The Raptor 3 engine has much better performance than the previous two rocket engines, and yet it looks much simpler. Typically things seem to need to get more complicated in order to get better. The trend seems to have been reversed here. Why?
In: Engineering
Because a huge amount of work has gone into streamlining it. Flanges have been removed and replaced with welds. Complex shapes are reducing the total number of parts. Each of these steps takes off a little weight, and that’s worth a lot to a company that can reuse their rocket motors.
The main difference between the Raptor engine variants that determine performance is chamber pressure. It looks like Rapor 1 had 250 bars, Raptor 2 had 300 bars and Raptor 3 had 350 bars. So if you manage to make the chamber stronger you can have higher pressure and higher efficiency.
Rapror 3 is likely more complex in regards to manufacturing methods that create an engine that is strong enough and can handle the pressure.
What has not improved a lot is the specific impulse, that a measurement that is close to fuel efficiency in a car. It is 350s in Raptor 1, 347s in Raptor 2, and 350s in Raptor 3. It is lighter so less mass you need to accelerate and have more thrust so you might need fewer engines.
When you build something new you quite often end up with something quite complicated with lots of parts to begin with. The initial goal is to make it work. When the initial version was developed they will have found different problems that needed to be solved and each solution might have added some part, You will end up with quite a complicated system. Even during the design process, the engineer might have realized we could make it better or simpler by doing it in another way but that takes time and requires a lot of man-hours of work. When the goal is to make a device that works you can’t spend too much time to improve it because then it will not be finished. You need to build a device that works.
When you have a working device you can spend time making is simpler and more efficient. At this point, you know what is needed to make it work, so you can just spend time making the working parts simpler. Do that and test is and you can create a new and better version that can be made and then you can spend time to make it even better. You might realize some part is not needed at all or can be removed if another part is altered. All this takes time.
We usually do not see the prototypes only the final product that is refined for mass production. Space X quite publicly tests prototypes so we can see this process.
Musk has been very open about wanting to continously simplify important components, believing that a simpler device is inherently more reliable.
Only time will tell.
Because a lot of the tubing is now a part of the main body because the engine is being 3D printed, allowing them to create internal channels for all the fluids. But also by removing some stuff
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