Some Giro thoughts

[KV7]

'On the other hand most of them had optical rangefinders which the soviets lacked until early T-64s and T-72s'

My understanding is stadiometric optical rangefinders till 74, then laser after that. T-55A gets 'Newa' TKI laser rangefinder in 74.

[Marcello]

My understanding is stadiometric optical rangefinders till 74, then laser after that. T-55A gets 'Newa' TKI laser rangefinder in 74.

Naturally stadia lines were used for ranging with the sights, but this is not comparable to a full blown coincidence/stereoscopic rangefinder as employed on the early
T-64/T-72 and 60's western MBTs.
With stadia lines you are essentially guessing range on the basis of the apparent size of the target: if it looks big it means it is close, if small it's far. One problem is, the stadia marks used for measuring have to be calculated and drawn for a predetermined target; if the target differs from that, because of profile, actual size etc. accuracy is off. This is not an issue with the latter types.
Now, how much this is an issue in real life battles I don't know, but adding a relatively maintenance intensive piece of kit must have been felt to be an advantage, at least for the type engagements planned (same applies to stabilizers on russian
T-XX).
It has been reported that there was an istance of iraqi T-55s engaging USMC AMTRACs and missing with all shots falling short. Supposedly because they were bigger than the standard size target, so they appeared closer than actually were and therefore insufficient superelevation was applied. But such stories have to be taken with pinch of salt.

[KV7]

Marcello, yes of course stadiometric range-finding is pretty inferior to coincidence, the method is really a multiple round one, the first shot determines the error which is then corrected, hence the almost universal use of use of AP-T rounds on the D-10T, the tracer allowing easier spotting of range error. A skilled gunner could of course estimate the ratio of the size of the target against the target the Stadia was designed for, and make some first round correction.

When did Russian tanks get coincidence rangefinders, and on what models ? My understanding was there was a transition straight from stadiametric sights to the TK-1 system.

For example, the T-62 has stadiometric rangefinding with TSh-2B-41 gunner day sight (3.5/7x)and TPN1–41–11 night sight from 1960 till 75, where it then gets the TK-1 or TK-3 laser system.

Was there a coincidence system installed between 1960 and 75 ? I cannot see any mention of it ?

[Mobhack]

No USSR units that I know of used optical rangefinders - they went straight from stadia to LRF in the 70s on later model T-72 and 64 etc.


Andy

[KV7]

Thanks Andy that was my understanding.

I have one more question, how long did it take to range and aim with the Volna FCS, what was automatically entered and what was manual ?

My understanding is turret traverse speed is entered automatically from sensor in the turret ring, but round type, temperature, and range manually entered, with range determined from TK-1 laser rangefinder.

Once the solution was found, did the chevron (dot) on the scope automatically move, or was there simply some increments (for lead and super-elevation) that had to be matched manually to the solution produced by the computer ?

[Marcello]

Originally Posted by Mobhack

No USSR units that I know of used optical rangefinders - they went straight from stadia to LRF in the 70s on later model T-72 and 64 etc.
Andy

I have to disagree. Early T-72s were fitted with the TPD-2-49 coincidence rangefinder.




Notice the rangefinder ports on the turret roof near the sides. Early T-64s had a similar arrangement.
Naturally T-55/62 went straight to lase but as I said early production T-72/64 relied on optical units.

[KV7]

Marcello is of course correct, optical rangefinders were installed in the first T-64 A modernization in 69/1970, apparently lasers were not fitted till 81.

[Mobhack]

Hmm - you do learn something new, from time to time!

(And it looks as though these are already factored in the OOBs from a look at the R/F values)

Andy

[KV7]

I would pity the poor crews trying to shoot in the dark with nothing but stadia in the night sight on a late 70's battlefield though !

Marcello, TPD-2-49 is listed as a day sight, so is the rangefinder and sight the same unit, or is it two pieces of equipment, with the operator ranging with the rangefinder, then(manually) matching the range to a superelevation mark on the gunsight, as in a non automated laser system ?

[Marcello]

Originally Posted by KV7

Marcello, TPD-2-49 is listed as a day sight, so is the rangefinder and sight the same unit, or is it two pieces of equipment, with the operator ranging with the rangefinder, then(manually) matching the range to a superelevation mark on the gunsight, as in a non automated laser system ?

It is an integrated unit. You range and aim looking in the same sight. There is a video of the operation available at this page
http://www.t-72.de/html/tpd-2-49.html

Originally Posted by KV7

I would pity the poor crews trying to shoot in the dark with nothing but stadia in the night sight on a late 70's battlefield though !

Max vision range on the most common export (something better was available but not widely used outside USSR) T-72 night sight supposedly was 600-800 meters, with one km achievable only under optimal conditions. At those ranges you could fire APFSDS without worrying too much about ranging and superelevation.