Forum: F-22A Raptor

It never flew in Project Pluto...

I remember reading about Project Pluto in an Air&Space Magizine years ago...

Here is some of it's Wikipedia article:

"Once powered up, the unshielded half-gigawatt nuclear reactor would emit highly lethal radiation in a large radius; such a vehicle could not possibly be human-piloted or reused. Indeed, some questioned whether a cruise missile derived from Project Pluto would need a warhead at all; the radiation from its engine, coupled with the shock wave that would be produced by flying at Mach 3 at treetop level, would have left a wide path of destruction wherever it went. The SLAM as proposed would carry a payload of many nuclear weapons to be dropped on multiple targets, making the cruise missile into an unmanned bomber. Contrary to some reports, the exhaust of the engine would not itself be highly radioactive."

If anyone is interested; check out this site... WOW!
http://www.bisbos.com/rocketscience/air ... actor.html

The production reactor was suppose to be good for 600 MW. To put that in perspective that's nearly 805,000 hp compared to 280,000 hp of your average Nimitz class.

Yeah, but it would take an awfully big solid rocket to get a Nimitz class carrier up to the speed where a ramjet would be useful though.

Just kidding, that actually does provide an interesting perspective.

My first thought was "## #### sherlock" as Pluto never flew but I'll bite, WHAT never flew in Pluto?

The reactor was never flown...thought it was obvious, sorry.

Where did I say the reactor flew?

Where did I say the reactor flew?

I was just adding to what you brought up...not many people have heard of that project and it was a very interesting idea.

Raptor One,

Good Code 1 article by Joe Bill. I worked with him on many test flights and always respected his comments. Several points to consider. First, when he mentioned going 845 kt in a test flight you can be sure that condition was approved by Engineering well before the flight and the test was closely monitored during the flight. Flight test limits are not always the same as operational limits. Under controlled and monitored test conditions, you can do things that would be unsafe in operational usage. It was necessary to go that fast to clear the handbook limit of 800 kt. Second, his comments about the engine failure are correct. As I said earlier, I did not know if those details had been released, so I wasn't about to do it myself.

Next, his comments about the canopy are correct, BUT exactly the same thing could be said about every part of the airplane. So pointing out potential canopy problems makes no sense, when everything on the airplane has the same potential for disaster. The real point is, no one knows what would happen, because no one has done any analysis or testing to find out what the problems would be at 900 or 950 kt.

The case of the XL elevon failure was not exactly as he stated. The airplane response and resulting structural failures were as described, but the failure was caused by a poor design of the elevon horn, which failed at 88% of limit load due to a durability crack. Since only two XLs were built, there was no budget for durability ground test. So what we thought was a conservative design was used. Bad choice. I was monitoring the elevon load when it failed and couldn't believe my eyes when the load indication dropped to zero instantly at the time of failure. There was no indication of a control system failure since the elevon position was monitored on the actuator and it continued to move in response to computer commands as if nothing had happened. It just wasn't connected to the elevon any longer. I think Joe Bill was trying to be kind to the Structures group for our bad design.

Joe Bill's comments about testing locked control surfaces eventually led to development of new control laws which automatically reconfigured the surface commands in case of a surface failure. I'm not sure if those control laws were ever adapted to the F-16, but they were installed on the IDF and T-50. Here's how they work. Say a horizontal tail fails and is locked at zero. Any pitch command to the tails is doubled for the remaining tail, but that would also cause the airplane to roll. So a corresponding anti-roll command is sent to the ailerons. Similar logic is used in case of aileron or rudder failure. Those are simply "get home" functions and are not intended to maintain any combat capability.

Good Code 1 article by Joe Bill. I worked with him on many test flights and always respected his comments.

Joe Bill's comments about testing locked control surfaces eventually led to development of new control laws which automatically reconfigured the surface commands in case of a surface failure. I'm not sure if those control laws were ever adapted to the F-16, but they were installed on the IDF and T-50.

Heat? Not a problem, since it gets much hotter at 2.0 mach at higher altitudes.