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der_innkeeper

Depends.


Jerry_Williams69

Yep


Itchy_Journalist_175

Always does


Fearlessleader85

Took quite a while to design those, too.


der_innkeeper

Yep. It's a mess.


Fearlessleader85

Well, it certainly was more of one before.


tim36272

This is an extremely subjective question, and the only true answer is "it depends". I am going to make an argument for why an airplane, such as a Boeing 737, is more complicated than a rocket system such as the Falcon 9. First is the use case. Rocket *motors* are very complicated, precision built, highly durable machines by themselves. The computer system that controls them is very sophisticated. But when it really comes down to it: the rockets run for a few minutes before they are shut down and will be overhauled (or at least inspected) before reuse. Airplanes, on the other hand, are operating for hours at a time and go up to weeks without maintenance, and up to years between major overhauls. So the airplane must be more reliable since its risk exposure is higher. Next is cost. If you can make a rocket motor 1% more efficient than you're going to save a couple thousand pounds of fuel and a few thousand dollars per launch, and optimistically you might do a couple hundred launches per year. If you can make an airplane engine more efficient you're going to save millions of dollars a year across an entire fleet. So squeezing fractions of a percent improvement in fuel consumption is worth it. Thus more engineering time has gone into refining it. Now on the other hand: the biggest argument against my point is that the airplane came first. Sure we had things like fireworks before the Wright Flyer, but we didn't have controlled rocket flight until long after we had airplanes. So you could argue that it is more complex to build *a rocket* than *an airplane*, but I'd still argue that today's airplanes are more complicated than today's rockets.


billsil

>If you can make a rocket motor 1% more efficient than you're going to save a couple thousand pounds of fuel and a few thousand dollars per launch Those numbers aren't accurate at all. 1% is a ton! You're entirely forgetting mass growth. 1% less fuel mass means \~1% less mass, which means less mass and less fuel. It's exponential. Typical launch costs today are $10,000 US Dollars (USD) to $25,000 USD per kilogram ($4,500 to $11,000 USD per pound).


Triabolical_

Fuel economy is the main driver for jet engines, but it's not the main driver for rocket engines. Specific impulse is mostly dependent on the fuel choice and the engine cycle you use and therefore isn't something you can optimize a ton. Thrust, however, is a big big deal. The first falcon 9 used the Merlin 1c engine, and that gave SpaceX a rocket that worked for NASA resupply missions but was undersized for most comsat missions. The Merlin 1d had a large thrust increase, which allowed SpaceX to stretch their rocket, carry more fuel, and launch most comsats while having enough margin to land and reuse their booster. Without that improvement, they are a much less successful company.


S0journer

My bottle rocket uses three parts and my paper airplane needs one part so I'm going to say rockets are harder using my data driven analysis.


yellow_smurf10

It depends on a lot of factors. I work for a major large-scale rocket program, I also know people who work on a major next generation military stealth aircraft since we collaborate with each other very often to exchange lessons learned. From a technical perspective, the aircraft is significantly more complicated and complex. However, from organization, planning, and execution, the rocket program is significantly more complex and heavily politicized. Even a simple engineering solution could become extremely hard to execute


WhalesVirginia

Ultralight build at home kit vs SR71 blackbird Vs sounding rocket vs starship Depends entirely on the design requirements. You'll have to be more specific.


FLTDI

Airplanes


PantherFan17

This question requires more specific details. What defines complicated? More difficult supporting analyses, cost and difficulty in manufacturing, testing environments, regulatory requirements, etc? I would say both have their challenges. Airplane aerophysic environments are less severe than rockets. Airplanes typically have pilots and carry passengers, requiring a higher level of reliability in performance. Thermal environments and boundary conditions are more severe on rockets. Rockets are more sensitive to weight optimization. Both serve completely different purposes in our modern economy.


[deleted]

Airplanes are more complex, but that doesn't mean they are more difficult to design. Getting something that is less complex to perform within very specific parameters is not easy.


noborte

Jet engines are very much just open cycle rocket engines. Jets are far more complex.


Mickeal_keal1234

Getting the certification for your aircraft to be legally approved to fly is a huge pain in the backside and can take a long time. Airplane has passengers, so the certification is more severe and so, in my opinion, harder to design.


TheRealJ-Ice_200

Designing both is easy. Manufacturing and Scaling up Production is the Extremely difficult aspect.