Various Aircraft Specifications for a Video Game Mod

[Denniss]

the range discrepancy might be combat vs ferry range

 

[Wurger]

Though I guess there's nothing really contradictory about both Tu-2 and Tu-2S not having air brakes. It just seemed a bit odd to list the removal as a change on the Tu-2S if the brakes were already removed on the Tu-2

The order you quoted above about the removing of the air brakers beginning the 6th plane doesn't reffer to the Tu-2S but the to the Tu-2 ( plane 103V ) assembled by the factory no.166. As you may noticed in the pics posted above the factory attached them to the initial series of the bomber. So again a matter of translation I would say.

Do you know if the DB-3T and/or IL-4T carried extra fuel compared to their standard bomber counterparts? Soviet Combat Aircraft of the Second World War lists the range of the DB-3T as 1800km while I've found a figure of 3800km for the Il-4T online. The first figure is much lower then the range figures listed for standard DB-3s and makes me wonder if someone made an error while typing, while the later figure is actually a little higher then the range usually listed for a standard Il-4.

The difference in the range you found , is because the range depended on the bombload. Many authors just simplified their statements for the range without saying what was the bombload or if it was the maximal range. The TBiU no.223 booklet for the DB-3/Il-4 says that the range for DB-3 was 2000km while the DB-3A 1600km , DB-3B and DB-3M had 1500km. DB-3F and Il-4 1800km. But it is the range with the maximal bombload. The maximal range for DB-3/DB-3A was 4000km while the DB-3B 3800km, DB-3M 3500km, DB-3F 3300km and 4200km for Il-4. The maximal range is for the standard bombload for all of them that was 1000kg. The maximal bombload was about 2500kg. So with the maximal bombload of the 2500kg the range was about half the size . Also it appears that the range depended on the year and the factory the tested plane was made by and modifications introduced.
According to a note in the mentioned booklet the DB-3T and Il-4T didn't vary too much in the data from their bombing version these based on.
Regarding the extra fuel for DB-3T/IL-4T... the info can be found in the booklet as well. It states that DB-3/Il-4 could carry additional external fuel tanks on the external racks. So the torpedo variants could do that as well. But not sure if these were attached when the torpedo was racked though. I haven't seen any image of the T version with the additionall external fuel tanks. A shot of the bomber yes I have ... see below.

A very different question: was it common for Soviet fighters to use bombs and rockets to support ground troops, or was that mission left to the bombers and shturmoviks?

I wouldn't say it was common. Let's say, for the reason there was designed so many variants of a plane. Just if a such assault plane was needed at the frontline, a plane with the kind of armament was introduced. It can't be said that there were the soviet universal planes at the beginning of the war. However, at the end it can be noticed that the soviet aircraft became more multi-purpose planes.

 

[Darthtabby]

The order you quoted above about the removing of the air brakers beginning the 6th plane doesn't reffer to the Tu-2S but the to the Tu-2 ( plane 103V ) assembled by the factory no.166. As you may noticed in the pics posted above the factory attached them to the initial series of the bomber. So again a matter of translation I would say.



The difference in the range you found , is because the range depended on the bombload. Many authors just simplified their statements for the range without saying what was the bombload or if it was the maximal range. The TBiU no.223 booklet for the DB-3/Il-4 says that the range for DB-3 was 2000km while the DB-3A 1600km , DB-3B and DB-3M had 1500km. DB-3F and Il-4 1800km. But it is the range with the maximal bombload. The maximal range for DB-3/DB-3A was 4000km while the DB-3B 3800km, DB-3M 3500km, DB-3F 3300km and 4200km for Il-4. The maximal range is for the standard bombload for all of them that was 1000kg. The maximal bombload was about 2500kg. So with the maximal bombload of the 2500kg the range was about half the size . Also it appears that the range depended on the year and the factory the tested plane was made by and modifications introduced.
According to a note in the mentioned booklet the DB-3T and Il-4T didn't vary too much in the data from their bombing version these based on.
Regarding the extra fuel for DB-3T/IL-4T... the info can be found in the booklet as well. It states that DB-3/Il-4 could carry additional external fuel tanks on the external racks. So the torpedo variants could do that as well. But not sure if these were attached when the torpedo was racked though. I haven't seen any image of the T version with the additionall external fuel tanks. A shot of the bomber yes I have ... see below.

View attachment 630425



I wouldn't say it was common. Let's say, for the reason there was designed so many variants of a plane. Just if a such assault plane was needed at the frontline, a plane with the kind of armament was introduced. It can't be said that there were the soviet universal planes at the beginning of the war. However, at the end it can be noticed that the soviet aircraft became more multi-purpose planes.

I think there's some confusion with the Tu-2 question because I linked to a page on the early Tu-2 and a page on No.716 (the main development aircraft for the Tu-2S), but I only quoted the first page on the early Tu-2. The page on No.716 says this:

The standard Tu-2 was characterized by the following changes:
They were removed from the aircraft, but can be delivered by special order:
a) brake grids with a control system and grid communication with a dive machine,
b) AK-1 heading machine,
c) gas tanks No. 8, 9 and 10 (the decrease in the amount of fuel is compensated by the increase in the volume of tanks No. 1, 6 and 7),
d) ShKAS front machine guns.
The hydraulic system, made according to a simplified scheme, is characterized by:
a) transition to one high pressure system,
b) combining the control of the front, side and oil flaps for one control with a mechanical connection between the side and oil flaps,
c) removing the automatic thermostats,
d) transferring the main lines to the area of the front spar, where they are protected by armor, gas tanks and structure,
e) removing the automatic control of the stabilizer, which is fixed motionlessly,
f) replacing the hydraulic control of switching the speeds of the motor superchargers to a mechanical one,
g) transferring the hydraulic reservoir and manual pump into the forward cockpit, behind the navigator's upper armored shield.

It seemed odd to say that dive brakes were removed on the Tu-2S if they were removed on the early Tu-2 before. But I guess on Tu-2S the dive brakes could be installed as "special order" equipment. Do you know if any Tu-2S used this "special order" equipment?

Basically I wanted to see if Tu-2 and Tu-2S should be seen as dive bombers or if they should be seen strictly as level bombers. So far most evidence suggests they should be seen as level bombers. Sorry for the confusion.

Soviet Combat Aircraft of the Second World War doesn't list the A, B, and M designations for the DB-3, just DB-3, DB-3F, and IL-4 (plus DB-3T and DB-3TP for the torpedo bomber and float plane variants). It does have data for a variety of engine fits though including the M-85, M-87A, M-87B, M-88, and M-88B. I am pretty sure the ranges it gives for the conventional bomber are with a standard 1000kg bomb load. (Edit: Actually the text says the 4000km for the early DB-3 was with a 500kg load, though it uses 1000kg for the 3585km of the IL-4.) I'm not sure about the torpedo bomber variants though. I know the torpedo would add drag due to external carriage, but it weighs about the same as a standard bomb load so it shouldn't reduce the range by half. I did read that IL-4Ts were occasionally flown with two torpedoes so if its not an error maybe the 1800km for the DB-3T is for when its carrying two torpedoes?

The game mod I am gathering information for has both fighters that can only do air to air and fighter bombers that can do air to ground and air to air. The mod team decided that just being able to carry bombs is not enough to make a fighter a fighter bomber. They decided that it needed to be used for ground attack often. So a Spitfire would not be considered a fighter bomber even though some could carry bombs, but a Typhoon would be considered a fighter bomber because it frequently carried bombs or rockets. That is why I wanted to know how often Soviet fighters were used to do ground attack -I wanted to tell if the game should see them as fighters or fighter bombers.

 

[Wurger]

I haven't heard about any special equipment for the Tu-2S. Just the very early Tu-2 assembled by the factory no.166 had them only. Then they stopped mounting of them. Long time ago I read that Tupolev and his OKB found them unnecessary because it was possible to dive with the speed up to 900km/h and then got the flight at a level without any trouble.. Therefore the OKB and the main designator decided to remove the air brakers. It allowed them to save some of the weight and made the servicing much easier as well.
Regading the link and the text you quoted .. the idea of a Tu-2 that would be an universal plane appeared not to be correct fully. It was found that assembling of a such kind of a plane was quite complex and its maintenance was hard. As a result they decided to simplify the construction and make something that could be a base for other but more special purpose planes , for instance a diving bomber or a scaut plane. Therefore the air brakers were predicted as the option just in case if the VVS would order a diving bomber. But It seems it never happened and the idea was left on the paper only. Most of tasks for diving bombers could be done by the standard level bombers and the Tu-2S just was a such one. So I understand your confusion now.

I agree that the A, B, and M designations for the DB-3 weren't the next variants of the bomber actually. When the DB-3 was tested it appears that there were issues that had to be removed although the plane was very promising. The test pilots opinions were very fine. But the aircraft needed a couple of modifications. For the reason the OKB and the factory introduced the new sub-type names but in fact these were the time slots or better, the periods of time for the planned entire process of modification to get the final product. It just so happened that the sub-types got the name because of the engine variants used for the powering.
Regarding the torpedo varints.. the torpedoes were carried on the external racks. So if the 45-36-AH or AV torpedo weigth was about 1000kg it couldn't be possible to take more theoretically. But if you racked the two torpedoes, the bombload was about the maximal one and no more could be taken. I must admit I also read the there were pilots who took two torpedoes flying the DB-3T but they seemd to be the individual cases. IMHO this is the same like for the Pe-2 or Yer-2 bombers. The larger bombload you carried the less of the fuel you had to take. So the range wasn't too impressive. So again I say that the maximal bombload stated in most sources doesn't mean the bomber could take it fully. The same is with the range. All depened on the bomb configuration and the task to complete.
Here is the data sheet from Vladimir Kotelnikov's book " Il-4 Stalin's air cruiser" . Please note that the range varaied depending on the time , factory etc... also please pay your attention to thase notes below.

the pic source: the Internet.

The game mod I am gathering information for has both fighters that can only do air to air and fighter bombers that can do air to ground and air to air. The mod team decided that just being able to carry bombs is not enough to make a fighter a fighter bomber. They decided that it needed to be used for ground attack often. So a Spitfire would not be considered a fighter bomber even though some could carry bombs, but a Typhoon would be considered a fighter bomber because it frequently carried bombs or rockets. That is why I wanted to know how often Soviet fighters were used to do ground attack -I wanted to tell if the game should see them as fighters or fighter bombers.

And I again answer.. not as often as it would be expected. Fighters were used for dogfights and protection missions for bombers or sturmoviks. However the soviet VVS regiments consitsed of both fighters and their versions for ground attacking. For instance I-16 as a fighter and I-16 with RS-82 missiles as the assault plane. But it doesn't mean the I-16 with the rockets could be the full fighter. Usually a such modification made by the soviet designators was achieved at reducing of number of guns and the suplay of fuel etc... deteriorating the performances often. So a such modified plane couldn't be so effective as the standard fighter machine. However it seems that such modified fighter planes were used more often at the beginning of the Fall Barbarossa than at the mid or the end of the war. The more frequent using at the beginning of the invasion was caused by the quick German's advance and a desperate attempt to stop them at any cost.

 

[Wurger]

Not sure but it may come in handy... https://oat.mai.ru/gal_la_1/la19_34/TXT_05.html#3

And also the data for both the DB-3T and Il-4T for comparing found on via the online sources .. as you may see even Russians are not sure ...

 

[tomo pauk]

FWIW, the table for different Klimov engines, from 'the TsAGI book':

 

[Darthtabby]

Thank you Wurger for the info on the DB-3/IL-4, and thank you Tomo Pauk for the info on the Klimov engines. I should have thanked you earlier.

I have not been around much the last couple of weeks, partly because I've been busy and partly because I managed to finish up the DB-3/IL-4, Yer-2, and Il-2 info documents without having to ask more questions. I am also getting close to completing an info document for the Sukhoi Su-2 and Su-4, but there's a few things I am hoping to clarify.

1) Does anyone have documentation showing the take off power for the the M-87, M-88, M-82 engines? Some of my info is contradictory, and I think one of my sources may have gotten the M-87 and M-88 mixed up.
2) The data table in Soviet Combat Aircraft of the Second World indicates that the Su-4 had 2x12.7mm and 2x7.62mm guns. Assuming this is accurate, which 7.62mm SHKAS did the 12.7mm weapons replace -the four forward firing SHKAS, or the SHKAS in the dorsal and ventral positions?
3) Soviet Combat Aircraft of the Second World War also says that during state trials the "Ivanov" that the BB-1/Su-2 was based on carried a 400kg load in bomber configuration, a 200kg load in attack configuration, and a 1000kg maximum load. It later lists 600kg as standard load for the production BB-1, while the data tables list 400kg for the prototypes and the BB-1/Su-2/Su-4 production aircraft alike. An online aviation museum page I ran through google translate said that 400kg was the standard load and 600kg the maximum. Does anyone have access to sources that might clarify which of the figures are correct?

 

[Wurger]

Ad.2 ... the 2x12.7mm BS guns were mounted in the center wing replacing the 4 or 2 SHKAS MGs installed there for the Su-2. The SHKAS MGs were left for the dorsl turret and the ventral one.

Ad.3 ... Indeed, the SZ-3 powered by the M-62 engine and the "Ivanov" with the M-87A motor had the bombload of the 200kg only. Beginning with the BB-1 powered by the M-88 engine and later Su-2, the standard bombload was of the 400kg but it could be increased to the 600kg maximally that was the overloading actually. The total bombload consisted of the internal load ( 0-400kg ) and the external load ( 0-500kg ). The possible combinations for the internal load were ... 30х8 kg, 30х10 kg, 20х15 kg, 20х20 kg, 12х25 kg, 4х50 kg, 4х100 kg. The external racks could carry 2x250kg bombs maximally or with the cassette KD-1 or KD-2 racks 14 very small ones or 10xRS-82 or 8xRS-132. According to that it was possible to carry maximal 400kg in the bomb bay and 2x100kg externally. Alternately there could be 400kg loaded internally and 8-10xRS externally. So again the maximal bombload depended on the combinations. If you racked the full 400kg internally you could load only 200kg externally and vice versa. So if you racked the 2x250kg externally you could load 100kg only internally. But the configuration diagram shows the 2xFAB250 on the external racks only what is 500kg. So the maximal bombload of 600kg seems to be the correct while the info about the large load (1000kg) I found says that it was 1200kg (12xFAB100) on the KD-2 racks or 840kg (42xAO-20M) with the KD-1 ones. But there is a note saying that the overloaded plane shouldn't carry more than the 400kg as the bombload. So I think, the Su-2 has never carried more than the 600kg.

the source:
Nikolay Gordjukov & Dmitriy Kazanov book - Ближний бомбардировщик Су-2
Dmitriy Kazanov book - Cу-2 принимает бой
бомбардировщик Су-2

Ближний бомбардировщик Су-2 (СССР)

История создания, модификации и боевого применения советского бомбардировщика Су-2.

armedman.ru

 

[MiTasol]

at last I have re-found the Russian Central Air Force Museum restoration site Aviarestorer.ru and bookmarked it again.

 

[Wurger]

Ad.1 ... the Russian online sources say:

the M-88
take off mode:
power - 1100 KM
engine speed - 2300 rpm

nominal mode:
power at the ground level - 840 KM
power at the level 4000/4500m - 1100 KM

the M-87
take off mode:
power - 950KM
engine speed - 2250 rpm

nominal mode:
power at the ground level - 800KM
power at the 4000m - 950KM

the M-82 (ASh-82)
take off mode:
power - 1700 KM
engine speed - 2600 rpm

nominal mode:
engine speed - 2400 rpm
power at the ground level - 1400 KM (1500 KM)
power at the level 2060m - 1540 KM (1550m - 1530 KM)
power at the level 5400m - 1330 KM (4550m - 1330 KM)

 

[Darthtabby]

Thanks for all the info on Soviet aircraft everyone. I will probably be doing more work on them.

I have a question about an American plane for a change. What are the bomb loads of P-40's prior to the P-40N? I am particularly interested in the C model -some sources indicate the C model's centerline station was for fuel tanks only. An interview with a veteran suggested a few 30lb bombs could be carried instead of a tank though. And it seems to me if it could carry a ~360lb tank why not a 250lb bomb? I am also interested in the weight ratings for the underwing pylons on various pre-N series models.

 

[GrauGeist]

If memory serves right, the P-40C (Tomahawk) was fitted for a 52 gallon centerline drop-tank.

It wasn't until the Kittyhawk series that they were equipped for a 75 gallon droptank.

 

[MiTasol]

52 USG of fuel weighs about 320 lbs plus the weight of the tank so to me 360 is not an unreasonable estimate.

So long as the side stays can be adjusted to support it technically there is no reason that a 250lb bomb could not be carried. The release would be the same as dumping a tank so no finesse in aiming but that applies to the later aircraft as well.

Both bombs and tanks use the same shackles.

 

[Darthtabby]

I took another look at the copy of America's Hundred Thousand that I borrowed from the library. While the section on Model Changes and Characteristics for the P-40 only credits the C with a "52 gallon external belly tank fuel installation" (while the D model is listed as having a "fuselage centerline rack for 500 pound bomb") the Armament Provisions section states that "The C model could also carry a 500 pound bomb on the centerline." Though it doesn't mention anything about the release mechanism like it does for the centerline installation on the E model.

Unfortunately America's Hundred Thousand doesn't seem to be anything about the weight rating of the wing racks prior to the N-20 model which was noted as being able to carry three 500 pound bombs (presumably one on the centerline and one under each wing).

 

[MiTasol]

One thing I forgot to mention is that a lot of the D through M model P-40s on could carry a number of light bombs under each wing using internal racks. I do not know if it applied to all or just some. It was on all M model aircraft so I would suspect all D through M.

 

[Darthtabby]

One thing I forgot to mention is that a lot of the D through M model P-40s on could carry a number of light bombs under each wing using internal racks. I do not know if it applied to all or just some. It was on all M model aircraft so I would suspect all D through M.
View attachment 638353
View attachment 638354

That's probably why Dean lists the D model as having "wing racks" and the E model model as having "no wing racks." The E-1 is listed as having "Wings strengthened for bomb racks" which implies heavier ordnance though perhaps not to the extent of some of the N model sub variants.

I found another book that was specifically about the P-40 yesterday. According to that book the bomb rack on the P-40C was specifically for fuel tanks -it could technically be fitted with a bomb, but lacked provision for an arming wire to prevent the fuse from spinning until the bomb was released. This was apparently because the USAAF wasn't keen on having its fighters tapped for close air support missions (though I'll note that the C models started delivery only a few months before the D and E models which did have bombing capability).

 

[Darthtabby]

I've often seen the B-25J quoted as having a maximum speed of ~275mph (440km/h). However, wwiiaircraftperformance.org has a scan of a 1950 dated document that lists a considerably higher maximum speed of 255 knots (295mph/472km/h) at 15,000 feet for the J model -and that's at Normal Power, not Military Power. That's nearly as fast as the fastest speed I've found listed for later model B-26s (in scans of RAF documentation for the Marauder II and III, also hosted on wwiiaircraftperformance.net).

Does anyone know where that document is from (its a little hard to read the note about that). Or have any other documentation on the B-25J that supports/doesn't support that speed figure? I'm wondering if it could be a matter of the higher figure representing a clean aircraft and the lower representing one with rocket rails or something.

 

[Darthtabby]

Who here has a high degree of familiarity with German engine ratings? I'm trying to calculate the power loading of various aircraft as part of an effort to come up with a workable formula for translating aircraft characteristics into an in game agility stat. But for a lot of German engines I either can't find detailed data or am not sure which part of the data to use. In general I'm trying to find the engine rating most nearly equivalent to Military Power or War Emergency Power. This is easy when the engine is said to have a certain rating with MW-50 that it can maintain for ten minutes, but more difficult when I have a chart of ratings with no time limits specified or in some cases just a single rating under unspecified conditions.

I am particularly interested in early versions of the FW-190's BMW 801. I did find a site with charts for many different DB 601 and 605 variants but only a few of the charts specified the time limits for the various settings.

 

[tomo pauk]

I am particularly interested in early versions of the FW-190's BMW 801. I did find a site with charts for many different DB 601 and 605 variants but only a few of the charts specified the time limits for the various settings.

Perhaps the table might be useful? BMW 801C here: link
Please note that table also have the sections for different ram effect values, IOW the HP vs. altitude at different speeds.
Chart for 'Steig & Kampfleistun' setting (30 min duration) for different ram values for the 801C: link
Also note that both table and chart has values for exhaust thrust (in kg).

A more complete chart for the BMW 801C can be found at the pg. bottom of the pg. 218 of the 'The secret horsepower race' book, 1st edition. Only static values,, ie. no ram effect.

Please note that both table and Calum's chart account for 2550 max rpm with supercharger in high gear for the 801C. However, it seems like that engine was run at 2700 rpm with S/C in high gear during these tests - link - so we might assume that, after winter of 1941/42, the 801C was allowed to do that in service? Going to 2700 rpm improves the altitude power by some margin.

 

[Darthtabby]

Perhaps the table might be useful? BMW 801C here: link
Please note that table also have the sections for different ram effect values, IOW the HP vs. altitude at different speeds.
Chart for 'Steig & Kampfleistun' setting (30 min duration) for different ram values for the 801C: link
Also note that both table and chart has values for exhaust thrust (in kg).

A more complete chart for the BMW 801C can be found at the pg. bottom of the pg. 218 of the 'The secret horsepower race' book, 1st edition. Only static values,, ie. no ram effect.

Please note that both table and Calum's chart account for 2550 max rpm with supercharger in high gear for the 801C. However, it seems like that engine was run at 2700 rpm with S/C in high gear during these tests - link - so we might assume that, after winter of 1941/42, the 801C was allowed to do that in service? Going to 2700 rpm improves the altitude power by some margin.

Thanks Tomo!

Google tells me that Start Und Notsleigstung means "Start and Emergency Service." Since it has a three minute limit I guess that's more or less equivalent to War Emergency Power?

On the DB 601 and 605 engines the highest ratings are generally listed as Höchtsleistung (High Performance) but those sometimes list a one minute limit which makes me question how often they were really used in combat. (Other times the limit is longer, and in other cases its unspecified which really makes me wonder what setting to use for my calculations with those engines.)