Author Topic: Fairing reuse  (Read 561611 times)

Offline Burninate

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Re: Fairing reuse
« Reply #180 on: 03/12/2016 02:03 AM »
Wild-ass guesses corroborated by nothing whatsoever:

The observed thrust is venting of the remaining pressure in an N2 pneumatic tank normally used in separation, associated with some safety procedure they're testing for Falcon Heavy, which will drop fairings (or perhaps interstage?) on a trajectory much closer to the launchsite in order to optimize RTLS.  They want the chance of ballistically dropping pressurized cylinders near population to be closer to zero than it is at present.

The cylinder is either a finished fairing at an angle, or a fairing spray/cure booth.  As mentioned upthread, fairings are delivered from overseas rather than manufactured in-house, but the center of the picture indicates they may not be painted when they get here.  Alternately, it's possible that it's an interstage or a stage that's simply suffering from some flavor of perspective distortion.
They make fairings in-house. Do you have a source for your statement that they aren't?

My mistake, I misread something a few pages back.
« Last Edit: 03/12/2016 02:04 AM by Burninate »

Offline sewebster

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Re: Fairing reuse
« Reply #181 on: 03/12/2016 04:28 AM »
Do they autoclave their fairings?  That would be a huge autoclave.

I assume they do? Aerospace autoclaves are rather large... Dreamliner autoclave is 9 m dia, 30 m long.

Offline kkellogg

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Re: Fairing reuse
« Reply #182 on: 03/13/2016 11:48 PM »
Any guesses about what the white curved structure barely visible in the extreme lower right of the photo might be? If it is not part of the building, it certainly is of a much larger diameter that anything else in the photo.

I think it's a tank section for either F9 or FH.

Offline CraigLieb

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Re: Fairing reuse
« Reply #183 on: 03/14/2016 02:49 AM »
Any guesses about what the white curved structure barely visible in the extreme lower right of the photo might be? If it is not part of the building, it certainly is of a much larger diameter that anything else in the photo.

I think it's a tank section for either F9 or FH.

I looked through as many of the building tour videos and pictures as I could find and didn't
See that in any of them.
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Offline dorkmo

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Re: Fairing reuse
« Reply #184 on: 03/14/2016 03:01 AM »
Any guesses about what the white curved structure barely visible in the extreme lower right of the photo might be? If it is not part of the building, it certainly is of a much larger diameter that anything else in the photo.

I think it's a tank section for either F9 or FH.

I looked through as many of the building tour videos and pictures as I could find and didn't
See that in any of them.

to me it looks like an interstage that has wiring on its exterior. what can be seen at the base looks like the holes for gridfins. not completely painted there. exterior wiring is a bit perplexing but makes me think its for a test flight which might mean heavy demo?

Offline iamlucky13

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Re: Fairing reuse
« Reply #185 on: 03/14/2016 07:31 PM »
Separation is done with pushers

I've always known it was done with pushers and I think N gas pushers but I'm surprised by the technology path they've chosen. I always assumed that they used COTS nitrogen gas springs of the type used in automotive lift gates or the type used in stamping dies.  In my scenario the halves would be held together with electrically releasable latches such as on car trunks.  I guess those assumptions show the field that I've been working in.  But also now see that if they'd have chosen the path that I envision there'd be challenges in bringing the fairing halves together evenly against the multiple springs.

Using a depressurized actuator, separate pressure reservoir, and a control valve can allow you to withdraw the latch pin without the push loads already on the fairing trying to bind up the latches.

The assembly problem of your idea can be avoided, however, by designing room for a retainer to hold the spring compressed in the right position until the latches are closed. Forgetting to do this with high force springs is huge pain the rear. Been there, done that, fortunately did not lose any fingers.

Offline CyndyC

Re: Fairing reuse
« Reply #186 on: 03/15/2016 01:09 AM »
         
« Last Edit: 03/15/2016 02:00 AM by CyndyC »
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Online meekGee

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Re: Fairing reuse
« Reply #187 on: 03/15/2016 01:56 AM »
         

An odd patent... (Low shock separation joint - US 7127994 B2)

Most of the spec is about a separation joint - nothing to do with a retained split fairing design...

Then there are these two figures at the end, seemingly out of the blue, a bit of text, and no claims related to this mechanism.

Sometimes you add text to prove the utility of the patent, but this doesn't look like it at all...

head scratch...

(And I doubt anyone can patent the idea of a retained split fairing anyway...  )
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Offline CyndyC

Re: Fairing reuse
« Reply #188 on: 03/15/2016 02:11 AM »
An odd patent... (Low shock separation joint - US 7127994 B2)

Most of the spec is about a separation joint - nothing to do with a retained split fairing design...

Then there are these two figures at the end, seemingly out of the blue, a bit of text, and no claims related to this mechanism.

Sometimes you add text to prove the utility of the patent, but this doesn't look like it at all...

head scratch...

(And I doubt anyone can patent the idea of a retained split fairing anyway...  )

Wow, how were you able to find the name and number? I came across it for a Biomimicry class assignment, and it seemed to fit the discussion here in a few & funny ways. Your doubts are not surprising since the patent has lapsed.
« Last Edit: 03/15/2016 02:12 AM by CyndyC »
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Online meekGee

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Re: Fairing reuse
« Reply #189 on: 03/15/2016 03:13 AM »
An odd patent... (Low shock separation joint - US 7127994 B2)

Most of the spec is about a separation joint - nothing to do with a retained split fairing design...

Then there are these two figures at the end, seemingly out of the blue, a bit of text, and no claims related to this mechanism.

Sometimes you add text to prove the utility of the patent, but this doesn't look like it at all...

head scratch...

(And I doubt anyone can patent the idea of a retained split fairing anyway...  )

Wow, how were you able to find the name and number? I came across it for a Biomimicry class assignment, and it seemed to fit the discussion here in a few & funny ways. Your doubts are not surprising since the patent has lapsed.

Google Image Search, click the camera, then can search by URL...  If using chrome, there's a direct right-click short cut.

The amount of riddles this has solved for me...
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Online wannamoonbase

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Re: Fairing reuse
« Reply #190 on: 03/18/2016 02:47 PM »
Anyone hazard a guess on how well retrieval would work during night launches?
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Offline Jarnis

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Re: Fairing reuse
« Reply #191 on: 03/18/2016 03:50 PM »
Anyone hazard a guess on how well retrieval would work during night launches?

Night vision goggles are fairly mature tech, as is flying in darkness with them.

Offline Rabidpanda

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Re: Fairing reuse
« Reply #192 on: 03/19/2016 08:59 AM »

Do they autoclave their fairings?  That would be a huge autoclave.

I assume they do? Aerospace autoclaves are rather large... Dreamliner autoclave is 9 m dia, 30 m long.

The fairings are cured in an oven, not an autoclave.

Offline sewebster

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Re: Fairing reuse
« Reply #193 on: 03/20/2016 05:33 PM »

Do they autoclave their fairings?  That would be a huge autoclave.

I assume they do? Aerospace autoclaves are rather large... Dreamliner autoclave is 9 m dia, 30 m long.

The fairings are cured in an oven, not an autoclave.

Thanks. Do you know how they apply pressure to the parts?

Offline Robotbeat

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Re: Fairing reuse
« Reply #194 on: 03/20/2016 06:11 PM »

Do they autoclave their fairings?  That would be a huge autoclave.

I assume they do? Aerospace autoclaves are rather large... Dreamliner autoclave is 9 m dia, 30 m long.

The fairings are cured in an oven, not an autoclave.

Thanks. Do you know how they apply pressure to the parts?
Perhaps they vacuum bag them?
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Offline sewebster

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Re: Fairing reuse
« Reply #195 on: 03/20/2016 08:39 PM »
The fairings are cured in an oven, not an autoclave.

Thanks. Do you know how they apply pressure to the parts?
Perhaps they vacuum bag them?

Yes, seems likely, but autoclaves are used in addition to vacuum to apply more pressure to reduce voids etc. Vacuum can only give you one atmosphere. There are other techniques for applying more pressure that don't involve an autoclave... https://en.wikipedia.org/wiki/Out_of_autoclave_composite_manufacturing

Offline Rabidpanda

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Re: Fairing reuse
« Reply #196 on: 03/21/2016 03:45 AM »


Do they autoclave their fairings?  That would be a huge autoclave.

I assume they do? Aerospace autoclaves are rather large... Dreamliner autoclave is 9 m dia, 30 m long.

The fairings are cured in an oven, not an autoclave.

Thanks. Do you know how they apply pressure to the parts?
Perhaps they vacuum bag them?

Yes, they are vacuum bagged.

Offline Stan-1967

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Re: Fairing reuse
« Reply #197 on: 03/21/2016 04:04 AM »
Rough numbers but you get the idea;

What's F9's payload capacity to GTO?  10,000 pounds?
What's the weight of the payload fairing?  5,000 pounds?
What's the revised payload capacity if you take the payload fairing along for the whole ride?  ?5000? pounds.

Substitute in actual numbers and you get actually poor numbers.  Weight carried on the first stage is not good.  Weight carried on the second stage is really not good.

Very poor numbers indeed.  Recall the Taurus XL vehicle that failed to jettison the fairing on the launch of the "Orbiting Carbon Observatory", and "Glory".  In both cases the vehicle failed to reach orbit.   

Offline Stan-1967

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Re: Fairing reuse
« Reply #198 on: 03/21/2016 04:47 AM »
         

Why not develop a fairing that peels back like a banana peel and locks against the second stage skin? Kind of like the legs, but in reverse.

It could be used as a TPS for the second stage so the stage can be recovered.

No need to peel it back if it is taken to orbit.  It could be opened right before spacecraft deployment.  But the fairing would reduce payload mass.

1.  Is there substantial advantage to recovering a fairing like in the schematic above as a single assembly, vs. trying to recover two individual halves?   The aerodynamics of the fairing re-joined together seem more suited to surviving & conducting a controlled reentry. 

2.  The fact that F9 fairings have been recovered, either in pieces or near complete halves, show that they are strong enough to withstand reentry.  However I don't see that the "halves" are going to be controllable during descent, which makes the condition they survive in questionable.

3.   If the springs in the schematic were mounted on the outside of that "interstage" looking attachment hoop instead of the inside, they could still be used to open up the hinged fairing.   (encasing the springs in an aeroshell/fairing of sorts)   If the mounting hoop that the fairing halves are hinged to has a larger inner diameter than the outer diameter of the second/final stage, you could slide the entire opened up fairing & mounting hoop down the side of the stage and jettison it at the rear of the rocket, into the plume of the accelerating stage.  It would have to have clearance of the payload pedestal & payloads, as well as any exterior plumbing on the side of the rocket.

4.  After the fairing halves & mounting hoop has slid down the length of the accelerating rocket, & is clear of the engine nozzles & associated gas plume,  you could close and lock the halves and have a very aerodynamic shape for controlled reentry and recovery.

Offline Jim

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Re: Fairing reuse
« Reply #199 on: 03/21/2016 02:52 PM »


2.  The fact that F9 fairings have been recovered, either in pieces or near complete halves, show that they are strong enough to withstand reentry.

It was pieces, which is standard for all fairings and not just F9.  Most just sink.  It has nothing to with strength or withstanding.
« Last Edit: 03/21/2016 02:53 PM by Jim »

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