Late Me 109 G & K engine settings

[Guppy35]

Originally posted by Staga
So where does it say they didn't had jettisonable tanks?
At least Pilot's Manual for Spit MkV gives fuel loads with 85Gall in aircraft + either 30, 90 or 170 Gall. drop tanks.

I suppose you are going to want the date that tanks were first used operationally?

Keep in mind these are early Mark Vs with many of them being Vas not Vbs.  Also keep in mind they were still testing possible range solutions for the Spit.  In September 41 for example they were still working on the testing of a fixed fuel tank under the port wing of the Spit II, that amazingly was used by three squadrons operationally.  The Spit V never had that, and the slipper tanks were a ways a way yet, although they were in development at the time.

Later reports they specify that the planes had tanks and that they were dropped or not dropped as the case may be.

I'm not sure how to prove that to you at this point.  I did note on another of the combat reports from the August 41 time frame that it mentions take off at 1745 hours and down at 1915 hours with some of the Spits having to land at closer fields then their home at Westhampnett. with the attack taking place at 1845 hours.  So clearly it was in, attack and out in a hurry, not unlike the 109s over England.

Dan/CorkyJr

[Guppy35]

First Rhubarb flown by Spits was done by 2 Spitfire II of 66 squadron flying from Biggin Hill on December 20, 1940

Trying to put my hands on my copy of Dizzy Allen's book where he talks about it, but it was over France as well.

Dan/CorkyJr

[Angus]

Out of my head, I have drop tanks in some notable use in 1942, but by then, rhubarbs were mostly over.
Also digging for the source.
Anyway, the lowlands are a bit farther regarding ocean crossing than France.

[Kurfürst]

Originally posted by Angus

So, that's what struck me. Barbi claims that the DB was about,,,what,,,,30% more fuel saving (?), so on the equal fuel load, the 109 should have ventured further than it did, - or the Spitfires should have ventured much shorter than they did.
Well, they still went where they went.

[/B]

Well the report Guppy was kind to post says Spitfires went a whole 30 miles into France.

If you want to know wheter the DB was ca.30% more 'fuel saving', you only have to check the engine cards if this is true. They say :

1940
Merlin III, ca 1050 HP, Combat : 89 imp. gallon hour (404 liter/h)
DB 601A, ca. 1050 HP, Kurzleistung : 69 imp. gallon/hour (313 liter/hour).
29% better fuel effiency for the DB.

1942
Merlin 61, 1560 HP, Combat : 130 igph, or 590 lit/hour
DB 605A, 1550 PS, Notleistung : 470 liter/hour
25% better fuel effiency for the DB.

1944
Merlin 66, +25, 1960 HP, Combat : 197 igph, or 895 lit/h
DB 605D, 1,98ata, Sondernotleistung : 650 liters/hour
37% better fuel effiencz for the DB.

Originally posted by Angus
Then to the secon phase.
I have over and over seen Barbi's statements off how quickly the Merlins got thirstier, and hence the Spitfires running on their normal 85 gallons, should have been getting shorter and shorter legs. So, time for RL stats

[/i][/B]

Like, range at 220 mph IAS econo cruise :

Bf 109 G : 725 miles on 88 gallons
Spit IXLF : 434 miles on 85 gallons

Indeed the earlier Marks of Spit were probably more fuel efficient, so I guess their range were ca. 500+ miles.
We have yet to see the documentation for the SpitI and Vs range. Considering that many Spit affiendos are watching this thread, and obviously have such data at hand, I wonder the reason why dont they post it...

What does this tell you?

The answer to the riddle promoted earlier is this:
Spitfire Mk IX, low flight up & down through clouds and fronts, 200 gallons max used, flight time 5 hrs, distance equal to east-Anglia to Berlin and back, Pilot Jeffrey Quill.
I my have some PR data to come, but, well, this is a 109 thread [/B]

Looks about right on the first glance, I have yet to find the IX range docs for ca 200 gallons. The difference is, the Spit had to carry 60% of the fuel externally to get that range, making jettisoning of the droptank a very bad idea - and the aircraft a lumbering beast burdened with a huge d/t.109s had as good range on 154 gallons, which meant they had 88 gallons internal after the they dropped 66 gallon tank, making such d/t missions practical for combat operations, unlike in the case of the Spitfire.
R-R would have to pay some attention to the fuel economy, not just being fixated on raising boost...

[Nashwan]

Like, range at 220 mph IAS econo cruise :

Bf 109 G : 725 miles on 88 gallons
Spit IXLF : 434 miles on 85 gallons

That's not maximum economy for the Spitfire.

Here're some tests of the Spit VIII, same Merlin 66 engine:



Note these figures are when fitted with a 90 gallon drop tank.

For the 109:

(Originally posted by MW, I think)

As you can see, what Isegrim is doing is taking the maximum range figures for the 109 (and he appears to be using the initial uncorrected figures as well), and comparing them with the maximum cruise speed figures for the Spitfire.

Staga, your chart also shows rather high speed cruise figures, not maximum economy figures. The manual says that maximum economy would be obtained at 1,700 rpm (which would also be at lower boost).

Note that at 2650 rpm, the Merlin 66 returned the same 55 gals/hour, drop that down to 1700 in the Spit II and you could expect around 20 gals/hr.

[Angus]

All baffling!
Well,,,,this:
"Looks about right on the first glance, I have yet to find the IX range docs for ca 200 gallons. The difference is, the Spit had to carry 60% of the fuel externally to get that range, making jettisoning of the droptank a very bad idea - and the aircraft a lumbering beast burdened with a huge d/t.109s had as good range on 154 gallons, which meant they had 88 gallons internal after the they dropped 66 gallon tank, making such d/t missions practical for combat operations, unlike in the case of the Spitfire.
R-R would have to pay some attention to the fuel economy, not just being fixated on raising boost..."

This was a test flight with a fuselage tank and a drop tank. The thing about it is that he is burning 40 gallons an hour. So, quite amazing really.
Especially in the case of a lumbering beast.....
Now, the Spit V's that finally got tanks had like 60-90 gallons external, and 85 internal. So, they are practically identical to the 109 in that manner.
So, what is unlike with the case of the Spitfire?!?!?!?!?!?!? Spit drops tank, - unpractical. 109 drops tank, practical?????

I mean, all Spits had short legs except the VIII, maybe VII, really late ones, and the PR ones. The rest from Mk V onwards used the same drop tank princip as the 109, or slipper tanks for ferrying.
And all engines like that size and tuned to the limit will just gobble up fuel like mad.
Ok, some numbers.
Spit VC goes some 650 NM's (700-750 miles) with 175 gallons, that's some 3.5 hours on cruise at 220, - if that fits you have 50 gallons an hour, or for that sake, 4.2 miles a gallon.
JFQ flight test goes with 40 gallons pro hour at low altitude, distance covered is 1100-1200 miles, so 5.5 miles pr gallons.
Note that those aircraft still have some wee bit in the tanks at landing.
Now calculate at will, but these are actual flights. The 80 gallon an hour figure seems to leave a logical margin for possible combat and so on.
85 gallons would then do to up to some 450 miles, which is actually Bruxelles and back, but with very little margin. And that's how I belive it was.
Giving the 109 the same range it should however have ventured much further than it did. London-Calais is less than 100 miles. If you want to stretch this a bit, 109's from the coast fields of France should have ventured to Birmingham, which is 200 miles.
Now, if their range was longer than the Spitfires, it would have given them some time over there as well.
Yet, 109's were sometimes forced to leave German bombers before getting to London. Ok, in cases of headwind, and the escort cruising was at uneconomical speeds.
But IMHO it always boils down to the same.
Spit and Messer have very similar ranges on the same amount of fuel.

[MiloMorai]

Well you got me Barbarossa Isegrim but you do post your home made graphs. BTW, why do leave MW off your credit list? You are using his graphs.


On range:

109E-1, E-3 handbook:

SL
max continuous(2200rpm) - 267mi, 1.05hr
max economy(1300rpm) - 404mi, 2.20hr

6km
max continuous(2400rpm) - 323mi, 1.10hr
max economy(1600rpm) - 395mi, 1.40hr

A Spitfire Ia had a range of 575mi and a combat range of 395mi. (StH)

So even at max economy for the 109, the Spit, at max continuous, had the same range.

As Naswan noted, Barbarossa Isegrim does not compare 'apples to apples' to try to support his superior German agenda.

[Angus]

Arfff, even more baffling. Nashwan's post came in when I was typing mine. Nice documents BTW.
Well, if you want to get far, just don't throttle up

Anyway, something I forgot to tell Izzy is that Spitfires did indeed venture into France on a daily basis during the Dunkirk affair.

Well, looking better at Nash's numbers, this all fits

[MiloMorai]

1944
Merlin 66, +25, 1960 HP, Combat : 197 igph, or 895 lit/h
DB 605D, 1,98ata, Sondernotleistung : 650 liters/hour
37% better fuel effiencz for the DB.

Again he forgets that MW50, at least 150 l/h, was required at 1.98.

That gives the 605D only an 11.8% advantage.

[Staga]

You do understand MW50 wasn't a fuel ?

[Kurfürst]

Originally posted by Angus
Now, the Spit V's that finally got tanks had like 60-90 gallons external, and 85 internal. So, they are practically identical to the 109 in that manner.
So, what is unlike with the case of the Spitfire?!?!?!?!?!?!? Spit drops tank, - unpractical. 109 drops tank, practical?????

[/B]

Yep, quite unpractical. The Spit IX gets ca. the same range with 85 int + 90 gallon external as the 109 on 88 internal + 66 gallon external.

Consider this. Both 109 and Spit takeoff on full internall, and with a 90/66 gallon tank.

Both fly until they empty the droptanks completely, and get just as far away from base. The 109 used up 66 gallons, the Spit 90 gallons. Now they have to return to base as well, for which they need just as much fuel, in the case they dont dogfight at high powers at all.

The 109 has 88 gallons to do this 66 gallon trip, the Spit has 85 gallons to make this 90 gallon trip. If any high power is applied, ie. fighting, even less. Consider 5 mins at full power (109 left with 80 gallons, Spit left with 72 gallons).

Only one a/c will return to base. Thats why 90 gallon tanks were FERRY mission only for the Spits, exluding the VIII, XIV etc. which had 120 gallon internal.

The rest will be added later, it appears that Nashwan is making trick again, and not using the official German figures for the 109, instead of presenting the lowest numbers again which are for 'varying conditions' as noted, and of course were cut of from the document to hide them.

He also makes a lie about not presenting the Spit on most economical cruise conditions, the data I posted is for 220 mph, the most economical speed of Spitfires. See below : "Most economical = mph. 220

None of the official British specsheets or any other test done of Merlin 66s agree with the figures NASHWAN posted, ie. offficial datacard for Spit VIII shows :



740 miles stated with 23 gallon allowance at 120 gallon (leaves 97 gallons). Mileage : 740 / 97 = 7.62 miles/gallon.
All other Spit range docs give a between milage of 5-6.5 miles/gallon.

Nashwan just wants to stick with the BEST figures for the Spit, and ignoring all official datacards. He compares that to 109G at unspecified conditions that resulted lower numbers. Can we see those conditions? Or you are selling half-truths again?

More on that later.

[Angus]

Barbi, with the miles-pro-gallon you just gave POSTED, rhubarb missions over the lowlands are very easily possible without droptanks.
With the 109's "BETTER FUEL ECONOMY", missions from the coast of France to Scotland would have been possible.
You can toss around in data debates bellybutton much as you like, that's why I looked into the actual range of missions, and there it seems to be pretty equal, if anything the 109 is getting the short end of the straw!
Then this one
"You do understand MW50 wasn't a fuel ?"
Well, it is carried, pumped into the engine together with the fuel, where it combusts/evaporates. It needs to be carried, one share of it is a burnable fluid, the other is water that turns to steam.
I'd say that qualifies

[Nashwan]

He also makes a lie about not presenting the Spit on most economical cruise conditions, the data I posted is for 220 mph, the most economical speed of Spitfires. See below : "Most economical = mph. 220

None of the official British specsheets or any other test done of Merlin 66s agree with the figures NASHWAN posted, ie. offficial datacard for Spit VIII shows :

Isegrim, read what it says, not what you want it to say.

"Cruising speed at ft 20,000
Most economical = mph 220
At maximum weak mixture power mph 360 @ 22000ft"

Further on it says:

"Range bomb load table", and gives a figure of 740 miles clean.

However, it doesn't say at what speed those range figures are achieved

You are assuming it's at most economical speed, based on the fact that it says 220mph is the most economical speed. But it also says maximum weak mixture cruise is 360 mph, and it doesn't say in the range table which cruise speed was used. It's just your assumption

Now, I'll quote to you exactly what you said in your post a long time ago when you "revealed" that the 109 had longer range than commonly quoted:

I guess I share these range tables for the Bf 109G (G-2 to be exact), since there`s so many misunderstandings about that in the literature (most books state high-speed cruise ranges only).

You are prepared to accept most 109 figures are for high speed cruise, you will not accept the same for Spitfires even when presented with the test that confirms it

That's just blinkered, and it explains why people dismiss what you have to say. You will only accept evidence that favours the 109, and any other evidence isn't refuted, it's ignored.

If you want to show the Spitfire had a lower range, present the tests to show it, which need to show range at a particular speed, like the one I've posted.

All you have posted is a Spitfire range table at an unknown speed

740 miles stated with 23 gallon allowance at 120 gallon (leaves 97 gallons). Mileage : 740 / 97 = 7.62 miles/gallon.

Which as the TEST I posted showed, can be achieved at about 280 mph.

Nowhere on the summary you've posted does it say at what speed those range figures are achieved.

[Angus]

Notice that this is a heavy Spitfire.
Lower weight will give better results.

[gwshaw]

Originally posted by Staga
You do understand MW50 wasn't a fuel ?

Do you understand that the reason the Merlin has higher fuel usage at high power is that the engine is running rich, using extra fuel to prevent detonation, same as MW50 is being used for.

DB might have riched the mixture at high power settings as well. I haven't looked into that, I'll dig out my 601/605 docs tonight and take a look. But, a port fuel injected engine isn't likely to get as much advantage from rich mixtures as a carbureted engine.

If you want a fair comparison, compare the Merlin running lean at economy settings with the DB running at economy settings. Not at the rich settings that Kurfurst likes to make comparisons at. All that proves is that running at stoichiometric mixtures is more efficient than running rich mixtures, big surprise there.

At economical settings the DB engines are going to be more fuel efficient than the Merlin, higher compression ratio and finer mixture control are going to give better efficiency. But not on the order of 25-30% better, maybe 10-15% better at best.

BTW, I am NOT a Spitfire fan, so no agenda here. Personal opinion is that the Spitfire is the most overrated fighter of the war. But I won't get into that here.

Greg Shaw

(corrected mispelling of stoichiometric)