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RE: And I thought the important factor was velocity...

Unread postPosted: 07 Jul 2012, 12:26
by count_to_10
Calculations of penetration are complicated. Work is force times distance, so at first order penetration depth would be proportional to energy, but at higher order you have to figure in the fact that the force on the penetrator increases with increasing velocity, which in turn changes as the penetrator decelerates in the target.

Re: RE: Another Weapon for F-35? - HVPW

Unread postPosted: 07 Jul 2012, 13:03
by southernphantom
geogen wrote:OK, I'll bite.

So what would the current 4-5k pound bomb, modified with this same multiplying busting effect have then? Equivalent to 10,000 lb worth of bunker busting?? Wow... I guess i'd just be more worried as a bad guy, with an F-15 dropping a 10,000lb equivalent buster, than an F-22/F-35 dropping a 5k equivalent... But that's just me. ;)

I hope Stephen enjoys a well deserved holiday in beautiful Brazil.


The F-15E is rated to carry 1-3 (can't remember which) GBU-15s, which have a launch weight of around 3640lbs. I could see some kind of heavier-class weapon being a possibility for the Beagles and SAC (err...oops...meant GSC :wink:

When in doubt, apparently, add a rocket...

Re: RE: And I thought the important factor was velocity...

Unread postPosted: 07 Jul 2012, 21:49
by velocityvector
count_to_10 wrote:Calculations of penetration are complicated. Work is force times distance, so at first order penetration depth would be proportional to energy, but at higher order you have to figure in the fact that the force on the penetrator increases with increasing velocity, which in turn changes as the penetrator decelerates in the target.
Granted, it's a complicated event else r&d for this class of weapons would have ceased long ago. My goal was simply to illuminate basics in view that "potential energy" and the like were suggested. No need for diff eq's. But did you *have* to say "decelerates"? That hurts my ears. There is only acceleration :|

Re: RE: And I thought the important factor was velocity...

Unread postPosted: 07 Jul 2012, 22:17
by count_to_10
velocityvector wrote:
count_to_10 wrote:Calculations of penetration are complicated. Work is force times distance, so at first order penetration depth would be proportional to energy, but at higher order you have to figure in the fact that the force on the penetrator increases with increasing velocity, which in turn changes as the penetrator decelerates in the target.
Granted, it's a complicated event else r&d for this class of weapons would have ceased long ago. My goal was simply to illuminate basics in view that "potential energy" and the like were suggested. No need for diff eq's. But did you *have* to say "decelerates"? That hurts my ears. There is only acceleration :|

It's okay: I specified the reference frame. :wink:
Trust a Physics Ph.D: we really do use "decelerate" in scientific discussion.

RE: Re: RE: And I thought the important factor was velocity.

Unread postPosted: 07 Jul 2012, 23:15
by velocityvector
Trust a Physics Ph.D
Then you must've been awed by my simplification and the invocation of a rocket in the keester, speaking of which ... :) (I'm a CS guy turned patient liar-patent lawyer. It's been a while since I've built physical simulations, less-so for autonomous systems.)

Re: RE: Re: RE: And I thought the important factor was veloc

Unread postPosted: 07 Jul 2012, 23:55
by count_to_10
velocityvector wrote:
Trust a Physics Ph.D
Then you must've been awed by my simplification and the invocation of a rocket in the keester, speaking of which ... :) (I'm a CS guy turned patient liar-patent lawyer. It's been a while since I've built physical simulations, less-so for autonomous systems.)

Go figure.
I'm actually a cosmologist, but have been running a lot of material simulations of small scale objects.

RE: Re: RE: Re: RE: And I thought the important factor was v

Unread postPosted: 17 Aug 2012, 09:25
by spazsinbad
Air Force bunker-busting bomb program moves forward with concept-development contract to Boeing
August 16, 2012 Posted by John Keller

http://www.militaryaerospace.com/articl ... -hvpw.html

"EGLIN AIR FORCE BASE, Fla., 16 Aug. 2012. Air-launched weapons experts at the Boeing Co. Defense, Space & Security segment in St. Louis will help the U.S. Air Force design a rocket-propelled bomb for the F-35 Lightning II stealth fighter-bomber that can attack and destroy enemy bunkers, tunnel complexes, and other important deeply buried targets....

...Raytheon's Space and Airborne Systems segment in El Segundo, Calif., won a contract last January to design and demonstrate navigation and guidance technologies to keep future generations of deep-penetrating bombs and missiles on target in conditions where signals from Global Positioning System (GPS) satellite satellites are degraded or unavailable.

The contract calls for Raytheon to develop GPS-degraded munitions guidance technology as part of the Air Force High Velocity Penetrating Weapon program, which seeks to develop technologies for a future rocket-boosted bunker-busting bomb for the F-35 and other fighter-bombers.

Awarding the contract to Raytheon were officials of the Air Force Research Laboratory's Munitions Directorate at Eglin Air Force Base. Raytheon engineers will develop guidance to provide maximum penetration for a future High Velocity Penetrating Weapon, with the ability to overcome GPS-degraded environments and direct the deep-penetrating weapon to impact angles sufficient to destroy hard, deeply buried facilities.

Raytheon experts will explore weapons-guidance technologies for anti-jam GPS, angle-of-attack sensing, guidance law and autopilot, and RF seeker and guidance techniques that could support the High Velocity Penetrating Weapon's accuracy...."

Probably best to read entire article at the URL.

RE: Re: RE: Re: RE: And I thought the important factor was v

Unread postPosted: 18 Aug 2012, 01:06
by popcorn
I can't seem to access anything but the article in it's entirety but I'm curious to learn how much stand-off range the new munition will have. Assuming the rocket is reserved for the final Kamekaze dive, maybe fit a pair of swirchblade wings to allow it to glide from,a safer distance?

RE: And I thought the important factor was velocity...

Unread postPosted: 18 Aug 2012, 01:29
by madrat
The F=ma formula factors in when the impact of the mass decelerates.

RE: Re: RE: Re: RE: And I thought the important factor was v

Unread postPosted: 18 Aug 2012, 01:31
by spazsinbad
Here is one previous article (with a JDAM graphic?). This old article is very similar to article above.... Another article mentioned is the same one that started this thread? Look at the second last post on the first page of this thread for the ROCKET bomb graphics.

Raytheon to develop GPS-degraded munitions guidance for High Velocity Penetrating Weapon Posted by John Keller
January 9, 2012

"EGLIN AFB, Fla., 9 Jan. 2012. Munitions guidance experts at the Raytheon Co. Space and Airborne Systems segment in El Segundo, Calif., will design and demonstrate navigation and guidance technologies that can keep new generations of deep-penetrating bombs and missiles on target in conditions where signals from Global Positioning System (GPS) satellite satellites are degraded or unavailable. Raytheon is doing the work under terms of an $11 million contract awarded Friday by the U.S. Air Force Research Laboratory's Munitions Directorate at Eglin Air Force Base, Fla...."

http://www.militaryaerospace.com/conten ... 1/JDAM.jpg

RE: Re: RE: Re: RE: And I thought the important factor was v

Unread postPosted: 18 Aug 2012, 17:10
by arkadyrenko
Hmmm, I enjoy how the military is more or less assuming that GPS won't be around in a full scale war.

As for gliding, I think don't know if they will want to tie together the wings with the rocket pack. Logically, I suspect that to be a round 2 development. Get the rocket penetrator working and then worry about stand-off delivery.

RE: Re: RE: Re: RE: And I thought the important factor was v

Unread postPosted: 18 Aug 2012, 20:26
by spazsinbad
arkadyrenko opines: "....I enjoy how the military is more or less assuming that GPS won't be around in a full scale war...." Enjoy? Why this word choice.

RE: Re: RE: Re: RE: And I thought the important factor was v

Unread postPosted: 18 Aug 2012, 21:46
by arkadyrenko
I enjoy it because it is a critical, and under-reported, change in military planning for the future. It marks a fundamental change from the past 20 years, when GPS and precision bombing was all the rage, to a more realistic and more interesting future.

As it portends a return to great-power military development, much more interesting than anti-terrorism, and a new wave of technological development it is pretty interesting to me.

In either case, whether or not I enjoy it, it is a fact and will spawn a whole host of interesting elements in the future. (It also represents a potential advantage for the US, if the US can fight in a GPS denied environment, the US won't have any fear about denying GPS (or the Chinese equivalent) as part of a theater wide EW strategy)

Re: RE: Re: RE: Re: RE: And I thought the important factor w

Unread postPosted: 19 Aug 2012, 00:06
by popcorn
arkadyrenko wrote:Hmmm, I enjoy how the military is more or less assuming that GPS won't be around in a full scale war.

As for gliding, I think don't know if they will want to tie together the wings with the rocket pack. Logically, I suspect that to be a round 2 development. Get the rocket penetrator working and then worry about stand-off delivery.


Not much mystery or risk involve in developing a pair of wings for glide capability.. even getting the rocket technology right shouldn't be a big deal.

Re: RE: Re: RE: Re: RE: And I thought the important factor w

Unread postPosted: 19 Aug 2012, 00:53
by count_to_10
arkadyrenko wrote:I enjoy it because it is a critical, and under-reported, change in military planning for the future. It marks a fundamental change from the past 20 years, when GPS and precision bombing was all the rage, to a more realistic and more interesting future.

As it portends a return to great-power military development, much more interesting than anti-terrorism, and a new wave of technological development it is pretty interesting to me.

In either case, whether or not I enjoy it, it is a fact and will spawn a whole host of interesting elements in the future. (It also represents a potential advantage for the US, if the US can fight in a GPS denied environment, the US won't have any fear about denying GPS (or the Chinese equivalent) as part of a theater wide EW strategy)

At some point, the enemies of the US are going to deploy GPS guided weapons. I wonder how far along we are with area denial for that.