Estimating Range With Gun Sight Triangles: Home Experiments

[Mr. Tittles]

So, I disagree that what is being discussed is a RANGEFINDER. Rather, I think the reticle is part of the SIGHT. Because it is well-designed, it can assist in RANGEFINDING. So, perhaps we're both being pedantic.

Well I partly agree. That is, you are certainly being pedantic. The triangle is both used for estimating range (while not a digital readout, its sure nice to have) and the actual pointing of the weapon itself. But not at the same time or even not without positioning the triangle differently. Supposedly the Germans aimed at the bottom of the target vehcile. The triangle had to have its base lined up with the target vehicle. In any case, is it really that big a deal to you? Ill drop it if you do and I agree that it probably needs attention for future projects.

I think there are other uses for the triangle. It can help in finding the center of the target. Especially ones at longer ranges where the width of the triangle is larger than the base of the target vehcile.

[ September 03, 2004, 01:32 PM: Message edited by: Mr. Tittles ]

[FM Paul Heinrik]

At what point does it cease being a grognard topic and simply turns into a nerd topic?

[danielh]

Rexford,

Great work !!! Thanks alot !!

Btw. I recently rechecked the Pantherfibel, and i'm still firmly convinced, that on the hitladder PzGr-shot only climbs half a "Strich" for every 100m range added out to around 1200m, recheck page 20 and 22 !

Text from page 22:

"Bei "Panzer" ändert es sich wieder. Die Schüsse fliegen flach und nieder, und einen halben Strich nur klettern sie höher bei je 100 Metern..."

My free translation:

"On using "Panzergranate" however it changes again. The shots now fly flat and low and only half a "Strich" do they climb at every 100 meters increase in range setting"

The text on page 22 continues the rule for "Nabelvisier" on page 21 which refers to explosive grenades. The upper picture on page 22 shows the hitladder for explosive, the bigger one below the one for PzGr.

Keep up the splendid work !

Greets

Daniel

[Michael Dorosh]

Originally posted by rexford:

British trials during WW II showed that the average crew was capable of estimating range to a target tank with an average error of about 20%, when only the eyes were used. The distribution was bell shaped with a standard deviation of 25%.

To see whether those German gun sight triangles would improve things and to examine the ins and outs of the triangles, two trials were conducted.

You made it sound like this was an actual trial during the war. I take it from the rest of the conversation, this was actually you?

[rexford]

Did some additional experiments yesterday in the empty gym (it's mine, all mine!), and put together the following write-up which is a little more concise:

Experiments with a simulated German gun sight of 5x magnification and a scale model T34 resulted in the following range estimation statistics under ideal conditions (gunner able to separate front and side views of target, target fully exposed in the open):

350m to 750m Target Distance

============================

Average range estimate error of 10.9% based on random selection of 70 cases using center of curve and standard deviation

Bell shaped curve centered at a 0.58% error with a standard deviation of 13.54%

34 cases

750m to 1000m Target Distance

=============================

Average range estimate error of 9.9% based on random selection of 70 cases using center of curve and standard deviation

Bell shaped curve centered at a -6.54% error with a standard deviation of 12.03%

48 cases

1000m to 1500m Target Distance

==============================

Average range estimate error of 7.8% based on random selection of 70 cases using center of curve and standard deviation

Bell shaped curve centered at a -1.77% error with a standard deviation of 10.56%

31 cases

1500m to 2000m Target Distance

==============================

Average range estimate error of 8.9% based on random selectionof 70 cases using center of curve and standard deviation

Bell shaped curve centered at a -8.17% error with a standard deviation of 10.17%

36 cases

Compared to the typical British gunner who was found to average a 20% range estimate error during firing trials, use of the German gun sight triangles would result in a significantly lower first shot ranging error.

The interesting thing about a 5x magnification gun sight is that a 2000m target presents the same visual view as a 400m target to the unaided eye in terms of size. As long as the German gunner could make out the front of the tank target from the side (which seems to be possible under some conditions with a 400m range to the "naked eye"), the ability to estimate range would be close to what I came up with.

The problem with separating side and front armor is that at small hull angles to the sighter, such as 7 degrees, a 3m front width T34 would show quite a bit of the side armor (6m length) and the perceived width of front and side armor would be:

3m x cosine (7 degrees) + 6m x sine (7 degrees) = 3.7m, which right off the bat throws the range estimate off by about 20%.

[ September 05, 2004, 07:28 AM: Message edited by: rexford ]

[rexford]

Originally posted by Michael Dorosh:

</font><blockquote>quote:</font><hr />Originally posted by rexford:

British trials during WW II showed that the average crew was capable of estimating range to a target tank with an average error of about 20%, when only the eyes were used. The distribution was bell shaped with a standard deviation of 25%.

To see whether those German gun sight triangles would improve things and to examine the ins and outs of the triangles, two trials were conducted.

You made it sound like this was an actual trial during the war. I take it from the rest of the conversation, this was actually you? </font>

[rexford]

Originally posted by danielh:

Rexford,

Great work !!! Thanks alot !!

Btw. I recently rechecked the Pantherfibel, and i'm still firmly convinced, that on the hitladder PzGr-shot only climbs half a "Strich" for every 100m range added out to around 1200m, recheck page 20 and 22 !

Text from page 22:

"Bei "Panzer" ändert es sich wieder. Die Schüsse fliegen flach und nieder, und einen halben Strich nur klettern sie höher bei je 100 Metern..."

My free translation:

"On using "Panzergranate" however it changes again. The shots now fly flat and low and only half a "Strich" do they climb at every 100 meters increase in range setting"

The text on page 22 continues the rule for "Nabelvisier" on page 21 which refers to explosive grenades. The upper picture on page 22 shows the hitladder for explosive, the bigger one below the one for PzGr.

Keep up the splendid work !

Greets

Daniel

The Tiger and Panther Fibels show that the range estimate is adjusted by adding 100m times half the perceived height in mils. I think this is the same thing you are saying.

If the perceived target height is 3 mils, the range setting is adjusted by adding 3 mils x 1/2 x 100m or 150m to the initial range estimate.

[Mr. Tittles]

Heres what German binocs probably looked like.

[lorrin]

Originally posted by Mr. Tittles:

Heres what German binocs probably looked like.

Thanks for photo and drawing.

Do we know for sure that German tank commander binocs had mil markings (lat and vert) on them: it may have been discussed before but I don't recollect the answer right now.

[lorrin]

Originally posted by Mr. Tittles:

Heres what German binocs probably looked like.

Thanks for photo and drawing.

Do we know for sure that German tank commander binocs had mil markings (lat and vert) on them: it may have been discussed before but I don't recollect the answer right now.

[Mr. Tittles]

A few sources mention them.

[lorrin]

Originally posted by Mr. Tittles:

A few sources mention them.

Thanks, good info.