|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
Atomic ramjet for exploring Titan
On Mar 18, 7:32 am, "Greg D. Moore \(Strider\)"
wrote: "Frogwatch" wrote in message ... In the late 50s and early 60s, the USA had "Project Pluto" a nuclear reactor powered ramjet whereby a reactor directly heated incoming air to provide thrust. It could be capable of flying for months but emitted a lot of radiation, maybe even a lethal dose to anything nearby. So, say we want to explore Titan completely from the air, we drop a Pluto style ramjet into the atmosphere of Titan where it flies around for months sending back data. At the end of its life, we could simply allow it to crash OR we could use onboard solid rockets to accelerate it to escape velocity from Titan and allow it to either go in orbit about Saturn or to drop into Saturns atmosphere. Such a flying machine might be just what we need to explore Venus too. The dense atmosphere would allow for fairly low speed flight there. I'm honestly trying to figure out if this is the most absurd idea I've heard in awhile, or absolutely brilliant. I suspect a bit of both. -- Greg Moore Ask me about lily, an RPI based CMC. I suppose you could use the reactor to heat air to drive a Sterling cycle engine to turn props but this is mechanically more complicated than the ramjet. Neutrons are emitted regardless of whether if it is a ramjet or prop driven. Pluto was tested on the ground in NV. Wings are well known so how much testing do we need? |
#12
|
|||
|
|||
Atomic ramjet for exploring Titan
This is a good idea - made even better by the fact that there is no
oxygen to ruin things in the Titan atmosphere. Also the temperatures need not be as high as for Earth. That's because ambient temps are higher and gravity is lower. A counter-rotating prop - powered by an electric motor - supplied with energy from a compact high temp nuclear reactor - using thermophotovoltaic stack around a nuclear filament - would be ideal. We'd get about 10 kW/kg of weight - so the nuclear lightbulb generator would mass about 3.7 kg - and be capable of lifting 300 kg or more - more weight than the Cypher in Titan's reduced atmosphere - and denser atmosphere. A mirv like bus would aerobrake into Titan orbit, and release an orbiting communications satellite into a stable orbit. The bus would then descend and aerobrake to a landing on Titan's surface, but not before releasing two or three Cypher like nuclear aerial vehicles. The aerosheild would descend to the surface and have the ability to transmit data and images back to the hovering vehicles, which would then communicate to the orbiting comsat which sends data back to Earth and recieves commands from Earth. Something like this; http://en.wikipedia.org/wiki/Sikorsky_Cypher General characteristics * Crew: None * Capacity: 50 lb (23 kg) * Length: 6 ft 2 in (1.88 m) * Rotor diameter: 4 ft 0 in (1.22 m) * Height: 2 ft 0 in (0.61 m) * Disc area: 25.2 ft² (2.4 m²) * Loaded weight: 264 lb (120 kg) * Max takeoff weight: 300-340 lb (136-154 kg) * Powerplant: 1× UAV Engines AR801 Wankel rotary engine, 50 hp (37 kW) Performance * Maximum speed: 52 knots (60 mph, 97 km/h) * Range: 49-67 nm (56-77 mi, 90-125 km) depending on model * Service ceiling: 8,000 ft (2,440 m) * Disc loading: 9.9 lb/ft² (47.5 kg/m²) * Power/mass: 0.2 hp/lb (0.32 kW/kg) * Endurance: 2-3 hours Avionics * EO, FLIR, small radars, chemical detectors and magnetometers, radio relay, and non-lethal payloads |
#13
|
|||
|
|||
Atomic ramjet for exploring Titan
Nuclear airplane and nuclear lightbulb (not gaseous core rocket, but a
nuclear core that operates in a vacuum like a lightbulb filament and radiates away most of its energy in the form in light) can be combined to create an electric airplane that is powered by a TPV stack around a small nuclear filament. This power plant has a wide range of uses - from ion rockets to driving fans for airplanes and helicopters on Mars, Titan, gas giants and so forth. |
#14
|
|||
|
|||
Atomic ramjet for exploring Titan
TPVs are capable of 30% and more -
http://www.appliancedesign.com/CDA/A...00f932a8c0____ Electric light bulb filaments are capable of 3,000K and more - http://hypertextbook.com/facts/1999/AlexanderEng.shtml Though not in the open literature, small self-heated nuclear filaments that self regulate (neutron cross section changes with temperature) and operate stably in a background - provide a means to create a tiny very powerful very long lived very robust power plant - that with a TPV stack turn into a very compact safe reliable etc., electrical energy source with very high power to weight - to drive all manner of electric engines. http://en.wikipedia.org/wiki/File:Bo...trator_AB1.JPG |
#15
|
|||
|
|||
Atomic ramjet for exploring Titan
The radiation need not spew anywhere - much of that was mis-reported
to make the ideas contained in the project seem outlandish. That was done to prevent folks from working on them when we decided not to. Fact is, we can build nuclear filaments as easily as we now build light bulb filaments and surround them with TPV stacks of tremendous efficiency to create very powerful very lightweight very clean power sources - to drive all manner of electric engines. The Navy is already working on a miniature nuclear sub and adapting this technology provides a means to power lots of different vehicles and appliances without any central power or fuel supply - for periods of decades or more. |
#16
|
|||
|
|||
Atomic ramjet for exploring Titan
On Mar 17, 2:14 pm, Frogwatch wrote:
So, say we want to explore Titan completely from the air, we drop a Pluto style ramjet into the atmosphere of Titan where it flies around for months sending back data. Just use a hydrogen balloon and you can stop and sample the surface. You may want a nuclear reactor along also, to crack the hydrogen from the atmosphere and provide craft power under all that haze. -HJC |
#17
|
|||
|
|||
Atomic ramjet for exploring Titan
Frogwatch wrote: So, say we want to explore Titan completely from the air, we drop a Pluto style ramjet into the atmosphere of Titan where it flies around for months sending back data. At the end of its life, we could simply allow it to crash OR we could use onboard solid rockets to accelerate it to escape velocity from Titan and allow it to either go in orbit about Saturn or to drop into Saturns atmosphere. You might run into a really unexpected problem with that...Titan has a very thick atmosphere, which could generate a lot of drag and heating on the ramjet if it tried to fly at multi-Mach velocities like SLAM/Pluto* was supposed to. On the other hand, Titan's high atmospheric density combined with its low gravity might make a propeller driven aircraft using a electric motor powered by a small reactor or RTG feasible. This could cruise along at quite a low velocity giving its sensors time to examine the surface under it. One other problem is that the atmosphere of Titan has a lot of turbulence in it according to the latest findings, so anything you fly around in it has to be pretty tough. Such a flying machine might be just what we need to explore Venus too. The dense atmosphere would allow for fairly low speed flight there. Can't get it too slow if you want a ramjet (nuclear or otherwise) to work...start-up speed for one is around 300 mph, at least in Earth's atmosphere. * _S_upersonic _L_ow _A_ltitude _M_issile...SLAM was the missile proper, Pluto was the code name for the project to develop it, TORY was the code name for the reactor-driven ramjet engine: http://www.designation-systems.net/dusrm/app4/slam.html Pat |
#18
|
|||
|
|||
Atomic ramjet for exploring Titan
Martha Adams wrote: I think that's an interesting idea and it sounds doable. However, is a ramjet really the best vehicle for this? A slower, propellor driven craft could feature less active and stressed machinery, better for a long life. And in either case, you'd want to do (in my view) at least three proof-of-principle machines to test out the engineering: where would you fly those machines? We must understand how it flies in a cold dense methane atmosphe First we rent a wind tunnel. Then we put huge air conditioner at the front end of the wind tunnel. Then we put 1,000 cows inside of a building that's air output is fed into the air conditioner's intake. Then we feed the cows nothing but beans and wait for the Wonders Of Biology to begin. For testing the Venus one, we simply reverse the air conditioner's heat exchanger, attach sparklers to the rear end of all the cows, and feed them beans along with rotten eggs - creating a superheated carbon dioxide and monoxide rich atmosphere including exotic sulfur compounds. ;-) Pat |
#19
|
|||
|
|||
Atomic ramjet for exploring Titan
Matt wrote: Project Pluto was dropped because, among other reasons, there was no safe way to test the thing under actual flight conditions. Likewise, you could not test this engine until it was well out in space, and what if it didn't work? They did test the TORY engine out on the ground, and it did work as advertised. There's a Discovery Wings episode about it, and when they show the view up the back end of the reactor as it goes critical and starts glowing yellow-white hot as the air is blown through it (the air was stored under high pressure in a huge array of high-strentgh steel pipes) it's really something to see. They photographed it by having the camera on the far side of a radiation-proof wall and aimed at a mirror that faced the exit nozzle of the engine. If they did get around to tests, plans were to have the missile fly around out over the ocean, and either crash into the ocean at the end of the mission, or dive into a lake some ways inland for retrival. You've shot your program budget. In any event, emitting radiation into the atmosphere of another body is bound to raise a storm of protest. Titanic Titanian Methane Muskies are bad enough...exposure to radiation could create Terrifiying Titanic Titanian Mutant Methane Muskies, and that's the last thing our solar system needs. Pat |
#20
|
|||
|
|||
Atomic ramjet for exploring Titan
Frogwatch wrote: I suppose you could use the reactor to heat air to drive a Sterling cycle engine to turn props but this is mechanically more complicated than the ramjet. Neutrons are emitted regardless of whether if it is a ramjet or prop driven. Use a RTG, and you can seal the isotopes in ceramic and just use their heat to drive some sort of power generator. With its high atmospheric density and low gravity, Titan is the place where you could literally float safely down to the ground under a umbrella like in a cartoon, so the wings need not be very big in comparison to the weight they can carry. Pat |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Mystery space ramjet booster looking thing. Any ideas? | Scott Ferrin | History | 24 | November 16th 07 12:48 AM |
Mystery space ramjet booster looking thing. Any ideas? | [email protected] | History | 0 | November 14th 07 11:19 PM |
ramjet/scramjet: what makes expanded gas to go out in the back not the front? | peter | Technology | 16 | January 20th 05 02:16 PM |
APR Extras: Little Joe 2-LEM, Ejector Ramjet X-15 | Scott Lowther | History | 6 | December 13th 04 07:39 AM |
APR Extras: Little Joe 2-LEM, Ejector Ramjet X-15 | Scott Lowther | Policy | 0 | December 12th 04 10:33 PM |