Search found 726 matches

by Thorsten Wahl
Mon Sep 02, 2019 9:03 am
Forum: Naval Technology
Topic: Discuss
Replies: 1
Views: 147

Re: Discuss

by Thorsten Wahl
Mon Aug 26, 2019 4:16 pm
Forum: Bismarck General Discussion
Topic: FYI: meaning of the notation of the draft measurements during Bismarck’s trial runs, fall 1940
Replies: 25
Views: 642

Re: FYI: meaning of the notation of the draft measurements during Bismarck’s trial runs, fall 1940

One thing being ignored here, or at least minimized, is the rather dramatic effect of propeller efficiency. Especially if one is running close to the cavitation limit, which Bismarck would almost certainly have been during high-speed trials, even a small defect in blade geometry can affect the spee...
by Thorsten Wahl
Mon Aug 26, 2019 3:50 pm
Forum: Bismarck General Discussion
Topic: Battleship Bismarck: A Design and Operational History
Replies: 59
Views: 8857

Re: Battleship Bismarck: A Design and Operational History

All distances in page 211 map look too great to be correct (BS open fire is reported by Lutjens at 20800 meters while is 21500 in the map at pag.211 An aside note: 20.800 m distance seem the calculated distance for firecontrol purposes. The Germans use true gun distance as distance when discussing ...
by Thorsten Wahl
Wed Aug 14, 2019 8:33 am
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: 3-shaft propulsion

i made a spreadsheet based on development of RPM to achieve certain speed normalised with RPM required to achieve 15 kn beeing 100% -Data according source mentioned -For the US data i used the average RPM number from the FTP 218 spreadsheets -I interpolated RPM numbers for uneven speeds for Howe -Th...
by Thorsten Wahl
Wed Aug 14, 2019 8:19 am
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: 3-shaft propulsion

the advantage was denominated by the Germans 3 Welleneffiziens1.jpg with ~48% screw-efficiency compared to ~42% screw-efficiency for a 4 screw ship. As i wrote earlier this advantage is in line with british publications to the same theme in "The engineeer" That means a 3 screw ship requires about 6 ...
by Thorsten Wahl
Fri Aug 09, 2019 12:27 pm
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: 3-shaft propulsion

KGV recorded .715 lb/shp during trials and 111700shp = 35.65 tons/hr. Just for the record, where is this data from? Regards The Design and Construction of British Warships, 1939-1945: The Official Records : Major Surface Warships by DK Brown. Hello Duncan did DK Brown mentioned the heating value/ d...
by Thorsten Wahl
Thu Aug 08, 2019 8:41 am
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: 3-shaft propulsion

some data for Gneisenau
Gneisenau Fahrleistunga.jpg
Gneisenau Fahrleistunga.jpg (23.45 KiB) Viewed 316 times
by Thorsten Wahl
Thu Aug 08, 2019 7:53 am
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: 3-shaft propulsion

please dont derail this thread.
by Thorsten Wahl
Wed Aug 07, 2019 1:41 pm
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: 3-shaft propulsion

many thanks,
difference appears negligible to me
additionally the power output of the turbines and the power output of M1-machinery for different RPM comparing Fahrtabellen and turbinedata is seemingly in very good agreement.
by Thorsten Wahl
Wed Aug 07, 2019 9:53 am
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: 3-shaft propulsion

@Herr Nilsson, the 270 RPM value for Bismarck/Tirpitz refers -coincidentally- to a speed of about 30,2 kn of the Bismarck Meilenfahrt? is this correct? additional edit: according to MDV 371 or the Oberbaurat Krux Memo the Marine Wagner Boiler consumes 3,950 kg fuel oil (at äußerste Last) to produce ...
by Thorsten Wahl
Tue Aug 06, 2019 7:39 pm
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: 3-shaft propulsion

Scharnhorst's and Tirpitz' turbines were of similar design, but Bismarck's was very different. According their manuals Scharnhorst and Tirpitz had a very similar (almost identical) steam consumption per SHP You meant the consumption drawings in Kriegserfahrungen...Oberbaurat Krux? Power RPM ....ste...
by Thorsten Wahl
Tue Aug 06, 2019 1:25 pm
Forum: Bismarck General Discussion
Topic: British postwar tests on armor
Replies: 83
Views: 3385

Re: British postwar tests on armor

ballistic test of a PC 500 Bomb vs 120 mm Wotan hart impact Speed 186 m/s simulated divebomb drop from 1300 m height with aircraft speed 500 km/h PC 500d.jpg the casings of german PC and PD (armor piercingt bombs) bomb were sufficent to survive impacts at least from throwing heights of 4000 m comple...
by Thorsten Wahl
Tue Aug 06, 2019 6:46 am
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: 3-shaft propulsion

Howe_endurance1.jpg
Howe_endurance1.jpg (33.78 KiB) Viewed 310 times
by Thorsten Wahl
Mon Aug 05, 2019 2:08 pm
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: 3-shaft propulsion

In terms of propeller design is concerned, overall efficiency tends to go up as one moves towards fewer and larger propellers with larger numbers of blades rotating at slower speeds. That is another question I have, and already mentioned, why did they go to 270 rpm propellers when other naval power...
by Thorsten Wahl
Mon Aug 05, 2019 1:45 pm
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2533

Re: Battleship Bismarck: A Design and Operational History

Hello everybody, What was improved in Bismarck's boilers/machinery vs Scharnhorst's ? Wasn't the Bismarck propulsion plant (including the boilers) basically the same as Scharnhorst's ? Whitley mentions a pressure of 58 kg/cm2 @ 450° for Scharnhorst too... Bye, Alberto Bismarcks machinery was more s...