I'm really looking forward to seeing this engine tested at full scale. It would be a very big and important milestone for Blue, and it could potentially shift a lot of things in the industry.A 2,500 kN American ORSC engine! And with a new fuel type to boot! Who would have thought that we would get something like this that fast?
However, BE4 remains our primary path and is doing very well, moving from near full scale into full scale testing as I type this. They have also been able to commit to a recurring price that meets our competitiveness needs.
Full scale firings is the big milestone. That likely happens early in 2017.
For BE-4, not only do we have to design the engine itself, we also have to develop custom tools to make it. One of these tools is an automated electrical discharge machining (EDM) drilling machine. The EDM precisely locates and burns more than 4,000 tightly dimensioned holes into the nozzle and main combustion chamber, providing entry to the regenerative cooling channels. As far as we know, this particular EDM machine is the only one of its kind in the world. It has 11 axes of motion allowing for precise hole location and accuracy within a few thousands of an inch. Its dual-head design results in reduced cycle time for the drilled holes. Brass multichannel electrodes are used to drill the holes. Water can be pumped through the electrode in order to speed up the drilling cycle. The use of water also helps flush the hole and remove the powder-like foreign object debris generated by the process. This eliminates the concern for plugging cooling channels, which can easily occur with conventional drilling methods. A pair of automated electrode-changing stations allows the EDM to continuously operate for long cycle times at an average rate of one hole every 90 seconds. Building and operating custom tools of this magnitude is a big investment, but it’s critical for developing an engine that will power America’s access to space in the future. A pretty wise investment, if you ask me. Gradatim Ferociter! Jeff Bezos PS: Blue Origin is hiring. Check out our Careers page and apply.
So -- 4000 holes * 90 seconds = 100 hours on this machine to drill the holes for one engine? I suppose that doesn't matter too much if your intention is to reuse things so you don't have to build that many.
Quote from: acsawdey on 11/18/2016 02:49 pmSo -- 4000 holes * 90 seconds = 100 hours on this machine to drill the holes for one engine? I suppose that doesn't matter too much if your intention is to reuse things so you don't have to build that many.RS-68 has a lead time of 36 months. I think that the ablative MCC/nozzle takes something like 6 months to do. 100hr for an injector plate is really fast.
Quote from: baldusi on 11/18/2016 05:38 pmQuote from: acsawdey on 11/18/2016 02:49 pmSo -- 4000 holes * 90 seconds = 100 hours on this machine to drill the holes for one engine? I suppose that doesn't matter too much if your intention is to reuse things so you don't have to build that many.RS-68 has a lead time of 36 months. I think that the ablative MCC/nozzle takes something like 6 months to do. 100hr for an injector plate is really fast.RS-68A is slightly less than 36 months now due to improvements and lessons learned being applied to its manufacturing process.Theoretically you could install more EDM arms to speed the process up, but the current setup is fine for testing and initial production rate.
Where's the complexity on the RS-68A thought that was designed to be cheap?
Quote from: Prober on 11/22/2016 03:59 pmWhere's the complexity on the RS-68A thought that was designed to be cheap?Compared to SSME it was derived from, any rocket engine short of the F1 is designed to be cheaper ...
Quote from: Space Ghost 1962 on 11/22/2016 06:07 pmQuote from: Prober on 11/22/2016 03:59 pmWhere's the complexity on the RS-68A thought that was designed to be cheap?Compared to SSME it was derived from, any rocket engine short of the F1 is designed to be cheaper ... I think that they used an ablative main combustion chamber and nozzle to "cut costs", and made a very simple gas generator.
They also re-used as much of the SSME tooling as possible. Supposedly they would build 30 or more engines per year and thus it would be "dirty cheap".
Then the project had lower performance than expected, DIV was found to have cheated and thus its orders slashed and SSME production was ended. Perfect storm that made it very expensive.
If you look at Merlin's history, you will see that at the time (late 90s early 2000s) it was thought that ablative MCC and nozzle were a great cost trade off. Apparently the reality has been different. Ditto with hydrogen/LOX.
I think that too many decades of Rocketdyne/NASA making all decisions made them think that their way of doing things was the only way. Then came NPO Energomash to the international market and you know how it ended.
The BE4 production rate should be >30 a year. 10-20 for ULA (5-10 x Vulcan). 1 per NG flight for expendable US. 7 x NG Booster, even though it is reusable they will need to build a small fleet of boosters plus replace engines after so many flights. By time Vulcan is reusing BE4 in 2023-25, NG should have high flight rate assuming Blues vision for HSF pans out.
Why "commercial" worked better for Merlin than RS68 was the thumb on the scales.Watching BE4 closely for thumbs on the scales like AR1 already has. Raptor has no thumb on the scale.
BE-4 has some important advantages in cost wrt the RS-68A.
One is that since SLI in the 1990s, the US has gone through a lot of engine development efforts through many companies. While some don't even exist anymore, many of the Blue engineers have worked previously on many engine projects and they have a huge stack of lessons learned.The other is that a lot of companies have proven that engines can be done relatively cheap. Blue can just leverage the best practices and then innovate on cost.
But more importantly, is that Blue has a very knowledgeable leader that let's engineers make the best technical choice since he is not married to any supplier.
It is not surprising that KBKhA, NPO Energomash, SpaceX and Blue Origin went with CH4/LOX when they had to do a highly reusable engine. Rocketdyne/Aerojet have always proposed hydrolox, because that was NASA's heritage.
The last is the financing source. They have an extremely predictable cashflow and only care about long term cost. No worries about keeping the program, maintaining the appropriations or keeping big contracts.
Can you please talk a little about what you mean by "thumb on the scale"?
Robert Goddard’s first rockets used compressed gas to force the liquid propellants into the engine thrust chambers. While simple in design and a logical starting point, he quickly realized the limitations with this approach: it requires thick-walled heavy propellant tanks and limits the engine’s chamber pressure and performance, both of which limit payload capacity. The answer was turbopumps. Store the propellants in low-pressure light tanks, and then pump the propellants up to high pressure just ahead of injection into the main chamber.For even more performance, you can add one or more boost pumps ahead of the main pumps. We’ve done that on the oxidizer side of our BE-4 engine. Our Ox Boost Pump (OBP) design leverages 3-D additive manufacturing to make many of the key components. The housing is a single printed aluminum part and all of the stages of the hydraulic turbine are printed from Monel, a nickel alloy. This manufacturing approach allows the integration of complex internal flow passages in the housing that would be much more difficult to make using conventional methods. The turbine nozzles and rotors are also 3-D printed and require minimum machining to achieve the required fits.The OBP was first demonstrated last year in testing, where we validated its interaction with a main pump. The second iteration of the OBP for BE-4 is now in test. We’ve also just finished assembly of the unit that we’ll install for the first all-up BE-4 engine test.We’ll keep you posted on how our BE-4 powerpack and engine testing progresses.Gradatim Ferociter!Jeff Bezos
Powerpack test to that in less than 6 months would be quite an accomplishment.