×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

FH launch with crew 4 ?

FH launch with crew 4 ?

RE: FH launch with crew 4 ?

(OP)
seemed like smoke or soot ? particularly a little later as it separated from the rocket.

now the first stage is getting close to empty and shut down and over 200km high ... less optimum combustion ?

another day in paradise, or is paradise one day closer ?

RE: FH launch with crew 4 ?

Actually, the first stage was intentionally shut down and jettisoned for recovery, as shown later in their video, so it still has sufficient fuel to decelerate the first stage and power into a landing on the recovery ship.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: FH launch with crew 4 ?

(OP)
of course not "close to empty" ... such olde school thinking ! still close to the limits of it's operation, so maybe less complete combustion ?

another day in paradise, or is paradise one day closer ?

RE: FH launch with crew 4 ?

It's unclear, the plume separation occurs a full minute before MECO https://www.youtube.com/watch?v=n1KwjJhm9A0 and about 30 seconds after going supersonic, so perhaps some sort of Mach diamond?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: FH launch with crew 4 ?

My thought
Well mixed stoichiometric RP1 and oxygen will burn nearly blue but that is only the case inside the combustion chamber.
Fuel rich RP1 and oxygen burns with soot and color.

The orange flames are the burning of the excess fuel from the gas generator portion of the engine.
The gas generator exhaust is vented on the outer side of the nozzles on the 8 perimeter engines.
When the excess fuel hits the oxygen in the air and the main plume (reheating it) it burns producing the orange flame as shown in the 8 outer flares close to the rocket. But the gas generator on the center engine is not exposed to the air yet.
As the 9 plumes merge and mix farther down some air get mixed in and the excess fuel from the
center engine creating the main flare in the center but it is spread out due the extra mixing.

The flares are not as pronounced at lower elevations because the main plume has not spread out to provide the relighting of the gas generator plume, it just stays a trail of black soot and disperses.

Hydrae

RE: FH launch with crew 4 ?

Rockets typically throttle-down the engines before going super-sonic and then throttle back up afterwards. Add that to decreasing air density with altitude and much higher acceleration due to lower mass (fuel has been burned) and it's likely a number of aerodynamic effects are in play. Additionally engines running a sea level up to mid-altitudes have a shorter length rocket nozzle/bell, so the expansion behind the nozzle will be less optimal as it approaches higher altitude where pressures are less. The second and third stage rocket engine bell are longer to operate more efficiently at the lower air pressure or in the vacuum of space.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close