Fw190A-8: acceleration?

[Crumpp]

Your comparing take off weight to take off weight.

Remember the parameters are:

The United States Forces will commonly use empty service weight to compare realitive weight creep. Using that yardstick, the FW-190A8 gains 54Kg over the FW-190A5. The rest of the "weight gain" is consumables.

 

Rüstgewicht

Is equal to empty service weight.

FW-190A5
Fluggewicht - 4088Kg

FW-190A8
Fluggewicht - 4272Kg
with 115lt tank - 4392Kg

Dunno where you got 166kg from

4272kg - 4088kg = 184kg
4392kg - 4088kg = 304kg

I think I switched the FW-190A5 with FW-190A5 with ETC 501 weights. It is a 126 KG difference however.

All the best,

Crumpp

[JAWS2003]

One question. What was the power of the engine on A8?

[justin_g]

Comparing empty equipped weights isn't going to be very reliable when you try to relate that to the performance of the aircraft at flying weights... which was the issue in question I believe.

Saying there should only be 126kg difference between A-5 and A-8 could be confusing when people are looking at the HTC figures which are for an underweight G-3(A-5) and a fully loaded A-8. FOR EXAMPLE:

So, on HTC's page for the A-5 they list it at 8586lbs (3893kg's). If the FIGHTER variant of the A-8 is only 366lbs (166 kg) heavier than the A-5 it should weigh 8949lbs (4059kg) but it doesnt, it is listed as 9682lbs (4391kg). Thats 733lbs (332kg) more than the difference between the fighter versions of the A-5 and A-8 should be. The actual difference in the A-5 and A-8 in AH (if the HTC pages are actually the modeled weights) is not 366lbs (166kg) like its supposed to be its actually 1096lbs (497kg)!! Where did the extra 733 pounds come from?

[niklas]

Originally posted by Crumpp


That is a mistranslation.  It happens when dealing with German and I have seen native speakers argue over the meanings of the some of the idiomatic or specific jargon.

In the original German, it is a normal finish for a Luftwaffe aircraft.

Crumpp

Na gut dann auf Deutsch:

Zitat:
A5:
Oberfläche: Gespachtelt u. poliert

A6:
"Oberfläche:  Gespachtelt + Glattanstrich (nicht  poliert!) "

"Ab A6 soll aus Fertigungsgründen auf polierte Oberfläche verzichtet werden"

A8:
"Oberfläche:  Gespachtelt + Glattanstrich (nicht  poliert!) "

Obviously they thought the A8 could be polished by the mechanics . This means if it was well prepared it could be at least as fast as a A5 with same power.

Gruss
niklas

[Crumpp]

Comparing empty equipped weights isn't going to be very reliable when you try to relate that to the performance of the aircraft at flying weights... which was the issue in question I believe.

Sure, I was not trying to initiate a weight comparision thread.  I was only pointing out that different countries have differenct standards for comparison.  Many of the US designs are compared at empty weight and many of their performance graphs are adjusted to combat weight.

Focke Wulf generally used take off weight and adjusted all performance curves to reflect this weight.  It's a conservative method and ensures you will not recieve as many performance complaints from the end users.

One question. What was the power of the engine on A8?

2100PS or 2050hp at 1st gear supercharger FTH using 1.58ata@2700U/min.  The FW-190A8 also had a more efficient propellers in service.

All the best,

Crumpp

[F4UDOA]

Many of the US designs are compared at empty weight and many of their performance graphs are adjusted to combat weight.

Where have you seen this?

Actually the British test are backwards, they take off at gross weight and then list the perofrmance at 95% of the gross.  So whatever the performance says it was actually 5% heavier during the test.

Also the FW190's are not the only A/C modeled with drop tank racks and bomb pylons attached. There are a few allied ones that have them in all flight conditions regardless of loadout.

[Crumpp]

Where have you seen this?

In several reports F4UDOA.  Grumman especially.

You can start another thread if you would to discuss it.  Please leave this one on subject.

gross weight and then list the perofrmance at 95% of the gross.

Sounds like they are trying to match performance right at take off then.

All the best,

Crumpp

[HoHun]

Hi F4UDOA,

>Actually the British test are backwards, they take off at gross weight and then list the perofrmance at 95% of the gross.  So whatever the performance says it was actually 5% heavier during the test.

Hm, the truth is that the weight at take-off might have been 100%, but it decreased during the test flight due to the fuel being burnt. Accordingly, most of the tests were made at a lighter weight than 95% of the take-off weight.

However, that's not a problem since by recording fuel states and engine run times for each of the test stages and then applying some math to the test results, it's possible to calculate the data that would have resulted from flying at a fixed reference weight. (Which of course, is physically impossible :-)

Choosing 100% take-off weight as reference is just as valid as choosing 95%, it's just a factor to stay aware of when comparing different tests.

Regards,

Henning (HoHun)

[Widewing]

Originally posted by HoHun
Choosing 100% take-off weight as reference is just as valid as choosing 95%, it's just a factor to stay aware of when comparing different tests.

Indeed, just as we must do the same for testing planes in the game. However, we have the advantage of being able to set the fuel burn to zero.

Here's some acceleration data for the AH2 Fw 190A-8, A-5 and some contemporaries.

Measuring acceleration from 200 mph TAS to 300 mph TAS at sea level. Time recorded in seconds. Fuel loads adjusted for similar range.

190A-8 100% internal fuel, four MG 151 package....
With external fuel tank: 52.06 seconds
With rack only: 44.53 seconds
Clean airframe: 42.63 seconds

190A-5 100% internal fuel, two MG 151, 2 FF cannon
With external fuel tank: 56.78 seconds
with rack only: 47.97 seconds
Clean airframe: 44.82 seconds

P-38J 75% internal fuel
With two external tanks: 53.02 seconds
With pylons only: 41.26 seconds

Spitfire Mk.VIII, 100% internal fuel
With slipper tank: 41.38 seconds
Clean airframe: 38.15 seconds

F4U-1, 100% internal fuel
With external tank: 56.12 seconds
Clean airframe: 45.69 seconds

As you can see, the bomb/tank rack has a significant effect not only on speed, but upon acceleration as well. Since we do not have American aircraft without integral underwing pylons/shackles, we cannot determine their effect on performance.

Note that 190A-8 accelerates faster than the 190A-5 when configured in a similar fashion.

My regards,

Widewing

[F4UDOA]

Crummp,

No need to start another thread, just responding to the generalization.

If you look at AAF and compare the graphs to manufactures data you see a difference in some and not in others. This tells me that the AAF is being honest about their testing and reporting.

At the end of the day I trust the guys in uniform because it is there butts on the line.

[Crumpp]

If you look at Rechlin data for the Focke Wulf, you will find Focke Wulf is generally conservative.

[Crumpp]

Note that 190A-8 accelerates faster than the 190A-5 when configured in a similar fashion.

I don't think that is the point Widewing.  The point is the data is wrong for the type.

[gripen]

Originally posted by Widewing

As you can see, the bomb/tank rack has a significant effect not only on speed, but upon acceleration as well. Since we do not have American aircraft without integral underwing pylons/shackles, we cannot determine their effect on performance.

There seem to have been a lot discussion on various boards on the A-8 and the rack. Most of the photos show the A-8 with rack, so far I've seen (from those discussions including those pictures Crumpp posted) 6 pictures of supposed A-8 without rack (not sure in every case because A-7 is quite similar without rack and quality of the photos vary) so it appears that a A-8 without a rack was a quite rarity.

In the case of the American fighters there appear to be lot of pictures of P-51Bs without racks, specially in British use and in 9th AF. So if we assume balanced modeling, the A-8 should have rack or the american fighters should have a rackless option.

gripen

[Crumpp]

So if we assume balanced modeling, the A-8 should have rack or the american fighters should have a rackless option.

What a troll.

[gripen]

The AH A-8 has 170 gallons internal fuel capacity so it should have the rack or the internal capacity is wrong.

gripen