Gold-Clash

[FLYBOYJ]

Originally Posted by Soren

No no no ! They were perfectly capable of handling 100 octane 150 grade fuel. However I understand your thought, as its a rather steep increase in octane and fuel-grade.

Well with that aside, and the data from thise sites, I think we know which engine wins on power!

[Soren]

Originally Posted by FLYBOYJ

Well with that aside, and the data from thise sites, I think we know which engine wins on power!

Definitely !

[FLYBOYJ]

Originally Posted by Soren

Definitely !

[wmaxt]

Higher Octane reduces the tendency of a fuel to detonate. Higher grade fuel will not hurt an engine and Might produce more power but not always especialy if nothing else changes. Often it will alow the same power with better fuel efficency. Generaly it will allow more boost and that will produce more power.

I have a Super Charged T-bird and better fuel helped both. The same can be expected from a Super Charged aircraft engine.

wmaxt

[FLYBOYJ]

Originally Posted by wmaxt

Higher Octane reduces the tendency of a fuel to detonate.

Not always, I would agree if we were talking about a high comperssion engine, 10/12 to 1 compression ratios or large piston engines (radials). The Merlin and Damlier Benz were talking about aircraft engines were talking about carried about a 7 to 1 compression ratio, if that. Putting a super high octane fuel in in these engines there under certain conditions would be like lighting a cherry bomb on every power stroke. I think about 100 octane is as high you would want to risk without doing damage after a period of time, although I know that up to 130 octane (purple) was run in P-51s.

Also, you can't compare an automotive turobcharged engine in this matter. Automotive engines are designed to be run at varible RPM and operate at a constant atmosperic ambient temperature. Aircraft engines are designed to carry a relitively constant high RPM at higher operating temps.

[KraziKanuK]

Here is a link to a PDF file for DB605 performance, http://mitglied.lycos.de/luftwaffe1/..._varianten.pdf

German C3 fuel was roughly equivelant to Allied 100/150 fuel.

Also note that MW50 was required to achieve the higher power output.

The MK108 was not the predominate weapon in the 109 til after mid 1944.

By Olivier Lefebvre who is a well known 109 expert

G-6/U4
Produced 1943 : 181
01/1944 : 119
02/1944 : 51
03/1944 : 303
04/1944 : 404
05/1944 : 118
06/1944 : 144
07/1944 : 240
08/1944 : 49
09/1944 : 55
10/1944 : 14

G-14/U4
08/1944 : 59
09/1944 : 32
10/1944 : 228
11/1944 : 118
12/1944 : ????, 56
01/1945 : 11, 47
02/1945 : 2

G-10/U4
12/1944 : ???, 62
01/1945 : 129, 79
02/1945 : 132
03/1945 : 95

(Red numbers are coming from someone who went to the Freibrg archives and sent me the details of 109 productions from the C-Amts reports. Black number for 01/45 is coming from japo book)
We can see some discrepencies in here....

And another post from Oliver's site by Pirx,

These figures are surprisingly low... if I add them up, the result is:
Sum G-6 = 1678, which would be 14% out of the ca.12.000 overall
Sum G-14 = 448, which would be 8% out of the ca.5.500 overall
Sum G-10 = 129, which would be 8% out of the ca.2.600 overall
As the December figures miss, let's double the percentages of G-14. For the G-10, I use the precentage given in the plans in Prien&Rodeike, which leads to 55%

-->
Sum G-6/U4 = 1678, which would be 14% out of the ca.12.000 produced
Sum G-14/U4= 900, which would be 17% out of the ca.5.500 produced
Sum G-10/U4= 3288, which would be 55% out of the ca. 5.955 planned

Roughly <20%, for G-6 & G-14 in the 2nd half of 1944 and 55% of the G-10...

Not included is the K-4 for which maybe 8-900 were built in 1944.

[FLYBOYJ]

Good Show KK!

[KraziKanuK]

Some links on German Avgas

http://www.fischer-tropsch.org/prima...145_45_toc.htm
http://www.fischer-tropsch.org/Tom%2...0Item%206A.pdf

[FLYBOYJ]

Originally Posted by FLYBOYJ

Not always, I would agree if we were talking about a high compression engine, 9/10 to 1 compression ratios or large piston surface area engines (radials). The Merlin and Damlier Benz engines we're talking about carried about a 7 to 1 compression ratio, if that. Putting a super high octane fuel in in these engines there under certain conditions would be like lighting a cherry bomb on every power stroke. I think about 100 octane is as high you would want to risk without doing damage after a period of time, although I know that up to 130 octane (purple) was run in P-51s. High octane and over boosting is also a dangerous combination. Water injection helped overcome this. Here's a great site about aircraft engines, fuels and supercharging: http://www.pilotfriend.com/aircraft%...elopment.ht m

Also, you can't compare an automotive turbocharged engine in this matter. Automotive engines are designed to be run at variable RPM and operate at a relatively constant ambient temperatures. Aircraft engines are designed to carry a relatively constant high RPM at higher operating temps.

[Soren]

Nice sites Krazi.

From the site: The C-3 grade corresponded roughly to the U. S. grade 130 gasoline, although the octane number of C-3 was specified to be only 95 and its lean mixture performance was somewhat poorer.

The C-3 fuel was roughly equal to U.S. 100 octane/130 grade fuel.

[Udet]

I do not hesitate to appoint the Bf 109 G10 as the winner.

Right, there were fighters of the version fitted with field conversion kits but there were many reaching service right like the one shown in the photo.

I happen to know men who flew this particular model with success against the enemy during the tough months of 1945.

The 30mm cannon in the nose, whatever the muzzle velocity, was not -at all- a "disadvantage" when in combat against the six .50 cal Mustang guns.

Right, the Mustangs armament was good enough to destroy a Bf109...but what makes you think the Bf109 G-10 armament was "less efficient" at getting Mustangs burnt beyond recognition?

Just like in the G-6 version, there were G-10/R6 fighters, fitted with one 2cm cannon under each wing in a gondola.

I have guncamera footage of Bf109s fitted with the underwing gondola cannons getting chased by USAAF fighters. Before having such material in my possession, i was acquainted with the typical song saying the underwing gondolas "implied a dramatic decline in the performance of the fighter making it an easy prey for enemy fighters".

After seeing my material i would not be so sure on the veracity of that typical song the allies enjoy singing so much.

In most of those guncamera shots, the gondola fitted Bf109s are being tailed by the foe. I was surprised to discover that from the rear, the gondolas under the wings look real small and slender and not that protruding.

I am not dispute a cleaner wing is better. And that 2 kilograms are heavier than 1.5 kilograms (the extra weight). My point is i do believe the allies have exaggerated on the consequences of having the fighters fitted with underwing gondolas.

Also i was surprised to see the Bf109 pilots attempted evasive action and you could see everything but a fighter "uncapable of manouvering": the 109s turned and climbed like hell. In fact, in some of the shots the USAAF pilots flatly missed the gondola Messerschmitts who managed to find their "out".

It appears to me the rail fitted Typhoons of the RAF (to have it armed with non-guided rockets) suffered more than the gondola fitted Gustav.

[KraziKanuK]

LOL Udet, I know one fanatical Luft luver/British hater who crys the blues because people use the British tested gondola G6 as an example of a typical G-6. He claims this a/c is not typical of 'clean' winged G-6's performance since the gondolas cause a drastic reduction in a/c performance.

You Luftluvers should get your stories straightened out.

[delcyros]

There can be no doubt that gondolas as well as drop tenks reduce the performance considerably. However, the quality of ´this change is matter of debate. The Mustang tested with drop tanks suffered bad handling as well as reduced performances (excepting the dive). But what counts more are the negative effects in the ability of the plane to keep it´s energy. No matter if a Luftwaffe plane or a USAAF or anything else.
I think we should also consider the probable conditions of engagement. Quantity has it´s own quality. By that the Luftwaffe had a nominal number advantage up to early january 45 but was unable (better unwilling, since Gallend tried but was not allowed in the last moment to do so) to concentrate it´s efforts on a certain region with enough planes to deal with escorts and bombers, resulting in a real quantity advantage of the Mustangs. The P-51 enjoied also a better gunsight and some early G-suits late in the war as well as a generally more careful pilots training.
The Luftwaffe has the advantage to fight over their own terretory and to choose where they wanted to fight and where not.

[Soren]

Udet the Gondola's lowered maneuverability considderably ! This is also quoted by many LW pilots, aswell as Finnish pilots.

Heinrich Beauvais especially noted the rapid decrease in turning performance, looping and climbing when fitted with gondola's.

Also what makes you think the Gondola's weighed only 2kg ? They weighed considderably more than that ! (And thats not accounting for the extra ammunition required)

[DAVIDICUS]

"Just like in the G-6 version, there were G-10/R6 fighters, fitted with one 2cm cannon under each wing in a gondola. "

This "Gold-Clash" involves a G-10 outfitted with one Mk. 108 and two Mk. 131's. Hence the issue with the armamant specific to that gun configuration.

"[b]ut what makes you think the Bf109 G-10 armament was "less efficient" at getting Mustangs burnt beyond recognition? "

I have already outlined my reasons previously in this post. Long range and deflection shots against a small twisting and turning foe with a single, slow firing, slow velocity gun would be very difficult. Complicating this issue is the fact that he 13mm 131's have radically different trajectories making their combined use with the Mk. 108 unfeasible under those circumstances.

According to Soren though, this was not a problem as evidenced by this configuration being the preferred set up for fighter to fighter engagements. I frankly find that hard to believe, but assuming it is true, my assumptions underlying my thesis are flawed.