Search found 4398 matches

by dunmunro
Wed Mar 13, 2024 10:19 pm
Forum: Bismarck General Discussion
Topic: Raeder report to Hitler about Bismarck operation
Replies: 14
Views: 5608

Re: Raeder report to Hitler about Bismarck operation

Lutjens view, as overuled by Raeder, was to wait until Autumn, when Tirpitz might be available. Tanker Wiessenburg was stationed by Jan Mayen to provide full refuelling for both ships immediately prior to breakout. The breakout would be better with longer nights rather than shorter, which would fav...
by dunmunro
Wed Mar 13, 2024 4:40 pm
Forum: Bismarck General Discussion
Topic: Raeder report to Hitler about Bismarck operation
Replies: 14
Views: 5608

Re: Raeder report to Hitler about Bismarck operation

What is interesting about the report as detailed in the first post are the questions that the Fuhrer DIDN'T ask. Lutjens view was to delay Rheinubung until either Tirpitz was ready or to the availability of Scharnhorst and Gneisenau to break out of the Biscay ports back into the Atlantic. That is a...
by dunmunro
Wed Feb 28, 2024 4:01 am
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

[ Take a look at the Kerrison Predictor: https://en.wikipedia.org/wiki/Kerrison_Predictor In your example the two predicted target locations would vary enough that no hits could be expected on the further target unless target's actual course was modelled accurately. Didn´t know that device, thanks ...
by dunmunro
Tue Feb 27, 2024 5:15 pm
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

1)The COFAS has a reticle for eye-shooting aim off. The GRU sight required that the target be kept centred in the crosshair to allow the gyro to compute the target rate. 2) With continuous radar ranging the GRUB (computer could (and must) calculate true target motion otherwise radar ranging would a...
by dunmunro
Tue Feb 27, 2024 4:58 pm
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

Tachymetric analog computers could predict target location accurately given accurate inputs; that was the whole point of it all. Where the computers failed was when the TOF was too long and the target's predicted location would no longer match it's actual location, due to target manoeuvring. Look a...
by dunmunro
Tue Feb 27, 2024 1:46 am
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

Yes, I f you have a continuous range to the target , via radar, then it's possible to accurately predict the target's location at the end of the projectile's TOF, but only if target motion is accurately modeled. I think that that is beyond the possibilities of the technology of the day. Somehow you...
by dunmunro
Mon Feb 26, 2024 5:46 pm
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

2) With continuous radar ranging the GRUB (computer could (and must) calculate true target motion otherwise radar ranging would actually make predicted target position more inaccurate, So you mean that if in the second sweep the radar detects the plane closer (or farther) to the ship the computer w...
by dunmunro
Sat Feb 24, 2024 6:12 pm
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

Hi! In the Mk14-Mk51 the lead is applied by a moving reticle, the telescope/sight does not move beyond what is needed to follow the target. It can be that in the MkIV the lead is applied by the calculator by leading the guns respect to the sights. A further comment. These gyro-based systems did not...
by dunmunro
Thu Feb 15, 2024 4:50 pm
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

A torpedo bomber would not be flying directly at the ship. There was quite a lot of lead involved. Yes some deflection, but nothing like that required to engage the same aircraft attacking a different ship. I don't thing a low deflection shot is easy... most aircrafts' side profile is about 5 to 10...
by dunmunro
Thu Feb 15, 2024 4:38 pm
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

1) The layer and trainer's sights were aligned with the COFAS so it would be obvious to the CO and the layer and trainer if they were following the wrong target. 2) In later models the COFAS was linked to power control to allow the CO to track the target via the COFAS to ensure that everyone was fo...
by dunmunro
Sun Feb 11, 2024 9:00 pm
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

Well, a circular screen of an HVT would have the screening ships often less than 2,500 yds apart, so well within 2500 yds and attacker would often be trying to fly between the screening ships. The Pom-poms can't open fire if screening ships would be hit. IIRC, the screens were meant to be beyond th...
by dunmunro
Sun Feb 11, 2024 3:21 am
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

A torpedo bomber would not be flying directly at the ship. There was quite a lot of lead involved. Yes some deflection, but nothing like that required to engage the same aircraft attacking a different ship. True, but of course you would be trying to do that as well. True, but the pom-pom's SD fuze ...
by dunmunro
Sat Feb 10, 2024 6:23 pm
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

Steve Crandell wrote: Sat Feb 10, 2024 5:18 pm A torpedo bomber would not be flying directly at the ship. There was quite a lot of lead involved.
Yes some deflection, but nothing like that required to engage the same aircraft attacking a different ship.
by dunmunro
Sat Feb 10, 2024 11:04 am
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

Regardless, the Mk IV director need the crew of 8 + radar crew to work in unison, and there will definitely be delays such as 1. trainer and layer to recognise the target selected by CO 2. GRU operator to line up with target and followers to put in the rates 3. Range follower to input range, either...
by dunmunro
Tue Feb 06, 2024 5:07 pm
Forum: Naval Weapons
Topic: Pom pom with director Mk IV vs Bofors 40mm with Mk 51
Replies: 36
Views: 2650

Re: Pom pom with director Mk IV vs Bofors 40mm with Mk 51

Illustrious and Victorious were originally fitted with Mk III directors. Pom-pom mounts began to be fitted with USN Mk 14 gyro gunsights, probably in 1942, but I don't know the status of the mounts used during PEDESTAL. The one man joystick control was engineered by the Mediterranean Fleet and then...