Search found 172 matches

by RobertsonN
Tue May 21, 2019 9:39 pm
Forum: Bismarck General Discussion
Topic: On the Origins of Scaling
Replies: 13
Views: 546

Re: On the Origins of Scaling

It is often helpful in developing one's own ideas to talk to other people about them as here. Looking at support for the ideas I am putting forward in Gkdos100: For the 38 cm APC sees against KC n/A that the curves are very close together at 90 deg obliquity (normal) are very close together (a diffe...
by RobertsonN
Tue May 21, 2019 8:27 pm
Forum: Bismarck General Discussion
Topic: On the Origins of Scaling
Replies: 13
Views: 546

Re: On the Origins of Scaling

The scaling effect in going from 15 in to 16 in is likely to be distinctly less than the difference in impact velocity, although it depends a bit on what the range is as the 15 in will slow down more than the 16 in as range increases, reducing that 100 m/s difference. In this example the 15 in proba...
by RobertsonN
Tue May 21, 2019 6:24 pm
Forum: Bismarck General Discussion
Topic: On the Origins of Scaling
Replies: 13
Views: 546

Re: On the Origins of Scaling

Could you give a reference for that opinion you have read? I have never come across anything suggesting that bigger plugs were in general thrown out of thick KC plates by large calibre shells than was the case for smaller shells against thinner armor. IIRC in US tests of 14 in APC against ultrathick...
by RobertsonN
Fri May 17, 2019 10:20 pm
Forum: Bismarck General Discussion
Topic: On the Origins of Scaling
Replies: 13
Views: 546

Re: On the Origins of Scaling

Normal Attack and Scaling At normal attack it is axial forces causing compressive failure that endanger the shell including shock-induced shatter and inertia-induced shatter sometimes called secondary shatter as it occurs later than shock-induced shatter provided that it has not happened. With shoc...
by RobertsonN
Fri May 17, 2019 9:55 pm
Forum: Bismarck General Discussion
Topic: On the Origins of Scaling
Replies: 13
Views: 546

Angle Attack: Breakage Mechanisms and Scaling On p. 93 of the USNMTE Gercke wrote: 'Because of the stresses caused by the transverse forces the projectile must be given a hardness gradient from the nose to the base in order to withstand them. In order to limit the value of M1 [the moment of force c...
by RobertsonN
Fri May 17, 2019 9:11 pm
Forum: Bismarck General Discussion
Topic: On the Origins of Scaling
Replies: 13
Views: 546

On the Origins of Scaling

Summary Scaling is the feature of armor penetration curves which show a reduced critical velocity with increase in calibre for given T/D (plate thickness/shell calibre) ratio. Scaling is a feature of the penetration curves given in Gkdos100. Nathan Okun attributed this scaling to a reduced ability ...
by RobertsonN
Tue May 07, 2019 7:39 pm
Forum: Bismarck General Discussion
Topic: Some questions regarding Bismarck's armor scheme
Replies: 17
Views: 912

Re: Some questions regarding Bismarck's armor scheme

It is perhaps useful to study, as in Figs 12 and 13 of the paper by Hoyer (which appears elsewhere on this site), the curves showing the critical velocities needed for penetration and that of the projectile terminal velocity with range and inclination. If the critical velocity is below the terminal...
by RobertsonN
Sun May 05, 2019 11:21 pm
Forum: Bismarck General Discussion
Topic: Some questions regarding Bismarck's armor scheme
Replies: 17
Views: 912

Re: Some questions regarding Bismarck's armor scheme

It is perhaps useful to study, as in Figs 12 and 13 of the paper by Hoyer (which appears elsewhere on this site), the curves showing the critical velocities needed for penetration and that of the projectile terminal velocity with range and inclination. If the critical velocity is below the terminal ...
by RobertsonN
Sun May 05, 2019 7:21 pm
Forum: Bismarck General Discussion
Topic: Bismarck construction flaws
Replies: 396
Views: 141177

Re: Bismarck construction flaws

95mm is more incline to bend instead of spalling I think. to be precise MAD over magazines 100 mm (scarps 120 mm) Wh (Zeichnung Panzerabwicklung „Schlachtschiff F“ gültig für Panzerdicken, im Laufe des Baues geändert, Geheime Kommandosache) German homogenous armor plates possibly from from Tirpitz ...
by RobertsonN
Sun May 05, 2019 4:16 pm
Forum: Bismarck General Discussion
Topic: Some questions regarding Bismarck's armor scheme
Replies: 17
Views: 912

Re: Some questions regarding Bismarck's armor scheme

The mention of the paper by Hoyer has drawn my attention to something I had overlooked before. Namely, I had thought that the curves Vg in Figs 12 and 13 were curves of terminal velocity (from its shape) rather than of the velocity at which the shell fractures on impact. Also generally in GKdos 100 ...
by RobertsonN
Fri May 03, 2019 7:56 pm
Forum: Bismarck General Discussion
Topic: Some questions regarding Bismarck's armor scheme
Replies: 17
Views: 912

Re: Some questions regarding Bismarck's armor scheme

The question about AON battleships in the RN. I think no one would dispute that Nelson and Rodney were armored on the AON principle. However, in the KGVs there was at least as much armor before and aft of the citadel as in traditional British designs. The KGVs also raised the armor deck by one deck ...
by RobertsonN
Fri May 03, 2019 7:33 pm
Forum: Bismarck General Discussion
Topic: Some questions regarding Bismarck's armor scheme
Replies: 17
Views: 912

Re: Some questions regarding Bismarck's armor scheme

The point about the 220 mm thick barbette armor on Bismarck. This is indeed low for the period in question, although well up on WW1 ships. This armor was KC. No shell could strike it without having first gone through the upper belt or the upper deck. In both cases the shell would be decapped. On hit...
by RobertsonN
Fri May 03, 2019 6:43 pm
Forum: Bismarck General Discussion
Topic: Some questions regarding Bismarck's armor scheme
Replies: 17
Views: 912

Re: Some questions regarding Bismarck's armor scheme

One point about the overall protection scheme used by the Germans is that it reduced the chances of hits penetrating the citadel by effectively reducing the target area. By such means the chances of damaging hits at ranges where the ship's main armor could be penetrated could be reduced. While a shi...
by RobertsonN
Wed Feb 27, 2019 8:05 pm
Forum: Naval Weapons
Topic: Shell hits v armour
Replies: 4
Views: 990

Re: Shell hits v armour

Paul, I do not know if target motion at the time of impact was a significant factor in armor penetration, but this question seems to have escaped detailed analysis up to now. Often, tthe advantage of light was decisive, such as at Colonel. This advantage involved chance, that of the relative locatio...
by RobertsonN
Mon Feb 25, 2019 7:55 pm
Forum: Naval Weapons
Topic: Shell hits v armour
Replies: 4
Views: 990

Re: Shell hits v armour

I think you are correct in saying that chance could play a big role in naval engagements. The form of the hull, pitch, roll and yaw all affect the overall angle of incidence. The striking velocity will depend on the nominal muzzle velocity, state of wear of the barrel, charge temperature, relative v...