Talk-Polywell.org

Keegan wrote:I thought site was meant to be a bastion of serious fusion related scientific discussion.

Polywell aircraft ? We have both worked in Aerospace and Simon you have got to be kidding me :) Im with you on the miniscule amount of fuel required, but the size and aerodynamics of the reactor space, the cooling sytems, the power supplies, the electric engines, the wieght, the complexity all scream to me "Engineering Abortion"

I hope the USAF succeeds in "growing" their own fuel. I know they have a few programs running at the moment. They probably will succeed before a polywell reaches net power. Which is kinds nice, cause then we can bring all that money and time to the real party. Polywell Space Transports.

I think it could be done. The real trick will be shielding from the 500KeV X-Rays (neutron absorption gammas). Neutron shielding is easy and light weight. Water (4" to 6" - 10 to 15 cm) and B10.

However, since you don't need to carry fuel (well maybe just a little for an emergency APU) you have a lot of mass available for whatever.

Cooling? Air flow should be able to handle it. With the water neutron shield handling take off rqmts (some boiling allowed). Cool it between take offs by flying at 20,000 ft and slowly venting.

It will take some thought to get the rqmts right. Maybe a failure or two. I'm pretty sure it can be done.

I see two major obstacles.

1. Shielding from X-Rays
2. Volume/weight of power conversion eqpt.

Obviously you build a few on the ground with mock up airframes before flying. I actually saw the S1W prototype from inside the building. I didn't get inside the hull. One of my instructors took me over there to have a look.

Once we get a reactor built that works the race will be on to shrink it and its associated eqpt.

Actually I was thinking of something like a C-130 carrying one of Northrop's in-development 100KW lasers (think AC-130 Spectre). Can stay up forever, shoot whatever it wants as much as it wants...

The problem with using it for cargo isn't it's weight, but the space it takes up. Heavy lifters already have problems getting vehicles on board, just due to their dimensions. You'd have to build a plane from scratch...

Mike

The problem with using it for cargo isn't it's weight, but the space it takes up. Heavy lifters already have problems getting vehicles on board, just due to their dimensions. You'd have to build a plane from scratch...

I like that kind of thinking.

Time to get out the old plans for the Spruce Goose...

Mike

Mike Holmes wrote:Time to get out the old plans for the Spruce Goose...

Mike

Yep something along those lines - at least aerodynamically.

Don't I remember a history channel episode where the air force already built a nuclear powered jet back in the cold war? I think they piped liquid sodium coolant directly to the jet engines which ran off the heat of the reactor. Of course they had to have a lead lined cockpit and irradiated the air as they flew. hahaha.

Along the lines of the Spruce Goose...

The russians had their Ekranoplans (a.k.a. caspian sea monster) which had quite the lifting power.
http://en.wikipedia.org/wiki/Ekranoplan

For kicks and giggles, see the aries
http://www.yachtboutique.com/Designers/ ... noplan.htm
Cruising speed - 450-500 km/h (250 Knots)
Range - 4000 km
Cruising flight height - 1 to 4 m
Take off weight - up to 400 t
Length overall - 73.8 m
Breadth overall - 44.0 m
Height overall - 19.2 m
Fuel stock - 80-120 t
Cargo capacity - 40 t

Cruising flight height - 1 to 4 m

Err.. miles? Meters? ???

JohnP wrote:

Cruising flight height - 1 to 4 m

Err.. miles? Meters? ???

Could be a ground effect machine.

MSimon wrote:
Could be a ground effect machine.

LOL, :-_)

Mike Holmes wrote:Time to get out the old plans for the Spruce Goose...

Mike

Haha nice one Mike

More Like "The Spruce Fuse"

The Ekranoplane is, in fact, a GEV (so that's 1 to 4 meters, yes). Which makes it an interesting possible use for fusion. As Eric points out, if you take out the fuel requirements, and simply assume that the plants are the same size (and a polywell might actually be smaller than the power plant on this beast), you'd get a huge savings in fuel tonnage, and a really large carrying capacity at much higher speeds than ships.

Unfortunately you probably still can't take it anywhere but the Black Sea or the like. At least not safely, or spending a lot of time dodging any weather.

Also it's jet powered. I jokingly suggested the spruce goose because it's the world's largest prop design ever to fly. There actually is a larger jet plane, the titanic Russian "Cossak":

http://www.aerospaceweb.org/aircraft/transport-m/an225/

If you can figure out how to power the jets with electrical output, then we can easily put a polywell fusion pant into one of these behemoths.

Now that I think about it... jets are just turbines, right?

Can anyone verify that modern aluminum or carbon frames have a higher strength/density than pine? Or had Huges hit on the best structural material possible? I note the Russians don't build the Cossak out of wood...

Mike

Mike Holmes wrote:If you can figure out how to power the jets with electrical output, then we can easily put a polywell fusion pant into one of these behemoths.

For turbojet / fanjet speeds no problem. Electric motor drives a fan / compressor. At higher speeds an electrically heated 'afterburner'. If the engine is located close enough to the reactor to run a coolant loop, heat from the reactor can be fed to the engine downstream of the fan.

Side note: I've heard that the upper speed range of a turbojet is limited by heat load on the turbine. Without a turbine in the engine higher speeds might work.

Mike Holmes wrote:Can anyone verify that modern aluminum or carbon frames have a higher strength/density than pine? Or had Huges hit on the best structural material possible? I note the Russians don't build the Cossak out of wood...

Some woods have a very nice strength/weight ratio, but getting the best from that material is more an art than a science.

kcdodd wrote:Don't I remember a history channel episode where the air force already built a nuclear powered jet back in the cold war? I think they piped liquid sodium coolant directly to the jet engines which ran off the heat of the reactor. Of course they had to have a lead lined cockpit and irradiated the air as they flew. hahaha.

It seems the U. S. never flew a prototype - but they did test nuclear-powered turbofans, according to Wikipedia. The Russians built a flying testbed and got as far as flight-testing their radiation shield.

(EDIT: The U. S. DID fly a prototype - a converted B-36 Peacemaker. It was never actually propelled by the reactor, however.)

There was also a ground test in the U. S. for Project Pluto - an unshielded (!) nuclear cruise missile said to be capable of Mach 3 at treetop level. It was supposed to loiter more or less indefinitely until told to attack...

hanleyp wrote:Without a turbine in the engine higher speeds might work.

Hopefully. I believe Bussard talked about magnetically shielding the hot section in order to increase Isp. You might be able to do that with an air-breathing engine with this kind of power available. Maybe even a magnetic nozzle for altitude compensation...?

hanelyp wrote: Some woods have a very nice strength/weight ratio, but getting the best from that material is more an art than a science.

Some very wonderful planes were wood, the 1/3 scale flying wings Northrop built, the De Havilland Mosquito was faster than a Spitfire, and carried bombs. The famous Gestapo raid was just brilliant, flying roof top thru Germany, to drop bombs on a single building.

http://www.diggerhistory.info/pages-air ... squito.htm

http://en.wikipedia.org/wiki/Northrop_N-9M