Author Topic: SpaceX renovating former Falcon 9 test stand at McGregor  (Read 3356 times)

Online Chris Bergin

https://www.nasaspaceflight.com/2019/10/spacex-renovating-falcon-stand-mcgregor/

- By Ian Atkinson

Fans of the Tripod stand will be pleased :)

Thanks to Gary for taking his camera with him when out flying! :)


https://twitter.com/NASASpaceflight/status/1183804907679293442
« Last Edit: 10/14/2019 06:02 pm by Chris Bergin »
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Offline FutureSpaceTourist

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https://twitter.com/elonmusk/status/1183813898748563456

Quote
Yeah, will be Raptor vertical test stand. Hopefully allows simplification of Raptor design, as pump shaft wear & drainage is better in vertical config. Also, more representive of flight. Test as you fly …
« Last Edit: 10/14/2019 06:38 pm by FutureSpaceTourist »

Online Chris Bergin

Updated the article based on the Elon response :)
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Offline ZChris13

Very interesting article

Offline waveney

I wonder if they will use the Tripod to test more than one Raptor at once?  Three maybe?


Offline Prettz

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I never knew rocket engine wear and tear could be affected by the orientation it was pointing.

Offline Cherokee43v6

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I never knew rocket engine wear and tear could be affected by the orientation it was pointing.

Think of it like your car.  Wear is greatest when you are starting your car after letting it sit.

Now think about rotating parts that are intended to be positioned vertically and have the direction of thrust come straight through their vertical axis.  Now rest that spinning shaft on a bearing that would normally not have that weight resting on it.  So as it spins up more pressure is applied to that lower side and then as it spins down the same thing happens.  Thus more wear.
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Online Perchlorate

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Nice article!

"However, recent aerial images show that the stand is all but sitting idle."

Would that make more sense if it read:

"However, recent aerial images show that the stand is anything but sitting idle."

 :)
Pete B, a Civil Engineer, in an age of incivility.

Offline Lars-J

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I never knew rocket engine wear and tear could be affected by the orientation it was pointing.

It think is mostly an issue when the engine is not running. Fluids pool in the direction of gravity, which means you need to be able to drain the fluids in both directions - vertical and on its side - which places extra constraints on the engine design and requires you to add more valves.
« Last Edit: 10/16/2019 03:32 am by Lars-J »

Offline DOCinCT

Any chance the modified Tripod test stand is for the Vacuum Raptor  Elon recently tweeted about?

Offline Semmel

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Re: SpaceX renovating former Falcon 9 test stand at McGregor
« Reply #10 on: 10/16/2019 12:39 pm »
Any chance the modified Tripod test stand is for the Vacuum Raptor  Elon recently tweeted about?

Might make sense since the large nozzle would be subject to bending stresses that it would not experience in flight. This bending might influence the flow characteristics in the small channels of the active cooling.

Offline meberbs

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Re: SpaceX renovating former Falcon 9 test stand at McGregor
« Reply #11 on: 10/16/2019 05:45 pm »
Any chance the modified Tripod test stand is for the Vacuum Raptor  Elon recently tweeted about?

Might make sense since the large nozzle would be subject to bending stresses that it would not experience in flight. This bending might influence the flow characteristics in the small channels of the active cooling.
What is causing this bending stress that will not be seen during flight?
Gravity. But Musk has already tweeted that the vertical testing is to reduce wear and other issues in general, and this discussion should be public side in the thread for the recent article about the tripod stand.

Offline Semmel

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Re: SpaceX renovating former Falcon 9 test stand at McGregor
« Reply #12 on: 10/16/2019 07:43 pm »
I agree, this conversation could be held on the public side, but I want to answer the question with a reference. Ill report my own post after finishing writing it.

What is causing this bending stress that will not be seen during flight?
Gravity. But Musk has already tweeted that the vertical testing is to reduce wear and other issues in general, and this discussion should be public side in the thread for the recent article about the tripod stand.
I thought that Semmel was talking about bending forces while the engine is being run already in the vertical. That Elon message doesnt mention the nozzle in the manner Semmel is talking about.

Musk made a different explanation, but that was in the context of sea level raptor if I remember correctly.

The nozzle is large and necessarily thin to reduce mass. Lets look at the implications.

Forces during flight are acceleration, caused by the engines, in effect, the nozzle is pushed radially outwards by the exhaust pressure. Also the nozzle pushes on the rocket to induce acceleration, which is the whole point of the nozzle, which is directed along the long axis of the engine bell. The point is, the forces are more or less symmetrical and act on all parts of the nozzle equally.

In contrast, when mounted on a horizontal test stand, gravity would pull the nozzle downwards. This gives an unequal bending force on the nozzle, which is not present during flight. During flight, the rocket is practically in free fall (safe for its own acceleration), but there are no gravity induced bending forces.

Maybe this is not an issue, I dont know, I have no quantitative idea of the stresses involved.

Online edzieba

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Re: SpaceX renovating former Falcon 9 test stand at McGregor
« Reply #13 on: 10/17/2019 01:08 pm »
The forces from the exhaust gasses are orders of magnitude greater than the force of gravity acting on the bell structure.

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