back to article Can you handle LOHAN's substantial globes?

The matter of our LOHAN's substantial globes has kicked off a right old debate among you, our beloved readers, as rival viewpoints on just how to launch the Vulture 2 aircraft from beneath helium-filled funbags battle for our attention. Click here for a bigger version of the LOHAN graphic To recap, we need to work out just …

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  1. DZ-Jay

    Yay, Friday!

    I'm sorry I don't have anything to add to your plans, for I am not particularly proficient in manual tasks nor in practical maths and physics.

    However, should you consider implementing the whole lot as a computer simulation instead, preferably one running on an 8-bit vintage CPU, then I'm your guy.

    Cheers!

    -dZ.

    http://www.atariage.com

  2. frankgobbo

    Launch platforms

    I don't know how to help with your question, but I do have a thought about the launch platform - watching videos of all those who have sent balloons to "near space", one thing is particularly clear, and that is it's a VERY rough ride up. It really wouldn't take much to rip something with a 2 metre wing span off a launch platform unless it was really firmly connected. And if it's really firmly connected, how exactly do you break that connection to launch?

    Also, with the rapid (verging violent) spinning you see them doing, even in low oxygen/high atmosphere, you really couldn't guarantee a 5 degree launch angle would clear the balloon. It's just as likely it'll be spinning as the launch occurs and the rocket will fly straight into it.

    It's a really, really tricky one.

    REALLY wish good luck for this - can't wait to see it!

    1. Lester Haines (Written by Reg staff) Gold badge

      Re: Launch platforms

      Yup, it is a rough ride, and the wind is a real problem. Agreed about the the launch angle, so we need to find a solution which will guarantee the Vulture 2 clears the balloon.

      1. Marcus Aurelius
        WTF?

        Delayed ignition

        Why not simply drop Vulture 2 off the balloon on command. Your balloon will float up, Vulture 2 will drop a sufficient distance to clear the balloon and then fire its motor, and you can use the control surfaces to get Vulture 2 flying at the right attitude....

        If you drop it off the balloon, you don't need a large distance between balloon and payload, and you don't need a counterweight.

        Now about the choice of helium over hydrogen.....

      2. Jolyon

        Guarantee

        Difficult to come up with any guarantees when it is going to be hard to predict the relative positions and attitudes of the balloon and the rocketplane. Not unimaginable for the balloon to be several degrees offset from the plane in the direction of the launch.

        Launching near (or below) horizontal would obviously work but I guess one of the aims is to attain maximum altitude. It's a bit like the Douglas Adams trick to flying - you want to aim directly at it and miss. It seems early rockoons did just that bar the actual missing and just spurted straight through the flimsy fabric - simple and direct if a bit messy but there's no way your wide load will achieve the required penetration.

        Would be much simpler to just blast your rocket straight through LOHAN's doughnut (or pair of funbags as the case may be) but then you'd need folding wings and that just suggests a bloody mess - if you're not rigid to start with then there's timings and mechanics to consider and your chances of a flop are magnified.

        1. Mike Richards Silver badge

          That sounds really sensible

          The only difficulty with that suggestion is making sure the plane doesn't tumble when it released, but it sounds relatively simple and would avoid too much spin damage on the way up.

      3. Daniel 1

        Then why launch upwards, at all?

        Your last balloon reached 89km. Solid fuel rockets would give, what, in comparison to that? Another couple of hundred meters?

        Launch the thing sideways for maximum cross-range velocity and best glide, when the inner atmosphere is met with.

      4. Daniel 1

        Make that 30km, but still...

        Still begs the question

        1. Stoneshop Silver badge
          Boffin

          That was 89k feet

          So, 27km or 196 brontosauruses. And given that a decent rocket will easily reach 5km when launched from the ground (where air is much denser, so more energy is wasted to drag), it could, in my estimate, add several tens of km's to that.

          1. Daniel 1

            @stoneshop

            Yeah, I did correct the altitude snafu: I typed without thinking.

            However, your assertion about getting 5kms from the ground with a 'decent' rocket... Well, it's true, you can do it, but you're actually talking about something like an Aerotech M1550 Redline, or similar - which is a VERY decent rocket.

            In fact, it's the most powerful type of rocket licensed for civilian use in some countries; and you launch from solid ground (i.e. not a balloon) to get over a mile of altitude, using a proper rocket shell (i.e. something capable of sustaining 8-12Gs of acceleration all the way). Take a look at the videos of Steve Jurvetson (of venture capitalism fame), to see what a real 'mile high' rocket looks like. You cannot launch one of them from any kind of balloon.

            The Register will certainly need to be something like an ACPC-fueled burner, to even ignite, in a near vacuum - and Aerotech are a likely candidate, to provide such a charge - but the actual rocket or rockets are going to be nothing like on the scale of a Redline. It would tear both the plane and the balloon to shreds.

      5. Ian Michael Gumby Silver badge
        Alien

        Clearing the balloon isn't the problem...

        There are a couple of ways to do this...

        1) connect the aircraft to the balloon at the center of its mass. When you drop it, it should go in to a normal, 'flat' glide path. Delay, ignite the engine and then after a second delay you alter the control surfaces in to a climb. You should be clear of the balloon. (Someone says that the kit to do this exists already.)

        2) You drop the aircraft with a weighted tail so that the aircraft drops tail first. (like a tail first stall.)

        After a calculated delay, you start the engines which also removes the excess weight on the tail.

        (Dry ice maybe?) This should launch the aircraft at a high angle but it should miss the balloon.

        3) Look back at some physics of a rotating arm and the atlatl. At launch the arm and aircraft are parallel to each other hanging straight down. At launch, the arm swings the aircraft on an arc. You can calculate the length of the arm based on the size of the balloon. You can determine the launch point and use a small explosive bolt to release the plane from the launch platform. The engine ignites some time after detaching from the launch arm.

        The key to #3 is that you need to have a strong flexible arm. My suggestion is a graphite pole like you see in a golf club. You also need an explosive bolt to aide in the release. And you'd have to deal with the timing of the release. (mercury switch or something...)

        This allows you to have 1 balloon and a relatively simple launch platform. Also easier to test the components like the detaching bolt, and also ignition tests on the engine. You could also preset the launch altitude too.

        But what do I know?

        I'm not a rocket scientist. :-)

      6. Marketing Hack Silver badge
        Black Helicopters

        Would it be practical....

        To plant a charge/valve of some kind ON the ballon, have that charge/valve detonate at the proper launch altitude and have LOHAN fire its engines a split second after the detonation of the charge/valve? It seems to me that the ballon would immediately vent all its gas at PARIS-launch altitudes, contracting to nothing and clearing the way for LOHAN to launch without the need for a boom and counterweight. At the same time, the parachute would barely deploy in the thin air at that altitude, so LOHAN would fly upward past the now tiny balloon and partially deployed chute.

        The trick would be making sure that LOHAN went upwards after the ballon goes pop, but I imagine there is some kind of gyroscope or something that can assure that.

        Black helicopters, because I design those for the UN, oil industry and the global investment banking cabal in my off-time. Wait...did I just post that on an open forum?? Damn!!, now they'll assign me a single digit number and pack me off to the village!!

      7. Pat 4

        Pop?

        Cant you just pop the balloon as soon as you have ignition?

  3. Craig "Spuddleziz" Smith
    Boffin

    How about?

    putting the launch payload at the top of the balloon and having a stabilising weight at 15m below it?

    Like this? http://www.clicknetworks.co.uk/balloon.png

    Please forgive the crudity of my model, mspaint isnt my storng point.

    1. Mike Richards Silver badge

      payload on top

      Is that even stable?

      Maybe the nearest aerodynamicist can put me right, but wouldn't a weight on top and a weight on the bottom just mean that with the slightest disturbance the balloon rolls over until the two weights are more or less horizontal?

      1. Stoneshop Silver badge
        Boffin

        @Mike Richards

        No, they will arrange so that the center of gravity will be below the center of lift, which is not necessarily horizontal.

        But the balloon is not stable enough to do that. If the weight on top shifts or the entire setup starts to lean over because of wind, the balloon will try to pop out from underneath, amplifying the shift.

  4. ewan 3
    Go

    Cut the string at a predetermined point

    Could you have the string to the ballon cut at a predetermined point (either timed, or by pressure - bladder expands an closes a pair of scissors or something!)? Then have a 5 second delay for the ballon to shoot off by itself, and then launch?

    Obviously you'd need to shape / weight the payload so that it fell in a stable way? How about an inverted cone of card with a weight in the end?

  5. kiwi8mail
    Go

    A shorter launch boom and...

    ... some sort of spirit level-type device (mercury switch?) on the launch arm.

    The launch arm will presumably see-saw around, and the exact moment of ignition should be set to only happen at an instant when the launchpad is tilting out from the centre (i.e not towards the balloon.

  6. Adrian Jones

    Does it have to be one balloon?

    Why not three balloons, arranged in a triangle, with LOHAN attached in a framework between them?

  7. Wokstation

    Could you not...

    ...could you not have the balloon under a cage of some-sort, with the launch platform atop it? Then use a counterweight to keep the balloon the right way up?

  8. Disco-Legend-Zeke
    Pint

    Perhaps...

    ...suspend the payload from the bottom to keep balloon upright. Rocket, fairing, and launching platform perched on top.

    The big challenge to this approach, finding an attachment method that accommodates the expansion of the balloon as it ascends.

    Maybe a mesh/string outer covering with the latex envelope freely moving inside. On the ground, the payload would hang well below, as the balloon expands, the payload would be drawn closer to the bottom of the envelope.

    Beer makes it clear.

    1. ArmanX

      That's what I was wondering...

      I'm unsure of how well it would work, but if the idea is for the LOHAND to get off without damaging her airbag, maybe she should be on top? Then again, if the ride is to rough, she may get smashed before she gets high enough...

      ...you know, I bet discussions about this project are VERY interesting to listen to.

  9. Dalen
    Boffin

    How about...

    ...placing the platform _on top_ of the balloon?

    1. Stoneshop Silver badge
      Thumb Down

      Those balloons

      are anything but stable, rather fragile, and increase a fair bit in size between ground level and launch altitude.

      Once you get around those three factors, a platform on top becomes viable.

  10. Wibble
    Holmes

    Long dangly; launch a couple of degrees off vertical

    Long dangly distance between payload & rocket - say 100M. Launch the rocket a few degrees off vertical to miss the balloon, say 80 degrees.

    You'll need to launch off of vertical anyway as you need to move to orbit (OK, you're not going to orbit, but think big:-)

    As the payload is pretty light, could use fairly lightweight line. Could have a stiff launch pole to ensure it goes in a straight line when you light the blue touch paper.

    Simplicity.

    1. Stoneshop Silver badge

      @Wibble

      Would it be feasible to hang LOHAN from the balloon using a short line (to minimise dangly-type problems during ascent), which at the point of launch is cut, allowing the launch assembly to drop, unreeling a longer line (your 100m sounds quite sufficient), the end stop of which triggers the engine ignition, with a few seconds delay to allow the launch assembly to stabilise vertically again. As always, the problem is keeping the mechanism from icing up.

  11. Bodestone

    Wingspan....

    Just a quick thought.

    If the plane was rotated by 90 degrees could you not knock the wingspan from the boom lenght?

  12. mccp
    Go

    Keep it simple, shirley

    Just release the rocket and allow it to fall for a few seconds before igniting the rocket. The chances of hitting the balloon - now rising faster - have to be pretty remote. Much lower in fact than the complicated multi-balloon/swinging arm contraptions simply going wrong.

    Assuming that both balloon and rocket are in the same air stream, most likely they won't travel horizontally at the same speed. Ergo, after a few seconds the rocket will be clear and bingo!

    Also gives you a chance to design a rocket that will fall in a vertical attitude but still glide down once the rocket propellant is all used up.

  13. Anonymous Coward
    Mushroom

    why not build a floating missile silo?

    Have the whole payload, including the vulture 2, sit in a tube suspended between 3 balloons (for stability). you can have the payload at the bottom for the whole way up, keeping the center of gravity in the right place until it blasts off. You could even mount a camera to the outside of the tube to get a very nice view of the launch.

  14. Thomas 4

    Submitted a design

    Inspired by equal parts Miss Lohan, Monty Python sketches and excessive caffine.

    1. andypbw

      Falling launchpad

      I was thinking this approach as well..... have a 2 stage launch process, where the bursting of the balloon (or the altitude release mechanism) allows stage 1 to freefall.

      Stage 1 has a simple parachute or wing to make it fall vertically.

      A few seconds later, stage 2 (the LOHAN rocket) fires.

      By this time, it is well clear of the balloon, and the launch platform is vertical.

    2. Martin 47

      seems good to me

      This was the answer I was thinking of, I suspect you will need folding wings though

  15. Pete 2 Silver badge

    The best counterweight

    ... would be another space-plane.

    Not only does this double your chances of success (and the cost) but you don't have to worry about the effects of a counterweight sized thing plummeting to earth in the even the balloon's parachute doesn't play by the rules.

    Plus, if the two planes' engines don't fire exactly simultaneously you have a nice bit of diversity in the trajectories.

  16. kiwi8mail
    Go

    A horizontal launch?

    Would it be possible to have a horizontal launch, with the spaceplane having crude control surfaces and guidance that can orientate it into a vertical climb within a few seconds of launch?

  17. Stoneshop Silver badge

    The horizontal spar and especially the counterweight

    will add a lot of weight.

    What about taking a long boom hanging down from the balloon, with the plane at the lower end of it. Halfway down the boom is a hinge point created from a bit of rope (a real hinge would ice up at altitude). A ring or disc just over the hinge blocks the lower end swinging up past right angles respective to the upper part. The plane hangs horizontally underneath the lower part of the boom.

    As the plane launches from the balloon it should initially stay attached to the boom which wil then cause it to swing from horizontal to somewhere near vertical, at which point the ring/disc blocks the boom from swinging further and the plane separates.

    The tricky bit is designing the attachment so that the plane is pretty securely coupled during ascent, holds during the swing, but separates easily once the hinge hits the stop.

  18. thag
    Go

    Alternatively...

    Since the vehicle is a space plane it presumably has wings and some means of roll and pitch control. Why not simply launch it at 45 degrees (or possibly less) from vertical to clear the balloon envelope and then pitch to vertical? You could either use an accelerometer to determine time to pitch up, or simply do it on a timed basis. Experiments at ground level might be useful if you've enough dosh for the rocket motors.

    1. frankgobbo

      Changing pitch

      Unfortunately I think this is a bit more complex than they're going for. I could be wrong, but to do what you're proposing you'd need hydraulically controlled wing flaps, etc.. I think that's probably outside the scope of this project.

      It'd be great if it wasn't but.. yeah :) This one strikes me more as a 'fire at the sky and see what happens' experiment

      1. thag

        @frankgobbo

        No, all you need is a couple of micro servos available from any radio control hobby shop. I'd suggest a delta design with control surfaces configured as elevons to save weight. Keep the servos inboard in the warm and use appropriate pushrods.

    2. Cliff

      I like this

      and not in a facebooky way, but in a real way - and it doubles the chances of finding some remnants too :-)

      1. Jolyon

        Double re-entry?

        No reason LOHAN couldn't handle that, I suppose.

    3. nyelvmark

      @Stoneshop

      This idea is interesting, I think. But did you confuse "horizontal" and "vertical" in there somewhere?

      1. Stoneshop Silver badge

        @nyelvmark

        The "horizontal" and "vertical" refer to the attitude of the plane, not the boom

  19. Jonathon Green

    Stabilising drogue on the main payload and delayed launch.

    Nothing wildly sophisticated, just a small parachute or a l-o-n-g ribbon.

    Release the main payload as a single lump and deploy the drogue a couple of dozen metres *above* the desired launch altitude.

    Deploy Vulture 2 (with intrepid Playmonaut) a few seconds after seperation when the balloon is well out of the way and the payload has had a chance to (more-or-less!) stabilise itself under the drogue.

    Optionally jettison the drogue (to avoid the main payload module drifting too far) and then deploy the main 'chute later as per normal for recovery.

    Yes it's a little bit more complicated than just lighting the blue touchpaper while suspended from the balloon and "wastes" a few metres of altitude but I reckon it's going to be simpler, lighter, and more compact than any of the alternatives which have been mooted so far and no more complex than some of the stuff which people are already doing with multi-stage rockets in amateur rocketry.

  20. Aaron Fothergill
    Mushroom

    what about a Parabolic Missile Slingshot Launch

    or PMSL? Vulture 2 is held *horizontal* under the balloon at the end of a 5 and a bit m long lightweight pole which is hinged at the balloon attachment and with the Vulture set to detach from it once it's vertical (a simple switch tripped by contact points on the pole and balloon at the hinge would be an easy way to trigger the relay).

    If you want to really try and be clever, you could fix some extra booster rockets to the Vulture end of the arm to assist in the Slingshot so Vulture 2 is already doing a decent rate of knots by the time the pole gets to the horizontal.

    One possible issue would be in high winds as you get higher, the pole could be flung around a bit, but having extra weight (or the main payload) suspended from it to be dropped away before launch could be a solution.

  21. James Pels

    hang it out the side...

    Something like this...

    https://www.eventelephant.com/ee/images/event/8578/lohan.pdf

    Obligatory use of sticking material, obviously (and it might even work!)

    If spinning is an issue, a few lightwight hoops holding the three suspension ropes (red and green) wouls stop them twisting.

    the line supporting the launch rail will always ensure Vulture 2 points a little outside the envelope, no matter how much it inflates.

    J.

  22. b166er

    How about

    3 balloons on the points of a large triangular frame/ring, with the vehicle slung centrally slightly below? Launch LOHAN through the ring fnarrr!

    1. Alfie
      Windows

      this isnt the title you are looking for

      You mean like some kind of inverted trebuchet? Or use an actual inverted trebuchet with the main payload as the counterweight in the system? Trebuchet assisted ballocket! Now were talking!

      ^ Mad Scientist

  23. TeeCee Gold badge

    The answer is in the question.

    "Call the total 5kg maximum"

    Given that the counterweight must either equal the weight of the spaceplane, or be on a far longer boom itself (adding weight both in the length of the boom and the increased need for strength in same) the answer's there.

    If you can't see the entire spaceplane assembly[1] clocking in around 2kgs or less (allowing a kilo for the boom, other bits and some contingency), this plan's dead in the water.

    [1] i.e. Glider bit, rocket bit and retention / release mechanism.

  24. Camilla Smythe Silver badge
    Boffin

    Oooooo Oooooooo Ooooooooooo

    Place plane inside Balloon...

    http://img8.imageshack.us/img8/2638/inballoon.png

    See

    Bit of elastic band type tethery stuff to hold it in place and give it a gentle ride up. Sums to be done so the ones connected towards the top carry the load and do not distort the balloony thing too much. Added lump of something underneath to help out. [with cameras and shit for extra piccies and stuff]

    When it is time to launch.... Cut the front elastic band and, if that does not burst it in the right spot, get PlaymoNaut One [Two] to smack a .22 round up the top end of the Balloon.

    Now your Balloon explodes from the top and the cunningly placed tethers assist in removing the latexy stuff from the vertical launch area whilst giving upwards impetus.

    4.03175624517 milliseconds later the rockets fire burning away the tethers and 'up she goes'.

    I'll just pat myself on the back whilst you go an implement it.

    1. Disco-Legend-Zeke
      Pint

      4.03175624517 Milliseconds

      +/- one MS

      BOFH rule #372: Always state results with three or four more digits of precision than the original data.

      A pint for you, mate.

  25. Pirate Dave
    Pirate

    Crazy idea

    put the vehicle inside the balloon and use some sort of sensor so when the balloon pops, the rocket engine fires. So then you only need some sort of ballast hanging from the bottom of the ballon to maintain orientation until the pop, at which point the vehicle and a minimal launch pad is (hopefully) still pointing upwards for long enough for the engines to ignite.

    This assumes the neck of the balloon can stretch enough for you to wiggle the vehicle+pad into it. I'd think since the balloon body can stretch to 30m, the neck should be able to stretch a few inches.

  26. breakfast
    Mushroom

    Two ways around

    I like the idea of three balloons with a simple pipe between the three of them, up which the rocket is launched.

    Alternatively could one performe some kind of hack involving a guidance wire attached to the outside of the balloon ( or even not attached, just long enough that it is displaced as the balloon expands, and set up so it doesn't pierce the side ) that the rocket plane could simply travel along during it's initial launch?

    Also, most of us are more interested in how to launch the Vulture 2 aircraft from beneath HYDROGEN-filled funbags. Hence the icon...

  27. Aaron Fothergill
    Mushroom

    Plan B. Rubber of Fantastic Length..

    Balloon has 10,000ft long bungie cord attached with Vulture 2 on the other end. When Balloon is at 30,000ft, launch team finally lets go of Vulture 2 and hey presto, perfectly vertical launch, no rocket boost required.

    1. Jolyon

      Plan B. Rubber of Fantastic Length..

      Co-incidentally that's also the proposed title of his next album.

  28. Hodders
    Pint

    How about..

    Multiple balloons attached to the circumference of a largish light (carbon fibre?) disk that acts as a launch pad (firing up through the balloons)

    Attach the main payload some distance below the disk which to act as a stabiliser

    1. Stoneshop Silver badge

      Not a disk

      That would add unneccessary weight. Just a circle, with the launch platform centered in the middle with nylon wire arranged in a spoke-like fashion.

  29. Jolyon

    LOHAN's briefs

    Where would I find a clear summary of the project goals?

    As things stand it just looks like PARIS with a rocket up the backside which, although clearly an interesting idea, might not be the great leap forward for Vulturnautics we ought to be looking for.

    Is a 2m wingspan necessary? Or could we return to (somewhere in the vicinity of) the launch site with small control surfaces, precision guided munition style?

  30. Sean Baggaley 1
    Thumb Up

    If placing the vessel inside the balloon isn't an option...

    ... and it probably isn't, as I suspect that would require a custom-made balloon, then how about this:

    Your article's diagram shows a boom slung beneath a single balloon. Why not invert this and use two balloons connected by a wide boom instead? No need for a counterweight either. The sheer size of the balloons—and the fact that there's two of them—reduces the problem of twisting of the balloons as they'll be more likely to cancel each other's movements.

    The launch vehicle sits in the centre of the boom directly above the payload, with its wings at 90º to the boom. This reduces the space needed to clear the balloons right down to the size of the fuselage ± 25% or so as a safety margin. (It's quite windy up there after all.)

    The boom only needs to be strong enough to support the weight of the payload + vehicle, as well as the forces applied by the balloons and winds during ascent.

    To save some weight, you could use the vehicle itself as an integral part of the boom's structure, but with the counterweight no longer required, this might not be necessary.

    Note that this also means the boom will always be angled correctly for the rocket-propelled vehicle to fly between the two gasbags, even if their heights aren't exactly the same. As the vehicle is to include its own autopilot, this can be programmed to apply automatic compensation after a second or so, ensuring it's cleared its Bulgarian launch platform before making any movements.

  31. This post has been deleted by its author

  32. stupormundi
    Boffin

    You're doing it wrong.

    I can't quite remember which cyberpunk novel I read this in, but isn't the point to swing the rocket back and forth (high five, FORTH fans!) under the balloon until the angle for takeoff is about right?

    Swoosh - swooosh - swoooosh - swooooosh - pfffshhhhheeeewww!

  33. Anonymous Coward
    Anonymous Coward

    Three balloons won't work

    Because you can guarantee that all three won't explode at once. As soon as one pops, the whole frame will drop and the spaceplane will be pointing at the horizontal rather than the vertical.

    1. Jolyon

      You can launch the rocket before any balloon pops

      Or at least you can make a reasonable effort to do so.

      Any plan that involved waiting until the balloon has burst before firing the rocket would have all sorts of issues - where's the balloon at that point? What direction is everything facing? What direction is everything moving?

      My instinct is that anything relying on being able to tie the launch in with the balloon burst is attempting to be too clever for its own good.

  34. Mr Young
    Happy

    I got an idea)

    Put a wee sharp pin on the nose then the rocket power device can simply fly straight through the exploding balloon in a few milliseconds? Playmonaut might need some simulator training but I think it might work ok

  35. Will 28
    Mushroom

    Coat the balloon in something highly flammable...

    Then the rocket firing will ignite and destroy the balloon... and possibly the plane as well. You could even fill the balloon with Hydrogen rather than Helium to really go off with a bang! LOHAN launches like a pheonix from the flames.

  36. Anonymous Coward
    Thumb Up

    simplest solution

    the simplest solution is to make the aircraft smart enough to handle getting away from the balloon, launching from near horizontal then going vertical after a predetermined time.

    It's like the difference between carburetion and fuel injection. One is mechanical, fiddly and has performance or reliability issues when subjected to widely varying conditions. The other, while more sophisticated electronically, is mechanically simpler and can be made to handle more strange conditions.

    Make the bird smart enough to handle it's course under burn AND descent, and leave less up to chance.

    1. M Gale

      ^^this

      If you're putting a guidance system in, you might as well go the whole hog and have it control the ascent as well as descent.

      Also about the weight, I know UK rules state you can have up to a 3 metre wingspan and 7.5Kg total weight (and I think that doesn't include fuel either) before you need a license. Much larger models can be built if you're willing to (or have a pilot who can) get certified for the vehicle you're building. Dunno what the rules are in Spain but I suspect they are less strict than a soggy, heavily-populated island off the North edge of France where you would probably hit somebody with a firework on a stick, let alone an amateur sub-orbital missile.

  37. philby

    one balloon, rigid triangle frame

    hang a triangular frame, approximately equilateral, under the balloon.

    Attach it to the balloon by one vertex, lower triangle edge to be horizontal. Rocket on one side, counterweight on the other side.

    Similar to original Register idea except a single beam attached to string at the center is never going to remain horizontal

  38. Dyspeptic Curmudgeon

    3 balloons or 1

    Using 3 balloons and a 'tube' through which the LOHAN launches, would mean a very large tube! You could instead have a reasonably small carbonfibre tube, held vertically between the 3 balloons, with the LOHAN mounted on the top...head on a pike style. The whole thing is stabilized by having the rest of the payload hung from the bottom of the tube.. Pro: Results in vertical launch Con: Needs 3 balloons and careful bracing to support the tube at the right place. Probably would need some sort of net around the balloons to attach the tube to, and a very long tube...-> extra weight *But 3 balloons gives greater lifting capability. Launch will likely destroy the balloons. If one explodes prematurely, the remaining 2 might just support the weight, albeit at an angle. Complex and difficult.

    Better:

    Use one balloon and a very long tether, so that the launch package is far enough below the balloon that the launch can be substantially vertical. The balloon subtends just under 20 degrees from 30 metres (Asin 10/30 = 20 degrees), Use 2.5 mm Dyneema line which has a 1600lb tensile strength at only 150gm per 30m (see http://www.apsltd.com/c-1492-amsteel-blue-samson.aspx for an example). Launch the LOHAN from a tube, tilted 15 degrees from vertical. The payload at the bottom of the launcher stabilizes the orienation (except for spin). Using a pipe removes any need for a release mechanism: just fire the rockets. The interior of the LOHAN can have a circular double helix structural spar up the middle, like the 3D-printed nylon plane from a few days ago. Use a carbon fiber tube for light weight and stiffness epoxied into the payload box at the correct angle. Suspend the payload from a bridle to ensure the correct orientation.

  39. Eddy Ito Silver badge

    Curved launch rail

    Once you have all the weights down it should be fairly easy to calculate the shape of a curved launch rail that would carry LOHAN aloft in a horizontal position and utilize the centripetal force generated by rocket against the curved rail to swing the rail to a vertical, or nearly so, angle of launch. The rail itself should be fairly simple. The problem will be calculating what is the optimal angle to built into the rail and what the radius of curvature should be. It would also be a good idea to calculate how big the errors can be and still get a good launch.

  40. Spider
    Thumb Up

    keeping it simple....

    Booms and counterweights seem like such a waste of scarce payload. In order to maximise the available angle of dangle why not extend the support line ? Simply hanging lohan 30m or more beneath her magnificent globe seriously increases potential launch angle and clearance to the aforementioned globe as shec thrust skywards. Keeps the load mission critical.

  41. Camilla Smythe Silver badge

    Oooooo Oooooooo Ooooooooooo Two

    Yes..... have to admit the other one has problems in that the tethers would not allow the ballons envelope to expand properly. Back to the drawing board and...

    http://img695.imageshack.us/img695/6340/balloon01.png

    http://img683.imageshack.us/img683/3998/balloon02.png

    http://img4.imageshack.us/img4/7361/balloon03.png

    See? Now the planes forward fuselage pokes through the balloon filling nozzle. Zoon in on the other piccies and a collar C, perhaps with some glue stuff clamps and seals the balloons neck around the fuselage. Just above it rubber O-Ring A pulls the neck into a cunning groove in the fuselage. At the bottom of the cunning groove there is a sacrificial loop of heating wire....

    On reaching the required altitude PlayMoNaut fires .22 cartridge at top of Balloon. Balloon explodes from the top peeling away from the vertical launch window. 2.31256mS later huge current is passed through the sacrificial loop of heating wire vaporizing it and cutting the neck and remainder of the Balloon from the fuselage at which point the rockets are burning and up she goes.

    Sorted... You can run some ground tests to prove I am right..... or not.

  42. Camilla Smythe Silver badge

    Oooooo Oooooooo Ooooooooooo Two.. Continued

    Having sorted out that problem, mumble mumble mumble.. Might need to think about other time balloon destruction in order to ensure the wings are cleared from possible balloon debris.

    Here is a plane of two parts.

    http://img708.imageshack.us/img708/8498/plane01.png

    and some other bits..

    In order to facilitate assembly of the plane and in particular the entry of the fuselage into the balloons latexy orifice make it in two parts. The mission package and the the wings/other bits. Now you can slip the mission package in, PlayMoNaut included, and strap them down before clipping in the back end; wings, batteries, rockets and other stuff.

    Note.... bullet in nose. :-) Want!

    Cameras running as PlayMoNaut is lofted to great height cocooned in his/her balloony latex womb getting bigger and bigger until, with PlayMoNaut smile fully extended in anticipation, they finger the trigger on the appropriate joything... BANG!

    Balloon parts above them revealing the heavens to the cameras as the balloon is separated, the rockets kick in and they soar into space.

    'Spectacular'.

    Regarding altitude measurement... Snore.

    Zooming in we have ITEM D,

    http://img62.imageshack.us/img62/7485/plane02.png

    It is meant to be a differential pressure measurement thing with one side connected to the inside of the Balloon via the Mission Package and the other side connected to the atmosphere via the Back End.

    It is left as an exercise[1] for the student to determine whether the modulus of something in the Balloon will result in a pressure differential compared to atmospheric at any particular altitude that will both give an indication of altitude and possibly impending Balloon destruction thus facilitating a launch decision.

    [1]Sounds good to me but I do not have a clue.

  43. Camilla Smythe Silver badge

    Seating Arrangement

    May I suggest..

    http://img534.imageshack.us/img534/2701/seating.png

  44. Old Man - Grey Fleece
    Flame

    Solve 2 problems at once

    Suspend LOHAN horizontally below baloon, have the rocket jet aimed at the string. (That's just a question of having the rocket forward and above the suspension point). Ignite rocket, as LOHAN starts it swings on the end of the string till it is pointing upwardsish at which point with a bit of luck the string burns through.

    Does require using just one rocket but two will be a disaster - different ignition times, different burn rates and different out of fuel times almost guarantees an erratic flight path.

    I think this solution bundles an unreliable release mechanism with dodgy orientation at launch but it is cheap.

    Flames icon for that powerful rocket effect.

  45. M Gale

    Howzabout...

    ...make the entire aircraft able to fit inside a drainpipe as the upper stage of a missile-like launch vehicle? The wings could pop out on a nice strong spring once the rockets are exhausted, with elevons at the back being used as aerodynamic control surfaces.

    As for missing the balloon, I reckon whatever guidance system you're using should take care of that. Some small control surfaces set into the first stage exhaust stream should give you enough manouverability to go from a horizontal to near-vertical flight path. If you can make a movable rocket nozzle (or just a tube) durable enough to last a few seconds then go for that instead. By the time any second stage kicks in (if indeed there be a second stage), you're probably going fast enough for the Vulture 2's elevons to be used as canards to maintain a generally upward direction of travel. So long as your guidance system can tell ground from sky (I'll give you a clue: the ground is generally warmer than the sky), the end result should be much more reliable than simply mounting it at an angle and praying the wind doesn't blow it too hard.

    Of course, test at a low altitude on a small scale with little C class engines or therebouts before sticking some whacking great Ms in the finished article. I'm no artist but if I can get something scrawled together I'll email some sketches.

  46. E-Penguin

    Really Long Fins

    are what's needed then. No complex control surfaces or accelerometers. Drop the plane horizontally, light the 1st stage and let the long fins shift the centre of aerodynamic pressure back far enough for it to stabilise in a vertical attitude. Jettison the Really Long Fins with the first stage.

    There should be plenty of air still about at 196 brontosauruses up.

    Actually, what we're after is a lot of drag, so maybe use feathers, like the object used to play badminton. Seems only right for LOHAN to ride a big (shuttle)cock...

  47. Jacqui

    two baloons and a launch rail/pipe

    Two "funbags" and a launch rod - Ooo Errr :-)

    Come on guys, you have to implement that design if only for the carry-on style comments it could lead to - it may not the simplest or most elegant but it has to be the most fun.

    Also could you get the reg logo on the baloons this time?

    Finally why not invite some of the people who photograph shuttle launches etc. The more pics the better.

    Jacqui

    Actually thinking about it the design can be quite elegant and would reduce spin.

    The payload could be used to provide the 5deg offset and a light CF frame could be used to ensure the baloons are kept well apart.

  48. Stoneshop Silver badge

    Do we have images of meteo balloons popping at altitude?

    Because I'm not entirely convinced that launching when the balloon goes kablooie is a bad thing. It's an easily detectable event (loss of pull on the connecting line) and it guarantees you're at maximum altitude. Risk of encountering balloon debris depends on launch timing and angle.

    What I see in videos I found is that the (party) balloon rips, but most of the time there are few if any loose pieces flying off. If meteo balloons pop the same way I'd expect LOHAN to be pretty safe from encountering scraps.

    Also, if you were to launch 45 degrees up (with subsequent trim to near-vertical) I doubt there would be balloon parts in LOHAN's way anyway.

  49. nyelvmark
    Boffin

    A possible solution

    ...has been suggested by at least 2 posters, which doesn't require a supercomputer to be part of the payload. Here is my back-of-a-beermat sketch:

    http://nyelvmark.net/lohan1.jpg

    Apologies for my poor skills in The Gimp, which said "Try holding shift to draw straight lines". When that didn't work, it had no further suggestions.

    1. M Gale

      It's quite an impressive sight

      http://www.youtube.com/watch?v=0lG3zr0yaJw

      Basically a big expanding, rising cloud of fine debris. I don't think it's anything to worry about given a sufficiently long line separating the launch vehicle from the balloons (or clusters of balloons from each other).

      That video is why I was asking for cameras pointing up from the launch platform. Could look even better from close-up.

      1. Camilla Smythe Silver badge

        Nice..

        Also,

        http://www.youtube.com/watch?v=mG7xFt1FpCc&feature=related

        in both cases it looks like 'the neck' survives so in my scheme at T- 3.09345678mS chop the neck from the fuselage. Balloon separates and lifts upwards whilst plane descends a bit. At T- 0 fire the bullet.... I'd like to swap the .22 round for grapeshot in a blunderbuss... vaporizing the balloon rockets are ignited and up she goes.

        http://www.youtube.com/watch?v=dYny82TfN0E&feature=related

        Ensure your oral cavity contains no liquids or other consumables.

        Interesting, snore, to see the pendulum dynamics of things. The balloon is catching the breeze and 'violently' jerking the 'load' about. Probably not much mileage in that one but something to think about.

        Wet finger in the air says the latex has become brittle at low temperatures and that is why it gets smacked into ittty bitty lickle pieces.

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