# A superior German fighter



## bob44 (Jun 1, 2013)

I cannot find the German pilot who said something like - before the BOB, the 109 was vastly superior to any other fighter. After fighting the Spitfire, we (Germans) need something much better than the 109 and 190. A jet fighter.
What could the Germans have done before the BOB to get a jet fighter into use?
Assuming hitler would give this order.


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## davebender (Jun 1, 2013)

Nothing. Not even Jumo 004A engine could have been mass produced that early.


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## DonL (Jun 1, 2013)

bob44 said:


> I cannot find the German pilot who said something like - before the BOB, the 109 was vastly superior to any other fighter. After fighting the Spitfire, we (Germans) need something much better than the 109 and 190. A jet fighter.
> What could the Germans have done before the BOB to get a jet fighter into use?
> Assuming hitler would give this order.



The Bf 109F-4 was better or equal to the Spitfire V
The FW 190A outclassed the Spitfire V at 1942
A Fw 187 with two DB 601A1 would have outclassed a Spitfire MK II and V at Speed, dive, range and arnament. With two DB 601F (1350PS), it would had outclassed the Spitfire IX from speed, dive, range and arnament.

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## VBF-13 (Jun 2, 2013)

DonL said:


> The Bf 109F-4 was better or equal to the Spitfire V
> The FW 190A outclassed the Spitfire V at 1942
> A Fw 187 with two DB 601A1 would have outclassed a Spitfire MK II and V at Speed, dive, range and arnament. With two DB 601F (1350PS), it would had outclassed the Spitfire IX from speed, dive, range and arnament.


The Luftwaffe did reasonably well against the Spitfires. Germany just didn't have the staying power the U.S. had to make new aircraft that would make a turkey shoot out of those confrontations.


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## DonL (Jun 2, 2013)

VBF-13 said:


> The Luftwaffe did reasonably well against the Spitfires. Germany just didn't have the staying power the U.S. had to make new aircraft that would make a turkey shoot out of those confrontations.



No FW 187 with DB 601 F or DB 605A wouldn't be ever a turkey shoot to any USAAF fighter! Even a a P 51 H would have had a hard time to bring down a FW 187 whith DB 601 F engines and a high speed of 680km/h/altitude 7000m at 1942. Also the FW 187 was much better to the sticks as any Bf 109 at high speed! It wasn't only the numbers and fuel, the Bf 109G was dead meat at the West since 1943/44 and the quality of the Bf 109G was average to worse from performance and reaction to the sticks for nooby pilots!


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## VBF-13 (Jun 2, 2013)

DonL said:


> No FW 187 with DB 601 F or DB 605A wouldn't be ever a turkey shoot to any USAAF fighter! Even a a P 51 H would have had a hard time to bring down a FW 187 whith DB 601 F engines and a high speed of 680km/h/altitude 7000m at 1942. Also the FW 187 was much better to the sticks as any Bf 109 at high speed! It wasn't only the numbers and fuel, the Bf 109G was dead meat at the West since 1943/44 and the quality of the Bf 109G was average to worse from performance and reaction to the sticks for nooby pilots!


Do you mind if I say something, while you, um, catch your breath? You don't have to shout, Don. I hear you. In fact, wasn't one of the purposes of the around-the-clock bombings to put the Luftwaffe to those stresses? I'll defer to your technical expertise on those engines, as I wouldn't rightly know.


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## altsym (Jun 2, 2013)

DonL said:


> the Bf 109G was dead meat at the West since 1943/44


In what respect was it 'dead meat'?


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## DonL (Jun 2, 2013)

The Bf 109 G series suffered heavy issues!
The DB 605 was deficient and was far away from a reliable engine 1942/43 and was cleared to emergency power at the end of 1943.
This wasn't only a fault of Daimler Benz, because the fuselage of the Bf 109 G wasn't able to create enough cooling for the DB 605. Read the report of Prof. Neilinger and the issues between the DB 605 and the Bf 109G. Also the Bf 109 G series was a step *back* from aerodynamics compare to the Bf 109 F-4 with all that bulges and especially the Bf 109 G6 with the two gondulas under the wings was dead meat to any allied escort fighter like the P47, P38 and P51.

The Bf 109 G series and especially the Bf 109 G6 with the two gondulas under the wings was a bitch to fly, from after action reports of skilled german pilots.
The Bf 109 G series wasn't any easy a/c for new pilots, it was very hard for the noobies to handle the worse stick control at high speed and also to defend their a/c against any Allied escort fighter. You can't compare Experten with hundreds of sorties and very very skilled handling capabilitys to a nooby fresh out of the training school.


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## tyrodtom (Jun 2, 2013)

And a nooby right out of flight school is going to do better in a more complex twin engined fighter ??


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## DonL (Jun 2, 2013)

Why more complex?

Every german a/c from Bf 109, Bf 110, FW 190, Ju 88 and Fw 187 was controlled to a single handled power stick.
There were no issues with fuel mixes or prop pitches (it was automatic handled from the a/c) 
From all after action reports to FW a/c's (this incuded the FW 187 at it's sorties at Norway and Denmark), FW a/c's were much easier to handle at high speeds compare to Messerschmitt a/c's. The stick controls were easy to handle even at 550km/h and above.


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## Civettone (Jun 2, 2013)

DonL said:


> No FW 187 with DB 601 F or DB 605A wouldn't be ever a turkey shoot to any USAAF fighter! Even a a P 51 H would have had a hard time to bring down a FW 187 whith DB 601 F engines and a high speed of 680km/h/altitude 7000m at 1942. Also the FW 187 was much better to the sticks as any Bf 109 at high speed! It wasn't only the numbers and fuel, the Bf 109G was dead meat at the West since 1943/44 and the quality of the Bf 109G was average to worse from performance and reaction to the sticks for nooby pilots!


How can you know the Fw 187 would be superior to them? Are there any test reports which show this? How do you know it would dive faster than a Spitfire IX? How do you know the Fw 187 would be more easy to handle once it had doubled its engine power? 

That the Bf 109G was "dead meat" in 1943/1944 is a great exaggeration. It was still a deadly foe and was loved by those who flew it and feared by those who opposed it. It may have been difficult to fly for recruits but there were many great planes which were unforgiven for the inexperienced. The Bf 109G was essentially the same airframe as the Bf 109F which was considered to be a very fine and responsive plane to fly. 

Kris


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## OldSkeptic (Jun 2, 2013)

DonL said:


> The Bf 109 G series suffered heavy issues!
> The DB 605 was deficient and was far away from a reliable engine 1942/43 and was cleared to emergency power at the end of 1943.
> This wasn't only a fault of Daimler Benz, because the fuselage of the Bf 109 G wasn't able to create enough cooling for the DB 605. Read the report of Prof. Neilinger and the issues between the DB 605 and the Bf 109G. Also the Bf 109 G series was a step *back* from aerodynamics compare to the Bf 109 F-4 with all that bulges and especially the Bf 109 G6 with the two gondulas under the wings was dead meat to any allied escort fighter like the P47, P38 and P51.
> 
> ...



Well said, the 109F was the pinnacle of the design without significant aerodynamic and structural changes. They desperately needed to do a major upgrade (like the Typhoon to Tempest conversion, or the 190A to Dora).

The single biggest problem was that it was so small. it was the smallest and lightest of the fighters in the ETO.

While this was a significant advantage in 39/40/41/part of 42, after that the airframe was too small for the extra power and weapons needed to be competitive.
Therefore the aerodynamics started to get severely compromised making the plane unable to really utilise the extra power available.
Plus, it made what was a moderately difficult plane for a beginner to fly and fight effectively, into something more difficult. And given the attrition the Luftwaffe was suffering it needed something that was far far easier for the newbies to be able to utilise more effectively.

Kurt Tank did it with the 190, apart from its nasty high speed stall characteristic (something shared with the Mustang) it was by all accounts an easy plane to fly.

A crash program to stretch the fuselage and have a larger wing (and sorting out the ailerons and elevator issues), would have produced a far better plane for that later period, especially for the higher altitude work, capable of really absorbing and using the extra power that was becoming available. 

Willy Messerschmitt and his team really did a great job designing it, but there are some parallels with the Zero in that there were compromises in the design that ultimately limited it. And, for some unknown reason (at least to me), they were unwilling to make a sensible upgrade.

Part of the issue was that they were more aerodynamically conservative than Supermarine (but much less than Hawker of course).
The way they achieved its (in 39/40/41) excellent performance was to make it as small and light as possible and have a higher wing loading (with the reduced drag), squaring the circle by using slats.

But it left less expansion room for larger and more powerful engines and weapons, plus the aerodynamics were less capable of absorbing them.


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## riacrato (Jun 2, 2013)

Making the Bf 109 fuselage longer and the wings wider means more weight and more drag for the same engine power. The last thing the 109 needs in 1943-44 is to fall behind (even more) in level speed when it was already somewhat slower than its contemporaries from the G-6 model on.

To compensate you'd need a more powerful engine such as the DB 603 or Jumo 213... for which the FW 190 is the far more sensible airframe.

The Bf 109 should've gotten some of its refinements earlier and (if possible) be phased out more and sooner in favour of the FW 190 and derivatives. It was still okay for the west, especially the very late marks, and definetly competetive in the east until the very end.


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## wiking85 (Jun 2, 2013)

OldSkeptic said:


> Well said, the 109F was the pinnacle of the design without significant aerodynamic and structural changes. They desperately needed to do a major upgrade (like the Typhoon to Tempest conversion, or the 190A to Dora).
> 
> The single biggest problem was that it was so small. it was the smallest and lightest of the fighters in the ETO.
> 
> ...



https://de.wikipedia.org/wiki/Messerschmitt_Me_209
They spent their development efforts on the failed 209 and 309 versions, only to abandon them when the Ta-152 project proved superior to the RLM; then there was just jet engines and the Me262, which offered far better performance for what was needed, bomber killing, than any piston fighter upgrade.
The Me109 was at the end of its design limits by 1943, so needed a totally new version like a 209 with a totally redesign.
Of course you forgot the K-series of the 109 too, which brought back and upgraded the qualities of the F-series compared to the G:
https://en.wikipedia.org/wiki/Messerschmitt_Bf_109_variants#Bf_109K


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## Civettone (Jun 2, 2013)

The Bf 109G/K remained competitive til the very end. It was not an easy aircraft to fly but not bad enough to stand in the way of great achievements. We have had numerous discussions about the handling of the late versions, but I still haven't found proof that it was _too_ difficult to fly. Sure its controls froze up at maximum speed, but other than that, it was a mean killing machine able to stand up to anything the Allies threw at it until the last day of the war, and would have remained competitive for another year or two. The bad reputation came from Allied test pilots who did not know how to handle the Bf 109, or who are simply idiots (i.e., Kit Carson), or comes from the many accidents by hardly trained pilots who should never have been allowed in the cockpit.

Kris


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## Mike Williams (Jun 2, 2013)

DonL said:


> [...] Read the report of Prof. Neilinger...[...]



Hi DonL, Can you please provide the source for Prof. Neilinger's report, preferably primary?

Thanks.


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## drgondog (Jun 2, 2013)

DonL said:


> The Bf 109F-4 was better or equal to the Spitfire V
> The FW 190A outclassed the Spitfire V at 1942
> A Fw 187 with two DB 601A1 would have outclassed a Spitfire MK II and V at Speed, dive, range and arnament. With two DB 601F (1350PS), it would had outclassed the Spitfire IX from speed, dive, range and arnament.



DonL - why so sure the Fw 187 could out dive a Spit IX? What distinction about the wing and associated onset compressibility delay would have made this possible? 

don't see the airfoil but wonder what the T/C ratio was as well as the behavior of a substantial part of the wing immersed in prop vortex..


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## tyrodtom (Jun 2, 2013)

DonL said:


> Why more complex?
> 
> Every german a/c from Bf 109, Bf 110, FW 190, Ju 88 and Fw 187 was controlled to a single handled power stick.
> There were no issues with fuel mixes or prop pitches (it was automatic handled from the a/c)
> From all after action reports to FW a/c's (this incuded the FW 187 at it's sorties at Norway and Denmark), FW a/c's were much easier to handle at high speeds compare to Messerschmitt a/c's. The stick controls were easy to handle even at 550km/h and above.



I've looked at several pictures of Bf110 and Ju88 cockpits, maybe i'm looking at older versions, but I only see the usual twin engine grouping of dual controls for the engines, pitch, mixture , ect., no single power lever.
One comment on the Ju88 cockpit, not all that many gauges for a twin, but one of the most spead out instrument panels i've seen, you'd be in danger of giving yourself vertigo just from swiveling your head to scan them.


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## VBF-13 (Jun 2, 2013)

OldSkeptic said:


> Well said, the 109F was the pinnacle of the design without significant aerodynamic and structural changes. They desperately needed to do a major upgrade (like the Typhoon to Tempest conversion, or the 190A to Dora).
> 
> The single biggest problem was that it was so small. it was the smallest and lightest of the fighters in the ETO.
> 
> ...


I'm a lost ball in the tall weeds, but this much I do get. Germany was in much the same spot with its air program and its aircraft as Japan, and at around the same time, and for much the same reasons. And it was facing an opponent who, by stark contrast, was over-designing and over-building. Let me just add, too, we refer to this as the "ETO." That's bullshit. This war, once it really got going, was on Germany's home turf. For that reason, in itself, it had it even harder than Japan.


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## tomo pauk (Jun 2, 2013)

VBF-13 said:


> I'm a lost ball in the tall weeds, but this much I do get. Germany was in much the same spot with its air program and its aircraft as Japan, and at around the same time, and for much the same reasons. And it was facing an opponent who, by stark contrast, was over-designing and over-building. Let me just add, too, we refer to this as the "ETO." That's bullshit. *This war, once it really got going, was on Germany's home turf.* For that reason, in itself, it had it even harder than Japan.



Re. bolded part: what year do you have in mind, when the war 'really got going'?


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## altsym (Jun 2, 2013)

VBF-13 said:


> Let me just add, too, we refer to this as the "ETO." That's bullshit. This war, once it really got going, was on Germany's home turf. For that reason, in itself, it had it even harder than Japan.


German Regular Army the Luftwaffe were still all over Europe when Germany surrendered. 

@ DonL; As far for the 109 being 'dead meat', hardly. It was a deadly foe right until the end.


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## davebender (Jun 2, 2013)

IMO Fw-187 would have been best fighter aircraft in the world during 1940 bar none. And it was production ready.

However the original question concerned getting a jet into combat during BoB.


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## altsym (Jun 2, 2013)

Oh yah lol. IIRC the 262 V1/2/3 was available during the BoB, engine availability was the problem. Somehow, Jumo would have to produce a lot more engines to make the 262 viable. Flak gets everything sooner or later. How many hours were those early jet engines good for?


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## Milosh (Jun 2, 2013)

altsym said:


> Oh yah lol. IIRC the 262 V1/2/3 was available during the BoB, engine availability was the problem. Somehow, Jumo would have to produce a lot more engines to make the 262 viable. Flak gets everything sooner or later. How many hours were those early jet engines good for?



The flight flight of the Me262V1 was on *18 April 1941*. BoB had been over for a few months.


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## Civettone (Jun 2, 2013)

You could build twice as many Bf 109Es with the limited amount of DB 601s available. That means you go to war with only half the fighter force. I think I would stick with the Bf 109E ... which at the time was the best fighter plane in the world. 

Of course Dave, I know you are going to say that they should have given full priority to a massive DB 601 or even 603 production schedule ... 

Kris


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## davebender (Jun 2, 2013)

You don't need a massive effort. Just stick to original DB601 engine production plan before funding was cut from RM 50 million to RM 20 million. That should give you twice as many DB601 engines during 1939.


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## DerAdlerIstGelandet (Jun 2, 2013)

Civettone said:


> You could build twice as many Bf 109Es with the limited amount of DB 601s available. That means you go to war with only half the fighter force. I think I would stick with the Bf 109E ... which at the time was the best fighter plane in the world.
> 
> Of course Dave, I know you are going to say that they should have given full priority to a massive DB 601 or even 603 production schedule ...
> 
> Kris



We may have disagreed on many things, but this is not one of them.


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## Civettone (Jun 2, 2013)

I remember you saying that the funding went to the Jumo 211 plants instead. Cutting their funds would probably mean less bombers. As much as I like the Fw 187, I find it difficult to support its production. Germany needed large numbers of aircraft. And for that reason, they were right to stick to what was in production and which was at least as good as anything the Allies had.


Kris


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## Milosh (Jun 2, 2013)

How many engines had to be produced to support the number of a/c in service? ie how many spares?


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## VBF-13 (Jun 2, 2013)

tomo pauk said:


> Re. bolded part: what year do you have in mind, when the war 'really got going'?


Well, when did it start? It started well-before the Allies got in there on the ground. It started with the bombing missions. Once those got going, the fight was in Germany's corner. And it didn't let up.

EDIT...



altsym said:


> German Regular Army the Luftwaffe were still all over Europe when Germany surrendered.


Definitely. But let's not neglect the significance of Germany in itself being a front. That only compounded its inability to lick its wounds. The more those bombing missions escalated, the more so.


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## GregP (Jun 2, 2013)

I see DonL is going to design a new twin from the Fw 187, with heavier engines, never built, and state that it would not be outclassed by anything, despite that fact that, except for the Mosquito and P-38, there were very few successful day twin fighters. I'd say there might be some interesting development ahead.

And the P-38 was faster than the proposed Fw 187 might have been with the proposed DB 601's. The P-38 and some Mosquitoes were at least over 400 mph. The DB engined FW 187 would not have been by a good margin, if you look at power increase alone. Add some frontal area increase and it get slower. You could not substitute a 34% heavier engine with more power without encountering a bigger radiator and the atendant cooling drag increase, not to mention the heavier engine mounts and attendant strengthening of the airframe to support the heavier engines at the g-limit. My estimate with standa aedodynamic equations would have it in the 380 - 385 mph range with the DB 601's. Good, probably. But the best? Maybe.

Might have been a pretty good fighter, but better than one of the premier single seaters of all times, I strongly would like to see that before accepting it at face value.

Still, the concept has merit and I always wondered why the Germans didn't develop it, especially after the Bf 110 was shown to be a good aircraft but lacking when it came to day combat with single-engine fighters in the Battle of Britain. The DB Fw 187 might have been a good one, but I doubt the development would have been completely without some challenges. Maybe they could have adapted the Bf 110 engine cowling assemblies almost piece for piece, with the attendant strengthening.

The result might have given the real Mosquito and P-38 a run for their money. But some sort of design analysis would need to be forthcoming to accept the claims.

Given the political situation at the time, I think it more likely that the existing real line of aircraft might have been produced a bit sooner in greater numbers if they had to rely on just aircraft. The same could be said of the British and Americans.

This one is an interesting "what if," and DonL could be right. Of course, the Allies could come up with some new things, too. 

Lastly development might have gone along different lines than it really did, with completely new airframes and engines.

In that case, what would be flying NOW? Some interesting speculations DonL. Got any drawings of your proposed planes? Not that it is necessary, but cool planes are always welcome.


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## Civettone (Jun 2, 2013)

What exactly were Messerschmitt's performance projections for the DB 600 powered Fw 187? 560 kmh? 

I am not sure if it would be possible to install the DB 601 without further modifications. But the Bf 110 went from Jumo 210 to DB 605 ...
Kris


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## wiking85 (Jun 2, 2013)

GregP said:


> I see DonL is going to design a new twin from the Fw 187, with heavier engines, never built, and state that it would not be outclassed by anything, despite that fact that, except for the Mosquito and P-38, there were very few successful day twin fighters. I'd say there might be some interesting development ahead.
> 
> And the P-38 was faster than the proposed Fw 187 might have been with the proposed DB 601's. It was at least over 400 mph. The DB engined FW 187 would not have been by a good margin. You could not substitute a 34% heavier engine with more power without encountering a bigger radiator and the atendant cooling drag increase, not to mention the heavier engine mounts and attendant strengthening of the airframe to support the heavier engines at the g-limit. My estimate with standa aedodynamic equations would have it in the 380 - 385 mkph range with the DB 601's. Good, but the best? Maybe.
> 
> Might have been a pretty good fighter, but better than one of the premier single seaters of all times, I strongly would like to see that before accepting it at face value.


 
https://en.wikipedia.org/wiki/Super...performance_and_armament#Early_Merlin_engines
Well, the Mark II Spitfire was the model the Fw187 would have faced in the BoB. It had a top speed of just under 360mph and had less than half the internal fuel of the Fw187. Not only that, but it was slower in a dive or climb, thanks to the DB601's fuel injection system. Beyond that most fighters shot down in the BoB (~80%) didn't see the enemy coming, so much was based on who was superior in boom-and-zoom, rather than the Spitfire's favored turn-and-burn tactics. So the Fw187 would have a serious advantage over the Spitfire, so long as its not taken by surprise or let's itself get sucked into a turn-and-burn battle; considering that its very likely only the best pilots would be allowed for fly such an aircraft and the quality of German fighter pilots relative to the RAF ones during the BoB, then its more than likely that the extra speed, climb, dive, and range capabilities of the Fw187 over the Spitfire (not yet cannon-armed), would be pretty hard to overcome by the RAF fighter units, especially given that they were still using the Vick formation as of August 1940.


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## altsym (Jun 2, 2013)

Milosh said:


> The flight flight of the Me262V1 was on *18 April 1941*. BoB had been over for a few months.


Thanks for the correction


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## Aozora (Jun 2, 2013)

wiking85 said:


> https://en.wikipedia.org/wiki/Super...performance_and_armament#Early_Merlin_engines
> Well, the Mark II Spitfire was the model the Fw187 would have faced in the BoB. It had a top speed of just under 360mph and had less than half the internal fuel of the Fw187. Not only that, but it was slower in a dive or climb, thanks to the DB601's fuel injection system.



I would really like to see the figures that will convincingly show that the Fw-187 would have done all of these things, particularly the climbing and diving: I have Hermann and Petrick's book on the Fw 187 and all I see are lots of _projected_ performance figures for planned Fw 187 derivatives when fitted with various engine types, including the DB605. There is no mention _anywhere_ of the confirmed or projected diving speeds so I cannot see how such claims can be confirmed. 

Fw 187 V4 rate of climb = 12.1 m/sec = 2,381 ft/min, gross weight = 4,900 kg: projected Fw 187 with DB605 = 13 m/sec = 2,559 ft/min, gross weight = 8,200 kg.

There was only one Fw 187, the V5, tested with DB601s using evaporative cooling; the only performance figure quoted is 635 km/h (394 mph) "at low altitude", with the engines developing 1,350 hp - there is no indication whether this was with armament or at full loaded weight. It is doubtful whether the RLM would have continued with evaporative cooled DB601s because the system was far too vulnerable to battle damage, not to mention the nightmares of maintenance at a unit level, and supply issues involved in manufacturing and issuing yet another version of the DB601 when there were already problems involved in manufacturing and supplying the standard models. Another problem was that supplies of C3 96 Octane fuel were always problematic and unreliable





wiking85 said:


> Beyond that most fighters shot down in the BoB (~80%) didn't see the enemy coming, so much was based on who was superior in boom-and-zoom, rather than the Spitfire's favored turn-and-burn tactics. So the Fw187 would have a serious advantage over the Spitfire, so long as its not taken by surprise or let's itself get sucked into a turn-and-burn battle; considering that its very likely only the best pilots would be allowed for fly such an aircraft



All this means is that the Spitfire would be at a disadvantage if surprised by an Fw 187, which is meaningless really because any fighter caught by surprise is at a disadvantage. "considering that its very likely only the best pilots would be allowed for fly such an aircraft" evidence for this please - chances are had the Fw 187 been built in quantity it would have been issued to Geschwader, just like any other aircraft type, and not individual pilots or "elite" units.


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## bob44 (Jun 2, 2013)

davebender said:


> IMO Fw-187 would have been best fighter aircraft in the world during 1940 bar none. And it was production ready.
> 
> However the original question concerned getting a jet into combat during BoB.



Not necessarily during the BOB. But putting some serious effort into a jet fighter early in the war.

Also brings up a question. Did Germany have any intelligence on the Spitfire? Or did they just dismiss it. Thinking the 109 is better?


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## DonL (Jun 3, 2013)

> I would really like to see the figures that will convincingly show that the Fw-187 would have done all of these things, particularly the climbing and diving: I have Hermann and Petrick's book on the Fw 187 and all I see are lots of projected performance figures for planned Fw 187 derivatives when fitted with various engine types, including the DB605. There is no mention anywhere of the confirmed or projected diving speeds so I cannot see how such claims can be confirmed.
> 
> Fw 187 V4 rate of climb = 12.1 m/sec = 2,381 ft/min, gross weight = 4,900 kg: *projected Fw 187 with DB605 = 13 m/sec = 2,559 ft/min, gross weight = 8,200 kg.*
> *There was only one Fw 187, the V5, tested with DB601s using evaporative cooling; the only performance figure quoted is 635 km/h (394 mph) "at low altitude", with the engines developing 1,350 hp *- there is no indication whether this was with armament or at full loaded weight. It is doubtful whether the RLM would have continued with evaporative cooled DB601s because the system was far too vulnerable to battle damage, not to mention the nightmares of maintenance at a unit level, and supply issues involved in manufacturing and issuing yet another version of the DB601 when there were already problems involved in manufacturing and supplying the standard models. Another problem was that supplies of C3 96 Octane fuel were always problematic and unreliable.



If you have this book and has read it accurate (and the book is accurate translated) I can't understand your claims here, because they are simply wrong!

1. The climb rate you are claiming is with a 1000kg Bomb at external racks, without the 1000kg Bomb it was 18,0m/s; Page 135
2. The FW 187 V5 didn't receive DB 601 H engines, it was flying with the DB 601 V40 + V42 with 1100PS; Page 78 
3. The FW 187 V5 didn't flew with an evaporative cooling (Oberflächenverdampfungskühlung), it flew with a Dampfheißkühlung. This system is fundemental different to the He 100 evaporative cooling, where water was circulating through the wings. The system of the FW 187 was an experimental high pressure cooling with very smal *convential radiators* (no water at the wings)and every later developed engine from DB 605, Jumo 213 and DB 603 received a steam seperator for high pressure cooling. Page 73-78
4. Look at page 81/82 you can see the radiators under the engine.
5. Also there are several reports from pilots about the flight performance of the FW 187 at Rechlin (Page 37) and at Page 95 against a Me 110 with DB 601 engines at Denmark.



> I see DonL is going to design a new twin from the Fw 187, with heavier engines, never built, and state that it would not be outclassed by anything, despite that fact that, except for the Mosquito and P-38, there were very few successful day twin fighters. I'd say there might be some interesting development ahead.



I haven't anything designed Mr. GregP the FW 187 *was built with DB 601 engines ( FW 187 V5) and the FW 187 was constructed from the scratch to the DB engines, because this was the advertisement of the RLM*
The FW 187 V5 flew from 1939 till 1942 and FW was able to receive countless of flight data's and the FW 187 V5 had not a single problem with the g-limit



> And the P-38 was faster than the proposed Fw 187 might have been with the proposed DB 601's. The P-38 and some Mosquitoes were at least over 400 mph. *The DB engined FW 187 would not have been by a good margin, if you look at power increase alone. Add some frontal area increase and it get slower. You could not substitute a 34% heavier engine with more power without encountering a bigger radiator and the atendant cooling drag increase, not to mention the heavier engine mounts and attendant strengthening of the airframe to support the heavier engines at the g-limit. *My estimate with standa aedodynamic equations would have it in the 380 - 385 mph range with the DB 601's. Good, probably. But the best? Maybe.



Mr. Greg P you has realy no clue about what you are writing!

1. The FW 187 was designed to support the heavier engines from the beginning, no modifications are necessary.
2, The change from Jumo 210 engies to DB 601 engines had reduced the drag of the *ME 110* significant through much better radiators and resulted in a speed increase of 85km/h with *bigger* engines.. The FW 187 A0 flew the same radiotors and engines as the Bf 110 B with Jumo 210 engines.
So what do you think would be the speed increase of the FW 187 with the change to the DB 601 engines, if the Bf 110 could increase it's speed about 85 km/h and the FW 187 had the better aerodynamic?

To show you the aerodynamic category of the FW 187 from hard clocked facts/datas, we can compare the FW 187 V1 and the FW 187 V4.


FW 187 V1 single seater

loaded weight: 3.850 kg	
Wingspan:	30,00 m²	
Wing loading: 128,33 kg/m²	
engines: Jumo 210D 2x680 PS	
Top speedt	501 kmh at 3.000 m	
climb:	17,5 m/s

FW 187 V4 two seater

loaded weight: 4.900 kg
Wingspan:	30,20 m²	
Wing loading:165,56 kg/m²	
engines: Jumo 210G 2x730 PS	
Top speedt	545 kmh at 4.600 m	
climb:	12,5 m/s

The main difference were the engines, because the 210G had a two speed supercharger, fuel injection and was the first Jumo 210 with boost effect.
As you can see the FW 187 V4 was 1000kg heavier then the Fw 187 V1, but could increase it's top speed through the better supercharger and boost effect from 500 to 540 km/h.

This is the official specification from FW engineers of the FW 187 with DB 605 engines: 

Official specification:

Fw 187 - destroyer/nightfighter from 1942

Wingspan: 15,3
Wing area: 30 qm
Length: 12,45
crew: 2 (200 kg)
empty weight: 5600 kg
take off weight: 8200 kg (with 1 x 1000 kg Bombe)
engine: DB 605
estimated range with internal fuel: 1200 km
estimated range with internal fuel and 900 Liter drop tank: 2100km

Performance:
682 kmh at 7.000m altitude (at 6.620 kg), 658 kmh at 7.000 m with 1000 kg bomb capacity at external racks
547 kmh (at 6.620 kg)at SL
climb rate at SL: 13,0 m/s at 8.200kg (with 1000kg bomg capacity) , 18,0 m/s bei 6.620 kg
climb: 6000m in 5,7 Minuten (with 6.620 kg),
armament:
4 x 151 / 20 with 250 bullets each - fixed to the front
2 x 131 with 450 bullets each - as "Schräge Musik"
1 x MG 81 with 750 bullets - flexible to the back
in summaryt: weapons 392 kg; munition 306 kg)
loading:
maximal 2.000 kg
1 x 1000 kg + 2 x 500 kg or
1 x 1000 kg + 4 x 250 kg or
10 x 50 kg bzw. 10 x AB 23 / 24

With what arguments do you claim that this datas are wrong and a Moussie and a P38 would be faster?
With what arguments do you claim that FW engineers, educated piston engine aircraft engineers are wrong with their official specification, with countless datas of testflights of the FW 187 A0 and FW 187 V5 with DB 601 engines. 
From engineers that presented official specifications for the FW 190 A0- A9, FW 190-D9-13, Ta 152 H, FW 200 etc and all this official specification were *reached in real-life* from production a/c's.

Where is your argument that engineers who worked about 5 years with this a/c can't do a proper official specification but you know it better?
Are you a piston engine aircraft engineer?


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## wiking85 (Jun 3, 2013)

Aozora said:


> I would really like to see the figures that will convincingly show that the Fw-187 would have done all of these things, particularly the climbing and diving: I have Hermann and Petrick's book on the Fw 187 and all I see are lots of _projected_ performance figures for planned Fw 187 derivatives when fitted with various engine types, including the DB605. There is no mention _anywhere_ of the confirmed or projected diving speeds so I cannot see how such claims can be confirmed.
> 
> Fw 187 V4 rate of climb = 12.1 m/sec = 2,381 ft/min, gross weight = 4,900 kg: projected Fw 187 with DB605 = 13 m/sec = 2,559 ft/min, gross weight = 8,200 kg.
> 
> There was only one Fw 187, the V5, tested with DB601s using evaporative cooling; the only performance figure quoted is 635 km/h (394 mph) "at low altitude", with the engines developing 1,350 hp - there is no indication whether this was with armament or at full loaded weight. It is doubtful whether the RLM would have continued with evaporative cooled DB601s because the system was far too vulnerable to battle damage, not to mention the nightmares of maintenance at a unit level, and supply issues involved in manufacturing and issuing yet another version of the DB601 when there were already problems involved in manufacturing and supplying the standard models. Another problem was that supplies of C3 96 Octane fuel were always problematic and unreliable


Unfortunately its a hypothetical aircraft, so there is no such thing as convincing evidence if you're demanding a working example's data as proof.
Confirmation is impossible, but given the performance of the various prototypes it seems that the clean lines of the aircraft, even without the surface evaporative cooling, gave it its much higher speed in level flight than would be expected from such an aircraft. Also the issue of its superior dive speed has more to do with the DB engines than just its aerodynamics, as the early Merlins that powered the Mark II Spitfires had performance issues when switching into a dive, which was noted by Stephen Bungay in his book on the BoB 'Most Dangerous Enemy'. Regardless of whatever you think about the potential impact or performance of the aircraft, it would have been superior in performance to the Bf110.




Aozora said:


> All this means is that the Spitfire would be at a disadvantage if surprised by an Fw 187, which is meaningless really because any fighter caught by surprise is at a disadvantage. "considering that its very likely only the best pilots would be allowed for fly such an aircraft" evidence for this please - chances are had the Fw 187 been built in quantity it would have been issued to Geschwader, just like any other aircraft type, and not individual pilots or "elite" units.


I may have been supposing to much by making that comment, as I'm assuming that this aircraft would replace the Bf110, which was supposedly only for elite units, which would mean that as its replacement in production, it would take the place as the 'elite' aircraft.


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## wiking85 (Jun 3, 2013)

Sorry, double post.


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## Marcel (Jun 3, 2013)

DonL said:


> The Bf 109F-4 was better or equal to the Spitfire V
> The FW 190A outclassed the Spitfire V at 1942
> A Fw 187 with two DB 601A1 would have outclassed a Spitfire MK II and V at Speed, dive, range and arnament. With two DB 601F (1350PS), it would had outclassed the Spitfire IX from speed, dive, range and arnament.


I read a book about Bader in which describes clearly that the Bf109F was definitely not superior to the Mk.V. The FW190A on the other hand clearly was.


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## GregP (Jun 3, 2013)

Wiking85, 

Purely as a query, what would fuel injection have to do with superior climb? Might have a short effect in a bunt dive ay first, but in a climb, the carburetor has no disadvantage. The superior skill of the Luftwaffe pilots in the BOB didn't seem to prevent them from losing it, even with "superior" aircraft, so I'm not sure where that came from. If they had better planes and better pilots, what was the cause for the loss? In my mind, the issues were leadership, target selection, and short-duration fighters coupled with no real plan for prosecuting or finishing the battle. By leadership, I don't mean leadership at the unit level, which was good, I mean leadership at the highest levels of the battle plan.


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## OldSkeptic (Jun 3, 2013)

Perfectly correct Greg. FI had no affect on climbing and had a negative affect on supercharger effiency, due to the lack of charge cooling.

It was also more complex, harder to make, maintain and more costly.

In the pre electronic fuel injection days there was no real gain and, especially with turbo/super charged engines several downsides.
The correct way, used in Merlin 100 series engines, to do fuel injection was at the supercharger inlet.

There is an article in the Flight Glabal archives rolls-royce merlin | 1941 | 0562 | Flight Archive

That compares a Merlin X (first 2 speed Merlin, without Hooker's improvements) and a Jumo 211D. Came to the conclusion that it wasn't worth it.


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## OldSkeptic (Jun 3, 2013)

Marcel said:


> I read a book about Bader in which describes clearly that the Bf109F was definitely not superior to the Mk.V. The FW190A on the other hand clearly was.



The 109F and the Mk V were very close in overall performance, as were the Spit 1 and 109E. One had some advantages over the other and vice versa, anyone that claims otherwise I think are kidding themselves.


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## DonL (Jun 3, 2013)

OldSkeptic said:


> Perfectly correct Greg. FI had no affect on climbing and had a negative affect on supercharger effiency, due to the lack of charge cooling.
> 
> It was also more complex, harder to make, maintain and more costly.
> 
> ...



Then you can please explain to me why both, the Jumo 210G (fuel injection) compare to the Jumo 210 D and the DB 601A (fuel injection) compare the DB 600, had both more power output (horsepower) and both fuel injection engines a better high altitude performance through a better supercharger effency and both fuel injection engines create more boost. How is this possible?


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## Tante Ju (Jun 3, 2013)

Marcel said:


> I read a book about Bader in which describes clearly that the Bf109F was definitely not superior to the Mk.V. The FW190A on the other hand clearly was.


 
That would depend on the type. The 601N powered F-1/2 was slightly faster, especially since the Mark V. had serious production quality issues and was not faster in practice than the Mark I or II; the 601N on the other hand some development troubles and may or may have not developed full power in service.

The F-4 is a different class altogether, even the initial 1.3 ata rating is much better than Mark V, the 1942 version with 1.42 ata could do about 670 kph, that's much faster than the Mark V and about as fast as the 109G or Mark IX.


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## Jabberwocky (Jun 3, 2013)

Tante Ju said:


> That would depend on the type. The 601N powered F-1/2 was slightly faster, especially since the Mark V. had serious production quality issues and was not faster in practice than the Mark I or II; the 601N on the other hand some development troubles and may or may have not developed full power in service.
> 
> The F-4 is a different class altogether, even the initial 1.3 ata rating is much better than Mark V, the 1942 version with 1.42 ata could do about 670 kph, that's much faster than the Mark V and about as fast as the 109G or Mark IX.



Which Mk V's factories/production runs had "serious production quality issues"?

If you're referring to some Mk Vs underperforming (typically by 15-20 mph) in RAF tests, I suggest you look at the age and condition of the tested aircraft before blaming production quality.


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## OldSkeptic (Jun 3, 2013)

DonL said:


> Then you can please explain to me why both, the Jumo 210G (fuel injection) compare to the Jumo 210 D and the DB 601A (fuel injection) compare the DB 600, had both more power output (horsepower) and both fuel injection engines a better high altitude performance through a better supercharger effency and both fuel injection engines create more boost. How is this possible?



The DB-601 had a different supercharger.

They were later engines, boost went up over time (moderately for German engines, plus different valve timing and revs limits) in the endless struggle for more power. 

The Jumo 211D had fuel injection (as per the article, it has pictures of it all disassembled).

The RLM apparently mandated fuel injection to be used, yet another of its (many) daft decisions.

Re the Jumo: "A major upgrade was started in 1940 in order to better compete with the 601, following in its footsteps with a pressurized cooling system. The resulting 211E proved to be able to run at much higher power settings without overheating, so it was quickly followed by the 211F which included a strengthened crankshaft and a more efficient supercharger. Running at 2,600 RPM the 211F delivered 1,340 PS and the 211J (a 211F with intercooler) delivered 1,420 PS. Further improvements to this basic line led to the 1,450 PS 211N and 1,500 PS 211P in 1943, they were equivalent to the 211F/J but with slight boost increases and running at up to 2,700 rpm. Continued development of the 211 line evolved into the 213." Wikipedia (not fact checked)by myself).

Interesting the almost universal use of fuel injection these days in cars, but people forget why that was. Pollution controls basically. Mandatory limits made the price difference shrink (yes you could trick up a carby to do it but it became as expensive as fuel injection). Computer controlled electronic injection, as it was introduced, made significant differences in performance and fuel economy. Even more so as turbo charged engines have become more the norm.

Amazing how that 27ltr Merlin managed to develop as much (or often more) power as its 33, 36, 42, etc litre German opponents. And with a carby too ... someone knew what they were doing....


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## OldSkeptic (Jun 3, 2013)

Tante Ju said:


> That would depend on the type. The 601N powered F-1/2 was slightly faster, especially since the Mark V. had serious production quality issues and was not faster in practice than the Mark I or II; the 601N on the other hand some development troubles and may or may have not developed full power in service.
> 
> The F-4 is a different class altogether, even the initial 1.3 ata rating is much better than Mark V, the 1942 version with 1.42 ata could do about 670 kph, that's much faster than the Mark V and about as fast as the 109G or Mark IX.



Your numbers are wrong, but you have also made a good point.

The Spit V went through increasing boost levels which matched, or exceeded, the 109 at the various times.

But quality is a serious issue that the Germans and the US markedly exceeded the British in just about every area of production. 
By and large the Britsh were the worst (excepting Rolls Royce), the Germans next and the US was (overall) the best in aircraft.

The German's weakness was far too complex designs, which despite their better quality meant they were more expensive and time consuming to build. The Tiger tank being the prime example.
The US, when it got its act together (which took some time), built good designs with good quality (except tanks of course).

You look at a Spit vs a Mustang or a 109, the better build quality is obvious (against the Spit that is).

What that meant in operational issues was important, now the allowable limit of a Spit was 3% (and everyone was tested). That meant that the average (official) top speed of 404mph for a LF MK IX (Merlin 66) could vary between 392mph and 416mph. Naturally, experienced pilots (and especially the higher ranked) got the good ones.

Maintenance was the other issue, out of the factory a plane could do Xmph, after a few months of combat it got slower and slower. Panels being opened and closed, dents, engine aging and so on.
You have your brand new P-51B that makes 440 mph (+- something), after 6 months of operations you would struggle to make 420 (or less).

Naturally, again, the top people got the best maintenance.

Translated: if you were down the pecking order you flew in a heap of rubbish, crap to begin with got even worse over time.

German _Expertin_, got the best, British and US experienced people and higher commanders (unless they were technically unskilled and unpopular and the rest of the squadron conspired to give them something poor) got the best. 

If you were a newbie and unpopular .....


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## Aozora (Jun 3, 2013)

DonL said:


> If you have this book and has read it accurate (and the book is accurate translated) I can't understand your claims here, because they are simply wrong!
> 
> 1. The climb rate you are claiming is with a 1000kg Bomb at external racks, without the 1000kg Bomb it was 18,0m/s; Page 135









True, but then again these _estimated or projected_ figures are confused anyway - the weight quoted without 1000 kg bomb is 6,620 lbs, but this is light because there is a weights table for the "improved Fw 197C" earlier in the book which shows the following: 

equipped weight = 5,658 kg (minus bomb racks) = 5618 kg: 

to this must be added Crew = 200 kg; fuel= 960 kg; oil= 70 kg; ammunition= 306 kg so additional load without bomb = 1,536 kg = 

*Gross Weight without bomb = 7,154 kg* or 534 kg _heavier_ than the 6,620 kg quoted for maximum climb speed of 18 m/sec = 3,453 ft/min. (3,453 ft/min is not really that spectacular anyway) 






It can thus be taken that the rate of climb at a realistic weight, with crew, fuel, ammo, is somewhat slower than 18 m/sec. Plus there is no indication of the weights for the maximum speed quoted - chances are it is also measured at a minimal weight of 6,620 kg, or without some 530 kg of fuel and/or ammunition. 



DonL said:


> 2. The FW 187 V5 didn't receive DB 601 H engines, it was flying with the DB 601 V40 + V42 with 1100PS; Page 78
> 3. The FW 187 V5 didn't flew with an evaporative cooling (Oberflächenverdampfungskühlung), it flew with a Dampfheißkühlung. This system is fundemental different to the He 100 evaporative cooling, where water was circulating through the wings. The system of the FW 187 was an experimental high pressure cooling with very smal *convential radiators* (no water at the wings)and every later developed engine from DB 605, Jumo 213 and DB 603 received a steam seperator for high pressure cooling. Page 73-78
> 4. Look at page 81/82 you can see the radiators under the engine.



So? My comments still stand -an Fw 187 with Dampfheißkühlung would have introduced yet another DB601 variant into an already stretched supply chain; I doubt if this would have been acceptable to the RLM which was trying to limit the engine variants being used. Nor is there any indication as to whether or not the system would have been worthwhile under combat conditions.

Also note the commentary above the first table:


> The He 219 was selected over the Fw 187, at least for the nightfighter role. Why was this? No official reason has yet been discovered.



For one thing the Fw 187 had a very narrow fuselage; chances are it would not have been able to carry the typical radar equipment able to be carried by the He 219 or Bf 110 or Ju 88 without a large amount of modification. As it is the weight table shows that radio equipment - minus radar, Naxos etc - to be fitted weighed 141 kg: FuG 220 SN2 alone weighed 70 kg and any antenna would have also added to weight and drag.



DonL said:


> To show you the aerodynamic category of the FW 187 from hard clocked facts/datas, we can compare the FW 187 V1 and the FW 187 V4.
> 
> 
> FW 187 V1 single seater
> ...



Do these loaded weights include essential items like armour, fuel, ammunition - note, for example, that no armour had been fitted to any of the Fw 187 prototypes. Once again we have the weights and specifications of prototypes, not operational aircraft.


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## Aozora (Jun 3, 2013)

DonL said:


> Then you can please explain to me why both, the Jumo 210G (fuel injection) compare to the Jumo 210 D and the DB 601A (fuel injection) compare the DB 600, had both more power output (horsepower) and both fuel injection engines a better high altitude performance through a better supercharger effency and both fuel injection engines create more boost. How is this possible?


 
You've answered your own question - it was because of _improved supercharger efficiency_ that engine performance increased, no doubt because new superchargers were developed hand in hand with fuel injection to compensate for the power losses due to the reduced thermal efficiency of early mechanical fuel injection systems. Why add new superchargers to engines which were already considered to be obsolescent?


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## Shortround6 (Jun 3, 2013)

DonL said:


> Then you can please explain to me why both, the Jumo 210G (fuel injection) compare to the Jumo 210 D and the DB 601A (fuel injection) compare the DB 600, had both more power output (horsepower) and both fuel injection engines a better high altitude performance through a better supercharger effency and both fuel injection engines create more boost. How is this possible?



Without knowing more details it is hard to say what was causing what. 

The Fuel injection _eliminates_ mixture distribution problems that just about ALL carburetor engines suffered from ( cylinders did not all get the same amount of fuel and air and even the same fuel/air ratio).
It allows a slightly higher compression to be used ( engine is not limited to the _weakest_ cylinder like a carburetor engine) but I don't know if the injected Jumo 210 models and the DB 601 took advantage of that. 
It allows for better fuel economy as (once again) all cylinders are getting the same amount of fuel and some are not running "rich" in order to ensure that the leanest cylinder is getting enough fuel. 

None of these have anything to do with supercharger efficiency and some of the early German superchargers used some pretty terrible impeller designs. DO we know if some of the engines in question also changed impellers or other supercharger parts? 
Did they use exactly the same gear ratios on the same superchargers?
Perhaps the improved fuel distribution allowed for a higher gear ratio to be used? 

Still has little to do with supercharger _efficiency_ even if a higher boost is used. 

Most early superchargers (1939 or earlier), no matter how bad, could deliver more boost than the engines could use with 87 octane fuel. But boost is not really efficiency. 

There is simply too much going on (or too many unkowns) to say that the fuel injection affected supercharge performance. Yes the injected engines made more power than the carburetor engines.


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## cimmex (Jun 3, 2013)

Sorry Aozora, in my eyes your statement is nonsense. In 1979 I bought a new car a brand-new Golf GTI with K-tronic fuel injection and 110 hp. The motor was basically the same as in the standard Golf
with carburettor and 75 hp. I would say this is an improvement and as a unit a new engine.
cimmex


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## Tante Ju (Jun 3, 2013)

Theoretically the advantage of carburetor was that the fuel injected into the carburetor cooled down and thus compressed the air, easing the engine's workload driving the supercharger. How much that gain amounted is the real question - German studies of water injection showed about 4% gain from injecting water alone (without increasing boost), which would amount to about 40-50 HP. That's not much and I would place a bet that the gain from using a carbburator is even less, especially in practical conditions, since carburetor also needs a lot of gimmicks installed to function safely - ice guards and so on, which decrease efficiency. In addition, that gain in power is probably further diminished/cancelled by the fact that fuel consumption is increased further (and as SR6 noted, DFI allows for higher compression, increasing fuel effiency even more), thus more fuel/weight needs to be carried by the airplane. Throttle response if probably worse, and there's always a danger of backfire as opposed to DFI engines.

The Flight article is interesting, but IMHO its more of a PR article from RR. Beggars cant be choosers, RR had no D.F.I. technology available, hell they even had problems making carburetors working properly... neither did they have any working engine in the 30 liter class - though they were developing the Griffon. It wasn't really a choice for them but a necessity, and make their arguments sound a very cheap. RR was an extremely conservative company and not very open to innovation. Still, they did one hell of a job with the Merlin, a conventional engine in all aspects, despite its limits with displacement. Given the constraints with a war going on and no time to develop a new 30-litre class engine (a path everyone choose in the end, but took steps sooner than RR), and no time to adop DFI, they did the right thing and sticking to what was already working was justifiable on the grounds of practicability, but not on engineering grounds. They made the best out of what was available, despite the handicaps of smaller displacement and having to do with carburetors. But that doesn't mean IMHO that their arguments against D.F.I. were valid at all (and apparently even at the time major figures in engine development strongly disagreed with them).


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## rinkol (Jun 3, 2013)

I would attribute the success of the Merlin to the following:

- development of efficient superchargers, particularly the two stage supercharger with intercooling;
- the use of wet cylinder liners;
- better fuel and materials;
- intensive development.

Fuel injection did provide significant advantages, aside from being suitable for operation under zero or negative g conditions, it provided more uniform fuel distribution and avoided problems with backfires. The later versions of the R-3350 received fuel injection to address the former issue.


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## Kryten (Jun 3, 2013)

Carbs not only cool the inlet charge, they had superior emulsification of the fuel into the inlet charge, they are also density/pressure sensitive, as altitude increases the air density obviously drops and a carb "self compensates" as the fuel pickup is directly relative to the volume, density and pressure of the air flowing through it! old mechanical injection had to have a compensating device which is only as good as its mechanical map allows!

Also throttle response is better with a carb, it took years and high tech electronics to get fuel injection to surpass carbs in this regard, the fuel injection used in the 40's was extremely crude, only in neg G did it have a clearcut advantage over a carb!


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## Tante Ju (Jun 3, 2013)

Kryten said:


> Also throttle response is better with a carb, it took years and high tech electronics to get fuel injection to surpass carbs in this regard, the fuel injection used in the 40's was extremely crude, only in neg G did it have a clearcut advantage over a carb!


 
This may be true for car engines, but evidently not so for aircraft engines. The following is from a British trial report of a DB engined 109:

_Throttle. – The throttle arrangements were described by one pilot as " marvellously simple, there just being one lever with no gate or over-ride to worry about ". It may be mentioned here that, while the pilots were not greatly impressed with the Me.109 as an aircraft, the D.B.601 direct injection engine came in for very favourable comment. *The response to throttle opening is particularly good, it is apparently impossible to choke the engine, and there is no tendency to splutter and stop when the aircraft is subjected to a negative g by suddenly pushing the stick forward.*_

Its seems logical that the basis of comparison (response, choking, neg g comment) were contemporary carb RR engines.


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## altsym (Jun 3, 2013)

No way, no how, no when, a carb is better then direct port injection. Even in 1940. On a carb engine with a supercharger, that air/fuel mix will be hot, turbulent, the fuel will tend to separate from the air mix, and the fuel will be leaner in the cylinders further from the carb. One won't get those problems with direct port injection. 30 year drag racer talking here.

For fun, look up the specs for the MECHANICAL fuel injection specs for the 1957 Chevrolet 283 The 1964 327 Chevrolet. Crude, rude, but got much better horsepower economy then there carbureted counterparts.


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## Aozora (Jun 3, 2013)

Tante Ju said:


> The Flight article is interesting, but IMHO its more of a PR article from RR....RR was an extremely conservative company and not very open to innovation. Still, they did one hell of a job with the Merlin, a conventional engine in all aspects, despite its limits with displacement. Given the constraints with a war going on and no time to develop a new 30-litre class engine (a path everyone choose in the end, but took steps sooner than RR), and no time to adop DFI, they did the right thing and sticking to what was already working was justifiable on the grounds of practicability, but not on engineering grounds. They made the best out of what was available, despite the handicaps of smaller displacement and having to do with carburetors. But that doesn't mean IMHO that their arguments against D.F.I. were valid at all (and apparently even at the time major figures in engine development strongly disagreed with them).



That "extreme conservatism" is why R-R were world leaders in helping to devise and adopt new high-strength high-temperature alloys, such as Hiduminium for their engines and that's why they adopted two-stage two-speed superchargers and intercoolers. And, of course, that conservatism meant that they didn't bypass direct injection in favour of adopting the Bendix-Stromberg direct injection system as soon as was practicable, because it was a better system than both carburettors or direct injection into the cylinders. (The Bendix Stromberg system was described by Flight in 1941: )

Carburettor, Injection or?
Carburettor, Injection or?

and here

Bendix-Stromberg pressure injection
1941 | 2102 | Flight Archive
1941 | 2103 | Flight Archive
1941 | 2104 | Flight Archive

To claim that Rolls-Royce didn't go with direct injection because of their supposed "extreme conservatism" is the usual simplification and myth making of the ignorant, similar to the claims about what a horribly complex aircraft the Spitfire was to build. Luftwaffephile always like to describe the problems with fuel starvation


> choking, neg g comment)


 during the Battle of Britain but don't seem to recognise that relatively small engineering changes eliminated the problem, which was then bypassed completely when the Bendix Stromberg direct injection carburettor was adopted.


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## Shortround6 (Jun 3, 2013)

Britain didn't have the support infrastructure (read sub-contractors) to make direct fuel injection units in the numbers needed. 

On the Merlin XX engine the intake charge was cooled by 25 degrees C by the evaporation of fuel in the supercharger. Other models may show slightly different numbers. 

In the early years of car racing fuel injection (1940s and 50s) could give more power but it tended to be less flexible. Poorer response at part throttle or near idle, not a consideration for racers but helped prevent normal non racing cars from going to it. 

How much time does an aircraft engine spend at full or near full throttle compared to cruising? 

They were different and each did have pluses and minuses. I am not sure which was better OVERALL at the TIME. What cars use 30-60 years later has next to NO bearing as most cars are not supercharged, the systems, both carburetor and fuel injection are not the same, manufacturing base (ability/cost to make) is not the same, engine performance goals are not the same (what pollution control on a 1940s aircraft engine????)


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## altsym (Jun 3, 2013)

How many times does a aircraft change its speed in a non-combat/normal flight? I'm sure throttle response wasn't that big of a deal.
That Rochester Fuel Injection on those 283s 327s were archaic as compared to say the DB605 DPI. No pollution control on those Chevys,
And part throttle response was there. NOT saying WW2 DPI systems were perfect, but certainly better the carbs. I don't know enough about
the Merlin Bendix-Stromberg unit other then it gives continuous injection of fuel into the entry of the supercharger. I don't think I ever read of an account of pilots complaining about a lack of 'get up and go' with the DB series engines.

The only 'Pro' I seen with carbs are its simplicity. I've never seen temp drops on 25^c on a roots or centrifical supercharger without intercoolers. 
Even the BEST carbureted engines today the mix settings etc are tempermental, nevermind if you use it on a supercharger. And that's with todays
tech.

So how does a single carb solve for the lean out conditions on the outmost cylinders? Manifold design helps, varying the ignition timing per cylinder also helps. That's at the cost of the more inboard cylinders running way to rich. With DPI, problem solved.

Anyways great conversation


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## Shortround6 (Jun 3, 2013)

Are you using suck through or blow though carb set ups?

Did you measure the the temp with and without fuel flowing though the supercharger but the supercharger supplying air at the desired pressures/volumes. 

A Merlin XX at full power is going though over 2 gallons a minute of fuel. Granted it is also going through a LOT of air. 

Big difference between cars and aircraft is that the Merlin XX was supplying a Manifold pressure of 9lbs (about 48in absolute) at 18,000ft or so and compressing the ambient air just over 3 times. This would be like a car at sea level having a supercharger supplying 30lbs of boost or 90in absolute. There was a lot more heat in the intake charge than most car engines ever see. Just supplying sea level pressure air at 20,000ft with a supercharger that was 65% efficient would see a temperature rise of about 175 degrees F above the ambiant air. Now compress it another 50% or so?


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## GregP (Jun 3, 2013)

I can't find any reference that says the Fw 187 V5 was ever equipped with other than Jumo 210 engines. Maybe the paper follow-on planes were calculated with DB 601, DB 603 or DB 605 engines, but can anyone post a reference that shows an actualy flying Fw 187 was so equipped? I can find only the Fw 187 V6 that had DB's and it had the carbureted DB 600A's, not DB 601's. It also had a surface evaporative cooling system that gave a lot of trouble.

I believe the three 2-seat Fw 187's were used as factory test beds, but have never found out the details of the tests or the changes made to them before they were taken out of service, other than that in the winter of 42/43 they were used to study the potential use of the Fw 187 as a night fighter. That does not imply engine changes.

The subject hasn't exactly been completely documented in the books I have read, so maybe there are some data out there showing such. The planes LOOK good and seemed to perform at a good level, but seem to have been killed both by politics and by lack of defensive armament in being selected for the Destroyer role.


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## davebender (Jun 3, 2013)

Jumo 210 engine ended production during 1938.

If Fw-187 enters mass production it will be during 1939 or 1940.

Common sense suggests Fw-187 was never intended for Jumo 210 engine. If Fw-187 prototypes were forced to use an engine that was out of production it was RLMs way of telling Focke Wulf their aircraft program was dead on arrival. He-112 program received similar treatment.


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## DonL (Jun 3, 2013)

GregP said:


> I can't find any reference that says the Fw 187 V5 was ever equipped with other than Jumo 210 engines. Maybe the paper follow-on planes were calculated with DB 601, DB 603 or DB 605 engines, but can anyone post a reference that shows an actualy flying Fw 187 was so equipped? I can find only the Fw 187 V6 that had DB's and it had the carbureted DB 600A's, not DB 601's. It also had a surface evaporative cooling system that gave a lot of trouble.
> 
> I believe the three 2-seat Fw 187's were used as factory test beds, but have never found out the details of the tests or the changes made to them before they were taken out of service, other than that in the winter of 42/43 they were used to study the potential use of the Fw 187 as a night fighter. That does not imply engine changes.
> 
> The subject hasn't exactly been completely documented in the books I have read, so maybe there are some data out there showing such. The planes LOOK good and seemed to perform at a good level, but seem to have been killed both by politics and by lack of defensive armament in being selected for the Destroyer role.



The complete history of this a/c is in this book:
Focke-Wulf FW 187: An Illustrated History: Amazon.de: Dietmar Harmann: Englische Bücher

The book is basing on original documents from Focker Wulf.
Please read my Post 37 and the PM I have send you.
At this book are official original specifications from Focker Wulf engineers with layout drawings for the FW 187 V4/A0 and the FW 187 as nightfighter/destroyer (1942) and as high altitude single seater fighter (1942). Also there are many photos at this book, also from the FW 187 V5 with DB 601 engines, that showed the small radiators of the FW 187 V5, which was *not* flying with a surface evaporative cooling system.

Here are several members at this forum with this book and I hope they will confirm my informations.


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## altsym (Jun 3, 2013)

@ shortround6; 

Used both centrifugal (blow through) and roots (draw through) and I can say without a doubt draw through heats the air/fuel mix like crazy.
This is determined by measuring exhaust gas temperatures, fuel flow, a/f ratio. Using the same engine, and changing to a blow through 
blower, I can run 3-4 degrees more timing at the same boost pressure, and measuring exhaust gas temps , etc., overall, much better.


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## GregP (Jun 3, 2013)

Thanks for the reference, DonL!

Hey DonL ... is that title available in English to your knowledge?


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## bobbysocks (Jun 3, 2013)

i am sorry DonL...i cant buy the 109G being meat on the table. it's abilities were respected by us airmen and i know of accounts where the LW pilots (in G-10s) gave the airmen one hell of a fight....and took down its share of allied planes. i dont know any who thought it was a piece of junk or were relieved when they found that it was what they were dogfighting with. i will agree that it was an airframe that had little room left to expand on...especially trying to fit the duel role of fighter and bomber interceptor.....and that another SE fighter airframe should have been in the works as early as 41/42. but a lot of that was dependant on the german industry, economy, and politics. the 109 gave a damn good account of itself up to the end of the war. i always wondered how the models would have progressed if the LW had been able to keep it purely as a fighter and had something else to engage the bombers....


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## davebender (Jun 3, 2013)

Germany had two promising Me-109 replacements during 1942.
.....Fw-190C.
.....Me-309.
Both aircraft required the DB603 engine which RLM cancelled during 1937 to 1940 and then funded at only a low level.

This isn't an airframe issue. It's an engine issue. If RLM wants to replace Me-109 with a larger / heavier / better armed / longer range fighter aircraft they need the larger DB603 engine.


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## Shortround6 (Jun 3, 2013)

altsym said:


> @ shortround6;
> 
> Used both centrifugal (blow through) and roots (draw through) .



They gave up on Roots superchargers for aircraft in the 1920s because of the inefficiency (heating of the intake charge). The NACA did do some testing with them and the reports should be on the NASA server. 

NASA - Search Results


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## altsym (Jun 3, 2013)

Links are dead. But I suspect even with a centrifugal supercharger used as a 'draw through' type ( carb on the inlet side of the supercharger), the A/F mix temps would be somewhat high (as compared to Direct Cylinder Injection), unless an intercooler was used. But even that's dangerous, IF fuel collects in the intercooler and the engine backfires, its all over rover.

Correct me if I'm wrong, but didn't those Bendix-Stromberg throttle bodies use some means to heat the fuel to prevent icing?


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## wuzak (Jun 3, 2013)

altsym said:


> Links are dead. But I suspect even with a centrifugal supercharger used as a 'draw through' type ( carb on the inlet side of the supercharger), the A/F mix temps would be somewhat high (as compared to Direct Cylinder Injection), unless an intercooler was used. But even that's dangerous, IF fuel collects in the intercooler and the engine backfires, its all over rover.
> 
> Correct me if I'm wrong, but didn't those Bendix-Stromberg throttle bodies use some means to heat the fuel to prevent icing?



Yes, the air fuel mixture would be high for the draw through system (like that used in the Merlin).

But, it won't be as high as the air in a system where no fuel is added (ie direct injection, like DB 6).

It also highlights the different philosophies of the two engine manufacturers - Daimler-Benz opted for capacity, high compression and low boost (relatively). Rolls-Royce followed the path of the R engine - high boost, low compression ratio.

For the high boost route the fuel into the eye of the supercharger was invaluable in lowering induction temperatures.


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## Aozora (Jun 3, 2013)

GregP said:


> Thanks for the reference, DonL!
> 
> Hey DonL ... is that title available in English to your knowledge?


 
See my post  #47 which has excerpts from the book, including part of the weight table for an improved Fw 187 using DB 605s or BMW 801s. Schiffer Publishing Ltd (8 Sep 2004), English, ISBN 978-0764318719. Unfortunately Amazon list it as "Temporarily out of stock" Focke-Wulf Fw 187: Amazon.co.uk: Deitmar Hermann, Peter Petrick: Books

The British weren't the only ones to have reservations about direct fuel injection, because the United States Navy had also examined the concept:















The usual claim seems to be that Rolls-Royce and other British manufacturers were somehow "backward" or ignorant in not adopting DFI and this, in turn, shows how advanced the Germans were:



Tante Ju said:


> The Flight article is interesting, but IMHO its more of a PR article from RR._ Beggars cant be choosers, RR had no D.F.I. technology available_, hell they even had problems making carburetors working properly... neither did they have any working engine in the 30 liter class - though they were developing the Griffon. It wasn't really a choice for them but a necessity, and make their arguments sound a very cheap. RR was an extremely conservative company and not very open to innovation.Still, they did one hell of a job with the Merlin, a conventional engine in all aspects, despite its limits with displacement. Given the constraints with a war going on and no time to develop a new 30-litre class engine (a path everyone choose in the end, but took steps sooner than RR), and no time to adop DFI, they did the right thing and sticking to what was already working _was justifiable on the grounds of practicability, but not on engineering grounds_. They made the best out of what was available, despite the handicaps of smaller displacement and having to do with carburetors.



The problem with such a pet theory is that it doesn't allow for the fact that the technology of both DFI and aero engines capable of developing 1,000 hp and well over was still new, and that there were perfectly legitimate doubts about the efficacy of using DFI in such high powered, supercharged engines. That Daimler Benz - via Bosch - and Junkers developed reliable DFI systems was a great achievement, but to use that in an attempt to damm the Merlin (with some faint praise) and other engines which did not adopt DFI is just ill-informed nonsense. 



altsym said:


> Correct me if I'm wrong, but didn't those Bendix-Stromberg throttle bodies use some means to heat the fuel to prevent icing?



No because, as the Flight article here explains:



> The Stromberg possesses the following qualities:
> (I) Freedom from icing-up because no fuel whatsoever passes the throttles.


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## Shortround6 (Jun 3, 2013)

altsym said:


> Links are dead. But I suspect even with a centrifugal supercharger used as a 'draw through' type ( carb on the inlet side of the supercharger), the A/F mix temps would be somewhat high (as compared to Direct Cylinder Injection), unless an intercooler was used. But even that's dangerous, IF fuel collects in the intercooler and the engine backfires, its all over rover.
> 
> Correct me if I'm wrong, but didn't those Bendix-Stromberg throttle bodies use some means to heat the fuel to prevent icing?



Some links are , some are not. They have changed the front pages since the last time I visited. 

Only one aircraft engine in WW II used an intercooler (or after cooler ?) with a single stage supercharger, a certain model of the Jumo 211. The other engines with inter-coolers (or after coolers) had two stage superchargers. The supercharger heats the air, the fuel evaporating in the supercharger can lower the temperature, The direct injection system cannot. The Germans injected the fuel directly into the cylinder between the spark plugs, not into intake ports or above the intake valves. 

I shouldn't think that heating the fuel will help the Bendix-Stromberg much. The Fuel was being injected into the eye of the supercharger, a number of inches away from the throttle body, in some models or from the base of the throttle body or adapter. In any case several inches below (after) the throttle plates.


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## altsym (Jun 3, 2013)

Shortround6 said:


> The supercharger heats the air, the fuel evaporating in the supercharger can lower the temperature, The direct injection system cannot.


Isn't that was this was for (along with the 'Ram' effect) to cool the intake charge? 






Thanks for the info/links for the Bendix-Stromberg throttle body..


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## wuzak (Jun 3, 2013)

altsym said:


> Isn't that was this was for (along with the 'Ram' effect) to cool the intake charge?
> 
> 
> 
> ...



No. That was for intake air and ram effect. It does nothing to cool the air after the supercharger. Of course having cooler air to start with helps, but Rolls-Royce engines also had such intakes.


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## Aozora (Jun 3, 2013)

wuzak said:


> No. That was for intake air and ram effect. It does nothing to cool the air after the supercharger. Of course having cooler air to start with helps, but Rolls-Royce engines also had such intakes.



For interest here's an article which explains the working of carburettor air intakes  AEHS Article - carby air scoops. pdf

When Stanley Hooker was recruited by Rolls-Royce one of his first jobs was to redesign the carburettor air intake for the Merlin after he had discovered that it was badly designed. In 1941 Hooker wrote a report for R-R analysing the performance of the Merlin in particular, and which had a great deal of bearing on later developments: an analysis of this report can be found  here: AEHS article. pdf.


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## Shortround6 (Jun 3, 2013)

I fail to understand how that cools the intake charge.

On a car you have a choice, hot under hood air or cool outside air. 

On an airplane you have the same choice, sort of, the provision of thousands of cubic feet of air per minute needs a bit more thought than just trying to suck it from inside the cowl. A forward facing airscoop does provide "ram" air, it also WILL heat the air slightly, If the air reaching the carburetor (or engine inlet as opposed to airframe inlet) is at higher air pressure than the ambient air then the air was compressed in the intake duct and if it was compressed it was heated (or it's temperature raised).

We are now getting into technical hair splitting. A couple of degrees more or less is not a big deal, 20-30 degrees C is. 

RR (Hooker) said the Fuel evaporation was worth 25 degrees C, they had the test instruments, the test stands and test houses ( they could supply air at controlled temperature, pressure and humidity to the engine intake) they had flight tests, both their own and from users like Hawker. What reason did they have to lie? To cover up their NOT adopting direct fuel injection? 

The figure was given in this booklet.

Performance of a Supercharged Aero Engine by Stanley Hooker. It is available from Amazon. 

By the way, the booklet has a good chapter on exhaust thrust.


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## altsym (Jun 3, 2013)

Well 2 degrees _could_ be the difference between max power and catastrophic detonation. Lets say for example, if a supercharged engine is pushing 10 psi of boost at sea level (ambient pressure of 14.7 psi, ambient temperature of 24°C @ sea level, the temperature of the air after the supercharger will be 71.4 °C. At 22°C air after the supercharger is 64°C. Now if the detonation point was 69°C air after the supercharger, that 2°C just made the difference. All well in good on just the engine/supercharger, right? Now you have the 50%/50% water-methanol to throw into the equation.


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## wuzak (Jun 4, 2013)

altsym said:


> Well 2 degrees _could_ be the difference between max power and catastrophic detonation. Lets say for example, if a supercharged engine is pushing 10 psi of boost at sea level (ambient pressure of 14.7 psi, ambient temperature of 24°C @ sea level, the temperature of the air after the supercharger will be 71.4 °C. At 22°C air after the supercharger is 64°C. Now if the detonation point was 69°C air after the supercharger, that 2°C just made the difference. All well in good on just the engine/supercharger, right? Now you have the 50%/50% water-methanol to throw into the equation.



Where/how did you calculate those temperatures, using what assumptions.

2°C difference at intake does not make 7°C at the discharge.


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## wuzak (Jun 4, 2013)

Double post


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## wuzak (Jun 4, 2013)

altsym said:


> Well 2 degrees _could_ be the difference between max power and catastrophic detonation. Lets say for example, if a supercharged engine is pushing 10 psi of boost at sea level (ambient pressure of 14.7 psi, ambient temperature of 24°C @ sea level, the temperature of the air after the supercharger will be 71.4 °C. At 22°C air after the supercharger is 64°C. Now if the detonation point was 69°C air after the supercharger, that 2°C just made the difference. All well in good on just the engine/supercharger, right? Now you have the 50%/50% water-methanol to throw into the equation.



I get 71.5° with inlet of 24°C and 69.2 with inlet of 22°C.

Note that ADI/MW50 is a consumable.


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## OldSkeptic (Jun 4, 2013)

wuzak said:


> I get 71.5° with inlet of 24°C and 69.2 with inlet of 22°C.
> 
> Note that ADI/MW50 is a consumable.



Well said. Those that advocate ADI and NO2 forget that it increases the weight of the plane and takes up volume (always very limited in a fighter).
And of course doesn't last long. Plus you have the logistics issues, maintenance, et al.

RR went for simplicity as far as possible, which was part of their genius, as per the old saying "any fool can make things complex, it takes a genius to keep things simple".

Yes there were NO2 boosted Merlins, used in night fighter Mossies (big enough to take the volume) and water injection was tested during the war and used post war, nearly always just for take off (the Methanol part is an anti-freeze). Heck they even tested liquid oxygen (which was far better than NO2).

But the production decisions RR made were a compromise between sheer raw power, logistics, manufacturing, maintenance, etc.

Hooker's great contribution was his equations, which meant they could focus in the particular areas that mattered. So the Merlin 100 series lifted FTH by 4,000ft with the same power, just by its greater pressure efficiency (comparing similar high/lo variations of course), that's a big gain. Compare the Merlin X vs the XX and you see even greater gains because of the higher supercharger efficiency. (The X was the 2 speed prototype without the Hooker supercharger changes).

But the greatest compliment paid by the Germans was by (in their own complicated way) copying the idea, at least by BMW.
C3 injection. They added fuel into .... the supercharger inlet, cooling the intake and allowing higher boost .. still had fuel injection to every cylinder


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## Tante Ju (Jun 4, 2013)

OldSkeptic said:


> Well said. Those that advocate ADI and NO2 forget that it increases the weight of the plane and takes up volume (always very limited in a fighter). And of course doesn't last long. Plus you have the logistics issues, maintenance, et al.



I wonder why aircraft like the Hellcat, Thunderbolt, Mustang H etc. bothered at all with ADI when they had all those wonderful, state of the art carburators... 



> But the greatest compliment paid by the Germans was by (in their own complicated way) copying the idea, at least by BMW.
> C3 injection. They added fuel into .... the supercharger inlet, cooling the intake and allowing higher boost .. still had fuel injection to every cylinder


 
"_Copying_" what exactly..? That an engine needs fuel feed...? The carburetor? Float carburetor was developed by _Herren _Wilhelm Maybach and Gottlieb Daimler in 1885 (with notable Italian and Hungarian contribution to carburetor inventions)... or perhaps was it the Otto motor principle that they copied from mighty RR?  Until the mid-1930s all large German aero piston engines were carburetor fed (see for example DB 600, the forerunner of the DFI DB 601), they were well aware of the difference between carburetors 

The simple answer as to why RR developed its engines (again, quite ingeniously considering their limits) the way it did was that it did not have either the time to develop a completely new engine in wartime in the 30-liter class (the "alternative" to further developing the existing Merlin was waiting for the Griffon until 1943/44..), nor the reliable domestic suppliers of DFI systems: they simply did not have access to Bosch AG products - AFAIK (and could be well wrong) the current DFI systems are essentially the same as the ones developed by Bosch right before WW2.

If the _only _thing you can mass produce is a 27 liter engine with a carburetor, then its going to be a 27 liter engine with a carburetor plus loads of explanations why this is really the superior way (while frantically developing your own 35 liter engine, the thing _others _have already done 5-10 years before). If you are stuck with a relatively small engine and trying to compete with big engines in output, you will have to rely on ever extreme amounts of supercharging. In that case you will probably inclined to keep the carburetor a bit longer, as even the minor, ultimately insufficient charge cooling bonus it provides can help to stay competitive. As I said, beggars can't be choosers, though they would probably like to argue that becoming a career beggar was a consciously made choice.


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## wuzak (Jun 4, 2013)

Tante Ju said:


> The simple answer as to why RR developed its engines (again, quite ingeniously considering their limits) the way it did was that it did not have either the time to develop a completely new engine in wartime in the 30-liter class (the "alternative" to further developing the existing Merlin was waiting for the Griffon until 1943/44..), nor the reliable domestic suppliers of DFI systems: they simply did not have access to Bosch AG products - AFAIK (and could be well wrong) the current DFI systems are essentially the same as the ones developed by Bosch right before WW2.



What's the fascination with a capacity class? It is the power class that matters - and there the Merlin was a match for, or better than, the DB 601/605.

It was a concious decision on Rolls-Royce's part to use low compression ratios and high boost to achieve the power. It was Daimler-Benz's approach to use larger capacity and lower boost to achieve the power.

The Griffon was started in 1938/39 and was in service by 1942. It was an all new design. Not sure why you say about waiting for the Griffon until 1943/44. As far as I can tell the main reason why the Griffon didn't come on sooner was that production of existing types and engines took precedent.




Tante Ju said:


> If the _only _thing you can mass produce is a 27 liter engine with a carburetor, then its going to be a 27 liter engine with a carburetor plus loads of explanations why this is really the superior way (while frantically developing your own 35 liter engine, the thing _others _have already done 5-10 years before). If you are stuck with a relatively small engine and trying to compete with big engines in output, you will have to rely on ever extreme amounts of supercharging. In that case you will probably inclined to keep the carburetor a bit longer, as even the minor, ultimately insufficient charge cooling bonus it provides can help to stay competitive. As I said, beggars can't be choosers, though they would probably like to argue that becoming a career beggar was a consciously made choice.



I don't think there was anything "frantic" about the development of the Griffon.

The Griffon wasn't, originally, to replace the Merlin. It was a response to a request from the FAA for a larger capacity, more powerful engine to help with their heavier (than land based) carrier types.


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## wuzak (Jun 4, 2013)

Tante Ju said:


> I wonder why aircraft like the Hellcat, Thunderbolt, Mustang H etc. bothered at all with ADI when they had all those wonderful, state of the art carburators...



The Packard Merlin in the P-51H was the only type of Rolls-Royce engine, or derivative, that had ADI during the war. The reason was to screw even more boost out - from +25psi to +30psi.

The radials used them because they needed more control of temperatures, and had less resistance to detonation (hence they generally used lower boost).

Allison V-1710s with ADI tended to not use intercooling.


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## Aozora (Jun 4, 2013)

Tante Ju said:


> I wonder why aircraft like the Hellcat, Thunderbolt, Mustang H etc. bothered at all with ADI when they had all those wonderful, state of the art carburators...



Tssk tsssk, such ignorance... ; the "carburetors" concerned were the Bendix or Chandler throttle body injection units, which were state of the art, and had been adopted by the Americans well before Germany adopted DFI.


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## Tante Ju (Jun 4, 2013)

Style like this



Aozora said:


> To claim that Rolls-Royce didn't go with direct injection because of their supposed "extreme conservatism" is *the usual simplification and myth making of the ignorant*





Aozora said:


> *Luftwaffephile always like to describe *the problems with fuel starvation during the Battle of Britain but don't seem to recognise that relatively small engineering changes eliminated the problem, which was then bypassed completely when the Bendix Stromberg direct injection carburettor was adopted.





Aozora said:


> The problem with such a pet theory is that it doesn't allow for the fact that ...





Aozora said:


> That Daimler Benz - via Bosch - and Junkers developed reliable DFI systems was a great achievement, but to use that in an attempt to damm the Merlin (with some faint praise) and other engines which did not adopt DFI * is just ill-informed nonsense.*





Aozora said:


> Tssk tsssk, such ignorance...



will only getting you (a) ignored (b) being short lived on this board.

You just ticked (a) BTW.


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## Shortround6 (Jun 4, 2013)

Rolls had run a Merlin on a test stand at 1600hp for 15 hours in 1938, and gotten more power out of for it shorter periods. They KNEW the basic engine would stand up to higher than 1000-1200hp with minor tweaks. This _allowed_ them to put the Griffon on the back burner for a while. If the Merlin had proved to need major work to make 1500hp or more in 1938 then they probably would have worked on the Griffon more. 

Again, this is testing the basic structure of the engine, getting the engine to MAKE 1500-1800hp at altitude is another story. 

Fuel injection would NOT have gotten as much power out of the big radials as water-injection did. As already mentioned, they were temperature limited. When running at full power they consumed large amounts of fuel that had nothing to do with burning it for power, they were using it not only to cool the intake charge (like Rolls) but to cool the engine from the inside. When fitted with water injection the carburetor had _de-enrichment circuit_ and they used 30-40 gallons LESS fuel per hour while making 250-300hp MORE horsepower. Fuel flows in the charts are given on a per hour basis even when the engine was limited to 5 min. at that power setting. 

Fuel injection can do some very good things but lets not claim it could do things that it actually could NOT do. 

I am in agreement with Wuzak about the constant harping on the displacement of the Merlin. Power per liter matters to _engine designers_. AIR FRAME designers could care a _flying *****_ about it. The Single stage Merlins and the Allison and the DB 601 and the Jumo 211 in 1939/40/41 were ALL fairly close to each other in BOTH power and *WEIGHT* which is what interests the air frame designer. HOW they got that power at that weight is up to the engine designer. Small displacement and high rpm or large displacement and low rpm. NOBODY's boost was all that high in 1937-39 when the engines were designed and brought into service.


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## DonL (Jun 4, 2013)

@ wuzak



wuzak said:


> Yes, the air fuel mixture would be high for the draw through system (like that used in the Merlin).
> 
> But, it won't be as high as the air in a system where no fuel is added (ie direct injection, like DB 6).
> 
> ...





> What's the fascination with a capacity class? It is the power class that matters - and there the Merlin was a match for, or better than, the DB 601/605.
> 
> It was a concious decision on Rolls-Royce's part to use low compression ratios and high boost to achieve the power. It was Daimler-Benz's approach to use larger capacity and lower boost to achieve the power.





> The Packard Merlin in the P-51H was the only type of Rolls-Royce engine, or derivative, that had ADI during the war. The reason was to screw even more boost out - from +25psi to +30psi.



I have some questions:

1. Could it be, that the different design philosophies had to do with the quality of fuel and the knock resistance of the expected fuel?
From all I could read about german engine development, the engineers were well aware, that they were stuck basically on B4 fuel, also that the possibility to use and *produce* high grade B4 fuel wasn't given until 1936, as the IG Faben get the patent of lead tetraethy from Standard oil. 
The germans had never the chance of the whole WWII to produce high grad fuel with/out of isooctane, because they don't have isooctane and don't know the development.
To my understanding this was one of the main reason they developed from the beginning to more capacity engines, because for higher boost (ata), you are in need for high grade fuel.

2. Also there was (Jumo 211, Jumo 213; compare to DB 601, DB 605, DB 603) a different design philosophy between the german engine factories Junkers and DB.
DB built it's engine from dry weight very light. The DB 601/DB 605 is at the same weight class of the Allison 1710 and RR Merlin with 33/35,9 Liter compare to 28 Liter engines, the DB 603 44 Liter at the same class as the RR Griffon and the Jumo 213 35/36 Liter engines.
At first sight to me, DB bought this "light weight" with relative low RPM's. After the development of the Jumo 213 out of the Jumo 211 with high pressure water cooling, Junkers was able drive the Jumo 213 with 500 rpm more then the Jumo 211. DB was not able to manage a much higher RPM at the DB 605 (100 RPM higher then the DB 601), although the DB 605 was converted also to a high pressure water cooling and sleeve bearings instead of roller bearings.
The DB 605 was next to the DB 603 compare to RR (Merlin, Griffon), Allison (V1710; Junkers (Jumo 213), the inline engine, that was driven with the lowest RPM.

I couldn't fathom this to the ground, but there must be different design philosophies.


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## wuzak (Jun 4, 2013)

DonL said:


> 1. Could it be, that the different design philosophies had to do with the quality of fuel and the knock resistance of the expected fuel?
> From all I could read about german engine development, the engineers were well aware, that they were stuck basically on B4 fuel, also that the possibility to use and *produce* high grade B4 fuel wasn't given until 1936, as the IG Faben get the patent of lead tetraethy from Standard oil.
> The germans had never the chance of the whole WWII to produce high grad fuel with/out of isooctane, because they don't have isooctane and don't know the development.
> To my understanding this was one of the main reason they developed from the beginning to more capacity engines, because for higher boost (ata), you are in need for high grade fuel.



I think that is a distinct possibility.

Rolls-Royce did follow that path when they went racing with the R, requiring special fuels to be developed.

When the Merlin was being developed the fuel they had on offer wasn't that great. But there was better fuel being developed in the US. So that may have allowed them to believe that even better fuels would be available in the future.

By the same token, the requirements from the engine manufacturers also drove fuel development. 

And when better fuels were available Rolls-Royce were able to take full advantage.

Tetra-ethyl lead was used to give British and American fuels the better knock resistance. Not sure if Germany also had that, but alcohol is also an octane booster.




DonL said:


> 2. Also there was (Jumo 211, Jumo 213; compare to DB 601, DB 605, DB 603) a different design philosophy between the german engine factories Junkers and DB.
> DB built it's engine from dry weight very light. The DB 601/DB 605 is at the same weight class of the Allison 1710 and RR Merlin with 33/35,9 Liter compare to 28 Liter engines, the DB 603 44 Liter at the same class as the RR Griffon and the Jumo 213 35/36 Liter engines.
> At first sight to me, DB bought this "light weight" with relative low RPM's. After the development of the Jumo 213 out of the Jumo 211 with high pressure water cooling, Junkers was able drive the Jumo 213 with 500 rpm more then the Jumo 211. DB was not able to manage a much higher RPM at the DB 605 (100 RPM higher then the DB 601), although the DB 605 was converted also to a high pressure water cooling and sleeve bearings instead of roller bearings.
> The DB 605 was next to the DB 603 compare to RR (Merlin, Griffon), Allison (V1710; Junkers (Jumo 213), the inline engine, that was driven with the lowest RPM.
> ...



You're right about the Junkers having a different philosophy to Daimler-Benz. Something I never really considered, and always seems to be glossed over, the discussion usually returning to DB 6 vs Merlin/Griffon.

Did Junkers have 2 or 3 speed superchargers, rather than the variable speed superchargers of the DB series?


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## DonL (Jun 4, 2013)

> Did Junkers have 2 or 3 speed superchargers, rather than the variable speed superchargers of the DB series?


Yes Junkers worked with 2 speed superchargers and *not* variable speed superchargers like DB, till the Jumo 213E, which had the *first two stage* 3 speed supercharger of any german engine in production.


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## Shortround6 (Jun 4, 2013)

In 1935-36 everybody had 87 octane fuel, they knew 100 octane was coming (Howard Hughes set the world speed record in 1935 using 100 octane) but they did not WHEN 100 octane was coming as a PRACTICAL fuel ( Howard's fuel cost 4.00 a gallon, many times normal aviation fuel). The basic decisions as to engine size, rpm and such were made at this time. 
This is one reason for the British Rolls Royce Vulture, While they may KNOW the Merlin could STAND UP to 1600-1800hp they could not get that power from a service engine using service fuel. 
A DB 601 was about 22% bigger than the Merlin in displacement but the early ones ran at about 20% slower so the actual air through the engine was within a few % of each other at similar boost levels. and the early engine weighed very close to each other and put out similar amounts of power. 
Once production lines are established it becomes a question of how much power can be squeezed out of the existing design and here is where the British had an advantage in fuel. The British went through at least FOUR different fuel specifications/capabilities. 
WHile they knew 100 octane fuel was coming NOBODY had any idea IF or WHEN such things as 100/130 or 100/150 would ever show up. It was almost science fiction in 1937-38.


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## DonL (Jun 4, 2013)

@ SR6

I don't disagree with your summary, but fuel was always a serious issue to Germany, and as I said, they did get the patent of lead tetraethy from Standard oil not until 1936.
So to my opinion perhaps german engine designer were a little more conservative/careful and choose capacity against boost.

What do you expect from a "what if" german 28 Liter engine, that would be stuck to B4 or later perhaps C3 with Junkers philosophy and 3200 rpm?
I don't think this "what if" engine would be able to get past 1300 PS (take of power) under the given circumstances.

I also think that MW 50 and GM1 were only developed, because of a compensation of their "low" grade B4 fuel the entire war.
The criticism of Oldskeptip is to me absurd, because he is assuming equality of arms, which was never given at the fuel issue.


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## altsym (Jun 4, 2013)

wuzak said:


> Where/how did you calculate those temperatures, using what assumptions.


T2/T1 = (p2/p1) y-1/y

Where: 
T1= ambient air temperature
T2= temperature after the compressor
p1= ambient atmospheric pressure (absolute)
p2= pressure after the compressor (absolute)
Y = Ratio of specific heat capacities = Cp/Cv= 1.4 for air
Cp= Specific heat at constant pressure
Cv= Specific heat at constant volume


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## Aozora (Jun 4, 2013)

Shortround6 said:


> In 1935-36 everybody had 87 octane fuel, they knew 100 octane was coming (Howard Hughes set the world speed record in 1935 using 100 octane) but they did not WHEN 100 octane was coming as a PRACTICAL fuel ( Howard's fuel cost 4.00 a gallon, many times normal aviation fuel). The basic decisions as to engine size, rpm and such were made at this time.
> This is one reason for the British Rolls Royce Vulture, While they may KNOW the Merlin could STAND UP to 1600-1800hp they could not get that power from a service engine using service fuel.
> A DB 601 was about 22% bigger than the Merlin in displacement but the early ones ran at about 20% slower so the actual air through the engine was within a few % of each other at similar boost levels. and the early engine weighed very close to each other and put out similar amounts of power.
> Once production lines are established it becomes a question of how much power can be squeezed out of the existing design and here is where the British had an advantage in fuel. The British went through at least FOUR different fuel specifications/capabilities.
> WHile they knew 100 octane fuel was coming NOBODY had any idea IF or WHEN such things as 100/130 or 100/150 would ever show up. It was almost science fiction in 1937-38.



Not quite; in 1937-1938 100 Octane fuel was being trialled on at least three RAF squadrons:






In September 1938 100 Octane was approved for use in Hurricanes and Spitfires:






Rolls-Royce were exhibiting 100 octane fueled Merlin Xs and quoting figures for Merlin IIs in December 1938:






while, at about the same time, the first deliveries of non-trail quantities to Fighter Command stations was underway:


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## Shortround6 (Jun 4, 2013)

In the engines designed in 1934-37 it was more a question of of capacity (displacement) vs rpm. Max boost was still pretty low in most engine. 

The Kestrel used in the Bf 109 and Ju 87 prototypes used a max of 3.5lbs boost (1.24 ata?). Granted it was an in service engine and not a prototype. 

R-R had Built the the 35 liter Condor from 1918 to 1926 or so ( and a diesel version in 1932) plus the Buzzard of 36.7 liters which they developed into the "R" racing engines. The Buzzard only weighed 1140lbs. 

I don't know why R-R dropped to 27 liters for the Merlin but they certainly had experience and the capability to build larger engines. But Rolls had only been making aircraft engines for less than 20 years, the idea that the Merlin would still be in first line service 10-15 years in the future would probably have shocked the designers of the time. The Merlin being R-Rs 6th commercial (non racing) engine in under 20 years. 

I think you are right in that a 27-28 liter engine with 87 octane fuel would not have made it past 1300 PS no matter who made it.

MW-50 does help with the lower octane fuel ( and helps with the cooling too). GM-1 is sort of split. it provides extra power pretty much ONLY at high altitudes and is sort of a replacement for two stage superchargers. Of course two stage superchargers rather depend on high performance fuel as even with inter coolers the intake charge can be hundreds of degrees F due to compressing the air 5-6 times at altitude so even if the total boost is held to only 6-12lbs that level of boost at 25,000-30,000ft requires a different fuel than the same level of boost at 15-20,000ft. 
If the Germans had more access to high performance fuel earlier and could be assured of continued large scale access they might have take a different path.

They might have pushed too hard for fuel economy given their fuel situation which hurts peak power production. The Allison used higher compression than the Merlin up until the post war engines, it gave better cruise performance (power per unit of fuel burned) but limited the amount of boost that could be used at any given time in comparison to the Merlin. The Post war engines used in teh P-82 dropped the compression to the same as the Merlin and used more boost than war time engines. 

raising the compression ratio raises the peak pressure in the cylinders (requiring heavier construction) faster than raising the boost to get the SAME power.


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## Shortround6 (Jun 4, 2013)

Aozora said:


> Not quite; in 1937-1938 100 Octane fuel was being trialled on at least three RAF squadrons:
> 
> 
> In September 1938 100 Octane was approved for use in Hurricanes and Spitfires:
> ...



There was a big difference between 1935-36 and 1938. And in 1938 the British didn't understand ( nobody really did) what the actual differences were between British 100 octane fuel and American 100 octane fuel and how it would affect engine performance. as for 100/130 fuel?? the performance number scale that the 130 part comes from didn't exist until late 1040 or early 1941. You can't have OVER 100 octane fuel. The octane rating scale is based on comparing the test fuel to known reference fuels which were blends of iso-ocatane and heptane. 87 octane fuel has to ACT like a blend of of 87% iso-octane and 13% heptane even if it contained little, if any, of those two compounds. Once you hit 100% iso-octane you had no way to measure performance above that level until a new rating scale was established. 
They knew they could get better performance that 100% iso-octane but they didn't know how to measure it or how to specify it. Or test batches of gas BEFORE putting it the engine or aircraft. The _idea_ that you could have a fuel that would allow 30-50% MORE performance than 100% iso-octane in 1938 was close to science fiction. People could and did predict it was coming but nobody could say when, or how. 
British 1940 "100 octane" was NOT 100/130 fuel. It was usually 100/115 to 100/120 depending on batch and/or refinery once the test procedures were instituted. Of course once you CAN TEST the result it is a lot easier to vary small batches to come up with the results you want.


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## tomo pauk (Jun 4, 2013)

Seem the discussion is now in less bickering and more in data, informations and analysis - thanks to the contributors.


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## Balljoint (Jun 4, 2013)

It may be useful to this discussion to review the several mechanisms to allow fuel to burn rather than detonate in an engine. The bad actor is actually the O2 molecule. When subjected to temperature and or pressure, the O2 forms highly reactive free radicals which come in two progressive reactivities. The more reactive, given the more extreme conditions that cause its formation, causes cascading reactions, i.e. detonation. Thus limiting fuel charge pressure and temperature is the prime cure for detonation.

Tetraethyl lead is just a carrier for the lead in that it breaks down under the high temperature/pressure freeing the lead. The free lead is highly reactive and soaks up the O2 free radicals to prevent detonation.

Yet another distinct approach to high octane rating is to form bigger, cyclic molecules that are more resistant to rapid combustion. This is accomplished through cracking and reforming petroleum feed stocks to end up with ultrahigh octane fuel. Reforming was probably the key to production of large quantities of high octane fuels. Just a thought, but since Germany was starting from coal to make fuel –and munitions- , reformation should have been within their technical capabilities though, as with other needs, developing the capacity may have been problematical.


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## tomo pauk (Jun 4, 2013)

One forum member mentioned earlier that a license-built Hispano 12Y engine (in the UK) would be the good candidate for the Westland Whirlwind. Interestingly enough, the Germans have had under control, from early 1939 on, a factory that was making 12Ycrs engines under license - Avia of Czechoslovakia. Since the 12Y was far lighter than the DB-601 or Jumo 211, and only some 50 kilos heavier than the Jumo 210, why not install these engines on the Fw-187? The power jumps from 680 PS at 3700m to 860 PS at 4000 m; the take off power from 690 to 835 PS.


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## Aozora (Jun 4, 2013)

Shortround6 said:


> In the engines designed in 1934-37 it was more a question of of capacity (displacement) vs rpm. Max boost was still pretty low in most engine.
> 
> The Kestrel used in the Bf 109 and Ju 87 prototypes used a max of 3.5lbs boost (1.24 ata?). Granted it was an in service engine and not a prototype.
> 
> ...


 
Design of the Merlin started in 1932 (original concepts envisaged an inverted vee as one possible layout) and there was the possibility that the 37 litre R series would be adapted to become the next big engine; as such 27 litres was a good "halfway house" between that and the the 21 litre Kestrel (later the Peregrine). 

This was literal in that all R-R needed to do to go from 21 (Kestrel Bore: 5 in or 127 mm; Stroke: 5.5 in or 140 mm = 1,295.88 in³ (21.24 L)) to 27 litres was to increase the bore and stroke of each cylinder by roughly half an inch ie; Merlin: Bore: 5.4 in (137 mm) Stroke: 6.0 in (152 mm) 1,647 cu in (27 L): ditto to go up to 37 l Griffon Bore: 6 in (152.5 mm) Stroke: 6.6 in (167.6 mm) = 2,240 in3 (36.7 L). With their experience of the Rs Rolls-Royce knew they could get at least 1,000 hp out of a 27 l engine, with the added bonus that it would be reasonably compact for the power generated. 

As it was Rolls-Royce decided to design a new 37 l engine to take advantage of the refinements made in the Merlin cf the R series and, in turn, added further refinements resulting in the Griffon.

With the Jumo 210 Junkers started their 21 series with a similar engine to the Kestrel; the Jumo 210 was Bore: 124 mm (4.88 in) Stroke: 136 mm (5.35 in) Displacement: 19.7 l (1,202 in³), but with the 211 the dimensions went up by roughly an inch to Bore: 150 mm (5.91 in)Stroke: 165 mm (6.5 in) = 34.99 l (2,135.2 in³)


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## GregP (Jun 6, 2013)

Personally I like the Fw 187. But in the political atmosphere of the time, I don't think it would ever be adopted. The cirticisms leveled at it were lack of defensive aramament in the Destroyer role, not big enough for a radar fit in the fuselage, etc.

So despite being what would SEEM like a good candidate for a twin engine fighter, the people making the production desisions just didn't seem to want it.

However, the 12Y engine might have been a good idea and might have made a decent jump in performance while not using up the preferred DB engines. Not a bad choice, Tomo.


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## tomo pauk (Jun 6, 2013)

Of course, I've posted about the 12Y because it could've added numbers to the German engines produced, not because it was some wunder engine in 1939/40. It might be interesting to contemplate the He-100 and/or He-112 with 12Y, again from production viewpoint.


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## Shortround6 (Jun 6, 2013)

He-100 is a dead duck. The cowl was actually the engine mount. To change engines requires redesigning the plane from the firewall forward if not the firewall also, The Upper part of the cowl being sort of a double wall box beam (?) that the engine hung from. 
Great for access to an inverted V-12. Throw away and start over for an upright V-12. 
Now sort out the rest of the He-100s 'problems'.

He-112 is a maybe. But what do you have when you are done?


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## tomo pauk (Jun 7, 2013)

Re-engining the He-100 for a different type of in-line should not be harder that re-engining the in-line-engined fighter into a radial-engined one, or vice versa. Maybe install the whole power egg from the Avia 135, ditching the retractable raditor.

With He-112/12Y I have the fighter that can decently perform (the historic He-112 was making 510 km/h with Jumo-210s), and my allies can actually buy it, without waiting for Bf-109.


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## tomo pauk (Jun 7, 2013)

double post


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## Shortround6 (Jun 7, 2013)

tomo pauk said:


> Re-engining the He-100 for a different type of in-line should not be harder that re-engining the in-line-engined fighter into a radial-engined one,or vice versa.



On something like a P-36 to P-40 the engine mounts/bearers go to about the same attachment points _at_ the firewall/bulkhead/frame and the loads are transferred to the structure ( longerons, truss framework, whatever). The fuselage _covering/outer skin_ bears NO structural loads and is merely an aerodynamic covering for the engine ( and router of air for various needs).







The He 100 used something closer to this;











The outer covering is used (access hatches/doors aside) AS the engine mount. a more involved engineering problem. 

It is possible (most anything is possible) but is it practical. Main stress attachments have to shift from the top/upper sides to the bottom/lower sides of the fuselage at the firewall/bulkhead. 



tomo pauk said:


> Maybe install the whole power egg from the Avia 135, ditching the retractable raditor.








What "power egg"??

Just because a plane groups the radiator and oil cooler near the engine does not mean that the whole package (including cowl) comes off with just a few bolts/connections. 

The retractable radiator on the HE 100 was sort of an auxiliary cooler. The bulk of the cooling was done by the wing surfaces, and the turtle deck/vertical fin/horizontal stabilizer surfaces for the oil cooling system. 

I am not certain how much of the coolant was allowed to turn to steam in the He 100 system, if any. But the cooling requirements of the Hispano engine might be different than the DB engines used in the He 100.


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## DerAdlerIstGelandet (Jun 7, 2013)

The same usual people (both Luftwaffephiles snd Alliedofreaks - yeah you are just as bad) seem to be falling into the same old routine of snide remarks, insults and thread detracting comments. If I see one more post like thise, the offender can take it elseware. They won't be welcome here.

You all know who you are...


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## nuuumannn (Jun 7, 2013)

> The He 100 used something closer to this



The Ki-61, which the pictures in Shortround's post show, was re-engined with a radial to become the Ki-100, but as SR stated, the whole forward section of the aircraft would need redesigning. It was certainly possible, but not as simple as unbolting one engine and fitting another.


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## tomo pauk (Jun 7, 2013)

Shortround6 said:


> On something like a P-36 to P-40 the engine mounts/bearers go to about the same attachment points _at_ the firewall/bulkhead/frame and the loads are transferred to the structure ( longerons, truss framework, whatever). The fuselage _covering/outer skin_ bears NO structural loads and is merely an aerodynamic covering for the engine ( and router of air for various needs).
> ...
> 
> The He 100 used something closer to this;
> ...



Thanks for the feedback with pics, most interesting 
I'd just reiterate that other people were doing many planes' modifications, modifying the He-100 to use the engine not in the great demand for the LW might have pushed Heinkel's engineers to attempt mounting the 12Y on the He-100




> ...
> What "power egg"??
> 
> Just because a plane groups the radiator and oil cooler near the engine does not mean that the whole package (including cowl) comes off with just a few bolts/connections.



Okay, I stand corrected re. 'power egg' terminology. 



> The retractable radiator on the HE 100 was sort of an auxiliary cooler. The bulk of the cooling was done by the wing surfaces, and the turtle deck/vertical fin/horizontal stabilizer surfaces for the oil cooling system.
> I am not certain how much of the coolant was allowed to turn to steam in the He 100 system, if any. But the cooling requirements of the Hispano engine might be different than the DB engines used in the He 100.



The 12Y was making maybe 80 % of power the DB-601A was making, the cooling requirements should be smaller.


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## cimmex (Jun 7, 2013)

Engine swap is not as easy as you think. Even a similar engine like the Ash 82 instead a BMW801 caused a lot of problems at the Flugwerk FW190A-8N and it took years after meiermotors presented a satisfying solution.
cimmex
Focke Wulf Fw190 Baureihe A


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## Shortround6 (Jun 7, 2013)

Thank you for the link although I got a bit lost.

Found these pictures of the Hispano engine though;

Hispano-Suiza 12 Y


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## cimmex (Jun 7, 2013)

I have realized also that the first link is not working but the other two should work.
cimmex


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