanism?
How about a release on balloon burst method? The craft sits near-vertically nose upward on the side of the also-vertically-mounted payload box, supported by a pair of simple hooks around the trailing edge of the wings where they join the fuselage. Angled outwards slightly to ensure the craft clears the payload and balloon debris. The balloon is attached to a small box containing a spring plunger with the spring fully compressed by the payload's weight, with the payload box support lines suspended from the plunger. When the balloon bursts the spring opens, pushes the plunger upwards to complete an electrical circuit then trigger the rocket motor, filming, etc.
Build in a couple of seconds delay to ensure any balloon still tethered to the payload box has time to roman candle in whatever atmosphere is available and off she goes.
You'll need some method of preventing the plunger from completing the circuit during the bumping about at launch, though.
Thank you for the wonderful writing and the adventurous sense of experimentation. I chuckled at the name LOHAN, and in keeping with the tradition of PARIS, I can see the link. However, since El Reg is an English production, and like PARIS, I would assume that most of the same team members would be involved as before are English, I would like to suggest the name HELENA (High Earth Launch ExperimeNtal Assembly) after the quirky but quintesentially English Cinema Rose Helena Bonham Carter. As I'm sure you're aware, this more seasoned and mature actress and partner of Tim Burton, has played a variety of roles on screen that have captivated viewers wordlwide, as your next space venture will, and has provided enough tabloid fodder for her off screen escapades as well. God's speed, and looking forward to the project moving forward!
So in a sense.. Britain already did it? I mean.. they're a colony so.. *shrug*
Right, let's clear up some details. While that article is rather interesting it's an unpowered glider, now I imagine LOHAN will be gliding back but I presume a rocket booster will be used to achieve greater altitude?
Now the airframe.. I guess carbon fibre is a might-as-well?
Gosh this is so frickin awesome.
But the descent is going to be the hard part. Assuming it survives the ascent.
Time, I think, for a really bold approach. A mini-Orion rocket craft.
It is just possible that hundreds of tiny thermonuclear devices may be beyond even your fine group of shedgineers but an array of conventional shaped charges pointing aft, attached to a massive pusher plate should do just as well. Symmetrically fired pairs, triples or quads would provide linear motion, with carefully calculated offsets from the center of the pusher to provide steering.
In a LOHAN context the resultant intermittent savage thrusts should not be a significant issue.
If you need a control platform for your UAV one you might wish to look at is Paparazzi:
One thing to check with the GPS unit is to check how they are limited, I believe some have an altitude limit and some have a velocity limit, and possibly an acceleration limit or a combination of all , im guessing your not going to actually get up to 515m/s which is i think the velocity limit, so you'd want to make sure your gps reciever will let you exceed the 60,000ft limit if you going less than 515m/s
The US government has put on restrictions on GPS that has forced the manufacturers to implement artificial limits to the spped and height where the GPS will work. You will need to get one that has those artificial limitations removed.
IIRC the artificial limits were 18km height, 1k km/h.
"All GPS receivers capable of functioning above 18 kilometres (11 mi) altitude and 515 metres per second (1,001 kn) are classified as munitions" so are hard to get hold of.
So, *technically*, I think this requirement is ($altitude > 18000 && $velocity > 515), but I suspect most GPS receivers will stop above 18km altitude, no matter how fast/slow it's going, just to be sure.
Hoisted on a weather balloon.
I think this may need several though. I'd go for nine or twelve arranged in bunches of three, for a little redundancy. Put enough helium in that you can lose two clusters and still have lift. The more expansion room you have, the higher those balloons go before the rocket has to kick in.
Are there any relevant records that could be challenged here?
If, instead of building this thing in a relatively cramped hobbyist shed (http://www.tigersheds.com/product_detail.asp?prod=9) and bringing it down for a safe landing in the Costa Random, you do away with the wings and make it a steerable spike, for want of a better description, then you would have a potentially viable kinetic energy weapon capable of downing jolly expensive Merkin systems that rely on altitude (Predator, Reaper, assorted long endurance autonomous blimps, etc.) for protection. Perhaps you could find use for the "Predator" (no relation) learning vision system (http://info.ee.surrey.ac.uk/Personal/Z.Kalal/tld.html) that the University of Surrey recently came up with?
Sell this design to various swarthy gentlemen whose daughters weddings have accidentally been turned into charnel houses, swap the resulting opium to buy a really, really, big shed (http://4.bp.blogspot.com/_IptuFGAxXuM/THGvHjx-HZI/AAAAAAAABB0/ayq1WmTMjUE/s400/big-shed.jpg), and go into competition with Mr. Branson.
You might have to stay out of light aircraft and canoes thereafter (http://3.bp.blogspot.com/_lWET_BXRU9c/RlL9KRQ1w_I/AAAAAAAAAiQ/saXIZ95wx3I/s400/burned+canoes.jpg) but, hey, every silver lining has a cloud.
Just a thought.
Solid fuel is definitely the easiest option -- It is just a tube with fuel and a nozzle in one end. Don't use sugar+nitrate -- the caramel will foul your nozzle. A simple mixture is zinc+sulphur. You can (gently) heat it while in the tube to melt the sulphur to make the mixture solid. Since you have a plane, you should go for a slow burn rather than the fast burn appropriate for "pure" rockets.
You could consider putting the rocket in front of the plane, so it pulls the plane rather than pushes it. It will make it easier to avoid spinning while the rocket is burning. A possibility would be a canard-style aircraft with a small control wing in front over the rocket and a wider wing aft (and slightly higher).
At the balloon's bursting point, LOHAN should fire up and seek to gain altitude. GPS guidance,
for trajectory determination and telemetirc tracking. she cooould take high altitude pictures or summut of the sun, our life, there's all sorts of shit you can put in a small machine these days.
p.s. & n.b. gaia is the locally orbiting bit
Silly acronyms aside (important as they may be), it sounds like ultimately what you are going to end up with is some sort of mini auto piloted return vehicle.
Or tiny Air launched cruise missile / glide bomb really, eh? ;)
Unless you're really really really going out to town, I suspect you're not going to be able to carry enough fuel for any significant length of horizontal flight so I suspect you're probably going to end up with a glider with control surfaces. Maybe even some back up propulsion as necessary for course correction.
I am wondering if you'll consider an automated return vehicle much like an RC Foamie. Would something that light suffer terribly by being completely at the mercy of the air currents up there? I can't recall how heavy PARIS was... Would electric props be suffiicient? Nitro will probably give you more performance but I am not sure about the weight compromise.
Mmm... the more I think about it the more I think your return vehicle will probably get the most range out of being predominantly a glider but that means more complicated guidance, riding the currents, sort of like flying a real glider.
But now back to the issue of of the rocket stage...
Are you guys going to use it like more vertically like a ballistic missile, or launch the projectile at a more horizontal trajectory off the balloon (like an air launched cruise missile)?
Between the helium balloon and the rocket stage(stages), how much height / range do you think you will get from each component respectively?
I am wondering if the rocket bit is going to add much, if at all, to the overall range of this vehicle, if it's predominantly going to glide down and if it (and hence the rocket as well) is going to be somewhat limited in size.
First off, I demand recognition for my original LOHAN recursive acronym (http://forums.theregister.co.uk/post/1111223) even if its altitude objectives were contrary to a rockoon.
Next off, as someone with experience building rocket-powered planes (Hasegawa F-104 plastic models with black powder engines) I can give you some tips:
• The propellant you will want to use is APCP, ammonium chloride composite propellant — the stuff inside the Shuttle SRBs, for example. Its specific impulse is much higher than black powder.
• To handle the problem of a stable low-speed launch, you need a rocket that will fly stably in what’s normally an unstable configuration, one with the CG far back. To accomplish this, you need to move the engines to the NOSE of the rocket, like the abort rockets on a human-carrying capsule.
• To obtain thrust from the nose without incinerating the craft, place 3 or more engines in a conical configuration on a mast attached to the glider’s nose, with the engines firing at roughly 30° from the centreline. When the engines burn out, the mast separates (you can use explosives!) and the glider is left with an appropriate mass distribution for a controlled descent.
The RC foamie suggestion is excellent; to obtain one strong and tough enough to withstand almost anything, you can skin the foam with 1/64" (0.4mm) aircraft-grade birch plywood, which is truly an astounding material. I have a sailplane wing I built out of it which is a pure monocoque structure: no foam inside, not even ribs, just some basswood stiffeners on the flat side and air.
One person you certainly want to speak with is Tim Van Milligan of Apogee Components (http://apogeerockets.com/). He is incredibly knowledgeable about rockets and I bet he’d love the chance to work with you guys.
Go all the way to low orbit and win the N-prize (in spirit, if not within the price parameters). Use a two-stage set-up if you have to. Maybe follow the Mythbusters and combine a sausage and NOx first stage with a solid-fuel second stage. That ought to grab some attention
Mine's the one with the kielbasa and mortadella sticking out of the pocket.
I did a quick look around and spotted the Wowings Skua 1500 (http://tinyurl.com/wowings-skua-1500) slope-glider. It has certain attractive properties; it’s designed to be fast; it has the stabilizers at mid-chord; it looks really cool.
It would be nice if the wings could fold or swing back for the high-speed fight and then pop out just before the mast blows off, after the engines have burned out and some coasting time has elapsed. This would further reduce the frontal area; the wings could be locked back and then snap into place with a bungee cord or similar once the engines have burned out and the dynamic loading is low enough. Here’s another opportunity for explosive-bolt technology. :-)
The more I consider the engine-mast idea the better it sounds. It could even be a mounting point for small, cheap video cameras feeding back to Flash storage on the plane (you can reasonably expect to lose the cameras along with the engine pod). The wires might have to pass right past, even wind around, the explosive charges to ensure they don’t foul the separation. BUT DAMN WHAT A VIDEO THAT WOULD MAKE!
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Not wanting to be a killjoy, but I'm fairly sure that "controlled by an autopilot which operates on GPS to fly the machine back to base" is illegal without a license. You can't operate a UAV above 400 feet and without being able to take manual control.
Remember this? http://news.bbc.co.uk/1/hi/england/merseyside/8517726.stm
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First, I vote for Low Orbit Helium Aided Navigator.
Second, your LOHAN concept illustration, for illustration purposes only, no doubt, nevertheless bears an uncanny resemblance to the stealth fighter plastic model that was being sold (here in the U.S. at least) after the plane's existence was known but before anyone in the public had seen one (must have been in the mid-80s). A co-incidence? I bet not.
Slightly different engine choice but it may be interesting to look at the construction / electronics that were use in the home brew cruise missile put together here http://www.interestingprojects.com/cruisemissile/airframe03.shtml
use of jigs to create foam blanks for coating with GRP look like the way to go for a cheap construction method.
What about using a multi stage rocket stack to give more then 2 or 3 seconds of burn time?
The question of flight control for the landing will be interesting especially as the aerodynamics of the craft will need to be understood to have any hope of "flying" the craft back to a known location. Again the Kiwi experience of flight control electronics could be interesting specifically the expertise needed to actually develop the aeronautic software.
The other option is to not attempt a guided airframe but use passive methods such as helicoptering using stowed blades. It may be that the basic guidance controls for a helicoptering device are simpler and the idea of helicopters from space will send the tinfoil hat brigade to their bunkers!
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(Oh, only Americans make successful things in garages. Hewlett Packard, and Apple spring to mind) The Brits build things in different places.
1) The brick 'thunderbox' at the end of the garden...If you no longer have one, as it was destroyed in WW2, then I guess
2) the allotment shed is the only place.
There's a Russian supply ship going up soon. Don't s'pose El Reg has enough influence to persuade them to lob it out of the window? Or has Surrey Uni. got anything happening soonish? They're always cadging rides on something, then tossing out something tiny into orbit.
Personally, I'd have a chat with Branson
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