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Author Topic: Tu-2 variants  (Read 8103 times)
KL
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« Reply #15 on: August 28, 2013, 11:20:02 PM »

I still feel that the terminology is a translation difficulty, and do not accept that using "series" rather than "block" or "batch" is necessarily any improvement, but let's move on to the aircraft side.

I am not insisting on anything - if "block" is more appropriate for Russian "seriya" (note that it is singular), we should start using "block" for LaGG-3, Pe-2 or SB Series too.

At first sight the size of each Series appears low, considering that over 3000 examples were built discounting the later Irkutsk builds.  By this listing, no more than 780 had been built by June 1945.  Gunston (Tupolev aircraft) states that the main production was on two lines, GAZ 166 and 156 (starting slightly later).

My mistake - Zavod No 23 must have increased Series size from 20 to 50 in late 1944 or early 1945.  Gunston was also wrong, there was no parallel production in two factories during the war.  Main wartime production was in Moscow Factory 23.  Production from 1942 to 1945 was as follows:

Zavod 166 Omsk
1942 - 79 planes
1943 - 1 plane

Zavod 23 Moscow
1943 - 16 planes
1944 - 378 planes
1945 - 742 planes

After the war in 1946 - 1949, production was reinstated in Omsk with about 200 planes produced.  For Omsk, those postwar Tu-2s were series 8 to Series 18...

Zavod 39 in Irkutsk made further 200 or so planes between 1947 and 1950.  Balance to 2500 was made in postwar years by Zavod 23 in Moscow.  

 
« Last Edit: August 28, 2013, 11:28:07 PM by KL » Logged
Graham Boak
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« Reply #16 on: August 29, 2013, 11:58:16 AM »

With these figures I think you were right at first, but it may depend upon where "postwar" is set to start.  If Zavod 23 Series 35 appeared in June 1945, this is consistent with 20 aircraft per series up until then. This assumes no major change in production rate in 1945.

I now have a clearer picture of most of the features affecting the external appearance, but am still uncertain about the wartime (or not) existence of the triple windows for the ventral gunner.  This would affect judgement on the colour scheme appropriate to these aircraft, I suspect.

Or indeed whether my ICM kit is correct in having a slightly bulged starboard side window on the late canopy, or whether this is a moulding flaw - it does seem to fit the window size rather too well to be mould damage.
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KL
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« Reply #17 on: August 29, 2013, 09:50:00 PM »

I've just browsed through Kotelnikov & Saukke's Tu-2 Aviakollektsiya issue (probably the best published reference) and it looks that triple windows for the ventral gunner are OK for wartime planes.  Profiles representing Omsk Series 1 and Series 3 have one small window, Omsk Series 6 has triple windows.  Triple windows remained standard at least till 1946.  One larger side window for the ventral gunner was among improvements proposed at the end of 1945.  Some of these improvements were included in 44th Series produced in early 1946 (according to the profile one large window was included in 44th Series).  Other improvements like bulged rear part of the cockpit canopy were introduced in early 1947 with Series 50.

Quote
The 4-bladed props are linked to block 59, together with larger fins and rudders (sensible enough to an ex-aerodynamicist)...

Larger fins and rudders were introduced with the beginning of production in Moscow (i.e. with the beginning of production of the Tu-2S), nothing to do with 4-bladed props...  Tu-2s made in Omsk (a.k.a. Tu-2VS) had smaller fins and rudders.

4-bladed props were introduced from the 21st plane of the 59th series in Moscow and from the 17th plane of the 5th postwar Series in Omsk, probably in late 1947.

Hope this helps,
KL 
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Graham Boak
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« Reply #18 on: August 29, 2013, 10:42:37 PM »

Yes, indeed, thank you.  I had wondered whether the reference to the triple windows appearing in Series 44 should really have been the reverse.

I'm a little surprised to see changes such as the 4-bladed propellers) being introduced in the middle of a Series.  I'd assumed that all the aircraft in a series would be to the same build standard.  This suggests that the Series number may not have been as useful for supply purposes as I'd assumed.

The reference (Gunston) to a change in tail size was to the 59th Series and apart from any change early in the aircraft's life.  The 4-bladed propellers would have been slightly destabilising so a larger fin would not be surprising here.  I've seen no photos showing any such change, but later examples seem to be less well recorded, and any small difference may not be obvious.  The Tu-10 does look to have had a slightly larger fin (and is so described), but this could have been predicted for the longer (inline) engines.  For the Tu-2S directional stability is said to have been comparatively poor (Gordon), so change in this area would be expected.  Is it possible that the increase in tail area followed the initial trials rather than always having been part of the revised design?

It therefore seems that the Hobby Boss kit, though somewhat basic, only needs a different camouflage scheme; whereas the superior ICM kit requires a change to the ventral gunner's windows.
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KL
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« Reply #19 on: August 29, 2013, 11:47:34 PM »

Quote
I'm a little surprised to see changes such as the 4-bladed propellers) being introduced in the middle of a Series.  I'd assumed that all the aircraft in a series would be to the same build standard.  This suggests that the Series number may not have been as useful for supply purposes as I'd assumed.

In theory that should not have happened. In reality, it happened quite often, especially with various equipment modifications.

Quote
For the Tu-2S directional stability is said to have been comparatively poor (Gordon), so change in this area would be expected.  Is it possible that the increase in tail area followed the initial trials rather than always having been part of the revised design?

According to 1943 NII VVS tests directional stability of Tu-2 was worse than directional stability of A-20 or Yer-2, but better than Pe-2.  In February 1944 one Omsk Tu-2 (No 100716, i.e. 16th machine otf the 7th Series) was modified with enlarged fins and rudders, it was tested in March and modification was recommended for the series.
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KL
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« Reply #20 on: August 30, 2013, 01:15:58 AM »

...  This suggests that the Series number may not have been as useful for supply purposes as I'd assumed.

Series as batches of identical planes were introduced to deal with delays in production caused by the modifications.  Series were never seen as designations for new modifications; they were never seen as useful for supply purposes.  VVS never referred to modifications by Series.  On the other hand, Series were used in manuals to designate modifications (manuals were usually made by design bureaus attached to the main production facility) and that is why modern historians and modellers use Series to describe modifications.

HTH,
KL

 
« Last Edit: August 30, 2013, 09:09:06 AM by KL » Logged
Graham Boak
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« Reply #21 on: August 30, 2013, 12:43:39 PM »

It is therefore a logical implication that early Series from Zavod 23 in Moscow will have had the lower, rounder, top to the fin.  This presents another option for modelling: it will be interesting to look at photos to try to identify these aircraft.  It would be interesting to know the series in which they were introduced, clearly long before the 59th.  Differences in the rudders does not appear obvious - at least I can't see them.  It is possible that earlier aircraft were upgraded.

For supply purposes, it is necessary to know which parts are required by which aircraft.  If this is how the manuals handle the matter, I'd have expected the supply system to do the same.  To make a crude simplification, if the Southern front has no aircraft before Series 20, there would be no point in local stocks of parts superseded by Series 15.
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KL
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« Reply #22 on: August 30, 2013, 08:36:36 PM »

It is therefore a logical implication that early Series from Zavod 23 in Moscow will have had the lower, rounder, top to the fin.  This presents another option for modelling: it will be interesting to look at photos to try to identify these aircraft.  It would be interesting to know the series in which they were introduced, clearly long before the 59th.  Differences in the rudders does not appear obvious - at least I can't see them.  It is possible that earlier aircraft were upgraded.

Correct, early Tu-2S made by Factory No23 had smaller tail fins.  It is not clear when larger fins were exactly introduced.  Tu-2S (16th plane of 7th Series, made in june 1944) tested by NII VSS in Oct 1944 had larger fins installed.
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