109 e3b against spitfire II
 

hey guys!i was just playing on a server where most of the guys flew the spit II.
normally i had no problem to fight against spits online.but it seems that i havent faced the spit II online yet.im pretty clueless how to fight this oponent.
its seems to climb faster and turns faster and tighter anyway.the only manouver that worked was to dive, but ending up at low altitude is a bad situation.so i tried to gain some altitude, but as soon i climbed,the spits were back on my near six.is there a way to be the hunter and not the bait online with the 109e3b against the spitII or do you have to hunt in hordes??
im mean i know the importance of altitude adavantage, but on the small dogfight maps, i couldnt gain it before i was already chased.

U cant. SpitII simply better. It was in RL too (The messer can climb higher, but its dont work in game now). E3 -in this configuration- is spanish civil war era (early '39 - LW get the first planes there), Spit II the BOB most advanced RAF type (Aug. '40). Untill LW cant get E-4, E-7, .../N planes, the SpitII banned in most (historical) servers.

Fly with E-3. Difference with E-3/B only the bomb rack, it makes the plane slower.

edit. Ahh, and one more thing :) The E-3, E-3/B manual Prop pitch is much slower, than should be, big disadvantage anyway with this. We hope, it will be fixed in next patch.

That´s quite accurate if we want speak always about realism. And that must be also, with very little difference, the same for the Mk.I. Always in theme realism, the E-1 MG only armed must also be present. A good number of this version were still operative by Aug 1940.

Get a wingman. It is the best thing you can do against Spit2 :)

The 109E3 was not a Spanish civil war variant, the 109B was. Also the just like the Mk I Hurricane and Mk I Spitifres, the 109E went through various changes from the early 1939 variant at the start of the war to the versions that saw action in August 1940 over Britain.

More powerfull engines were introduced during the production run which kept the 109E competitive with even the Mk II Spitfire. What the problem is with Cliffs of Dover is that the Spitfire Mk IIa matches the performance of the real +12lbs boost Mk II while the 109E comes nowhere near its historical 1939 figures let alone its 1940 figures.

The Hurricane Mk I Rotol is also getting speeds that match a real +6lbs boost version instead of +12lbs boost, so it is also too slow for a BoB era Hurricane. The Spitfire Mk I, Mk Ia and Hurricane DH are massively underperforming and don't get close to real figures for +6lbs versions let alone +12lbs boost versions. Then we have the Bf110 which matches the performance of a DB601-A variant, the problem is that around 50% of the Bf110s in the battle had DB601-N engines which ran on 100 octane fuel giving them a large performance boost.

What we have are some woefully underperforming fighters that don't match any published figures and seem to use generally made up performance based on nothing in particular.

Spitfire Mk Ia (Rotol)
Spitfire Mk I (DH)
Bf109E3
Fiat G.50
Hurricane Mk I (DH)

We have a total lack of any +12lbs boost Spitfire Mk Is or Hurricane Mk Is that would have been the most common variants at front line squadrons. We also have a total lack of the DB601-N equipped Bf110.

Online servers have a serious issue. Allow the Spitfire Mk IIa, which is the ONLY RAF aircraft with close to real life performance. The problem being that it totally dominates the woefully underperforming 109E and Fiat G.50s. Or ban the Spitfire Mk IIa and watch the domination swing way in fovour for the 109E because the Spitfire and Hurricane Mk Is have performance that is even further from reality than that of the CoD 109E.

A lot of work is required on the majority of FMs and aircraft performance.

Im totally agree, FM necessary to fix, on both sides.

E-3 was not the main fighter, but in spanish civil war, "early in the year (1939) J/88 had recieved 40 new cannon-armed Bf 109 E fighters, and the outdated early marks were passed to Gruppo 5-G-5. On 5 March Mölders's replacement as leader of 3 Staffel." (Osprey Airwar3 - Christopher Shores: Spanish Civil War Air Forces, page 42)"

In this configuration: MG-FF cannon, non automatic cooling system, non automatic Prop pitch system, basic DB601 engine, this is spanish civ war variation. Couple of these aircrafts using in BOB (much less than E-1, E-4, i dont know, why chosen this airplane), but this does not make changes in it, that this machine of what date, and that the LW was much more advanced type under the BOB period.

Im totally understand the virtual RAF pilots situation, 100 octane fuel, +12lbs boost is missing, but LW missing whole series, not just components :rolleyes: Untill LW cant get "BOB era" planes, the (historical) mission makers have no other opportunity, have to create Battle of France maps.

ICDP: A short number of E-1 and maybe some experimental E-3 were used by the Legion Condor in the last stages of the war. The I-16 sometimes was more of a match for the early 109 versions.

I am aware of this, I was responding to VO101_Tom's post on the 109E3 in the Spanish Civil war. Upon re-reading his post I now realise that he meant the current CoD 109E3 is actually performing closer to the very early 109E3 as it was configured in early 1939 (i.e. pre-war). If this was his point then I agree, though the 109E and early Mk I Spitfires and Hurricanes are actually performing slower than they should even for this period.

Honestly, dude. Who do you think is gonna fly it online? Who's gonna make a mission guaranteed to make half the flyers say: "See ya later!" Might as well make a mission where red has only the Tiger Moth to fly.

Why not? Especially when MGs with incendiary ammo are so effective in CoD.

Surely there has to be some limit to the amount of incendiary/tracer you can load? Eh, what am I thinking about. Sense?

There's also the argument to be made for the eventual completeness of the plane set.

Being able to do proper Spanish Civil war scenarios, for example.

That would take a lot of planes. Would be cool, though. Cr-42, I-15, He-51...what other kind of stuff could we learn to argue FM's about? LOL

Yep...lotta work there...even if you were only covering the early monoplanes.

Very nice post ICDP,

Just on that sentence
I think we are very far from the Bf109 having an advantage to their favour.

Most fly "crappy" (I beg for forgiveness for this comment). Bf pilots can not Boom & Zoom which is the only thing the Bf109 was good at, because of three deadly parameters:
#1: No usable propeller pitch: congrats to the guys which made it "historically correct" and screwed up probably 99% percent of Bf pilots to that day. May God (ehem Oleg...) punish them by letting them stick to this Bf flight model for the next five years! :(
I admit I am subjective here, please read under 99 percent just myself, I stopped flying Bf and flying Spits, so it is a strictly private opinion/ it is mine and I will have to live with it (and I can, by not flying Bf109 any more).

2. Head movement restriction in gunsight mode makes a Bf109 pilot not been able to track the opponent while manouvering verticaly and aim for deflection shots at the same time ("lose sight, lose fight").
I spend seven years of my life flying Bf109 exclusively in IL2FB only to find myself unable to dogfight and shoot in a Bf109 in CoD :(
May God punish Luthier by having him dogfight non-stop in Bf109 gunsight mode for the next five years... ;)

3. To add insult to injury(point #2): Poor graphics performance and smaller airplane size (maybe it is my subjective opinion) make difficult to recognise and track and airplane with the ground as background. Since the only way for the Bf109 to win a fight is on the vertical, it is much more difficult to track the enemy in CoD than in IL2FB.
My heart is full of condolence when I see these poor SODs in their Bf online, losing sight of me and by the time they have regained situational awareness my Spit is already behind them, and then game over. I can not even feel proud of shooting down Bf109s nowadays :(


Just my 2cts, I am sorry if I sound bitter, I am honestly not, I am more sarcastic than serious, now that I jumped the fence (and switched to Spit) my problem is solved and I enjoy the game. And hope for the best...with the patch, in three days ;)

~S~

resume of above edit :

Q: Why the 109 is useless against Spit II
A(s):
a/It's historical fact
b/we got crappy FM and the Spit hve to get the 12lbthat & that thing (that I miiss from IL2 )
c/ (added certainly to makes good figure) Oh ..; by the way the Hurri shld also get the 12lb eng

and so on and so on ...

C'mon guys : there was no 12lb Spits - there was AN EMERGENCY SWITCH in SOME of the plane based in england !
The Merlin XX did get 9lb boost and it was an after BoB engine
The FM of the Spits is simply surrealistic even for the MkI
This is not the number (perf achieved ) it's in the way it can turn and climb (E grabber) - TAKE TIME to fly in ALL the planes we hve for now: IT'S SO OBVIOUS !

So pls be constructive not selfish and don't touch the superb FM we hve for now for both the Hurri and the 109 to fit your own expectation.

Those men were brave. There were not in anyway counting on any X-men to fight for their freedom.

Then don't use gunsight mode.

Yes, it was. Partially. :)

E-3 enters in service early '39 in Spain. If this would not be enough, ingame performance less than should be (especially in high altitude), bacause of weak modelled engine. Early Spit and Hurri have same problem, but its irrelevant to E-3b vs Spit II question, bacause Spit IIa has no problem like this. :rolleyes:

The other thing, we miss what the German engineers developed until one and a half years (at least till aug '40, when Spit II enters service, but its far from end of BOB). Nothing important, only new engines, 100 octane fuel, MG-FF/M gun with mine effect ammo, automatic cooling and PP system. Luthier promised it already, that if not all of them, but we receive some things of these... (We hope, not in Battle of Moscow dvd http://www.pumaszallas.hu/forum/imag...es/tok-tok.gif :grin:)

I am actually a Spit flyer....
By all those comments i jumped into the Bf109 to ckeck it myself....
FFS...i can understand each pilot "whining" due a Bf109 in CloD.
It feels like the hurricane Mk1 in Il2FB.
Totally unstable in slow flight, turning like a Bf109G10 in Il2FB.
The revi is almost useless in hectic dogfights.

All your comments above are much more detailed for sure.
Nevertheless i can understand, if just a few pilots are fancy flying a Bf109 on servers, coz it feels like XXXX
Hopefully sth gets changed in the next patch in the Bf109FM, as i am not interested to fly a 5:1 (red:blue) on servers.

I presume you fly Bf109 all the time without gunsight mode so, I respect your experience (and hope there is more Bf109 pilots which share the same point of view).

Unfortunately, my LCD screen is too precious and I will not stick a chewing gum in the centre to compensate for the REVI... comedian! :(

With TrackIR, i can fly without gunsight mode (i have to...). Anyway i fly with 90 FOV in dogfight, all time. But took time while I got used to it :rolleyes:
I dont know how can dogfighting anyone withouth trackir, or freetrack...

do not be flying low!
if you are flying low, do not turn!
if you turn low, do not turn slowly!
if you turn low, slowly, do not be surprised!
;)

Are you crazy? Did you count how many years (in old IL-2) till the Spits FM was adjusted? It had to be an external team (TD) to do it, cause MG, over the years, were only interested in porking 109's. :-P

Beware TomcatVIP, what your saying is going to be taboo even in a late stage of development of this simulation... :rolleyes:

Yes, all the time. Zero experience required - just center the Revi. :)

He, he, so you do centre the Revi after all.... ;)

and fly outside gunsight mode with the Revi centered.

And all the other poor sods without 6DOF will get stuck in their fate :(




PS. or can I do that without 6DOF as well?

Pretty much all Spitfires & Hurricanes were running on 100 octane fuel with +12 psi war emergency power available during the battle. This is extensively documented.

All Spitfires and Hurricanes had boost control cutouts until later in the war when gated thottles began to appear.

You can get into an argument about how much boost was developed by operating the cutout; but at sea level it was never less than +12 (early Merlins prior to the +12 mods would actually deliver about +17 with the cutout operated, much to the detriment of the engine given that prior to +12 mods they were running on 87 octane).

Very few Merlin XXs took part in the Battle of Britain.

It's possible that they might only have been cleared to +9 in FS gear in the very early days. I haven't investigated this because I've never been especially interested in the early production Hurricane II; it's perhaps analogous to getting deeply involved in the performance of the Bf-109F0 in the same time period.

However, it seems extremely unlikely that the Merlin XX would not have been cleared to at least a +12 combat rating in MS gear at entry into service because in MS gear it's turning the 10.25" supercharger at 8.1516 times crankshaft rpm. This is lower than the Merlin III (8.588 ) or XII (9.089) and would therefore produce a lower charge temperature.

The Merlin in Perspective credits the XX with a +14 combat rating in MS gear and a +16 rating in FS gear, with the takeoff boost being +12.

So really you don't have much of a leg to stand on unless you want to take the view that 100 octane fuel was some kind of collective hallucination by everybody involved...

The most likely explanation for the +9 rating is either a typographical error, or simply the use of a non-combat rating for whatever test you've got that figure from.

This, of course, is a debate about reality. Matters are complicated by the fact that, at least at present, the sim has quite a strange FM which seems to have some important problems, not least of which is erroneous engine indications for all the Spitfires & Hurricanes.

The Spitfire II, when last I tested it, has optimistic +12 performance but questionable full throttle heights and incorrect boost indications, and therefore almost certainly other problems.

The Spitfire I seems to have some kind of hybrid 87 octane performance, but again I'm not really sure what's going on because the boost indications are actually wrong for that as well.

At the moment, I don't think you can really say that the Spitfire is too good or too bad, because the testing that I've done suggests that it's just plane wrong in a sufficiently large number of particulars that it's almost pointless to get into that kind of debate.

In any case, it takes two to tango, and although I'm no expert on the 109, I have absolutely no reason to believe that it's been modelled perfectly either.

I think that the solution is to wait until the sim stabilises a bit, perhaps after the US release, and then set about a rigorous test programme to actually get to the bottom of what's going on.

Of course, even if we get kinematic performance of all the aeroplanes to closely match test data, that's just the start; we've also got to deal with the reliability and cooling difficulties associated with running at high power, because otherwise everybody will be screaming along in war emergency power the whole time, which might well have "balance" implications, in as much as some aeroplanes would probably gain more from this unrealistic performance capability than others...

If I recall correctly: middle mouse button + right mouse button gives you additional 2 DOF. Move head to right and leave it there. Should work with panning, but I am not sure about snap views.

ViP

1. I am referring to the XX as it top off the III perf. . The XX is a well known referenced eng with plenty of raw data available and introduced latter in the war as an improved eng. Draw your own conclusion but I doubt pilot will have been happy to see their eng changed for the "less powerful" XX when they were asked to fly across the channel to bring the fight to the enmy.

So as you say that "very few XX took part in BoB" you are right on what I am pointing out

2. we hve started from a 6.5lb with an emergency boost of 12lb on a 87 oct and we were discussing abt a 100oct at 12lb vs what I think is a Merlin 100oct topped a 9 (my Merlin argumentation based on the RR sources you know pretty well and based on Qualorific assumption (the amount of heat generated).
Now if I read you well we shld hve a 17lb 100oct ? Humm will I hev to fear reading in the upcoming weeks about the Jet eng being available during BoB (see spitperf.com and blablabla) ? ;)

3. You are mixing your argumentation with a lot of data that many young reader can't understand and that hve no meaning here. Just let make it clears MS gear refer to the charger's impeler de-multiplication (the speed at witch it turn related to the main crankshaft) that had to be kept bellow a certain speed for the efficiency of the overall boosting process. There is no link with the SHAP but only with the fighter speed and the alt of this perf. giving that the supercharger was designed for fighters on the base of procurement policy (by the way I read that the twin speed supercharger was patented by Farman and hev a hard time figuring in witch Farman's plane he wanted this installed :rolleyes:). Pls don't smoke the debate. Logic is at the reach of everyone (pls make the V hand sign reading this).

4.you alrdy stated about installed eng power that match only what I have here as an eng not fitted with a supercharger (the 1.3k+HP data) - maybe shld you look at your references.

By the way ~S! and thx to forgive me for my bad English grammar & spelling :oops:


@MC
Yeah I am sure am taking the risk being half read with only our poor 109 and hurri being stuck with what I feel looks like more realistic flight-model.

However I am sure that 1c won't hve so heavily worked the FM regarding Il2 if they didn't pay much interest in this. Hence I am full of expectation :grin:

Nice too read you here. lking frwd to see you in CoD's skies :)

Actually, this was discussed many times already. Sure there's extensive documentation of 100 octane use, which perfectly warrants that we have 100 octane variants of Spitfires & Hurricanes in the sim.

However, the claim that all of them were running on the fuel is quite simply baseless and there's no evidence of this, and it can be considered a bit wishful. On the contrary, there's convincing evidence found in archives detailed fuel use and decisions that the proccess of conversion begun in the spring of 1940 only (preceeded by various trials), and much of the force was still flying on 87 octane and lower engine power during the battle, until toward the end of 1940.

Post of the year IMHO. Thx ! :-P

Once again Kurfurst continues his proud tradition of providing one sided disinformation, with no facts to back up his case.

This issue has been gone over many times and on many boards, it has been written about, published etc.

And the conclusions are clear. RAF Fighter Command had 100 octane fuel in plentiful supply at all of its major 10, 11, and 12 Group fields. (and these fields provided the supply for their satellite fields)

The best debate on this issue occurred on the WWII Aircraft forum which has very high standards of proof required. The discussion was led by 'Glider', real name Gavin Bailey, who is published on the subject of high octane fuel use by the Allies in WWII. His article "The Narrow Margin of Criticality: The Question of the Supply of 100-Octane Fuel in the Battle of Britain" was published by THE ENGLISH HISTORICAL REVIEW, a well respected historical journal whose material is subject to critical scrutiny by the best of English historians.

Article here:

http://ehr.oxfordjournals.org/conten...1/394.abstract

The debate on the WWII Aircraft forum can be found in two threads. If you are seriously interested in understanding the facts, then take the time to read both threads in their entirety.

http://www.ww2aircraft.net/forum/avi...2-a-20108.html

http://www.ww2aircraft.net/forum/tec...bob-16305.html

Kurfurst was present there, and added his usual disinformation, refused to provide references and was banned from the forum.

For Kurfurst to continue to put forward his disinformation here, despite all the other occasions where that disinformation has been discredited is just another example of his lack of objectivity.

For CLIFFS OF DOVER to have an accurate set of aircraft models, it should have the following:

Hurricane I (two speed prop, +6 boost 87 octane)
Hurricane I (two speed prop, +12 boost 100 octane)

Hurricane I (constant speed prop, +12 boost)

Spitfire I (two speed prop, +6 boost 87 octane)
Spitfire IA (constant speed prop, +12 boost 100 octane)

Spitfire IIA (constant speed prop, +12 boost 100 octane)

It is not good enough to have only a Spitfire II with +12 boost performance. Historically Spitfire IIA's only equipped 3 Squadrons during the battle, most Spitfires were the I model, running +12 boost.

Hurricanes must have a +12 boost version, including the two speed prop version, since Hurricanes were converted later than the Spitfires to constant speed, and there were quite a number of two speed prop versions in use in July and August running +12 boost.

The +6 boost versions of the Spitfire and Hurricane are required for 1939 and January to April 1940 scenarios.

Thanks, very good links, i noticed one thing, what was topic here, the "constant using 12lbs"topic...

"1st August 1940 Memo from Downing re the Handling of the Merlin Engine
This note is advising the pilots that there is an increase in engine failures in the overuse of the emergency 12lb boost.
The interesting thing is that this memo was sent to ALL fighter groups. Had we been talking about the 16 squadrons or less this would not have been the case. It would have been sent to the squadrons involved."

This clears up that question rather unambiguously. :rolleyes:

The Merlin XX was given official approval to use 12lb boost for combat in MS gear in Nov 1940, but the engine was cleared for 12lb boost/3000rpm for TO right from the beginning, and so was available to any pilot who cared to use it during combat.
http://www.wwiiaircraftperformance.o...s-10june40.jpg
http://www.wwiiaircraftperformance.o...xx-15nov40.jpg

Approval for 14 and then 16lb boost was added later, along with the appropriate boost override modifications.

Source please.

Source please. This was already discussed. http://forum.1cpublishing.eu/showpos...0&postcount=38

Based on the current evidence (feel free to add new sources showing 100 octane at the said airfield during the Battle and I'll update the list) shows that 100 octane aviation spirit was supplied to

8 out of 19 Sector Airfields
9 out of 32 Fighter Airfields (however 7 of the 32 functioning as satellite airfield for rotation etc., with no Sqn permanently based there).

Glider has nothing to do with Gavin Bailey, nor anyone participating in the thread for the matter.

As for Bailey's article, it doesn't state anywhere that 100 octane was universal for fighter use; actually, it gives little attention to subject of the extent of use, and instead it concentrates on belittlening the - allegedly widely and wrongly perceived - importance of American 100 octane imports, and the put emphasis of CSP propellerers.

On the matter of 100 octane use, it writes:

Then it goes back again how little American supplies meant in RAf plans, how limited the importance of 100 octane was compared to CSPs etc. There's no doubt some nationalistic odor to it.


Comparison table of FC's sorties vs. the amount of 100 octane and 'other' (ie. 87 octane) aviation fuel issued during the month clearly show that Figther Command was relying on 87 octane for a number of its operational fighter Squadrons.

http://i38.photobucket.com/albums/e1..._duringBoB.png

A few of my own observations:

a, It seems clear that 100 octane has begun replacing 87 octane towards the end of September / start of October. Until then, 87 octane is by far the major fuel consumed.
b, This corresponds with what the Lord Beaverbook memo noted about re-starting the conversion
c, Its also very appearant that issues have a bit of 'delay' built into them. Obviously supply's nature is that they re-supply after the fuel at the airfields has been used and there's reported need for new issues. This takes time.
d, 100 octane issue curves are clearly responding to FC sorties number increase/decrease. Though that's not news, FC used that fuel. But it should be kept in mind that number of Blenheim Sqns also used and were issued 100 octane fuel, and a Blenheim sortie would consume 4-6 times the fuel a fighter sortie would.
e, On the other hand, 87 octane issues ALSO clearly reacts to FC sorties number increase/decrease. It shouldn't, if all frontline Sqns would be using only 100 octane. ;)
f, Obviously the 87 octane curve reaction is less pronounced, as
fa, A good percentage of FC used 100 octane, so they don't their needs 'do not exists' from the 87 octane issues POV
fb, A large number of other aircraft also uses 87 octane, and many of them - bombers, patrol craft etc. - consume much more fuel than small fighters.

In my opinion, the most conclusive evidence that even towards the end of October a number of fighter squadrons were flying on 87 octane is evident by the sudden and perfectly parallel rise of both 87 octane issues and FC sorties curves at the time.

Tendencies to have British aircraft using only the best possible configurations are nothing more than the naked truth of gamers wanting more advantage to their aircraft, regardless of historical accuracy.

T.O low speed no ram effect + Optimum Air flow in term of Mass of air to cool the supercharger (see above what two speed use is abt)

@VO101_Tom : Nice found but I am sry this argument is not valid. Any Army makes the circulation of Info a strategical issue : you are flying in a fighter -> you get all the info cleared for your security level regarding that type of fighter.

It does not mean that they all hve used the famous 100oct

But As I hve alry said : let's give them their Barracuda engines that years of stupid mods can get a justification (and spare my own free time)

@Kurf : this is a neat explanation with proof reasoning. I hve read it the first time you put it on the forum and still wait for any argumentation since

All of this disinformation is more of the same, all put forward by you in the threads I linked from the WWII Aircraft forum, and all have been proven to be false.

You are a broken record Kurfurst, posting twenty times does not make a false statement anymore correct than if you post once.

Anyone who takes the time to read through the threads from WWII Aircraft will see how credible you are with your homemade tables and lack of original documents.

To deal with your point there was more 87 octane fuel issued, the reason was simple:

RAF Bomber command was conducting a night offensive throughout the battle, bomber fuel loads are roughly twenty to thirty times that of a fighter aircraft.

If you look at 100 octane usage, the figures are clearly in line with what consumption should be for the roughly 400 fighter aircraft based at 10, 11 and 12 Group fields. In 1944 and 1945, the whole of the 2nd TAF usage of 150 octane fuel was roughly 10,000 tons per month, and that was for over 900 aircraft, Spitfires, Typhoons, Tempests and Mustangs, all of which had larger fuel tanks, plus all of which were loaded with drop tanks for every mission, the drop tanks alone for '44/'45 aircraft held more fuel than a '40 aircraft held in its internal tanks. Drop tanks were not in use by the RAF during the BoB.

But I am not going to lay out all the arguments here, they have already been presented in the WWII Aircraft forum thread in more than enough detail.

Yes, I mis-linked 'Glider' with Gavin Bailey, the name Bailey actually uses in the thread is 'Gavin B', another 'G', in any case, Gavin Bailey clearly disagrees with Kurfurst in the threads, Kurfurst ends up insulting him and that is one of the reason Kurfurst is banned.

The links again:

http://www.ww2aircraft.net/forum/avi...2-a-20108.html

http://www.ww2aircraft.net/forum/tec...bob-16305.html

If was used continuously the 12lbs boost, and the engine was ruined continuously, it does not interest, if COD makes the same one. :)
If I misunderstood it, then excuse me, but the object of the debate in the other topic, that the 12 lbs were useful without the damaging of engine - from what it follows, that let COD not take it into consideration...

Buzzsaw, apart from your usual tirades and various lies about my person,

A, can you produce even a single primary document saying all of Fighter Command using 100 octane fuel and 100 octane fuel only?
B, can you explain, that if FC would use only 100 octane fuel, why do 87 octane issues suddenly rise at the moment Fighter Command is flying more operational sorties?

Should you be able to do so, I may be able to take you seriously.

GP! The bottomline though, the initial combat rating was clearly +9 (until november).

Because 87 octane is being used by Coastal Command, Bomber Command, RN, OTU and flight training units, all of whom will increase their activities during periods of good weather, which was when the Luftwaffe also increased it's activity over Britain.

+1

I will check that out, if it works it would be a great improvement, thanks!

No - 87 octane limited the engine to +6.5. In this period, the boost control cutout was a safety feature to permit the pilot to manually control the throttle valves if the ABC failed. Fully opening the throttle at sea level static would give about +17 psi boost. This would be very bad for the engine.

Of course, in theory you could operate the cutout and then manually set the throttle to provide any arbitrary amount of boost that the supercharger was able to deliver at your altitude.

So a Spitfire or Hurricane pilot in 1938 could have overboosted their engine anywhere up to about +17 on 87 octane. But this would have rapidly damaged the engine and would have been completely against the instructions in the Pilot's Notes etc.

I have seen no evidence that anybody did this deliberately (though doubtless somebody did it by accident, because if it's possible to do something silly then somebody probably will). However, it was obviously known that +17 would result from operation of the cutout in its initial state because this is clearly set out in documents which I have cited in my thread on the subject of the effects of operating the boost control cutout in Spitfires & Hurricanes using 87 octane fuel.

With 100 octane fuel, the engine could safely operate at +12. The boost control cutout system was then modified by drilling a bleed hole so that operating the cutout would now provide no more than +12 psi boost. This meant that the cutout could be used to provide a regulated level of emergency combat power instead of operating simply as a safety device.

The cutout could be wired "off" with thin wire, so that operation of the cutout would provide a tell-tale for the groundcrew. This was therefore a very elegant solution.

Climb power for the Merlin XX is +9 psi at 2850 rpm. This is the most likely source of your +9 figure.

Not at all. See above.

MS = Medium Supercharge
FS = Full Supercharge

Supercharger efficiency depends upon where you are on the compressor map. You'd generally plot non dimensional flow vs pressure ratio and include constant speed lines.

What you find is that centrifugal impellers are pretty forgiving machines, and will operate over quite a wide range of flows and pressure ratios at any given speed without surging.

Really you only care about tip speed for 3 reasons:

• Structural strength
• Supercharger power consumption
• Charge temperature

So ideally you want to run the engine with a wide open throttle and turn the supercharger at the lowest speed at which it is able to deliver the pressure ratio required to give the boost you want at your current ambient conditions.

But this would be too complicated for 1940.

So you compromise.

The Merlin XX had a 2 speed supercharger drive gearbox, so 2 compromise speeds were available instead of 1 for the earlier engines. This allowed better overall performance, though it didn't have any direct impact upon peak power.

Farman patented the gearchange mechanism; RR just licensed the IP. IIRC there were a couple of other gear change mechanisms on the shelf, and some of the Packard engines may have used a different one for production reasons.

In any case, it was an IP licensing thing rather than a case of Farman having specifically produced technology with the Merlin in mind.

Merlin without supercharger = Meteor. It would give something in the region of 650-850 bhp. It's quite hard to be concrete because Meteors were generally reconditioned (ie crashed, non-airworthy) Merlins and so they were never going to perform "as new".

~S

The Merlin III was allowed the use of 16lb boost on the Sea Hurricane IB, so I doubt that 17lb boost would be instantly fatal with 100 octane fuel, but with 87 octane bad things would happen.

You mean just like he said? He never mentioned 100 octane fuel, he is specifically referring to 87 octane fuel in that scenario. Why is it that whenever anyone mentions a Merlin engine could blow up you have to jump in to save the day and explain to all us mere mortals why the Merlin was perfect.

-1

It does not work, yes you can move to center the gunsight but as soon as you turn the TRACKIR on, it centers again automaticaly to normal view.


What a bunch of rubish! :(

Pls take a close look at your doc - Merlin XX. I hve here maximum perf calibration with max speed being plotted. It does not look like anything like a climb setting

Oh and it does come from RR..


I don't see the sense of what your wrote here. You might hve pasted half the sentence from your original doc here ;)

physically given that the SC is accordingly dimensioned (flows and struct) , the heat generated is what will drive the overall efficiency. And what drive away that heat : the flow of air (or air mixture) that is pushed by the impeller blades.

Hence there is a max amount of calorific E that a s/c can work with. Raise the oct -> you'll reach sooner the the max sustainable value

This is why I said that Max boost level hve very little chance to be reachable at an alt where the impeller hve alrdy to compensate for lower air density if the eng was not designed for

etc... etc...


Modern supercharger : yes. At the time of BoB hummm that's a pretty acrobatic assumption

pls see the above

I wld hve been pls to see a Farman 220 with 4xMerlins. Damn just to see that huge parasol wing being blown away by the engines airstream :rolleyes:

By the way, most patent are cross border documents. There is no shame using a Patent from an other country. Aviation is full of this. let us remind that if Aviation pioneer did not get inspiration from each other all over the world, we wld still cross the pound on steaming boat.

Supercharging the eng was meant to keep power at alt (the rated alt) and increased the fighter perfs (smaller engine) where the bomber stream were expected . This is not NHRA supercharging although a direct benefit were a low perf improvement and climb rate to alt.

I hve arldy quoted the Merlin XX data with and without s/c (your 12lb thread)

You'd see that the s/c being driven by the eng shaft use a 7 to 20 % of eng power. Hence teh 1.3k SHP and 1.175k BHP or something like that

Anyhow, the team that did code those FM game have proved superior man skills in the field. I am looking frwd for the next released giving they can work without too much pressure away from 1C SC
(read Spit Complex )
~S

No. The efficiency is the ratio of useful work to input work. In general, we'd use the isentropic adiabatic compression work for the pressure ratio achieved by the system as the definition of the "useful work".

This makes no sense.

Better fuel = higher max charge temperature, all other things being equal (which they are for merlin development as the basic piston engine (bore, stroke, CR, valve timing, max rpm etc were the same throughout its production life).

The engine is flat-rated to a maximum safe boost pressure. The supercharger is designed to deliver this boost WOT at the FTH. Below FTH the supercharger is throttled.




Not really. Compare the ease with which RR developed their centrifugal flow jets with the massive difficulty they experienced trying to get the AJ.65 to work. It's all relative.

Modern compressors of all types will have better polytropic efficiency and deliver more work per stage, but the basic trends haven't changed.


I work with patents quite frequently, and hold a couple of my own. They're only cross border if you've got the money to chase the legal paperwork, and they only mean anything much at all if you've got the money to sue whoever might infringe... I don't see why you'd ascribe any particular moral value to the nationality of the inventor to whom a patent you've decided to license is attributed. Most engineers have better things to do...

Supercharging is really about making the engine smaller.

The non dimensional flow that a piston engine can handle at fixed rpm is basically constant.

Supercharging allows you to cram more absolute mass flow rate into a given non dimensional flow rate.

How you choose to rate the engine is another debate. But in most cases, people only flatrated because fuel quality prevented them from operating WOT at lower altitudes.

No, your data quotes the power consumed by the supercharger, and the power produced by the engine.

This is not the same thing as operating without the supercharger. Without the supercharger you can't get above 0 boost by definition. Hence you get something like 650-850 bhp.

Obviously the Supercharger consumes fewer horsepower than it adds via the boost increase it creates - otherwise nobody would bother!

Superior to what? It's not as though there's a whole lot of competition in the Flight sim market these days...

At first I wld like to say that I'm sry to all reader for this dual exchange.

Secondly I did not quote you to shorten those otherwise long answers that tend to be felt as walls in a forum pulling away the reader interested by the title of this topic

Let's go :

Adiabatic = when E is exchanged without loss of Calorific energy

Simply said the s/c depend of it's operating inside Temp that drive the efficiency of the compression

There is no adiabatic transformation. Isentropic is also an approximation to figure out the inside Temp that RR could not measure in 1940. But yes that what you plot. But who cares ?

Better fuel : higher piston head temp -> eng wearing. This is well known from car's tuner. You'd see a lot of interesting threads on that subject without over complicated words.

By the way the DB605 is no more than a revamped DB601 but with the same minor details that change and took so little time to arrange before being sent in full production

Wasn't WOT 5000 ft ? -> it's far from any rated alt - look like more for a naturally aspirated eng. I guess that the redesign of the intake was the partition they played here ;)

Yes yes you 'r right impeller are quite easy technology once you 've got the backup of strong industry supplying nice raw materials proof of any small glitch. Oh yes you'r right ... Of course the Russians, The Italians and the Japanese just might hve miss read the same early studies.

Si vis pacem para bellum : UK proved here her superior "governing awareness" (despite the Munich debacle)

RAF not NHRA :rolleyes:

Using copy/Paste as well :

Merlin XX !!

ALT(ft) SHP BHP (diff correspond to the power used to drive the supercharger)
15K 1267 1048
20K 1298 1073
20K+ 1362 1126
25K 1162 960
30K 945 778
35K 700 568

At 20K the eng is fed with sufficient amount of air to regain is low alt power. But it still hve to drive the s/c. This everything abt turbo-charging an eng.

FM : 1c far superior to any Modder (I am sry to hve to write that)

Patents ? I never doubt you was a talented individual. Well let's pat our back and share our patents together one day ;)

In terms of Bomber Command usage, the pilot's operating handbook for the Blenheim Mk.IV confirms the above points.

Actually, the Mk.IV used both types of fuel.

What happened?
1) They needed more range so they added two more fuel tanks, one in each wing (the outboard tanks).
2) This made the aircraft heavier so it needed more power to get off the ground safely when fully bombed-up and fueled.
3) Engines were modified and a boost cut-out installed, so that maximum boost could raised from +5 lbs to +9 lbs.
4) This needed fuel with more resistance to detonation (aka 100 octane), but it was also important for Fighter Command use.

So, what they did was load 100 octane only in the outboard tanks and use 87 octane in the inboard tanks.

When loaded for long range, takeoff was done on 100 octane fuel from the outboard tanks with the boost over-ride enabled and +9 lbs boost, then immediately after take-off they throttled back and switched to 87 octane from the inboard tanks.

When flying shorter range sorties only the inboard tanks were loaded with 87 octane and the normal maximum of +5 lbs boost was used, in order to let the fighter boys have more of the 100 octane supply.

Another consideration was that only the outboard tanks had jettison valves. So, they used the 87 octane fuel from the inboard tanks first, during the climb out and cruise, because in the event of an emergency they couldn't dump it. Then they switched to outboard tanks and 100 octane fuel for the remainder of the trip.

The ability to use +9lbs when running on 100 octane as an emergency rating would probably factor in tactical considerations as well, so maybe they switched to outboard tanks when in dangerous airspace or over the target/during the bomb run, just to be able to pull the boost cut-out and throttle up to +9 if they needed.

In case of a long-range run (like the raid on the Cologne power station on August 12th 1941), this would probably mean using 87 octane on the outbound leg, switching to 100 octane near the target, switching back to 87 octane once outside the "danger zone" (if any was still left in the tanks) and finally, switching back to 100 octane fuel for the remainder of the trip back home.

In any case, this could make up for a sizable part of fuel expense for both types of fuel, especially if we consider that during the BoB they were operating throughout the battle:
a) in the long range reconnaissance role (as far as Germany itself) and
b) attacking targets as far as Denmark.

After the description of their manufacturing restrictions and resulting operating procedures above, it's more or less clear that the more far-away a Blenheim target was the more 100 octane fuel would be used, since close-range targets would only need the inboard tank fuel load and could be flown solely on 87 octane fuel (less weight, less boost needed for take-off-->no need for 100 octane)

The difficult part here is getting a similar graph for Blenheim sorties and factoring in target range, so that we can actually know how much of the 100 octane fuel expenditure could be attributed to them.

I don't have the wealth of references some of you guys have, but i thought this might interest you and you may be able to dig deeper into it ;)

Salute

Thanks for the info Blackdog.

And of course, the Blenheim was only the smallest of the bombers which the RAF had available and was the only bomber to use 100 octane, but as you say, only in the outside wing tanks, and only for takeoff.

Bomber Command had 207 Armstrong Whitworth Whitley's the 33,000 lb heavy.

They had even more Hampdens, over 250, as well as close to 200 Wellingtons. All these bombers used huge amounts of 87 octane fuel, they flew missions all over Northern Germany, as far as Berlin, many times the range of the short hops the fighters made in their intercepts.

In addition, coastal command aircraft also flew constant patrols, over very long distances, the anti-U-Boat campaign was already a major priority.

All of this explains the heavier usage of 87 octane fuel.

Hallo David,
You asked a rather simple question and I am afraid your thread got kidnaped :D

I think the best book to have and read is:
Fighter combat: tactics and maneuvering by Robert L. Shaw
as it explains the differences between maneuveurability and speed and tactics against different types of oponents.
Despite that, there are some serious "deficiencies" in the CoD aiplane models (judging by the tenacity people argue about their 87oct vs 100oct fuel (I do not belong to this club)) and "deifiencies" in the game graphics engine (low quality ground, small size representation of enemy planes, head movement restriction) which will considerably hinder your capability of applying what you will learn in this book in practice in this game.
Usualy the best solution to solve the problem is flying in pairs (with a wingman) and everybody covers each others back. This is the only technick that always work, even against massively superior opponents (e.g. the "Thatch-wave" technik American pilots used in the Pacific as the only way to defend their Wildcats against the vastly superior Zeros) but it requires in most cases that you enter a squadron and train a lot in navigation, formation flying, deflection shooting and voice communications in order to perfection the art of wingman.

Sorry I could not give a quick and simple solution.

~S~

true,but it turned in an interesting debate.
thx for the book recommendation.i will buy it if i find it.i thought a lot of times about joining a squadron...may be its time to become a member of one.

[QUOTE=Blackdog_kt;297896]In terms of Bomber Command usage, the pilot's operating handbook for the Blenheim Mk.IV confirms the above points.

Actually, the Mk.IV used both types of fuel.

What happened?
1) They needed more range so they added two more fuel tanks, one in each wing (the outboard tanks).
2) This made the aircraft heavier so it needed more power to get off the ground safely when fully bombed-up and fueled.
3) Engines were modified and a boost cut-out installed, so that maximum boost could raised from +5 lbs to +9 lbs.
4) This needed fuel with more resistance to detonation (aka 100 octane), but it was also important for Fighter Command use.

So, what they did was load 100 octane only in the outboard tanks and use 87 octane in the inboard tanks.

etc. etc.


Hi,

I generally agree. I've heard of Blenheims using 100 octane in the outer tanks only for boosting purposes (presumably take off with heavy loads as you say). I don't have the Blenheim manual, unfortunately - do you have link perhaps?

OTOH, the documents supplied by Glider suggest that the actual modus operandi was to have select Blenheim stations at No. 2 Group (Wytton, Watton, Wattisham, West Rayam) receiving only 100 octane fuel, with 87 octane removed at the same time from the storage tanks. I suppose this was probably done to avoid nasty incidents of mistakenly filling tanks w. 87 octane - its rather unhealty to loose all power due to engine failuire in heavily bomb laden bomber on takeoff..

http://i38.photobucket.com/albums/e1...meetingA-1.jpg
http://i38.photobucket.com/albums/e1...MeetingB-1.jpg

Given the above, I believe in practice these Blenheims concerned were fueled with 100 octane only.

Indeed it is complicated I fully agree. As a rough guess, I presume that assuming 5 times the consumption for a Blenheim Squadron compared to a S/H fighter squadron is a reasonable assumption, given they had twice the engine and at least twice the range to target.

I guess nobody here can take you seriously, then.

Geez....

You people are still debating this? Where is the common sense?

:o

We know that the RAF was using vast amounts of 100 octane fuel. If RAFFC wasn't using it, who was? You have never produced a single document stating that some of RAFFC was still using 87 octane and the burden of proof is upon you.

Flight activity of all kinds will increase with good weather. This is such a simple concept, that it will be instantly apparent to almost everyone.

http://i38.photobucket.com/albums/e1..._duringBoB.png

The RAFFC flew 5700 sorties and the RAF issued about 4500 tons of 100 octane fuel during the 1st week of September. 5700 sorties at 75 gallons per sortie = 427500 gallons or 1374 tons (assuming every fighter does a dead stick landing with empty tanks, it only rises to 1650 tons). This leaves more than 3000 tons for use in RAFBC and all other assorted and sundry users, more than enough for every twin engined Merlin bomber and fighter to be using 100 octane fuel and still leave lots left over for use by RAFFC.

There is too much things that does not match

Not really, what i said was indeed "only in outboard tanks" but it is far from saying "only for takeoff": unless they were planning a one-way trip they would have to burn that 100 octane on the return leg of the sortie as it was the only supply available to them after the inboard tanks had gone dry :-P

What i previously described amounts to "on takeoff and half of the cruise portion of the flight", which is half the fuel burn for the sortie.

In other words, quite a lot of 100 octane fuel in case of long range sorties and as low as none at all in short range sorties (unless they were bending the rules and carrying a few minutes worth of it to get better WEP boost values in case of trouble, but that would be a negligible amount).

In conclusion, if the Blenheims generated enough sorties at long ranges or were routinely tasked with loitering around a certain area on patrol duty (eg, U-boats, reconnaissance, etc), they could account for quite a lot of 100 octane use. If on the other hand they were mostly flying cross-Channel hops in nuisance raids, they would mostly burn 87 octane.

Until someone can produce a relevant document that deals with the amount, type and range/duration of their sorties during the BoB the argument can swing either way ;)

This might prove relevant:


"the Bomber Stations concerned was practically complete (these Stations are Wyton Watton, Wattisham, West Rayham)"

http://www.ww2aircraft.net/forum/att...ng-minute-.jpg

Quite clearly only four Bomber/Blenheim bases were 'concerned' with 100 octane fuel. If those four stations held all Blenheim Squadrons, your claim may be true, but somehow I doubt it.

Wyton had two Blenheim Squadrons at the time: Nos. 15 and 40
"In December 1939, both Wyton squadrons were sent to France and Nos. 15 and 40 Squadrons returned from the Continent to Wyton, the first step in converting Battle squadrons to Blenheims. Both squadrons flew their first bombing raids from Wyton on May 10, 1940 against targets in the Low Countries. The Blenheims of No. 57 Squadron were based briefly at Wyton in June before going south, returning for two weeks the following month before flying north only to appear again at Wyton in late October. "

Wattisham had also two, Nos. 107 and 110 Squadrons http://www.raf.mod.uk/bombercommand/s30.html
http://www.raf.mod.uk/bombercommand/s106.html

Watton also had two Blenheim Squadrons: Nos.21 and 82 Squadrons
http://www.raf.mod.uk/bombercommand/s31.html

West Rayham had only one Blenheim Squadron, No. 139, and possibly from June 1940 also no. 18 also operating.

That's 7 or more like 8 Blenheim Squadrons on 100 octane. At that time there were 15 Bomber Command Sqns. operating Blenheim IVs. But this pretty much explains where 100 octane fuel went in such quantities - even those 8 Blenheim Squadrons were consuming a lot. Total tankage was 468 imp. gallons compared to 85 gallons on the Spit - a worth of about 45 Fighter Squadrons.. ;)

No.
468 gallons is with no bomb load
Total internal fuel capacity was 280 imperial gallons, or less, when used as a bomber. Normal TO weight = 13500 lb and 14300lb max.

Empty weight = 9790 lbs
Bombs = 1000lb
crew = 600 lbs
oil = 200lb (28 gallons)
fuel = 280 gals = 2016lb (468 gallons = 3370lb and 15300lb TO weight with 1000lb bomb load)
------------------------
= 13886lbs, when normal max was 13,500lbs and overload = 14,400lb

13500lb = ~230 gallons with a 1000lb bomb load.

Most BofB Blenheim missions were tactical strikes into France or as fighters where even 230 gallons was far more than was required.

[QUOTE=Seadog;298133]We know that the RAF was using vast amounts of 100 octane fuel.

5-10 000 tons a month - out of 50 000 tons total per months or compared to about 90 000 tons per month consumed by the Luftwaffe is hardly 'vast amounts'.
Its a tiny amount, even compared to 1940 overall or later RAF consumption.


Bomber Command (at least 8 Squadrons of Blenheims for example), engine manufacturers for running ins and testing, Squadrons for non-operational flying and practice. One Squadron in August 1940 for example did


Of course I did. Ironically, just two posts above. Besides yo simply display the logical fellacy of the Invisible Pink Unicorn: you seem to believe that if you claim something, without being capable proving it, and if others don't prove you wrong, you are automatically right. Right? Well, its just utter nonsense. See: http://en.wikipedia.org/wiki/Invisible_Pink_Unicorn

All Figther Command Aircraft were operating on 87 octane previously; in March 1939 a decision was made to convert sixteen fighter Squadrons to 100 octane by September 1940, and in around May 1940 it was noted that 'certain' fighter squadrons were to be supplied with 100 octane fuel.

Certain, not all. Well its not too hard figure out what the other-than-certain Fighter Squadrons were still running on, my dear Watson?

http://i38.photobucket.com/albums/e1...meetingA-1.jpg

That's an interesting claim. Can you tell me how much 100 octane was spent on operational training, engine testing, run-in, was used up by Bomber Command's Blenheims etc..? Without that, your calculation is an extremely crude and wishful example..

RAFFC had about 45 Merlin engined fighter squadrons and 5 Blenheim Squadrons operational under RAFFC command on July 08. About 10 - 12 Hurricane, non operational squadrons were forming up.

so lets say that RAFFC had 57 operational squadrons during the 1st week of Sept. 57 squadrons into 5700 sorties = 100 sorties week/squadron. Lets assume 15 Blenheim squadrons (5 x RAFFC and 10 X RAFBC) = 1500 sorties at 230 gallons/sortie = 1108 tons of 100 octane. So our 5 Blenheim squadrons flew 500 of RAFFC's sorties leaving 5200 to be flown by Merlin engined fighters @ 75 gallons/sortie = 1254 tons, so total RAFFC and RAFBC 100 octane use = 2362 tons. This is only about 1/2 the total consumption of 100 octane and it accounts for 5200 SE fighter and 1500 hundred twin engined Blenheim sorties. There simply isn't enough 100 octane fuel users left over to consume the ~4400 tons if RAFFC isn't using 100% 100 octane.

According to the graph you supplied, the RAF used about 15000 tons of 100octane and ~ 24000 tons of other grade during Sept 1940. How much 100 octane did the Luftwaffe use?


Can you present evidence stating that even one RAFFC Merlin engined squadron was using 87 Octane from July to Oct 1940? If I was an RAFFC pilot and my Hurricane/Spitfire was using 87 octane, when the squadron down the road was using 100 octane, you can be sure that I would have mentioned it my memoirs or complained about it while writing up a combat report: "The Ju-88 got away because I couldn't use overboost..." Yet there isn't a single statement anywhere about RAFFC pilots complaining about the lack of 100 octane engines or fuel, during the Battle.

Did they complain abt the lack of reheat on their Jet engines ?

I wonder, is there a single statement anywhere about Luftwaffe pilots complaining about the lack of 100 octane engines or fuel, during the Battle..? Or the Italians..?

Yes...

Does the history work so? Did you read this book? You would quote it what wrote in the next sentences?

What a tool, and you wonder why nobody takes you seriously.

Here is a quote directly from the book as made by Galland (you obviously haven't read it).

"The theme of fighter protection was chewed over again and again. Goering clearly represented the point of view of the bombers and demanded close and rigid protection. The bomber, he said, was more important than record bag figures. I tried to point out that the Me109 was superior in the attack and not so suitable for purely defensive purposes as the Spitfire, which, although a little slower, was much more manoeuvrable. He rejected my objection. We received many more harsh words. Finally, as his time ran short, he grew more amiable and asked what were the requirements for our squadrons. Moelders asked for a series of Me109's with more powerful engines. The request was granted. 'And you ?' Goering turned to me. I did not hesitate long. 'I should like an outfit of Spitfires for my group.' After blurting this out, I had rather a shock, for it was not really meant that way. Of course, fundamentally I preferred our Me109 to the Spitfire, but I was unbelievably vexed at the lack of understanding and the stubbornness with which the command gave us orders we could not execute - or only incompletely - as a result of many shortcomings for which we were not to blame. Such brazen-faced impudence made even Goering speechless. He stamped off, growling as he went."

So Galland even in his own book states he preferred the 109 over the Spitfire and that his quote was made purely to get at Goering. How can you expect to be taken seriously when you twist words and meanings to suit your own agenda?

+1 :rolleyes:

Never seen someone's credibility evaporate quite so quickly.

So Galland asked for Spitfires and Moelders wanted 100 octane Me109s...

Work on your reading comprehension skills a bit?

Galland asked for spitfires facetiously, because he was receiving orders from above that the escort fighters were to stay close to the bombers, a role to which the spitfire was better suited than the 109. He was trying to make a point that his fighters were not being used to their strengths, not that he felt the spitfire was superior.

Similarly Moelders did not ask for "100 octane 109s" since the Germans didn't classify their fuel that way (and in some cases measured the octane number differently). He asked for 109s with more powerful engines.

Luftwaffe fighter pilots, like all fighter pilots, wanted aircraft with better performance. This is abundantly clear from the above quotes and they pressed their claims with Goering himself! One way to get better performance was through the introduction of the 100 octane rated DB601N engine and it is clear that Luftwaffe fighter pilots were pressing for its introduction...( I can't wait for the torrent of claims that Luftwaffe pilots "didn't want any stinking 100 octane rated engines...":rolleyes:) RAFFC pilots also wanted better performance, and they got a complete transition to 100 octane fuel, a transition which was completed prior to the start of the battle.

Salomonic hipotetic solution: Luftwaffe must buy some A6M2 Zero(Or buy the licence)and everybody is happy.

His exact words were "Moelders asked for a series of Me109's with more powerful engines."

You can't just make stuff up and attribute it to a historical figure. You don't really know what octane the pilots wished they had, did you?

The Germans generally didn't concern themselves with RO Numbers; their fuel was graded alphanumerically. C-3 fuel was what the Allies would have called 130 Octane fuel (150 after 1942 IIRC).

Fighter pilot don't give a damn about octane ratings except to get more power. One way to get more power (at least on the Merlin) is to run the engine on a higher octane fuel and increase the boost pressure. RAFFC did this to every Merlin powered fighter in its operational inventory, and thus no pilots are recorded as wanting 100 octane fuel, "like my pal has in the squadron done the road".

Luftwaffe pilots also pressed for "more powerful engines" and again high octane fuel made this a much easier proposition. Asking for more power is exactly the same as asking for higher octane fuel. ( I didn't have to wait long for the "we don't need no stinking 100 octane fuel" claims from the Lufters...:-P )

Couldn't agree more.

Please quote where I said that.

Source please. Oh wait, we have your word for it, and everything it worth for. :D

No comment :D

We have a source:

https://lh4.googleusercontent.com/-0...lin_100oct.jpg

and you have not presented a single shred of evidence to contradict it.

Of course you have no comment. The whole point of 100 octane fuel was give engines more power through higher boost pressure, and no RAFFC pilot flying a Merlin engined fighter during the BofB is on record of complaining that he can't use overboost, and so was deprived of 30% more power than his buddy in another squadron.

As I said earlier, absence of evidence does not imply evidence of absence.

Your source, if I remember from way back in the thread, is a 3rd-party book. I asked if they had references since this is not a primary source and you ducked the question.

I didn't duck it. We have a source that states that RAFFC went completely to 100 octane, and there is no source that states that this is incorrect, and there is a large body of evidence that supports the view that RAFFC used 100% 100 octane fuel operationally during the BofB. If you don't accept the above source, than present some evidence that from July 10 to October 30 1940, that even a single RAFFC Merlin powered squadron was using 87 octane during combat operations.

There was about 46 RAFFC Merlins engined fighter squadrons available on July 08 1940. Surely you can find evidence that one of them was using 87 octane operationally during the battle. Just one...;)

Yes there is a primary source that refutes the secondary source you posted, Seadog.

The seventh conference on 18 May 1940 clearly states that certain units in Fighter Command will make the switch.

That document has been posted ad nauseum.

As this on going fuel debate....

The best source on German Aviation Fuels is the Fischer Tropsch Archives.

http://www.fischer-tropsch.org/

They have a good collection of documents online anyone can learn about German fuels. Allied Fuel and German fuels were not directly comparable.

B4 is slightly better than 87 grade Allied fuels and is roughly equal to 91/~115 octane.

C3 began as the equivalent to 100/130 grade allied fuels and was later improved to 100/140 grade which allowed such improvements as a straight manifold pressure increase without additional knock limiting performance enhancement to 1.62ata in the BMW801D2 series and 1.98ata in the DB605 series engines.

C3 was adopted in 1940 and was used during the BoB.

http://img40.imageshack.us/img40/3662/c3inthebob.jpg

The whole debate is silly and pointless. The arguments are put forth by gamers to make their personal game play more enjoyable such that a game shape performance can overcome their own inadequacies. It is an agenda advanced by clowns who focus on whatever specific portion paints the desired picture without regard to the whole.

The facts are the German fuel was roughly equal but on the whole slightly inferior to the natural petroleum. The Allied fuels were better but allied engine technology could not take full advantage of their superior fuels. The German materials technology, chemical engineering, and fuel metering technology was much better and made up for the lower quality fuels.

Just the fact the Germans had direct fuel injection technology and the allies never did balances any fuel differences. One can make considerable power gains without changing fuel type just by changing the fuel metering system from a carburetor or Throttle Body Injection to Direct Injection. In a 1000 hp engine, you can expect to gain 80-150 hp just by changing the fuel metering method.

The whole debate ends up being a wash.

Its not true. Moelders asked for a series of Me109's with more powerful engines. DB 601 A-1, DB 601 Aa, DB 601 N, later DB 601 E (for F), DB 605 engine family (for G-K). All were stronger than the previous type, without it that they would use the 100 octane C3 fuel instead of the 87 octane B4 ones. Of course, if they use C3 fuel, MW30, MW50, or GM1 system, the strength of the engine is growing rather yet. But purely visible, that it is possible to make stronger engine, using the same fuel (B4):

http://www.enginehistory.org/German/DB/Fig00.jpg
http://www.enginehistory.org/German/DB/Chart01.jpg

and the accepted dates for the BofB are July 10 to Oct 30, 1940.

Seadog,

18 May 1940 is only 6 weeks from the start of the Battle of Britain.

The language in that primary source document refers to "certain units" and not "ALL" units.

Very importance difference.

The German Army defeated France in 6 weeks...6 weeks is a long time.

RAFFC had many units which did not require 100 octane, such as OTU and a few squadrons of Gladiators. In any event, again all the evidence points to RAFFC operational Merlin engined squadrons using 100% 100 octane. There isn't a single source that states that an operational Merlin engined fighter squadron was using anything else.

No it's not. An engine of a sufficiently bigger displacement running "normal" fuel with the appropriate boost values will still outperform an engine with a lower displacement. If they have similar displacement a smaller engine running 100 octane could reach or even surpass the HP of a bigger one running 87 octane, but a sufficiently bigger displacement would ensure superior performance even when running fuel of a lesser octane rating.

And that's without even taking into account other things like supercharger design and gearing and propeller design, things which affect not only the powerband of the engine but also the appropriate altitudes where the extra power can be better used.

What i'm trying to say is that asking for engines with more HP can mean a combination of many different things. When you are discounting them all and pretend its only the octane rating that matters you are just simplifying for the sake of pushing a personal viewpoint without having to come up with the supporting proof: "they asked for more power, so they should surely mean a better octane rating".

I'm all for Spits and Hurricanes getting their 100 octane and constant speed prop variants. Keep the current ones for battle of France scenarios (i mean we already have much of the map so why lose the ability to create such missions) and let's also add the proper battle of Britain variants.

I'm also in favor of having a 50% chance (or whatever the appropriate percentage was) of spawning with DB601N engines on your 110, which you make absolutely no mention off in any of your arguments. I've given you the benefit of doubt until now but you're gradually exhausting that reserve.

No offence meant and i'm not saying you're just pushing for a gameplay advantage for your favorite ride because i'm not the kind of fool that will pretend to know what's in another person's mind. What i'm saying is that you sure sound like that more and more as time goes by, i just don't have a way to confirm it, which makes me averse to getting convinced out of a matter of principle. I guess this goes for many others as well.

1) Again, pilots wanted more power. In the Merlin III, 30% more power was available through a simple mod, that could be done in an afternoon using fuel that was readily available. RAF pilots had been aware of this for several years, and they got a full transition to 100 octane prior to the BofB, indeed many France based Hurricane squadrons used it during the BofF. I don't and haven't discounted other options, but raising displacement, for example, invariably means greater weight and greater frontal area, something that pilots don't want.

2) see my post #71:
http://forum.1cpublishing.eu/showpos...1&postcount=71
By all means, include all historical engine and aircraft variants.

3) No, I am pushing for a game that sims RL. In RL Merlin III aircraft have access to much higher power at low altitude. At high altitude these advantages dwindle and the Me109 has many advantages, and this will force the Me109 pilots to fly as per RL, IE, stay high, and fight in the vertical. Dogfighting Hurricanes at low altitude is not a great idea. The RAFFC made a rapid transition to 100 octane engines and CS props and it was a much tougher proposition than the Luftwaffe had been led to believe, but thats how it was.

Compared to that theory, German DB 601 was same size as weight as single stage Merlin, 605 actually lighter then two staged Merlin, while the French 35-liter class Hispano Suize V12s were considerably lighter than both.

The only practical way a smaller displacement engine can keep up with larger ones is by heavy supercharging, but that does not comes free, superchargers and their systems add weight, and so does decreasing fuel effiency: more fuel need to be carried for same range.

They are similar, but the Merlin is a bit lighter:

https://lh3.googleusercontent.com/-v...N_MerlinXX.jpg
from Flight, April 16 1942.
The net dry weight of the DB601N is stated in the article to be 1400lbs, but OTOH, Merlin engines were being run at much higher boost pressures when this article was written and thus greater power.

A Merlin III/XII/45 net dry weight = 1375/1420/1385lb

The article states that the DB601N had greater frontal area:
http://www.flightglobal.com/pdfarchi...0-%200807.html
and an article on the Merlin XX:
http://www.flightglobal.com/pdfarchi...0-%200449.html

Check the math on that document....

1430lbs / 1175hp = 1.21 lb/hp not 1.13lb/hp....

The Merlin has the same power to weight at the DB601.

It actually states 1450 lbs but also 1240hp at 2850rpm @ 10,000ft (two values given for the Merlin XX)

However, the DB601N power is WEP. The equivalent figure for a Merlin XX would be 1485hp at 14lb/3000rpm @ 6000ft and 1490hp at 16lb/3000rpm @ 12500 ft and 1280hp at 3000rpm/12lb @ TO, at least in 1942 but the TO figure is applicable to 1940 as well.

you actually implement that in a comparision wep is set against full mil.????
You are talking about the N, not the A.

The document compares the operational engines at the time it was prepared. At 17500 feet, the document is correct in the power output of a Merlin XX at it's approved Emergency Power rating of +9lbs at the time the engine were compared. It is also correct in its assessment of the DB601N series.

It is not correct in its math of the power to weight ratio of the engines. The Merlin XX is the same as the DB601N.

You need to look at the DB605 series to compare those other ratings. Also ensure you are looking at the correct power, ie...indicated, static or RAM, Brake or Thrust, and if it takes into account exhaust thrust...

In Nov 1940 the operational limits of the Merlin XX were 12lb/3000rpm TO = 1280hp, and 12lb/3000rpm @8500ft = ~1360hp in MS gear. Operation of the boost cutout would give ~14lb in FS gear, but I don't know exactly when official approval was given, however this capability was present in all Merlin XX engines.

At 1280hp and 1450lb weight gives lbs/hp = 1.13 but I agree that the values given in the chart were confusing.

So I understand now what's all abt lol; You hve been so scared abt the dynamic capacities of the Spit ? The guys that did mod the FM in IL2 did used badly wrong assumptions.

Stay at high speed . Don't over G. Don't put yourself where you'll need AoA and I swear you'll knock down any 109 even at full mil power. Big wings are made for that !

Damn Seadog Is that really a "Cat" tht hve to ensure you on this point ?!! :rolleyes:

Actually, if you do the thermodynamic analysis, you'll tend to find that supercharging doesn't particularly damage fuel efficiency, provided that you have reasonable component efficiencies and make a fair comparison (which is the difficult bit).

Power:weight at sea level will tend to be fairly insensitive to supercharge because the supercharged engine sees higher pressures and therefore has to be heavier, whilst OTOH the unsupercharged engine is bigger. So you end up with a small area of thick metal vs a large area of thick metal.

The supercharged engine has a higher power density, and this will tend to make life harder for the cooling system.

If you compare at fixed cruising speed, there will be an optimum degree of supercharge, beyond which you'll lose more from the increased cooling problems than you've gained from the smaller engine. OTOH, because the supercharged engine is smaller, it has less non-cooling drag, and so you'd expect to cruise faster, which helps to make the radiator smaller.

In the end, the trade space is complex, and it isn't especially easy to make a general case that one approach to engine design is better than another. Hence the diversity of engine designs; if there was a trivial optimum then engine designers would have swiftly converged upon it, and the world would be a much less interesting place.

Direct injection isn't necessarily the best approach.

If you're supercharging then putting fuel into the flow upstream of the supercharger will cool the flow by about 25 K due to the latent heat of evaporation of the fuel.

This considerably reduces the compression work required from the supercharger, which is equivalent to an increase in its polytropic efficiency.

I would suggest that the mixture distribution is likely to be pretty good downstream of the supercharger under design conditions, because the fuel is completely evaporated.

Direct injection will obviously achieve better mixture distribution at low rpm where the supercharger delta H isn't sufficient to guarantee that all of the fuel is evaporated. So DI will give you better performance close to idle. This is very important for car engines, but not so much for aeroplanes.

Furthermore, as you develop your engine and increase the amount of supercharge, you'll tend to cruise higher. Even at constant boost, you'll see a higher supercharger delta H and higher charge temperature, which makes the advantage of adding fuel upstream of the supercharger more important.

It's also much easier and cheaper to make and maintain a single point fuel injection system (be it via a pump or a carb) than it is to make individual injectors for each cylinder.

http://www.flightglobal.com/pdfarchi...0-%200562.html
http://www.flightglobal.com/pdfarchi...0-%200563.html
http://www.flightglobal.com/pdfarchi...0-%200569.html

If direct injection really was so great for piston aero-engines, the chances are that the Allies would have adopted it immediately post-war when all Axis technology was theirs for the taking. The fact that they didn't do so speaks volumes.

See also:
http://www.wwiiaircraftperformance.o...in-lovesey.pdf
(The chronology of engine ratings and outputs may also be of general interest; presumably Mr. Lovesey counts as a primary source...)

But engine design was heading towards turboprops in those years (and obviously turbojets), what with the "trent-meteor" hybrid that was instrumental in the development of Rolls-Royce's Dart engines.

http://www.automobilemag.com/feature...ion/index.html

Single point injection has no advantages over direct fuel injection at all. The Supercharger is on a completely separate circuit and the engine still receives all the benefits of supercharging with the additional benefits of direct injection.

The Allies did not have any direct injection engine technology to use.....

They could not make direct injection workable or practical using their fuel metering technology. Bosch's design, up until recently was the pinnacle of direct injection technology. It requires very high fuel pressures and the German system used a high pressure pump for each cylinder.

As already pointed out, post war, the turbine was supreme so why would any nation waste resources for a post war piston engine aircraft?????

Great Wartime article Viper. Thanks for posting that.

http://www.flightglobal.com/pdfarchi...0-%200569.html

http://www.flightglobal.com/pdfarchi...0-%200563.html

http://www.flightglobal.com/pdfarchi...0-%200562.html

An article definitely written to contain the public relations damage from intelligence on German fuel metering technology.

Rolls Royce's basic message is the German engines are not as efficient as they could be and only somewhat more efficient than the our engines.....

AND we can make a carburetor heat system that will overcome icing....

:grin: