Is the Spitfire Really Superior to the FW-190 ... continued

[DerAdlerIstGelandet]

I did not know that MW-50 was corrosive to the engines. Can you tell me more about it.

 

[vanir]

So I don't at all understand why C3 injection would be preferable to MW-50, except on limited run, early production test engines whilst the bugs are being sorted out.

It's preferable because it means you don't require a separate tank and plumbing for the MW50, which means less weight, or you can carry extra fuel in the place of the MW50, which means more range.

It also doesn't have the corrosive effects on the engine MW50 had.

Blower efficiency is directly proportional to temperature, water injection lowers blower temperatures,

So, as I understand it, did C3 injection.

I'd like to hear how MW-50 corrodes engines also, although I don't necessarily doubt that for some reason unknown to me it did in the Messerschmitts it was installed in. I understand that a combat pilot of 109's referred to this. I just don't understand how it would. Nitrous oxide would damage an engine but MW-50 shouldn't at all (and they do have almost identical plumbing).

Also, as I mentioned C3 is simply a higher octane fuel. It doesn't lower temperatures, any temperatures anywhere in the engine or anywhere else compared to any other gasoline fuels. It burns at higher temperatures.
What this means is operational cylinder temperatures which would significantly and immediately hurt performance and engine reliability with lower grade fuels, does not do so with higher octane fuels. This means you can either run a higher level boost or at higher operating rpm than you otherwise could with lower grade fuels.

But actual blower efficiency at the same settings would deteriorate. A lot of the time though this doesn't matter, because if you put higher octane fuel in a given engine you could get away with putting a bigger supercharger rating on it anyway (higher island-cfm or roots pump rating). The settings when you do this though become very precise because everything's running at higher temperatures and pressures and the whole mess starts to get unforgiving.

An example of an engine treated this way might be the overblown and "bottle boosted" AS series of 109G, with their particularly short operational engine life, but this is speculation. I know relatively little specific engineering details on given models of warplanes.

What I can do is computer model a Merlin 25 I have complete specifications for. I'll get back to you with some results of simulated MW-50 and C3 installations and regular grade fuel.

I'll see if I can find some specifications for DB engines on the web to get it as close a comparison as I can.

 

[KraziKanuK]

vanir,

C3 was injected, not into the cylinder(s), but into the intake induction system upstream as was MW and did exactly the same as what MW50 did.

Btw, Tech Description #284, dated 28.11.44, for the A-8 states "will be produced only with the aux fuel tank". No MW50.

 

[vanir]

KK,
From links you posted:

There were two (2) grades of aviation gasoline produced in volume in Germany one the B-4 or blue grade and the other the C-3 or green grade. Both grades were loaded with the equivalent of 4.35 cubic centimeters tetraethyl lead per gallon. The B-4 grade was simply a fraction of the gasoline product from coal and coal tar hydrogenation. It contained normally 10 to 15 percent volume aromatics, 45 percent volume naphthenes, and the remainder paraffins. The octane number was 89 by a measurement corresponding to the C.F.R. motor method. The C-3 grade was a mixture of 10 to 15 percent volume of synthetic isoparaffins (alkylates and isooctanes) and 85 percent of an aromatized base stock produced by hydroforming types of operation on coal and coal tar hydrogenation gasolines. The C-3 grade was permitted to contain not more than 45 percent volume aromatics. This aromatic limitation sometimes required that the base stock component include some diluents other than the aromatic fraction, which could then be balanced if necessary by the inclusion of slightly more isoparaffin. (The C-3 grade corresponded roughly to the U. S. grade 130 gasoline, although the octane number of C-3 was specified to be only 95 and its lean mixture performance was somewhat poorer.)

And MW-50 is a water injection system which is completely different, operates completely differently and its function is completely different.
Let me paraphrase the above paragraph for you. You drain your fuel tank of B4 standard grade aviation fuel. You refill your fuel tank with C3 high octane aviation fuel. You aircraft is now C3 injected.
You yourself wrote:

C3 is the German designation for their 'high test' fuel. B4 is the designation for 'regular' grade fuel. 190s with the BMW801 required C3 grade fuel.

Which led me to think you understood how it worked. I know how that works. I'm not trying to be rude, just stating the facts. Trust me, the basic engineering principles apply whether a car or aircraft engine. High octane fuel is high octane fuel and water injection is water injection. They are different.

I appreciate the confusion that they may address a similar issue with engines: fuel predetonation. Performance motors that overheat do it and motors with too much boost, incorrect tuning or overmodification do it. Mosty it's about cylinder temperatures.
But the way they fix it is as different as they are. Water injection cools the cylinder temperatures. Higher octane fuel doesn't predetonate until a higher temperature in the first place.

So, on an air cooled Fw190 it is obviously better to run the highest octane you can get your hands on. It's like a Porsche 911, sit at the lights too long and the motor starts pinging. Air cooled. An Fw190 under certain conditions may easily overheat. MW-50 is a good emergency measure but it's better as a power enhancement. If a given Fw190 has a tendancy to overheat under normal conditions, higher octane fuel or improved cooling is a must.

More about this comparison in my test model of a DB605 I did last night.
_________________________________________________________

Ran some models to compare MW-50 with C3 injection and standard M4 grade gasoline. 35 litre simulated DB605 engine based on a Merlin 25 shell (fuel injection added, supercharger specifications revised to listed and other data modified to suit).

First let me say the two engine models are like comparing small block to big block V8's. Very different, the DB makes around 30% more torque almost right off idle to the Merlin and produces horsepower much more easily, with very lazy cam grinds.

But the DB needs at least 2-5 degrees timing retard if it's not going to start snapping conrods so it loses a couple of hundred horsepower right there. On M4 grade gas. So where it should be producing around 1700hp it actually produces more like 1475hp but it's got over a thousand horsepower almost coming off idle, so that makes a big difference. The Merlin has more output...the DB is a more powerful engine. Funny the way that works, huh?

So there's where the climb rate of 109's comes in. It's not that they can actually do more than say, a Spitfire in a prepared race at maximum outputs, it's that in actual combat conditions they're already moving air more easily to start with. They've got an inherent head start that might not show up on listed maximum specs but would be known by experienced combat pilots.

Use C3 test fuel (high octane) and the knock index drops so low you can advance the spark curve right back up to get the engine's producing 1600hp by 2400rpm. With a bit of tuning, leaning it off and a few adjustments here and there you'll be getting that 1700hp at 2800/1.42ata that you should and better fuel economy to boot.
Volumetric efficiency has marginally dropped however (engines should be built for the fuel they'll be using from scratch), but still far exceeds that of the Merlin.
With this fuel the blower should really be adjusted or even changed.

Now switch back to a straight MW-50 fitment on M4 fuel. First the knock index with this stuff drops so significantly you've got to lean the mixture right off from the cockpit or you'll flood the engine. Perhaps the system includes this adjustment as part of engine management (it'd be smart if it did). Spark advance can proceed to best output. But 1900hp emergency power is no sweat. You can make 1800 climbing power if you want and you don't have to play around with camshaft profiles like you should for C3. And volumetric efficiency is improved over the standard engine. The blower should really be changed to the 25% larger AS variant if this engine will use MW-50 frequently under combat conditions, for best results. It'll break 2000hp easy in that case but will need a little babying when the water injection's not running (tendancy to overheat, predetonation, etc.).

This is with ideal computer modelled test conditions at sea level and intended only as a rough guideline for comparisons between higher octane fuels and water injection on large, blown motors, and some general engine characteristics.
Unfortunately I couldn't model GM-1 fitment due to problems with my graphics client in the program.

 

[lesofprimus]

Excellent and interesting post dude... We need to get you and soren together....

 

[KraziKanuK]

vanir,

MW50 only cools the cylinders indirectly because the fuel mixture in the induction system has been cooled by the injection of MW50.

Inject any fluid into the front end of the induction system and the fuel mixture temperature will be lowered by vaporization.

Btw, the British carbs did the same thing, lower the fuel mixture temperature(slightly). Have you not heard of carb icing? Even cars can have icing problems.

You are confusing 'fuel injection'. The Germans used direct fuel injection and I agree that 'injecting' more fuel at the cylinders is of no help. Inject it at the front end of the induction system, which BMW did for the 801, it acts the same way as MW injection. C3 injection uses the same plumbing as MW injection.

Maybe this link will help with your confusion, www.forums.ubi.com/eve/ubb.x/a/tpc/f/63110913/m/9991053533/r/5711054833

 

[vanir]

vanir,

MW50 only cools the cylinders indirectly because the fuel mixture in the induction system has been cooled by the injection of MW50.

Inject any fluid into the front end of the induction system and the fuel mixture temperature will be lowered by vaporization.

Btw, the British carbs did the same thing, lower the fuel mixture temperature(slightly). Have you not heard of carb icing? Even cars can have icing problems.

You are confusing 'fuel injection'. The Germans used direct fuel injection and I agree that 'injecting' more fuel at the cylinders is of no help. Inject it at the front end of the induction system, which BMW did for the 801, it acts the same way as MW injection. C3 injection uses the same plumbing as MW injection.

Maybe this link will help with your confusion, www.forums.ubi.com/eve/ubb.x/a/tpc/f/63110913/m/9991053533/r/5711054833

KK,
The link doesn't work for me, however this one click me clearly shows the location of the direct injection's fuel injectors.
The BMW 801 does not use any kind of injector plate as you suggest. It is not a throttle-body injection system, that is injectors mounted prior to a plenium chamber or ahead of the port runners but is a direct injection system, that is, individual injectors squirt right into port runners or cylinders.

Okay. Using fuel as a charge-coolant is a bit flawed, though I appreciate the logic behind your suggesting it.

Firstly, in a hypothetical case of adding additional fuel injectors "upstream" to an existing fuel system, more fuel in the same amount of air means you're simply richening the mixture. Doesn't matter where you're doing it, you're retuning the engine. So unless you're going to come up with a proportionate amount of increased air intake all you're doing is throwing the motor out of tune. Big time.
But don't get me wrong, richening the mixture is the first thing you do when your motor starts pinging. Say your Fw190 gets a little hot coming in for a landing and starts to splutter when there's plenty of fuel on the guage...richen it up, so it doesn't stall if you've gotta suddenly open the throttle and do a flyaround. I'm talking about an 8th turn on the knob or a quater inch on a lever here, not shoving in a whole 'nuther set of injectors.
Mixture settings are pretty important. Air-fuel ratio. Once again this is as a "just in case that's what you meant, or would say next."

But there is one system which does in fact include an additional set of gasoline injectors, usually placed in the manifolding kinda like you suggested: nitrous oxide.
This is for the same reason, in reverse. Nitrous has no fuel burning value. None. All it does is puts a super-condensed charge of oxygen into the intake. So you have to put more vastly more fuel in when it's switched on, hence the extra injectors. They switch off again when you turn the nitrous off.

Next thing. Fuel already does the best thing it can do to cool cylinder temperatures (because that's what causes predetonation rather than intake temperatures, which affect volumetric efficiency), with the lead put in it. This is the sole and entire reason there is lead in leaded gasoline, to cool cylinders down quickly for the next intake stroke. That's because if they can't cool the cylinder temperatures down, the next intake charge is going to explode whilst it's still coming in.
Lead in gasoline takes some of the cylinder temperature out the exhaust valve.

So even though it isn't exactly what you suggested, you can in fact increase cylinder cooling by putting in more lead via increasing fuel intake...but you throw the engine out of tune (ie. it won't even run). Or you can increase the amount of lead in the same mixture of fuel...but then it won't atomize or burn properly so your engine won't run.

How about moving the injectors completely to a throttle-body setup (as per say, blow-through carburettored induction only this is an injector plate, so the supercharger heats up air by compressing it and then you squirt mmm...nice cold fuel into the air ahead of the port runners)?

Cooling the intake charge does improve volumetric efficiency and helps a little with cylinder cooling, especially if the resultant mixture is not vapourised but atomized (ie. still little tiny droplets).
But using fuel to cool the intake charge will vapourise rather than atomize the mixture as it absorbs heat and reduce its ability to cool the cylinders upon entry (picture scalding hot steam for effect...doesn't cool stuff down much...but that is a statement for illustrative puposes alone). And worse than that, cooling anything via heat induction doesn't work if the heat doesn't go anywhere. It just gets carried by the lead in the vapourised gasoline directly to the cylinders, which is precisely what the stuff was designed to do. It will initally cool the charge itself, hell it'll vapourise nicer and fill the now even hotter cylinders with that much more air-fuel mixture. Problem is the cylinders will be hot, every cycle it'll be burning a little more mixture than it would've otherwise so it'll get even hotter, you'll be putting vapourised and not atomized mixture, which is just dying to immediately explode, carrying heat from the induction system and supercharger directly in there and in no time it'll start to go bang before the spark plugs tell it to.

Direct injection is widely known for its improved characteristics towards predetonation. Multipoint injected engines use much higher compression ratios than carburettored ones at the same fuel octane. This is because the fuel is atomised by the injectors upon entry, carrying as little residual heat as possible into the cylinder, absorbs some of the residual cylinder temperature vapourising upon entry and is quickly burned and the lead is thermally free to carry some of the produced heat away from the cylinder walls via induction, out the exhaust port.
Before direct fuel injection you just plain had to lower the compression ratio from optimum on any hardworking gasoline engine.

Air charge coming into the system is heated by superchargers through either being compressed (impeller types), or being blown in under pressure (screw types, which have their own heat problems but if you can keep them cool they atomize draw-throughs beautifully). Whilst any freely inductive materiel injected into the airflow after the supercharger will dramatically help cool oxygen intake charge (moreso than intercoolers alone), using gasoline to do it will either or both:
a) throw your mixture out of whack
b) carry the heat to the cylinders in the lead
In draw-through systems the injected fuel is being used to cool the supercharger itself, which is almost necessary for a screw-type as it increases its notably poor efficiency. But the charge is all hot coming out the other side so you still need some kind of intercooling and preferrably, water injection to avoid those predetonation problems. Impeller types, as used on German engines are usually oil cooled so heat isn't as much of a problem, but the charge compression of that kind of supercharging is going to put heat in the mixture anyway so that's no good for cooling the intake. It's going to:
a) reduce the capacity of the mixture to cool the cylinder by vapourising instead of atomizing it
b) carry the heat produced in supercharging right to the cylinders in the lead.

Now don't get me wrong, if you had to make do without direct injection like the Merlin did there's things you can do to lessen the impact. But you wouldn't switch back to the worse system from the better to get more power or improve engine characteristics, it's quite the opposite.

Using water is a great idea. Just behind the supercharger is right where Germans put MW-50 injection. Water vapourises freely so it conducts the heat from the incoming oxygen charge, it doesn't have lead to induce it back into the cylinders when it gets there, injected atomizing fuel doesn't get a chance to vapourise prematurely itself and it doesn't adversly affect the tuning of the engine, providing only a minimal oxygen increase which isn't such a bad thing with a lower knock index anyway.
You put methanol in the water so it doesn't freeze when you climb to 20,000 feet and Bob's your uncle.

So *broken record time* C3 does nothing to reduce the cylinder temperatures and prevent predetonation. It simply burns at higher temperatures. Water injection lowers cylinder temperatures. It is cylinder temperatures which causes the problems with engines like the BMW 801, DB605, Porsche 911 Turbo, your old man's Jaguar, etc.

I do however, appreciate your time and logical thinking on the matter. Engineering high performance motors can be tricky and is a road of dead pilots and lessons learned by trying.

 

[Hop]

Vanir, are you claiming that C3 injection wasn't used? The original documentation shows it was.

To quote from an allied description from captured aircraft:

"Extra Emergency Performance (Fuel injection into air intake)

This system is used on the BMW 801 D to increase the emergency performance. It provides for the overriding of the boost regulator and the simultaneous injection of C3 (96 octane) into the port air intake to prevent detonation and provide internal cylinder cooling."

further on:

"The second cock opens a pipe line from the fuel pump to a spray nozzle fitted into the port air intake. The spray nozzle is calibrate to pass 14.3 +- 1.43 gallons per hour at a pressure of 18 to 25 lbs sq in"

 

[vanir]

Okay this is getting boring now.

Vanir, are you claiming that C3 injection wasn't used?

That's right. I'm claiming martian soil was used to strengthen German airframes.

The original documentation shows it was.

No it doesn't. It shows C3 fuel was used. C3 is a fuel. F-u-e-l. I've been reading quite a bit about the BMW 801 in the last few days.

To quote from an allied description from captured aircraft:

And here is a link for the allied report on engine testing the BMW 801:
http://naca.larc.nasa.gov/reports/1945/naca-wr-e-192/
It doesn't mention anything about a special injection system some of you seem to have assumed the D variant of the BMW 801 sported. But it also doesn't mention the length of Bugs Bunny's ears.
Yours is anecdotal and mine occidental. Engine blueprints show no additional fuel injection system was used in the air intake nor anywhere else.

"Extra Emergency Performance (Fuel injection into air intake)

He might as well have called it Super-duper power producer. The allusion is clearly incorrect, port injection is a LONG way from the air intake for a start. It's just outside the cylinder.

This system is used on the BMW 801 D to increase the emergency performance. It provides for the overriding of the boost regulator and the simultaneous injection of C3 (96 octane) into the port air intake to prevent detonation and provide internal cylinder cooling."

Yeah compared to the carburettors on Merlins maybe. Context is important and this guy is obviously comparing direct injection to carburettors.

How many ways can I put it? Fuel injection at the AIR intake does not cool down cylinder temperatures, I've already mentioned this. PORT injection is not fuel injection at the air intake.
The bit that says "to prevent detonation" is the higher octane rating of the fuel. The bit, "to provide cylinder cooling" is just a general reference to direct injection systems as opposed to carburettors or throttle body fuel intake, he's giving a general description of multipoint fuel injection, also known as direct injection and may be at the port, intake manifold or cylinder. If it was cylinder injected he'd be saying, "to provide cylinder cooling," precisely as he did for port injection. If it was manifold injected he'd be saying, "to provide cylinder cooling."
Say hello to direct injection vs other fuel delivery systems.

And how many ways can I put this part? C3 is not a fuel delivery system it's a fuel (95 min. octane motor method or as high as 130 rated octane at the pump).

Your out of context insinuation is that the BMW 801D used a special fuel injection system in conjunction with this fuel. It did not. It used precisely the same fuel injection system as all BMW 801 model radial engines.

So once again, here's some additional background for you. Daimler Benz used cylinder fuel injection. BMW used port injection, which is about four inches further back. It has absolutely no opportunity whatsoever to cool intake charge. It does not reduce cylinder temperatures any more than cylinder injection. Both are direct fuel injection systems. It does create a low pressure area at the ports for uncooled air intake charge but the DB system gets slightly more immediate throttle response and better cylinder fill.
Port injection is not at all unique to the 801D nor C3 fuel.

"The second cock opens a pipe line from the fuel pump to a spray nozzle fitted into the port air intake. The spray nozzle is calibrate to pass 14.3 +- 1.43 gallons per hour at a pressure of 18 to 25 lbs sq in"

It doesn't say secondary spray nozzle and doesn't have to be read that it does. Perhaps if you post a link to the document I'll be able to tell you what is meant by "second cock" on the fuel pump valve, I'd say one drives a mechanical fuel pump and the second opens the valve, from here.
If the BMW 801D had a secondary fuel injection system installed I should think this would have been mentioned on at least one document I have read or I should be able to find it on the engineering blueprints for this engine. No on both counts.

It is possible to arrange a secondary fuel distribution in injection, similar to the vacuum or mechanical secondaries available on carburettors. However this MUST be combined with an increase in air intake volume (not just boost pressure) and no such modification for this is listed nor appears in BMW 801D engineering renditions either.
I understand such a system is the assumption of some of you. It is simply misguided by out of context statements and poor descriptions.

{It is also a common fallacy by V8 owners that Spreadbore carburettors with secondaries fitted are a high performance carburettor. They're not, Squarebores without secondaries are but they guzzle juice at part throttle applications.}

It is clearly stated in several documents relating to the BMW 801 series engines that the D variant did not change or alter its injection system to any other variant but simply used a higher octane fuel.
When you do that, you can change your boost settings. That's how they got more power.

Wanna know how? You get the boost regulator and a hacksaw...

 

[Gille]

Vanir

Nothing Hop says is in the slightest bit controversial for those familiar with the FW190A.

MW-50 was tested in the 190A but it was discovered that direct injection of C3 fuel (a secondary line was run from the main tanks) was more efficient as a charge coolant than methanol-water. It also had the advantage that it did not require a special tank to be installed.

C3 injection (C3-Einspritzung) was first fitted to 190A-5 jabo's, it could only be run in first supercharger gear and it allowed the engine to be run at 1.58ata boost.

The first standard fighter variant to receive the system was the A-8, in this variant the system could be used at all altitudes, it allowed 1.58ata boost in the first supercharger gear and 1.65ata in the second. Speed charts for the A-8 and A-9 show this extra boost level.

The German name for the extra boost that could be run while the engine was cooled by this system was "Erhöhte Notleistung" (extended emergency power). If you google using this term you will find a lot of discussion on the various specialist aviation boards and sites regarding this system. Alternatively you can look at the Flugzeug Handbuchs for the A-5 to A-9 where a description of the system is included (Teil 7, page 31 of the A7-9 guide).

 

[KraziKanuK]

vanir,

yes it is getting very boring because of you.

You had better do some much more reading and also contact White 1 Foundation.

Btw, your link only mentions the Fw190A-1, A-2, A-3. No mention of the BMW 801TU or later 190 models. You should also get hold of Fw190 Modification Instruction No 133. If no such system was installed then why are 3 different sparkplugs listed as to be used when installed? The 801C in the A-1/A-2 used B4 fuel.

Care to explain the following for a D-2 engine, if C3 injection was not used. This is not the injection of C3 fuel to make the engine run.

Fw190 2700 rpm / 1.42 ata BMW801D2 without C3 injection
1800 PS sea level
1490 PS 19028 feet
341 mph sea level
400 mph 20770 feet

Fw190 2700 rpm / 1.58/1.65 ata BMW801D2 with C3 injection (10 minutes)

2050 PS sea level
1695 PS 19028 feet
359 mph sea level
405 mph 18044 feet


Just in case you missed what Gille (a quite knowledgeable person on the 190) posted,

MW-50 was tested in the 190A but it was discovered that direct injection of C3 fuel (a secondary line was run from the main tanks) was more efficient as a charge coolant than methanol-water. It also had the advantage that it did not require a special tank to be installed.

So vanir, when are you going to admit you did not have a clue after all your long winded text diarrhea?

 

[Hop]

Okay this is getting boring now.

Vanir, you've got a theory that injecting fuel ahead of the supercharger isn't going to provide usefull charge cooling, and therefore it wasn't used. In fact it was, it was used in later 190s to enable extra boost, it was also used in Merlins throughout the war for it's charge cooling effects.

When a theory says that something won't work, and history says it did work, it's time to re-examine the theory, not to try to change history.

No it doesn't. It shows C3 fuel was used. C3 is a fuel. F-u-e-l. I've been reading quite a bit about the BMW 801 in the last few days.

190s used C3 as fuel for almost the entire war. Fairly late in the war they began injecting the fuel into the air intake ahead of the supercharger for it's charge cooling effects, that's what "C3 injection" describes.

Engine blueprints show no additional fuel injection system was used in the air intake nor anywhere else.

Try looking at the correct blueprints.

He might as well have called it Super-duper power producer. The allusion is clearly incorrect, port injection is a LONG way from the air intake for a start. It's just outside the cylinder.

No, he means port as in left, as in the opposite of starboard. Fuel was injected into the left air intake.

Yeah compared to the carburettors on Merlins maybe. Context is important and this guy is obviously comparing direct injection to carburettors.

No, he's comparing the 190 to the later 190 with fuel being sprayed into the air intake.

Read the description. "a pipe line from the fuel pump to a spray nozzle fitted into the port air intake. The spray nozzle is calibrate to pass 14.3 +- 1.43 gallons per hour at a pressure of 18 to 25 lbs sq in"

Do you think he's imagining that?

How many ways can I put it? Fuel injection at the AIR intake does not cool down cylinder temperatures, I've already mentioned this

Well, the engine designers of the time thought it did, obviously you are more experienced in this than they were. And to think this useless C3 injection system was used, when they could have been running at 1.65 ata boost all along without it. Silly BMW.

PORT injection is not fuel injection at the air intake.

It's injection at the port (left) air intake.

The bit that says "to prevent detonation" is the higher octane rating of the fuel.

No, C3 has the same octane rating whether it's injected into the air intake or directly into the cylinders. But directing it into the air intake provides charge cooling, which allows higher boost without detonation. That's why they did it.

The bit, "to provide cylinder cooling" is just a general reference to direct injection systems as opposed to carburettors or throttle body fuel intake, he's giving a general description of multipoint fuel injection, also known as direct injection and may be at the port, intake manifold or cylinder. If it was cylinder injected he'd be saying, "to provide cylinder cooling," precisely as he did for port injection. If it was manifold injected he'd be saying, "to provide cylinder cooling."
Say hello to direct injection vs other fuel delivery systems.

So why the nozzle injecting 14 gals an hour into the air intake? How do your theories account for it?

And how many ways can I put this part? C3 is not a fuel delivery system it's a fuel (95 min. octane motor method or as high as 130 rated octane at the pump).

Hence the term C3 injection

Your out of context insinuation is that the BMW 801D used a special fuel injection system in conjunction with this fuel. It did not. It used precisely the same fuel injection system as all BMW 801 model radial engines.

I won't go into which 801 variants used C3 injection, because I don't know, I do know it was used on later 190 A variants, I think on d9s as well.

Are you saying all 190s had a fuel nozzle spraying into the air intake, operated by a valve in the cockpit? Or that none did?

Clearly the late war ones with C3 injection did, those without C3 injection didn't.

BMW used port injection, which is about four inches further back. It has absolutely no opportunity whatsoever to cool intake charge.

I have no idea where BMW injected fuel into the engine, I assumed it was directly into the cylinders. But I do know that the C3 injection system used a nozzle to spray fuel into the air intake. The port

intake, to be exact.

It doesn't say secondary spray nozzle and doesn't have to be read that it does. Perhaps if you post a link to the document I'll be able to tell you what is meant by "second cock" on the fuel pump valve, I'd say one drives a mechanical fuel pump and the second opens the valve, from here.

No, the first one opens an air bleed into the boost pressure regulator, causing the regulator to open the throttle to provide up to 1.65ata, instead of 1.42 ata. It has nothing to do with the fuel system.

It's alluded to in the first paragraph, that I already posted:
"It provides for the overriding of the boost regulator and the simultaneous injection of C3 (96 octane) into the port air intake to prevent detonation and provide internal cylinder cooling."

The first cock over-rides the boost regulator, the second sprays fuel into the air intake.

If the BMW 801D had a secondary fuel injection system installed I should think this would have been mentioned on at least one document I have read or I should be able to find it on the engineering blueprints for this engine. No on both counts.

Then you need to read more. Abscence of evidence is not evidence of abscence.

As to engine blueprints, it was a system fitted to the aircraft, not the engine, so probably wouldn't show up on engine blueprints.

I understand such a system is the assumption of some of you. It is simply misguided by out of context statements and poor descriptions.

It's a matter of historical record.

It is clearly stated in several documents relating to the BMW 801 series engines that the D variant did not change or alter its injection system to any other variant but simply used a higher octane fuel.

The problem with that is C3 was the standard fuel for the 190 in the earlier A variants as well. Even Faber's A3, captured in summer 1942, was running on C3.

When you do that, you can change your boost settings. That's how they got more power.

Wanna know how? You get the boost regulator and a hacksaw...

Or you operate the lever that opens the first cock that bleeds air into the regulator allowing the throttle to open more fully allowing higher pressure.​

 

[DerAdlerIstGelandet]

Good discussion here and good links to all of you. Learning some new stuff about the system as a whole.

 

[vanir]

sorry I got a bunch of posting errors that reposted ridiculously and went stupid on my computer.

 

[vanir]

lalala

 

[vanir]

yep it just plain kept reposting and telling me it was in php debugging mode.

 

[vanir]

Vanir, you've got a theory that injecting fuel ahead of the supercharger isn't going to provide usefull charge cooling, and therefore it wasn't used. In fact it was, it was used in later 190s to enable extra boost, it was also used in Merlins throughout the war for it's charge cooling effects.

I'd like to mention I appreciate basic engineering principles being attributed to theories of mine, however injecting fuel ahead of the supercharger cools the supercharger and heats the mixture.
Look, I think you don't know what you're talking about and telling me the sky is green. I apolegise...however that is what I'm thinking.

The engineering facts are no fuel delivery at the air intake was used on any BMW 801A-D series engines whatsoever. None of them. I don't think it was used on any 801-series engines at all, including bomber variants. Please provide engineering blueprints, specifications or papers which say otherwise. I've got ones which don't. Argue with proof so that I may physically see where I have it wrong and apolegise.

It was not used on Merlins for charge cooling effects. Merlins used carburettors because they did not develope fuel injection. There was no other reason. The only reason I'd put carburettion on a draw-through centrifugal supercharger is for convenience or carb insulation. It'd get more horsepower closer to the head.

When a theory says that something won't work, and history says it did work, it's time to re-examine the theory, not to try to change history.

History doesn't say it did. You do. You've so far offered no corroberative evidence to support these claims. Anecdotal evidence simply won't do for supporting claims which challenge engineering principles and printed technical documents. If you'd like to suggest an additional fuel delivery system to the BMW 801D in Fw190's which does not appear on technical specifications and documentation please provide some clear evidence for it.

Fairly late in the war they began injecting the fuel into the air intake ahead of the supercharger for it's charge cooling effects, that's what "C3 injection" describes.

Nothing I've seen documents this. There is no reason to think a system which appears nowhere but the claims of a couple of individuals should exist where it does not on any technical documentation. Please provide proof.

BMW 801D's used C3 fuel. This whole "C3-injection" thing, without any corroberative evidence of a technical nature is equivalent to an urban myth.
The reason the 801D used C3 fuel was because they were trying to get more power out of it and didn't want it predetonating. I've already explained how this works. No additional fuel injectors nor even air intake volume is required. But if you did one, you'd have to do the other and then re-evaluate your supercharger for size and specifications. There's no way around this, it's a fact.

Let's be very clear on what your utterly unsupported claim is:

1. that the BMW 801D used C3 fuel. Yes that is supported by corroberative evidence.

2. that the BMW 801D in the Fw190 used an additional fuel injection system mounted at the engine air intake (on the port side) at emergency power settings. No that is not supported by any corroberative evidence whatsoever. Just to be clear, easily misinterpretive anecdotal evidence is not corroberative evidence. You did have corroberative evidence before you made this assumption?

3. that the system "..opens an air bleed into the boost pressure regulator, causing the regulator to open the throttle to provide up to 1.65ata, instead of 1.42 ata." No that's an incorrect description of how a boost pressure regulator works. Look back over the last part or learn about superchargers, fuel delivery systems and boost regulators.
If you've quoted from a source, please provide the link so I can tear apart the author's obviously questionable knowledge. For example:

Or you operate the lever that opens the first cock that bleeds air into the regulator allowing the throttle to open more fully allowing higher pressure.

That's just not how boost pressure regulators work. You said, "it has nothing to do with the fuel system." I say, it has nothing to do with "the throttle opening more fully."

4. that this is system was introduced to improve cylinder cooling and prevent predetonation at emergency power settings. No that is incorrect according to motor engineering principles. Ask around at your local race track if you prefer anecdotal evidence to engineering specifications.

The following is quoted from the very first link in a Google-search for draw-through supercharger cooling and a bit of site navigation. It must be mentioned that screw-type roots superchargers like GM and B&M performance ones available today work completely differently to centrifugal or compressor-type superchargers used in BMW, DB and Merlin fighter engines.

Although many roots and twin screw superchargers bolt directly to the manifold, most centrifugal superchargers require an extra tube called a Discharge Tube to carry the air to the intake {edit: ie. the HEAD PORTS} through the throttle body.

This is the type of supercharger used on the BMW 801-series.

Some supercharger systems include an aftercooler (more commonly called an "intercooler"). Superchargers heat air as it is compressed. Although the intercooler is not necessary on most street applications, its performance becomes increasingly important on higher-output systems (with correspondingly higher charge temperatures).

This problem is accentuated by the radial engine being air cooled in the first place.

An aftercooler is a heat exchanger placed between the compressor and the engine's inlet. Vortech uses the term "aftercooler" as we feel it is more accurate; it is "after" the compressor. "Intercooler" means a heat exchanger placed between two compressors in a multi-stage system, but has been used as a synonym for an aftercooler ever since it was incorrectly stuck on the backend of a Volvo in about 1981. Aftercoolers and intercoolers are both also called charge coolers.

Intercooling and aftercooling may also be provided by water injection in the discharge piping.

For heat exchanger design purposes, the gases in air are classified as a low-density fluid. Air going through a supercharger is called "charge air". A supercharger compresses the charge air before it enters the engine. The act of compression both increases the energy and density of the charge air, but this act also generates a proportionate amount of heat. Heating is undesirable, as it tends to decrease the density of the charge air.

Using fuel delivery at the air intake increases the density of air, causing a proportionate increase in temperature above and beyond the original air-charge compression. Even if it's say 10 degrees cooler going in because you decided to mount a draw-through carburettor like Merlin did, it ends up 50 degrees hotter coming out the other end than it would've otherwise, due to the increased density. As I mentioned, with leaded fuels the problem is compounded by the lead in the fuel which holds onto that heat rather stubbornly during any subsequent "intercooling."
{sidetrack: How did Supermarine fix this? High island-cfm superchargers that compress less harshly for a given boost rating (but work better at higher altitudes than they do at low ones). A minimum 104 octane fuel (approx. 96 min. motor method octane as compared to C3's 95). A higher operating rpm permitted wider duration cam grinds and therefore lower dynamic compression ratio at the same static rating. And big banks of intercoolers and radiators (the equivalent to what Messerschmitt used for 87 min motor method octane fuel at the same static compression ratio and a 21 psi boost emergency pwr/19psi climbing pwr).}

*broken record time* using additional fuel delivery into the air intake system does not reduce predetonation. What it does is richens the mixture of air-fuel charge entering the engine, thereby throwing your engine way out of tune. How are you going to account for this, invent a secondary air-intake throttle body somewhere on the engine as part of this magical mystery "C3-injection system" ? It's getting bigger and more complicated with every post.

Try looking at the correct blueprints.

Try posting, displaying or linking to any blueprints at all.

No, he means port as in left, as in the opposite of starboard. Fuel was injected into the left air intake.

Not according to the pictures, one of which I posted a link to in pdf format. You can tell it's the fuel injector because it has a little arrow to it marked "fuel injector." You can tell it's the C3 fuelled engine from an Fw190 because it has bold print that says "BMW 801D engine."
It clearly shows the fuel injector is at the cylinder head and nowhere near the air intake for the engine. That is more in concordance with head-port intake than left air intake.
Mate, the blueprints support what I'm saying, and challenge what you say, which appears based solely on one piece of dubious anecdotal evidence.
You may be great at arguing for the sake of itself, but your argument isn't supported by any credible data.

No, he's comparing the 190 to the later 190 with fuel being sprayed into the air intake.

How do either of us really know he wasn't comparing it to the Space Shuttle. Yes, he was a seer, a Celt and a magician. He's right here in fact and he wants his pointy hat back.
Your argument is somewhat less than compelling.

Read the description. "a pipe line from the fuel pump to a spray nozzle fitted into the port air intake. The spray nozzle is calibrate to pass 14.3 +- 1.43 gallons per hour at a pressure of 18 to 25 lbs sq in"

Do you think he's imagining that?

No I think you're making a completely unqualified assertion based on what you've decided to assume without cross-referencing and seeking to correlate your data. If you could show me a picture of this system you've imagined at the engine air intake, I'd really appreciate it. I think it was simply a poor description when what was meant was head-port intake. That one thing would explain everything (occam's razor anyone?).
I didn't decide to think this, I was led to this consideration by physically looking at the engineering blueprints for myself. I originally thought it meant precisely what you do, but knew from personal experience this didn't make any sense. I've tried mounting fuel delivery a foot and a half from the head, I've tried it a few inches away, I've pulled down the head to get 3hp by changing the finish on the ports, I've found 10hp from properly mounting a bonnet scoop and custom made manifold heat plate, all to get a 3-litre race engine to beat 5 and 6-litre race engines in the same class. So I looked it up. I checked. As it turns out the allusion of the source materiel you're using appears to be wrong and any direct assumption from it out of context.

Like I said whoever wrote it should get a good slapping. It's not your fault or mine, I don't seek to blame you for it. But you've continued to argue with me a second time obviously without even checking up on a claim you appear to have simply assumed from one or a number of uncorroberated, anecdotal, unknowledgable or out of context sources. If I am wrong in this assertion, please provide the evidence so that I can see the error of my ways and experience.

Even the statement itself doesn't make any sense, doesn't that bother you? It doesn't make any sense because the only fuel injectors are clearly shown on the blueprints for the BMW 801D and they are at the head ports. But you haven't bothered to look those up or find me ones which show otherwise.
It doesn't make any sense because the BMW 801D did not have multiple air intakes or throttle bodies, it was not a twin supercharged engine, it only has one air intake for the engine so why specify a "port" air intake? It makes sense if what should have been written was "port intake."
What annoys me is that your entire argument, which is full of engineering flaws and that Sir most certainly is a matter of physical example, appears completely based on this one piece of anecdotal rendition.
Post some proof, it's somewhat more conductive of interactive relationships between active minds than sitting here picking each other's posts apart.

It's a matter of historical record.

Mate, saying things like that as an argument is just childish where you don't provide the proof so that we may both observe it together.

Here's what I think. Some airman or even a foreign pilot, who'd spend half a day looking for a left-handed wrench saw an MW-50 injection system and had no idea what he was talking about, then a few people including at least two in this thread took his anecdotes as gospel. Either that or due to a complete lack of any personal knowledge of the systems involved you simply took this anecdotal evidence completely out of context.

That assertion makes sense, it fits the description and it matches the blueprints.

 

[Gille]

I'm too lazy to reinvent the wheel and go and scan all the original C3-injection documents, so I'll just post a link to a post by Kettenhunde at IL-2 forums that contains a couple of the relevant ones:

http://forums.ubi.com/groupee/forums/a/tpc/f/63110913/m/9991053533/p/9

There's also an article from earlier this year on MW-50 and C-3 injection testing in the 190A from a German aviation magazine floating around which documents why they went with the C-3 injection instead of MW-50. I posted a link to scans of it over on LEMB but it got lost with the recent big crash, don't suppose anyone kept a copy?

 

[vanir]

Here is a statement from http://www.focke-wulf190.com

Der 801 D und G wurden als leistungsgesteigerte Version entwickelt. Die Leistungssteigerung erfolgte durch eine geänderte Laderübersetzung und eine höhere Verdichtung in Verbindung mit 95 Oktan Kraftstoff. Die erreichte Leistung lag bei 1270 kW (1730 PS) bei 2700 Umdrehungen pro Minute. Der Ladedruck stieg auf 1,39 bar abs. (abs.= absolut), gegenüber den 1,27 bar abs. bei dem A, und die Volldruckhöhe lag bei 5700 m.

As you can see it clearly states the BMW 801D achieved its higher output through the use of greater supercharger gearing and a higher static compression ratio for which it required the use of C3 fuel.

Here from Wikipedia:

These were soon replaced with the 801D series engines, which ran on C2/C3 100 octane fuel instead of the A/B/C's B4 87 octane, boosting takeoff power to 1,700 hp (1,250 kW) in the D-1, and 1,730 hp (1,270 kW) in the strengthened D-2. The D models also included a system for injecting a 50-50 water-methanol mixture (known as MW50) into the supercharger output to cool the charge, and thereby reduce backpressure. Although practically every production model 190 included the 801D engine, it was not until very late in the war that the MW50 kits were actually supplied and available.

The fact that it didn't mention any different fuel injection system between the C3 injected and M4 injected variants is what initially pricked my interest and led me to continually check further, more technical source materiel.

Other various sources say things like:

The BMW 801D was a 14 cylinder, twin-row radial with direct fuel injection.

Wow, direct fuel injection. Not at the left hand side air intake. Hang on, must be a different engine...nope it's the C3 injected 801D.

This one's a beauty, from the university of western ontario. It basically says "You're wrong mate."

Beginning in the spring of 1942, series production of a more powerful engine version BMW 801D-2 that replaced previous versions in the Fw 190Fighter created a new plane version designated as Fw 190A-3. The increase in the BMW 801D-2 engine power (to 1730 kW) was due to a higher compression ratio and higher pressure two-speed compressor. A higher compression ratio and charging pressure made it necessary to use high-octane (96 octane) C3 fuel in place of B4 (87 octane) fuel.

I dunno, what can I tell you Hop? Check first, then b*tch-slap me.

 

[Gille]

Actually I did have a copy of that article to hand:

http://img178.imageshack.us/img178/7306/klassikerdieleistungssteigerun.jpg
http://img178.imageshack.us/img178/7471/klassikerdieleistungssteigerun1.jpg
http://img178.imageshack.us/img178/4048/klassikerdieleistungssteigerun2.jpg
http://img178.imageshack.us/img178/3692/klassikerdieleistungssteigerun3.jpg
http://img178.imageshack.us/img178/8185/klassikerdieleistungssteigerun4.jpg
http://img178.imageshack.us/img178/365/klassikerdieleistungssteigerun5.jpg