Powerplants for the Fw 190 / Ta 152

[tomo pauk]

Should've more generally said use of injection systems. If N2O was used, BMW801s used on high altitude recons were able to produce 1,410 hp instead of 868 hp.

Okay, now I get it. Still the 2-stagers are my pets

The 628 had the first stage in front of the engine with a long and curved "ofenrohr" extension to the second stage. Not only does this mean extra weight, it also makes the system much less efficient as compared to e.g. the straight forward Merlin 2-stage system.

I see. The greater engine's displacement can help the lack of efficiency? The 628 did not have the intercooler, so that cancels out the increased weight?
The DB-628 605L do deserve the thread of their own.

 

[bada]

.

I submit the alluded-to Fw 190 / Ta 152 with the BMW 803 would have been an entirely new and larger aircraft that never even made the drawing board, much less had metal cut for it. I would view any suggestion of flying a standard Fw 190 or Ta 152 with a BMW 803 as being unrealistic to say the least, but the potential for a heavy fighter was certainly there, as far as a powerplant goes, when the war ended. Things might have gotten interesting if this dreamed-of fighter had ever gotten into production. Of course, by then, other more advanced piston fighters were flying for other countries and most were rapidly being abandoned for jets. Some were even built and never flown!

I submit the Third Reich would have done the same and concentrated on jets, had it survived past early 1945.

Any comments on the potential future of big pistons in mid-to late 1945 had the war continued?

FW projects:

and yes, most german engineers did drawn mostly new airframes with Jet engines from 44.

 

[Tante Ju]

The 628 had the first stage in front of the engine with a long and curved "ofenrohr" extension to the second stage. Not only does this mean extra weight, it also makes the system much less efficient as compared to e.g. the straight forward Merlin 2-stage system.

Extra weight of what...? The Ofenrohr extension, how much could that - a piece light alloy tube - weight, like, 5 kilos, maybe 10 kilos perhaps? Two stage Merlin installations were a good 2-300 kg heavier than their single stage cousins..

Regardless of the allaged effiency of the "straight forward Merlin 2-stage system", comparing the two stage Merlins to the DB 628 is pointless, since the Merlin was simply not in the same league when it came to high altitude performance...

IIRC the DB 628 simply lost out to the DB 605AS - the 628's extreme performance was simply not required, and the AS engines were simple, instant, minimum risk solutions to the need for better high altitude engines: bolt a DB 603 supercharger to the 605, and ta-daa, problem solved.. hundreds of /AS engined fighters within a few months was a better solution than a couple of dozen uber-high altitude fighters..

 

[Milosh]

There is a thread on this board, re the DB628 engine.
http://www.ww2aircraft.net/forum/engines/daimler-benz-db-628-a-28270.html

 

[tomo pauk]

Extra weight of what...? The Ofenrohr extension, how much could that - a piece light alloy tube - weight, like, 5 kilos, maybe 10 kilos perhaps? Two stage Merlin installations were a good 2-300 kg heavier than their single stage cousins..

Regardless of the allaged effiency of the "straight forward Merlin 2-stage system", comparing the two stage Merlins to the DB 628 is pointless, since the Merlin was simply not in the same league when it came to high altitude performance...

IIRC the DB 628 simply lost out to the DB 605AS - the 628's extreme performance was simply not required, and the AS engines were simple, instant, minimum risk solutions to the need for better high altitude engines: bolt a DB 603 supercharger to the 605, and ta-daa, problem solved.. hundreds of /AS engined fighters within a few months was a better solution than a couple of dozen uber-high altitude fighters..

Agree about the offenrohr being of no concern, weight-wise. The 'extreme performance' was needed, since the Bf-109G with the AS engine was able to top 680 km/h, not enough to catch Merlin Mustang or P-47D. Since Germans were trying out 3 newer 2 stage engines' 'branches', derivatives of Jumo-213, DB-605 and 603, the two stage engines were regarded as needed. But, too little, too late. Contrary to that, DB-628 was there in 1943; the 605AS, no matter how good, starts in mid 1944, while offering less power.

If the LW really did not needed 'uber-high' altitude fighter, why mess with GM-1?

 

[johnbr]

How about the DB-624.

 

[wuzak]

Extra weight of what...? The Ofenrohr extension, how much could that - a piece light alloy tube - weight, like, 5 kilos, maybe 10 kilos perhaps? Two stage Merlin installations were a good 2-300 kg heavier than their single stage cousins..

So, the extra supercharger stage, its housing and its gearing didn't weigh anything?

 

[riacrato]

Extra weight of what...? The Ofenrohr extension, how much could that - a piece light alloy tube - weight, like, 5 kilos, maybe 10 kilos perhaps? Two stage Merlin installations were a good 2-300 kg heavier than their single stage cousins..

Regardless of the allaged effiency of the "straight forward Merlin 2-stage system", comparing the two stage Merlins to the DB 628 is pointless, since the Merlin was simply not in the same league when it came to high altitude performance...

IIRC the DB 628 simply lost out to the DB 605AS - the 628's extreme performance was simply not required, and the AS engines were simple, instant, minimum risk solutions to the need for better high altitude engines: bolt a DB 603 supercharger to the 605, and ta-daa, problem solved.. hundreds of /AS engined fighters within a few months was a better solution than a couple of dozen uber-high altitude fighters..

I'll leave you to your opinion. In mine it's clear the assembly and location of the first stage was very less than ideal and most likely only chosen because of concerns that the airframe might get to "fat" would they mount it in the traditional place: right next to/on top of the second. The way pretty much everyone else did. And the way Daimler Benz also continued to pursue with the DB 605L (and DB 603L) long after the DB 628 was given up on.

So, the extra supercharger stage, its housing and its gearing didn't weigh anything?

~ 140 kg iirc

As far as the "ofenrohr" being of no concern. I'm no engineer and can't explain the physics behind it but the comparable though not similar "extension system" for the Fw 190 V-13 led to a harsh loss in effectiveness of that aircraft's perfomance when compared to the V-15. I'll dig up the numbers later. Granted this is only in part comparable as the Fw 190s in question did not have a two stage supercharger but rather a single stage with or without extension tube behind the air intake, but I would risk a guess and say the effects will be somewhat similar.

 

[Jabberwocky]

Extra weight of what...? The Ofenrohr extension, how much could that - a piece light alloy tube - weight, like, 5 kilos, maybe 10 kilos perhaps? Two stage Merlin installations were a good 2-300 kg heavier than their single stage cousins..

Regardless of the allaged effiency of the "straight forward Merlin 2-stage system", comparing the two stage Merlins to the DB 628 is pointless, since the Merlin was simply not in the same league when it came to high altitude performance...

Two-speed, two stage Merlin installations were about 140-160 pounds/60-70 kg heavier than a single stage engine installation, not two or three hundred kg heavier.

The Merlin 76/77 gave more power than the 628 until about 38000-40000 ft. Maybe not as good at extreme altitudes, but just as good for practical combat altitudes for Ww2. Combat above 40000 ft was exceptionally rare.

 

[Tante Ju]

Two-speed, two stage Merlin installations were about 140-160 pounds/60-70 kg heavier than a single stage engine installation, not two or three hundred kg heavier.

Yet we find the Mark IX Spitfire being some 5-600 lbs heavier than the Mk V (ca 6900 lbs vs 7450 lbs), and the only difference is the installation of the two stage engine. The block may have been just 150 lbs heavier, but the whole installation - no.. the 'straightforward' two stage design needed what was essentially a second supercharger, and intercooler system between the two and a seperate intercooler radiator, larger cooling requirements and so on.

The Merlin 76/77 gave more power than the 628 until about 38000-40000 ft.

I am very sceptical of that given the figures I have seen for these two engines.

Maybe not as good at extreme altitudes, but just as good for practical combat altitudes for Ww2. Combat above 40000 ft was exceptionally rare.

Yes I agree, that is probably why the 605 AS was utilized IMHO, since it was equal or superior to the two stage Merlins at altitude and was much more simplier to install.

 

[Tante Ju]

So, the extra supercharger stage, its housing and its gearing didn't weigh anything?

Allegadly it did not weight anything on Merlins so it seems entirely plausible that it did not weight anything on DBs neither.

Seriously, people get into guesswork instead of simply looking at weight of engines themselves... weight of DB 628 was 860 kg, so between ordinary layout 605 and 603...

 

[wuzak]

Allegadly it did not weight anything on Merlins so it seems entirely plausible that it did not weight anything on DBs neither.

Seriously, people get into guesswork instead of simply looking at weight of engines themselves... weight of DB 628 was 860 kg, so between ordinary layout 605 and 603...

And between the weight of a 2 stage Merlin and a 2 stage Griffon....

Without an intercooler the altitude performance will suffer.

No-one said that the 2 stage system on the Merlin was without weight penalty. Clearly there was - both in the engine itself and the ancillary systems.

 

[GregP]

Sorry guys ... typo. The "222" was supposed to be "211." The 222 WAS developed but there is mo evidence it was ever put into an Fw 190 or a Ta 152.

 

[Shortround6]

Sorry guys ... typo. The "222" was supposed to be "211." The 222 WAS developed but there is mo evidence it was ever put into an Fw 190 or a Ta 152.

real shame about that. It could have been a real boon to the allies if it had been fitted.

 

[tomo pauk]

Neither the 211 was ever fitted in the Fw-190/Ta152.