The .05 warhead weight multiplier for rockets and tac missiles is official (from JTAS, may have been changed in later printings), but it's also completely bonkers. Just look at the real-world examples I cited. You can't make an effective HE warhead that light because you need fragmentation material and/or a pressure casing to keep the explosive filling from scattering itself everywhere before it can burn.

Tom, the rockets in that manual are bazooka rounds, which are in no way equivalent to aircraft rockets. The warheads are inefficiently light and the velocity is too low to use them safely (a jet aircraft in a dive could literally catch up to them and shoot itself down; this has happened with cannon rounds, and apparently happened to a Dutch F-16 last month).

Ethan

On Thu, Apr 25, 2019 at 8:34 PM Thomas RUX <xxxxxx@comcast.net> wrote:

Evening from WA Ethan McKinney and David Jaques-Watson,


Thank you both for the reply to my question about the MT COACC rockets and missile pods.


I am grateful that David walked through the process of designing the warheads since his works showed me that the CT Striker Book 3 DS9 spreadsheet I made a few years ago had issues which are being corrected. I am working to revamp the entire DS9 spreadsheet.


My new spreadsheet's warhead numbers matched those David worked out. So far I've completed the 80mm HE rocket with the results as follows provided that I understood the instructions:

Warhead: Weight = 0. 7 kg; Price = Cr.5.6

Rocket Motor: Weight = 0.7 kg; Price = Cr0.7


I have a link to a 1945 copy of Rockets and Launchers from the USA that can be found at http://cgsc.contentdm.oclc.org/cdm/c...9/id/312/rec/1 the weight was close to one of the rockets in the manual.


I fairly sure that the propellant cost is out to lunch and I'm trying to find a fix.


Again thank you both for you help.


Tom Rux


On April 24, 2019 at 8:19 AM Ethan McKinney <xxxxxx@gmail.com> wrote:

These are only the warhead weights and costs: I don't see any calculation of propulsion.

Compared to real-world weapons, the warheads are far too light. As I wrote in my other reply on this subject, 70mm rockets tend to have warheads in the vicinity of 4kg.

Not sure about cost comparison to the real world, but those numbers seem very cheap.

On Tue, Apr 23, 2019, 21:50 David Jaques-Watson < xxxxxx@pcug.org.au> wrote:

Dear Folks –

Tom asked:

> 1. 80 mm and 120 mm rockets

> I have not been able to determine the weight of a single 80 mm or 120 mm

> rocket carrying either a HE or Flechette warhead.

>

> Can anyone please help me find a source for the weight of the rockets?

> Can anyone please help me figure out what they would cost in Traveller?

Striker has the following information:

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Design Sequence 2: CPR Guns

[...]

A. Specifications:

[...]

3. Type: CPR weapons come in several types, differing in their muzzle velocities. These are mortars, low velocity, medium velocity, high velocity, and hyper velocity. Low velocity guns are also referred to as howitzers.

[...]

L. Ammunition: [...] The CPR ammunition price table gives the information needed to determine a round’s price. Multiply the weight of the round by the multiplier for weapon type and the multiplier for ammunition type to determine the rounds price in Cr.

[...]

6. Flechette: These rounds are available at tech level 7+. At tech levels 7-9, they have a penetration of 2; at tech level 10+, they have a penetration of 3. Flechette rounds also have a danger space and a hit DM. Danger space depends on gun type and hit DM depends on bore size, as shown on the flechette table.

(Striker Book 3, pp 11, 12, 14, 15)

 

Design Sequence 9: Tac Missiles

1. Warhead: The warhead may be any low velocity round described in the CPR gun design system. It weighs .05 times the listed weight; the cost multiplier is 4.

(Striker Book 3, p 21)

 

CPR GUN TABLE

Bore   | Wt/ammo | HE    

8 cm   | .66/14  | 13/2/2

8.5 cm | .78/18  | 14/2/2

12 cm  | 2.1/40  | 18/2/3

13 cm  | 2.7/46  | 19/3/3

 

Wt/ammo: The first number is the weight of a high velocity gun in tons. For other types, multiply by the value given on the CPR multiplier table. The second number is the weight of a single round of ammunition in kg.

HE: Contact penetration/burst size/fragmentation penetration. Count down one row for each TL above 6.

(Design Sequence Tables, pp 6,7)

FLECHETTE TABLE

Type          | Danger space

Howitzer      |  5

Med. velocity | 10

[...]

Bore | Hit DM

7-10 | +5

11+  | +6

(Design Sequence Tables, p 9)

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 

With all that out of the way, let’s take a look at what COACC has done.

 

Here are the COACC rockets:

TL | Type      | Size   | Pen | Dmg | Danger

7  | HE        | 80 mm  | 14  | 12  |  20 m

7  | Flechette | 80 mm  |  3  |  3  | 100 m

6  | HE        | 120 mm | 18  | 16  |  25 m

7  | Flechette | 120 mm |  4  |  4  | 150 m

 

The numbers more or less match the Striker rules for tac missile warheads, with a few exceptions.

The HE rockets are almost an exact match for the values given in the CPR GUN TABLE, with the exception being that the 120 mm rocket should have a danger space of 30 m, rather than just 25.

[Workings: Start at the 8 cm (80 mm) row, then count down one row for TL 7. Do not count down for the 120 mm row, as it is stated to be TL 6. Why this was not also specified as TL 7 (which would yield Pen 19) is beyond me.]

The flechettes should both be Pen 2 and no higher as they are both at TL 7. Danger space is a bit more interesting. Since a tac missile is supposed to be based on a _low_ velocity round, this suggests using the Howitzer (50 m) entry on the FLECHETTE TABLE, but the 80 mm rocket’s listed value of 100 m is for a _medium_ velocity round. According the a strict reading of Striker, both rounds should have the same danger space of 50 m, with the larger bore only contributing to the hit DM (which is not used in Megatraveller).

My opinion here is that Terry decided that the flechette rules in Striker make them undifferentiated, bland, and boring – which is a very reasonable point of view. The flechette rules have always had the feel of an afterthought; “yeah, we better throw them in, here’s some basic numbers - DONE!”. It is possible to suggest the numbers are a typo, and the medium velocity numbers were selected incorrectly, but I don’t think so. Instead, I think he has chosen the higher numbers deliberately in order to differentiate the rockets, AND give a nodding acknowledgement to the different Striker hit DMs that otherwise would not be present in a MegaTraveller weapon.

 

 

Ok, so now to answer the original questions: weight and price.

Given that we’ve matched the 80 & 120 mm rounds to the CPR GUN TABLE, we can work from these numbers. The tac missile rules say multiply weight by .05, and price by 4. The CPR ammunition price table uses the formula: weight x weapon type multiplier (Howitzer: x 2) x ammunition multiplier (HE: x 1; flechette: x 5), which is then multiplied by 4 since it’s a tac missile.

[Workings:

     HE 80 mm: Weight = 14 kg * .05 = 0.7 kg; Price = 0.7 kg * 2 * 1 * 4 = Cr5.6

 Fletch 80 mm: Weight = 14 kg * .05 = 0.7 kg; Price = 0.7 kg * 2 * 5 * 4 = Cr28

    HE 120 mm: Weight = 40 kg * .05 =   2 kg; Price =   2 kg * 2 * 1 * 4 = Cr16

Fletch 120 mm: Weight = 40 kg * .05 =   2 kg; Price =   2 kg * 2 * 5 * 4 = Cr80

 

These, therefore, should be the weights and prices:

 

TL | Type      | Size   | Weight | Price

7  | HE        | 80 mm  | 0.7 kg | Cr5.6

7  | Flechette | 80 mm  | 0.7 kg | Cr28

6  | HE        | 120 mm | 2 kg   | Cr16

7  | Flechette | 120 mm | 2 kg   | Cr80

 

Whew!

 

(Anyone wanna check my work???)

-----------------------------------------------------------------------

David "Hyphen" Jaques-Watson ..at.. Beowulf Down (Tavonni/Vilis/SM 1520)

http://www.tip.net.au/~davidjw                    xxxxxx@pcug.org.au

"I file things in historical order, with a hashing algorithm of gravity"

 

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