In the 70's a west german company (also called OTRAG) created a design for a rocket that was basically a bunch of small, mass produced and cheep, that could be increased to the size needed for any launch by gust adding more of these Rockets. Now the company failed but it seems like it failed more because its launch site was in the notoriously (un)stable country of zaire, and that more or less killed the project. One thing I intresed in is could this idea (of mass produced rocket engines that are inarintly disposable) have worked, preferably in a better country like idountknow Brazil maby?
Could the OTRAG idea work
- Thread starter cjc
- Start date
I'd see a nuclear-armed apartheid South Africa as the most likely supporter of a viable OTRAG. That bomb of theirs would have needed a delivery system, after all.
IOTL, IIRC, the OTRAG boys approached Muammar Gaddafi, which did not go down well at all in western capitals. Apartheid SA would have been a safer bet on that grounds, at least until the reality of what they were dealing with became clear.
IOTL, IIRC, the OTRAG boys approached Muammar Gaddafi, which did not go down well at all in western capitals. Apartheid SA would have been a safer bet on that grounds, at least until the reality of what they were dealing with became clear.
No, its a horrible idea from an engineering standpoint in that it exponentially increases the number of failure points. And rocket engines are already disposable.
In general you want as few engines as possible for any rocket design.
Model Rockets
what-if.xkcd.com
For reliability yes (presuming no engine out capability) but for cost having smaller cheaper engines might well be better especially if the engines are also used in other systems?
I think the best bet is simply get somebody other than Libya, preferably somebody with more international stability and support?
Would the single tubes also not make perfectly good battlefield rockets for some mid-rate power as they use storable propellants, if they are used in large numbers then the cost of space use, might be far lower? What sort of payload and range would a single tube give?
IIRC all the engineering was done in Germany, Zaire was just a place willing to completely overlook range safety issues. After the whole Zaire and Libya debacle they actually did some testing at a range in Sweden which failed badly. OTRAG’s idea seemed to be along the lines of “what if we did rocket science without all those pesky aeronautical engineering rules and just did whatever was cheap and looks like it might work?”.
Conceptually valid and interesting but it didn’t seem to work out in practice.
http://www.svengrahn.pp.se/histind/Swefirst/Soundingrocketdetails/OTRAG/OTRAGEsrange.htm
The thing I reacted to most was the German failure report apparently citing launch vehicle acceleration at 9.9G rather than the predicted 7.3G. Rockets are not really my thing but that seems to me like a pretty massive error to be making and hints at a sort of “suck it and see” approach that I don’t associate with success in high-performance engineering.
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No, with rockets you want to make it as simple yet robust as possible. It's not like a multi-engined plane, where one engine failing just means a different power to drag ratio. With rockets one failure = kaboom. Far better to only have to inspect 1-4 big engines than a dozen or so little ones.
Can you mount a gun-type nuke on a missile?
RamscoopRaider
Donor
Yes you can, depending on the definition of missiles and gun type nuke, the former can range from a Stinger to an SS-20, the latter from a 105mm shell to Little Boy. That said there is every indication that South Africa's weapons were far in excess of 200 kilograms and it was not practical for them to go on an RSA series missile
Err... No. Saturn V and Falcon 9 have both had engines fail on the way to orbit, and still got their payload to orbit.
Once you can properly deal with engine out issues, the more the better, in some ways.
With OTRAGs simple pressure feed engines what would be the likely failure modes, would they just lose thrust or would they explode? And inspection wise do you really inspect such simple engines them post factory or just build them and fuel then fly them?
from wiki
Is this not the easiest way to get them to work have Sweden want to take over? Sweden can want it for unofficial duel use and since it has a large industry Saab and Bofors etc with the skills to get it to work, they are also unlikely to be stopped by outside powers as they are neutral and less threatening and more powerful so less easy to persuaded them to stop?
Seems pretty unlikely TBH. Sweden had both solid and liquid-fuelled missiles in service use before OTRAG became a thing so if they wanted nuclear launch vehicles they seem more likely to leverage their own technology than take over a flamboyant German chancers idea of super-low-cost civilian payload-flinger.
In the early eighties I don’t think nitric acid and kerosene was super attractive for a theatre ballistic missile but as I said rockets are even more outside my area of expertise than most things.