Injector Technology Q&A

[sdsds]

I propose this thread as a place for discussion of both the history and current state of the art of combustion chamber propellant injection technology.

My immediate questions: {did TRW / does someone still} hold patents on pintle injection?

Do gas-on-gas combustion chambers benefit from pintle injection like liquid-on-liquid chambers?

What about gas-on-liquid (and do staged combustion engines do this)?

Or is it all just fluid-on-fluid, and gas vs. liquid is a non-issue?

[redneck]

I have been warned in the past that online discussion of injector technology can be construed as exporting controlled technologies. ITAR.  I don't know this for an absolute fact, but many pros wouldn't discuss on line things they were willing to describe in detail when in person.  I think the probability is that it is fairly safe to discuss here, unless you run afoul of the regulators sometime in the future and they want a lever. I have a few ideas that will remain half baked due to lack of access to experienced mentors.

[sdsds]

In that case it's solely a question about what's been openly published. I found:
http://www.rocket-propulsion.info/resources/articles/TRW_PINTLE_ENGINE.pdf
which looks like it's published by AIAA in July 2000.
https://arc.aiaa.org/doi/10.2514/6.2000-3871

And almost by definition the patents can't by restricted. Or can they?

[redneck]

I did a water demonstration of a couple of injector methods in Mojave 15 or so years ago and had some seriously interesting discussions. On line I blogged one later and got silence. If I ever get enough of the required solid rocket fuel* for testing, I would like to revisit both.

*Required solid fuel is paper rectangles with numbers and assorted other information that makes it useful for all debts public and private.

[markbike528cbx]

Patents:
Even if there was a patent by SpaceX for Falcon 1 (2004 timeframe), it would have expired by now >17 years.
https://patents.google.com/patent/US3699772

Patents can be classified, see early atomic energy patents.
https://www.uspto.gov/web/offices/pac/mpep/s150.html

A legal tussle between Northrup Grumman (TRW successor) and SpaceX was solved some time ago, as in 2005.
https://labusinessjournal.com/news/northrop-settles-rocket-dispute-with-spacex/

[sdsds]

A legal tussle between Northrup Grumman (TRW successor) and SpaceX was solved some time ago, as in 2005.
https://labusinessjournal.com/news/northrop-settles-rocket-dispute-with-spacex/

"Northrop then alleged in California state court that SpaceX and its chief engineer stole trade secrets for a rocket part."

I suppose an injector would be considered a rocket part. Grumman took over TRW in 2002; Merlin first flew in 2006. So 2005 might be reasonable for resolution of this.

https://www.wsj.com/articles/SB110805958574251469