Late Me 109 G & K engine settings

[MiloMorai]

Originally posted by Kurfürst
This is for the later G-6s, I am not even sure it speaks of the final version of the GM-1 installment, that become G-6/U2, and some equipment was removed to restore to Center of Gravity to cure the very problem that Milo pointed out about calculations on the prototypes. This plane used a simplified system for GM-1, an UNpressurized, heavy insulated tank mounted behind the pilot.

Earlier 109s used a different system, the GM-1 was mounted in light pressurized LUTZ bottles in the right wing (G-1 and G-3 had this standard, but G-2 and G-4 could be also retrofitted). It was also utilized by the 109 F-4/Z. With GM-1, max. speed was boosted by 120 km/h, making the maximum speed of the Bf 109G well over 700 km/h at altitude, making it the world`s fastest high altitude fighter when it appeared in 1942 - and it remained as such for a good while.

What was removed. A weight I have for a full GM1 system is 195kg/434lb.

There was only 50 G-3s produced.

The only reference I can find on the G-1 with GM-1 is in Prien/Rodeike 109 book which says only the last 80 as lightened high altitude a/c were built. In addition to deletion of the pilot's back armour and the equipment associated with the long range tank, this included an unprotected metal fuel tank and GM-1.

167 G-1s were built.

[Kurfürst]

Indeed Milo, there were hundreds of 109Gs built with built-in GM-1 systems:

unknown? E-7/Z
599 F-4/Z
167 G-1s
50 G-3s
324 G-6/U2

Ca 1100+ aircraft with GM-1. A number of G-2s and G-4s also used the system.

Radinger/Otto`s 109F-K says on page 19, for F-4/Z that : "the fluid was contained in either eight so-called LUTZ bottles or in two circular tanks. Weight of the fluid was either 34 or 42 kg. Weight of the total system was 46 and 75 kg."


As for the TBO time of the late DB 605 Ds, here`s what the DB/DC Motorenkarte says :


After each day's flying.

The fuel and oil pipes on the motor are all checked for security and leaks.
The throttle controls are checked.
A carefull check of the ignition harness and sparkplug performance is emphasised for MW motors. Basically, it says that piston damage will occur if the ignition system is not maintained in top condition.


After 12.5 operating hours

The manifoldpressure sensing pipes are cleaned
The coolant pump gland is greased
Oil in the supercharger control-space is drained
 

After 25 operating hours

The 12.5-hour checks are repeated
Oil and fuel filters are cleaned
Sparkplugs are removed, cleaned and tested
Engine controls are checked and oiled
Propellor is checked for fit and adjustment
A compression test is to be performed
The injectionpump and the supercharger mounting bolts are to be checked for tightness


After 50 operating hours

TEILÜBERHOLUNG (Partial overhaul)

The 12,5 and 25 hr checks are to be repeated
The program calls for a partial overhaul
All components are checked secure fit and function
The starter is checked for correct function


The no. of operating hours for a major overhaul (Grunduberholung) is not noted in the Motorenkarte, but was probably 100 hours.



The anecdotal sources are also of interest :

"I will always stand for the DB engines and German throughness. Generally speaking they were well above avarage and when I had a full running DB 605 on brake test bench in Liberec delegations even from abroad were coming to see it. If they were aircraft experts (and most of them were) they were amazed what a piece of machinery the Germans did create. The RR Merlin was a miscarriage in comparison with the DB, both in design and workmanship."

"Construction of the DB engines were excellent, every detail was considered throughly. To show the difference, when we worked with the other engines our hands were like those of butchers - all blood from the sratches, but when we worked with a DB we had the hands of surgeons... The assembly required a lot of attention - every relevant screw was numbered and destined for a particular place of assembly. Torque wrenches were not used, but screw strain was measured with micron accuracy, the screws were tightened according to one man`s feeling, they were not allowed to overstreched nor loosen but had to be tighten from the very beginning... Don`t believe stories of communist`s sabotage invented by writers - the work was done thorougly till the end of the war."

- Jaroslav Prchal. Came to Avia on February 2, 1944 from Bata`s School of Work to finish his apprenticeship. In the course of time he worked his way up to the brake test bench, where only the most experienced employees were allowed to work. 1


"... It`s a nice feeling, and I like my new plane as well. It`s the 'Blue 11', as a blue no.11 was painted on the fuselage. According to our mechanics, these machines require an engine change after 30 to 40 hours of operation. Of course nowadays it is hard to push the plane around for 30 hours. No practice flights, every take off means a combat sortie - and it is not that simple spending 30 hours in combat without ever bailing out, or making a belly landing. In 30 hours, you can die, get wounded or taken captive. A sortie usually lasts 50 to 60 minutes."

Tobak Tibor : Pumák földön-égen, pg. 220.  ISBN  963 85799 1 9
Lt. Tobak was Bf 109 G-10 pilot at this time with the 101st Fighter Regiment.

[Angus]

My great uncle spent 1200 hrs in the air during ww2. Included there were approx. 500 hrs of combat sorties, Spitfires and P51.
Never was there any engine problem.
Cirkumstances were of all sorts. He flew dozens of missions without the grouncrew touching the aircraft!
I remember Rall mentioning that the DB had a short life and that (after flying a P51) he envied the allies of their robust engine quality.......


oops...a bait

[Kurfürst]

Well Tobak spent 1000+ hours in the 109 alone, but he never had an engine problem either. Only once, his droptank failed to load and jettison, that`s all..

Well do you have an official TBO time for the Merlin?

What I read in Spitfires, Thunderbolts and Warm beer that they changed the radial of the P-47 on every 80 hours or so.

Also, spark plugs had to be replaced after 7-8 hours of operation on the P-51, that practically every sortie.

[MiloMorai]

Originally posted by Kurfürst
Indeed Milo, there were hundreds of 109Gs built with built-in GM-1 systems:

unknown? E-7/Z
599 F-4/Z
167 G-1s
50 G-3s
324 G-6/U2

Ca 1100+ aircraft with GM-1. A number of G-2s and G-4s also used the system.

Radinger/Otto`s 109F-K says on page 19, for F-4/Z that : "the fluid was contained in either eight so-called LUTZ bottles or in two circular tanks. Weight of the fluid was either 34 or 42 kg. Weight of the total system was 46 and 75 kg."

 

That weight I stated was for the fuselage tank GM-1 system. The empty weight was 60kg/134lb. Not much 'boost juice' in the wing system.

Only ~50% of the G-1s had GM-1 and they were unprotected.

So only 324 G-6s out of how many G-6s produced? That is less than 1%.

Only ~ 1/3 of F-4 production had GM-1 coming from 2 batches > WNF > 544 and Erla > 55.

Are you saying all these GM-1 a/c were in service at one time  and they suffered no losses?


Well that statement of German engines must have been early in the war for you must have missed this or was it just ignore?

"Finally, it is not suprising that these engines suffered short-lives, they were hurriedly built and doubtless handled with less than the high standard of care such high performance motors require for a reasonable life-span."

Rather prudent to change the plugs in the P-51 since they spent 75% of their time over enemy territory.

[Kurfürst]

"Only ~50% of the G-1s had GM-1 and they were unprotected. "

Nope, butch says all G-1s and G-3s had built in GM-1 system.

Some of the G-1s were lightened to serve as ultra-high perfromance interceptors. Photorecce planes couldnt shoot back...
Germans produced their own lightened photerecces, the 109G-2/R2s, w/o armor and guns, but with cameras and GM-1. I wonder how they could intercept these planes at 700+ kph.
The best high altitude Spit, the IXHF could do about 670kph, and only a handful of those were built.

Prien Rodeike also notes 'the use of GM-1 was widespread, resulting the G-6/U2".


Well that statement of German engines must have been early in the war for you must have missed this or was it just ignore?

Well Jaroslav Prchal came to Avia on February 2, 1944 from Bata`s School of Work to finish his apprenticeship, it`s only after that he worked on DBs until the end of the war.

Tobak converted to the Bf 109 in the spring of 1944 as well, so both the statements are for the late war German engines.

Are you saying all these GM-1 a/c were in service at one time and they suffered no losses?

One has to be very stupid to conclude this from my post.



Rather prudent to change the plugs in the P-51 since they spent 75% of their time over enemy territory.

Indeed it`s a prudent thing as the engines would otherwise fail. 7-8 hours of spark plug life does not compare well with 50 hours of spark plug life in German engines with MW50. Appearantly the powerplant lifespan problems not only beset the Germans alone.

[Angus]

changing plugs is almost as easy as refuelling.
But piston rings and main bearings,,,,that's some bigger bit.

[pasoleati]

Originally posted by Kurfürst
Well Tobak spent 1000+ hours in the 109 alone, but he never had an engine problem either. Only once, his droptank failed to load and jettison, that`s all..

Well do you have an official TBO time for the Merlin?

What I read in Spitfires, Thunderbolts and Warm beer that they changed the radial of the P-47 on every 80 hours or so.

Also, spark plugs had to be replaced after 7-8 hours of operation on the P-51, that practically every sortie.

Well, Merlin TBO for late war engine 300 hrs in single engined fighters, Allison V-1710 late war TBO, 480 hours.


As for the 80 hrs for the R-2800, I guess they (book authors) had too much beer since standard B-series engines was test run several times  for 100 hrs non stop at 2800 hp (i.e. higher than authorized WER for the B-series).

In Finnish AF service the DB 605 was hard pressed to reach 100 hrs TBO, this despite the Finnish G-2s being limited for the 1.3 ata power setting.

And as you quote from the JaPO book, do also quote those examples where the engines (605D) are replaced after 20-30 hrs of running.

[MiloMorai]

Originally posted by Kurfürst
"Only ~50% of the G-1s had GM-1 and they were unprotected. "

Nope, butch says all G-1s and G-3s had built in GM-1 system.

Not what P&R says.

Some of the G-1s were lightened to serve as ultra-high perfromance interceptors. Photorecce planes couldnt shoot back...
Germans produced their own lightened photerecces, the 109G-2/R2s, w/o armor and guns, but with cameras and GM-1.

I already said that, 80 to be exact.

Prien Rodeike also notes 'the use of GM-1 was widespread, resulting the G-6/U2".

Yet you say only 324 where made. How can 324 be widespread out of the 12,000 or so G-6s made?

Well that statement of German engines must have been early in the war for you must have missed this or was it just ignore?

Well Jaroslav Prchal came to Avia on February 2, 1944 from Bata`s School of Work to finish his apprenticeship, it`s only after that he worked on DBs until the end of the war.

Tobak converted to the Bf 109 in the spring of 1944 as well, so both the statements are for the late war German engines.

Late war as in late 1944 and 1945.

"Are you saying all these GM-1 a/c were in service at one time and they suffered no losses?"

One has to be very stupid to conclude this from my post.

If you gave monthly usage numbers it would be better.

"Rather prudent to change the plugs in the P-51 since they spent 75% of their time over enemy territory."

Indeed it`s a prudent thing as the engines would otherwise fail. 7-8 hours of spark plug life does not compare well with 50 hours of spark plug life in German engines with MW50. Appearantly the powerplant lifespan problems not only beset the Germans alone.

As usual you see what you want to see and ignore the reason why.

[Angus]

So, according to Paseolati, what Rall complained about regarding engine wear seems to be right.
I remember how he put it. He said that after only a couple of flights on a new engine, one could easily turn the prop, while on the p51 it remained stiff after quite a long service.
If this fits, the high speed 109's so often quoted were a rare sight.

[niklas]

What did Rall say exactly?

niklas

[Kurfürst]

Originally posted by pasoleati
Well, Merlin TBO for late war engine 300 hrs in single engined fighters, Allison V-1710 late war TBO, 480 hours.

Care to post a source for this?

Robert Grinsell`s work has to say this on Merlin TBO time :

"The P-51s engine had an overhaul and replacement time of 200 hours, but this was rarely met due to the heavy combat flying of P-51 groups. "



As for the 80 hrs for the R-2800, I guess they (book authors) had too much beer since standard B-series engines was test run several times  for 100 hrs non stop at 2800 hp (i.e. higher than authorized WER for the B-series).

Obviously, the author who flew the P-47 for dozens of missions has no idea what the actual replacement time of the R-2800.

I wonder what Angie has to say on that, he usually places anecdotal evidence on the top, well, or maybe he just does that in selected cases.


And as you quote from the JaPO book, do also quote those examples where the engines (605D) are replaced after 20-30 hrs of running.

Sorry if I hit a nerve pasolati about the TBO times. You can`t seem to bear anything was comparable to the Merlin it seems.

As the Japo book 20-30 hours, I wonder how could you miss Tobak`s statement that the new DB 605Ds of his G-10 had to be replaced after 30-40 hours of operation, which I even highligted in bold.... hard to miss.


Now that on TBO times. I see that our wonderfully balanced article of SpitPartisan site has been updated.

That means, the qoute from butch2k where he stated 1.98ata was cleared in Feb 1945 , and that it was quite certainly put into service was removed. It appears that butch2k is no longer a noted authority on Bf 109s in Mike`s eyes. And of course, 1.98ata performance curves were also removed, the now only existing curves for the 109K-6, the heaviest version (3600 kg vs. 3362kg of the K-4), running at the lowest boost setting.

LOL, that site is a joke.

[MiloMorai]

Originally posted by Kurfürst


LOL, that site is a joke.

What is a joke, is you. You do like to use it for Spitfire reference material, don't you?

You gnash your teeth and wail about MW, yet you post a graph like this:


You accuse MW of using a light colored line for a K-4, yet you do the same thing with the Spit XIV @ 18lb boost with a barely visible line.  You don't include any graph line for a Spit XIV @ 21lb boost. You include a K-4 line with an engine that was never fitted. You show a home made graph that has a K-4 @ 1.98, yet you have never produced any flight test document to prove what you have on your home made graph is indeed true.

Who is the one being the deceitful partisan Barbarossa Isegrim?

No truer words have been said,

"Frankly I can`t imagine how can one spend so much time of research just to make hated plane look bad, when he could do something useful with it...  "

Put into practice your own words.

[pasoleati]

Kurfürst, source for the 300 h TBP for later war Merlin is RRHT book "Merlin Perspective", page 40. The 480 hrs figure is based on Dan Whitney´s Vee´s for Victory. I will check the exact page later tonight.

I am not suggesting the Merlin was a super engine, but it was far better than the DB 605. The latter did have excellent fuel system plus the excellent supercharger drive, but otherwise there were obviosuly too many basic design deficiencies (Merlin´s worst basic design fault was the valve rocker design, i.e. it should have had rollers). For example, most complaints quoted in the JaPO book refer to burnt pistons. I can never understand why the folks at DB chose dry liner construction as it severely hampered heat transfer properties from the piston crown to cylinder walls and finally to coolant. I.e. it is well indicative that e.g. Herrman´s books contain no references to piston problems in the Jumo 213 so the state of German alloys cannot be blamed on this. And the DB is the only major WW Two v-12 liquid cooled engine with dry liners.

This problem was certainly made worse by DB´s decision to obtain high IMEP by adopting high compression ratio. By going to 8.3/8.5:1 in the 605D they pretty well ensured that the peak pressure and thus peak temperature (since the volume can be assumed as relatively constant) was very high, while Junkers and RR adopted low CR giving lower peak p and T for the same IMEP.

One possible means to combat piston crown scorching would have been to direct additional oil cooling flow to the pistons. This could have been best done by mounting crancase (as e.g. Wright did in the R-1820-H) oil jets spraying oil into piston crowns. This would have of course required larger oil cooler, but the effect on piston life would have been considerable.  

JaPo book also mentions some crankpin bearing problems. Again, DB should have copied Jumo´s end oil feed scheme (as Merlin 100 srs and the Griffon had) where all crankshaft and crankpin oil is fed to thru hollow crankshaft. This ensures good oil supply to bearings even at lower oil pressures and low oil pressure seems to have been a problem DB never solved.

All in all, DB´s attitude to the problems with the 605 reming me of Wright´s attitude towards R-3350 problems: cheap fixes were tried when the root cause (in 605´s case: high CR, dry liners, oil feed) should have been investigated and vigorously dealt with.

[pasoleati]

Data on page 332 in Dan Whitney´s book  indicates that all V-1710s were authorized in 1944 for 480 hrs TBO, with 1000 hrs allowed in special cases, whatever the latter are. Anyway, 480 hrs TBO is something that no German WW Two aero engine even dreamed of. Even lower the "tuned" Fafnirs in the Do 17 couldn´t come close.