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Jumo 211N, P, R - looking for some good info
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davebender
1st Lieutenant
Why is that a problem?
DB603 engine height and width were small enough to allow easy fit in a fighter aircraft. Certainly a lot easier then radial engines such as the BMW801 and R2800 which required a large diameter fuselage and considerable space behind the engine for cooling airflow.
DB603 engine height and width were small enough to allow easy fit in a fighter aircraft. Certainly a lot easier then radial engines such as the BMW801 and R2800 which required a large diameter fuselage and considerable space behind the engine for cooling airflow.
Shortround6
Major General
The question is what kind of power can the engine withstand?
For instance, let us say that engine "A" can deliver 1200hp to the prop at 8,000ft. It is using up 100hp in friction (piston rings, bearings, cam followers on camshafts, whatever plus pumps) anad it's supercharger is taking 100hp to run so the engine is actually burning enough fuel to make 1400hp.
Adding a second speed to the supercharger could take another another 100hp so the same strength engine can only deliver 1100hp with the second speed engaged. Adding a second stage could suck up even more power. the engine might only give 950-1000hp at 24,000ft with the second stage engaged. This may give an extra 150-200hp over the original single speed engine but might not be what you are looking for.
Merlins and Allisons with two stage superchargers often had strengthened parts to allow the indicatedHP to up so as to take full advantage of the extra boost available at low altitude. Of course the extra boost can only be used at low altitude if the fuel will allow it.
Junkers engineers may have had choice of working on the 213 or a new supercharger and strengthened parts for a late series 211 but not both at the same time.
If we add a two stage supercharger to the engine to try to get 1200hp at 24,000ft the second stage make take another 100hp to run.
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- #24
wuzak
Captain
Surely a two stage supercharger will require less power to make a given amount of boost at altitude? Or more boost for the same consumed power.
wuzak
Captain
I mean if it replaces the DB601 or DB605 more things will need to change. It won't be a straight swap.
davebender
1st Lieutenant
The Me-109 requires the DB601 / DB605. So complete replacement of the DB601 with the DB603 means replacing the Me-109 fighter aircraft with the Me-309. Or else Fw-190 airframe production doubles and the 20,000 additional Fw-190s are powered by DB603 engines.
I think the Me-309 and Fw-190C (i.e. DB603 engine) would both be bad news for the Allies.
I think the Me-309 and Fw-190C (i.e. DB603 engine) would both be bad news for the Allies.
wuzak
Captain
Wasn't the Me 309 a fialure which had little to do with the engines?
Shortround6
Major General
Tomo "The two stage supercharger should be more effective than a single stage one, ie. consuming less power for same pressure ratio achieved? But I agree that it would've needed more strengthening."
you are both correct. now what altitude are you talking about? An engine that has 1.42-1.45 Ata of manifold pressure can easily get away with a single stage supercharger until 5-6000meters in 1943.
The F4U with it's two stage supercharger had a manifold pressure of 2.0 at it's WER rating at 5150meters and 1.77Ata at Military power at 6360meters. The Merlin 61 was running about 2 Ata at 7150meters.
A single Stage Merlin XX could pull 1.8Ata at 5600meters.
the problem becomes what is your altitude goal. The merlin 61 could be set up to give the same or more power at 5600meters as the Merlin XX. In fact more power to the prop FROM THE SAME CYLINDER PRESSURES would be no problem. Intake charge is heated less (even without after cooler) and so is denser and the compressors actually take less power. Engine does weigh 100-150lbs more though and is longer. again without after cooler.
If you want the 7000meter or up critical altitude, you are going to have to pay for it. Now you need to compress the air more to get the same manifold pressure. you are skating on the very edge of what a single stage supercharger could supply and the two stage is just about mandatory. It will still use less power than a single stage to do the same work but since you are getting more work from it at 7150 meters than you asked at 5600meters you have to put more power into it. you can accept the performance penalty ( which will still give more power than using the standard supercharger at 7150meters) or you can beef up what ever the weakest part/s are and really improve the performance envelope (assuming fuel will support the higher cylinder pressures).
Shortround6
Major General
You can almost guarantee that the 213 required strengthening. the increase in RPM from 2700 to 3250 means about a 45% increase in stress on the pistons, rods, crankshaft and crankcase. And that is if they kept the cylinder pressure the same.
davebender
1st Lieutenant
Not that I'm aware of. The Me-309 had a low development priority and only 4 prototypes were produced before the program was halted. Which is to be expected. The Me-309 required DB603 engines which weren't available historically due to RLM cancelling DB603 engine program funding during 1937 to 1940.
If RLM continues DB603 engine program funding the Me-309 would become a high priority project with perhaps a dozen prototypes flying during 1942. Technical glitches inevitable for any new aircraft type would be solved and the Me-309A would probably be ready for mass production during 1943.
Me-309, Fighter, Luftwaffe
A nice looking aircraft and very fast @ 457 mph.
If RLM continues DB603 engine program funding the Me-309 would become a high priority project with perhaps a dozen prototypes flying during 1942. Technical glitches inevitable for any new aircraft type would be solved and the Me-309A would probably be ready for mass production during 1943.
Me-309, Fighter, Luftwaffe
A nice looking aircraft and very fast @ 457 mph.
Comparing engine lengths between countries can be tricky. The ubiquitous 81in. figure given for the Griffon by almost all source is for the two-stage models and is measured to the airscrew rear cone/collet. Basically the propeller shaft is excluded. The equivalent length for the two-stage Merlin is 78in. The overall length should be about 90-91in. or about three or four inches longer than the Merlin 87-88in. figure commonly given for the two-stage Merlin.
German length figures usually include accessories and the propeller shaft. For the DB 603 A the length is 2610.5mm (102.78in.). This includes the starter. The propeller shaft is 360mm of this. I doubt the starter added much more than 100mm to the length.
German length figures usually include accessories and the propeller shaft. For the DB 603 A the length is 2610.5mm (102.78in.). This includes the starter. The propeller shaft is 360mm of this. I doubt the starter added much more than 100mm to the length.
The Me 309 was killed because it had more engine power but not really more speed than the Bf 109G it was intended to replace. Maneuverability wasn't really better than the 109G as well.
The DB 605 was developed because the 601 reached performance limits with the 601E series (both rpm and boost pressure), the intention was to optimize the 605 for mass-production and mild power increases from increased capacity at similar or slightly higher boost levels (to stay on B4 fuel).
The DB 605 was developed because the 601 reached performance limits with the 601E series (both rpm and boost pressure), the intention was to optimize the 605 for mass-production and mild power increases from increased capacity at similar or slightly higher boost levels (to stay on B4 fuel).
I would discount that. Prototype Me 309 achieved 462 mph. This is way faster than any conceivable Me 109G could achieve even stripped of armament in 1942 when the Me 309 flew this kind of speed. The Me 109 took another 2 years and 3 months to reach 440 mph in October 1944 as the Me 109K4. By that time, if DB603 engine development had of preceded at the same pace as DB605 development something like the DB603EM with 2260hp or more or the DB603LA with the same power at higher altitude would be in widespread use: suggesting an unarmed photoreconaisance Me 309 at that time would be able to achieve close to 500mph. This aircraft had laminar profile wings, the latest radiator technology and latest airframe
technology
The reduction in speed is associated with imposing an very heavy armament of 4 x 20mm canon plus 2 x 30mm canon and then with the use of the weaker DB605. It's fairly obvious that an armament of 3 x 20mm canon would have been quite potent given its layout.
The cliam that it had less manouverabillity also needs look at. Was this with the weaker DB605 all subsequent prototypes were tested with after the first one had been given the DB603.
It seems supply issues of the DB603 were driving the Me 309 to adopt the an engine simply to small for a larger airframe whch then caused the loss in speed.
Manuoverabilliuty can be measured in turning rate or turning radious.
Wing loading of the Me 309 was likely more though its wings may have worked better. Lack of power leads to a reduction in turn radious without loosing height since the power is not there to overcome the extra induced drag. It also leads to a reduction in turn rate. A fast aircraft may have a larger turn radious but a smaller turn rate (as the Me 262 had)
I would say someone didn't support the Me 309, or Messerschmitt company, or Willy Messerschmitt himself. This smells of Erhardt Milch. It is well known that subordinates also tend to write reports that support or underline their bosses views and political objectives. If you want to kill something out of the production program you make sure a bad report is written, subordinates tend to be sensitive to their bosses inclinations.
The Me 309 may have had flaws, I suspect the wing loading may have been somewhat too high but that is something that can be changed by simply scaling up the wing. This is a prototype.
The claims that the Me 309 was little faster than an Me 109 when armament was fitted also are worth looking at. The Armament proposed seems to have
been just over the top.
I do not believe that the DB601E was at its development limits; If the DB605 could eventually achieve 1.99 ata boost then the slighly smaller and certaiblty lighter DB601 could as well.
The problems that plagued the DB605 incluided a lubrication issue didn't seem to trouble the DB601. The advances that improved DB605 performance such as better spark plugs could have been applied directly to the DB601. Enlarged superchargers. I rather think that all of the time an effort spent in designing the DB605 could have gone into refining the DB601.
When the DB605 debut in service with the Me 109G1 around may 1942 its was hardly an improvement over the Me 109F4, the engine was not any more powerfull at all except at high altitude: that could have been achieved just by fitting a larger more capable supercharger.
Moreover the DB601 continued use keep weight down so the Me 109 airframe does not develop draggy bulges over the wheels and it does not loose its retractable tail wheel.
Shortround6
Major General
I am not sure that the weight of the 605 was all that much greater than the weight of 601 with accessories and as installed.
If you want the big blower from the 603 on an improved 601 you have to take the weight and bulk just like the 605 did.
If you want 1800-2000hp the engine has to stressed to withstand it.
Changing the bore by 4 mm and keeping the same bore centers shouldn't change the weight of the engine all that much on it's own.
If you want the big blower from the 603 on an improved 601 you have to take the weight and bulk just like the 605 did.
If you want 1800-2000hp the engine has to stressed to withstand it.
Changing the bore by 4 mm and keeping the same bore centers shouldn't change the weight of the engine all that much on it's own.
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- #36
The quirk with the DB 605 is that it went with it's 'Notleistung' approved, and then restricted several times in 1943, finally approved from October of 1943. The usage in the Bf-109 was further compromised with the plane having fixed tail wheel, plus the bulges in the engine cowling, starting with 109G-6; the additional cannons made the issue further complicated. No wonder than, with all of these draggy items, the G-6 was slower than 109s of 1942 - not that a good idea with Allies introducing the planes with ever increasing performance.
Maybe the best 109 for 1943 would include DB-601E, no hull MGs at all, with engine cannon and 2 gondola cannons, retractable tailwheel? Still very much competitive at Eastern front, with good punch to kill the 4-engined jobs. The proper fighter with DB-603A would've surely come in handy, some time in 1943. As big as Spitfire XIV, with internal cannons and good fuel quantity, of course.
Maybe the best 109 for 1943 would include DB-601E, no hull MGs at all, with engine cannon and 2 gondola cannons, retractable tailwheel? Still very much competitive at Eastern front, with good punch to kill the 4-engined jobs. The proper fighter with DB-603A would've surely come in handy, some time in 1943. As big as Spitfire XIV, with internal cannons and good fuel quantity, of course.
davebender
1st Lieutenant
That misses the point. The fate of German aircraft programs was largely decided by engine availability.
Me-109 was designed for DB601 / DB605 engine.
Me-309 was designed for DB603 engine.
The Me-309 cannot enter mass production unless RLM funds production of more DB603 engines. The Me-109 cannot remain in mass production unless RLM funds continued production of the DB605 engine (or perhaps that elusive Jumo 211R engine).
The He-100 and Fw-187 were in a similiar position during 1939 to 1940. No matter how good or bad the designs they could not enter mass production because Genshagen DB601 engine factory funding was cut from 50 million RM to 20 million RM during October 1935.
davebender
1st Lieutenant
I suspect that has a lot to do with the Me-109 and DB605 engine being produced to the end of the war.
Most German combat (including aerial combat) was on the Eastern Front. The Me-109 performed superbly in Russia. JG52 was equipped with Me-109s for the entire war and they claimed over 10,000 kills. Pilots such as Erich Hartmann and Günther Rall had no desire to switch to a different aircraft type. Erich Hartmann even turned down a chance to fly Me-262s towards the end of the war.
If it had entered mass production I think the larger, faster and more heavily armed Me-309 would have been ideal for fighting American bomber formations. But the Me-109 would still be king of the Eastern Front.
Most German combat (including aerial combat) was on the Eastern Front. The Me-109 performed superbly in Russia. JG52 was equipped with Me-109s for the entire war and they claimed over 10,000 kills. Pilots such as Erich Hartmann and Günther Rall had no desire to switch to a different aircraft type. Erich Hartmann even turned down a chance to fly Me-262s towards the end of the war.
If it had entered mass production I think the larger, faster and more heavily armed Me-309 would have been ideal for fighting American bomber formations. But the Me-109 would still be king of the Eastern Front.
By Erich Hartmanns own account, his turning down the chance to fly the Me262 in combat had nothing to do with the aircraft itself. He did not want to leave or abandon the unit or men he had fought beside for years.
Gunther Rall had some scathing remarks about the Fw190, that it was the crate the Me109 was shipped in, or something similiar to that.
Gunther Rall had some scathing remarks about the Fw190, that it was the crate the Me109 was shipped in, or something similiar to that.
