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-   -   Speed graphs for Spitfire and Hurricane (http://forum.1cpublishing.eu/showthread.php?t=31450)

Kwiatek 05-08-2012 08:35 PM

Quote:

Originally Posted by Insuber (Post 422186)
Your first graph refers to the DB 601A, with some 100 hp less IIRC. Speed at s.l. matches the C-7 in-game, but the latter has a DB601N rated at 1200 hp. The second graph is just an estimate based on the "drag and power". It gives only 3-4 km/h more to the C-7 against the C-1/2 for 9% more power ... just 1% more speed ... not a great interpolation imho ... :)

Well it is more complicated that you think :)

You need to compare power curves for both 601A and 601N etc. Also i dont know what engine is used for 109 C in game. Most 110 C used Db601 engine and some used 601N but what i remember there were jabo version with bomb racks which cut some speed expecially at low alts ( with densy air). 601N had more adventage at high alts over 601A then at lower alts.

Insuber 05-08-2012 08:44 PM

Quote:

Originally Posted by Kwiatek (Post 422191)
Well it is more complicated that you think :)

You need to compare power curves for both 601A and 601N etc. Also i dont know what engine is used for 109 C in game. Most 110 C used Db601 engine and some used 601N but what i remember there were jabo version with bomb racks which cut some speed expecially at low alts ( with densy air). 601N had more adventage at high alts over 601A then at lower alts.

Eheheh I'm an engineer by education I'm more complicate than you think :)

I refer to the C-7 variant, which should be entirely equipped with the 1200 hp DB601N, three/blade propeller, rising the payload from 500 kg to 1000 kg (two 500 kg bombs).

Given that the speed / drag relationship is quadratic, and the thrust / speed is *broadly speaking* cubic, I doubt that 9% more power gives only <1% more speed. But I can be wrong ... :D

Kwiatek 05-08-2012 09:27 PM

You have to note that from calculated speed graph for different 110 C variants yellow curve is for 601N 30-minut engine power and grey curve is for 601A 5-minut emergency power :)

Insuber 05-08-2012 09:37 PM

Quote:

Originally Posted by Kwiatek (Post 422233)
You have to note that from calculated speed graph for different 110 C variants yellow curve is for 601N 30-minut engine power and grey curve is for 601A 5-minut emergency power :)

Then I notice also that the first graph, taken from the 110 HandBuch, which should be the DB601A at normal boost, shows the same performance for the C-1 of the grey curve in the second graph, which is the DB601A with emergency power. I see another contradiction here of the interpolated curves, don't you think so?

Kwiatek 05-08-2012 10:21 PM

First graph from handbuch show speed at 1.3 Ata power - 5 minutes emergency but with old supercharger ( 4.0 km).

Blue and black line in second graph are for 30 minut power - 1.23 Ata. Grey line in second graph is for 1.3 Ata - 5 minutes emergency power but with new supercharger ( 4.5 km).

Worth to looke here:

http://www.ww2aircraft.net/forum/avi...ces-11171.html

and here:

http://www.ww2aircraft.net/forum/avi...nce-16139.html

As always devil is in details :P

Insuber 05-08-2012 10:27 PM

Ok thanks! The first graph had no details, so the devil was well hidden ... :-)


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