Acceleration comparisons

[gaunt1]

Originally Posted by majorfailure

I really don't see where your 55% come from, from il2compare I get climb at sea level La-5F: 17.5 (21.5 with boost) and La-5FN 21.2 (25.3), which both is around 20% better acceleration for La-5FN

Please... Check the ACCELERATION chart made by HORSEBACK. (page 6, post # 44) It clearly shows the insane advantage of the FN over the F. For example, 270 to 500 km/h takes 56 seconds for F, and 36 seconds for FN. Thats 55.5% better performance.

[FC99]

Originally Posted by gaunt1

Please... Check the ACCELERATION chart made by HORSEBACK. (page 6, post # 44) It clearly shows the insane advantage of the FN over the F. For example, 270 to 500 km/h takes 56 seconds for F, and 36 seconds for FN. Thats 55.5% better performance.

JtD already pointed at something important in post #100 of this thread,I'll repeat it again.

Originally Posted by MaxGunz

La5FN to La5 Ps ratios?
At 280 kph, 122%. At 400 kph, 133%. At 500 kph, 350%.

[MaxGunz]

Originally Posted by gaunt1

Please... Check the ACCELERATION chart made by HORSEBACK. (page 6, post # 44) It clearly shows the insane advantage of the FN over the F. For example, 270 to 500 km/h takes 56 seconds for F, and 36 seconds for FN. Thats 55.5% better performance.

Does someone have to walk through how acceleration, distance and time relate?

I can't promise you'll get it. If you're lost at ratios then squares and roots will look like tricks.

Sorry but I stuck with math for years to understand how I do, what I do. It's not an insane advantage that you're seeing. It's to be expected and understood and have tactics made on.

Last time I felt like this the 'issue' was over dive accelerations and the inability to dive beyond guns range from 100 m or less in a few seconds.

[majorfailure]

Originally Posted by gaunt1

Please... Check the ACCELERATION chart made by HORSEBACK. (page 6, post # 44) It clearly shows the insane advantage of the FN over the F. For example, 270 to 500 km/h takes 56 seconds for F, and 36 seconds for FN. Thats 55.5% better performance.

You are making the mistake of assuming acceleration to be constant, but it changes with speed, and changes differently with each plane.
Use the ROC vs speed diagram in Il2compare and I bet it will fit the data okay.
Very rough comparison: La5FN flies 420kph at half time(18s), so lets compare acceleration at 420 to La-5F, ~15m/s to ~10m/s, so 50% better is okay.

[horseback]

Originally Posted by gaunt1

Please... Check the ACCELERATION chart made by HORSEBACK. (page 6, post # 44) It clearly shows the insane advantage of the FN over the F. For example, 270 to 500 km/h takes 56 seconds for F, and 36 seconds for FN. Thats 55.5% better performance.

I'd say that it's more like 55.5% better time. The lead one develops through each 10kph interval is added to the next one, and the next, sort of like compounded interest. If you have a power advantage of 20%, it is applied in each interval, and that advantage increases with every subsequent interval.

Acceleration is usually expressed in terms of both time and distance: some many meters per second per second (or per second squared). It is an ongoing process, and the primary limitation is air resistance, or drag, which increases as a cube of the velocity, if I remember correctly. In any case, you need exponentially more power to overcome drag as speed increases, which is why my charts depict curves instead of straight lines.

cheers

horseback

[MaxGunz]

There's 2 main kinds of drag operating here. A total drag graph is U shaped.

At lower speed **for the plane with wing loading a big factor** is induced drag. This is a real killer for the FW's until maybe 340-360 kph.

From middle speed on up, parasite drag goes up by squares, twice the speed is 4x the parasite drag even as induced drag falls due to lift squaring with increased speed allowing the nose to drop while keeping level flight. (trim)

Ps is excess thrust, total thrust minus drag. The faster a prop plane goes, the less thrust it has which is where the steepness of Ps curve at high speed sets in. It's not a constant minus the drag U but a downward slanted line minus the drag U.

I just had a look at La5F vs La5FN (IL2C 4.07m) and the La5F Ps curve looks the same as the La5 Ps curve when switching back and forth.

What's the difference between a Spit VB and a Spit LFVB besides supercharger?

At 240 kph, Spit VB = 13.5 -- Spit LFVB = 17.3 --- 128%
At 320 kph, Spit VB = 10.5 -- Spit LFVB = 15.5 --- 148%
At 400 kph, Spit VB = 3.8 -- Spit LFVB = 9.9 ------ 260%
At 430 kph, Spit VB = 0 -- Spit LFVB = 7 ----------- PWNED!
What % longer will the Spit VB take to reach 440 kph in level flight? If 50% longer is insane then what is forever?

[horseback]

What's the difference between a Spit VB and a Spit LFVB besides supercharger?

At 240 kph, Spit VB = 13.5 -- Spit LFVB = 17.3 --- 128%
At 320 kph, Spit VB = 10.5 -- Spit LFVB = 15.5 --- 148%
At 400 kph, Spit VB = 3.8 -- Spit LFVB = 9.9 ------ 260%
At 430 kph, Spit VB = 0 -- Spit LFVB = 7 ----------- PWNED!
What % longer will the Spit VB take to reach 440 kph in level flight? If 50% longer is insane then what is forever?

Depends on the flavor of Mk Vb we're talking about; the early ('41) version has a bit less 'oomph' over all, the late ('42) version is essentially the same as the '43 clipped wing version with slightly less wing loading, and the Merlin 46 type has a different engine which is (I assume) optimized for high-medium alts.

Minor variations may be ascribed to my faults as a test pilot, or arbitrary decisions about averaging out the results of the four runs for a given type.

cheers

horseback

[MaxGunz]

Those are the ones in IL2Compare 4.07m, the last IL2C I have.

[IceFire]

Originally Posted by MaxGunz

Those are the ones in IL2Compare 4.07m, the last IL2C I have.

There's a 4.11 IL2 Compare kicking around. Haven't seen a 4.12 yet...

[Monty_Thrud]

Originally Posted by IceFire

There's a 4.11 IL2 Compare kicking around. Haven't seen a 4.12 yet...

http://forum.1cpublishing.eu/showthread.php?t=29744

Scroll down for 4.11