Why don't rocket engines melt? How engineers keep engines cool

During the Apollo program, when I was about 13 (1970), I was curious about rockets. I went to the library and found two books on rockets. I remember reading about regenerative cooling, and a light went off in my head as I was provided the answer to such a difficult problem in two seconds. The problem seemed exotic and insurmountable, yet it was ‘handled’ with a simple and elegant solution. I went on to become a structural design engineer from that initial effort. Hope you reach 10,000 such young men and women.

Literally since I was a kid, I was curious about that dark section of the F1 exhaust. I'm 55 now, and this is the first time I've had it explained to me. Thanks so much Tim, and thanks for all your work.

Watching your video, “Why Rocket Engines Don’t Melt”, with my grandson, who is a student at CalPoly studying to be electrical engineer, he said, “grampa, Tim should be an engineering teacher at CalPoly. Tim explains information not only very clearly and understandable, but speaks in a pleasant and comfortable manner that makes his presentation interesting”. Thank you Tim for providing your time and energy to help educate the public. You should feel good and proud of yourself.

Hey Tim, I find myself very fascinated and as of lately, pretty passionate about learning about rockets. I haven’t yet found any other videos as helpful or easy to understand as yours. Thanks for really bringing space down to earth for everyday people like me! 👍🏼 Your channel is a huge part of my growth in knowledge on space exploration and I’m so grateful for that!

These transitions are like next level. The writing and structure of this video is like A++. Well done to the team.

The idea of keeping super cool and super hot things so close together is crazy to think.

Very educational. I love how Tim makes very complex concepts fairly easy to understand. His illustrations really help. Nice job Tim!

This is easily one of the best videos I've ever seen on YouTube. When you said "this is rocket science", it blew my mind that you were presenting the information in such an easily accesible way. Instant subscribe.

Very fun to work on this one, I hope everyone liked the animations! 🔥❄🚀

Jet turbine maintenance engineer here, we use most of these same methods to prevent aircraft engines eating themselves. Primarily film cooling though. Most engines tap off high pressure bleed air from the final stage of the compressor (which is already at around 300°c or more to cool the hot parts of the engines. Effectively in a turbine engine the combustion gases will NEVER actually contact any of the metal parts as they'd simply burn through it in seconds. Most impressive one being that the turbine blades are grown from a single crystal of titanium, are hollow to utilise the regenerative cooling via channels inside and then vent those hot gasses via tiny holes in the surface to maintain a film of gas in between the blade itself and the combustion gases, all while spinning hundreds of times a second

Fantastically informative. I loved the graphics explaining the principles, combined with close-ups of actual engines employing those principles. Great job!

Thank you! I’ve wondered my whole life why the Saturn V engines had that top section of black exhaust. I’ve searched and this is the first time it was explained.

Just amazing. I'm an aerospace engineering student and I learned so much from this video, especially through the examples from history and the amazing animations, thanks Tim! One of my favorites for sure. Besides I'm studying applied thermodynamics at the moment so the timing is also spot on!

One thing amaze me about rocket engines is that there are drive shafts between the turbines that mechanically transfers momentum to drive the propellants against the high pressures in the combustion chamber. It's not only pipes but also mechanics.

I love the explanations Tim Dodd gives. At the start of the video he says the point of rocket engine is to develop pressure which equals heat. I've long been a science nerd and that is one of the best simplest explanations I've ever heard.

There are many YouTubers like this guy who produce apparently decent technical content like this while they have absolutely no experience in the fields they cover. I remember a couple of years ago, this guy was just a happy SpaceX fan who knew almost nothing about space technology or engineering... After persistent coverage of SpaceX tests and launches, he became popular for his nerdy reactions and his OMG screams during launches and tests. Watch his early coverages of SpaceX launches; he first knew about much of this stuff from reading the live comments (I personally witnessed that in a few instances). Now, he tells the audience to "ask me any question you have" :) It's amazing...

One of the few channels I don’t hesitate to click on. Thank you for the hard work Tim, you truly inspired me to get into the nitty gritty of rocket science.

I love the approach of this video following the engineering approach: Engines get very hot, we need to cool them. What possibilities are there? What works best? What can be combined? ... Great job, Tim. More of that please.

This video is so well put together that it could be used at a Technical School. Well done Tim!

You explained these cooling methods so well that feel like common sense. Anyway, the film method blowed my mind, I would never guessed how it works. Thank you so much for helping me to understand such a critical part of a reusable engine.