Author Topic: Spinlaunch... Can it succeed?  (Read 83049 times)

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Online EEVblog

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Re: Spinlaunch... Can it succeed?
« Reply #350 on: August 09, 2022, 09:49:38 am »
Can others see my comment?

scrolled deep into the comments, but not a single one from you.

The Parker solar probe video?
I just checked on anotherb rowswr and it's there, along with someone who replied to me. So I'm definitely not blocked on his channel.

yes on that one, seems there is an algorithm also on comments which decides which ones are shown to whom.

That is bizzare. I've never seen or heard of that.
 

Offline Rick Law

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Re: Spinlaunch... Can it succeed?
« Reply #351 on: August 09, 2022, 04:14:53 pm »
Stupid question....  Why isn't Spinlaunch located at a higher elevation than where they are to reduce air resistance and require less energy and cost? Why not Alma, Colorado which is at 10,000 feet?
When you consider location, you need to take into account many factors. Like workforce availability, logistics, land use planning and so on. It may be the best place in one regard but a complete showstopper in others. In US AFAIK all of the serious launch sites are located on the coastline, so rockets fly over the water and not populated areas.

10,000 feet doesn't make enough of a difference.  60 miles is where one can reasonably consider low earth orbit as lowest and that is over 300,000 feet.  10,000 feet will help but not significantly.

Spinlaunch's problem is not just with the launch machine.  They can engineer all the launch machine problems away -- at great cost but it is doable.  The main issue really is the payload must withstand 11,000g at their planned mach 3 launch.  That is a lot of force for the payload to deal with and (re)engineering the payload to survive that will be a very expensive thing to do.  One can imagine the work in recreating a PCB so that every component on the PCB will survive being pulled by a force 11000x its own weight.

Furthermore, mach 3 is not enough.  The escape velocity is around mach 33, so mach 3 launch will need rocket booster to take it all the way up.  You don't need escape velocity to orbit since orbiting means you are not escaping by definition.  We can't estimate the velocity they actually need since we do not know the aerodynamics of the launch vehicle.  We do know that whatever shape it is, some air resistance will be there.    Both Air-drag and Centripetal force are proportional to V2 .  2x velocity means 4x the force.  10x the velocity means 100x the force.  Mach 33 is 11x mach 3, so it will be 112x11000 = 1,331,000g centripetal force and that is before adding extra velocity to deal with the air drag!

The $ saving is the difference of "traditional" vs "spin" launch cost.  I just can't see it as practical (financially and otherwise) to strengthen most kinds of payloads with the budget for strengthening limited to max $ delta of "traditional" vs "spin" launching.  Even with raw material (such as water, or liquid rocket fuel) will require a strengthen container and 1.3 million g needs a lot of strengthening to handle.

Spinlaunch being technologically feasible maybe is a yes, but Spinlaunch being economically viable is a no in my book.
 

Offline rob77

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Re: Spinlaunch... Can it succeed?
« Reply #352 on: August 09, 2022, 04:35:58 pm »
Stupid question....  Why isn't Spinlaunch located at a higher elevation than where they are to reduce air resistance and require less energy and cost? Why not Alma, Colorado which is at 10,000 feet?
When you consider location, you need to take into account many factors. Like workforce availability, logistics, land use planning and so on. It may be the best place in one regard but a complete showstopper in others. In US AFAIK all of the serious launch sites are located on the coastline, so rockets fly over the water and not populated areas.

10,000 feet doesn't make enough of a difference.  60 miles is where one can reasonably consider low earth orbit as lowest and that is over 300,000 feet.  10,000 feet will help but not significantly.

Spinlaunch's problem is not just with the launch machine.  They can engineer all the launch machine problems away -- at great cost but it is doable.  The main issue really is the payload must withstand 11,000g at their planned mach 3 launch.  That is a lot of force for the payload to deal with and (re)engineering the payload to survive that will be a very expensive thing to do.  One can imagine the work in recreating a PCB so that every component on the PCB will survive being pulled by a force 11000x its own weight.

Furthermore, mach 3 is not enough.  The escape velocity is around mach 33, so mach 3 launch will need rocket booster to take it all the way up.  You don't need escape velocity to orbit since orbiting means you are not escaping by definition.  We can't estimate the velocity they actually need since we do not know the aerodynamics of the launch vehicle.  We do know that whatever shape it is, some air resistance will be there.    Both Air-drag and Centripetal force are proportional to V2 .  2x velocity means 4x the force.  10x the velocity means 100x the force.  Mach 33 is 11x mach 3, so it will be 112x11000 = 1,331,000g centripetal force and that is before adding extra velocity to deal with the air drag!

The $ saving is the difference of "traditional" vs "spin" launch cost.  I just can't see it as practical (financially and otherwise) to strengthen most kinds of payloads with the budget for strengthening limited to max $ delta of "traditional" vs "spin" launching.  Even with raw material (such as water, or liquid rocket fuel) will require a strengthen container and 1.3 million g needs a lot of strengthening to handle.

Spinlaunch being technologically feasible maybe is a yes, but Spinlaunch being economically viable is a no in my book.


they're planning Mach 6 release, they're not planning to go orbital with the spinlaunch itself.. basically the spinlaunch will replace only the 1st stage of a conventional rocket. but the practicality of the solution is questionable.. there is no free l(a)unch, you still need to burn the fuel either in a rocket engine or in a turbine creating electricity for the spiner.
another point is the ability to recover from an anomaly... with conventional rocket you loose one rocket and the payload... if the spinner suffers an anomaly, you loose the payload and pretty much need to rebuild the whole spinlaunch facility from scratch.
 

Offline DougSpindler

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Re: Spinlaunch... Can it succeed?
« Reply #353 on: August 09, 2022, 05:16:41 pm »
Why do they think they can get this to work the US Navy spent $500M for a linear electrotechnical launch system that failed.  They were try to get the same speeds.  If the Navy could get it it work, why does Spinlaunch tjey can get it to work?
 

Offline PlainName

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Re: Spinlaunch... Can it succeed?
« Reply #354 on: August 09, 2022, 06:14:44 pm »
Why do they think they can get this to work the US Navy spent $500M for a linear electrotechnical launch system that failed.  They were try to get the same speeds.  If the Navy could get it it work, why does Spinlaunch tjey can get it to work?

If you read the article you linked to you will see that the US Navy were wanting a gun, not a space launcher. They figured it not appropriate because of the range (110 miles, which put the gun within range of enemy fire) and rate of fire. Also, hypersonics looked a better bet.

That the US Navy looked at something that was only peripherally similar to the spinlauncher, and deemed it not right for a different purpose to spinlauncher, just reinforces that you shouldn't be comparing it to spinlauncher.
 

Offline Rick Law

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Re: Spinlaunch... Can it succeed?
« Reply #355 on: August 09, 2022, 06:15:57 pm »
...
they're planning Mach 6 release, they're not planning to go orbital with the spinlaunch itself.. basically the spinlaunch will replace only the 1st stage of a conventional rocket. but the practicality of the solution is questionable.. there is no free l(a)unch, you still need to burn the fuel either in a rocket engine or in a turbine creating electricity for the spiner.
another point is the ability to recover from an anomaly... with conventional rocket you loose one rocket and the payload... if the spinner suffers an anomaly, you loose the payload and pretty much need to rebuild the whole spinlaunch facility from scratch.
When this thread started, they were planning mach 3.  At mach 6, the problem quadrupled.  44,000g! 

Presumably, the rocket to do the final phase will be aiming vertically up at launch.  That means the centripetal force will be towards the side skin of the rocket and not the base.  For the side skin to hold 44,000 times the weight of the fuel, that should be rather interesting.  Just to add more excitement, some solid fuel could ignite by the pressure alone...

Why do they think they can get this to work the US Navy spent $500M for a linear electrotechnical launch system that failed.  They were try to get the same speeds.  If the Navy could get it it work, why does Spinlaunch tjey can get it to work?

They don't need this to work.  They just need to convince enough investors that it could work.

The Navy (linear rail gun) actually has more advantage beside the $500m.  They are dealing acceleration g (pointing at the base of the rocket).  Whereas, the spinner's centriptal g is lateral (pointing to the side-skin of the payload).  The other advantage is size.  Recall reply #39 I wrote earlier, For the same exit velocity and size (rail gun rail length = spinner diameter), the rail gun's acceleration g force is merely 1/4 of the spinner's centripetal g force.

Here's is reply 39 with the math:
What would the centripetal g force on the payload be compared with simply shooting it out of a very large gun pointed skyward?

In comparing one force verses another acting on the same mass, since f=ma are true for both cases (Newton's second law of motion), mass cancels out leaving you just comparing acceleration.

For the object orbiting around a center, V is the linear velocity while orbiting, and it equals the velocity at release:
Centripetal /centrifugal acceleration is a = V2/R, here R is the distance to the center of rotation.

For the object being shot out of a barrel (or rail of a rail-gun), V is the exit velocity of the object when leaving the barrel
Shooting out of a gun is difficult to say since acceleration by gas-explosion is not constant while in the barrel.  Let's assume it is constant acceleration like you can do with a linear motor catapult or rail-gun.  With such assumption, while in the barrel, then:
Linear constant acceleration would be  a = V2/2L, here L is the length of the gun barrel.

So, if your gun is half the radius of the centrifuge, your acceleration is the same and thus the force are the same.  Of course, radius is just 1/2 the width (diameter) of the centrifuge.

I don't know about these SpinLaunch folks...  I think building a rail-gun 25 meters in length would be easier than building a centrifuge 100 meters in diameter, and a linear rail is far easier to aim.
 

Offline Neilm

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Re: Spinlaunch... Can it succeed?
« Reply #356 on: August 09, 2022, 06:37:49 pm »
I could see this working on bodies with lower mass so you could throw (for instance) the output of mines into orbit where something could rendezvous with it. I can't see it being practical on Earth
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Online SiliconWizard

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Re: Spinlaunch... Can it succeed?
« Reply #357 on: August 09, 2022, 09:29:35 pm »
It does look like great weapon technology though. The 21st century catapult!
 

Offline DougSpindler

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Re: Spinlaunch... Can it succeed?
« Reply #358 on: August 09, 2022, 09:54:30 pm »
Or a lever arm that's long enough.
 

Online EEVblog

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Re: Spinlaunch... Can it succeed?
« Reply #359 on: August 10, 2022, 12:27:15 am »
Spinlaunch's problem is not just with the launch machine.  They can engineer all the launch machine problems away -- at great cost but it is doable.  The main issue really is the payload must withstand 11,000g at their planned mach 3 launch.  That is a lot of force for the payload to deal with and (re)engineering the payload to survive that will be a very expensive thing to do.  One can imagine the work in recreating a PCB so that every component on the PCB will survive being pulled by a force 11000x its own weight.

Furthermore, mach 3 is not enough.  The escape velocity is around mach 33, so mach 3 launch will need rocket booster to take it all the way up.  You don't need escape velocity to orbit since orbiting means you are not escaping by definition.  We can't estimate the velocity they actually need since we do not know the aerodynamics of the launch vehicle.  We do know that whatever shape it is, some air resistance will be there.    Both Air-drag and Centripetal force are proportional to V2 .  2x velocity means 4x the force.  10x the velocity means 100x the force.  Mach 33 is 11x mach 3, so it will be 112x11000 = 1,331,000g centripetal force and that is before adding extra velocity to deal with the air drag!

I'm no rocket or mechnical guy, but a rocket for the upper stage surviving these sorts of forces must not be easy. Electronics would be the least of your worries I think.
 

Offline Marco

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Re: Spinlaunch... Can it succeed?
« Reply #360 on: August 10, 2022, 02:23:34 am »
Greenlaunch (the less ambitious company started after Quicklaunch didn't get any traction) thinks they need 6 kms with a hydrogen gas gun, with a 100 second rocket burn to get into an orbit. So Mach 18, Mach 3 or 6 seems a little tame.
 

Offline mc172

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Re: Spinlaunch... Can it succeed?
« Reply #361 on: August 10, 2022, 06:16:38 am »
Can others see my comment?

scrolled deep into the comments, but not a single one from you.

I scrolled for a while and couldn't see a single critical or negative comment.
 

Online EEVblog

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Re: Spinlaunch... Can it succeed?
« Reply #362 on: August 10, 2022, 06:31:37 am »
I scrolled for a while and couldn't see a single critical or negative comment.

I'd be very dissapointed if he's deleting comments. That would be very bad for his brand.
 

Offline PlainName

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Re: Spinlaunch... Can it succeed?
« Reply #363 on: August 10, 2022, 11:55:31 am »
I scrolled for a while and couldn't see a single critical or negative comment.

I'd be very dissapointed if he's deleting comments. That would be very bad for his brand.

That would need people to notice, and then be able to kick up a fuss somewhere (else) about it. And the fans to notice that. The odd video being censored would be just a weird anomaly.

 

Offline madires

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Re: Spinlaunch... Can it succeed?
« Reply #364 on: August 10, 2022, 02:04:15 pm »
I scrolled for a while and couldn't see a single critical or negative comment.

I saw two mildly critical comments. One was about a possible error in a graph and the other one about potential scaling issues. Such a video would attract usually also a lot of negative comments besides the cheers. So I think it's safe to assume that negative comments are deleted. A YT channel promoting engineering while suppressing critcial thinking, one of the important skills of any engineering, is detrimental to engineering. It seems it's just another click-bait channel.
 

Offline PlainName

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Re: Spinlaunch... Can it succeed?
« Reply #365 on: August 10, 2022, 02:58:31 pm »
Quote
A YT channel promoting engineering while suppressing critcial thinking

To be fair, a lot of negative comments are just keyboard warriors blowing off. No thinking required at all, never mind critical.
 

Offline madires

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Re: Spinlaunch... Can it succeed?
« Reply #366 on: August 10, 2022, 04:23:34 pm »
Sure! I didn't mean nonsense, trolling and SPAM comments.
 

Offline Bud

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Re: Spinlaunch... Can it succeed?
« Reply #367 on: August 10, 2022, 04:27:24 pm »
It does look like great weapon technology though. The 21st century catapult!
Not a military expert in any way but common sense tells today's weapons must be mobile. You can't move this thing any reasonably fast. It would be a sitting duck.
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Online EEVblog

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Re: Spinlaunch... Can it succeed?
« Reply #368 on: August 14, 2022, 10:42:10 am »
I scrolled for a while and couldn't see a single critical or negative comment.

I'd be very dissapointed if he's deleting comments. That would be very bad for his brand.

That would need people to notice, and then be able to kick up a fuss somewhere (else) about it. And the fans to notice that. The odd video being censored would be just a weird anomaly.

Yes, I suspect you are right, most people don't notice nor care.
 

Offline wraper

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Re: Spinlaunch... Can it succeed?
« Reply #369 on: August 14, 2022, 11:48:34 am »
another point is the ability to recover from an anomaly... with conventional rocket you loose one rocket and the payload... if the spinner suffers an anomaly, you loose the payload and pretty much need to rebuild the whole spinlaunch facility from scratch.
With conventional rockets you can lose facility as well. In the past rockets exploded on a launch pad or crashed on top of it.





« Last Edit: August 14, 2022, 11:57:50 am by wraper »
 

Offline wraper

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Re: Spinlaunch... Can it succeed?
« Reply #370 on: August 14, 2022, 12:04:30 pm »
It does look like great weapon technology though. The 21st century catapult!
Not a military expert in any way but common sense tells today's weapons must be mobile. You can't move this thing any reasonably fast. It would be a sitting duck.
Not the main problem. IIRC they need to spin it for hours before rocket can be launched.
 

Offline DougSpindler

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Re: Spinlaunch... Can it succeed?
« Reply #371 on: August 15, 2022, 05:10:46 pm »
Germans seemed to have figured out the rocket think rather quickly.  And this was while they were at war, being bombed heavily and not doing so well in the war.  And there's a was mobile. Took them less than an hour to get one launched.   And yes they had failures in the beginning, but that didn't stop them or successfully launched over 3,000 with most of them getting close to their targets.


 

Offline Rick Law

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Re: Spinlaunch... Can it succeed?
« Reply #372 on: August 15, 2022, 09:47:44 pm »
It was somewhat unfair to think of the "Space Race" as USA Scientist vs the USSR Scientist.  It would have been more accurate to think of it as "Our Germans" vs "Their Germans".  Without the German Scientists and experience, we (both USA and USSR) would still get into Space but later.

Now had the NAZI Germans follow down the spin launch path, they likely would have lost the war sooner (no need for the allies to expand resources to deal with V2).  Throwing ONE bomb every two days per wheel would have been nothing significant.  The Germans would literally be spinning their wheels and going no where.  Spin launching for the NAZI likely would have saved life, thousands.

Spinlaunch should add that to their marketing:  Spinlaunch could have ended the war sooner if only the NAZI thought of it...
 

Offline DougSpindler

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Re: Spinlaunch... Can it succeed?
« Reply #373 on: August 15, 2022, 10:59:51 pm »
It was somewhat unfair to think of the "Space Race" as USA Scientist vs the USSR Scientist.  It would have been more accurate to think of it as "Our Germans" vs "Their Germans".  Without the German Scientists and experience, we (both USA and USSR) would still get into Space but later.

Now had the NAZI Germans follow down the spin launch path, they likely would have lost the war sooner (no need for the allies to expand resources to deal with V2).  Throwing ONE bomb every two days per wheel would have been nothing significant.  The Germans would literally be spinning their wheels and going no where.  Spin launching for the NAZI likely would have saved life, thousands.

Spinlaunch should add that to their marketing:  Spinlaunch could have ended the war sooner if only the NAZI thought of it...


Spinlaunch just seems way over complicated compared to something like the German V3 or Schwerer Gustav.  Amazing what the Germans were able to do build while at war and being bombed.  Yet when the Germans were winning the war a group of 400 poorly trained 18 - 26 year old women who held off the entire advancing German army leading to their defeat.


 

Offline Rick Law

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Re: Spinlaunch... Can it succeed?
« Reply #374 on: August 16, 2022, 01:41:32 am »
...
Spinlaunch just seems way over complicated compared to something like the German V3 or Schwerer Gustav.  Amazing what the Germans were able to do build while at war and being bombed.  Yet when the Germans were winning the war a group of 400 poorly trained 18 - 26 year old women who held off the entire advancing German army leading to their defeat.
...

This is not electronics, but I hate to have someone look at this forum and thinks we know nothing outside soldering and DMMs.

A German army "kempf group" was merely an informal battle group to achieve a task.  The small action against the forward element of the 6th army was certainly successful, but it is a great exaggeration to consider it THE REASON for the failure of the 6th Army or as reason for the defeat of Germany's eastern effort.

Mark Felton is a good historian and I rather like his video as well, but I think he too would consider taking that battle as the main cause of the Stalingrad outcome a great exaggeration.

Stalingrad was held by Soviet Army groups against an already drawn down German 6th Army that reached Stalingrad.  Had Germany been able to adequately resupply the 6th Army prior to the start of Stalingrad or during the Stalingrad battles, the outcome would likely have been different.  Even then, it took Operation Uranus (1.14 million Soviet soldiers) that finally encircled the 400,000 axis German troops, and both the north and south pincer movements were attacking mostly non-German axis troops.

Stalingrad itself did not lead to the defeat of Germany in the East.  It was logistics for the Germans, and the need for the troops elsewhere that stopped the Germans.  Even after Stalingrad, they were not yet defeated.  During the Battle of Kursk (Operation Citadel), they managed successfully inching toward the goal until they had to pull resources out from the battle to reinforce Italy when the Allies landed there.

Don't kid yourself, it took a lot more than a few hundred woman to stop the Germans in the East.  It took millions and millions of Soviet troop to accomplish that task.
 


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