1C Home   |   Register   |   Today Posts   |   Members   |   UserCP   |   Calendar   |   Search   |   FAQ

Go Back   Official 1C Company forum > 1C Publishing > IL-2 Sturmovik: Cliffs of Dover > Pilot's Lounge

Pilot's Lounge Members meetup

Closed Thread
 
Thread Tools Display Modes
  #191  
Old 06-16-2012, 03:59 PM
Crumpp's Avatar
Crumpp Crumpp is offline
Approved Member
 
Join Date: Feb 2008
Posts: 1,552
Default

Quote:
they said was based on proof only to find out later there was no proof!
Learn about aerodynamics and aeronautical science. There are plenty of references out today on swept wing theory.

Thanks the Germans we have a good understanding of swept wing theory and we have a very detailed mathmatical model with the ability to predict behaviors.

We, meaning the world scientific community has improved upon it, but it was Germans who provided the basic foundation. framework, and direction.

Keep in mind, the United States had one scientist who was working on swept wing theory. His ideas were not accepted by the mainstream.

The United Kingdom had no one at all and their top designers thought swept wing theory was "bloody useless". Unfortunately, their swept wing pioneers were limited to toy gliders with rare exceptions pre-dating WWI.

Quote:
swept wing theory was not taken up in Britain by any of the leading aircraft designers and manufacturers of the day.
http://www.aviationclassics.co.uk/ne...ing-technology

Is it surprising to anyone that the Allies had little understanding or ability to explain the German design decisions on the Me-262?
Attached Files
File Type: zip german Aerodynamic technology.zip (5.08 MB, 2 views)
File Type: zip German Swept Wing Research1.zip (4.07 MB, 1 views)
  #192  
Old 06-16-2012, 04:01 PM
Crumpp's Avatar
Crumpp Crumpp is offline
Approved Member
 
Join Date: Feb 2008
Posts: 1,552
Default

It is not my opinion Tagert. It is how it works.

Pick up a aeronautical sciences book on swept wing theory and read it.
  #193  
Old 06-16-2012, 04:03 PM
ACE-OF-ACES's Avatar
ACE-OF-ACES ACE-OF-ACES is offline
Approved Member
 
Join Date: May 2010
Location: NM
Posts: 2,247
Default

Quote:
Originally Posted by Crumpp View Post
Learn about aerodynamics and aeronautical science.
I have and during that process I have learned that it is best to go with the experts in the filed over self proclaimed experts in a flight sim forum.. Again nothing personal! I just think most here would agree that it would be silly to take your word on it over theirs.

S!
__________________
Theres a reason for instrumenting a plane for test..
That being a pilots's 'perception' of what is going on can be very different from what is 'actually' going on.
  #194  
Old 06-16-2012, 04:04 PM
ACE-OF-ACES's Avatar
ACE-OF-ACES ACE-OF-ACES is offline
Approved Member
 
Join Date: May 2010
Location: NM
Posts: 2,247
Default

Quote:
Originally Posted by Crumpp View Post
It is not my opinion <snip>
Well that is your opinion on your opinion and your welcome to it!

But I am going to stick with the Me262 experts (Jenkins and STORMBIRDS) on this one..

Who said..
  • The 'reason' the outer wings were swept was to correct the cg.
  • The 'reason' the inner wings were swept was to correct the airflow separation.

It is nothing personal!

It is just when you consider the fact that Dennis Jenkins has written more aviation books than most people have read, and that the folks at STORMBIRDS surly reviewed all the data on the Me262 during the process of building reproductions of the Me262.

It would be silly to pick you over them!

But I still want to thank you for sharing your personal beliefs and opinions!

But to be honest, I really don't care about what you personally belive and your opinions!

All I care about is what can be proven.

I mean if we don't draw the line there was is to stop someone from posting in this thread that they 'belive' and are of the 'opinion' that the Germans were assisted by aliens from outer space?

So with that said I think you can understand why I drawn the line there..

I also want to thank you for information and calculations you provided!

But I am sure the likes of Dennis Jenkins and STORMBIRDS are privy to that same information/calculations and MORE and took it all into account during their research of the Me262 and their ultimate statements on the reason why the wings were swept.

Which begs the question as to why they didn't come to the same conclusions you did?

I suspect they wanted to..

In that the whole history channel 'the Germans were supermen' stuff sells these days..

Especially the folks at STORMBIRDS who are pro German tech biased..

But I suspect the stopped short of making the claims you made because they just could not find any real proof of the connections your claiming are there.

That and unlike you they have a reputation to consider!

I mean think about it, nothing would hurt their image, and thus sales, more than for them to say something they said was based on proof only to find out later there was no proof!

So with that said..

We will just have to agree to disagree as to the reasons why the wings were swept on the Me262

S!
__________________
Theres a reason for instrumenting a plane for test..
That being a pilots's 'perception' of what is going on can be very different from what is 'actually' going on.
  #195  
Old 06-16-2012, 04:12 PM
Crumpp's Avatar
Crumpp Crumpp is offline
Approved Member
 
Join Date: Feb 2008
Posts: 1,552
Default

Here you go Tagert,

A good simple primer on the basis of swept wing theory.

http://www.desktop.aero/appliedaero/...eeptheory.html
  #196  
Old 06-16-2012, 04:18 PM
ACE-OF-ACES's Avatar
ACE-OF-ACES ACE-OF-ACES is offline
Approved Member
 
Join Date: May 2010
Location: NM
Posts: 2,247
Default

Quote:
Originally Posted by Crumpp View Post
Here you go Tagert,

A good simple primer on the basis of swept wing theory.

http://www.desktop.aero/appliedaero/...eeptheory.html
No need I have several books on the subject, that I have read by the way!

But I am still incline to go with the experts statements over yours and even my own for that mater!

But thanks for the link!

S!
__________________
Theres a reason for instrumenting a plane for test..
That being a pilots's 'perception' of what is going on can be very different from what is 'actually' going on.

Last edited by ACE-OF-ACES; 06-16-2012 at 04:20 PM.
  #197  
Old 06-17-2012, 03:55 AM
Crumpp's Avatar
Crumpp Crumpp is offline
Approved Member
 
Join Date: Feb 2008
Posts: 1,552
Default

Quote:
No need I have several books on the subject
Good, try opening them and reading. If you need help understanding them I am sure somebody can help you.

Quote:
The 'reason' the outer wings were swept was to correct the cg.

Crumpp says: yes it was...see above and it fits with swept wing theory.

The 'reason' the inner wings were swept was to correct the airflow separation.

Crumpp says: yes it was...see above and it fits with swept wing theory.
Quote:
Originally Posted by Crumpp View Post
Thank you for the laughs!! I guess you don't understand the fact your sources are not wrong at all. They only convey a portion of the story but their facts are correct.




You do realize that in the decades since WWII, we in the United States have had time to sort through the data compliled by the Germans. We have a much better understanding of their work and swept wing theory.

That is why those papers were published and presented at conferences for engineers and scientist.

In 1946 when the NACA and USAAF references your "experts" use were written, the United States had little to know understanding of swept wing theory.

Notice the P-80 had straight wings.....


Yes, the outer wings were swept to eliminate flow seperation!!

What do you think raising critical mach number is all about?? That is the whole point of adding sweep!!

Behind the normal shock is seperated flow. If we increase the critical mach, we reduce the amount of seperated flow on the wing.

Yes, the aircraft benefited from just 18 degrees of wing sweep!!!

Our critical Mach number is raised by reciprocal of the cosine of the angle of sweep. So for 18 degrees of sweep we see a 1.05146 increase to critical mach.

So mach limit of Mach .8 becomes a new limit of .84.

Now at sea level that is represents a 30mph increase in speed!

Now the drag reduction is proportional to cos^2<angle of sweep>

Or a 9.5% reduction in drag.....

Not a bad call on the part of Mtt to add 18 degrees sweep based off their advanced knowledge of swept wing theory. By keeping the sweep moderate, they certainly avoided all the stability and control issues found with sweep angles and engine nacelles.

Yes the center portion was adjusted to expand the forward CG limits!!!





http://www.google.com/url?sa=t&rct=j...kmfr_LD2mjThuA

After flight testing though, the original high aspect ratio wing design CG limits were not suitable for the higher mach limits the outboard sweep allowed.

As an aircraft enters transonic flight, the progression of the normal shock moves the AC rearward reducing the elevators effectiveness.
Additionally, the downwash angle behind the wing is decreased due to the seperated flow behind the normal shock. This increases the angle of attack of the horizontal stabilizer which is the main cause of mach tuck.

An airplane originally designed to have a straight wing would need to expand the forward CG limits if you are to increase the elevators effectiveness if you are going to fly in the transonic realm.

The sources you quote are correct and the sources they use were written at a time when you could count on one hand the number of United States Aereonautical Engineers who knew anything at all about swept wing theory.
  #198  
Old 06-17-2012, 11:30 AM
fruitbat's Avatar
fruitbat fruitbat is offline
Approved Member
 
Join Date: Jan 2010
Location: S E England
Posts: 1,065
Default

Quote:
Originally Posted by ace-of-aces View Post

but i am still incline to go with the experts statements over yours and even my own for that mater!

S!
+100000
  #199  
Old 06-17-2012, 11:55 AM
NZtyphoon NZtyphoon is offline
Approved Member
 
Join Date: Feb 2012
Location: NZ
Posts: 543
Default

Quote:
Originally Posted by Crumpp View Post
Good, try opening them and reading. If you need help understanding them I am sure somebody can help you.
Closed Thread

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 11:56 PM.

Based on a design by: Miner Skinz.com

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright © 2007 1C Company. All rights reserved.