Aerospike Engines - Why Aren't We Using them Now?
Вставка
- Опубліковано 26 тра 2018
- brilliant.org/CuriousDroid
Over 50 years ago an engine was designed that overcame the inherent design inefficiencies of bell-shaped rocket nozzles, but despite much research in the 60's, 70's and 90's and was to power the replacement for the Space Shuttle. But 50 years on and it still yet to be flight tested. So why aren't we using Aerospike rocket engines?
This video is sponsored by brilliant.org/curiousdroid
The first 200 people to apply will get a 20% discount on their yearly Brilliant subscription.
Presented by Paul Shillito
Written and researched by Paul Shillito
Intro music by Mike Mullen BMI www.positrosmic.com
Footage and Images - NASA, SpaceX, Rocketdyne, Lockheed Martin
This episodes shirt is the Madcap England Wallflower - available here www.madcapengland.com/product.... - Наука та технологія
When I was employed at Rocketdyne I worked on the design of this beautiful rocket engine!
That's what they call compartmentalization that's why your right hand never knows what your left hand is going to do with it and neither does anyone in it Bingo Homeland Security
I was on The Hill digging through a warehouse , probably ETEC, for some directed energy stuff and I look under a tarp.... HOLY CRAP a flippin linear aerospike just sitting there! Amazing. I climbed on top of it and poked around a bit, why not. I wonder where it went when everything was hauled off.
I was fine with developing the aerospike engine but the X-33/Venturestar was about developing far too many technologies in one demonstrator to expect success during the limited period of government financial support. It was too many eggs in one basket, they should've done something like the Delta Clipper with the option of a ring aerospike but designed for a conventional engine. The goal of establishing a crew launch vehicle should've been the main consideration given the complexities of the Shuttle and the obvious need to replace it.
You guys did some good work. I supported X-33 here and there in the 90’s a little. Too bad Lockheed tried to implement too many technology jumps in X-33. Being a shuttle tile engineer, i found it interesting LM was moving toward metallic TPS. Funny though, even LM abandoned the idea and are using ceramic tiles on their Orion capsule. Sierra Nevada is using ceramic tiles as well, and we hear Elon is moving toward ceramic TPS too. It would appear there isn’t anything better than the 60’s technology ceramic insulation for use on entry vehicles.
When i was employed with Skynet... we had bigger plans!
Why is every problem related to flying engines is always "the developer went over budget"?
Because the people funding the projects care about cost and bottom lines, instead of science.
@Justin Rowe depends on why im investing. For profit sure. For the advancement of tech and our species, that shouldn't have a limit.
Check out the movie "Unacknowledged", might give you all a hint to what's actually going on.
Indeed money is important, but only because money = power to rule.
@@cpthindsight1894 that's obvious, it's a monetary system designed for class suppression. Debt is indentured servitude.
@Justin Rowe that's true. Even Elon musk is having to follow the most proven methods for space travel. Due to cost and profit. Regardless of how much he wants to develop new tech. He's still locked in the economic system.
After graduation (BS, MS engineering), I landed a job that partly fulfilled my dream to be an astronaut. Rocketdyne was then a division of Boeing. I went straight to advanced programs as a member of the XRS-2200 Engine, which is the Aerospike engine we see featured in this video. The X-33 faced a problem. The fuel tanks would not withstand the required fuel pressurization. Benefit to cost issues also started to make NASA lose interest. Yet, as the premier liquid engine propulsion in the World, Rocketdyne delivered. I had already jumped to Atlas and Delta propulsion, then the Space Shuttle Main Engine when I visited the test stand (B1, if I recall well) being set up for test at SSC. Extensive data was collected, and improvements in performance were noticed. These data will someday be helpful for an entity that is serious about the Aerospike. By the way, we need to encourage the newer generations to study science and engineering to keep the edge. God bless.
Thank you for not only your excellent work, but also your faith to give your upmost as an engineer to the Most High!
Unfortunately, with the break-down in society (specifically the highest, by-far, divorce rates in the world) kid's in the US no-longer have the schooling & home discipline, or even desire to pursue the hard sciences as they once did in your generation...Most military personnel in high command now consider this to be a national security concern 😰
@@gregsayles9253 Oh stop whining, Greg. Nobody wants to hear you complain.
40% fuel saved does not means only fuel cost saved, it means less mass, nearly 40% less mass, so much more deltaV, much more utility mass.
true,that leads also in using just one aerospike engine instead of multiple engines in different stages,so also less weight for additional engines without also having the problem of dealing with returning stages.
Are you an engineer ?
@@Wrongway346 it is the very basis of rocket science: at the ignition the engine must lift all the rocket including all the fuel, so the consomption is higher. If you need to go at 200 km orbit for example, you need a powerfull enough engine, but now you need the fuel to feed it, and now you need a more powerfull engine, and more fuel, etc. The result is massive rockets with a mass/power ratio making posdible to reach the wanted orbit. So, an engine more efficient is extremely interesting, because less fuel means a big down sizing for the same purpose
also single stage spacecraft would mean no complex staging and less travel planning. You just need to actually pilot the ship towards your destination without timing every stage operation
@BRRP Yeah, I think it's easy for people to second guess what's being said. It sounds like the efficiency to mass savings calculation was already done. The engine probably isn't 40% more efficient, but even a marginal increase in efficiency rapidly pays dividends in rocketry.
From a spy to a science presenter, you impress me Lord Varys.
You beat me to it...
Lmaoo
SPY MASTER!
He was a spy?
@@rimple1158 he is a eunuch
I love the way you present it, it looks like a mix of history class with engineering class
jordan couldn't have said it better! he beats all the network TV shows related to those topic's!
Good music too, nice to hear and not to distracting.
AwesomeBlackDude Flat Earther its called Mathematics!
AwesomeBlackDude can't you read? I meant you being a Flat Earther! because you are questioning how it was done that the van Allen belt was discovered. It is called mathematics!
Engineering history is best history!
if save 40% fuel w/ aerospike, doesn't that mean more payload?
People are pointing that out a lot in the comments and it would have been nice if Droid mentioned that in the video. That's less fuel needed plus you only use one engine means a much lighter vehicle. I don't know if it's enough to offset development costs, but it sounds worth looking into. That being said, these companies employ a lot of very smart people so it probably has been looked into and something about it doesn't look good enough to go after.
You also have to factor in mission flexibility of SSTO on a reusable craft. Faster turnaround and you can potentially land anywhere with a long enough runway.
much, much more payload. Weight of propelant is biggest issue with rocket
Doesnt necessarily mean more payload, it does mean that more of the mass the rocket launches with can be something other than fuel such as payload.
So the answer is: Money
And bureaucracy
@@Ali-kp7bh no, I mean bureaucracy
It disgusts me that companies are too concerned with having maximum profits to make progress. That's all any business today cares about is maximum profit, getting every single penny they can squeeze out of something.
@@roselockecottage6486 not that simple. how you gonna fund your next launch? rockets are expensive, friend.
@@NaeroSpace corporations can afford it. They choose not to invest because they are only concerned with making *maximum* profit. If a huge profit can't be made they aren't interested and I find it gross.
Sometimes the internet gives you a random video and then you stumble upon this gem. Very informative, very clear explanation. Thank you, Sir!
It is good for near orbit.
Black blackground is far more relaxing for eyes than white. Great change.
I 100% agree
Green screen reflection...
All that aside... Great mix of history and engineering...
russian bias confirmed
That depends on whether or not the white on the screen is reflective or emissive.
Subtle, aren't you?
Aerospike can still be used for non-SSTO rockets.
With SpaceX they can use it on the 1st stage part of the rocket and if the 2nd stage is needed to land then they can use the Aerospike on it as well.
Some crazy reusable rocket that lands in different atmospheres as part of a mission to multiple bodies in one trip, Aerospike is the way to go.
Google trends shows aerospike at 100 percent at October 1 after everyday astronaut's interview with Elon.
There is a big Achilles Heel with the aerospike nozzle that is not talked about much in the technical literature...but is fundamental to fluid mechanics...
It has to do with the surface to volume ratio of any heat engine or nozzle...a big engine will always be more efficient than a small engine, all else being equal, due to the fact that internal surface area increases only by the square, while volume increases by the cube...
The surface area is where viscous losses occur [friction losses in the boundary layer of the flowing fluid at the wall]...while the volume is what determines mass flow, which determines power...
If you increase engine [or nozzle] size you decrease the surface to volume ratio which means less fluid comes in contact with the wall [in proportion to the mass flow], and your boundary layer is small compared to the volume and mass of fluid you are moving...
With the aerospike design you greatly increase the surface area for any given mass flow, compared to the standard bell [de Laval] nozzle...
You can see this by by looking at the two respective geometries...on a bell nozzle the sonic throat surface area is much smaller than on an aerospike 'toroidal' [axisymmetric] design...where the flow has to go around a donut-shaped center body in the middle of the flow...[also you now have two surfaces, an inner and outer, as opposed to just the outer surface of a de Laval sonic throat]
The result is that viscous losses will be much greater in the aerospike...thus increasing pressure loss through the nozzle...as more of the fluid has to 'scrub' against the donut surface...
Nozzle efficiency is directly a function of pressure loss...so you want to have as little pressure loss as possible...we recall from basic thermo that only pressure energy can be converted directly to work energy in a heat engine...so pressure is the 'coin of the realm' in any heat engine...
The 'linear' [2-D nozzle] aerospike concept is similarly bad in that respect, perhaps worse...you can see that you have, in effect, a whole bunch of little 'nozzles' lined up next to each other and directing the flow against the central 'spike'...
This is like having a whole bunch of tiny little nozzles, as opposed to one big nozzle...one big nozzle will always be more efficient for a given mass flow than a number of smaller nozzles...again for the fundamental principle of surface to volume and the resultant effect on viscous losses...
This is one of the reasons why the F1 engine was so effective...it had one huge nozzle...even though it had relatively low chamber pressure [about 1,000 psi...barely a quarter of what Russian high pressure engines achieve]
The difference in surface to volume ratio of an aerospike engine compared to a conventional nozzle would be at least an order of magnitude if not more...
That is one of the reasons we have not seen continued interest in the aerospike...it is fighting the laws of physics...
Another aspect that is not mentioned is chamber pressure...an engine with higher chamber pressure will be less sensitive to the losses that occur as a result of a flow that is not perfectly expanded at all flight regimes [ie altitudes]...
This is due to the fact that higher chamber pressure requires a larger nozzle area ratio...[the ratio of the exit area at the base of the bell to the sonic throat upstream]...
The higher your pressure, the longer the bell and the bigger its exit area...which means that the compromise at off-design ambient pressures will be less severe...ie you can select a bell length that can perform well [although not optimum] at varying altitude...
We saw this in the design of the hydrogen-fueled Shuttle main engines [RS25] which needed to work from launch to space...the engine achieves a chamber pressure of ~3,000 psi...using a fairly complex two-stage turbopump...
With the high pressure the nozzle was able to be sized as a good compromise at all altitudes and ambient pressures...from SL to space...
This is one of the reasons that Nasa concluded in the early 1980s that high pressure kerosene-fueled engines need to be developed...something the Soviets had already done in the 1960s with the NK33...
See Nasa technical report 19820002372
'Fuel/oxidizer-rich high-pressure preburners [staged-combustion rocket engine]'
However this has not happened...high pressure engines are not practical on the simple gas generator cycle which dumps the exhaust used to drive the turbopumps overboard...a staged combustion cycle is required...[as on the RS25 and all the Russian high pressure engines]
This, in turn, requires advanced turbopump capability...supposedly the BE4 engine in development now will use a staged cycle [with projected chamber pressure about half that of the Russian engines]...but SpaceX engines use the gas generator cycle and the company does not even make its own turbopumps [which are made by Barber-Nichols]...
Another issue with this video is that the single stage to orbit concept is tied in with the aerospike engine...which are really two independent ideas...
There are many different schemes and concepts for SSTO and the issue of nozzle performance is not even the major factor here...it is about the mass ratio...
We see this in the Tsiolkovsky rocket equation where delta v = specific impulse * gravity * natural log of mass ratio...
So we see from this relation that at a given engine ISP it's all about the mass ratio..ie the fundamental problem is still how to get enough fuel and oxidizer on board to get you to orbit in a single stage...
Even if you could make the nozzle more efficient by addressing the altitude problem it does not follow that you have solved the mass ratio problem...
Another point that is overlooked here is that any bell nozzle could conceivably achieve perfect expansion at any altitude IF the chamber pressure is somehow able to be varied...this gives the same result as changing the nozzle geometry to compensate for altitude...
For instance at SL launch we can use a lower chamber pressure to prevent overexpansion and increase pressure as we climb out to prevent underexpansion...
Of course this would be quite tricky for the turbopump as turbomachinery is also designed to have an optimum performance at a particular rotation speed and mass flow etc...
But the bottom line is that the aerospike is really a non-starter due to the viscous loss issue...and second, aerospike [or more broadly perfect nozzle expansion throughout the flight regime, however it is achieved] is in no way a 'solution' to the SSTO challenge...
Jet Guy - Cool read. Thanks for that. That's always the issue I had with the aerospike is that the expanding gas has too much to do before it actually generates thrust. So much lost energy through all the complexity. Bells for the win! I mean hell the aerospike doesn't even have the greatest isp. Jack of all trades master of none.
Jet Guy, Forty-five years after seeing that first photo of an aerospike on a test stand I've still never seen a proof-of-concept ballistic flight powered by an aerospike. The ground tests are so visually appealing that hard-boiled aerospace companies give the concept third chances. _Thanks for stating the flaw in the concept._ I'll still be on the lookout for that launch but more and more it looks like the flight realm may be confined to imagination.
Jet Guy - SSTO rockets must lift a lot of dead weight all the way to orbit, that multi stage rockets jettison after the fuel is consumed, improving the mass to thrust ratio each time a stage is jettisoned. Your very informative write-up indirectly states this, but for clarity, I state it directly.
Interesting thanks, food for thought, I am guessing there is a way around some of this within so called conventional physics, will be sleeping on this - many thought experiments as prelude to 'provoked' lucid dream states ;-)
Thanks again for your effort in describing this in good detail, hope you don't mind questions later on, cheers
Isn't it that you have more pressure at sea level and under expansion is the problem, with less at higher altitudes where overexpansion is the problem? Otherwise seemed very quite correct and obviously correct.
I did a highschool report on the Venturestar/X-33 program. Got in touch with people at Lockheed Martin in the program and alot of cool goodies including a very detailed wood model. 😎
I was crushed when it was cancelled.😕
There's just something mesmerizing about this guy's shirt on the jet black background. I can't tear my eyes away.
I think this is perhaps the best description of how atmospheric pressure affects rocket engines.
Thank you for helping me to understand this.
When you mentioned that it was "quite simple" I thought "I'm sure not going to understand it now", however you explained it very well so that even I could understand it.
It’s sad to think about how much aerospace technology was developed decades ago and not used since due to lack of financing.
with NASA funding being less than a fraction of US gdp, I bet that aint the issue... There's too much rich people spending money in useless luxury instead of funding useful science, useless wars and excessive expending, too much corporate lobbying... whatever. given the US government snail pace at funding space, it'll probably be private corporations to keep things going on, and other countries governments.
What makes you think it’s not still being used for current research and development? Just because NASA doesn’t show the public doesn’t mean they’re not still building spacecraft.
LazicStefan Man, you're fucking stupid.
FutureNow instead they waste money on gender studies because we dont know whos female and whos male.
LazicStefan Welfare? Really? That's what is sucking the money out of NASA? Couldn't possibly be the fact that our annual military budget is over $500 billion dollars.
your manner of speaking is pleasant and easy to listen to.
you do show your face, which i normally find super annoying when other presenters do so, but you dont hog the camera with ego and you only demand our attention long enough to get across the desired relevant info; never stopping to attempt comedy or worthless sideshow spectacle .
great work, thank you.
I feel the same.
Linear aerospike arrays look a lot like the Millennium Falcon's main engine...
George Lucas predicted it all !
Yeah lol ikr
Maybe Solo should learn what a parsec is.
The torodial aerospike engine looks like a naboo starfighter
@@nonamesupplied1875
See 'Solo - A Star-Wars Story' where parsecs are distance.
I think multi stage rockets are the better way to go. As he said, bell nozzles are more efficient for specific atmosphere. But the big advantage of multi stage is that it sheds vehicle weight as you climb. Less weight, the better. Why do you want to continue to carry all that mass all the way into orbit if you don't need it? Also, once in orbit, you have to re-enter the atmosphere, and that is when you really want the smallest and lightest vehicle. Smaller re-entry vehicle means less shielding, and less weight means easier to land.
Bro, when you take away all those stages away, how much less fuel do you need? Those stages are literally just engines and fuel tanks, anything without stages is going weigh less, fact. I am not saying aerospikes are the way to go, I am saying your logic is flawed
Actual science. Subscribed.
nice
The primary reason for multistage rockets is not to allow for different engine nozzle sizes, it's to shed huge amounts of weight allowing for a far greater payload to orbit. An aero spike is less efficient in a multistage rocket, as it's worse at both sea level and in vacuum. Once above the atmosphere you don't need the same thrust you needed at sea level to get off the ground, you just need very efficient continued thrust to build up your orbital speed. An SSTO rocket is by design an inefficient way of getting to space, and with full booster reusability just a year or two down the road, SSTO can finally be put to rest.
PortlandPhil or both
Here's a video by Everyday Astronaut on why SSTOs suck: ua-cam.com/video/Sfc2Jg1gkKA/v-deo.html
Where's my space elevator? Get it together, Elon!
Yes, that is very true.
We seem very biased to thinking of one-part vehicles. So we imagine hopping in our rocket and scooting into orbit 'cause that's like our everyday experience.
With chemical reactions, mutli-stage is the only practical choice. Nuclear propulsion is a different matter, but then we have other concerns...
Also, you might find this link interesting - jim-cantrell.squarespace.com/blog/2016/11/8/failure-is-the-seed-of-growth-for-success-lessons-learned-from-developing-and-testing-aerospike-rocket-engines
In particular, Jim states: "The point behind all this is that, while aerospike engines can provide performance advantages. The larger number of parts and components means that they are usually heavier than their regular bell-nozzle counterparts (in terms of thrust-to-weight) and, more importantly, require very high component reliability."
Consider a linear aerospike engine with 8 combustion chambers along each side -- that's 16 combustion chambers with attendant injectors, valves, controllers, ignitors, perhaps propellant pumps, and piping. Compare to a single chamber bell-nozzle design. Yes, the engine is more efficient at turning chemical energy into motion; however, the overall vehicle performance is worse.
You might want to look at the Linear aerospike stats. It was more efficient at sea level than a lot of standard boosters and as it rose became even more efficient and powerful when in orbit. There are some exceptions to this and they come from long term testing and design tweaking. If the linear aerospike had been in operation for all the same years I promise you it would have been improved to incredible levels by now.
I remember reading about these in the late 60's I think. Always wondered why I never heard about them again.
Thank you for making another excellent video. I found it easy to understand and follow the air pressure shaping exhaust concept. PS. I love the shirts and that new black background is easier on the eyes. Another superb "2 thumbs up" video!
That was unexpectedly informative. I don't know why this was recommended to me, but it was definitely worth my time.
word
It"s our common experience (that we just don't get how it ended up in our recommended video list) :)
Great to see you and those shirts in colour again :)
RumpelForeskin color*
Christian Colour is the British spelling and so is correct.
Colour is correct. It’s English, us English invented the language.
Indeed!
Darren Bailey Actually it originally comes from the French.
very well presented/hosted/narrated---brilliant video!
Glad you’re feeling better, miss your videos mate, I hope you keep it up, this video is very good
My first impression of your videos was, "This looks and sounds professional." You just got a new subscriber!
UA-cam recommendations finally got it right. Great video.
yeah, much better as "Pussy-Shaving/Waxing"!
It's kind of depressing in its way
@@MrP71 wut
Perfect presentation. congrats and thank you!
Stumbled upon this channel a few days ago, love it.
Well I definitely use them in KSP to make SSTO's
This is one of the videos I would not expect you to be on. :) It always feels like an easter egg seeing you somewhere.
Also KSP = 💯
Is this just a hobby to you, or some way to eventually commercialize yourself that I haven't figured out yet? Will we eventually see Justin Y comments with "this comment was brought to you by Brilliant dot org. Sign up today with promo code Justin to....."
Thanks, but i'll stick to RAPIERs & Nervs
Muscle Hank would just throw things into orbit
I'm seriously surprised at how informative this was and how approachable the information presented was. Fantastic!
The aerospike was the only thing I liked about the Venturestar/X-33 project. I thought choosing that project was betting on too many high risk technologies at one time and they would've been better off focusing on proven technologies to get back into space which eventually is what we're doing now. My choice would've been the Delta Clipper just to get back into space then work on the technology demonstrators.
I don't know who this guy is but like his shirts, his vlogs are really entertaining , fresh and new. Hats off!
I think the main benefit of fuel efficiency isn't saving cost on fuel, but using that to have a higher payload rather than having to carry that much more weight in fuel, and at the end of the day the payload is what makes you money. If you can save several tons of fuel that is several tons of satellite you can send up.
Yes. Also if you need same mass delivered - less fuel means smaller fuel tanks, smaller rocket and less weight in general (which means it's easier to construct) and so on.
Bingo. All of that space/mass saved in fuel can be devoted to extra cargo.
crisray6789
Alqubier- Fronin spacecraft is the future of space craft technology, anything else is just spinning our wheels.
It's all about the mass fraction savings. SSTO isn't possible without improved efficiency. SpaceX is betting that the operational complexity of a fully recoverable TSTO solution will be "good enough" to truly open the skies. If they can hit their aspirational cost numbers, they'll be right... probably igniting an SSTO race to do to SpaceX what SpaceX is doing to ULA .
Hey just wanted to say thanks for the quality videos...I'm so used to click bate vids with either little to no actual explanation or information on the topic said in Title...Cheers from the US! Keep up the great work (:
This was an absolutely fantastic description and video!
I've been fatally sick for 4 days clingy to life after being poisoned and your page helped me stay calm and get through it. I didn't even know I liked space. Thank you man just Thank you. I was so scared
Hey thanks guys I got out of the hospital and I am alive!
@emma harrington thank you I was suicidal and on drugs. I am no 3 months sober on 5/16/19. With out this his videos to keep my call I never would have made it to get the help I needed to get better.
Why looking at the price of fuel, when a kilo of fuel saved in efficiency, is a kilo gained payload?
Yes very true and that would be worth a lot more.
Troels Fischer Thomsen a kilo of fuel savings doesn't equate to an extra kilo of payload. It's not a 1:1 ratio
I think the more important factor is the rocket equation, fuel saving is really more than money, it's delta V
yeh i thought that was a stupid argument. Fuel efficiency doesn't mean you use less fuel, it means you use the same amount but get way more delta-V and therefor payload
Yes- weight is much less critical for the lower stages since they only undergo about a third of the acceleration. Fortunately the lower stages are the big, expensive ones and the easiest to recover. A reusable first stage is the low-hanging fruit, so it's nice to see SpaceX succeed at this.
Very well explained and a pleasant manner
You Sir enriched my day with this video. Highly interesting and informative!
Very informative and interesting. One of those random serendipitous things, lucky me. Well done Paul Shillito and team. Thanks
i was nder the impression stages were additionally used to dispose of empty weight, being able to drop 75% of the fuel tank weight seemed like a good tradeoff to make
That's the major reason for staging, but you'd need a lot more fuel if you use an engine bell not optimized for the atmospheric pressure you're flying in. This is why when they fly Delta IIs with 9 boosters, only six are ignited at launch. The remaining three have engine bells optimized for higher altitudes, and are ignited later in flight. I'd assume that if they used aerospike engines (not that they'd work with solid propellant, but for the sake of the argument), they could get better efficiency out of each engine, and could afford to burn them longer with better average thrust across the entire flight, reducing the total weight and fuel required to get to orbit.
well said @thebigitchy, but they do work with solid propellants, at 9:15 of the video I mention the NASA test of a solid fuel toroidal aerospike, they should work on any chemical fuel engine that currently run on bell nozzles.
Had this video been made just ten years ago then there would have been a lot of head scratching about why nobody had taken the aero spike engine development further. However the latter part of this video introduces the commercial component to rocket launching. If the cost of development of the aero spike engine cannot be recouped against the backdrop of reusable traditional bell housing rocket engines then they will remain a ‘what might have been technology’; making them part of the X33 SSTO program put too many eggs in one basket. The linear aero spike engine does have desirable attributes from an operational and manufacturing view point due to its being essentially modular. Small repetitive combustion chambers are ideal candidates for mass production. The overall engine thrust is scaleable by simply varying the number of chambers. Cutting ignition to individual chambers effectively throttles the entire engine allowing reduction in thrust at max Q and booster landing. In many ways the annular arrangement of multiple engines as envisaged for SpaceX’ BFR booster creates a virtual aero spike.
I think that's an important point - especially if you're recovering your stages, staging counters most of the argument for areospikes. Yes, they are more efficient at a variety of altitudes, but they are less efficient at any one altitude. So, if you're staging *anyway*, there's less need to use an areospike. You can build your stages so that the loss of efficiency is minimal, getting most of the effect of areospikes without switching to an untested technology.
Areospikes are brilliant for single-stage-to-orbit designs - but there's lots of reasons not to use those designs in the first place, which areospikes don't counter.
@ Daniel Staal
The aerospike is the optimal engine for the first stage where the atmospheric pressure drops fast but for space work vacuum optimized bell engines are better.
"Aye, that'll give 'er thrust!"
-- _Chicken Run_
Dan Black yes
Love that movie... :)
spoken by a true inventor
Got me to chuckle!
Thrrrruuuuusssst
Beautiful video. Very informative, thank you for sharing!
I’ve got to give you credit mate, you really know your stuff, and provide an entertaining view of these things.
Good Video dude. Your very good and explaining complex subject matter.
@joe santo there were a lot of holes....
They look like something straight out of a sci-fi film. I prefer the linear versions, they look awesome.
As someone studying maritime engineering, and being generally interested in science, I really love your videos. Keep it up :)
I very much wish to compliment you on the fine work that you do. Coming from a family whose dad was one of the early engineers in the early days of the space and missile programs for the United States, I very seldom see any presentations that are more than conjecture with little fact based. You are an outstanding representative of what a presentation should be, and have done your research quite well with the ability to throw out the gossip and rumor mail base facts and purely discuss and present the real scientific based evidence on every program you present
Most people do not know, but to prevent the 'Bell' nozzles from melting, the nozzles have thin pipes in them, and the liquid fuel is vaporized as it goes through causing a refrigerant effect before the gas is sent into the nozzle to be burnt for thrust. This is the main reason we do not have thrust vectored engines like on the F22 Raptor, yet, as the mechanics required for vectoring, cooling and safety is very complicated, heavy and very expensive.
As they always say, referring to rocket engines, 'there is a million ways for it to go wrong and one way for it to go right'.
2D only. Then how does Russia have 3d thrust vectoring on the more reliable and cheaper su-35 in service for years? Seems they have this figured out.
@@tnix80 Are you really comparing an after burner engine that is on for a few seconds to a Rocket engine that is massively hotter and on non stop?
The Saturn V had thrust vectoring on the first stages, with regenerative cooling of the upper bell. The four outer engines all had thrust vectoring and that was in the mid-60s
@@Cheradanine Saturn V had gimbling, not even remotely close to true thrust vectoring.
Great video ! Wanted to ask, would there be any advantages to using a combined bell/spike engine for reliability ? As I've no expertise I can only ask . Keep up the great videos .
Exzellent Video, as always. I appreciate your Videos bringing up more questions as you answer some others. It makes me quite interrested in the field. Thanks, CD!
Wow. I'd forgotten all about the spike! Thanks for this great video!
I hope someday Aerospikes are used for at least booster stages of rockets, they're design is awesome and I believe that if they are proven, going for a typical bell shape instead of a spike will be a thing of the past.
Great video!
arca space is building a aerospike rocket
www.arcaspace.com/
In vacuum, the spike doesn't really do anything for you that a lighter, more easily-cooled nozzle doesn't. An aerospike is good for a _sustainer_ stage like Atlas I's centre engine, though, or a single stage like VentureStar.
Quinsey Fritz No, no, no, the Aerospike should be used for upper stages and the bell nozzle used for the booster that gets the craft off the ground (sea level) till it reaches transonic speeds at high atlititude, then use aerospike enigines. That will make these engines practical application in the near future viable?
Corey Taylor. www.AdamtheWoo.com , has in his travels across the USA, explored an old factory that was trying to build these aerospike rocket engines.
Arca looks like total vaporware and seems pretty unlikely to ever fly.
Loved the presentation .... 👍👍
This is brilliant. I never thought to ask why the exhaust plume widens out when the rocket is much higher (I think I thought it was because of fuel running out in that stage, or because the old lower stage took a while to separate). But thanks to your wonderful explanation it explains it fully, clearly, and logically.
I had no idea about outside atmospheric pressure. What an informative video! Thank you.
Well done per usual
The main reason that we use multiple stages on rockets is weight, not engine performance. An empty fuel tank is just dead weight, so you can as well just drop it. Using multi stage rockets saves a ton of fuel and also reduces the size of these things significantly.
Deus EXmachiA I think the other part of why staging is used is because the engine attached to the empty fuel tank has a significant mass as well.
If the engine wastes less fuel on an inefficient nozzle design, that might mean the rocket needs less fuel to go to the same altitude. That probably lowers the size and weight of the fuel tank, reducing the need to drop separate stages.
In old Soviet books on rockets I saw an interesting design where the rocket worked as a syringe. As it burned it got shorter and shorter and the excess tank walls just got burned or gradually dropped. This could be the next evolutionary step because it allows to go from a number of discrete stages to a continuous single stage. It also saves on engine weight.
Now add to this a variable shape nozzle and you got yourself an ideal chemical rocket.
+Ivan Bulanov
That sounds fantastic in both senses of the word.
It sounds like it could be amazing if done right...
...but it also sounds like a fantasy concept that would be impossible to implement.
I mean, if someone does find a way to make it work? Great! But I'm unconvinced that it can be done.
Again very well done. Your explanation is not only correct but moreover easy to understand by layman. You are also exactly correct in your assessment of why the aerospike engines havent caught on. I would recommend your videos to any college aerospace engineering students
Excellent presentation. Very informative. Thanks!
The linear aero spike engine seems so like the next step that should be taken.
Damn the cost! Nasa needs to bring back the Venture Star program, re-vamped, with Space X as a partner. We need a shuttle replacement that works well!!
That was NASA's big mistake
That should be the title of your video : "Nasa's Big Mistake" Or maybe a Future Video??
I even built a hybrid electric/rocket plane, and called it "Future Star".
here is a link:
ua-cam.com/video/J7f8hf8kgfg/v-deo.html
the space shuttle design is retardedly complicated compare to the design of the BFR. Plus NASA does not get the infinite cold war funding it had. The tech space x uses was already available but NASA does not have the capability to exploit it due to its retarded structure. Space x also has few competitor on the same level because of the Business mentality of "if it works, it's good enough".
SSTO like in science fiction wont happen until we make powerful and efficient energy sources and extremely efficient engines. Yet most of the planet is still fucking around with combustion engines and wind or inefficient solar energy like solar pannels
I saw the partially assembled X-33 in its abandoned hanger back in 2004. Crazy to see such a high tech machine abandoned and covered in owl shit. Making the fuel tanks in the shape necessary for that lifting body platform is just too complicated, and materials haven't changed much since then. It'd be interesting to see a conventional cylindrical rocket using them though.
Nope, NASA dodged a bullet.
First, the contract that NASA had with LockMart was a "prove it' contract, they got a fixed one billion dollar contract, if they exceeded that amount, LockMart had to eat it. They exceeded the billion dollars, LockMart had the nerve to ask NASA for more money and NASA said "Did you read the contract you signed?" By that time, LockMart wasn't going to do so and they stopped all work on the X-33, then a year later tried to hand it off to the USAF and they got laughed at. Why? Because...
Second, the X-33 was attempting to use technologies that had never been used for spacecraft, including composite laminate fuel tanks to save weight; and here's when things got ugly; during a tanking test of the X-33, when they were refilling the tanks with liquid nitrogen, one of the two tanks proceeded to split like an overcooked hot dog. This caused LockMart to consider adding metal fuel tanks to replace the composite laminate, which led to the issue that killed it.
Adding metal fuel tanks increased the weight of the X-33 to where it could not launch from the pad, it would have been too heavy-and that's when LockMart went to NASA and started begging, with NASA telling them to stick it and the USAF running away as fast as they could. And mind you, the X-33 was a quarter scale prototype, not a full scale one.
Don't blame NASA, blame LockMart.
These videos are getting really professional!
Absolutely fascinating- thank you!
Also ditching fuel tank weight as they empty kinda encourages multi-stage designs anyway. That reduces the range of altitudes an engine needs to work over.
Steven Clark That's a good point. Until this video, I'd thought it was dropping the empty weight, and making landing/recovery easier, that were the main reasons for multi-stage heavy lifters.
Steven Clark This is true, but dropping pieces of the rocket into the ocean means the rocket has to be rebuilt if used again. If the rocket is one piece and can be landed safely all you have to do is refuel it.
syaondri That sounds like it would work, although it would probably complicate other things.
_Sounds_ _Like_ _It_ _Would_ _Work:_ The USAF and USN have used detachable external fuel tanks on their fighters for decades. Even better, there's a certain type that bolts onto the airframe directly, called "conformal fuel tanks" because they're not the more traditional cigar-shaped pod hanging off the underside. My understanding is these CFT's are the best bet for extending a fighter's range, because not only do they let it carry more fuel, but they don't cause a lot of extra drag the way a more standard external tank does.
_Would_ _Probably_ _Complicate_ _Other_ _Things:_ The disadvantage of CFT's is they can't be dropped to shed weight and improve the plane's aerodynamics. Once they're on, they're on until the ground crew disconnects them. The reason is, the tanks are wired into the plane's fuel system, rather than keeping the internal fuel tank topped off like external fuel pods do. I'd imagine trying to shear off something that long and close to the fuselage - the CFT's on the F-15 are something like 20 feet long - would make flying really tricky, too, but that's mostly speculation. Either way, it would change the plane's balance and handling very suddenly, and rockets' failure rates are scary enough without adding more things that could suddenly decide to go squirrelly.
_Why_ _Consider_ _CFT's_ _At_ _All,_ _Then?_ Because big external tanks impose a _lot_ of extra drag. That means you need a bigger engine to toss the whole contraption into space, which means you need _more_ fuel, which means an *even* *bigger* engine, which means... And so on. Tsiolkovsy's rocket equation isn't complicated, as rocket science goes, but it is absolutely merciless.
All that said, I would not be surprised at all to learn that a group like SpaceX is working out the math so they can add extra fuel tanks that A) aren't also the engines themselves, like the STS and multi-stage rockets use, B) conform to the main rocket body such that they don't add horrible amounts of extra drag, and C) can be safely shed once they're empty. It's an engineering challenge, and rocket scientists are pretty good at that kind of thing. Here's hoping!
Internally-stored, ejectable fuel tanks? I had not thought of that, that's clever! Ditching the empties would change the center of gravity, but then, so does dropping the large external tanks, booster rockets, and empty stages currently in use, so that would happen either way. Yeah, the more I think of it, the more I like that idea.
And space guns! An engineer by the name of Gerald Bull was working on the idea of shooting payloads into orbit in the 1970's/80's, until the Israelis decided his practice of building cruise missiles and gigantic cannons for the Iraqi Hussein regime probably wasn't going to end well, and had him whacked. (...Well, we don't _know_ it was the Israelis: they certainly had a motive to bump off a weapons designer in Saddam's employ, but so did a lot of other people, like the Syrians, Iranians, South Africans, CIA, MI6, and a bunch of others. I guess building weapons is a dangerous job, for some reason.)
At the time, the big problem with Dr. Bull's design was that the shock of firing would be immediately lethal for any astronauts. A railgun's ability to spread the acceleration out beyond the immediate impulse seems like it could solve that, if you made the launch facility long enough.
And, of course, an orbital elevator would solve all these problems to the point of triviality. We just need to find or make something strong enough to reach that far under tension.
Would love to see one by you folks on asteroid prospecting and harvesting/mining.
Read the book The Moon Is A Harsh Mistress - Robert Heinlein. The Earth sits at the bottom of an 11 Km/s gravity well. the ultimate weapon system is being able to throw stones into it. An asteroid with very high metal content, measuring around 30 - 50 meters in diameter would hit the ground releasing the energy of a 20 megaton nuclear warhead, without radiation. A big stone in space shoved correctly on purpose, or by accident, could take out a city of millions years later. Who'd know who done it, or when it was pushed? We've seen space experts drop the ball and kill astronauts. We don't need these so called experts pushing stones around space and putting us all at risk. Especially responsibility shirking mining / drilling / energy corporations who's only interest is making money and pleasing shareholders. Who's going to set the rules, what nations will abide by them? who's going to make sure the rules are enforced? just how do you enforce them? who decides who can and who cannot mine, and who owns what asteroid? how do you claim an asteroid as yours? this is the stuff that starts wars.
@@climatechangefanclub7100 All those questions will get answered as they are faced by mankind. Asteroid mining is the financial incentive needed to turn humanity into a space-faring species.
Extraordinary video once again! Thank you!
Thanks for sharing this information. Now I know why they used the three stages from the Saturnus rocket.
Thanks for the clear explanation. Superb.
Great vid. Really interesting.
Not lack of financing misappropriation of funds.
so this is rocket science
I'm not surprised if I don't understand
Great vid, well explained and a pleasure to watch
Brilliant presentation, well written and presented in a way that a layman can understand. Very educational.
I loved your video Curious Droid :)
This guy is great, education in such an entertaining way
He should cover statistics, calculus and topology.
Amazing. I took notes and understood tonnes of rocket science.
Amazing presentation! Love rockets and everything related.
Just a quick correction regarding 2:27: 1in² equals 6.45cm² (2.54² cm²).
2.54 centi-metres, 50 kilo-metres PLEASE! There is NO decimal prefix called a "ki-lom" and there is NO unit of length called an "etre"
How many decibels in a bushel again?
I wish I knew math lol
Watching this to prepare for everyday astronaut's vid coming soon lol, great video
Same here.
thank you for the good explanation of aerospike engine
Thank you for your videos are very informational and I thoroughly enjoyed them
Its 4 am and am watching this.. One of yur most interesting videos for me so far... Love em .keep it up
The SSTO concept had me searching for a Skylon episode - and there wasn't one... If you're ever short of an episode idea, that would be fascinating.
Vqr5David Murphy kq
Beautifully presented!!
Great Video... I used to track the X33 program a long while ago, and always hoped the Aerospike engine technology would have lasted and been reused. Too bad it didn't make it (yet) into a new funded program. Thanks for the article as it explains the "why".
When someone says 'It's not rocket science' in aerodynamics 101, and everyone gives them the death stare.
WHOOOSH!
but it is not rocket science....
We stage mainly because of the mass ratio. Staging reduces the required mass ratio to achieve orbit to something that is buildable with our current materials. Therefore, though the bell is less efficient, it is good enough. Additionally the dual bell, which is almost as good as an aero spike, is preferable for an SSTO as it is easier to build and better understood.
Hopefully SABREs will be an option within the next decade as well.
According to Reaction Engines, "the SABRE will fly in 5 years."
They said this just last year, 2017.
.
They also said this, verbatim, in 2011
.
They also said this, with same meaning slightly different phrasing, in 1982
(they were also named differently then, but same people, same concept)
Great presentation, open one's mind to different possibilities, Thank you!
enjoyed this a lot, thank you!
Hidden until now, original voice recording from the launch of the Enterprise NCC-1701 as it reached the outer layer of the atmosphere:
"Cap'n, she's breakin oop. We're loosin thrust man."
"There's no time to lose Scotty. Engage the Aerospike"
1980s = new technology...
Who would have thought that the space industry was the most outdated..
It's not lol, it's just under cover while the rest of us worry about a fake virus.
@@SuperDirtPig
You deserved a like for being woke
Excellent Video Explanation !!!
Thank you for explaining gravitational force, I was just wondering about this same thing 2 days ago.
Everyday astronaut is talking all the time about his upcoming video about this and now this one gets recommended
daniel_960_ It’s really odd , i only clicked on this video because of his mention about aero spike engines during the new Starship presentation
Damn!!! That shirt is louder then a rocket engine.
Well presented and explained
Amazing, now I know a little bit more!