Recommended optics modification for SU-76

[Amizaur]

Beautiful !!! Excellent photo !!

So there is a 2mil "gap" in the arrowhead (the vertical line not connecting the aiming V mark) just like in TSh-1x gunsights.

Well it actually looks THE SAME as PG-1 so far (you say it's a PG but not a PG-1). Because after close examination of your first PG-1 photo

(first reticle photo in the thread, smaller one)

you can see that the vertical line indeed doesn't go all the way up to the arrow head, but stops 2 mils short - like on this photo.

Maybe rather the drawings from manuals are not precise regarding to this detail. On the other hands it's precise enough to show other small details and a correct scaling...

edit: after even closer examination, reticle from your last photo seem identical than on my drawing (from 152mm D-1 howizter manual) but different from your drawing (from 85mm D-44 manual) LOL because on D-44 the gap in the center of the cross looks like 2 mil wide (1mil each side from center) and not 4mil wide like on D-1 drawing. But height of the gap is always the same. Also on all the drawings with exeption of D-44 and now clearly on the photo seem that the gap, from the center, is exactly half of the distance.

That would be 2.5 mil and not 2 mil as I judged from D-1 drawing (seemed a bit less than half, and 2.5 mil seemed very strange width to mark on a sight for me...).

One possibility is that the side marks are 4 mils apart, not 5 - but in D-1 manual it is clearly said they are 5 mils and also calculation of the (side marks/sight FOV) would not fit if it was 32mils instead of 40 . Or the central gap is indeed 2x2.5 mil which gives 5 mils which is a round number . On D-44 reticle it would be 2-2.5 mils in vertical (between arrowhead and the center) and 1 mil to left, right and down - the central arrow is clearly depressed 1mil below the center !!

Either there is a LOT of innaccuracies in all the drawings (and one real reticle, all 3 photos so far looks the same), or there were indeed multiple variations of PG reticles with different designs of the central part. My manual of D-1 howitzer says PG-1 but it's a post-war (as the howitzer is post war design). Also the border and description of the drawing look not like part of original manual but like it was added in modern reprint. So for texture I would use either your D-44 reticle (from drawing) or better the one from the photo (but are we sure the first two photos are PG-1 ? they are only described as Su-76 sight ?). Anyway most of people reading it are probably regarding this as splitting a hairs

P.S. The thread becomes wider and wider ;P

P.S.2 Could you please check in your D-44 manual, if it's written the same as in mine in reticle description - that vertical marks are made for each 5 mils (it's written as "0-05") ?

 

[mlespaul]

Nahhh, it's a GREAT thread!

It's hard to tell. The manuals' diagrams are basically AFAIK, designed to give the reader a general idea of what they are looking at and what the reticles will look (or SHOULD look) like when they put their eye up to it. I'm sure they weren't drawn architecturally or meant as a template upon which to cut future reticle lenses, but unfortunately, it's all we get sometimes from history. As for the big photo of the PG, I'm not certain about the dimensions of the picture taken, just that I like how you get the optical 'glow' from the real pictures, you know?

As for the types of reticles in the PG series. The PG is the one with the crosshairs, arrow, and grid only.The PG-1 is the one with the added azimuth alphabet line running underneath.

The azimuth line was added (like it was for the RblF 36) as an additional aid to keep the coordinate and azimuth settings ordered by the battery commander. Just like Basil says, the gunner crew would turn the top rotatable lens head in any necessary 360 degree direction(hence, why it was called panoramic, not because it gave a panoramic view of the battlefield, like "cinemascope" or something , it's a 4 X 10) to point it towards the lens of the collimator parked somewhere to the right, left, or behind the battery's (or SP gun's) so that the letters on the PG-1s scale lined up (and stayed lined up after each firing of the gun) on the pre-matched alphabet of the collimator's lens that was being "beamed out". This way they could visually tell just by making sure the letters all matched up that the gun was still aimed in correctly to the strike zone as it was not visible to the gun battery. The picture I posted shows the view of the PG-1 if you were to turn the head in the direct "glare" of the projection of the grid scale provided by the collimator. The collimator is that funny looking thing on the tripod in the lower right quadrant of the FOV:

Here's the collimator:

Here is the reticle of the collimator with it's mad matrix of alphanumeric letters (also from the manual):

Aaaack!!! Wow, what a mess,right? Well it looks like a mess until you look way up close....here's a detail:

And then the matching up of the numbers and letters aiming the PG-1 directly against the oncoming projected/emitted beam of the collimator:

Now the German RblF 36 is basically the same thing with letters and numbers at right angles to each other, with letters going, E, Z, D F, F S,S, N, and the numbers indicating the zone. The letters corresponded to "Eins, Zwie, Drie, Fier, Funf, etc." and so on, so I'm guessing that this is the same concept in Cyrillic.

Amizaur: Bad english translation of text: "The centrally squared grid has a scale of four division on both sides of the central line. The value of each division on the scale is 0-05."

 

[Basil]

This is what was taught to us about the placement of the collimator. The basic direction the barrels are pointing is 30-00 in mils (not 00-00 as one might think) and this scale increases counter clockwise. The collimator is placed approximately into direction 50-00 i.e. 8 o'clock position, and 8-10 meters away. I my memory serves me correct the exact position where it should be is measured with a separate device when the gun is towed into position, but this is another story.

There is also a way to direct the gun without a collimator, and which is much simpler. This consist of a stick and a plate with five balls painted on it. The stick is placed 30 meters away and the plate 60 meters away. They are calibrated so that when looking trough the panoramic telescope the stick must be in the same place as the middle vertical line in the reticule, and they must split half the middle ball painted on the plate. After this it is used so that when a new direction is set and you see e.g. that the stick is on the second ball on the right, you must traverse the gun until the vertical line on the reticule is on the second ball on the left. So basically the line on the reticule and the stick are mirrored in respect of the center of the plate.

It's clearly not as accurate as collimator and is difficult to use if it's dark (someone has to illuminate them with a flashlight), but it's a good backup if something happens to the collimator (e.g. blast wave could top it over etc.) and AFAIK mortar guys use this method exclusively since they don't require such a high level of accuracy. Another way to use it is to place it into direction 20-00 i.e. 2 o'clock position. Then if there's a sudden need to start firing into the other direction (enemy airborne troops make a landing, or there's a breaktrough or whatever) you can just turn the gun 180 degrees and start firing immediately without any additional delays by using this stick and plate.

 

[mlespaul]

Basil -
Awesome. I have been wondering and wondering just how the heck this was all carried out. This answers a lot and I'm saving your notes for future reference .

The circles make sense now as the RBlF 36 had a set of four circles, 2 each on each side of the main upside down V, each one at a right angle to the other and already split in half (like a dark and light side of the moon to show the angle), then the alpha numeric line follows in the horizontal way above. These black and clear circle icons must be what had to be lined up against the sticks guidepoints. (The vertical line on the reticle doesn't go the whole way up and down). I love this stuff.

 

[Basil]

Here's a couple of pics for concretization, the first one taken by a guy serving with me and showing a 152mm howitzer and a collimator (protected by three stick so that people won't accidentaly kick it so easily), and the other one is some official FDF pic showing that plate.

 

[Amizaur]

Great descriptions, thanks !! I knew the collimator was separate device, that it was used during indirect firing and that is was some sort of battery powered device and the light somehow has to got onto the PG, this was all I understood from Russian text (and didn't try too hard as I'm not concerned about indirect firing right now) . In my 152mm D-1 manual there are almost same illustrationsn of PG-1 and collimator, only there is no collimator matrix showed at all.

One question - what is the difference between Rblf36 and SlZF1 ???? I thought the difference was the same as between M-30C sight and PG-1 panoramic periscope (yeah panoramic because of rotational top head - question: was the SlZf1 panoramic too ?).

M-30C was (in my understanding) the mechanical part of the gun D-1 152mm howitzer, with the elevation controls and scales. Picture:

http://img227.imageshack.us/img227/5919/m30csightofd1152mmgunsc6.jpg

It was specific for a gun and a part of a gun. For example ML-20S gun in ISU-152 is said sometimes to have ML-20 sight - but in my understanding this is the mechanical part (like the one on picture) and still a standard artillery panorama goes into it. (not mentoning about secondary direct-fire telscopic sight, that some guns/spg had, as this is not we are talking about here).

The PG was the "optical part" and was inserted in the gun prior to firing, was not neccesarily gun-specific but a standard optical device (artillery panoramic sight) and other could be used, I found info that Russians used German artillery optics sometimes and Germans used Russian PG periscopes in their guns as well if they got one. Not sure if one was better than another, I guess it was just "cool" to use the enemy equipment instead of standard one, or as a backup .

Now I suspected (although I was not sure at all) that Rblf36 was the name of the mechanical part (the one with elevation controls and range scales) mounted on the gun, and into it a SlZf1 was placed as the optical device. I'm talking about self-propelled artillery like Stug now. But you are talking about some optical features of RblF36 now and I'm confused totally...

I guessed also that maybe there were two "optical heads" that could be put into Stug (or another gun) mounting and one was used for direct fire (Slzf1) and the other in indirect fire missions (Rblf36) ? And the "mechanical part" of the sight (which had elevation/range scales on it and is a part of the gun in fact) was called differently ? So now, from what you wrote about RblF36 optics, the second "theory" seems to be true ?

Thanks for clearing up the PG vs PG-1 issue. So PG-1 would be used in towed guns and self-propelled guns (maybe Su-76), and PG would be more likely found in direct-fire devices like assault guns (SU/ISU-122/152) ich do not (or only occasionaly) do indirect fire missions ?

 

[Basil]

I found this kind of forum conversation: http://forum.axishistory.com/viewtopic.php?t=69949

According to that Rblf36 is short from "Rudblinkfernrohr" and SflZF1 is "*something* Zielfernrohr 1". Sfl could stand for "Selbstfahrlafette" (self-propelled) but that's just a guess. With my German skills it's difficult to translate them, but I have a feeling that they are two different optical sights; Rblf for indirect fire (possibly a panoramic telescope) and SlZf1 for direct fire (probably just a tubular scope). Technically the gun could have a separate mount for both types, such things exists, but it's difficult to say for sure. But "fernrohr" stands for scope or similar, so it's certain that they both are optical sights.

 

[Amizaur]

In this case, both were periscopes

http://www.buzznet.com/tags/sflzf/

and this picture is from Swiss Hetzer saved in excellent condition, with complete interior, good page in case of modeling Hetzer internals

note the additional (spare? different?) optical heads.

After all it couldn't be telescope as German Stugs or Jagdpanthers simply didn't have a direct vision slot in front plate... but maybe Slfzf1 was "more simple" model of artillery periscope intended for direct fire only... Not sure if it was panoramic (i.e. the upper part could rotate 360deg) or not.

Have little trouble finding any definite Rblf36 pictures... (usually a picture is signed "SflZFla.Rblf36" or something like that...)

An example of vehicle that have both telescope and artillery periscope would be SU-152 - had a telescope (like in tank, looking trough a hole in the mantlet) for direct fire, scaled only up to 700 or 900m, and also mounting for an artillery periscope for indirect fire and long range direct fire. The periscope was extending outside trouh the roof by the open gunner's hatch (didn't see such photo but it's the only possibility, no other openings) so with closed hatches only the telescopic sight could be used.

 

[mlespaul]

Ami -

Don't get TOO confused. B is right in that the SflZF types were for direct fire and the Rundblickfernrohr "Round-view telescope"
(Rbl.F)-types were for indirect fire. It was basically the duplicate of the PG (although I know the German designed ones were the first ones to come out - the Russians kept close tabs on German technology).

The RblF and SflZF are both periscopic in nature, but serve two different purposes.

The SflZF was designed to overcome the physical design limitations inherent in the armour and slope/physical profile of the Stug armoured vehicles. Limited space meant no room for a long, telescopic gunsight as used in more standard turreted tanks, so the SflZF was born to give a gunsight FOV for the gunner without having to redesign or compromise the thickness of the armour to accomodate a traditional (horizontal) telescope.

Also the SflZF in and of itself has no range scale in it's reticle By design, it is attached to a physical range drum inside the fighting compartment of the AFV.
The Rbl.F, also has no range scale in it's reticle (I don't mean the azimuth alphanumeric markings), and it too, is placed in a holder next to a range drum that controls range and elevation just like regular artillery.. RblFs were part of mobile artillery AFVs like the Marder, Hummel, etc. --they were basically just artillery pieces on tracks..I have TONS of pictures of RBlFs...trust me

For the Hetzer, the secondary scope heads for those SfLZFs you have in the picture are only replacement. There is no reticle in them, they are just the mirrored glass that reflects the light from outside then down into the reticle which is inside the lower part of the optic. When damage occurs (stray bullet or shrapnel hits the exposed top of the SF, it can be easily switched...because it was exposed to the outside, it needed replacement tops.)

The vision in the Jagdp and Hetzer for gunners was limited. The driver had a small vision port, but nothing for the gunner other than the SFlZF. It was a bad design for overall visibility for crewmembers.

Amizaur - please write or pm me on this...I have a whole complete library of images and documentation on RblFs and SflZfs...I can give you anything you need....I've been around the whole block on this one already

.....The issue here is whether RO really gains any additional playability through the use of indirect fire sights.....other than authenticity....

...unless when the call goes out to request artillery fire...then its up to a player to run back and man an artillery piece and start shooting a pre-staged piece against the coordinates that are given...even if the player can't see what he's firing at....now THERE's an idea...

 

[[TW]Wilsonam]

I found this kind of forum conversation: http://forum.axishistory.com/viewtopic.php?t=69949

According to that Rblf36 is short from "Rudblinkfernrohr" and SflZF1 is "*something* Zielfernrohr 1". Sfl could stand for "Selbstfahrlafette" (self-propelled) but that's just a guess.

1. RuNdblikfernrohr and yes, self-propelled. I've even had the chance to play with one

2. Ok, who is going to write the book on this lot (Mlespaul?? - or do we just head for your website ?).

3. I doubt RO gains anything from the use of indirect fire sights - but I could see it all being used for a heavy-duty sim game. The "correct" direct-fire sights are of interest to us, of course!

 

[mlespaul]

1. RuNdblikfernrohr and yes, self-propelled. I've even had the chance to play with one

2. Ok, who is going to write the book on this lot (Mlespaul?? - or do we just head for your website ?).

LOL..yeah...I'll really have to update that circus with the RbLF . I seem to have gotten hung up after my front page got all hosed up by putting in the chapter on the DF 10 x 80 Flakglas. Still wrestling with all the Flak observation optics.... I'll finish that and start on the RblFs, next I suppose....then it's the TZFs...I promise I'll get to it....soon...I swear....

You are supposed to read it from top to bottom, like a book..chapters on right hand side...."Foolhardy undertaking" (and it really is) is supposed to show up first, but again, I buggered something while trying to add a chapter...I make mistakes, too....

germanmilitaryoptics.wordpress.com

3. I doubt RO gains anything from the use of indirect fire sights - but I could see it all being used for a heavy-duty sim game. The "correct" direct-fire sights are of interest to us, of course!

Yup, ONLY if someone REALLY wanted to run himself "red" all the way back to spawn zone where the Feld haubitzes are and get behind one and 'throw some', but it's missing the instant gratification element...., but yeah if people were really into the team concept...someone might be willing to stay behind and fire at coordinates...but I doubt it.


For Amizaur

1) RBl.Fs (and Russian PGs) are periscopic AND Panoramic (the head turns 360 on an axis and has azimuth settings around their 'necks') and are really meant to be aimed at a scale set up in the field to help maintain correct "laying" of the guns between shots fired.....but.... it COULD be used for direct fire.....if it HAD to...but..mostly for indirect fire....like setting up a bunch of SU-76s and throwing shots at The Ruins!!!

2) SFl.ZFs are periscopes but do not turn their heads.....used for engaging targets for direct fire...they have the Big and small triangles in the reticle....they are 'fixed' and 'forward' directional only. When mounted on the JagdP and Hetzer carriages they are afforded SOME lateral movement, but it is strictly limited to the lateral movement of the gun within the AFV fighting compartment and follows the size and shape of the slot built into the hatch on the roof of the compartment. Those extra heads only contain prisms and mirror and glass for quick replacement upon shattering.....like vacuum cleaner attachments.......and they just twist and lock, no rotation of any sort.

3) The Hetzers and JagdPs had some visual periscopes of the square block variety that could indeed turn by hand at some limited angles, (or were they 360, too?), like you see on all tanks, but that was about it, and they weren't designed for any long range magnification, per se.

4) There IS one exception...The MG 34 ZF that was on the hetzer that was controlled by a periscopic attachment that the commander could operate from below and rotate the upper deck MG. It was an unGodly contraption that was sort of a Frankenstein-built piece of pipes, handles and periscope that fit directly below the MG. The reticle was a simple ZF 3 x 8 (exactly the ones as used on the PaK guns) that was inserted into the assembly, snapped together and poof....instant periscope gunsight.... That thing will be going into the website too....

Ok, I need to stop........are we done yet, AW?

 

[Basil]

1. RuNdblikfernrohr and yes, self-propelled. I've even had the chance to play with one

Ok, that finally makes sence. I was wondering that wtf does "rud" mean since anything even remotely similar that I found from my German-Finnish dictionaries had something to do with rowing which hardly is the case here.

 

[Amizaur]

Thanks ! So RBlf is just a German version (original) of the artillery periscopic sights. OK, I've seen pictures of those only didn't know it is called RBlf now I have name linked with the pictures I've seen )

Guys, I never intended to put indirect sights (or more precisely, indirect sighting ability) to RO as we all know it's almost useless (edit: it would be completly useless in fact, for typical ranges on RO maps, even tank maps, only mortars are used to bring indirect fire, or SOMETIMES a very low velocity infantry guns... beside this, to lay indirect fire the sight is not enough, you also need a real, precise and functional map and few tools

I've said few times that I was not concerned too much about understanding how the "indirect" part of targeting and sight functionality works, as I don't need it for RO, so no worry My only interest in indirect sights is because some vehicles/guns have only such sights (like Su-76, ISU-152 for long ranges) and they just have to use it for direct dire as they have nothing else. I'd like to understand what is what and how it works (at least regarding to direct fire, and beside this I'm a curious person) but it doesn't mean at all I'd like to code full indirect sighting capability into RO

 

[mlespaul]

I've said few times that I was not concerned too much about understanding how the "indirect" part of targeting and sight functionality works, as I don't need it for RO, so no worry My only interest in indirect sights is because some vehicles/guns have only such sights (like Su-76, ISU-152 for long ranges) and they just have to use it for direct dire as they have nothing else. I'd like to understand what is what and how it works (at least regarding to direct fire, and beside this I'm a curious person) but it doesn't mean at all I'd like to code full indirect sighting capability into RO

No problem, I share your interest and enthusiasm, as do a few others here...it makes the research experience that much richer!

Can indirect sights be used for direct fire? Absolutely. Are they as accurate? Depends on how the gun or SP is seated on the terrain, if the barrel is zeroed 1:1 with the top point of the upside down V, or the intersection of the crosshair....all things that the crew had to work hard to do if they were taking an SP equipped only with an indirect sight into direct combat....so I mean to say, just because it only has an indirect sight, don't let that keep it from being in the game, IMHO.
...but as you can see by my pictures at the very top of the string, the SU-76 crew didn't seem to have a hard time using the PG!