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basic aerodynamics - 10/11/2003 8:29:26 AM   
Semi Retired Aviator



Posts: 484
Joined: 9/20/2003
From: Melbourne Victoria, AUSTRALIA
Status: offline 		Most of those who contribute here are probably well versed in aerodynamics. Some perhaps not quite so. The following link will take you to a good site if you desire to read a little about the basics, how controls surfaces work etc

When you get there, go to the bottom left and click on Beginners Guide to Aeronautics. When that page comes up, go to the bottom left and click on the green box titled Aerodynamics Index.

That brings up more information than you will ever want about the theory of flight, and also has some interesting links, including one to where it all started, Kittyhawk, now over a hundred years ago.

The blocks on Aircraft Parts, Motion, and Forces will give you a good grounding.

Sorry if this information has appeared elsewhere.

http://www.grc.nasa.gov/WWW/K-12/airplane/bga.html

< Message edited by JapanFlyer -- 12/13/2003 3:28:00 AM >
       Post #: 1

Suggestion for moderators - 10/11/2003 5:48:46 PM   
Ben Lanterman



Posts: 1286
Joined: 10/27/2002
From: St. Charles, MO, USA
Status: offline 		It might be nice to have this as a link at the beginning of the forum. It's pretty nice.


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RE: Suggestion for moderators - 11/14/2003 2:01:14 AM   
Abraxxas



Posts: 342
Joined: 5/2/2003
From: Plover, WI, USA
Status: offline 		This should definately be linked to somewhere in this forum, that is a great resource.

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"Hey, everybody land for a minute and shut your planes off, I have to call in sick..."
It must be 8am at the

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RE: Suggestion for moderators - 11/23/2003 2:28:59 PM   
N1EDM



Posts: 1983
Joined: 7/19/2002
From: Brockton, MA, USA
Status: offline 		I've seen this before and overlooked it. Thanks for bringing it to my attention once again. I just put a link to it on my club's web page (ssrcc.org)

Thanks again,

Bob

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RE: Suggestion for moderators - 11/24/2003 1:36:44 AM   
JimTrainor


 

Posts: 1308
Joined: 10/25/2002
From: Ontario, ON, CANADA
Status: offline 		More sites for the collection:

Aerodynamics animated using flash animations.
http://142.26.194.131/aerodynamics1
(I hope that's a static IP address - I can't locate a domain name for it.)
This comes from Selkirk College in British Columbia, Canada.

Ground School, by the Australian Ultralight Federation
As an online resource, I thought it worthwhile.
http://www.auf.asn.au/groundschool/contents.html

"See How It Flies - A new spin on the perceptions, procedures, and principles of flight. "
One persons self published, on line, book about flying.
http://www.av8n.com/how

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RE: Suggestion for moderators - 12/8/2003 12:19:24 AM   
dick Hanson



Posts: 10203
Joined: 12/12/2001
From: slc, UT, USA
Status: online 		Wow - lots of great info out there .
Here are some rules I larnt:
1- If the plane is extremely light - the CG does not matter
2-If the plane is too heavy - it still don't matter.
3- If you got enuf power - nuthin else matters .
4-If you ain't got enough power - same thing.

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RE: Suggestion for moderators - 12/8/2003 3:43:04 PM   
banktoturn



Posts: 713
Joined: 8/22/2002
From: Bloomington, MN,
Status: offline
quote:

ORIGINAL: dick Hanson

Wow - lots of great info out there .
Here are some rules I larnt:
1- If the plane is extremely light - the CG does not matter
2-If the plane is too heavy - it still don't matter.
3- If you got enuf power - nuthin else matters .
4-If you ain't got enough power - same thing.


Dick,

I don't think you should make the claim here that CG doesn't matter, no matter how light or heavy the plane is. This is simply not true, and it's not good to give anyone the impression that he/she can ignore CG location if their plane is light enough.

banktoturn

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RE: Suggestion for moderators - 12/8/2003 4:53:35 PM   
dick Hanson



Posts: 10203
Joined: 12/12/2001
From: slc, UT, USA
Status: online 		But it is true .
If the plane weighs ZERO- why bother with CG
If it is too heavy to fly - then the CG is of no importance.
These were both comments made to show that there are designs which -if taken to the extreme-- no longer fit into the accepted envelope of design criteria.
Once a craft has a finite criteria - then the relative design needs can be determined.
All of the carefully worked out airfoils for a B24 bomber - are of no use for a EXTRA 330 acrobat.
In fact the airfoils of the EXTRA are look unflyable to some.
The flate plate wing on a 8 ounce electric is the best airfoil - but is counter to any design needs for a General Aviation light plane.
On my IMAC models - the CG is very important -but on my extremely light electrics - it is of very little importance- these things have wing loadings of only a couple of ounces per sq ft.

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RE: Suggestion for moderators - 12/8/2003 5:07:59 PM   
banktoturn



Posts: 713
Joined: 8/22/2002
From: Bloomington, MN,
Status: offline
quote:

ORIGINAL: dick Hanson

But it is true .
If the plane weighs ZERO- why bother with CG
If it is too heavy to fly - then the CG is of no importance.
These were both comments made to show that there are designs which -if taken to the extreme-- no longer fit into the accepted envelope of design criteria.
Once a craft has a finite criteria - then the relative design needs can be determined.
All of the carefully worked out airfoils for a B24 bomber - are of no use for a EXTRA 330 acrobat.
In fact the airfoils of the EXTRA are look unflyable to some.
The flate plate wing on a 8 ounce electric is the best airfoil - but is counter to any design needs for a General Aviation light plane.
On my IMAC models - the CG is very important -but on my extremely light electrics - it is of very little importance- these things have wing loadings of only a couple of ounces per sq ft.


Dick,

I don't think your analysis of the two extreme cases ( zero weight and too heavy to fly ) are of much use for someone looking for some "basic aerodynamics". Your final sentence is simply false: CG is of no less importance for a plane with low wing loading than for a plane with normal wing loading. This would be a bad nugget of false wisdom to pass on to someone looking for some advice to be used in building/flying his/her own plane.

banktoturn

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RE: Suggestion for moderators - 12/8/2003 5:27:30 PM   
dick Hanson



Posts: 10203
Joined: 12/12/2001
From: slc, UT, USA
Status: online 		OK-- but have you ever worked with a model having 2 oz ft loading?
basic aerodynamics -is a moving target in my book.
that is - what is basic for a 4 ounce flying plate - is not related to what is Basic for a - - Cessna 172 -
I use the Extreme examples - because I have found it to be very helpful in seeing how things are affected.
If you stay within set boundries - you miss a lot.
You can't make omlettes without breaking eggs.

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RE: Suggestion for moderators - 12/8/2003 6:35:04 PM   
banktoturn



Posts: 713
Joined: 8/22/2002
From: Bloomington, MN,
Status: offline
quote:

ORIGINAL: dick Hanson

OK-- but have you ever worked with a model having 2 oz ft loading?
basic aerodynamics -is a moving target in my book.
that is - what is basic for a 4 ounce flying plate - is not related to what is Basic for a - - Cessna 172 -
I use the Extreme examples - because I have found it to be very helpful in seeing how things are affected.
If you stay within set boundries - you miss a lot.
You can't make omlettes without breaking eggs.


If you start with a flawed understanding of what is going on, you miss more.

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RE: Suggestion for moderators - 12/8/2003 7:35:45 PM   
dick Hanson



Posts: 10203
Joined: 12/12/2001
From: slc, UT, USA
Status: online 		absolutely -
and I was fed the old theories of how wings lift and that's how planes flew - Once I finally got over that - things made sense.
for example --On our models - the airfoils are probably the least important part of why they fly -
wing loading and powerloading can replace almost any other "important " stuff.

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RE: Suggestion for moderators - 12/8/2003 7:53:17 PM   
banktoturn



Posts: 713
Joined: 8/22/2002
From: Bloomington, MN,
Status: offline
quote:

ORIGINAL: dick Hanson

absolutely -
and I was fed the old theories of how wings lift and that's how planes flew - Once I finally got over that - things made sense.
for example --On our models - the airfoils are probably the least important part of why they fly -
wing loading and powerloading can replace almost any other "important " stuff.


The choice of the best airfoil, which is not what I was commenting on, does depend on the speed at which the plane flies, and is often not the most important factor affecting a plane's performance. The effect of CG placement on stability, which is what I was commenting on, does not depend on the speed at which the plane flies. It is a disservice to anyone expecting to get good advice here to make the false statement that CG doesn't matter for slow flying planes.

I have had some exposure to the 'old theories', as opposed to the popular misinterpretations of them, and I have also read several of your explanations in various threads. I have not yet had any reason to abandon the 'old theories'. You just need to know when they apply and when they don't.

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RE: Suggestion for moderators - 12/8/2003 11:17:18 PM   
dick Hanson



Posts: 10203
Joined: 12/12/2001
From: slc, UT, USA
Status: online 		I guess my explanations make no sense to those who have not built/ experimented with models at the extremly low weight / slow speed end of the spectrum .
I do understand that .
My reason for the seemingly absurd comments about weight and balance -are simply to give some other lines of thought -
I am oft times put off by answers given to novice modelers -when they ask about why their model snaps out on application of elev - etc.
I see formulas and answers which may be of importance on some full scale stuff - but on these small models - the real reason is simple and direct - the durn thing is too heavy -.
One can speculate on airfoils/ cg's etc.. which are less critical etc--but on the models - the real culprit is --99.99% of the time - simply weight .
if the weight is low enough - the cg importance is greatly diminished.

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