which 109 came first?

[gripen]

Originally posted by Knegel

I also wonder if the DB605A and the propeller still was the same in mid/late 1943, like in mid/late 1942. This would have been a very long stop in succesfull development, at a time where germany still had all advantages.

The standard propeller for the low altitude Bf 109G (DB 605A) variants was generally the same all the time (VDM/9-12087). Only the later high altitude variants had another propeller; in fact the high altitude tests with GM-1 were conducted with the 12087 at 1943.

There were at least three series of DB 605A (Baureihe 0, 1 and 2) in addition the Italian built DB 605A engines were somewhat different. Anyway, the output was pretty much constant all the time at given map/rpm combination. The early DB 605A for the G-1 and G-2 was designated as the 9-605-2008 and the later for the G-6 as the 9-605-2040.

Originally posted by Knegel
...since the WEP for at least the G2 never was cleared (the FAF did dissable this permanent for all MTīs)...

Most of the Bf 109Gs (G-2s, G-6s etc) of the FAF arrived 1,42ata/2800rpm setting disabled. Only the last G-6s, which arrived summer 1944, had the the setting enabled when arrived. It seems that the setting was cleared for the service use some time spring or summer 1944.

Originally posted by 1K3

109F-4 as a 1941 plane did not use WEP until 1942.

So far I have not seen direct evidence that the 1,42ata/ 2700rpm setting for the DB 601E was actually cleared for service use. One of the principal differences between the DB 601E and the DB 605A was that in the case of the DB601E only the exhaust ports were cooled but in the case of the DB605A also the intake ports were cooled, in addtion the overall head cooling was improved due to larger coolant channels. So it's quite unlikely that higher rating was allowed for the DB 601E.

gripen

[Knegel]

Hi gripen,

the DB605 maybe have had a better cooling system, but it also was a more big engine, which had more power in general.

Afaik the problems of the DB605A was related to the velve seat, while the DB601A and E got problems due to detonations and main overheat problems, due to not enough radiator area and high rpm(the DB605A had  as much power as the DB601E with 100 rpm less, for a longer time to a higher alt).

The Start/Not of the DB601E got used in most 109F tests i saw, unlike to the 109G-1/2 tests! I cant find a hint that it wasnt cleared in 1942.

But anyway, what most people dont seems to see, is that Start/Not is what it is! Its good to escape, but while combat and climb the pilots normaly didnt use it.

Would be cool if we could get a speed and altitude(temperature) related time to overheat in AH, in addition to the rpm related influence.

Greetings,

Knegel

[gripen]

Originally posted by Knegel

the DB605 maybe have had a better cooling system, but it also was a more big engine, which had more power in general.

There is 4mm difference in bore (150mm vs 154mm) resulting a bit over 5% difference in the volume so the difference in the size is pretty much neglible.

The difference in the size of head cooling channels seems to be around 50%.

Originally posted by Knegel

Afaik the problems of the DB605A was related to the velve seat...

Start and emergency power in the DB 605A caused burned pistons and over heating; typical head cooling related problems.

There is plenty of documentation listing 1,42ata/2800rpm rating for the DB 605A from 1942 onwards despite it's known that the rating was not used. The same is probably true for the DB 601E; if the rating is listed, it does not mean that it was used.

gripen

[Charge]

"Start and emergency power in the DB 605A caused burned pistons and over heating; typical head cooling related problems."

I'd say that those symptoms are typical for knocking i.e. too high boost or too lean mixture, but of course a vastly underrated cooling of heads could cause this kind of effects but that could rather cause other problems too. E.g. continous failure and breakage of sparkplugs or valves. Additional cooling of heads could help but the cooling capacity should be very much better to have much effect on knocking. That is my impression.

-C+

[1K3]

(kinda off topic but...)

If 109g-2 did not use WEP in 1942 then that explains why the Germans feared the P-39s at low alt in the eastern front.  Soviet aces were racking up kills in that foreign fighter.

[Denniss]

Originally posted by gripen


So far I have not seen direct evidence that the 1,42ata/ 2700rpm setting for the DB 601E was actually cleared for service use. One of the principal differences between the DB 601E and the DB 605A was that in the case of the DB601E only the exhaust ports were cooled but in the case of the DB605A also the intake ports were cooled, in addtion the overall head cooling was improved due to larger coolant channels. So it's quite unlikely that higher rating was allowed for the DB 601E.

gripen [/B]

Then please tell me what's this:
http://hometown.aol.co.uk/JStirlingBomber/DCP_0121.jpg

"The three minute emergency engine limitations for the engine as given by the card do agree with those from other sources and are:
Boost: 1.42 ata
R.P.M: 2,700

If the cruising speeds given are correct, extrapolation to the emergency output would suggest that the maximum level speed of the aircraft is in excess of 400 m.p.h at about 23,000 ft

[Viking]

Originally posted by gripen
Most of the Bf 109Gs (G-2s, G-6s etc) of the FAF arrived 1,42ata/2800rpm setting disabled. Only the last G-6s, which arrived summer 1944, had the the setting enabled when arrived. It seems that the setting was cleared for the service use some time spring or summer 1944.

The 109s the FAF got were second hand. Most were tired and some had been damaged. That the engines were de-rated should not come as a surprise; the LW often de-rated older engines and used them in second line aircraft. This is why the FAF experiences with the 109 should not be considered compatible with LW experience. Although the 109s served the FAF well, the FAF 109s were not kept to the standard of LW frontline 109s.

Originally posted by gripen
There is 4mm difference in bore (150mm vs 154mm) resulting a bit over 5% difference in the volume so the difference in the size is pretty much neglible.

The difference in the size of head cooling channels seems to be around 50%.

It was enlarged to 35.7 liters and improvements allowed an increase in the maximum permissible rpm. Altered valve timing increased the inlet period and improved the scavenging to give greater volumetric efficiency at higher rpm. A complete redesign of the cylinder block obtained the maximum possible bore with existing cylinder centers. The crankshaft big-end bearings were also modified.

[BlauK]

Originally posted by Viking
The 109s the FAF got were second hand. Most were tired and some had been damaged. That the engines were de-rated should not come as a surprise; the LW often de-rated older engines and used them in second line aircraft. This is why the FAF experiences with the 109 should not be considered compatible with LW experience. Although the 109s served the FAF well, the FAF 109s were not kept to the standard of LW frontline 109s.
 

The First 15 (or 16) FAF Bf109G2:s were newly built, the next 15 (or 14) were factory repaired, but still similarily fully functional!
IIRC, the FAF flight tests actually show better performance than some german test... the tests naturally depend much on weather conditions etc.


The reason, why FAF prohibited 1.42 ata, was the small number of available planes. They simply needed as many hours from the engines as possible. There was lack of spare engines and also, a plane is not very effective fighter when it lies in a hangar being serviced.

The last 109G6:s still flew in FAF in 1950's .. the very last in 1954

[gripen]

Originally posted by Viking
That the engines were de-rated should not come as a surprise; the LW often de-rated older engines and used them in second line aircraft.

According to German Bf 109G manuals, the 1,42ata/2800rpm rating was not allowed as late as spring 1944. As BlauK noted, the FAF planes were partially new and partially factory overhauled. The replacement engines came through normal LW supply, basicly same engines as used by LW units in the Lappland.
 

Originally posted by Viking

It was enlarged to 35.7 liters and improvements allowed an increase in the maximum permissible rpm. Altered valve timing increased the inlet period and improved the scavenging to give greater volumetric efficiency at higher rpm. A complete redesign of the cylinder block obtained the maximum possible bore with existing cylinder centers. The crankshaft big-end bearings were also modified.

The volume difference between 33,9l and 35,7l is 5,1 or 5,4% depending which way you calculate it. Large part of the other differences were due to needs of mass production (like crankshaft bearings and connecting rod design and bearings overall).

Originally posted by BlauK
The reason, why FAF prohibited 1.42 ata, was the small number of available planes. They simply needed as many hours from the engines as possible.

The 1,42ata was disabled by Germans when delivered until summer 1944. Once the planes started to arrive with the setting enabled, some were used with it enbaled while in the others the setting was disabled by FAF (the planes which arrived with 1,42ata are known as well as which were used by FAF with that setting).

gripen

[Knegel]

Originally posted by gripen
There is 4mm difference in bore (150mm vs 154mm) resulting a bit over 5% difference in the volume so the difference in the size is pretty much neglible.

The difference in the size of head cooling channels seems to be around 50%.

 

Start and emergency power in the DB 605A caused burned pistons and over heating; typical head cooling related problems.

There is plenty of documentation listing 1,42ata/2800rpm rating for the DB 605A from 1942 onwards despite it's known that the rating was not used. The same is probably true for the DB 601E; if the rating is listed, it does not mean that it was used.

gripen

The main point i was up to make clear is that you cant compare the DB605A with the DB601E regarding overheat problems.

Every engine started to cause burned pistons at WEP setting, thats why its called WEP. Afaik the bigger problem was that even when the times to be used was very low, so no piston could burn, the velve seats tended to take damages.

My point was that the DB601E run on higher rpm and ata to produce similar power than the DB605A had. It dont matter how much bigger the engine was, the fact that it did produce more power at less ata and rpm is the point.

Afaik the problem of the DB601E was the missing cooling in general, not the detonations, which are normal for engines running to long on WEP.

Greetings,

Knegel

[Viking]

Originally posted by BlauK
The reason, why FAF prohibited 1.42 ata, was the small number of available planes. They simply needed as many hours from the engines as possible. There was lack of spare engines and also, a plane is not very effective fighter when it lies in a hangar being serviced.

Yes, that's also what the LW did to their second line units, especially on the Russian and Norwegian fronts and with Jabo units.

Originally posted by gripen
According to German Bf 109G manuals, the 1,42ata/2800rpm rating was not allowed as late as spring 1944. As BlauK noted, the FAF planes were partially new and partially factory overhauled. The replacement engines came through normal LW supply, basicly same engines as used by LW units in the Lappland.

I'm sure some 109G manuals state that the 1.42 ata was not allowed. It all depends which unit operated that particular 109G. Many if not most 109s on the Russian front flew with de-rated engines because of the logistical nightmare. They needed every hour they could get out of the engine. The Eismeerjager also flew with mostly older second line fighters and de-rated engines due to increasing logistical difficulties. This is of course far from the plight of the pilots flying in Reichsverteidigung units who needed every ounce of power from their machines just to survive. All new engine modifications and boost settings were always tested by the defense units first, and they often flew with higher boost settings than were officially allowed.

[Denniss]

Originally posted by gripen
According to German Bf 109G manuals, the 1,42ata/2800rpm rating was not allowed as late as spring 1944.

Do you have a specific date for this ?
And also does this date belong to the issue of the manual (Handbuch Ausgabe Januar 1944) or to the date of the latest revision (Handbuch Stand Januar 1944)  ?

[Bodhi]

Originally posted by Krusty
Don't use wikipedia. Ever.

Why shouldn't he use wilkipedia... You make up stuff all the time, why shouldn't it be ok for others to make up stuff too?

[1K3]

oh BURN!:D

[gripen]

Originally posted by Denniss
Do you have a specific date for this ?
And also does this date belong to the issue of the manual (Handbuch Ausgabe Januar 1944) or to the date of the latest revision (Handbuch Stand Januar 1944)  ?

I don't have the manuals in hand but at least the Bf 109G-8 manual claims the restriction at spring 1944. The DB 605 engine card (DB 605 A-B Baureihe 0,1 u.2 Motoren-Karte, Stand April 1944, Ausgabe Juli 1944) has no restrictions claimed.

Elsewhere is claimed that the restriction was removed sometime autumn 1943 but at least FAF started to receive planes with 1,42ata enabled summer 1944.

gripen