fw 190a5 flight model

[lonewulf]

How come then most of the time they did dogfight, and even more so if they were flying a P-47D or a FW-190A?

"When they avoided dogfights was when they flew Spitfires... I've never seen any aircraft type that avoided dogfighting as consistently as the Spitfire...

In fact the avoidance of dogfighting by the late Spitfire marks is so consistent and so extreme I had a hard time believing it, thinking as I was that the weakness of guns forced turnfighting even on 1944 pilots: Because only 2% of shots are on target, the target has to be peppered for a sustained time to be brought down, which doesn't help diving and zooming...

It turns out the Spitfire's 20 mm are really long-range and powerful, and allows the Spitfire to avoid turnfighting where it is at a disadvantage compared to most types, except the Me-109G or P-51 which are roughly equal or slightly inferior to it..."



Gaston, I begin to wonder if you actually comprehend the difference between what people do in the real world, and what people do in simulations. No one in their right mind is going to chance their future on the outcome of a sustained dogfight with an unknown enemy - unless forced to by circumstance. Combat pilots aren't there to test the capabilities of their aircraft or match their skills against those of the enemy. Their job is simple, it is to destroy the enemy as quickly and safely as they can. All sorts of crazy stuff may happen in war comics and movies but in real life where real ammunition is being used (by both sides) that sort of stuff is a no no. Get yourself into a sustained turn-fight with another aircraft and in all probability someone else, someone you haven't seen, will end the fight for you.

[K_Freddie]

Originally Posted by Oryx

Wing loading is measured in kg/m^2 - it is mass divided by area, not force divided by area. Unless you live in a different universe than us, throttle setting cannot change either the mass of the aircraft or the area of the wing.

Wouldn't weight be effected by mass + G-loading with is dependent on AOA, coupled with speed, which is controlled by throttle setting ?

Something a pilot would know instinctively..

Edt: Terminology correction.. 'Mass effect' not being consistent as weight changes. =>> Wing loading = Force / wing area (for want of a basic formula)

[JtD]

No, mass does not change with g. Weight does.

[K_Freddie]

Ja, you're right.. Sorry, I forgot for a moment

[K_Freddie]

I got a bit curious seeing that we're on about the Spit-vs-FW190. decided to have a look at the specs on wiki (if you can trust such a source - no smoke without a fire)

2 specs I find interesting are loaded weight and max takeoff weight. In both case on wiki, the Spits (Vb and XIV) loaded weight is only around 250Kgs below max takeoff weight. whereas the FW (A8 and D9) is a whopping 500Kgs. This is for a heavier aircraft with a weaker engine ??

This make me think that the Spit when loaded is simply flying closer to it's limit of staying in the air, than the FW even with it's higher wing loading. Which might encourage Spit pilots not to get happy about tight dogfights and rather use hit and run, which seemed to be the norm in the latter part of the war.

Something to think about

[JtD]

Maximum take off weight has nothing to do with the ability of the plane to 'just stay in the air'.

Additionally, figures on wikipedia are wrong, for instance loaded weight (8488 lbs) is used for the stated Spitfire XIV maximum take off weight (9278 lbs with 90 gal drop tank).

[K_Freddie]

You'll find an airline pilot will not take off if his a/c is too heavy (close or beyond recommended takeoff weight)... there must be a reason for this.

[JtD]

Yes, there is. In fact there are several.

[MaxGunz]

If you don't take into consideration what the takeoff speeds, runway lengths and air density are then you won't get much out of takeoff weights.

It's like when The Joke would say that more weight on a plane makes the plane faster because hang gliders fly faster with ballast. Yes the gliders do, because if they don't fly faster they will stall when the unballasted, slower glider is still not stalled.
But -powered- airplanes don't get their energy from their weight, they can go faster using the spinny thing up front. More weight just makes their wings have more drag, which BTW is not proportional to wing loading.

[Herra Tohtori]

Well, that all gets really complicated really fast.

Let's compare two aircraft of roughly same engine power, mass, and wing chord profile - only difference being that the other one has more wing area; for the sake of exercise let's keep the wing's aspect ratio also same, ie. chord length increase is proportionally same as wing span increase.

An aircraft with smaller wings has less parasitic drag.

But it has higher wing loading, which means at the same speed it has to use higher angle of attack, which increases the drag.

Both aircraft, however, have a certain optimal angle of attack at which the wing produces the least amount of drag.

Then, their optimal cruise speed is when they are flying at exactly this angle of attack, and the lift is exactly enough to counter the aircraft's weight.


For the aircraft with smaller wing, this optimal cruise speed will be higher than the aircraft with larger wing. What this means is, basically, that the smaller wing aircraft is better optimized for high speed flight and will achieve better efficiency when flown at higher speeds... and will reach higher top speed at level flight with the same thrust output from the engine!

That last part is actually pretty elementary physics. The top speed of any object is achieved when the power output equals friction/drag losses.

When the power output remains constant but drag coefficient reduces, then the drag losses are equalized at higher velocity.



However, things change drastically when these aircraft are compared in high angle of attack situation. At same angle of attack, the aircraft with larger wing will produce more lift and therefore turn better. There are also other, secondary effects such as better acceleration and better climb rate, which both very much explain why lower wing loading typically makes "dogfighting" easier compared to planes with high wing loading.

This does not necessarily correlate with combat effectiveness of the aircraft. The benefits gained in "angles maneuvers" are lost on energy maneuvers. The aircraft with smaller wing will accelerate faster in a dive, it will have higher dive speed limits, it will be more stable at high speeds, and it will lose less energy at dives and zoom climbs as long as angle of attack is reasonably small.


Of course, this is idealized comparison. There are not many examples where these conditions apply. One example that comes to mind is Ta-152C vs Ta-152H-1. In this case, the Ta-152C had smaller wing and Ta-152H-1 had larger wing. However these aircraft differed in other ways; Ta-152C used the DB603LA engine, whereas the Ta-152H-1 used Jumo 213E engine. Additionally the H model's long wing had much higher aspect ratio and thus was better optimized for high altitude flight due to lower induced drag, which is a different form of drag than parasitic drag...


However, comparison of these aircraft in IL-2 largely corresponds to what I just said. The Ta-152 H-1 accelerates better, climbs better, turns better, and at high altitudes it performs quite a bit better.

The Ta-152C has pitiable acceleration and climb rate, turns like a hippo in a bath tub, and top speed is puzzlingly low (I have some suspicions regarding the DB-603 engine model), but it definitely has higher dive speed, dive acceleration, and it retains energy quite well once you get it really going. It also offers excellent stability.

Which is a better airplane would depend entirely on what you were doing and how.



Wing loading of aircraft varies with g-loading, but typically it's expressed in level flight (1g acceleration), where it can be expressed in mass/wing area which colloquially is understood much better by people, than the actual implications of "wing loading".

If you REALLY want to get into it, wing loading is actually expressed in units of pressure. It is, quite simply, the aerodynamic lift force produced by the wing, divided by the area of the wing.

What does this means from the aerodynamic perspective?


As an aerofoil passes through air, it basically does work on the airflow to create pressure differential between upside and downside of the wing. These pressure differentials generate the lift that is used to counter the aircraft's weight.

The pressure differential is not constant over the wing; at some places it's higher, at the edges it's lower. However, if we were to average the pressure differential over the wing, it would turn out to be exactly the same as wing loading: Force of aircraft's weight, over the surface of the wing.

Why then is smaller wing loading preferable? Because the smaller wing loading means your wing needs to create less pressure differential.

Less pressure differential means less work done by the wing on the airflow - which, incidentally, is one source of drag in airplanes.


This is, of course, quite a bit simplified and it would be better to draw an image but I see this represented very, very well in IL-2. FW-190 included.