190A5 vs 190A8 engine Performance

[Guppy35]

You guys might want to be careful or the Spit guys are going to start the higher octane fuel/ +25 boost stuff again

[Ardy123]

Ardy you posted that there is a 1% difference in WEP power and the A-8 is 900 lbs heavier. Does that answer your original performance question comparing the A-5 and A-8?

not quite because the ATA numbers don't match if they are the exact same engine, why would the A8 support a higher manifold pressure in AH? This seams to imply that in AH, the A8 is in fact outputting more power, which doesn't fall in line with the Wikipedia article, unless the A5 is modeled to the non-wep setting mentioned in Wikipedia or Wikipedia is incorrect.

1.42 ata figure (1730PS?!?!) seems to fit the HTC's speed chart with 410mph tops for A5, so if A8 is modeled with 1.58ata the power loading figures are very near but still on A8's favor. The better power loading obviously does not compensate for the higher wingloading at altitude so the A8 is still slightly slower at alt. Although the figure of 410mph at 20k for A5 includes deck speed of 348mph on deck, where as HTC A5 is slower for some reason, even if it should be nearly as fast as A8 on the deck?  
http://www.wwiiaircraftperformance.org/fw190/fw190a5.html
-C+

Based on the posts above I've revised the power/to weight ratios

If the A8 is outputing 1.58ata and its in accordence to the chart....

FW 190-A5
1.42ata 1730PS =  1706.30hp
8802lb /  1706.30hp = 5.159 lb/hp

FW 190-A8
1.58ata = 2050ps =  2021.92hp
9702lb / 2021.92hp = 4.79040 lb/hp

Despite the added weight the power to weight ratio between the A5 and A8 IMPROVED! This is what seems odd because in the game A5 seems to have the edge on acceleration, climb and top speed.




OR is it that although the ata numbers appear to support the 2050ps, the actual output as someone else stated is 1800ps 'low blower' setting despite having 1.58ata as the manifold pressure?

[Wmaker]

You guys might want to be careful or the Spit guys are going to start the higher octane fuel/ +25 boost stuff again

...or you could leave the irrelevancies out of this thread?

[Wmaker]

Despite the added weight the power to weight ratio between the A5 and A8 IMPROVED! This is what seems odd because in the game A5 seems to have the edge on acceleration, climb and top speed.

There are many factors at play here. One is definately the differences between individual tested aircraft and the fact that some of the data which is in question here is probably calculated.

This is the performance data that matches with AH's A-8's performance:

As you can see, the powersettings match and one engine that the data sheet refers to even happens to be the engine I posted the power curves on (Sr.Nr. 9-801:5401 dated 10.7.42). The other engine they refer to is 9-801:10292 dated 15.3.44 (if I read it right). Since two different engines are mentioned, it looks like the values could be calculated based on previous engine testing. Off course I could be wrong aswell.

A slightly better performing A-8 can be found from here:

As you can see, only 7mph difference to the speed on the deck and about 0,5m/s difference in the initial climb rate. This kind of differences are to be expected between individual aircraft.

[Ardy123]

hmmm... thats interesting so despite the improvement in the power-to-weight ratio, there was not much of an improvement to the performance. I just noticed that both of the sheets you posted state a 1.42 ata not the 1.58 that we see in ah.

[hitech]

Ardy many times adding power does not increase best climb rates unless a prop change also occurred.

The extra power still shows up in speeds and other aspects of flight at speeds higher then best climb speed. I have not looked at these two planes specifically, but many times they can not get enough prop for improving climb.

HiTech

[Guppy35]

...or you could leave the irrelevancies out of this thread?

You clearly missed the point and the smile.  No worries though

[Ardy123]

Ardy many times adding power does not increase best climb rates unless a prop change also occurred.

The extra power still shows up in speeds and other aspects of flight at speeds higher then best climb speed. I have not looked at these two planes specifically, but many times they can not get enough prop for improving climb.

HiTech

HiTech,
Thank you for your input. I believe the prop did change, at least according to the Wikipedia article, it states...

'From the A-8 on Fw 190s could be fitted with a new paddle-bladed wooden propeller, easily identified by its wide blades with curved tips.'

http://en.wikipedia.org/wiki/Focke-Wulf_Fw_190

[Wmaker]

hmmm... thats interesting so despite the improvement in the power-to-weight ratio, there was not much of an improvement to the performance. I just noticed that both of the sheets you posted state a 1.42 ata not the 1.58 that we see in ah.

The darkened limits of the curve are achieved with the WEP-setting (1.58ata low blower, 1.65ata with the high blower). As HT says, the prop's efficiency curve plays a big part here.

[Ardy123]

The darkened limits of the curve are achieved with the WEP-setting (1.58ata low blower, 1.65ata with the high blower). As HT says, the prop's efficiency curve plays a big part here.

lol, Honestly, I can't read the darkened area, or most of the sheet where the graph paper lines are...

[Wmaker]

lol, Honestly, I can't read the darkened area, or most of the sheet where the graph paper lines are...

Ok.

Here's a bit more readable version:

[Ardy123]

interesting... so only in specific ranges did it make a difference. As pointed out, the A8 could be fitted with a wider prop. I wonder how common that was and if it created a noticable impact.  

[Wmaker]

interesting... so only in specific ranges did it make a difference. As pointed out, the A8 could be fitted with a wider prop. I wonder how common that was and if it created a noticable impact.  

Yep the additional power could be maintained until the air got too thin for the first supercharger gear to maintain it (critical alt). After that, the power drops linearily until the next gear is engaged and so on.

About the prop...

I've understood that the vast majority of the A-8s had the 3,3m VDM 9-12176A prop which is the same prop as in the A-5. There are some documents that talk about the 9-12153B and 9-12157H3. The 9-12157H3 was wooden 3,5m diameter prop which was intended for the A-9 but even most of the A-9s were supposedly equipped with the regular A-8's 3,3m VDM 9-12176A prop. So all in all, it's the same prop as in the A-5 as far as I know. There might have been some trials with the larger props in the A-8 but I'm almost positive that none were so produced, and if they were, the numbers must be minimal.

[Baumer]

Ok, here's my take on the engine configuration of the Fw190A-8 in Aces High;

First, looking at "Part 7 Engine operating and fuel supply system"  of the manual has this for the emergency power system.



Given that the Fw 190A-8 has 10 minutes of WEP in Aces High it seems likely that we have this system installed in game.





Given that we can get power settings that match this description, it adds to the likely hood that the emergency power system is modeled.



Now here is some more pertinent information that's contained in a technical description of the Fw190A-8.



Looking at the aux fuel paragraph it's clear that almost all A-8s were planned to be produced with the auxiliary fuel tank.



This makes it clear that the emergency power system was to installed on all Fw190A-8's.


Testing in Aces High produces the RPM and ATA settings that are outlined in this document so I'm very confident that it is modeled, and modeled correctly (in my opinion).

[Ardy123]

Very interesting so as pointed out before the only thing that is different is the ata 1.65 with the super charger in high gear or 'high blower' as mentioned before. Cool find, very interesting, thank you.