RAM -> RE: Japan's scientists suck (9/13/2006 2:58:46 AM)
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hi, wdolson. quote:
The Germans were also using fuel injection before the US or Britain. not sure if that is completely true. Yep, the DB used direct fuel injection while the Merlin didn't. But the R&R decision not to fit fuel injection in the Merlin had to do with the ability to achieve slightly higher manifold pressures using carburattors ratern than direct injection (or so I read somewhere). Noone thought about negative-G problems at that moment...but they had the means to design the engine with direct fuel injection. quote:
The western Allies were using MW and GM too. That's true, but they did on a much smaller scale than the germans. quote:
I was thinking of the DB603, which was comparable to the Merlin in output. The DB603 compared even better against the Merlin. Not a surprise, for it was a powerplant on a very different scale: it had more displacement than the DB605 did (and was heavier as a result, too). And the DB605 already had a displacement comparable to that of the R&R Griffon. The 603 was the "big brother" of the main DB600 series (not counting the disastrous DB606 or 610, wich were in fact twin engines) By the end of WW2 DB603s achieved power outputs roughly similar to those of the Jumo213, and was better than the Jumo at altitude. We're talking about 2200-to-2300hp outputs here. And the germans expected latter DB603 versions to reach outputs of 2600hp as they believed the engine had room for improvements... quote:
Maybe in Europe. My father was a combat photographer and flew with bomber groups all over the Pacific. He said that 140 octane for even B-25s was normal by mid-1944. That's surprising ,and a good bit of info...I always thought the frontline fuel used by the allied to be 100/130 octane fuels. 140 is certainly high. Maybe on the very latest months that fuel was more widely used. The V1-chasing squadrons used 150 octane avgas. BTW and out of curiosity, which was the lean octane rating of the 140 octane allied fuel?...I know the 130 octane fuel had a lean rating of 100, but the 140 one, I have no clue... anyway, remember that aviation fuel quality depended on more variables than just octanage. The oil the fuel was refined from defined a lot of characteristics the combustible would have. The best fuel for aviation gasoline was the one coming from Indonesia (or so was found during the schneider races) while Americans had a problem at first refining gasoline from their own oil production (those were solved later by changing the way the oil was refined). German fuel came from coal. This means the german avgas was the "Dirtiest" possible, the quality was quite low. In fact the german engines were mostly built to be able to run this kind of very "dirty" fuel. For instance, the BMW801 aboard the Fw190A3 the British captured in 1942 was ruined after the aircraft was tested with their own fuel (which was significantly better!!!)...after a few hours of testing the plugs of the engine were found to be faulty when they had been faultless on a prior exam of the engine unit... quote:
The only way Germany survived the loss of Soviet oil was by demechanizing the army. After 1941, the supply units started converting back to horse drawn wagons. By 1943, trucks were mostly out of use for supply purposes except with elite units like the SS and in some units in Italy. By 1944, virtually the entire army used horse drawn wagons. The oil shortage was real and critical throughout the war. Never said otherwise. I said Germany had problems with oil supply, that's undeniable. What I said is that the assessment of Hitler about Germany needing so desperately the caucasus oil was a gross exageration. Germany was able to fight on for 2 years after he made those comments, on a full scale. The problem could've been much lesser had Germany moved to a proper war economy since 1940, something germany never did. But anyway, fuel shortages existed but they were never critical until the 8th AF started hitting german oil refineries. After that, everything fell down. Before that, Germany could go on fighting using its own oil sources. So, the Caucasus was not indispensable for german's war economy. First because such a war economy never existed, and second, because that war economy could've worked without that oil...and in fact, it did. The gradual reduction of trucks within the army may have had something to do with fuel, but not everything, and not by far. German's own vehicle industry coudln't supply the ammount of trucks the Wehrmatch needed. First of all, the Wehrmatch was never a fully motorized army. Only a relatively small fragment of it received the organic transport it was intended to receive. Many of the infantry divisions never were motorized at any apreciable scale,for instance. Then, remember that in 1942 around a 65% of the trucks used by the germans came from captured stocks!!!!!. When those trucks started to be lost in battle, by exhaustion, or because no replacement parts were available (being of foreign origin), german industry couldn't replace them- and so many german formations had to return to horse-and-wagon transports, leaving the Panzerwaffe and the Waffen-SS as the only really mecanized formations within the Wehrmacht. But while I can accept that indeed this was an advantage when fuel was a scarce resource, I don't really think the whole matter was forced by lack of fuel, but because an inherent lack of production which couldn't cope with the army needs. quote:
I was thinking about reliability and maintanability too. American radials were very reliable. The early Fw-190s were a maintenance nightmare. The Germans tended to over engineer things. Hmm, don't confuse the plane with the engine. The BMW801 was a perfectly working powerplant by 1940. Static testing proved it. The problem with the 190 installation was never the engine, it was the plane. To prove it is the fact that while the Fw190 received many modifications to end with the overheating troubles, the BMW801C received none. The engine fitted in a Fw190A2 was the same fitted in a Fw190A0. The A0 had terrible overheating problems, the A2 did not. That Focke-Wulf had serious trouble when fitting it into its new fighter says little about the BMW801 reliability. The problem with the 801 in the 190 was that the 190 had been designed for a totally different powerplant (the eighteen cylinder BMW139), the new engine refrigeration needs were much higher, and the design was unable to cope with the new situation until new ways to refrigerate the aft row of cylinders were found (if you see the bulges protruding from the sides of the Fw190A's cowling, those were put there just because of that reason) But the powerplant itself, was found to be highly reliable, able to absorb heavy battle damage and return home, and sturdy as a rock. From 1944 onwards the quality of the engines fell down because of poor production standards result of the mass-production needs of the Germans, which made the quality go down in everything they built, but for 1940-1941 it was a superb powerplant, in my opinion the most advanced one in the world, and certainly the best radial of it's time.
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