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back to article LOHAN's fantastical flying truss takes to the air

We're pleased to report that last weekend the Low Orbit Helium Assisted Navigator (LOHAN) fantastical flying truss finally got off the ground, and we've got some video of the test for your viewing pleasure. Click here for a bigger version of the LOHAN graphic The plan, as regular readers will recall, was to see just how a …

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Silver badge

No beer necessary

>we had a bit of a lightbulb moment as to how to mount the Vulture 2 underneath the structure

Good job I read to the bottom because I was just going to suggest that.

You need two parallel rods, one going through each wing of the craft and something for it to shove off of. When it gets to the end of the rods it's on its own.

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(Written by Reg staff) Silver badge

Re: No beer necessary

You're close - so close...

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@Lester

Great minds and all that.

Maybe a few beers will help me get the full picture although I can' help thinking that to improve on my suggestion must involve more beer than I'm used to.

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Go

Re: No beer necessary

flat on the bottom as I posted last time: http://forums.theregister.co.uk/post/1325111

but the mount is the tricky part isn't it? shouldn't be too hard. Tracking & control sounds like a bigger challenge to me. I know they'll make it work. Lester seems up to the task.

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Re: No beer necessary

Does the rod need to go through the wing? Can the plane just sit on the rods, sandwiched between the bottom of the truss and the rods? If the rods are close enough to the fuselage, that should be enough to hold the plane straight and square as the motor fires.

Interesting either way!

Cheers!

Matto :)

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Silver badge

Re: No beer necessary

One rod.

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@Matto in AUS

>Does the rod need to go through the wing?

Not being privvy to the craft design the only other thing I can think of is if a hole through the wing would subtantially weaken its structural integrity then use tubes or eyelets fixed flush to the wing or possibly along the fuselage. Assuming the wings will be curved then the fuselage/tube or wing/eyelets seem more likely options.

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Re: two parallel rods

Ever since I saw the initial design with two parallel rods I have been wondering if that isn't a high risk launch option. There are several factors that could result in those rods not staying parallel during the course of ascent.

The rods being mounted on different parts of the platform structure 'could' result in either a convergence or divergence of the rods due to thermal changes and loading stress in the platform structure as it ascends into the colder regions of our atmosphere. This would effectively 'clamp' the craft between the rails during launch and wreaking havoc on the whole platform when the engine is ignited.

My suggestion would be to use a single rod and 'hang' the craft upside down on that rod. There is no up or down in space so the launch orientation is irrelevant.

Would hate to see this fail because it got stuck on the launch rails.

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@Reginald Gerard

The problem with one rod is that the craft might spin and the wing drag along the truss potentially causing damage. Another possibility is that during the ascent the wing remains in contact with the truss and freezes to it. Or if you really want to consider other possiblities there is nothing to say that the rod won't warp towards the truss and have the craft launch into it. This is still a possibility with a two rod solution however two rods require a shorter length than for one rod and so any warping will be less.

Furthermore I assume that the materials for the rods will be tested to ensure they don't warp too much at low temperature or if they did they would still be flexible enough that upon launch the guides would pull them back parallel.

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Happy

Exxxxxcellent news smithers

In the meantime however there is a far more pressing and important issue which needs to be resolved.

How exactly does one obtain a Special Projects Bureau T-shirt?

If there is no official channel then perhaps someone might be good enough to upload the logo so we may do our own (copyright permitting of course), because I really REALLY want a Special Projects Bureau T-shirt (yes I am that sad)

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(Written by Reg staff) Silver badge

Re: Exxxxxcellent news smithers

Well, since you ask... We did the design just for team members, but if you really, really want one:

http://www.cafepress.com/specialprojectsbureau

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Re: Exxxxxcellent news smithers

That's a great question - one other...

When will we get to see video of LOHAN and a donkey?

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Go

Re: Exxxxxcellent news smithers

You mean LOHAN & the Special Projects Burro? I'm sure that will rack up the views on youtube. LOHAN LAUNCHED OFF DONKEY!!! HOT LOHAN-Donkey ACTION, etc.

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maybe,..

... you could have a single point of lift but connect it to both ends, similar to this poor attempt at a diagram but with angles somewhere between 30-60° (you'd have to experiment for the optimal angle for stability

/ \

/ \

/ \

/ \

/ \

/ \

/ \

/ \

/ \

/ \

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

clearly i know nothing of aerodynamics, i'm just guessing :)

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(Written by Reg staff) Silver badge

Re: maybe,..

Yes. If we're going to incline the truss, we'll have to connect at both ends.

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Anonymous Coward

Why such a long truss?

I thought the long truss came out of the original "Twin Orb" concept; if you're going for a single balloon (or multiple balloons acting through a single point) why not minimise the length of the truss to lose weight?

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(Written by Reg staff) Silver badge

Re: Why such a long truss?

Yup, it doesn't need to be so long. Less is more, and all that.

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Holmes

Boffinry

Hmmmm. To be considered a true boffin, surely Katarina should sport a beard to go with the obligatory pipe?

Kudos to her for trying to clench said pipe in a suitably nonchalant way (but tbh she needs a bit of practice!).

Can't wait for LOHAN's departure into the great blue yonder.

<--- For the pipe, obviously.

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(Written by Reg staff) Silver badge

Re: Boffinry

"but tbh she needs a bit of practice!"

Hence the "apprentice" part of her job title.

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Facepalm

Re: Boffinry

<--------- I... am suitably chastised.

Red face, coat, exit through the closest door.

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Anonymous Coward

Shes obviously to young to have worn a pipe notch yet.

Don't be tempted to cheat by applying Dremmel to the teeth..

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Anonymous Coward

*Too

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Bronze badge

Re: Boffinry

I understand that the boffinry qualification test in the rocketry department has to include hydrogen peroxide and cardigans, Bonus points for Morris Dancing.

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Happy

Heading to North Africa

I'm keeping an eye out for it here in Gibraltar!

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TRT
Silver badge

Single cluster connected to one end by, say 5m ropes, to the other end by 8m ropes, rocket launched from a tube in the centre of the truss.

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Thumb Down

Tube?

a bit difficult to launch a winged craft from a tube

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Coat

"Heading for Africa"

Lest we be accused of resorting to imperialism again, maybe there should be a similar range safety system so you can remotely blow up any disastrous launches that may be interpreted by foreign nations as a pre-emptive strike :-)

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Launch gubbins

With LOHAN under the truss, some (longish) rails under each wing should hold her securely through the buffetting of the ascent, but provide little resistance when the rocket kicks in.

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Anonymous Coward

Re: Launch gubbins

"some (longish) rails under each wing should hold her securely through the buffetting of the ascent, but provide little resistance when the rocket kicks in."

You'd be surprised how these things can work fine on the ground, but not at altitude.The launch rails will be subject to icing and possibly thermal effects, so may not be exactly parallel at launch altitude.

To retain the rocket on a single rail I'd suggest a loop of fine fishing line through two small holes (pinholes really) in the exhaust tube; the line will have plenty of strength to hold the rocket in place but the engine will burn it away on ignition leaving the rocket free to launch.

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Paris Hilton

Ancilliaries?

How do you plan on mounting cameras etc on an inclined truss? I wondered if some kind of Spaceplane Launcher Utility Turret could be designed, they're not at all hard to mount.

Paris, for reasons that should be obvious.

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(Written by Reg staff) Silver badge

Re: Ancilliaries?

I suspect well be using those bicycle handlebar mounts to clamp cameras to the truss. Then we can swivel 'em to the required position.

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Boffin

Ah... Why not ditch the truss idea all together and simply have a box of some description with a small weight, like the battery, in the bottom. Maybe even a sphere or egg shape instead of a box.

Plenty of stability and aero without the inefficient truss.

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Here's my idea.

You want a vertical truss? simple - construct a horizontal triangle, attach a balloon to each corner, attach a wire from each corner of the triangle to a corner of the truss.

Dangle a weight from the bottom of the truss.

You could also have a cable from each corner of the bottom of the truss to the triangle to stop the bottom swinging - though news items mentioning LOHANs swinging bottom might be worth reading.

The triangle will have to be large enough to allow LOHAN to pass between the orbs of course.

OR

Similar to above but with one (or more) balloon(s) mounted above the triangle. truss could then be angled as needed by tightening one of the lower wires (bottom of truss to triangle).

ttfn

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Balsa Launcher Out Weighs Just Ordinary Balloons

Are you going to be relying on gravity to hold LOHAN to her truss?

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Re: Balsa Launcher Out Weighs Just Ordinary Balloons

No, of course not - just as in real life (tm) they're bound to use straps.

ttfn

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Real life? It'll never catch on.

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Paris Hilton

plane design

Just a couple of thoughts which popped into my head during a lecture on plane design. Why not have LOHAN as a bi-plane?

This generates additional lift without having overlong wings to worry about as well as allowing it to fly considerably slower which would be great for the on board camera.

It would also look awesome the playmonaught could even take a friend to play tennis with on the wing!

Paris because not only planes can be bi

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Headmaster

Re: plane design

Biplanes only generate extra lift if they're staggered. The biplane design improves strength rather than lift. Oh, and it certainly adds weight, which is not wanted here!

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Biplane? I think the rocket forces would rip the wings off... go back and re-read your history of aircraft in WWI and why the biplane's days were numbered. Something about excessive drag as I recall....

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Great

Now somebody in North Africa will think a UFO has crash landed.

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Alien

Re: Great

This is much more preferable than a Coke bottle...

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Spinning

The trouble with 1 balloon is the payload will spin and the video will be nausea inducing.

Why not have 2 balloons with lines from each going to both ends of the truss? This will keep the whole thing level and stable.

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