SpaceX use pintles because head of propulsion Tom Mueller came from TRW. TRW was responsible for the LEMDE and did most of the early R&D work on the pintle injector, and still has proprietary data that hasn't been replicated. Masten Space uses pintles because Jon Goff got infected with the pintle meme somewhere along the way. I tend to use them on my projects as well. The only other group that does much with them is Gary Hudson's various projects like Air Launch. It's still definitely a niche injector even in the US. The primary advantage is simplicity and innate stability over a large throttle range, not necessarily C* efficiency. Though it's not bad either. They also have higher bandwidth (thrust wrt time) than most other injectors. Back to the nozzle thing, it sounds like Mr. Glass might have been misled, and the Soviet Union just used simple nozzles. It had been my impression that their high performance engines were more attributed to high performance cycles than unusual nozzle performance. Ben On Tue, Nov 12, 2013 at 4:29 PM, Alexander Mikhailov <avmich@xxxxxxxxx> wrote: > As I understand, single component injectors are more popular in USA, and > comparatively double component injectors - in Russian engines. > > SpaceX's Merlin uses pintles. > > A very interesting case is F-1 where the main task was to avoid > oscillations, not improve combustion, and the injector pattern was > essential... > > > On Tuesday, November 12, 2013 3:24 PM, George Herbert > <george.herbert@xxxxxxxxx> wrote: > > > > On Tue, Nov 12, 2013 at 2:51 PM, Alexander Mikhailov <avmich@xxxxxxxxx> > wrote: > > .... > And one more thing - it's strange to hear that US, with the tradition > of using pintle injectors, have more optimal combustion process, while > Russian injectors commonly have many much smaller injectors, matched > by flow. Pintle should have other advantages, I guess... > > > The US pintle engines were mostly involved with the Lunar Module descent > engine (LMDE) and its derivatives (which ended up in the TR201 which was > classic Delta's second stage engine), > > Nearly all flown US engines are classic injectors. > > > -- > -george william herbert > george.herbert@xxxxxxxxx > >