b61 nuclear missile video at the Tonopah Test Range

The copyright is 2015, so I assume this is one of last year's tests. The video was uploaded 3/31/2016.

b61 test

At one point in the video, the missile spins, but most of the flight seems unpowered. I'm going to assume it hit the ground spinning.

originally posted by: gariac
The copyright is 2015, so I assume this is one of last year's tests. The video was uploaded 3/31/2016.

b61 test

At one point in the video, the missile spins, but most of the flight seems unpowered. I'm going to assume it hit the ground spinning.

Think rifle ballistics and the barrel "rifling" that gives it the name. The bullet is set to spin for accuracy.

a reply to: Gothmog

Centrifugal force is something else. Weird how spin for engineers is different from political conversation.

a reply to: gariac

Cool video however I would say that is a bomb, not a missile.

A powered, guided munition that travels through the air or space is known as a missile (or guided missile). A powered, unguided munition is known as a rocket. Unpowered munitions not fired from a gun are called bombs whether guided or not; unpowered, guided munitions are known as guided bombs or smart bombs.

And yes you could see it was still spinning as it hit the ground.
Spinning keeps it stable and pointed in the right direction.

Only down side to that video was the lack of boom boom.

a reply to: ShadowLink

i was going to say that the B61 is not a missile, it's a bomb. i use to see them everyday.

this is turning what was once a dumb bomb into a smarter bomb.

a reply to: gariac

here is what i think your video is from,

The “full-system mechanical environment test” was the first in a line of assessments intended to verify how the B-61 bomb’s new “Mod 12” variant would behave under routine conditions or accident scenarios, the National Nuclear Security Administration said in a statement. The review included use of an Air Force-developed ”tail kit” intended to improve targeting accuracy for the updated bomb, which is to eventually stand in for several earlier versions.
U.S. Conducts ‘Successful’ Test of an Updated B61 Nuclear Bomb

checked the date and the one i posted is older than yours, but i satell think it's part of the testing of them. the B-61 has been around for at least 40 years.
one of my duty stations, i use guard them when i was in the Corps.

also if not mistaken, there was a thread about it.

a reply to: hounddoghowlie

I ran a search and found my other thread on these tests, but there was no video, hence the new thread. I suppose I could have updated the old thread.

I will go with bomb versus missile, but there does seem to be a short powered phase when then set it spinning, which is why a had used missile originally.

a reply to: gariac

i could see how you could mistake that.
what your seeing is what i would think are rockets to start the spin of the bomb. kinda like the assist rockets used for some older aircraft on take off.

Here are a few links to explain some of the emblems at the end of the video:

en.wikipedia.org...

Not too many facts here.
www.kirtland.af.mil...

en.wikipedia.org...


en.wikipedia.org...

www.sandia.gov...

The link is for a Sandia "lab news" issue that has three pages dedicated to the TTR and one of the B61 tests.

Note that they did the B61 test just after sunrise for best optical clarity. It wouldn't surprise me if that is standard practice for any test at the range involving optics.

a reply to: gariac

Overhauling the Nation’s Nuclear Arsenal

Spin motion is needed to stabilize the bomb as it glides toward its target. It’s controlled by rocket motors and slanted fin tails. But in earlier B61 designs, air plumes from the motors have interfered with fin performance, thus weakening the push, or torque, created by the motors and reducing spin rates.

I find the spin interesting. I'm familiar with the process, from past work I've done. However, the spin-stabilized bodies usually required 200 Hz spin rates, not the lower ~10 Hz we see from the test film. Generally speaking, the fin-stabilized projectiles need to spin at 10 Hz to equalize any offset in a rocket motor thrust vector, and this is done either by fin cant or an asymmetric chamfer of the leading edge.

Considering the B-61 is fin stabilized and does not require a rocket motor for thrust, nor gas generator, I find it odd they have a need for spin at all. The only basis I can imagine is to compensate for an accidentally bent fin during weapons handling, thus allowing for better CEP accuracy in the end. Suppose it's better to be fairly accurate than to be far off in the case of a bent fin. But, in reality these are nuclear weapons that don't need pinpoint accuracy.

So again, without the tight CEP requirement, spin leaves me confused. The only remaining need I can see beyond CEP, or aerodynamic static margin is arming the physics package by way of a minimum spin rate. It would certainly be a failsafe method and could be a final arming step beyond pulling an umbilical. Beyond spin induced aerodynamically by the fins (limited by dynamic pressure - B-61 drop airspeed and altitude), the rocket motors would be a certain method of achieving the needed spin rate to arm.

Any further thoughts or links substantiating the need to spin? Not to sound like a conspiracy theorist, I don't think we're getting the whole story on the need for a spin rate.

To support the position, the JDAM does not require a spin rate that I'm aware of, and is a similar gravity bomb with a tailkit setup. The point of the JDAM is the significant increase in CEP accuracy in dropping a Mk 84.

For some reason, reading those articles turns my stomach. The military and contractors write in coded, yet proud language, that describes how they make these nuclear weapons more reliable, accurate, updated, etc..

Yet, all I see in my mind are thousands of innocent children maimed for the rest of their life because of these "improved" weapons.

How the U.S. is willing to use these bombs, while making it illegal to pour water over a terrorist's face, is a totally insane train of thought. (imo)

a reply to: carewemust

Rest assured, the US is not going to nuke anyone. Well not anymore. The fact these weapons won't be used is a problem in that the field doesn't exactly attract the best and brightest in the military. Hence all the screw ups, test cheating, etc. Nukes in the DoD is a dead end job.

From an engineering/physics standpoint, those people are fine with the projects since tech is tech. The sub-critical tests are a real mental challenge. You have to convince the powers that be that the nuke will go off without actually going critical. Compound this with the fact that I doubt anyone at the DOE today has ever been involved with an actual nuclear explosion. Those people have retired long ago and most likely aren't even alive.

a reply to: TAGBOARD

These bombs are ground penetrating to some degree. Does the slow spin help with that?

a reply to: gariac

Here is another view:

www.youtube.com...

originally posted by: Shadowhawk
a reply to: gariac

Here is another view:

www.youtube.com...

This is obviously USAF B-roll, but I can't find it on the DVIDS website.
www.dvidshub.net...

Maybe it is the camera perspective, but the bomb seems to be horizontal while falling, which makes the spin be kind of useless.

Video: America's Nuclear Bomb Gets a Makeover

Minute 4 discusses the dial-a-yield capability, which requires a tighter CEP, due to the smaller blast effect radius. This is a correction to my above statement for little need for accuracy.

a reply to: gariac

I think you are right. I was able to confirm independently that the spin is for ground penetration purposes for some variants, not flight dynamics (stability and control).

a reply to: TAGBOARD

Another possibility is the spin creates friction which acts like a retarder. The video points out no parachute is used.

It appeared to me that just before the bomb hit the target, there was propellant.

a reply to: gariac

I guess I don't understand Solid Mechanics well enough to know what the use of a retarder would do.

Regarding the "puffs" of propellent that appear just prior to impact, I can only think of two reasons. One is to increase the airframe kinetic energy at the last moment, to increase penetration distance. The other is at the terminal phase, radial thrusters might be placed near the center of mass to make last moment trajectory adjustments to position, or near the nose or tail to adjust attitude prior to impact. The former would be for better CEP accuracy and the other may be to adjust the oblique angle at impact. All just guesses.