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vanir
04-13-2008, 04:49 AM
Hi.

I'm a bit of a Messerschmitt enthusiast and what I'm not altogether clear on the modelling for the Me-109 series.

Is the E-4 modelled with the DB-601A-1 engine?
E-4/B with the DB-601Aa?
E-7 with the DB-601N?

The E/N (GM-1), listed as the E-7/Z in the American fashion also appears to have some cosmetic issues, as these were based on the basic E-4 airframe most commonly from what I've read (and what my grandmother told me), rather than the E-4/B like the E-7 which was in service alongside it by the end of 1940 (regardless that they frequently shared the DB-601N engine). It was not uncommon for the E/N (GM-1) to be upgraded to E-7 standard (Galland did with his), but the IL-2 model has the E-4/B cockpit (and ground-attack armouring which makes no sense) and yet does not allow a drop tank to be selected at the arming/customising screen. It is an important Emil type being for the first half of 1941, due to the recall of F-1 models it formed the basis of guarding the "Atlantic wall" (until late-41).

The F-series I would like to say is beautifully modelled and I love the addition of both F-2 (601N engine with the new supercharger), and the F-4 (601E engine with the switch back to B4 fuel yet even better performance).

The G-10 I am curious as to which engine is actually modelled. I understand the bulk of its service was with the DB or ASB engine (1800PS). As far as I know it didn't get the DC engine option (2000PS) until the ASC was being fitted to the Kurfurst.

The K-4 I'm curious about also. It appears it is modelled with the DB engine in 1944 form (1800PS) and presumably the DC engine in 1945/C3 form (2000PS).
I've read and heard it was fitted almost exclusively with the 2000PS DC and later ASC engines both using C3 fuel. So of course I'm confused by this modelling also.

I realise the descriptions in the game might not necessarily adhere strictly to the modelling, particularly with the patches, which I why I ask.
The purpose of this posting is also as a form of consumer feedback.

My congratulations on this fantastic product, it is without doubt my favourite computer program of all time.

Cheers, Jason.

JG14_Josf
04-13-2008, 09:08 AM
Vanir,

Can you offer some information on your reading and your grandmother?

Data is scarce so new data is great so long as the new data is accurate. New data that is not accurate is not so great.

As to which engine performance is intended to be modeled in the game I think you will find much in the way of inaccurate data because here too data is scarce.

I would like to read more about your grandmother if it is not too intrusive of me to ask.

vanir
04-13-2008, 04:36 PM
Hello Josf,

To be perfectly honest I cannot personally attest to the voracity of my descriptions as it is second hand and as you mention data is scarce. I've scoured probably many of the same sites as anybody else here, those I've seen links to on these forums.

A good source on the DB-605 is this one, who cites Mercedes Benz AG as a reference, http://w1.1861.telia.com/~u186104874/luftwaffe.htm (http://w1.1861.telia.com/%7Eu186104874/luftwaffe.htm)
I can't seem to find a page I saved listing the Me-109 variants but I have it on wordpad as well, it's a similar sort of site, not a series of engineering blueprints or anything.

But at any rate, right from the word go I grew up under the advisement that Messerschmitt variants were not really so strictly defined as they are in our orderly modern world, the technology was new and factory experimentation and customisation was rife.

I read a very good webpage several years ago my flatmate showed me, which contained an excerpt quoted from a Messerschmitt engineer talking about the Oerlikon fitment to the Me-109 and armament layouts in the Emil. That was fascinating and elaborated some things alluded to by family, plus detailed some early 109 variants which have stuck and help me cull for other accurate sites. Can't for the life of me find that site, I will eventually but it's a matter of wording a google search just right, you know?

The vast bulk of what I find on the web and in publication is very watered down I think, it seems very far removed from the atmosphere I've been brought up to imagine.

My grandmother died many years ago and the very few conversations I had with her and her friends, about the war were over twenty years ago. My anecdotes are more like family stories than war stories. Aside from instilling a healthy skepticism of commercial publications (termed, propaganda), they told me a few tidbits such as Galland's Emil, a custom E-4 given to him by Messerschmitt in 1940, so Galland had the fastest plane in the entire Luftwaffe. It is my personal inference from this the E/N (GM-1) modification was a standardisation of his custom Emil when Friedrich development became protracted coming into 1941 (there was a structural problem).

I also learned about the later models and how they compared to Allied planes over Germany, and how Luftwaffe pilots received the Gustav (good in the Mediterranean, not so good in Europe until later subtypes). We spoke about these things rarely. We were a bit dysfunctional you must understand. I did have the impression my grandmother had a crush on Galland when she was a young lady, but I couldn't even tell you if she ever met him. I asked Gunther several times about his position during the war, he said he was a guard dog trainer. But gave me the rundown on the late model Gustav and the Kurfurst and Allied types over Germany.

My mum said quite seriously once, don't go digging into the past, so I've respected that somewhat. I haven't the slightest idea what my grandmother did in the war.

In short I have little or no documentation you probably don't already have.

vanir
04-13-2008, 05:10 PM
Please excuse my double posting. I've been thinking a little more about what you mean.

Let me just say I've been finding at other forums I've a tendency to annoy a couple of regulars and I don't understand why, so let me just say I don't wish to come across with any kind of smarty-pants attitude.

I did a bit of research and found going the route of hard technical info, documentation and that sort of thing and then being a bit of a detective about it to infer likelihoods has worked to my satisfaction, however controverisal some assertions might seem.

I looked up Luftwaffe squadron listings, where they tell you the lineup of models per gruppe at a given month (say, February 1941, or November 1940 and so on). They list specific variants often. Then I looked up JG 54 losses, which lists specific modifications (such as F-4/B, G-6/R6 and so on). I got JG gruppen descriptions and listings, listing deployments and models for the entire JG history down to staffeln level (for description) and gruppen (for model and deployment by month). I really needed that for IL-2 mission building.
Then I looked up every bit of documentation and research for the engine models from the Rolls Royce Kestrel to the DB-603E which would have gone in the Mustang-like Me-309. I'm really interested in rated altitudes and outputs by engine setting and altitude.
Of course flight test documentation of actual model types is invaluable, and the Germans god love 'em kept records like a religion.

I toss all that with what I've read about gun fitments, any corroberated things I've heard from family, any other miscellaneous credible information and I see what I come up with.

VW-IceFire
04-13-2008, 09:00 PM
Welcome to the forums vanir. Just about anywhere you're going to end up ruffling someones feathers about something...best just to be friendly and be yourself.

Sounds like you have a very solid understanding of the Bf109. I understand what it is to really get to know one particular plane and do some digging to see what you can find about it...my favourites are the Hawker fighters (particularly...and possibly obviously the Tempest) and to a lesser extent the Spitfire and Mustang. I'm still more of a generalist so I like to know allot about allot of planes...but with varying degrees of detail.

The really expert 109 folks around here like Kurfurst and Vike I'm sure will have some interesting conversations with you about the 109. Lots of people have had input into the 109s representation in the game and while all choices will almost always be controversial I think the 109 is amongst the best represented in-game.

vanir
04-14-2008, 12:35 AM
Thanks IceFire, I was here for a couple of visits in 2005 and am glad to be back. I had IL2 standalone back then, added AEP and then bought a merged version IL2+AEP+PF. I love the new 1946 version. I've patched it up to 4.09b and haven't really gotten to know the individual models flight characteristics anew. I'm sure there's been many improvements upon what was already an excellent sim. I'm definitely looking forward to any discussions about the 109 modelling as well as IRL.

I think I have the ICE skin for the Tempest, definitely a hot plane, who'd think a 24-cylinder would rev like that. I also like the way Hawker seems to use knots for their IAS even though they're land based. It's a bit nostalgic I think, kind of nice. I remember doing aeronautics they told us aerial maps were originally made by nautical cartographers, plus it sort of goes with the naval ranking system of the RAF & Commonwealth.

Of course you can't really talk about aerial combat in western Europe without mentioning the Spitfire and Mustang, definitely two legendary marques. From what I've gathered Australia had to wait until 1943 to get Spitfires, the Mark Vc I think, until then Kittyhawks handled the fighter action around here (plus P-400's/P-39's and Buffalos).
Mark VIII's came in 44 I think, which were used in some battles around Indonesia, but post war the RAAF re-equipped with P-51's like many nations.

JG14_Josf
04-14-2008, 12:51 PM
Vanir,

Thanks for the response and good luck with your questions.

vanir
04-16-2008, 02:28 AM
Well, from what I've been able to gather Oleg Maddox neither enters these forums nor would waste much more time with IL2. He's busy with SOW and it is a bad idea to open the code of an online simulator, so I guess all I can do is whinge.

As it is so far I've used the compare software to confirm my assumptions that at least three out of four Emils modelled in IL2 use the DB-601A-1 engine, which is kind of annoying. Firstly, what then is the point of having four Emils? Secondly it is simply inaccurate in regards to the deployment of Emils during 1941 at which time they still formed a very strong Luftwaffe fighter presence. These aircraft, E-7 and E/N(GM-1) types should have improved performance, notably climb rate and operating rpm. Also the E-4/B should really have the 601Aa engine which has a lower rated altitude and better climb rates and speed at low altitude, for a reduced top speed and climb rates at higher altitude.

What all four Emil models have is the same engine with a slightly higher rated altitude for the E-7/Z presumably to facilitate GM-1 activation at 6.5km. Performance in the E-4/B, notably climb rate is reduced to reflect a heavier take off weight (increased armouring).

Some engine modelling software like Engine Analyzer Pro can clearly show the transformation of the DB-601A-1 to the DB-601Aa through the fitment of a smaller diameter compressor casing (same impeller size), which reduces rated altitude for the benefit of higher outputs at low altitude. There should be far more clear performance differences than are modelled for the Emils.

The listed max.emergency outputs (official documentation) of the 601A-1 are 1100PS (2400rpm) at sea level and 1020PS (2400rpm) at 4500m. It can only be held for a maximum of one minute before a cool down. Normal maximum outputs are 990PS (2400rpm) at sea level and 960PS (2400rpm) at 5000m.

For the 601Aa they are 1175PS (2500rpm) at sea level and 1100PS (2400rpm) at 3700m. Normal maximums are 1045PS (2400rpm) at sea level and 1050PS (2400rpm) at 4100m. As mentioned the smaller supercharger casing meant you ran out of puff lower, even though the same internal size gives the same manifold pressures through the flight envelope.

The DB-601N engine was a tremendous improvement, involving cylinder head and camshaft profile revision in order to increase operating rpm from 2400-2500 to 2600 max. emergency rating. Whilst this would normally increase manifold pressure beyond engine tolerances, the effect of increasing the intake camshaft duration in fact reduced manifold pressure although the net gain is still increased power outputs. This engine was limited to using C2 or C3 high octane fuel, because it runs hotter than a 601A.

Outputs for the 601N are listed as 1175PS (2600rpm) at sea level and 1175PS (2600rpm) at 4900m. This max.emergency rating is believed to be historically increased for a five minute use before cool down. The normal maximums are 1020PS (2400rpm) at sea level and 1050PS (2400rpm) at 4850m.

One particularly annoying part of the E-7/Z model which definitely uses the 601N is that its operating engine speed is not increased at max.emergency/take off power to reflect the change from the 601A. This is not historical, although for the E-7/B it might be argued that many E-7 airframes were simply modified E-4/B types with the 601A engine, which is historical (similarly many E-4 aircraft were fitted with 601Aa engines and a some were fitted with 601N engines and left otherwise unchanged). The point is the E-7/Z model describes the Luftwaffe Me-109E/N(GM-1) aircraft, which most assuredly uses the 601N, of which all produced without exception, have a 2600rpm maximum take off and emergency setting.

An important point is that the 601N received a new supercharger when fitted to the 109F series airframe, which restored some of its lost manifold pressure and increased maximum output to 1200PS for take off.

According to another documented source these maximum emergency restrictions were removed during 1941, so that any 601 could use maximum emergency ratings until overheating occured. There was no longer a one minute or five minute maximum use restriction.

The later 601E of the Friedrich returned to B4 fuel use, but refined the modifications of the 601N "hotrod" engine to produce even more power. But that doesn't immediately concern discussion of the Emils modelled in IL2. The other Messerschmitt 109's may possibly be improved with more modelling attention to fine engineering details, but they certainly don't cry out for it as much as the Emil models.

PLEASE OH GOD OLEG REMODEL THE PERFORMANCE OF THE EMILS.

I'd say that about covers my sentiments.
I'm an engine enthusiast, IL2 is accurate enough in every other respect for me, but I like flight sims for the realistic engine modelling.

Thank you for your time.

JG14_Josf
04-16-2008, 09:57 AM
Some engine modelling software like Engine Analyzer Pro can clearly show the transformation of the DB-601A-1 to the DB-601Aa through the fitment of a smaller diameter compressor casing (same impeller size), which reduces rated altitude for the benefit of higher outputs at low altitude. There should be far more clear performance differences than are modelled for the Emils.

Vanir,

Do you have data generated on the DB engines from that program?



This engine was limited to using C2 or C3 high octane fuel, because it runs hotter than a 601A.

That statement precludes all other factors as meaningless? I mean, it runs hot therefore the higher octane fuel is needed and for no other reason?


involving cylinder head and camshaft profile revision

Did the compression ratio change? Did the efficiency of the combustion change?



Outputs for the 601N are listed as 1175PS (2600rpm) at sea level and 1175PS (2600rpm) at 4900m. This max.emergency rating is believed to be historically increased for a five minute use before cool down. The normal maximums are 1020PS (2400rpm) at sea level and 1050PS (2400rpm) at 4850m.

Those performance gains were caused by the cylinder head, camshaft, fuel octane, and compressor changes?


The later 601E of the Friedrich returned to B4 fuel use, but refined the modifications of the 601N "hotrod" engine to produce even more power. But that doesn't immediately concern discussion of the Emils modelled in IL2. The other Messerschmitt 109's may possibly be improved with more modelling attention to fine engineering details, but they certainly don't cry out for it as much as the Emil models.

All game performance is relative, relative to history, relative to other planes. I don't know your experience with this game and so my comments now are speculative. I speculate that you may not have started using this game when it first came out. There have been many changes along the way and one of the most notable relative differences for the 109s has been the difference between the performance of the 109G2 and the 109G6 one is a fighter plane and the other one is a target. My speculation is to suggest that you many discover reason to wonder about the modeling of those two versions of 109 once you get around to using them in the game.

If you already have experience with those two versions of 109 in the game and your engine oriented curiosity isn't awakened by the stark differences in modeled performance between those two planes, then you can ignore my speculation.

I like to read the data about engines. Thanks.

vanir
04-18-2008, 03:00 AM
Hey Josf. Nice to finally get to the weekend. It's been a long week. How's you, mate?
Anyway, down to business.
I love engines, yes. I prefer specifications to descriptions most of the time, generally I can infer a lot more information this way, and secondly, I can imagine far more effectively.


Do you have data generated on the DB engines from that program?
No. What I did was use the a variety of prepackaged engine sets to model a series of modifications, I used this system to develop mods for a car engine I use to race. A friend of mine, who races open wheelers put me on to it. I can come up with detailed cam timing specifications, ignition curves, recommended octane...anything you can do with an engine this software will deal with and it returns very accurate performance projections to within about 2% voracity of actual track performance (torque curves, cylinder temperatures, volumetric efficiency and so on).

This is how I knew about the effects of altering camshaft profiles and headport flow-coefficients when using superchargers, in particular the mechanical compressors (i.e. using an impeller) as used in aero engines.


That statement precludes all other factors as meaningless? I mean, it runs hot therefore the higher octane fuel is needed and for no other reason?

Did the compression ratio change? Did the efficiency of the combustion change?


Fuel octane is a descriptor of engine operating temperatures (particularly intake temperature) and ignition curves. When you put more fuel in (such as with a higher operating speed) the engine pings more easily. You're supposed to either ****** the ignition (actually you should remap the curves) or use a higher octane fuel. ******ing the ignition from optimum of course reduces the engine's operating efficiency, so higher octane is preferred, along with increased cooling (meaning bulky new radiators, oil coolers, etc.). The impression a pilot would get is that the hotrod engine simply runs hotter, but has more output, it's how it was with my race engine driving around on the road.

The increased cooling came with the Friedrich series according to various sources.

Here's an interesting thing. The 601N would actually have a much higher amount of intake-compression at the supercharger than the 601A due to the higher emergency engine speeds, but the manifold pressure isn't significantly increased. This is because the pressure at the supercharger exhaust is then released again by the longer duration of the intake cam timing, during the cylinder-compression stroke (the intake in supercharged engines is compressed twice, once by the supercharger and a second time inside the cylinders, so it can get pretty hot in there).

Oh yeah: greater cam timing duration lowers dynamic cylinder compression. Static compression ratio however remains the same. Part of the head revision would have been to increase static compression to around 9:1, which reduces to 8.5/8.3 intake/exhaust dynamic compression, or good enough for 96 octane (C2/C3). The reason this is done is in an attempt to compensate for the loss of dynamic compression by the longer valve timing.

Lastly yes these things alter engine efficiency. Increaseing your cam timing reduces it. Volumetric efficiency was probably around 135% for the 601A whereas this was probably reduced to 130% for the 601N. So fuel economy goes down.

What you really need to do to bring the efficiency back up is put a larger volume supercharger on, which is what was done in the Freidrich. Hence the Freidrich has a longer range with the same fuel capacity, which is also helped by its improved streamlining. The Freidrich also runs cooler with the 601N due to bigger radiators and oil cooling. This probably has something to do with the development of the 601E engine and the switch back to B4 fuel.



In il2 I've flown the Emil more than later models, though of course I've flown them all. As a simmer I'm still in the learning stage so have assigned myself training duties in an old Emil.
I like the way the F-4 flies best of all. The G-2 and G-6 seem pretty accurate from 4.05 and 4.09b which is what I've prolly done most of my flying with. Not all that much to tell the truth but enough. I mostly use il2 to make semi-historical screenshots which I use for book illustrations. I'm currently writing 1 novel and 1 non-fiction and will hopefully get Ubisoft/1c/Oleg Maddox' permission to use the screenshots in commercial publication.

I mean you could fine tune up the G-6. The G-6/AS could use a little better acceleration at normal engine operation (without boost) as it is a little slipperier through the air. The handling of the Gustavs should be mostly affected when carrying stores really. The issue with flying them clean is torque effect and acceleration. Climb and dive rates are still good, barely affected by even external stores in fact. Most of Erich Hartmann's 352 victories were in the G-6, flying against things like Yaks, Lavochkins and Mustangs no less.

The K-4 too, could use some fine tuning. It never used a DB engine (preproduction only), that was passed onto the G-10. In 1944 it used the DC engine and in 45 some got the ASC engine, both running on C3 fuel. The only difference between those two engines is cruise performance, maximum outputs are identical in every respect (even though the ASC has the supercharger from the massive 603 motor). The ASC basically has a better range on the same fuel tankage, especially with stores. It also cruises at a much higher altitude, so much faster too (but only in cruise).

Everything else is pretty good for the 109. You use the G-6/AS to substitute the G-14/AS, which was mostly converted G-6 airframes anyway. And Bob's your uncle.

JG14_Josf
04-18-2008, 07:02 AM
What you really need to do to bring the efficiency back up is put a larger volume supercharger on, which is what was done in the Freidrich. Hence the Freidrich has a longer range with the same fuel capacity, which is also helped by its improved streamlining. The Freidrich also runs cooler with the 601N due to bigger radiators and oil cooling. This probably has something to do with the development of the 601E engine and the switch back to B4 fuel.


Vanir,

I read that far and stopped for a question and comment or two before continuing my reading of your fascinating reply.

Increasing power is the bottom line and, as the saying goes, there are more ways to skin a cat. I'm reading many of the historical changes being made, and yet remaining somewhat skeptical when data is not available to illustrate these changes being done with documentation, and it occurs to me to ask for opinions as to why somethings were done while other things were not done during the process of gaining power.

Why use a hydraulic coupling to drive the impeller for the compressor? The DB engine, as far as I know, was the only one to have incorporated the hydraulic coupling while all the other engines used one or two gear sets to directly drive the compressor.

I think the choice to go with the hydraulic coupling ended up with a flattening out of the power output at altitudes under the peak altitude. In a case, for example, where the same DB engine fitted with a two speed direct drive supercharger (compressor) the plane would have two peak power altitudes compared to having only one peak power altitude for the DB engine fitted with a hydraulic coupling.

The DB engine with the hydraulic coupling would not peak at the lower altitude, yet it would not suffer either at the altitude just above the lower gear ratio peak altitude.

With that type of question in mind I wonder if a power output notation can be added to these types of discussions.

Example:


Fuel octane is a descriptor of engine operating temperatures (particularly intake temperature) and ignition curves.

In other words (and if I have this right) Fuel octane does not increase power. Higher octane does not (and could actually reduce) increase power. I've read that from a few links that you may enjoy reading.

Here:

RON (http://www.madabout-kitcars.com/kitcar/kb.php?aid=124)


It might seem odd that fuels with higher octane ratings burn less easily, yet are popularly thought of as more powerful. Using a fuel with a higher octane lets an engine be run at a higher compression ratio without having problems with knock. Compression is directly related to power, so engines that require higher octane usually deliver more power. Some high-performance engines are designed to operate with a compression ratio associated with high octane numbers, and thus demand high-octane gasoline. It should be noted that the power output of an engine also depends on the energy content of its fuel, which bears no simple relationship to the octane rating. Some people believe that adding a higher octane fuel to their engine will increase its performance or lessen its fuel consumption; this is false - engines perform best when using fuel with the octane rating they were designed for.


And here:

Axis avgas (http://www.fischer-tropsch.org/primary_documents/gvt_reports/USNAVY/tech_rpt_145_45/rpt_145_45_sec2.htm#Engine%20Testing)


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.)

When I read things like this:


Oh yeah: greater cam timing duration lowers dynamic cylinder compression. Static compression ratio however remains the same. Part of the head revision would have been to increase static compression to around 9:1, which reduces to 8.5/8.3 intake/exhaust dynamic compression, or good enough for 96 octane (C2/C3). The reason this is done is in an attempt to compensate for the loss of dynamic compression by the longer valve timing.

I read about the reasons for making changes and I am inclined to stress a need to be skeptical. The main reason for engine improvement is to gain power – no?

Why not add a second spark plug to reduce knock?

I'm just throwing out a question just because it is interesting to me.

I'll continue to read your reply and comment again. I do like reading these types of posts.


I'm currently writing 1 novel and 1 non-fiction and will hopefully get Ubisoft/1c/Oleg Maddox' permission to use the screenshots in commercial publication.


That is very interesting. I've thought about doing the same thing and just recently I've taken a class in writing. If you could use a collaborator, a critical editor, I am offering my viewpoint.

Here is an example of my work (from an After Action Report describing an IL2 squad oriented on-line war called Forgotten Skies):


The flight surgeon was distracted by Gretchen, as no one else can, while Leutnant Kinsfelt removed the required document from the file cabinet. Leaving nothing to chance, or irrelevant opinion, the impending mission was attended. The duty officer took a look at the flight order then the cast and shook his head as he stamped the order and gave it back to Joseph.

In the operations room Joseph's new wingman stuck his foot out in the path of Joseph's crutch sending the man into a hopping frenzy to regain balance. Both recruits then squared off like a couple of roosters preparing to see who is in charge of the hens. It was as comical as could be tolerated by the Schwarm leader for a second and then both men were abruptly placed in their seats. Fun was fun but this was the pre-mission briefing.

The idea of driving all over enemy territory clipping tree tops like underpaid landscapers did not appeal to Joseph, however the new wingman, an old hand at this with two missions already under his belt, encouraged Joseph to see the fun in it.

"They can't see us. Just follow me and you will be fine." Joseph remained skeptical all the way out to the flight line.

The crew chief knew better than to help as Joseph hopped from the rudder where he left the crutches and left the morning's coffee pooled in its new yellow form around the tail wheel. The tire looked flat and it occurred to Joseph to avoid aiming for it next time.

"Look at the poor Leutnant hopping for pity. Forget it, stupid. You are on your own." Hector, the black man, folded his arms and watched as Joseph paused at the wing root with one hand stuck in the spring loaded recess behind the cockpit canopy. The cast foot on the right would not fit into the foot hold.

"Alright, Hector, I need your help; please. Just get me over the cooling flaps. I can swing in once my *** is on the sill." Hector called over to another Blackman for a stool.

"Try to bring this one back heir Leutnant. We have more but I'd like to get one in character. You know what I mean?"

"Ja, Hector, of course and you know I love to have these things blow up around me. If I bring back a scalp will that bring my credit back into the black heir Hauptwachtmieister?"

"Will you deliver this scalp by train, by car, or as you land this plane of mine right back here? I just want the plane back, please, and preferably in the same shape that it is in right now if not better; take it easy at first since the engine is not yet set. Don't let it get hot. We ran it up for an hour last night but not with the right load. You can help. We can make this plane a good one." Hector was yelling by the time Joseph sat.

Looking down from his perch on the cockpit sill; Joseph paused and then looked up and around at the other fighter planes starting, props billowing dust, as the Staffel prepared to take-off.

"Hector my friend." Joseph spoke above the engine and prop noises assaulting from all angles. The Russian spring generated a cold breeze from the west that sent a chill down into Joseph's throbbing ankle.

"It looks like a good day to break a leg."

"Ja mein Leutnant, it is."

http://4jg53.org/gallery/albums/userpics/FSmis1num2.jpg

The picture is taken from a track file made during the mission. After I wrote the AAR I realized my words described a 109 when the plane I flew in the mission was a 190D-9. Rather than correct the error I left it since the idea was to create a war time atmosphere rather than be accurate about mechanical details. Some of the guys in our squad will undoubtedly notice the error and perhaps spoil the mood.

I am serious about the collaboration on the book and I know how business works with many people so you may want to protect your work from me, a potential competitor, who could be out to steal your ideas. My ability to make money with writing is the object of the course I am taking. There is a network, like most professions, and the price of admission, for me at least, is this expensive course. So far I have many complaints about the course, yet it does already show much value in the ˜connections'. For example I have a book now that lists all the published magazines that seek submissions from freelance writers. The book is very large.


The issue with flying them clean is torque effect and acceleration. Climb and dive rates are still good, barely affected by even external stores in fact. Most of Erich Hartmann's 352 victories were in the G-6, flying against things like Yaks, Lavochkins and Mustangs no less.


Do you understand the nature of physical drag loading? I mean specifically the later part in the following formula T/W – D/W?

Here is a clue:

Drag race (http://www.fourthfightergroup.com/eagles/109gtac.html)


Dive
19.........Comparitive dives between the two aircraft have shown that the Me.109 can leave the Spitfire without any difficulty.


And Bob's your uncle.

He died in a motor cycle accident before I was born.

vanir
04-18-2008, 10:16 PM
Why use a hydraulic coupling to drive the impeller for the compressor? The DB engine, as far as I know, was the only one to have incorporated the hydraulic coupling while all the other engines used one or two gear sets to directly drive the compressor.


Each gear has its own rated altitude and the next one can't be engaged until well above the rated altitude of the last one. You have to exceed the rated altitude at medium altitude where some combat occurs and your climb rate drops markedly. The Daimler-Benz doesn't have this issue, it was a pretty ingenious design. Companies developed new ideas in engineering motors for high performance during these years, US companies didn't want to release turbosupercharger designs to foreign air forces equipping their exports. Even German engineers had problems developing turbosuperchargers and gave up on them.

The fluid drive coupling is a single supercharger gear, but slippage related to hydraulic pressure at lower altitude gives the effect of a constantly changing compressor speed, tuned to engine requirements. This works in conjunction with the aeromechanical screw and mechanical fuel injection to provide a very low pilot workload and sterling performance. Time to altitude are the Gustav's best figures, with around 6min to 6000m. It's a good couple of seconds ahead of the pack. Plus the rated altitude at 5.8km means there's no performance drop offs or flat spots from take off to bomber interception, the average combat height in western Europe was said to be 5km.

A 1944 RAF comparison between the G-2 and Tempest V gave it a better climb and almost equivalent manoeuvrability, though the Tempest was of course much faster especially at low altitudes and in extended dives. This competitive nature some two years following service introduction was due to the hyrdraulic supercharger.

The supercharger does have a drawback in that it heats up oil at lower altitudes, so the 605 motor runs hot and likes to overheat at low altitude.


Why not add a second spark plug to reduce knock?

Engine knock is caused by pre-ignition, i.e. the mixture is being ignited whilst the piston is still in the compression stroke, hence it can break things. Putting more spark plugs in won't help much.
You can get engine knock by increasing manifold pressure in supercharged engines, increasing cylinder temperatures and increasing intake temperatures (which tends to go hand in hand with increased pressure). When you raise your octane it also burns less effectively and dual spark plugs would probably help then, along with a well designed combustion chamber. Daimler's approach to this was by keeping manifold pressures down and raising output with displacement and rpm, taking a hit in ignition timing if need be. The 605A-1, AS and D engines all use B4 fuel and put out from 1435 to 1550PS for take off (although climb and cruise outputs at altitude are the real measure of the 605 engine).

The big drawback of the 605 series is the MW-50 fitments early in 1944, the 605A/AS were just not built for the dramatic increase of stresses. The 605D was at least built for output development and coped with increases to as much as 2000PS for take off admirably, as did the 1945 series of the AS engine (in B4 and C3 variations, both with MW-50).
At this time, a good example of a current 605 engine was perfectly contemporary with anything in the Allied arsenal, but the series had an obsolete period during 1944, which is well documented by British comparative testing. It seems to me the reputation of the Me-109 was regained only by the K-series, but as many have said some examples of the G-14 and G-10 could be a damn tough fight for any Allied pilot in 1945 too.

19.........Comparitive dives between the two aircraft have shown that the Me.109 can leave the Spitfire without any difficulty.


Don't forget the +25lbs rating for the Mark IX is for 150 octane fuel too, and was adopted by some squadrons in the later half of 1944 and 1945. The Gustav compares reasonably well with the Mark IX Spitfire at 18lbs. According to German ace vets the only manoeuvre they couldn't follow a Spitfire in was a turning climb.


Here's a pic of an early scene in the novel, where our hero arrives in Rumania to join his fighter conversion squadron (Erg.Gr./JG 52) just prior to the invasion of the USSR.
http://img216.imageshack.us/img216/2415/rumania013xn4.jpg

stalkervision
04-19-2008, 10:15 AM
Vaniar, thanks for all the excellent info on one of my favorite subjects,the M/B 601N! http://forums.ubi.com/images/smilies/11.gif

now did your grandma ever tell you about hearing about luftwaffe plywood or pressed paper tanks on the real early e model me-109 that leaked..? http://forums.ubi.com/images/smilies/winky.gif

well I gave it a shot.. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Kurfurst__
04-26-2008, 04:01 PM
DB 605DB and DB 605DC are in fact the SAME engine, just in a different fuel configuration - the B is probably standing for B-4 fuel while the 'C' is for C-3 fuel. DBs could be converted to DCs and DCs into DBs with relative ease as I understand it.

The ASB and ASC are some sorts of equivalent to them, probably old A-series engines converted to higher boost. It`s a bit a grey zone as far as little details go, though for practical purposes (output etc.) they are the same thing. Prien and some others note the ASC was fitted to G-14/AS.

Both the 109G-10 and 109K-4 could be fitted with either configuration of the SAME DB/DC engine, though the maximum output of 2000PS at 1.98ata manifold pressure was limited to the DC configuration. And, photographic evidence of G-10 in the WNr 612xxx-613xxx range shows that a lot of G-10s were very likely to have configured to DC - they are marked with the C-3 fuel triangle, which points to the DC engine.

Unfortunately over the time with all that hiss over the 109K-4/C3 variant people started to think only the 109K version had the 2000 PS option. This is not true, the G-10 was powered by the same engine, and had the same power options (1800/1850 PS on 1.8ata, and 2000 PS on 1.98ata), depending on fuel.

The G-10 is best thought as a sort of hybrid, a Gustav airframe with many 109K internal system. It spared time for airframe manufacturers who thus didn`t need to switch to 109K airframes, but could use to same parts like engines, generators etc.


As far as the Emil series go, it sees complicated.

The base E-1, E-3, E-4 uses the DB 601A-1 engine. To make it even more complicated, the DB 601A-1 appears to have used an early and a later type of improved supercharger, with 4.0 km and 4.5 km rated altitude...

The Jabo-modified series with the /B suffix are dealt here as a different type. E-1/B, E-3/B and E-4/B variants appear to have been fitted in each and every case with the slightly more powerful DB 601Aa, probably to offset the extra load on the aircraft.

The E-7, which could carry a droptank or a bomb, probably due to similiar considerations, also used the DB 601Aa, so far every E-7 found had it... it appears to be standard.

Then there are the /N variants, again dealt as a subtype of its own right. The /N suffix simply meant that the subtype was fitted with the DB 601N - the one fitted into the Emil had lower rated altitude than the 109F, mind you!. This engine that got into production in late 1939 had considerably increased output at all altitudes, and run on 100 octane fuel.
Officially only E-4/N and E-7/N existed (produced in factories), but evidently from strenght reports the shops converted E-1s and E-3s as well. The exact amount is hard to tell because of this..

Then there`s the E-7/Z which is basically an E-7/N with the DB 601N, plus fitted with GM-1 boost.

vanir
04-30-2008, 06:25 PM
Thankyou so very much for your post Kurfurst, it has been extremely difficult to figure out specifics about the Daimler engines and I've had to use every method available, including simply modelling various layouts with auto-engine software and making assumptions!

You've cleared things up for me beautifully and I am in your debt. Cheers.

(edit) If I might make a suggestion about the ASB/C engine that these would be the DB/C engine but simply fitted with the DB-603 supercharger (as denoted by the AS designation). This would mean they inherit the B-4 or C-3 stipulation from the D-series, but use the supercharger of the AS engine. It seems a logical possibility to me.

What I find interesting is the altitude rating between the ASB/C and DB/C engines are virtually the same, with only cruise outputs changed between them. I would think actually the ASC is the better of all the D-series.