Maybe the 190s arent wrong....or how to be really unpopular in 1 step

[Crumpp]

What a silly request, Waffle.  Of course you would not see it behind the frame.  However if you put a coin on the nose in front of the cockpit or back that same coin a few inches off the frame, you will certainly see it.

[Crumpp]

What we have in the cockpit views in this game is not a simulation of the actual field of view taken from same perspective.

All the best,

Crumpp

[KAntti]

Originally posted by 38ruk
I just did some tests in a 47N 50% fuel no ord , mine has no problems dipping its left wing and doing a complete stall. do ya all have the stall limiter turned off??  LOL

38ruk, maybe I was a little of on my comments about the 47. What I mean was that even though the p47 does perform something that could by someone with great benevolence be seen as a stall, it nowhere near perform an actual stall nor spin.

What p47 D 25% without ord. does: U give full flaps and take off, when speed approaches 90 mphs u pull hard, but just enough to keep the wing from dropping (ending in app 50 - 60 %).

U wait until the stall horn stops yelling (50 mph-ish) and wait for the thing to stall. When the stall comes u keep that wing (most propably the left wing if ur controls are straight at the stall) from dropping by applying right aileron.

At this point the nose starts to gently come down from the sky, and the plane is still most definatively out of air, but you still have full use of your controls. If the wing continues to trouble you, aply some right rudder as well. In real life from this point on, at this altitude u would without a doubt go in to a spin and end up in a flat mark on the deck (the rudder being still in one piece is a possibility). But since this is AH and not even the Spit is able to perform the spin, what the heck, lets do it!

U apply the right rudder and your p47 enters in a sideslip (while your left wing is stalling, this is fun) and loses altitude very fast, but your wing still keeps up, which was the idea. Then u just wait until the nose approaches the horizon and the plane gathers some speed (u dont need much to let the rudder go), and voila! U have just done a manouver no aircraft (I know this is an overstatement but, maybe some extra 300 or somthin...) in the whole wide world is able to do and survive. U have actually stalled and done a sideslip during the stall under 300 ft (95 meters), yey!

If u call this a normal stall performance and lowspeed manouvering ability for the p47, I would like to see to what plane were the pilots referring to when they thought p47 has poor performance low and slow.

[Waffle]

nope - I'm pretty sure its a 90 degree feild of view....

But it's pretty fun zoomed in to 30-45 degrees with track IR.

[gripen]

Crumpp,
The equation I posted is derived from 2D but it uses known wing area ie finite wing so it's purely 3D.

bozon asked if CLmax include the area of the wing or is it unitless. While unitless is not exactly right word, you should have understood the question if you actually understand what you are talking about. Anyone can draw his/her own conclusions from your answers...

gripen

[BlauK]

Waffle,
You already tried to argue against the refraction issue in this thread.
Again, no... one cannot see through the frame, but the refraction allows one to see partly around it! That makes a difference in available viewing angle and therefore a huge difference in what the extra blocking part covers in the distance.

[BlauK]

LOL.. it is mildly amusing how some people still have to try to build their egos and to diminish others by getting personal. Is it not enough to let the issues and facts do the arguing?

[Charge]

"Highest levels of command were unpredicatble and implacable, not susceptible to reason. "

Simaril, I do understand what you are trying to say here and I have thought of it myself. However, even if at some administrative level there might have been some kind of political hassle I find it hard to belive that it would have gotten through to detailed technical or scientific documents. Which doesn't mean it is not possible.

I think those documents were simply out of the comprehension abilities of German high(-est) command.

I have most doubts of the documents that are merely general impressions of things without even basic scientific approach. Just as the Jug/FW documents. Even if they say that FW was superior in slow speed I find it doubtful too.

IMO those documents have only implications of the nature of those a/c but not the actual performance.

-C+

[Crumpp]

The equation I posted is derived from 2D but it uses known wing area ie finite wing so it's purely 3D.

NO it is not.  Cut and dry it is 2D theory equation.

You confuse reference area with the influence of induced drag and AR.

http://www.aerospaceweb.org/question/aerodynamics/q0015b.shtml

That being said, while 3D theory is more accurate when used accordingly, the standard this particular 2D theory formula is fine and gives reasonable predictions.  Some formulas in 2D theory are best if used only in specific circumstances and if used outside those parameters can give erroneous conclusions.  Same applies with 3D theory.

There are quite a few theories of the mechanics of flight out there:

 

This BASIC computer program uses the classical monoplane equation from lifting line theory to solve for the lift and induced drag coefficients and the spanwise load distribution on a specified wing ( 3-D ). Lifting line theory assumes that a wing's behavior at any spanwise location where the equations are solved is essentially two-dimensional ( no spanwise flow ). It is also based on a model using a bundle of lift inducing vortices placed at the unswept quarter chord of the wing. The method is, therefore, only valid for wings with unswept quarter-chord lines and with moderate-to-high aspect ratio.

http://www.aoe.vt.edu/~marchman/software/

Here is a great paper on how designers can manipulate almost any wing design to mirror an elliptical shaped wing with no twist's induced drag production.  This why nobody builds elliptical wings as they are much more expensive to manufacture while offering few benefits in the air.  Goes back to the monsterously silly thread you linked, Gripen.  The one you argued that woods formula was wrong.

http://www.mae.usu.edu/faculty/wphillips/MAE5500/JoA-Vol41-No1.pdf

 

All the best,

Crumpp

[Crumpp]

Even if they say that FW was superior in slow speed I find it doubtful too.

It is interesting Charge that more than one flight test notes this same characteristic.

[TimRas]

Originally posted by hitech
Crumpp you are so far off on the discusion of power weight and lift as it applies to turn performance ill just throw out some basic numbers from  spreed sheet I did.

Given a plane with a max turn of 2.3 g at 160 mph . (In the realm of a lot of war birds)

Would create a turn radius of 825 ft and a time around turn of 22.1 secs. I.E. Bank angle of 64.22.

Now lowering the weight of that plane. by 10 % would make a turn raidus of 727 with a circle time of 19.46, Bank Angle 66.96

Increasing power by 30% on the orignal weight would have the following effect.

Turn Radius 798 circle time rate 19.5 and a speed of 174. Bank Angle 68.59

Ill let you draw your own conclusions. They should be very entertaining.

HiTech

Tried to duplicate HT's spreadsheet:
Blue line is turn radius [ft]
Red line is turn rate [deg/s]
Starting from 2.3g, 160mph.
Weight has much greater influence than power.

[bozon]

Crumpp, I give up. I showed you that turn radius does depend on wing area, if you want, through reducing the "power required", but you refuse to listen. Thank you for bringing this up since it was interesting and sorry again for my bad english confusing "unitless" and "dimentionaless" terms.

I'll add just one more thing which you may ignore - Gripen is not talking about calculating Cl on a computer, he's talking about measuring it. Hydrodynamic simulations on a computer 2D, 3D with or without thermodynamics are not the most reliable things especially when dealing with irregualr shapes and the interesting part is the generation and decay of vorticity. This is why engineers test everything very carfully on scaled models before actually trying to fly it.

KAntti: I would like to see to what plane were the pilots referring to when they thought p47 has poor performance low and slow.

Make the distinction between performance and handeling. P47 has very poor slow speed performance (turn radius/rate) even in AH if you look at kweassa's tests. It rivels the 190s for last place. Slow speed handeling is another issue. I don't know how good it was but the P47 was not known for poor slow speed handeling or nasty stalls like the F4U or the P51 or the 190. It is extremely hard to tell how the real thing handeled is these extreme conditions, so AH might be spot on or not.

Bozon

[Simaril]

Originally posted by Crumpp
No the effect is you see around the supports.  Light is bent around them.

...snip...

All the best,

Crumpp

Crumpp,

I am not an engineer, so I cant evaluate aerodynamic claims. But, I do have a passing familiarity with refraction.

You, on the other hand, do not.

Refraction DOES NOT “bend” light around corners, it REDIRECTS linear light.The effect of a lens “bending light” occurs because the interface between differing optical densities (ie air and glass) takes place on a smoothly curved surface. I could link you to a site that might get the idea across, but for the purposes of this discussion I’ll limit myself to the armor glass question.

Waffle is 100% correct that the view from the near side of a flat surfaced block of armor glass will appear to show the precise view seen from the far side of the same homogenous block. This is exactly the principle underlying fiber optic technology. It also why framing "looks" smaller"  through the block-- you're only seeing the part visible from the far surface of the glass.

Rather than draw the diagram, let me have you think of it logically: refraction happens when light’s incident angle is redirected at an interface between two substances of differing optical density, with the deviation the light’s previous path being proportional to the ratio between the two substances’ density. (as I remember.....)

What you have chosen to overlook is that light passing through the armor block goes through TWO such interfaces – AIR --> GLASS, then GLASS --> AIR. Since we’re talking about ratios, the mathematical outcome of these two angle ratios is…..ONE. There is no net redirection in the angle of light. The effect, rather, is that of displacing the viewing position. It’s a linear displacement, not a curved one – the light path mimics the shape of the German SS lightning bolt.

To “bend” light around an obstruction requires image distortion, unless you’re willing to trade unrefracted field of view for the new stuff you see. IN other words, without distortion, it’s a periscope -- you have the same angular field of view in a new direction. To take a, say, 6 cm surface and get 10 cm worth of view field, YOU HAVE TO DISTORT THE RELATIVE DIRECTIONS OF LIGHT TO INCREASE THEIR "SPREAD" . In other words, you make a lens.. and this kind of single lens will have distortion. With distortion, you can see more angularly– but you get a (conceptually) some degree of fish eye lens effect, which would be unacceptable for precision views like gunsights. If you want to argue this, I’ll be happy to do some research and explain it to you further....this stuff is off the top of my head, based on my understanding of the human lens.



Your talk of how these engineers were smarter than we are smacks of dogmatic worship, almost religious ardor. They were not smarter than us…they were good engineers using 1940s technology. In fact, the germans spent energy and limited resources developing “wonder weapons” whose practical impact could have been predicted to be minimal had anyone bothered to take the time to think about it – for example, the V2. An awful lot of effort and diversion of limited resources to deliver a 1 ton bomb….Meanwhile the backward allies spent technology on mass production techniques, chosing (for example) to keep less advanced designs in production to avoid drops in the supply stream.  Who would you say was actually smarter?

[KAntti]

Bozon, I am not accusing only the p47 of being poorly modeled or something. I am telling u that the whole FM of AH is generally flawed because it totally lacks things like spin (and in this case stall as well).

For me this is not an big issue as I have allready accepted that this game has nothing to do with real life and that the plane set has been equalized by taking from the rich and giving it to the poor.
The thing that bothers me is that some people insist that this is not the case and actually try to make erratic cases to prove their point.

As you can see there is no case to be made by referring to actual events and testimonials from the era. I bet the only way one might get close is to sit couple of todays pilots in front of the game and let them tell what they think of it. There are lots of warbirds flying around, ask the pilots of them to visit AH convention or smthin and tell us (and HT) how a plane should or should not handle.

[Waffle]

Originally posted by BlauK
Waffle,
You already tried to argue against the refraction issue in this thread.
Again, no... one cannot see through the frame, but the refraction allows one to see partly around it! That makes a difference in available viewing angle and therefore a huge difference in what the extra blocking part covers in the distance.

You're totally missing the point....

Even if the canopy frame looks thinner (because it's shifted due to the refraction) you are not going to magically get more feild of view from a flat piece of glass.

So if you're looking through it - and you can see the frame..even if it looks super thin - you are still seeing the frame. From that point there is no feild of view growth from a flat piece of glass.

Also on the 109s the brackets that held the glass in are blocking alot of the refracted image from a center POV.