Impact fuze threshold forces

#1
Can anyone provide me with a rough estimate of the threshold force necessary to trigger an impact fuze on typical weapons faced by our troops?

I need to do some design estimates for a research proposal.

Thanks.
 
#2
Are you talking RPGs, underslung grenades, AP mines, AT mines or pressure pads?
 
#3
Are you talking RPGs, underslung grenades, AP mines, AT mines or pressure pads?
Oops I realise it wasn't clear in my question. The research proposal is on a vehicle/base protection system against guided/unguided rockets, artillery and mortars.

I'm focussing on the RPG-7 rockets used by insurgents against our forces because of its urgency.

But also in a broader context, what sort of force thresholds apply for impact fuzes which may be encountered by our forces in the future, e.g. RPG-22, 28, 30, AT-3 Sagger, AT-14 Kornet. If you have data for mortar and artillery shells used by the enemy, it'd be great too.

If one must be shy about specific numbers then order of magnitude will do.
 
#4
Bar armour is working great thanks :D

Don't know have a look at Janes defense.

After reading another of your posts, I'm sure all you're doing is making up patents and registering them in the hope that someone makes a system which you can then pursue them in court for damages?
 
#7
If that’s the case then I apologise.

With regards to your answer to your question putting a logical engineers head on it you could probably assume it won't take much in the way of a force to initiate an impact fuze due to the nature of an impact fuze :)

And in theory the bar armour and extra slab armour will probably withstand most AT weapons thrown at it except maybe top attack variants and together with reactive armour in most modern armies arsenals they've probably got most things covered for the time being.
 
#8
Independent Boffin, are you also perstering the BAE systems naafi queue?
The Armny rumour Service is primarily full of people who either: once did, do, or intend to pull triggers and shoot things.
It is for the most part not populated by people who give a flying fvck how the bullet came out of the end, how fast it came out of the end, how many grooves were in the barrel, how many twists their were or whether it was a left or right hand twist.

We are just simple soldier folk, we know what we like, if we dont like it we will tell you, if we were american we would debate .45 Vs 9mm all day long but ultimately, weapons are a tool that we get given to do a job, and just as bad workmen blame their tools we (if I may speak for other people) dont feel the need to constantly redesign kit in order that we can do our job better.

You dont ask people that drive a toyota prius how to lessen its drag coefficient,
You wouldnt ask Gordon Ramsay how to make a convection oven faster to come up to temperature.
You dont ask cashiers in the building society how to stabilise the Irish economy.

This is not the audience to pry for information, weapons designers, gunsmiths or whatever they are called, arent in the army. I appreciate you are trying to garner opinion and support for your ideas, but as you dont appear to have any ideas at the moment your just a bit irritating. A squaddie who leaves the army and works for a consultancy is their o his merit and his experience, he actually understands what it is that he is trying to sell.

............. Must dash, need coffee!
 
#9
IndependentBoffin is right. Bar armour only works against RPG-7. It may have a small effect against other HEAT-type warheads, but something like a Kornet will go right through it and out the other side of anything short of an MBT, and it would probably do for that as well.
 
#10
Quite possibly but the threat the vehicles are exposed to in current theatre they are a match, maybe I should have said hand held AT weapons.

Reactive armour was developed and purchased by an already strapped for cash MOD in this day and age the money is not there to purchase anything to defeat possible future threats that at this moment are not on the agenda, the problem with Boffins are that the ideas are normally so far fetched that practicallity and cost often stop the idea being made.

Until reactive armour is defeated or Bar Armour is defeated then the next evolution in Anti Armour weapon defence will not even come up.
 
#11
There are a myriad fuze types, across a range of weapons systems.

In terms of RPG-type systems, some (PG-7) use am impact sensitive piezo-crystal in the nose, others use graze fuzes, some use inertia fuzes. Most of these weapons are characterised by Defence Intelligence, but unsuprisingly, the information is not available in the public domain!
 
#12
I rather doubt that the MoD will wait until a new threat develops before trying to counteract it. Better for all to work out the solution so you have it if you need it. If you have a good solution that others want then you can license it and make a bit of money. I think that might be what IB is up to.
 
#13
There are a myriad fuze types, across a range of weapons systems.

In terms of RPG-type systems, some (PG-7) use am impact sensitive piezo-crystal in the nose, others use graze fuzes, some use inertia fuzes. Most of these weapons are characterised by Defence Intelligence, but unsuprisingly, the information is not available in the public domain!
I'm guessing that the Soviets, while not particularly known for their H&S Legislation, would not want the threshold force to be under the self-weight of the rocket, in the event that some clueless private decides it is a good idea to stack the rockets vertically downwards. The rockets may have an arming distance but components can fail so any good designer would take this into account.

Given that the mass of a PG-7V rocket is 2.6 kg, I'm making an educated guess that the threshold force is above 25N. Say 100N.

Out of curiosity G_B even if I was working at DSTL would such information be need-to-know and unavailable to me for the purposes of a speculative research proposal?
 
#15
And why are these figures not publically available anyway? If they pertained to our weapons I can understand but if they pertain to the adversaries'?
You've just answered your own question, We restrict our information they restrict their information, that’s why????
 
#16
Independent Boffin, are you also perstering the BAE systems naafi queue?
The Armny rumour Service is primarily full of people who either: once did, do, or intend to pull triggers and shoot things.
It is for the most part not populated by people who give a flying fvck how the bullet came out of the end, how fast it came out of the end, how many grooves were in the barrel, how many twists their were or whether it was a left or right hand twist.

We are just simple soldier folk, we know what we like, if we dont like it we will tell you, if we were american we would debate .45 Vs 9mm all day long but ultimately, weapons are a tool that we get given to do a job, and just as bad workmen blame their tools we (if I may speak for other people) dont feel the need to constantly redesign kit in order that we can do our job better.

You dont ask people that drive a toyota prius how to lessen its drag coefficient,
You wouldnt ask Gordon Ramsay how to make a convection oven faster to come up to temperature.
You dont ask cashiers in the building society how to stabilise the Irish economy.

This is not the audience to pry for information, weapons designers, gunsmiths or whatever they are called, arent in the army. I appreciate you are trying to garner opinion and support for your ideas, but as you dont appear to have any ideas at the moment your just a bit irritating. A squaddie who leaves the army and works for a consultancy is their o his merit and his experience, he actually understands what it is that he is trying to sell.

............. Must dash, need coffee!
So tell me why are the army not still using the Martini-Henry or the SMLE .303? Or for that matter still trotting about the empire on horses? It is because of the work the weapon and defensive weapon designers that people are alive today that in anothet time would have been dead. The bloke may be a boffin, but he was only asking a civil question.
 
S

Snoreador

Guest
#17
Also, if "we" know about enemy weapon characteristics, "we'd" hardly disclose the fact. That would just invite them to make something new. Secrecy works both ways, and then back again.
 
#18
I'm guessing that the Soviets, while not particularly known for their H&S Legislation, would not want the threshold force to be under the self-weight of the rocket, in the event that some clueless private decides it is a good idea to stack the rockets vertically downwards. The rockets may have an arming distance but components can fail so any good designer would take this into account.

Given that the mass of a PG-7V rocket is 2.6 kg, I'm making an educated guess that the threshold force is above 25N. Say 100N.

Out of curiosity G_B even if I was working at DSTL would such information be need-to-know and unavailable to me for the purposes of a speculative research proposal?
Not quite as simple as that, as warheads are armed approx 5m after firing, and no ammount of squeezing could get an unarmed warhead to go off. There's also the issue of static vs dynamic forces...i.e. the length and magnitude of the stress pulse from impacting a material.

In answer to your last question, if you were working for Dstl, then you would probably be doing the research yourself!
 
#19
Not quite as simple as that, as warheads are armed approx 5m after firing, and no ammount of squeezing could get an unarmed warhead to go off. There's also the issue of static vs dynamic forces...i.e. the length and magnitude of the stress pulse from impacting a material.

In answer to your last question, if you were working for Dstl, then you would probably be doing the research yourself!
The electrical energy produced from the piezoelectric crystal in the fuze comes from work done on it. Hence Force x distance. The stroke length of the fuze is a fixed design parameter, hence the impact force is the determinant of available mechanical energy to be converted to electrical energy.
 
#20
Googles awesome

he VP-7M fuze is used with anti-tank hollow-charge grenades and serves to detonate the warhead on impact with the target. The fuze is a safety, impact, piezoelectric type with distant arming. It is used with the PG-7 and PG-7M rounds.
48 sets of fuzes in 4 metal boxes in a wooden case
Dimensions /mm/ 520 x 500 x 171
Volume / m3 / 0,037
Weight /kg/ 22
Type:piezoelectric, nose-base,with distant arming and self-destruction
Action:percussion, instantaneous
It is activated at an angle of impact with the target: from 0° up to 60°
Self-destruction time / s / from 3,8 to 6
Distant arming / m / from 3 to 15
Height of safe fall / m / 3
Weight / kg /: 1
- piezogenerator 20,0412
- base part 30,096

From the safe fall height and the weight of the item you can work out the N that won't set it off.

Amature first port of call is google
 

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