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LOHAN to straddle meaty titanium rod
Skirt lifted on cunning Vulture 2 launch plan
After much head-scratching, and a good number of beermat sketches, we're finally ready to unveil our concept for the Low Orbit Helium Assisted Navigator (LOHAN) Vulture 2 launch platform.
To recap, we've been pondering just how to attach our spaceplane to the carbon-fibre fantastical flying truss which will carry it heavenwards.
Last weekend, we tested a balsa wood model of the truss, to determine whether we'd be using one meteorological balloon or two mighty orbs to provide the mission's vital lift.
The conclusion was that a single globe is the way to go, and having decided that, we could then move on to the thorny problem of mating Vulture 2 and truss.
Yesterday, we had a round-up of some of your suggestions, and the general consensus was that somehow suspending the aircraft from a single launch rod is the best way forward.
Well, here's how we think that will work. Bear in mind this is just a concept graphic, and not a scale drawing:
Some points of clarification:
- The aluminium plate is bolted to the underside of the truss. The titanium launch rod is bolted through the plate.
- The Vulture 2 swings freely on the rod, which passes through the top of the fuselage.
- Where the rod passes though the fuselage, there are Teflon tube inserts, to minimise friction.
- A sacrificial rubber pad protects the spaceplane's rear end from damage during the ascent, since it would otherwise be resting on the aluminium plate.
- For obvious reasons, the Vulture 2 must have a "V" tail elevon configuration.
- The Teflon strips are mounted on foam rubber. They prevent damage to the wings if they swing against the truss on the ascent. They also act a low-friction "guides" if one wing hits the truss during lift-off.
- The electronics enclosure is a styrofoam box inside the truss, containing all the GPS gubbins, rocket ignitor system, batteries, etc.
Now, we can almost hear your keyboards clattering as you prepare your objections. Here's a list of pre-emptive answers to what we're sure you're poised to ask:
- We're sure that the titanium rod and aluminium plate will be strong enough to take the weight of the Vulture 2.
- The reason the spaceplane is allowed to swing is to prevent the most serious potential problem: the aircraft freezing to the rod. Our thinking is that the motion will keep the Teflon inserts unstuck. A low-temperature test of rod and inserts is certainly in order, to investigate how both materials will perform at -60°C.
- The rod passes through the fuselage at two points to prevent the spaceplane attemping to yaw during the ascent, which could potentially snap off a single mounting point.
- If necessary, we'll use a low-temperature grease to lube the rod. Again, we can test that at low temperature to see if there are any issues.
- We think that in the event of the Vulture 2 launching with one wing in contact with the Teflon strip, it won't suffer any significant damage. We can grease the strips if necessary, to prevent the wing freezing to the Teflon.
There's one final and critical feature of this set-up. We'll weight the truss so that it the event of premature balloon burst, it'll fall "nose-down". The Vulture 2 will simply slide off the rod, its weight breaking the rocket ignitor wires (not shown in pic), and it can then fly back to base, albeit without having fired its mighty thruster.
On the matter of the thruster, we know many of you are unconvinced the AeroTech RC 32/60-100NS is up to the job. Rest assured, we're exploring mightier alternatives.
So, it just remains to hand over the LOHAN Vulture 2 launch concept over to you, our beloved reader experts, for your opinion of our cunning plan. As you know, we always welcome intelligent comment and suggested improvements, so let us know what you think. ®
Further LOHAN resources:
- New to LOHAN? Try this mission summary for enlightenment.
- You can find full LOHAN coverage right here.
- All the LOHAN and Paper Aircraft Released Into Space (PARIS) vids live on YouTube.
- For our SPB photo archive, proceed directly to Flickr.
- We sometimes indulge in light tweeting, as you can see here.