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back to article Teflon slips smoothly over LOHAN's mighty rod

Our audacious Low Orbit Helium Assisted Navigator (LOHAN) project is advancing rapidly on multiple fronts, and as well as mission control boards and fantastical flying trusses, we've been able to dedicate some time to the icy issue of the controversial Vulture 2 launch rod. Click here for a bigger version of the LOHAN graphic …

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Coffee/keyboard

I think you've earned your bank holiday beers thanks to "The grease and Teflon are more slippery than a lard-rubbed Spanish politico wallowing in a tub of eels".

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Silver badge
Boffin

Just a thought ...

This gadget is going to be blowing around and swinging about quite a lot on the way up. Are you sure it isn't going to swing far enough to tip the rod to facing downwards, so that the mighty Vulture 2 slips ignobly off the end?

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(Written by Reg staff) Silver badge

Re: Just a thought ...

I don't think so. The way the tethers are attached means it should keep its attitude of 20 degs from vertical, although it's certainly going to take a pasting.

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Headmaster

Units or you nits?

"It's merely for illustrative purposes, and is therefore neither to scale, nor an accurate reflection of the final design of the Vulture 2 and its exact position under the truss."

"LOHAN regulars will note we've reduced the size of the aluminium plate behind the spaceplane..."

No we won't! See first quotation.

Good luck!

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Any chance of an overall progress update / review?

See title...

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(Written by Reg staff) Silver badge

Re: Any chance of an overall progress update / review?

Yes. I was thinking myself that a state of play round-up is in order. I'll get on the case next week.

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Thumb Up

Top shedding on the lumps of ice problem!

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(Written by Reg staff) Silver badge

Shedtastic stuff indeed ;-)

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Anonymous Coward

mighty rod

To describe LOHAN as having a mighty rod is gross.

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Re: mighty rod

Think of it like this instead -

LOHAN will be sliding on and off a well lubricated mighty rod.

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Cold, thick grease

Although the grease may well prevent the icing, how much resistance will it present when at -60C? Although I have no doubt that everything will still be free to move, will a good chunk of the engine burn phase be taken up just pulling LOHAN off the greased up pole?

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(Written by Reg staff) Silver badge

Re: Cold, thick grease

The point of the grease is that it's good to -73 degs C. At -20, it didn't demonstrate any increased viscosity, but we will test it at lower temps.

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Datasheet

According to the datasheet for the grease at -73'C:

Initial Break-away Torque, (Nm): 130 x 10 -3 [This is copied and pasted, I know the number format is not correct]

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Ru
Paris Hilton

Why an unsupported rod?

I'd have thought something like these (sorry; couldn't find a noncommercial link at short notice) supported rails would have formed a more stable, solid platform. Making a suitably robust bearing sleeve to stop the plane jamming or falling off doesn't seem like a massive difficult task. Hell, you could have two rails and a lightweight launch carriage (to prevent racking).

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(Written by Reg staff) Silver badge

Re: Why an unsupported rod?

We've been over all of this before. We're going with the titanium rod and our inserts.

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Ru

Re: Why an unsupported rod?

Well yes, obviously that's what you're going for.

I've evidently missed the explanation of why though.

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(Written by Reg staff) Silver badge

Re: Re: Why an unsupported rod?

Here's why: it's the simplest solution, which is the way we like our solutions. I can't honestly see any problem here, or why we'd need rails/guides/whatever. A 10mm titanium rod around 1.5-2m long is not going to buckle/wobble/break, even at -60 degs C.

As LOHAN regulars know, we do take readers' advice on board, but someone has to make the final decision, otherwise we'd be debating every minute detail of the mission until the cows come home.

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Anonymous Coward

LOHAN could be doing too much swinging....

Even with foam and teflon, LOHAN's wings could get damaged with all that swinging going on. Especially at -20 the foam probably won't be that soft.

Maybe the teflon could be brought down on either side to just a few mm above the wings, so that there's less room to swing. Still enough room to get a bit of swinging going, so nothing gets stuck, but not so much that any damage can be done.

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Bronze badge

Re: LOHAN could be doing too much swinging....

I've suggested that twice before already. It seems to have been ignored so far.

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(Written by Reg staff) Silver badge

Re: LOHAN could be doing too much swinging....

Yup, the actual distance between the wings and the Teflon strip will be minimal.

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(Written by Reg staff) Silver badge

Re: Re: LOHAN could be doing too much swinging....

It hasn't been ignored. We've done updates on reader suggestions, with launch rails included. After consideration, we decided to go with our simpler plan.

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Childcatcher

Re: LOHAN could be doing too much swinging....

You are suggesting that we limit the extent of LOHAN's pole dance?

Tut tut.

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Should have read

TEFLON SLIPS SMOOTHLY OVER LOHAN'S MIGHTY LUBED ROD

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Bronze badge

Re: Should have read

Or "Teflon Inserts to help LOHAN off the pole

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Windows

Looks more slimy..

Than a Coalition Politican!

Lovely Jubbly!

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Solid body rotation when the motor fires

Slippery indeed. I'm worried that because the thrust vector of the motor doesn't point through the center of mass of the complete truss/vehicle, when the motor ignites, even though there is minimal friction between the teflon and the rod, the resulting moment will cause the complete truss/vehicle assembly to rotate. Of course LOHAN won't be on the rod for very long, but there will still likely be enough rotation to mean LOHAN potentially goes straight up into the balloon.

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Bronze badge
Windows

Re: Solid body rotation when the motor fires

Think that was the reasoning for the (IMHO) very smart decision to add a vane to the truss' tail. I think that'll give it enough stability to ensure that, when the LOHAN finally farts, the truss will be stable enough for enough time that it'll be irrelevant.

(Given the very reduced air pressure up there, I'd have gone for a couple of those Holy Bricks in previous pics. for stability, but the lads at SPB know what they're doing)

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Coat

Beyond

This whole LOHAN project has so faaar left the garden shed and basement lab. No more amarteur PARIS sucking on straws but prof LOHAN taking on big rockets. Next, NASA will be on your sponsor´s list. I´m out of here.

´

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will it fly?

Any news on the plane itself? And any plans for a test glide to check out the autopilot before the big day?

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(Written by Reg staff) Silver badge

Re: will it fly?

The Southampton lads are beavering away. We're mulling a test flight...

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Meh

Icing paranoia

Out of 180 high altitude balloon flights, the only times when we've encountered icing problems is when flying through low-altitude clouds, where the dew point was just a tad above freezing. And except for the one where we launched in pouring rain (a rarity in Colorado!), the only icing we observed during ascent was frost on the camera viewport glazing. This is because the latent heat in the materials kept the temp high enough to get us thru those risky regions, In the rainy case, our mechanical burst-sensing release mechanism did indeed freeze up and brought the shards back home. So rather than deal with the risks of excessive viscosity of lubricants, I'd recommend simply not ascending through clouds. Which I presume excludes launching from the plains in Spain :=P.

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