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By: - 11th May 2001 at 06:52 Permalink - Edited 1st January 1970 at 01:00
RE: Airborne Nuclear Reactors........
The major problem was weight. The powerplant alone weighed tens of thousands of pounds. The lead shielding to protect the crew and avionics was another source of considerable weight. Just doesn't make it practical for an aircraft.
By: - 11th May 2001 at 07:21 Permalink - Edited 1st January 1970 at 01:00
RE: Airborne Nuclear Reactors........
Water, in large quantities is also pretty heavy but I suppose it would be ofset by not needing to carry much fuel...
By: - 13th May 2001 at 09:38 Permalink - Edited 1st January 1970 at 01:00
RE: Airborne Nuclear Reactors........
the generator makes pressurised steam, this can be used to drive a turbine/s thus, cutting out the middle generator man, and operating the drive shaft for the engine-pity this thing can't be made light enough!!!!!!! I just say give it time-read new scientist, for a story on an elevator which will take you into space!!!!!!!!
coanda:7
By: - 13th May 2001 at 15:07 Permalink - Edited 1st January 1970 at 01:00
RE: Soviet Airborne Nuclear Reactors........
Not only the Americans tried it with the NB-36H (initially) and later X-6A (the very same aircraft after some additional modifications) but so did the Soviets with their Tu-95LAL, which was intended to preceed a production version called Tu-119. Propulsion was the NK-14A engine, which was driven by the reactor's turbine. These two engines would take care of cruise flight, whereas two regular NK-12 engines on the outboard stations would only be ran during takeoff and other power-intensive parts of the flight envelope.
Tu-95M 0408 was the lucky one to be modified in the late 1950s. After a whole lot of shielding and flightworthy tests with weights, the reactor was fitted at Semipalatinsk in May 1961. Until August of that year a number of flights were made, including a few with a 'hot' reactor. I haven't found any confirmation if it actually propelled the aircraft though (which definately never happened with the NB-36H/X-6). In the end, the aircraft was shelved because of the huge costs involved. It was later reconsidered for the Tu-142 but again cancelled for the same reason. The Tu-95LAL was then used as an instructional airframe at Semipalatinsk, and scrapped in the early 1990s.
As for the X-6, i don't have much on it but i guess a websearch will do wonders.
Regards,
Arthur
By: - 14th May 2001 at 00:37 Permalink - Edited 1st January 1970 at 01:00
RE: Soviet Airborne Nuclear Reactors........
humm....i've always thought that the nuclear reactor was used to heat up a closed cycle liquid coolant (most likley liquid metals) that then pass the heat through the heat exchanger that acts as the combustor of the gas turbine. Powered by steam drives?...that would be contradictory to the jet engine and would be very very inefficient. I've seen a diagram of the B-36 version, so maybe the Russian engine is different. If any have diagrams or schematics of the system, thought would be extremely helpful..
By: - 14th May 2001 at 10:52 Permalink - Edited 1st January 1970 at 01:00
RE: Soviet Airborne Nuclear Reactors........
whilst being stupidly heavy from a safety point of view, that seems like the worst!!! although I'm sure it would work in principle, I think the chemistry in this is too hard to perfect, unless someone knows how its done????? we certainly didn't cover it in any of our physics classes!!
coanda:7
By: - 14th May 2001 at 10:55 Permalink - Edited 1st January 1970 at 01:00
RE: Soviet Airborne Nuclear Reactors........
I think that steam TURBINES would be the most efficient of the lot actually, the loss of water is basically zero, and the pressure is provided easily enough, and with a reactor that can run on very very little material, it is the most efficient, or else they would use steam turbines in power stations would they?????
By: - 14th May 2001 at 23:19 Permalink - Edited 1st January 1970 at 01:00
RE: Soviet Airborne Nuclear Reactors........
uh...unless someone can disagree, liquid metal is used so the operating temperature is much higher, but, just like water, it's operating at the phase change conditions of vapor and liquid. Why not steam?...even at elevated pressure, water doesn't have enough heat capacity per unit mass to carry the high heat flux required by the combustor unit of a jet turbine engine. When you say using a steam turbine, i assume that the turbine drives the compressor directly and there's no recuperating turbine that continues on the compression....but you've forgot that a turbine engine don't just compress air and then ejected it at a higher velocity. Yes, that'll have some thrust, but the bulk of the thrust comes form adding heat in the combustor at very high pressure ratios, which significantly increases your efficiency. In other words, the discription you gave is very similar to a WWII Italian design, driving the compressor with a IC engine, but the efficiency is very low because the designer still have to inject heat into the compressed flow. Maybe you're correct since i have no details of the Russian design, but i'm 90% sure this is how it work in the proposed American design where reactor heat was dumped into a specialized combustor that is actually an advanced high efficiency heat exchanger (minus the "liquid metal" part that's my take...that's purely from the fact that if steam is used, the efficiency will be very very low).
By: - 15th May 2001 at 18:55 Permalink - Edited 1st January 1970 at 01:00
RE: Soviet Airborne Nuclear Reactors........
ok in a closed system, such as that in a steam turbine, then it would be efficient because nothing is lost, correct liquid metal is going to have a higher energy capacity per unit weight, thats true, and it would be even better under high pressure, this may well be capable, and I'd like to know more about if anyone can help, but from what I know, steam is used because of its low reactivity with metals, its easiness of handling, and its ability to hold enrgy, and be manipulated safely. Metals have only the ability to hold energy, and that is its main advantage, I believe thats why they use it in power stations, in smaller applications liquid metal is going to be practical-maybe thats where my thinking is letting me down!! anyway, it is efficient enought to drive a generator, when the steam is put under pressure, since when it is let into the turbine, it is at speed, and thus turns the turbine. from what I know, in power stations turbines can have upto 6 sets of compressor blades-more info on this would be helpful, where can I find out about that engine??????
coanda:7
Posts: 465
By: Paul Cushion - 10th May 2001 at 23:42
Ages ago, I read an article about the use of Nuclear reactors to power aircraft and a reactor was in fact carried by a Convair B-36 in the 1950's although it did'nt power the engines.
How would this in theory work? How would it turn an engine? Could it really be done? I am aware that it's not a practical way to power aircraft but nevertheless an interesting subject......
Paul.