Author Topic: Maybe the 190s arent wrong....or how to be really unpopular in 1 step  (Read 12880 times)

Offline Simaril

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #90 on: February 01, 2006, 05:28:09 AM »
Quote
Originally posted by Crumpp
....snip.....

I think your right.

All the best,

Crumpp



Crumpp,

I respect your knowledge of LW history, but I'm coming to have doubts about your intellectual honesty. I'm seeing you again select the parts you like and ignore the parts you dont.


You picked a comment at the end, but didnt respond to what went before. SO, I'm interested in your thoughts about the following questions I asked in posts above:

1) Why doesnt the heavy framing in AH serve as a reasonable programming expression of a cramped cockpit?

2) Can we acknowlege that there may be reasonable uncertainty about the objectivity of LW testing, given the bureacratic turf battling, central disarray, and homicidal tendencies of the Reich?
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Offline Charge

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #91 on: February 01, 2006, 05:34:07 AM »
Ummm, or maybe it is a lot more complicated, and as Gripen tried to point out that exact knowledge of turn performance requires the knowledge of a LOT more variables to determine the exact turn performance of a certain a/c. And that means that those calculations would be very much more complicated.

BTW, picking on 190 does not make you unpopular, Simaril, as you assume in the topic of this thread. Quite contrary. It makes you the part of the "winning team"... :aok

-C+
"When you wish upon a falling star, your dreams can come true. Unless it's really a giant meteor hurtling to the earth which will destroy all life. Then you're pretty much screwed no matter what you wish for. Unless of course, it's death by meteorite."

Offline Charge

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #92 on: February 01, 2006, 05:49:44 AM »
I'll have go.

"1) Why doesnt the heavy framing in AH serve as a reasonable programming expression of a cramped cockpit?"

Because that can be impelemeted when determining the pilot movement limits. Thus the limits do not need to be implemented in c'pit framing. IMO that would be simply idiotic. The crampedness of a cockpit is relative. There was a Finnish pilot of 195cm who flew 109s. It sure was cramped for him, but I think any plane  was cramped for him. And after all he did fit in 109...
BTW how is a cramped c-pit bad anyway? You can't breathe? Move? Lay down? What? That is what I call "picking".

2) Can we acknowlege that there may be reasonable uncertainty about the objectivity of LW testing, given the bureacratic turf battling, central disarray, and homicidal tendencies of the Reich?

Why can't we assume the same for allied testing, too, considering that the war was a "good business" as was reflected by many overly optimistic performance figures for certain combat aircarft which couldn't reach those numbers in operative equipment?
   
-C+
"When you wish upon a falling star, your dreams can come true. Unless it's really a giant meteor hurtling to the earth which will destroy all life. Then you're pretty much screwed no matter what you wish for. Unless of course, it's death by meteorite."

Offline justin_g

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #93 on: February 01, 2006, 05:51:34 AM »
Quote
Originally posted by gripen
justin_g
I don't know what is the problem with this. If we wan't to know what Cl is required for known airframe at given 3D conditions (lift, speed, density, wing area), we can calculate it simply with the formula:

Cl = L / (A * .5 * r * V^2)

It gives the Cl which the wing must have at given conditions despite what ever is the geometry of wing. There is no need to know AR, wing twist, profile etc. at this point. If we want go further to induced drag analysis or AoA analysis  then we need additional information.

gripen


cc, I get you now. :o I was approaching it from the other end, so to speak...

Offline BlauK

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #94 on: February 01, 2006, 06:10:27 AM »
Simaril,
1) would it not depend pretty much on what is meant with "cramped"? IMO, it refers to less space for movement, but what is enough and what movements are required is also a relevant question. Why should the less movement be translated as less visibility?

Some previous threads have already discussed the effect of the missing armoured glass refraction. It is a major disadvantage for visibility -> SA -> ability to fight. The thicker the glass, the bigger the disadvantage from the missing refraction. In additionto that we already miss the "stereo view" of 2 eyes, which would already overcome some disadvantegae caused by the cockpit frames.
« Last Edit: February 01, 2006, 06:12:29 AM by BlauK »


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Offline Crumpp

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #95 on: February 01, 2006, 09:18:08 AM »
Quote
but didnt respond to what went before.


It's covered.  You picked an opinion.

Moving on:

I believe the P51 does benefit from refraction.  In one thread pictures were compared with outside views of the framing in the Mustang.  From the inside one of the frames seemed to disappear.

This is the effect of refraction.  It is very noticable in the cockpit of Black 3.  The framing from the armoured glass cannot be seen from the inside.  

Quote
turn radius does depend on wing area.


No.  Turn radius is a function of Power available to power required.  

Wingloading is a reflection of that relationship in turn radius.  It is not a good reflection of that relationship for turn rate.

Both components go into sustained turn performance of a fighter.


All the best,

Crumpp
« Last Edit: February 01, 2006, 09:37:31 AM by Crumpp »

Offline Crumpp

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #96 on: February 01, 2006, 09:51:50 AM »
justin,

Your absolutely correct.

Quote
Gripen says:

It gives the Cl which the wing must have at given conditions despite what ever is the geometry of wing.


Quote
Gripen says:

If we want go further to induced drag analysis or AoA analysis then we need additional information.


The very fact your not considering the gemometry of the wing makes it 2d theory.  Don't get confused justin because wing area alone is considered in the formula.

You posted the formula's for 3D wings and explaination.  3D theory takes into account indcued drag and AR by it's very nature.  2D theory does not.

http://www.aerospaceweb.org/question/aerodynamics/q0167.shtml

Gripen is wrong and does not understand the differences in the theory or terminology.

All the best,

Crumpp

Offline justin_g

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #97 on: February 01, 2006, 10:17:32 AM »
Actually I was wrong, in this application. I was actually thinking about calculating values of CL over a range of AoA, which is where the 3d theory will produce more accurate figures.

But if you just want the CL required to match the numbers for lift, speed, density and area then it is perfectly acceptable to use the formula gripen has listed. The page here has a worked example using real data.

Offline Angus

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #98 on: February 01, 2006, 10:20:06 AM »
Aint seen Gripen slip much on the boards. Seems to know his stuff.
It was very interesting to carry out the flight trials at Rechlin with the Spitfire and the Hurricane. Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land. (Werner Mölders)

Offline Simaril

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #99 on: February 01, 2006, 10:50:07 AM »
Crumpp and Charge,

PLease dont misunderstand me. i am absolutely not on a mission either for or against any plane, and I'm certainly not a LW basher. I started with the Yak, then spent a pretty good chunk of time in the Dora in AH1. Tried to learn TnB in the old Spit IX/V. Best 'score" time came in the old G10 doing dedicated buff hunting. Tinkered with the 38 but wasnt ready skillwise, and now using a mishmash of 50cal planes to work on gunnery and SA. I'd bet I have more career kills in LW than any single other plane -- so I'm far from a basher.

I just love the variety of trying different things. I really like it when those things are historically representative ("representative" becaue you cant be "accurate" in front of a monitor).

I dont particularly like it when people are so focused on their agenda that it influences their search for "truth".



So, thanks for the clarification about the refractive effects of the armor glass.  Thats an interesting point; was the glass convex to some degree to give a wide angle? Now that I think about it, if it wasnt convex, wouldnt that cause a LOSS of a correponding portion of the viusl field? (I'm not good at saying this, but if there was a refraction that gave a view without the framing WITHOUT concavity to widen the angle, then objects woudl take up the same angular size that would have been present without the glass. SO, every "extra" thing you caould see would have to be at the expense of something you couldnt see -- becasue the pilots overall angular visual field was unchanged and the size of objects was unchanged, still a 1:1 correspondence.) So, in effect, the lost visual field from the frames woudl STILL BE THERE with the only change being that you couldnt see the frame.

Or have I thought through this wrong?




The testing question is an interesting one. I didnt mean to argue that manufacturer's testing would be more reliable in a democracy; and certainly factors other than deciett can contribute to significant differences in test results (i.e. "clean" airframe, optimal tuniing, etc).

Instead, I was thinking about what pressures the military test arms had to contend with. There is no doubt that teh Reich's military had a higher risk of powerful -- and even lethal -- political pressures. Highest levels of command were unpredicatble and implacable, not susceptible to reason.

And, the military procurement system was not particularly rationalized. So, entirely apart form the self preservation aspects, with very tight resources and uneven (or irrational) distribution of those resources -- wouldnt it be pretty easy to see bureaucrats buffing results to avoid getting their programs cut? The combination of resource scarcity, overlapping and competing fiefdoms, and a "royal court" that could bestow favor or punishment at a whim just sounds like a recipe for fuedal behavior, doenst it?  It just seems uncertain to me...maybe results woudl be straight up, maybe not.

The US just didnt have those pressures because the resources were abundant. They could afford to keep making P-39s when the planes were obviously substandard, because, well, they could. When the planning boiards were wrong, like with the US torpedos, the truth came out in spite of the career implications -- institutions liek the press and independent judicial style review branches werent cowed by political pressure. And you cant minimize the impact of national culture. The american sterotype is aggressive, results oriented, and willing to trample on tradition and some times institutions to get the job done. That's different than the european and germanic tradition, so might their have been less willingness to buck th einstitutions?

Just musing...not accusing.

Simaril
Maturity is knowing that I've been an idiot in the past.
Wisdom is realizing I will be an idiot in the future.
Common sense is trying to not be an idiot right now

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Offline Crumpp

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #100 on: February 01, 2006, 11:03:00 AM »
Quote
But if you just want the CL required


No one has disputed the accuracy.  CL is a dimensionless number.

What Gripen was referring too was my opinion of which theory is more accurate for analysis.  Which has nothing to do with this discussion.

Quote
These equations are 2D. 3D is even more accurate.


The equation Gripen posted IS 2D theory.

The confusion comes from bozon question:

Quote
is your idea of CLmax include the area of the wing or is it unitless?


Which I took to mean:

"Area of the wing" = finite wing

"Unitless" = infinite wing

Because I know Bozon understands CL is dimensionless and it would be childish to imply otherwise.  So it did not even enter my mind that he would be asking if CL was dimensionless!

Hitechs example in this discussion is correct and an accepted method of estimation. However the designers in WWII knew much more about aeronautical engineering and their own designs than ANYone on these boards or at HTC.

The entire wing loading gain of the FW-190 amounts is 6% to 7% with a 23% increase in horsepower over the lifetime of the design.  The thrust increase is not including more efficient propellers.

You cannot get around the fact the Spitfire Mk XIV gained a much larger percentage of wing loading and equal power gains over the Spitfire Mk IX.  In the air, to trained test pilots using domestic and familiar designs, the differences were imperceptible.

All the best,

Crumpp

Offline Crumpp

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #101 on: February 01, 2006, 11:20:38 AM »
Quote
So, in effect, the lost visual field from the frames woudl STILL BE THERE with the only change being that you couldnt see the frame.


No the effect is you see around the supports.  Light is bent around them.

Here is a good website with a nifty applet.  Think of the support being the center of the axis.  Light is bent around the support and you are looking behind it.  Of course it only works to a point.  The supports seem about 3/4 as thick as the AH cockpit on the FW-190 with nothing showing at the bottom nor can you see any of the armoured glass framing.  You have a clear view of the nose.  Our plane is level on supports now.  Angle it upwards if it was on the gear and your view of the ground in front of you would disappear.

http://www.ps.missouri.edu/rickspage/refract/refraction.html

Quote
I really like it when those things are historically representative


So do I.  None of the Focke Wulf pilots noticed any handling deterioration in the FW-190A8.  They all say it was best performing fighter variant.

This is backed up by the science as well.  The differences between an FW-190A3's turn ability and the FW-190A8's should be imperceptible from the cockpit.

Now people are being silly in defense of a game shape if they think anyone is trying to make the FW-190 a turn fighter.  Just saying the same physics applies and these designers were not stupid.  They knew much more about this stuff than we do.

All the best,

Crumpp

Offline Waffle

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #102 on: February 01, 2006, 11:50:24 AM »
Here we go again :D

You cannot see through metal...light does not pass through the metal framing.

Take out the glass - look at the feild of view from the pilots posistion.

Put the armored glass in and it will be the same image / same feild of view only 2" closer to the pilot. It would have the appearance of smaller frames due to the refraction, but no visable feild of view gains will happen.

You dont see around the supports.

Offline Crumpp

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« Reply #103 on: February 01, 2006, 11:58:15 AM »
Quote
Here we go again


Come down and sit in the cockpit.  You can check it out yourself.  Nobody is claiming your seeing through metal.  The light is refracted is all.  It is no different than the properties an optical lense uses to manipulate field of view or magnification.

All the best,

Crumpp
« Last Edit: February 01, 2006, 12:05:52 PM by Crumpp »

Offline Waffle

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Maybe the 190s arent wrong....or how to be really unpopular in 1 step
« Reply #104 on: February 01, 2006, 12:03:30 PM »
put 2 cents on the outside of the frame and tell me if you can see it. :D