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5 inch rocket with warhead Mk 25 Mod 1

Antoon

Well-Known Member
Ordnance approved
Hello,

Has someone a good cut-away drawing of the 5 inch rocket warhead Mk 25 Mod 1 filled with 16 lb. comp B.

Greetings - Antoon


Schermafbeelding 2020-05-17 om 22.33.49.jpg
 
Or the Zuni 5". They used the same warhead as the HVAR .

Mk25, Mk32 Mod 0 and Mod 1(Prac) are the same.

'5.0-Inch Rocket Head Mk 32 Mod 0 (ATAP)

The Mk 32 Mod 0 rocket head, antitank, antipersonnel (ATAP)
is shown in Figure 4. Used in ZUNI, this head with a point
detonating (PD) fuze (Mk 188 Mod 01 effects shaped-charge action.
Thus, it is highly effective against heavy targets such as tanks or
bunkers. The Mk 32 head has a cavity liner to prevent exposing
the explosive when fuzes are changed. For fragmentation action
against aircraft or personnel, a proximity fuze CM 414) may be attached to the head'.

mk32mod.Capture.PNG
 
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It doesn't say much for the Smithsonian when they don't know the difference between a rocket and a missile.
 
Or the Zuni 5". They used the same warhead as the HVAR.

Mk25, Mk32 Mod 0 and Mod 1(Prac) are the same.

The documentation I have states they are similar, but not the same.

The MK 32 MOD 0 has an internal stress riser plastic liner to control the fragmentation of its approx. 1/8" (3.175 mm) casing around the charge. I don't think this was brought in until far later. Possibly after the UK shared data with the US. The UK had developed these liners that are sometimes referred to in the UK as 'Buxton Liners', after the research establishment that developed them.
 
The Mk32 Mod1 Practice warhead i have is just an inert repainted Mk25. I can still see the original stencilling (Mk25 Mod1) enough under the Blue painted, re-stencilled practice loading. Noting the new stencilling has '5" Inert weight of filler 16lbs'. The liner may be the main difference between the Mod 0 and Mod 1?.
 
The Mk32 Mod1 Practice warhead I have is just an inert repainted Mk25. I can still see the original stencilling (Mk25 Mod1) enough under the Blue painted, re-stencilled practice loading. Noting the new stencilling has '5" Inert weight of filler 16lbs'. The liner may be the main difference between the Mod 0 and Mod 1?.

It's more likely the MK 32 was developed from the MK 25 series, most likely incorporated improvements, such as fragmentation control through the use of the plastic (stress-riser) liner, as seen on later Russian 30 and 40 mm grenades, and other changes.
The documentation I have states that the MK 25 MOD 1 and 2 were both normally HE-loaded, 15.33 lbs of Comp B. Details on the MK 32 MOD 1 rocket, that uses the MK 25 MOD 1 and MOD 2 warheads is below. Note there's nothing there about a plastic liner.

5-inch HVAR MK 32 MOD 1 Rockete Details - 1.png5-inch HVAR MK 32 MOD 1 Rockete Details - 2.png

I don't have a cutaway of the MK 25, but data and an image of the MK 32 MOD 0 are below, along with the info and an image of the MK 24 MOD 0 GP.

5-inch HVAR MK 32 MOD 0 APAT & MK 24 MOD 0 GP Warheads - 1.jpg5-inch HVAR MK 32 MOD 0 APAT & MK 24 MOD 0 GP Warheads - 2.jpg
 
According to document you attached, the Mk.25 nad Mk.32 warheads definitely couldn't be the same design. The penetration parameters for Mk.32 are much higher than values for Mk.25.

Some years ago someone on warthunder forum linked US report from 1952 about HVAR fuzes testing. There was an information Mk.25 warhead with one of these fuzes detonates properly when hit the target even at 70° obliquity and could easily penetrate 3,5 in (89 mm) od armor. That means about 10,35 in (263 mm) at 0°.

In document you attached the penetration of Mk.32 is given as 7 in (178 mm) at 65° and 18 in (457 mm) at 0°.
 
According to document you attached, the Mk.25 nad Mk.32 warheads definitely couldn't be the same design. The penetration parameters for Mk.32 are much higher than values for Mk.25.

Some years ago someone on warthunder forum linked US report from 1952 about HVAR fuzes testing. There was an information Mk.25 warhead with one of these fuzes detonates properly when hit the target even at 70° obliquity and could easily penetrate 3,5 in (89 mm) od armor. That means about 10,35 in (263 mm) at 0°.

In document you attached the penetration of Mk.32 is given as 7 in (178 mm) at 65° and 18 in (457 mm) at 0°.

The first document was from 1955 'OP 1415 - Rocket Assemblies', the second was from 1960 'OP 2626 - 5.0-Inch High-Performance Folding-Fin Aircraft Rocket Zuni - Description Operation & Maintenance'.

As to the MK 32 being based on the MK 25, the common shape, lengths, technical features and the fuzes used makes it highly likely this is true. The MK 32 would seem to be an improved version of the MK 25, but without technical drawings showing the latter's internal features, the exact changes, other than the plastic liner in the former, is unclear.

As to penetration, don't fall into the trap of simply saying X has this penetration at this Y° inclination and then, by simple maths, stating it has this penetration against vertical plate (0° or 90° depending on your point of reference).

As can be seen in the text, the MK 32 MOD 0 had a penetration of approximately 7 inches (177.8 mm) into a plate that was inclined at 65° from the vertical (25° from the horizontal), but 8 inches (457.2 mm) against a vertical plate.

If we use the simple maths way of calculating the equivalent thickness of plates when inclined (equation below).

Thickness (equivalent) = Thickness (penetrated, plate perforated, etc.) ÷ Cos (angle of inclination from vertical)°

Then if we take the 7-inch (177.8 mm) penetration at 65°, that's equivalent to 16.6-inches (420.7 mm) against vertical plate. This figure does not agree with what is stated, i.e. 18 inches (457.2 mm).

The reason for this discrepancy... many, but most likely fuzing- and projectile geometry-related in this case.

In fact, there's another document (research paper) about a modification to the MK 149 fuze titled 'Experimental Ballistic Teat of Modified Mk 149 Nose Fuze' that shows the sort of problems that can occur. In one case the high inclination resulted in the warhead having a HESH/HEP like effect. This is likely due to the warhead body collapsing and being squashed against the plate, the fuze not functioning until it and the charge were squashed together, or the fuze struct another object.

What's the moral of this story, the depth of penetration doesn't always have a simple relationship with inclination. Other similar examples would be the ricochets, or break up of tungsten carbine cores due to high angles of inclination
 
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According to document you attached, the Mk.25 nad Mk.32 warheads definitely couldn't be the same design. The penetration parameters for Mk.32 are much higher than values for Mk.25.

Some years ago someone on warthunder forum linked US report from 1952 about HVAR fuzes testing. There was an information Mk.25 warhead with one of these fuzes detonates properly when hit the target even at 70° obliquity and could easily penetrate 3,5 in (89 mm) od armor. That means about 10,35 in (263 mm) at 0°.

In document you attached the penetration of Mk.32 is given as 7 in (178 mm) at 65° and 18 in (457 mm) at 0°.
The Mark 25 warhead is for the HVAR system, Mk32 warhead is for the Zuni. They're completly unrelated.

I think your confusion stems form the existence of the Mk32 rocket (Not warhead), which is a Mk25 warhead with Mk 149 fuze on a Mk 10 motor. Check OP 2210 Aircraft Rockets

The first document was from 1955 'OP 1415 - Rocket Assemblies', the second was from 1960 'OP 2626 - 5.0-Inch High-Performance Folding-Fin Aircraft Rocket Zuni - Description Operation & Maintenance'.

As to the MK 32 being based on the MK 25, the common shape, lengths, technical features and the fuzes used makes it highly likely this is true. The MK 32 would seem to be an improved version of the MK 25, but without technical drawings showing the latter's internal features, the exact changes, other than the plastic liner in the former, is unclear.

As to penetration, don't fall into the trap of simply saying X has this penetration at this Y° inclination and then, by simple maths, stating it has this penetration against vertical plate (0° or 90° depending on your point of reference).

As can be seen in the text, the MK 32 MOD 0 had a penetration of approximately 7 inches (177.8 mm) into a plate that was inclined at 65° from the vertical (25° from the horizontal), but 8 inches (457.2 mm) against a vertical plate.

If we use the simple maths way of calculating the equivalent thickness of plates when inclined (equation below).

Thickness (equivalent) = Thickness (penetrated, plate perforated, etc.) ÷ Cos (angle of inclination from vertical)°

Then if we take the 7-inch (177.8 mm) penetration at 65°, that's equivalent to 16.6-inches (420.7 mm) against vertical plate. This figure does not agree with what is stated, i.e. 18 inches (457.2 mm).

The reason for this discrepancy... many, but most likely fuzing- and projectile geometry-related in this case.

In fact, there's another document (research paper) about a modification to the MK 149 fuze titled 'Experimental Ballistic Teat of Modified Mk 149 Nose Fuze' that shows the sort of problems that can occur. In one case the high inclination resulted in the warhead having a HESH/HEP like effect. This is likely due to the warhead body collapsing and being squashed against the plate, the fuze not functioning until it and the charge were squashed together, or the fuze struct another object.

What's the moral of this story, the depth of penetration doesn't always have a simple relationship with inclination. Other similar examples would be the ricochets, or break up of tungsten carbine cores due to high angles of inclination
I found a paper on DTIC giving information on all sorts of shaped charges. It states the Mk.25's fuze is good for angles up to 65 degrees and the head will penetrate about 16 inches of armor at 0 degrees.

You'll need to Control-F for "Mk 25" to find the info, there are several papers on the subject. Oh, and it actually confirms the existence of the mythical British 3" RP/ "60 pounder" rocket's shaped charge warhead

It's more likely the MK 32 was developed from the MK 25 series, most likely incorporated improvements, such as fragmentation control through the use of the plastic (stress-riser) liner, as seen on later Russian 30 and 40 mm grenades, and other changes.
The documentation I have states that the MK 25 MOD 1 and 2 were both normally HE-loaded, 15.33 lbs of Comp B. Details on the MK 32 MOD 1 rocket, that uses the MK 25 MOD 1 and MOD 2 warheads is below. Note there's nothing there about a plastic liner.

View attachment 160881View attachment 160882

I don't have a cutaway of the MK 25, but data and an image of the MK 32 MOD 0 are below, along with the info and an image of the MK 24 MOD 0 GP.

View attachment 160879View attachment 160880
I think you're confusing rocket types. Mk25 is the HEAT warhead for the HVAR. Fully assembled with fuze and motor it is the Mk 32 rocket.

Mk 32 warhead is for the Zuni system, and is known as the Mk 41 rocket once assembled with motor and fuze. Mk24 is also a Zuni warhead.


The Navy used to designate a fully assembled rocket as "X-Inch Rocket Mk XX Type", with no regard for there possibly being a warhead, motor, or fuze that is the name Mk number. By the time the Mk34 WP head for Zuni came out in the mid-1960s, they had dropped this.
 
I'm so tired of this sort of reply...

Do you really think I don't know one type of rocket from another and their nomenclature? This especially as I have many, many 5" and other US rocket manuals from WWII to the present?

I'm certainly not mixing up the MK and MOD designations of complete rockets with their heads. The '5.0" Rocket MK 32 MOD 1' is armed with either the MK 25 MOD 1 or MOD 2 warhead ('head' in abbreviated terms). The MK 32 warhead series is used with the '5.0" Folding Fin Aircraft Rocket (Zuni) (ATAP) MK 41 MOD 0', or MOD 1. The MOD 0 using the MK 188 MOD 0 PD fuze and the MOD 1 using the M414 (T2061) VT fuze. ATAP being an abbreviation for Anti-Tank Anti-Personnel.

Also, if you can't tell the MK 32 has a lineage that leads back to the MK 25 used by the HVAR (High Velocity Aircraft Rocket) I suggest you need to go and see an optician. They aren't exactly the same, no, their noses differ slightly in shape, but they are far too common in design not to be related. Their HE masses are almost identical and even OP 2626 states they are similar! Find a cutaway that shows what the MK 25 is really like inside and that will settle the matter once and for all. Good luck finding it, but if you do, brill.

Hmm, shaped charges, I know nothing about those (I'm being sarcastic). I was only the go-to person at Jane's (Janes now) on warhead mechanics and have a rather 'large' library (physical and electronic) on the subject.

Finally, as per the MK and MOD system (MIL-STD-1661), it is MK or MARK, and MOD, plus EX instead of MARK/MK for experimental equipment. There are no dots, no hyphens, they aren’t closed up and they are only mixed case in non-technical texts, and they certainly should not mixed case on marked-up (stencilled) equipment.
 
I'm so tired of this sort of reply...

Do you really think I don't know one type of rocket from another and their nomenclature? This especially as I have many, many 5" and other US rocket manuals from WWII to the present?

I'm certainly not mixing up the MK and MOD designations of complete rockets with their heads. The '5.0" Rocket MK 32 MOD 1' is armed with either the MK 25 MOD 1 or MOD 2 warhead ('head' in abbreviated terms). The MK 32 warhead series is used with the '5.0" Folding Fin Aircraft Rocket (Zuni) (ATAP) MK 41 MOD 0', or MOD 1. The MOD 0 using the MK 188 MOD 0 PD fuze and the MOD 1 using the M414 (T2061) VT fuze. ATAP being an abbreviation for Anti-Tank Anti-Personnel.

Also, if you can't tell the MK 32 has a lineage that leads back to the MK 25 used by the HVAR (High Velocity Aircraft Rocket) I suggest you need to go and see an optician. They aren't exactly the same, no, their noses differ slightly in shape, but they are far too common in design not to be related. Their HE masses are almost identical and even OP 2626 states they are similar! Find a cutaway that shows what the MK 25 is really like inside and that will settle the matter once and for all. Good luck finding it, but if you do, brill.

Hmm, shaped charges, I know nothing about those (I'm being sarcastic). I was only the go-to person at Jane's (Janes now) on warhead mechanics and have a rather 'large' library (physical and electronic) on the subject.

Finally, as per the MK and MOD system (MIL-STD-1661), it is MK or MARK, and MOD, plus EX instead of MARK/MK for experimental equipment. There are no dots, no hyphens, they aren’t closed up and they are only mixed case in non-technical texts, and they certainly should not mixed case on marked-up (stencilled) equipment.
How am I supposed to know who you are or what manuals you have?

I saw what looked like people confusing two rocket types for each other so I attempted to clarify.


And yeah, of course the Mk 25 and Mk32 warheads are related. They're shaped-charge warheads of the same size developed by the same people about a decade apart.
 

enough
the last few posts in this thread are starting to get a bit heated
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We have members who know nothing and members who know quite a lot.
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