Panther Fibel Discussion of Range Estimation

[danielh]

Hello Mr. Tittles and Rexford,

I've a question, which you could maybe answer.

I recently read in the Spielberger / Doyle /Jentz Book "Begleitwagen Panzerkampfwagen IV" (Pz IV)

There on page 227 a so called "Panzerbeobachtungswagen IV" -> (Tankobservationvehicle IV) is mentioned. Being an ordinary Pz IV J with additional radios but and this is the important one, with the same Cupola as being used in late StuG IIIs. In the text accompanying the picture drawing on page 226 it is mentioned, that using the StuG-Cupola it was possible to use the SF 14 Z (Scissors Periscope) also in buttoned position (looking through the armored glasses of the Cupola). What do you say to that ? How much would the "brightness" and picture quality in general be affected by the thick armorglass ? Obviously the SF could not be used with ordinary PzIV's while being buttoned. Were they used for Forward Artillery Observation or what ?

Greets

Daniel

[Mr. Tittles]

This pic clearly shows the stereoscopic teddy bear in its splayed out employment. Notice the StuG III cupula.

I would say they were FO vehciles. The scope could also be raised above the cupula rim and the TC head could be below the cupola height. Similar to the pic posted earlier of the StuG TC using SF scopes (from afv interoir website).

Anyone speak Polish?

http://klub.chip.pl/krzemek/pzkpfw_iv/pz4_inne.htm

[ August 20, 2004, 05:02 PM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

http://www.germanmilitaria.com/Heer/photos/H00349.html

A website with pics of SF14Z Gi (These are definetly WWII items with the grid reticle).

Interestingly, the author make some mistakes. He even calls the 1/6400 number a serial number!

He makes no mention of them being used as range measurement instruments.

Its clear to me that the knob on the side (black knob) is used to adjust for bubble level and not rangefinding. Each eyepiece has adjustment for focus just like ordinary binos. There is no other adjustment that deals with scope except the round knob with locking device that is on the front of the device.

Just how these could actually be used is a mystery.

[Andreas]

According to my grandfather, who I asked about this yesterday, the scissors scope could not be used for rangefinding on the hoof. He was very insistent about this, and I asked him a number of times in a round-about way.

You could use it for range-estimation when you had prepared adequately:

a) you needed to know exactly where you are on a map

you needed at least two independent measurement points, called "Brechpunkte" (break points), to which range had to be accurately measured before from the location of the scissors scope

When a) and were present, you could calculate range, and height (of air bursts)

When these were not present, you could not.

The way they estimated range in counter-battery standard procedure was relatively simple. They did not. Instead they used triangulation. Measure flash from three different points. Draw lines. Where the lines meet on the map, the enemy gun stands. No range estimation in this process, only direction finding.

The main benefits of the scissors, according to him, were that it was a very high quality bino, and it could be used from behind cover with minimal exposure of the scope, and none of the viewer. Another benefit was that it had a firm mounting.

[Mr. Tittles]

The scissor scopes go back to the turn of the century. Earlier versions did not have the range finding capability supposedly. This was something that was developed later. Your website does show a pic looking through a scissor scope and it does have the grid present. I would have assumed he would have a current version and not some left over device. These would have been SF14Z Gi.

Did he comment on needing to splay them out then? Did you ask how they were adjusted, etc?

He seems to be assuming that you are inquiring about using them to call in artillery? I say that because he mentions needing to know where you are on the map. For firing direct, that would not matter.

He seems to be commenting that if you have two known ranges to yourself, you could then use the grid to approximate the distance/height?

So for a jagdpanzer that was in a defensive position, and it had previously determined distance locations (crossroads, bridge, etc), then the device would be able to use its superior stereoscopic viewing to determine relationships between those points?

It must have been good enough to approximate airbursts height?

[Andreas]

I would assume he had a current version as well. Both of his B-Abt. were 2. Welle formations (B26 and B30), so they would have gotten decent equipment and training on this, I would assume. But assumptions are the mother of all F-ups, as we all know, and they had to make do with French lMGs.

For a vehicle in a chosen position, I believe you could make it work, with the appropriate training of the crew, and some time before the proverbial hits the fan. You also need decent LOS conditions, of course.

I assume height estimation would work because they would be told the range to target from the Auswertestelle (~FDC), before firing the ranging shot, and they could then use the grid (that was apparently what the grid was used for).

My grandfather would really only know about using them to fire for artillery. That was what he did, and he never told me he used them for other things. He said they did not splay them out completely, usually, but it is possible he did not understand the question completely. I asked how they were adjusted, and I am afraid I did not get all of the answer. I'll try that again tomorrow or Wednesday.

But yes to both your questions - range estimation with two known ranges perfectly possible, and good to estimate heights once you knew range.

As a side-note, there was apparently a very small stereoscopic range-finder, or something that looks like it, that was handed out to mortar teams and maybe HMG teams. I have a picture of a German soldier of an 81mm mortar team using one in the Baltics in '41.

Edit because I think I got my Wellen wrong.

[ August 23, 2004, 11:39 AM: Message edited by: Andreas ]

[Mr. Tittles]

All's Wellen that ends Wellen...

[rexford]

On German ships the stereoscopic readers were assigned psychologists and trainers to keep their eyes and brains in best working order. Although the accuracy of the stereoscopic range finder was great during naval combat at many miles distance getting the best one could was a necessity.

A 3m long stereoscopic rangefinder was capable of fantastic accuracy. If the magnification was 25x, the accuracy at 2000m would be plus or minus 2.6m!

The following site has an article on stereoscopic rangefinder history, use and accuracy:

http://www.warships1.com/index_tech/tech-078.htm

Of interest to WW II tank fans is the write-up on "blue coating" which made the image brighter and clearer. Sounds similar to the U.S. reports that captured German gun sights were better in reduced light than American and gave better target outline.

[rexford]

Using the equation presented in the rangefinder article noted in the previous post this thread, the German TF 14 stereoscopic rangefinder would be capable of the following accuracy (magnification of 14, base length of 0.9m):

1000m: 4m (12m for tripled error may be practical error)

1500m: 9m (27m practical error)

2000m: 16m (48m practical error)

2500m: 24m (72m practical error)

3000m: 35m (105m practical error)

The Spielberger book on Panther tanks suggests that the practical error would be three times the calculated figure, which appears to consider human errors and day to day variations in ability.

If a Nashorn were firing at a target 2000m and the range estimate were based on a stereoscopic rangefinder, the range estimate would be 2048m and the first round would, on average, be 1.61m above the target bottom for a hit if all of the target were exposed (German practice was to aim at the bottom of the perceived target height and add range to bring the shot up on the target).

At 3000m, the initial range estimate would be 3105m and the first shot would be, on average, 3.45m above the target bottom for a miss. However, T34's and Shermans would be about 2m to 2.2m high (hull bottom to turret top) so a minor correction would be needed for a second shot hit (shot would overfly target turret by less than 1.5m).

For instance, if the Nashorn crew estimated the second shot range as 3000m (down 100m), the round would pass by the target 1.11m above target bottom for a hit (using the average trajectory).

Due to round to round random scatter, individual shots would vary from the average trajectory.

It appears that Nashorn were equipped with the TF 14 scissor scope, although use of them might require that the device be folded so the arms were horizontal and then held above the vehicle armor.

While the TF 14 might be capable of 105m practical errors at 3000m, a trained commander using his eyes would have an average error of above plus or minus 20% for 600m.

A gunner using the triangles on the gun sight, which denote 2 or 4 mil heights or widths, would see a 3m wide T34 as 1 mil width at 3000m, or a 2m high T34 as 0.67 mils.

The problem with the triangle range estimation is that a 3m wide T34 might be at a 10 degree angle to the viewer, which would make the width appear to be 4m due to viewing of the front and side armor. With 5x magnification, the Nashorn gunner sight would make the T34 seem like it was 600m away to the unaided eye, too far to separate front and side armor widths for the image.

The TF 14 magnification factor of 14 would make the T34 at 3000m seem to be 214m away if viewed with the eyes alone, which might make estimates of frontal width alone possible and eliminate the addition of side armor.

If the Nashorn gunner sees a 4m wide T34 at 3000m, the perceived width on the gun sight would be 1.3 mils, suggesting a range of about 2300m for a standard frontal width of 3m. The triangle method would not be close.

If the gunner also used the perceived height of the T34, seeing a 2m height for a T34 M43 at 3000m as 0.67 mils, the range estimate could be close to 3000m if the entire vehicle were in view and the lower area was not blocked by ground curvature or vegetation.

[Mr. Tittles]

PzBeobWg. Used by artillary observers, this one is mounted on a Panther chassis, note the cupola. The dummy gun is quite obvious.

This OP tank was used by FOO’s (Forward Observation Officers), for directing artillery fire. Unlike the command tank, it required more major modification, and only 40 were built.

The first prototype was built on the Ausf D chassis in mid-1943. Production began early in 1944and from then on, the remainder were mounted on Ausf A and G chassis. The hulls were as the standard tank, with the modifications being made to the turret.

The main gun was removed, this being replaced with a dummy gun made of sheet metal, which was bolted to the front of the turret. Instead of the normal co-axial MG 34, there was a ball mount for the same weapon. This had a traverse of 5° left and right, and elevation range from -10° to +15°.

For communications, the vehicle carried three radios. A FuG8, FuG4 and a Funksprechgerät f. There was also a range of observation equipment with which to direct artillery fire. In the turret roof, there was a TBF2 periscope in a ball mounting with 360° traverse. In an adjustable bracket in front of the commanders cupola was a SF142 scissors periscope. This bracket was also used for the TSR1 spotting telescope. On the front wall of the turret was a Zeiss built EM1.25m range finder. There were slots with hinged armoured covers in the front of the turret. Finally, there was a KZF2 telescopic gun sight. In front of the commander, there was a plotting board. This allowed him to accurately plot the position of a target, before directing the guns to fire. There were also several dials in the turret, which assisted the commander with bearings for the target. As these vehicles were so rear, they only went to the premier Pz Div’s, both army and SS. They were used to direct the self-propelled artillery batteries using Wespe and Hummel SP guns.

There were four crewmembers in these vehicles, and the weight was reduced to 41.6 tonnes.

[ August 31, 2004, 02:21 PM: Message edited by: Mr. Tittles ]