Hi there and thanks for posting, glad to hear you like them. If you haven't already done so, please don't forget to subscribe - it helps us more than you might think and ensures you won't miss our next upload on the A4/V2 missile. KR RJD A&NTV
When a man knows what to say and what to do... He does it with awesome precision.. without a second thought 🤔 this man is a legend in his field... He made a 35 minutes video look like 3 minutes.
Hi there, and thanks for that. But as my wife likes to remind me, I'm only a legend in my own lunchtime. Thanks again for the good thoughts. KR RJD A&NTV
Hi there, and thanks. Me too! I've been spinning too many plates, it seems, for the last couple of years - like many others whose business affairs and family welfare took a hit during the C19 pandemic. It wasn't all bad, but the workload was much higher than planned. Not long now - please stay tuned. KR RJD A&NTV
I have been a modeler and rocket enthusiast for most of my life. I am 60+ now, and I have not seen anything as detailed, concise, and straightforward as this video in explaining how the V2 rocket engine actually worked. Respect and thanks.
Thank you Robert! Was giddy like a kid on Christmas when this popped up in my feed. Cannot wait for the next video as well as the long-awaited Turbopump Part 2.
Hi Slarti, nice to hear something brightens your day in the gloomy hyperspace caverns of Magrathea. And yes, I know the two incoming ICBMs that you have playfully ranged at me are just a courtesy detail, and of course, I won't take it personally. Thanks for posting. KR RJD A&NTV
Fantastic. I've been waiting for another installment in the V2 Rocket series. I'll watch this tonight. Any plans to do more CSI photo analasys videos as I really enjoyed that content? Cheers Tony.
Hi Tony and thanks. Yes I've got a couple planned, and I want to do a short follow-up to the first one, as we've had some great feedback from eyewitnesses. One, in particular, sent me family pictures of parts from the St Stephen's road missile that fell in their garden! And I've got to show people these pictures. Thanks again for posting. KR RJD A&NTV
Hi there and thanks! That's me talking when I find a V2 paper buried in an archive or a new - old - piece of the missile! But maybe we both need to get out more and amongst 'normal' people? And then again no. Thanks again for posting. KR RJD A&NTV
Damn, this is the most wonderful rocket videos on the internet! I’ve seen a lot of them. I just asked a question in your short, through which I discovered your channel, about this injector design. But after watching this video’s couple of minutes I got all answer!!🎉
Very well researched video probably the best one on the internet. Those rocket engine models are incredibly detailed , up-close I can see layer lines I guess they are made by powder bed fusion technology, please make more videos like this THANKS & REGARDS ROBERT👍
Hi there, and thanks for taking the time to post, I'm glad to hear you liked it. I'm always pleased to be on the receiving end of thoughtful praise even if it's excessive! If you haven't already done so, please don't forget to subscribe - it helps more than you might think and ensures you won't miss our next upload on the A4/V2 missile. I've made enquiries with Accura about the exact technology used and will get back to you here shortly. KR RJD A&NTV
This whole series has been immensely fascinating. Thank you so much for all the time and effort put into this whole V2 series. It deserves SO much more attention then it has. I think the long periods of time between uploads involving this series in particular just didn’t jive well with the RU-vid algorithm as some of the videos I believe were from nearly 10yrs ago, but in any case I subscribed because the way you explain, demonstrate, and provide visual models of all the concepts are INCREDIBLE. I would love to learn more about other early rocket engines in just the same manner as you’ve presented your expertise in the V2 🤗 Please don’t give up, you quite literally made my day when I started with the turbo-pump video and simply needed to watch more. The effort you’ve put into this series is genuinely a treasure
Thanks for the goods on your channel - a lot of work in these videos - in the background and the making the videos themselves - appreciate the historical side and the effort put in.
Impeccable presentation even for people who are not familiar with technical details. The model shown in the video looks amazingly realistic. I wonder if this company has a large variety of rocket engine models 🤔
Thank you for these challenging videos. Thanks to your clear and understandable pronunciation, I can understand most of it despite the lack of subtitles - and yes, I'm German. As a retired engineer, I stumbled across your videos by chance and follow them with great interest.
OH MY GOD!!! I thought this series was dead! I so enjoyed the turbopump video and was looking for part 2 for so long. I finally gave up. I am glad to hear it is still planned! Do you have any idea how long it may be before it is released?
Another amazing video by Robert J Dalby. He as lots of fans including me. An interesting RU-vid video is "High Level Introduction to the V2 Rocket Design". Some questions: Does acceleration help turbo pumps pump fuel? Does that make the pumps go too fast? Compressed air is used to fill the tanks with gas as the fuel is used. Can too much compressed air in tanks cause the tanks to rupture? Are the oxygen and fuel valves closed after the burn? What runs out first? Is it Sodium Magnate? Is it Hydrogen Peroxide? Is it Alcohol? Is it Oxygen? If oxygen or fuel run out first does that mean the turbo pump will self destroy due to increase speed? Does going back to earth cause heavy vacuum in burning chamber and in piping? Does air pressure get into the inside of the rocket as it descends? Can high vacuum and internal air pressure cause pipes and tanks to collapse during descent?
Hi and thanks for the interesting questions. Imagine you took a plastic water bottle and made a small hole in the lid. Now turn the bottle upside down - of course, a steady dribble of water starts. But now, jerk the bottle up and down. With every upward move, you get a jet of water; on the down motion, just a dribble again (even less than the static flow). The V2 had an open vertical pathway from the propellant tanks to the injector orifices. If a little man 5mm high was unfortunate enough to find himself in either empty propellant tank, provided all valves were open, he could walk, scuttle, and climb from the tank outlets down through the feed pipes, through the open spaces of the turbopump (TP) and find himself peering through the LOX or fuel injector holes. And he'd have a good grasp of the propellant flow pathway and its similarity to my crude plastic bottle analogy above. And how vulnerable it is, in principle, to influences from the motions of the vehicle - he'd still be quite cross with whoever put him in the tank though. The actual increase in flow from the steady acceleration is insufficient to provide a constant forward feed pressure for the TP and both tanks required pressurisation to achieve this adequately for the entire duration of the boost phase. And this is part of the answer to your second question: no, pump speed is determined by the steam supply not tank pressure. Tank pressurisation: in addition to compressed air 100% boiled-off oxygen is used in the LOX tank, and at lower altitudes, a ram air pipe was used to pressurise the fuel tank. The V2 tanks were indeed fragile, if the tank was filled while laying horizontally, it was likely to distort and rupture. But to the best of my knowledge, vehicle losses due to tank overpressurisation were not recorded in test flight data. Besides, the open propellant flow pathway means increased tank pressure would tend to resolve as increased chamber pressure, leading to increased velocity. Both are typical irregularities with the V2 as these functions were not specifically controlled. Usually, the valves are closed, and the tanks are kept at around 1.5 times atmospheric pressure to avoid collapse. Nothing runs out as such; the length of burn is determined by velocity, not propellant availability - though this, of course, is a range-limiting factor. A propellant feed interruption or reduction in flow is potentially disastrous for the TP. It can lead to excessive rotational speeds (due to lack of resistance) that can destroy the engine. TP shutdown was initiated if the rate reached 5000 RPM. Make sure you catch part 2 of the TP video to see a more complete explanation of the overspeed switch. I hope this helps. Thanks again for posting. KR RJD A&NTV
@@RocketPlanet Thanks for the reply. Where is the ram air pipe used to pressurize the fuel tank? According to the RU-vid video "High Level Introduction to the V2 Rocket Design", the fuel tank was pressurized by compressed air tanks, not a ram air pipe. My understanding is that the V2 rocket weight 5 tons without fuel (I assume fuel means the alcohol and oxygen), and has 9 tons of fuel giving a gross weight of 14 tons. I think that the initial burning using only gravity (turbopump not running) provided 12 tons of thrust which meant the rocket did not move. My understanding is that when the turbopump ran then the thrust went to 25 tons. I figure that with 25 tons of thrust then 11 tons was used for acceleration. The formula for acceleration is a=F/M. I figure that acceleration was 11 tons divided by 14 tons or around 0.8 G. So with 1 G for gravity, the rocket experienced 1.8 G of acceleration (the fuel was forced down to the turbopump by 1.8 G). Near the end of the burn the 9 tons of fuel was almost gone so the rocket weighted 5 tons. If the thrust remained at 25 tons throughout the burn then near the end of the burn when the rocket weighed 5 tons then there was 20 tons of thrust for acceleration. That means 20 tons divided by 5 tons gives 4 G. I would think that would be a significant assist for the turbopump causing it to substantially increase in RPM. At the end of the burn I think the rocked is level so gravity is no longer a factor. I would also think that the thrust of the rocket near the end of the burn would be substantially greater than 25 tons due to the assist of increased acceleration. That would mean the G forces near the end of the burn would be substantially greater than 25 tons. You did not comment on what I believe could be a factor causing some rockets to breakup during the flight. That is the vacuum in the back of the rocket due to high speed through the atmosphere especially close to impact. In other words there could be a pressure of 15psi trying to crush pipes and tanks (I'm not sure how air could get into the inside the rocket which could mean that the skin of the rocket could be crushed by the 15psi atmospheric pressure). Could that explain the crushing of pipes around the thrust chamber as seen in your RU-vid video "V2 Rocket - Photo Analysis "?
Hi Peter. The ram pipe exits at the warhead, halfway between the fuse tip and the base and ran through the explosive filling, connecting directly to the alcohol tank. The fuel tank was pressurised by compressed air initially and a ram pipe after the missile had achieved significant velocity. Fuel = alcohol. Propellant = alcohol + oxidiser Primary stage burning, gravity fed, produced a thrust of around 3 tons. Due to altitude and the reduction in atmospheric pressure, the thrust rose to 27+ tons. Turbopump (TP) RPM was a function of the steam generator, thrust chamber pressure could be affected slightly by propellant acceleration. The pressure on either side of the skin of the missile was equal at all times - equalisation vents took care of this. I think a hard vacuum was created at some locations in the engine as combustion ceased (engine shut-down was an uncertain process event on the V2 at the best of times). However the best explaination for the violent crushing of the smaller film cooling pipes is a phase transition of the fluid transported by the pipe shortly after engine shut-down. KR RJD A&NTV
Good video, but I wish you could have detailed the single piece 'shower-head' injector plate they were experimenting with toward the end in order to replace the 18 separate burner cups. It's often erroneously illustrated as the service version in an extraordinary number of 'reference' books!
After the war, USA, France and USSR put a great deal of effort into assimilating the German know-how. An interesting thing is that the Germans working in France have never figured out how to make the engine with the shower-head injector to work reliably. It worked, but half of the launches ended up in failures. Eventually they invented a completely new geometry, which was so successful that it stayed on for decades in French designs, all the day to the Viking engines used in Ariane and to the still flying Indian engines.
Thank you for your great efforts. Although, I'm a computer engineer, still the content was very interesting to me, and I felt the efforts put into making that.
Hi and thanks. Don't forget to subscribe if you want to see more like this - and be sure to take a look at Turbopump Part 2, which looks at some surprising physical effects of the pump system on the rocket in flight. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-CmTxAFY03fU.html Best wishes A&NTV
Rather than using injector cups, did they ever try a large injector plate with separated, walled off zones to provide the combustion instability prevention property of the cups without creating a plumbers nightmare? Or was that just a much later insight of the Saturn F-1 engine designers addressing its combustion instability issues?
The Germans were developing the technology from scratch, and started from very small engines. von Braun himself wrote a dissertation on experimental work in engine development. Afterwards other specialists quickly scaled the engines up to a larger size, but they got stuck at 1.5 tons of thrust. No matter what they tried, they could not simply scale the size up beyond this. So in desperation they started to combine several of these already perfected 1.5 ton engines to make them work to a common nozzle. This way they were able to achieve first 8 tons, and then 25 tons of thrust. But this was obviously a half measure, and the research on other variants continued. Towards the end of the war, they were readying production of engines with a flat injector plate. There are many drawings of them, but it is not clear how well they actually worked.
Great model and you describe things so well what gets me about the real thing is just so heavy the thing looks I would have thought they would make this thing as light cheap and simple as possible as it is a bomb a one-off.
Could part of the reason for the longer curved sub-pipes on the bottom be to also just give them more leeway during assembly when they are all being connected and thus less stress on the parts? I mean aside from it being primarily for stress from temperature changes.
Having bent miles of stainless tubing in a 45 year career, I can testify that the oxygen tubing would be a nightmare. Cross threading and bad seals due to deformed tube ends would be common. Add in aluminum/steel threads and the only thing that could be worse is if they used fine threads.
Given the fact that all 18 pre-burner chambers are welded to the injector head already. If the lox feed pipe are such a problem, why can't they just weld/braze all the joints as well?
Hi Brad. Many thanks for supporting my work - I appreciate your contribution. Every donation like this allows me to go on producing high-quality content on a subject that I'm passionate about, and there is a lot more to say. Best wishes Robert J Dalby
V2 is undoubetly a delicate and complex engineering design of its time. I have always wondered how the Germans were able to set up the production of these rockets staffed by unskilled POW workers? Seems to require strict tolerances to work properly. How did they set up mass production under such simple conditions with resonable reliability?
