However, as a pair, BE4 or AR1 will offer around 30% more thrust than a single RD180. The pair will cost less than a single RD180 and with increased tank size, there will be fewer SRMs for the same mission.
Tory Bruno just said on reddit that two BE-4s will cost less than a single RD-180. Obviously that's a ballpark estimate and could very well change, but it's nice to know the target prices are competitive.https://www.reddit.com/r/ula/comments/47jsfy/new_be4_information_page_from_blue_origin/d0erahfQuoteHowever, as a pair, BE4 or AR1 will offer around 30% more thrust than a single RD180. The pair will cost less than a single RD180 and with increased tank size, there will be fewer SRMs for the same mission.
Quote from: ethan829 on 02/26/2016 04:33 pmTory Bruno just said on reddit that two BE-4s will cost less than a single RD-180. Obviously that's a ballpark estimate and could very well change, but it's nice to know the target prices are competitive.https://www.reddit.com/r/ula/comments/47jsfy/new_be4_information_page_from_blue_origin/d0erahfQuoteHowever, as a pair, BE4 or AR1 will offer around 30% more thrust than a single RD180. The pair will cost less than a single RD180 and with increased tank size, there will be fewer SRMs for the same mission.strange he has listed the AR1 in that comment. The final papers must not be signed and the AR1 is the backup?
Tory Bruno has mentioned on reddit that Blue Origin agreed to ULA's target cost for BE-4, although no mention of any specific number.https://www.reddit.com/r/ula/comments/43v33x/be4_forgings_assemble_full_engine_testing_later/czq86ebQuoteBE4 is our primary path because it started first, is fully funded, and Blue has signed up to our target cost. AR1 is our back up because engines are complicated, risky, and BE4 will be the largest methane engine ever built (so there's technical risk). I plan to downselect after BE4's full scale static testing in about a year. That's when we'll know if the technology will work and can be on schedule.
BE4 is our primary path because it started first, is fully funded, and Blue has signed up to our target cost. AR1 is our back up because engines are complicated, risky, and BE4 will be the largest methane engine ever built (so there's technical risk). I plan to downselect after BE4's full scale static testing in about a year. That's when we'll know if the technology will work and can be on schedule.
Where is the engine being built, and tested? I doubt it's the Kent, WA facility because of the noise, though Kent has equipment in the back of the main building that suspiciously suggests an engine test facility.--Damon
Bezos explained his philosophy on how to build a successful reusable engine: “Our strategy is we like to choose a medium-performing version of a high-performance architecture.” Here’s what that means: The Russian RD-180 engine is a high-performing version of a high performance architecture. It uses the best materials and pushes the performance envelope. It is the Ferrari of engines. But that comes with a cost. When it fires, the RD-180 engines produces extremely high chamber pressures of up to 3,700 psi. By comparison, the BE-4 engine produces a chamber pressure of 1,950 psi.
Ars Technica reports that the combustion chamber pressure of the BE-4 is 1950 psi.QuoteBezos explained his philosophy on how to build a successful reusable engine: “Our strategy is we like to choose a medium-performing version of a high-performance architecture.” Here’s what that means: The Russian RD-180 engine is a high-performing version of a high performance architecture. It uses the best materials and pushes the performance envelope. It is the Ferrari of engines. But that comes with a cost. When it fires, the RD-180 engines produces extremely high chamber pressures of up to 3,700 psi. By comparison, the BE-4 engine produces a chamber pressure of 1,950 psi.http://arstechnica.com/science/2016/03/behind-the-curtain-ars-goes-inside-blue-origins-secretive-rocket-factory/
CULBERSON COUNTY, Texas (Blue Origin PR) — BE-4 testing is well underway at Blue Origin. To date, we’ve completed more than 170 staged-combustion tests – including 51 starts on a single regeneratively cooled chamber and nozzle. The preburner performed flawlessly and the main injector consistently demonstrated performance at the high end of our predictions, giving us confidence that we’ll get good specific impulse when we go to full-scale engine testing later this year.
One of the many benefits of a privately funded engine development is that we can make and implement decisions quickly. Building these two new test cells is a $10 million commitment, and we as a team made the decision to move forward in 10 minutes.
Yes, and the RD-180 is still rated for 10 missions. No wonder it is not even close to the RD-180 in performance.
...so now that we have the chamber pressure information available, we could start speculating about other numbers. Plugging it into MPA, assuming an Isp-optimized O/F ratio and assuming that the nozzle is optimized for maximum thrust at sea level (more likely it'll be optimized for a somewhat lower pressure since Vulcan stages late) , I get a theoretical ideal specific impulse of 327 s SL and 351 s vac.MPA lite gives me a likely "as it turns out" specific impulse of 315 s SL and 339 s vac. This is where having the full version of the program would be nice to better approximate staged combustion efficiency and get an approximate T/W ratio. But either way, it seems to predict a somewhat lower specific impulse with the BE-4 than with the RD-180, and with a less dense fuel composition.
