Author Topic: ARCA  (Read 87884 times)

Offline Nomadd

  • Senior Member
  • *****
  • Posts: 8425
  • Highway Whatever
  • Liked: 57090
  • Likes Given: 1102
Re: ARCA
« Reply #280 on: 02/21/2022 11:35 pm »

I can't find the source, but someone had an image from a paper on an air augmented rocket nozzles that had holes similar to that. The bigger issue is that their duct is probably too short.
There's way bigger issues than that.
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline Gliderflyer

Re: ARCA
« Reply #281 on: 02/21/2022 11:55 pm »
Oh yeah, from an orbital launch vehicle system perspective it's a complete disaster. But focusing just on the "will this duct increase my 45 second steam rocket Isp" aspect, it probably needs to be longer.
I tried it at home

Offline LouScheffer

  • Senior Member
  • *****
  • Posts: 2948
  • Liked: 5172
  • Likes Given: 657
Re: ARCA
« Reply #282 on: 02/22/2022 01:49 am »
I can't find the source, but someone had an image from a paper on an air augmented rocket nozzles that had holes similar to that. The bigger issue is that their duct is probably too short.
Here's a diagram from a thesis on air-augmented rockets.  While certainly not to scale, it surely proposes a much longer duct than the EcoRocket.  Also, air-augmentation works better on conventional fuel-rich rocket engines, where the unburnt fuel can combust in the duct with the incoming air, further increasing the thrust.  But with water as your propellant this increase will not be present.

Offline Steven Pietrobon

  • Member
  • Senior Member
  • *****
  • Posts: 31477
  • Adelaide, Australia
    • Steven Pietrobon's Space Archive
  • Liked: 19702
  • Likes Given: 3251
Re: ARCA
« Reply #283 on: 05/01/2022 05:30 am »
ARCA has posted a series of videos of their involvement in the Ansari X-Prize. The last few videos were taken in the US at various X-Prize presentations which I thought were quite interesting. Here's the first video. You can find the rest on the ARCA YouTube channel.



Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Asteroza

  • Senior Member
  • *****
  • Posts: 2146
  • Liked: 752
  • Likes Given: 26
Re: ARCA
« Reply #284 on: 05/09/2022 06:42 am »
I can't find the source, but someone had an image from a paper on an air augmented rocket nozzles that had holes similar to that. The bigger issue is that their duct is probably too short.
Here's a diagram from a thesis on air-augmented rockets.  While certainly not to scale, it surely proposes a much longer duct than the EcoRocket.  Also, air-augmentation works better on conventional fuel-rich rocket engines, where the unburnt fuel can combust in the duct with the incoming air, further increasing the thrust.  But with water as your propellant this increase will not be present.

While highly unlikely to be the case with ARCA, there might be a case that rapid cooling of the exhaust due to expansion in the primary nozzle might facilitate condensation in the area of the duct, creating a suction motion? I vaguely remember israeli work on underwater ejector ramjets that used a steam ejector with rapid condensation to change pressure, sucking in water from the front.

https://frpc.net.technion.ac.il/marine-two-phase-jet-propulsion-and-bubbly-flows/

Offline CameronD

  • Senior Member
  • *****
  • Posts: 2208
  • Melbourne, Australia
    • Norton Consultants
  • Liked: 784
  • Likes Given: 491
Re: ARCA
« Reply #285 on: 07/11/2022 02:07 am »
In case anyone was wondering:  "The launch was scheduled for April 22, but got stopped by the Air Traffic Management. We are currently making efforts to relocate the launch operations away from the Black Sea area."

They have posted a few new videos on their YT channel about their latest thought bubble :  AMi Exploration
https://www.youtube.com/user/ARCAchannel
Quote
AMi Exploration is an ARCA Space technological and crypto initiative of unprecedented magnitude, aiming at space exploration development driven by economic rationale and sustainability.

The program will be unveiled in the next weeks
https://www.amiexploration.com/

It appears they had planned a PR campaign at their "Cosmobase" on July 7th, but it was a wash-out due to heavy rain!!
 
« Last Edit: 07/11/2022 02:13 am by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline daedalus1

  • Full Member
  • ****
  • Posts: 646
  • uk
  • Liked: 331
  • Likes Given: 0
Re: ARCA
« Reply #286 on: 07/11/2022 06:28 am »
The only thing I was wondering is how much longer this scam is going to go on.

Offline CameronD

  • Senior Member
  • *****
  • Posts: 2208
  • Melbourne, Australia
    • Norton Consultants
  • Liked: 784
  • Likes Given: 491
Re: ARCA
« Reply #287 on: 07/11/2022 11:10 pm »
The only thing I was wondering is how much longer this scam is going to go on.

Well, the guy has to earn a living somehow.. you can't begrudge him that.

Besides, this particular scam is no worse than many of the others in this topic - and at least he has hardware (and a YT channel) to show for it.
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Online TrevorMonty

Re: ARCA
« Reply #288 on: 07/12/2022 03:06 am »
The only thing I was wondering is how much longer this scam is going to go on.

Well, the guy has to earn a living somehow.. you can't begrudge him that.

Besides, this particular scam is no worse than many of the others in this topic - and at least he has hardware (and a YT channel) to show for it.
HW that breathes fire or steam is big step up from PowerPoint rockets.
« Last Edit: 07/21/2022 01:47 am by zubenelgenubi »

Offline trimeta

  • Full Member
  • ****
  • Posts: 1093
  • Kansas City, MO
  • Liked: 1538
  • Likes Given: 48
Re: ARCA
« Reply #289 on: 07/20/2022 05:27 pm »

Offline Toast

Re: ARCA
« Reply #290 on: 07/20/2022 06:21 pm »
You know what ARCA really needed to finally achieve success? More OTRAG!
White paper where they elaborate on this "plan."

Even by ARCA standards this is jumping the shark. I legitimately thought this was satire, but it's real.

EDIT: Oh, good, they're also launching a cryptocurrency token to fund it, just in case anybody hadn't completed their grifter bingo card yet.
« Last Edit: 07/20/2022 06:25 pm by Toast »

Online niwax

  • Full Member
  • ****
  • Posts: 1320
  • Germany
    • SpaceX Booster List
  • Liked: 1857
  • Likes Given: 158
Re: ARCA
« Reply #291 on: 07/20/2022 06:30 pm »
What about this was supposed to be Eco exactly? Assuming a 90% mass fraction, they're throwing away more aluminium per launch than other rockets use propellant.
Which booster has the most soot? SpaceX booster launch history! (discussion)

Offline trimeta

  • Full Member
  • ****
  • Posts: 1093
  • Kansas City, MO
  • Liked: 1538
  • Likes Given: 48
Re: ARCA
« Reply #292 on: 07/20/2022 06:41 pm »
What about this was supposed to be Eco exactly? Assuming a 90% mass fraction, they're throwing away more aluminium per launch than other rockets use propellant.

That's the best part, all of the cores used in the first two stages are reusable! Truly, their 96% reusable vehicle will be revolutionary! Insofar as its success would overthrow multiple laws of physics.

Offline Star One

  • Senior Member
  • *****
  • Posts: 13247
  • UK
  • Liked: 3622
  • Likes Given: 220
Re: ARCA
« Reply #293 on: 07/20/2022 06:46 pm »
You know what ARCA really needed to finally achieve success? More OTRAG!
White paper where they elaborate on this "plan."

Even by ARCA standards this is jumping the shark. I legitimately thought this was satire, but it's real.

EDIT: Oh, good, they're also launching a cryptocurrency token to fund it, just in case anybody hadn't completed their grifter bingo card yet.
Nope they havenít launched NFTs yet.

Offline libra

  • Full Member
  • ****
  • Posts: 1774
  • Liked: 1154
  • Likes Given: 2281
Re: ARCA
« Reply #294 on: 07/20/2022 06:49 pm »
They should hire Saul Goodman as lawyer, really. Also for the promotional stuff.

Offline Lars-J

  • Senior Member
  • *****
  • Posts: 6711
  • California
  • Liked: 8138
  • Likes Given: 5181
Re: ARCA
« Reply #295 on: 07/20/2022 06:55 pm »
This takes dumb and dumber to the next level... dumberest.  ;D
« Last Edit: 07/20/2022 06:56 pm by Lars-J »

Offline jstrotha0975

  • Full Member
  • ****
  • Posts: 416
  • United States
  • Liked: 256
  • Likes Given: 1960
Re: ARCA
« Reply #296 on: 07/20/2022 07:41 pm »
Somewhat OTRAG like.

Offline Lars-J

  • Senior Member
  • *****
  • Posts: 6711
  • California
  • Liked: 8138
  • Likes Given: 5181
Re: ARCA
« Reply #297 on: 07/20/2022 07:52 pm »
Yes, like Otrag, but dumber. The LV is wider than it is tall. I don't think they understand the issues that would cause.

But it is all a scam, so I guess it doesn't matter?
« Last Edit: 07/20/2022 07:52 pm by Lars-J »

Offline whitelancer64

Re: ARCA
« Reply #298 on: 07/20/2022 07:52 pm »
ARCA took https://what-if.xkcd.com/24/ as a challenge.

"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Online TrevorMonty

Re: ARCA
« Reply #299 on: 07/20/2022 09:42 pm »
Yes, like Otrag, but dumber. The LV is wider than it is tall. I don't think they understand the issues that would cause.

But it is all a scam, so I guess it doesn't matter?
They are now going after Crypto Currency investors.
« Last Edit: 07/21/2022 12:57 am by zubenelgenubi »

Tags:
 

Advertisement NovaTech
Advertisement SkyTale Software GmbH
Advertisement Northrop Grumman
Advertisement
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1