OT: P-51 and Bf-109

[rustysi]

My typo hehe. 20 kft

We knew what you meant.[;)]

[rustysi]

FW 190 D still had small wings

Thought they were longer on the 'D'. I'll check my book when I get home later.

[Denniss]

Fw 190A/Bf 109G were highly comparable/competitive to allied fighters up to 20k/25k, above their engine superchargers were not able to supply sufficient air and engines lost power.
Bf 109G-14 got Water/Methanol boost for lower altitudes in mid 44, small series of high alt /AS variants were produced from early 44 on cumulating in the G-10 and K-4 of autumn 44. (initial production too small, later/higher production version too late to have effect)
Fw 190D had the same wing as A-8, critical alt for engine was similar or somewhat better than Bf 109G with standard engine but it featured a better Methanol/water boost system

[wdolson]

ORIGINAL: Dili

The advantage of P-51 over German fighters was performance at altitude. Because American bombing was at 20000kft and over. That is the major reason how war was won in the air.
Fw 190 was crap except at low level with such tiny wings, and Bf 109 was also subpar being already overweight for the tiny body, version F considered the most manageable. Speed helps but not that much when aircraft with weight increases for more power do not give good support at altitude where the air is thinner.

For Germans Ta 152 arrived too late. In crucial period of late 1943-44 they had nothing as good as Mustang or Spits, even if Spits had not enough range. They considered the Fiat G.55 the better Axis fighter by 1943 with possibility of taking bigger engines but changing it to mass production and industrial concerns and prestige meant they might as well develop a new fighter: Ta 152.

There were several factors that won the air war in Europe. The Bf-109 had the altitude performance to go head to head with the higher altitude fight, but it was lightly armed which didn't make it a great bomber killer. The FW-190 had the firepower, bit poor high altitude performance. The Daimler engines were the best high altitude engines the Germans had, but they refused to allocate any to Focke Wulf until very late in the war. They were able to do some testing with the engine mated to the FW-190 airframe, but it never saw combat.

The Germans were also hampered with 87 and 92 octane fuel while most Allied fuel was at least 100 octane.

Ultimately what won the war was the training programs used by the Allies. Both the British and Americans established training and pilot rotation programs that kept up a steady flow of trained pilots and by rotating veterans back to training commands, the vets were able to drill the green pilots in real world tactics they had actually experienced. It also meant front line pilots didn't get as worn out as Axis pilots did.

No Axis country ever established a training program that was able to produce green pilots anywhere near to par with green Allied pilots. They also tended to keep veteran pilots on the front line until they were either killed, captured, or too badly hurt to fly anymore. In late 1943 US fighter pilots noted the quality of Germans they were facing over Germany was in decline and it fell off a cliff in early 1944. The Allies were able to ramp up attrition to a point where the Germans had to fill out units with greener and greener pilots.

By late 1944 most German bomber units were converted to fighters where they were little better than the green pilots coming out of flight school. A bomber pilot has completely different skill sets from a fighter pilot and their instincts in the air that work for a bomber got a lot of them killed in a fighter. The US tried a program in the 8th AF with some B-17 pilots who reached a point where they couldn't bring themselves to command a crew anymore. Most had been through a very rough mission where men in their crew were killed or badly injured.

The USAAF started transferring these pilots to fighter units. In Zempke's book he talked about some of these bomber pilots that were assigned to the 56 FG. He said they were good technical pilots, as good as the other combat veterans, but in combat they tended to become prey rather than predator. Few of them lasted more than a few missions.

ORIGINAL: BBfanboy
Fighters did have a button to inject something into the engine that gave them a sudden boost in power, but it was very hard on the engine and very short-lived in boost. I don't recall what it was that they injected into the engine.

Water boost was common, though other things were used too.

ORIGINAL: slpatgun

Nitros oxide the same thing drag racers use. This plus turbocharger in the P-38 + P-47 and in the P-51 supercharges helped bring out the best in these fighters. Avgas sent to the Pacific was refined in the US at a higher octain , in the ETO the avgas octain was refined to a lower level. That is one of reasons the P-38 was not as successful in the ETO as the Allison engines needed the higher octain fuel .

From what I've read the fuel requirements for the Allison was the same as the Merlin. The Allison and Merlin were very similar engines and their low altitude performance was similar. What set the Merlin apart was the lightweight integrated supercharger that gave it much better high altitude performance at about the same weight. I have wondered what the P-39 would have been like with the Merlin.

What troubled the P-38 in Europe was the superchargers tended to freeze up at altitude, especially in combat settings. When Zempke transferred to a P-38 unit he ran into that in one of his first missions. The unit converted to P-51s shortly afterwards and he was taken prisoner when a war weary P-51 broke up on him when he hit some rough air. The plane broke in half at the cockpit and the entire pilot's seat broke free.

Apparently the superchargers on the P-38 could handle dry and hot, wet and hot, as well as cold and dry, but the oil tended to become thick and gel when in cold, wet air. It took Lockheed a while to figure out and fix the problem, but the P-38 had been retired from Northern Europe by the time it was.

Bill

[JeffroK]

From Bill,
The Germans were also hampered with 87 and 92 octane fuel while most Allied fuel was at least 100 octane.

One of the reasons the RAF had a slight advantage in the Battle of Britain.

[geofflambert]

If I recall correctly, and I'm getting old so bear with me, Rick Atkinson had a low opinion of the 190 in Italy and suggested that they were manned by rookies. The 109s not so much.

[Denniss]

German 87 Oktan B4 fuel was comparable to allied 100 octane fuel, german 96-100 Oktan C3 fuel comparable to allied 130 octane fuel.
Some differenes in measuring Octane + lean vs rich rating.

[LeeChard]

ORIGINAL: witpqs

ORIGINAL: BBfanboy

ORIGINAL: Chris21wen

Here I am thinking an engines something that goes vroom. Certainly informative.

Fighters did have a button to inject something into the engine that gave them a sudden boost in power, but it was very hard on the engine and very short-lived in boost. I don't recall what it was that they injected into the engine.

I think it was water injection as referred to in some of the info cited above on performance tests.

Let me add methanol to the mix.

[Denniss]

Methanol and Ethanol were just antifreeze components added to the water

[Lowpe]

Ta-152 license sold to Japan....oh my.

Japanese version
The IJAAF acquired, in April 1945, the license, schemes and technical drawings for manufacturing the Ta 152 in Japan.[3] During the last stages of the conflict in Germany, with the plight of the Japanese armed forces growing ever bleaker, a large volume of the latest aviation technology Germany had to offer was given to or bought by both the Japanese army and naval air arms in the hopes that it would stem the tide of defeats and ever increasing pressure by the superior Allied air forces.

[RangerJoe]

Fighters did have a button to inject something into the engine that gave them a sudden boost in power, but it was very hard on the engine and very short-lived in boost. I don't recall what it was that they injected into the engine.

"During WWII water/methanol injection was used by both the Allies and Axis powers to increase the output power of their supercharged aircraft engines. By spraying a fine mist of a water/methanol mixture into the intake of these large engines, gains of 350-500hp were achieved. This allowed fighters and bombers to carry heavier loads at increased speeds. . . "

http://www.alkymethinjection.com/index.html

I continues on to say that NASCAR no longer allows it as well as describing how it works. If I recall correctly, once the "war emergency boost" was used then the engine had to be rebuilt. Maybe for safety reasons but it is better than getting shot down. That could ruin your whole day.

Here is a document describing what was needed for a water injection system for the P-47:

http://wwiiaircraftperformance.org/p-47 ... 3feb44.pdf

[rustysi]

Fw 190D had the same wing as A-8,

And so it was. Never realized how short the 190 wing really was.

[Rusty1961]

The short wingspan of the 190 is what allowed it to have the best, quickest roll-rate of the European war.

[rustysi]

ORIGINAL: Rusty1961

The short wingspan of the 190 is what allowed it to have the best, quickest roll-rate of the European war.

True, but what does that have to do with the price of coffee? IOW how much does that effect its usefulness in combat. Of course other than it spinning into the dirt like a top.[:D]

[Dili]

Roll rate is important to change direction.

[crsutton]

I have always found arguing over the relative merits of WWII fighters somewhat silly. They all had their strengths when flown in the correct envelope for that specific aircraft. The P51 was a very good aircraft that had the capability to fly a very long distance. This is the key. You win modern wars by projecting air power deep into enemy airspace. This is what the Mustang did better than any other WWII production fighter. That is the reason why is was the best fighter. It had nothing to do with performance. Excellent first generation planes such as the spit and ME109 had virtually no offensive role to play in the later half of the war. They were defensive fighters and the war had moved on from the need for short ranged single purpose aircraft.

In the mid 1970's I had a BSA motorcycle. That is when the US was moving away from leaded fuel and octane ratings dropped a bit. My bike was a single cylinder machine that had a 10.1 to 1 compression ratio. I just could not get it to run well on gas from the pump. I had a five gallon jerrycan and would hike it out to the local air park with the can strapped to my seat and buy 100 octane aviation gas for it. Ran like a champ on that stuff.

[Zorch]

Octane rating was also key to plane performance. Published stats don't say what gas was used.

[witpqs]

I suggest the success of the P-51 had to do with the combination of range and performance: without the additive of range it would have been just another fighter; without the performance it would have been chewed up and spit out on those deep missions.

[anarchyintheuk]

Well, if you're going to bring a logical argument to this thread, I'll have to move on.

[AcePylut]

P51 was the best because it was the best energy fighter in the war... he who runs out of energy first, loses. Pretty simple.