General Electric HTRE-3 Nuclear Jet Engine

https://planehistoria.com/general-electric-htre-3-nuclear-jet-engine/

by bane • 2 years ago

82 70 2 years ago

JKCalhoun• 2 years ago

Such a wild concept from a wild time in history.

I have wanted upon occasion to put together a YouTube channel where I drop in on nerdy road trip destinations to try and get others to roll out and check these places out as well. I think in fact it was my stumbling upon the Experimental Breeder Reactor 1 [1] where I first hatched the idea.

Such an amazing place and with those crazy nuclear jet engines just sitting outside.... So sublime: a picnic lunch with the wife and kids at a table by the experimental nuclear engines....

[1] https://en.wikipedia.org/wiki/Experimental_Breeder_Reactor_I

sneak• 2 years ago

I wonder if a RTG could produce enough to run an electric quad or optocopter?

For certain applications if unmanned you wouldn’t really need to worry about shielding. I wonder how long those motors can run continuously?

alejohausner• 2 years ago

The RTGs on the Voyager spacecraft weigh 38kg. They initially produced 160 Watts. That sounds like a no-go to me.

FredPret• 2 years ago

It might not have great power density but boy does that thing keep going for decades

Gibbon12• 2 years ago

I think you need 1 hp per 10-15 lbs of weight to fly. I think that's around 130 W/kg. I checked a piper cub is something like 100.

Other hand Pu-238 produces 570 W/kg. A piper cub with it's 48kw engine would need 87kg of Pu-238 to produce the same energy.

I looked up the cost, $1968/g. So 48kw would cost $171 million.

Interesting idea but doubt.

brnt2• 2 years ago

I wish Toshiba would have actually sold that RTG laptop battery. Imagine never having to charge!

hypercube33• 2 years ago

Not just Voyager but the mars robots as well.

beefman• 2 years ago

Dragonfly is NASA's RTG-powered octocopter. It launches for Titan in 2028

https://dragonfly.jhuapl.edu/

https://en.wikipedia.org/wiki/Dragonfly_(Titan_space_probe)

doctor_eval• 2 years ago

I got nerd sniped by this and asked GPT some questions.

Given a 45kg RTG plus the weight of the drone itself, you’d need to be able to lift, say, 60kg.

Energy required to hover 60kg using a 4-rotor drone at 70% efficiency is about 10kW - according to GPT. I don’t know enough to say if this is true or not.

Assuming it’s correct, and that a 45kg RTG generates about 300 watts, give or take, the answer is:

no.

namibj• 2 years ago

There is no technical minimum; the only thing to keep in mind is that lift/drag ratio relates potential energy (moving mass up against gravity) to travel distance. This applies independent of speed and vehicle type (even running counts!).

mr_toad• 2 years ago

Nuclear Stirling engines can run for a decade or more, but are still too heavy for a helicopter.

riffic• 2 years ago

Did they just expect these aircraft to never crash?

SoftTalker• 2 years ago

No, that was one of the practical problems with the concept.

kristopolous• 2 years ago

As far as I can tell, aircraft and space nuclear propulsion still hasn't actually be used in flight, right?

colechristensen3• 2 years ago

Correct depending on if you count spacecraft with electric propulsion powered by radioisotope generators.

topspin• 2 years ago

Reactors have been flown and made critical in flight, but never used to provide power for aircraft propulsion. The Soviets got the closest, but they abandoned it as well.

Recently Putin has revived a nuclear powered cruise missile design. Status is unknown publicly, but it is believed to have been set back by a major test failure and contamination event.

Today, one can imagine solving the crew shielding problem of these large, nuclear powered bomber concepts by simply eliminating the crew and foregoing most of the requisite shielding. Had that been possible at the time these concepts might have been deployed.

acidburnNSA2• 2 years ago

Correct. Snap-10A was a nuclear fission powered satellite. It was not propulsion.

kolinko• 2 years ago

Not in flight, but Nerva had multiple prototypes built and tested - the longest run being over an hour long. It was cancelled due to politics, not technical viability.

https://en.wikipedia.org/wiki/NERVA

jaggederest5• 2 years ago

Here's another fun one:

https://en.wikipedia.org/wiki/Supersonic_Low_Altitude_Missil...

An unmanned nuclear-powered ramjet designed to spew warheads, with a predicted range of 116,000 kilometers.

colechristensen3• 2 years ago

And for scale that’s circling the earth three times.

viraptor• 2 years ago

Well, that's the best setup for the roadrunner ACME missile launcher joke I've ever heard.

jesperwe• 2 years ago

...at ground level.

slow_typist• 2 years ago

We were lucky, and got ICBMs instead.

boxed2• 2 years ago

The problem with it was that they realized they didn't even need the warheads, they could just switch the plane to an open cycle reactor over enemy territory, spewing endless radioactivity and making the entire Soviet Union a nuclear death zone for thousands of years.

That's also why it was classified I believe. No one wanted the Soviets to get the same idea.

gambiting• 2 years ago

As someone else already said - there wasn't really any risk of that, the reactor wasn't "shedding" enough radioactive material or even emitting enough radioactivity to be a danger to anyone standing on the ground. Maybe if you made it fly in a loop around one place it would start to add up, but it wouldn't be anywhere on the scale of "making the entire soviet union a nuclear death zone" - you'd need thousands and thousands of these flying across their entire landmass 24/7 for weeks if not months, which

1) is just a stupid idea

2) if you have the capability to do this, you also have the capability to detonate actual nukes which can be tuned to produce maximum amount of fallout if that's your goal.

worstspotgain3• 2 years ago

I see your GE HTRE-3 and raise you a https://en.wikipedia.org/wiki/Ford_Nucleon

acidburnNSA2• 2 years ago

This was never serious. Technical writing e.g. in textbooks in the 1950s explain that a nuclear-power car is 'not within the bounds of reality'.

https://babel.hathitrust.org/cgi/pt?id=mdp.39015003994194&vi...

creshal• 2 years ago

Today, we have nuclear powered cars on Mars.

And with their amazingly powerful (checks notes) 0.13hp engine, you'll have plenty of time to admire the view.

worstspotgain3• 2 years ago

Hmm, I don't know, it's a concept car, not a sci-fi car. Show me a big shot realist and I'll show you an even bigger dreamer.

torrefatto• 2 years ago

I guess the author gets paid by word count. The piece could have been written in one third of the length.

Toutouxc• 2 years ago

I see you’re getting downvoted, but that was my first, second and third thought when reading the article. It’s suspiciously hand-wavy about the technical details, things are repeated several times and it really does feel like the writer was trying to stretch the article with the help of a LLM.

AlphaGeekZulu4• 2 years ago

The piece was definitely written by an AI.

And a bad one at that. It is a redundancy nightmare.

To save your time:

"In 1951, the United States military initiated a program aimed at developing a nuclear-powered aircraft capable of unlimited range (ANP program).

The program’s goal was to create a nuclear reactor small enough to fit into an aircraft yet powerful enough to provide the necessary thrust while ensuring the safety of the crew from radiation.

General Electric (GE) initiated the HTRE (Heat Transfer Reactor Experiment) series to create and refine the technology necessary for integrating a nuclear reactor with a jet engine.

The reactor in the HTRE-1 was essentially a modified version of existing nuclear technology adapted for aviation use.

The HTRE-2 tested different configurations and setups to optimize the efficiency of the nuclear jet engine concept.

The HTRE-3 featured a more compact and efficient reactor design that was closer to what would be needed for actual aircraft implementation. The HTRE-3 incorporated a modified General Electric J47 turbojet engine, which was a well-known engine in military aircraft at that time. The HTRE-3’s design was sophisticated, involving a direct cycle in which the air passed directly through the reactor core, getting heated in the process and then expelled to generate thrust. Moreover, the HTRE-3 featured improved radiation shielding techniques

While the HTRE series ultimately did not result in operational nuclear-powered aircraft due to various strategic, technical, and ethical considerations, it significantly advanced the understanding of nuclear propulsion."

b112• 2 years ago

We've come a long way in material construction in the last 50 years, I wonder if this could now be built.

cabirum2• 2 years ago

Summarize using AI?

hubraumhugo• 2 years ago

Sitting here with my morning coffee and reading about a nuclear jet engine I've never heard of makes me realize how special HN is. Please, never change!

Harmohit• 2 years ago

They have also tried to use nuclear power for space propulsion. Here is a fun one: https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...

User23• 2 years ago

Neal Stephenson put this to good work in his novel Anathem.

hagbard_c• 2 years ago

And, much earlier, Larry Niven and Jerry Pournelle in Footfall.

cubefox• 2 years ago

This is not just a curiosity though. Nuclear pulse propulsion like Orion is actually the most advanced form of space propulsion that is within technical reach and doesn't use science fiction ingredients like large amounts of antimatter. When you read the article, you see that Orion was considered quite doable even decades ago. There actually is one system that would be even more efficient than Orion, the Medusa:

https://en.wikipedia.org/wiki/Nuclear_pulse_propulsion#Medus...

Though the Medusa design is less fleshed out than Orion.

zidad• 2 years ago

Sounds like a keeper. I don't see what could possibly go wrong with deploying these at scale everywhere.

pfdietz• 2 years ago

We could see nuclear aircraft engines deployed on Titan. They would work great there.

cabirum2• 2 years ago

This one didn't get cancelled https://en.m.wikipedia.org/wiki/9M730_Burevestnik

rthnbgrredf• 2 years ago

Does someone know how long an unmanned unclear powered aircraft could fly?

General Electric HTRE-3 Nuclear Jet Engine

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