They did achieve a solution in plenty of time to engage the target at extreme range. Naturally bearing rate would be very low at 35,000 yds and increase as the range came down. It would eventually achieve it's maximum rate at a 90 degree target angle as the aircraft crossed the ship's bow.
Bgile wrote:They did achieve a solution in plenty of time to engage the target at extreme range. Naturally bearing rate would be very low at 35,000 yds and increase as the range came down. It would eventually achieve it's maximum rate at a 90 degree target angle as the aircraft crossed the ship's bow.
If the target was acquired at 14000 yds, instead of 35000, then there wouldn't be time for such a leisurely solution. It is interesting to read the addendum that describes the Mk1A:
as it makes it very clear that the Mk1A mods increased the speed of operation considerably. Another thing of note, is that the Mk1 computer cannot generate an accurate solution above 70deg elevation, so its use against directly attacking DBs would have been minimal.
Yes, to look at that computation time one would think it would be almost impossible for a US ship to shoot down aircraft with heavy flak. It wasn't though, so there must be more to this than meets the eye.
Bgile wrote:Yes, to look at that computation time one would think it would be almost impossible for a US ship to shoot down aircraft with heavy flak. It wasn't though, so there must be more to this than meets the eye.
One of the 1st mods done (mod3), was to increase the maximum range for a solution: http://www.hnsa.org/doc/computermk1/pg383.htm
and I would guess that this was to allow more time to generate a solution.
The example given previously is very odd, in that the radar ranging system should have had a very good estimate of target direction, range and speed, and maybe even height, and you would think that the computer would have been given this info to set the initial values to speed generation of a solution. Another thing of note is that the Mk1A addendum states:
Putting in range rate control corrections. The description given under this heading OP 1064 (pages 54 and 65) is applicable to Computer Mk 1A with the following exceptions
In paragraph two of page 54 it is stated that range is received only intermittently. Computer Mk IA receives continuous inputs of range whenever the radar equipment which the gun fire control system is utilized for ranging.
From the description in the "80 second" example I don't think radar was being used at all. I think radar would tend to increase the initial tracking range.
Bgile wrote:From the description in the "80 second" example I don't think radar was being used at all. I think radar would tend to increase the initial tracking range.
Yes, initial contact was by radar, but the detailed description of tracking makes it look very much like optical ranges were being used, and there is no mention of radar being a part of that process.
Bgile wrote:Yes, initial contact was by radar, but the detailed description of tracking makes it look very much like optical ranges were being used, and there is no mention of radar being a part of that process.
True, but the initial inputs of speed, range and bearing were taken from radar and these proved to be quite accurate, and it still took 80sec to reach a solution.
Here is why I think USN heavy AA was effective against aircraft attacking ships:
The director solution was in the ballpark from the very beginning, it just took a long time to get a really accurate solution. A really accurate solution wasn't in fact possible for long anyway because the aircraft would maneuver and throw it off.
The 5" battery would open fire once the aircraft was in range, irrespective of a "good" solution.
There were various inaccuracies in the system, including but not limited to shell men not loading at exactly the same rate, so dead time being different from one guy to another and even a small amount from shell to shell for a good loader.
Even with all these inaccuracies, you are still shooting in the close vicinity of the target; just not close enough to hit it if the inaccurate director solution is applied "perfectly". But it isn't applied perfectly, because of all these little inaccuracies in the system. Now consider that there are a large number of 5" guns firing, and a lot of shells going out to the vicinity of the target. Once in a while one of those shells goes off close enough to shoot down an aircraft.
I suspect the above explains a significant percentage of kills by 5" guns. Inefficient? Yes. Thousands of rounds expended for each enemy aircraft destroyed. But, the ammunition was there to be expended, and it worked.
Bgile wrote:Here is why I think USN heavy AA was effective against aircraft attacking ships:
That's pretty much my thinking, as well. It means that the average solution quality varied considerably from the "perfect" solution possible by the Mk37GFCS, and I suspect that this was true for most tachymetric, linear rate, systems. It makes it difficult to determine the cost effectiveness of these complex computers.
