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Supercharger setup and supercharger air intake were optimized for lower alts (Fw 190 suffered from internal air intake somewhat). Plus aerodynamic improvements on the La-7.
One has to be careful with soviet data though, Prototypes tended to be way faster than production machines.
The aerodynamic advantage for the La-7 would be 4 gun barrels chutes less. The wing area was also smaller by some 5%. The weight figures from the post #1 here are way off, loaded A-8 was 1/3rd heavier than the La-7. For a more realistic comparison, the lighter Fw-190 versions, with less armament-related drag, were making 580-590 km/h at lower altitudes, and 660 km/h at 6-7 km.
The La-7s produced in 1944, on the other hand, were barely beating 650 km/h mark; it took some time (talk 1945) to produce the serial examples that can do 670 km/h.
So - the La-7 was fast because it featured a big powerful engine installed on a small airframe, while featuring a modest weapon fuel 'fraction'.
BTW, the 'TsAGI book' charts tables tend to show many Western aircraft in an unfavorable light, better to use data from Williams' site for those.
The La-7 was still using the NACA 23000 series wing, as was the LaGG-3, La-5 and Fw-190. Laminar flow wing was introduced with La-9.
I cannot figure it out
Under 10 000ft nothing could touch this thing!
So let's compare it with say a FW-190 A8
LA-7 14 cyl 41 lt radial 1700hp vs FW-190 A8 14 cyl 41 lt radial 1700hp
LA-7 weight 3500kg vs FW-190 A8 weight 3500kg
So unless the La-7 has a huge Aerodynamic Advantage over the FW-190, which I doubt
I cannot see where this plane gets all its speed from. What am I missing here ???
I cannot figure it out
Under 10 000ft nothing could touch this thing!
So let's compare it with say a FW-190 A8
LA-7 14 cyl 41 lt radial 1700hp vs FW-190 A8 14 cyl 41 lt radial 1700hp
LA-7 weight 3500kg vs FW-190 A8 weight 3500kg
So unless the La-7 has a huge Aerodynamic Advantage over the FW-190, which I doubt
I cannot see where this plane gets all its speed from. What am I missing here ???
If that is the case that the airfoil is a 23000 series, then why do you think it was so much faster?
I thot the wing was a lot of the improvement, but if not, then how is La 7 so much faster than the La 5FN?
- Ivan.
Ome of the problems with this chart is that from late 1943 BMW started introducing various improvements to the BMW801. The result is that By June 1944 both the BMW801D2 on the Fw 190A8 and the BMW801TS of the Fw 190A9 were producing 2000hp, not 1700hp.The sea level speed was thus 360mph (nearly 580kmh) which is of course much faster than the charts indicate. The engine produced about 590kmh (365mph) on the Fw 190A5, which was still in use.
The BMW801TS had I believe slightly different supercharger settings and impellor fluid dynamics which showed up as an improvement at high altitude. The Fw 190A9/BMW801TS was set up with a supplementary fuel tank that could hold fuel, MW-50 or GM-1 depending on mission. If MW-50 was implemented it would have increased power to 2200hp. May have seen use on Bombers.
La 7 probably was fast due to a smooth wooden skinning. The Fw 190 lacked a laminar flow wing, like the P-51 or Tempest, while the Germans seem to have allowed excessive weight growth to develop in the aircraft. It was rather over gunned in my estimation with 4 x 20mm canon and 2 machine guns. I can't see the value of the MG.
The next engine for the Fw 190 was the BMW801F with 2400hp or 2600hp with MW-50, it was intended for the Fw 190A10 with an enlarged wing though I suspect it would have just gone into the A9 instead.
The power growth of the Jumo 213 was running slightly ahead of the BMW 801 or at least mass of great interest to the Luftwaffe because of its ability to work better with MW-50 with lower octane fuels. Speed of the Fw 190D13/R25 with the Jumo 213EB engine was expected to achieve 400mph at sea level and 488mph at altitude. By optimising the single stage two speed Jumo 213A as a 'bodden motor' ie sea level motor sea level speeds of 400mph were also possible and run.
I'm assuming the Fw 190A9 with BMW801F would achieve about 390-400mph at sea level given the 20% to 30% greater power and exhaust thrust.
Although the Germans were movoing to the Ta 152C and Ta 152H with their greater wing areas and fuel capacity the Fw 190D9 with the same engines was clearly going to be much faster at low altitude. They would have ended up with an armament of 3 x 20mm MG213 revolver canon which were being tested on Fw 190 at the end of the war. The outer wing gun stations would become fuel tanks.
Aren't you a bit optimistic here?
At 1.58 ATA at sea level, the 190A-8 was making about 2050 HP and reaching 359 mph.
What kind of power output would it take to hit 390 mph at SL?
- Ivan.
If that is the case that the airfoil is a 23000 series, then why do you think it was so much faster?
I thot the wing was a lot of the improvement, but if not, then how is La 7 so much faster than the La 5FN?
- Ivan.
I'm using a calculation.
Fw 190A8 at 2000hp with BMW 801D2 580kmh/360mph
Fw 190A9 at 2000hp with BMW 801TS 578kmh/359mph
The above are at a boost pressure of 1.58 or 1.65 ata or so.
The following power increase were planned:
BMW801TS 2200hp at 1.82 ata by using MW50, this is a 10% increase. The cube root of 1.1 is 1.032 so we might expect 596kmh/369mph.
This is the "A Ladder also boden motor". Its probably at 1.8 or 2 ata though. I wouldn't think the Jumo 213 was much more aerodynamic than the BMW801 which is a very small frontal area.
The Western allies had outstanding fuel. I would say Soviet fuel was fairly mediocre, about the same standard as German, which is why Russians used fuel injection on their engines as well.