SFP1,WOV,WOE FM Tool

[+Veltro2k 6,317]

You all probably heard this before, but It would be nice to have a tool where you would add some stats of the aircraft and it would create the FM. I think it would encourage more people to start models.

[+Bongodriver 20]

Bring it on, couldn't agree more

[Fubar512 1,350]

Bring it on, couldn't agree more

 

The amount of effort one must expend to create such a tool would probably be almost as time and resource consuming as was the creation of the game itself. And, it would undoubtedly still demand some understanding of aerodynamics on the part of the user.

 

 

If you really want to create an accurate flight model, do your homework. Start by performing a search at all the SF-related sites.

[Fubar512 1,350]

Sorry, Veltro. I accidentally delted your last post while posting a response.

 

Anyway, the basics of FM creation are rather straightforward. You could begin by computing the CL, CLa, mac, and Ymac (coefficients of lift and mean-area chords) values for the aircraft you're modeling. Kreelin has created a useful applet that will perform this for you. He's christened it, "AeroConvert".

 

All one needs to get started is to obtain the following data:

 

1.) The wing surface area (in meters squared)

2.) Wing chord at the centerline root (in meters)

3.) Wing chord at the wing tip (in meters)

4.) Leading-edge sweep angle (in degrees)

5.) Standard Mach level from which to derive values (TK uses Mach 0.40)

 

You then still need to figure out the drag coefficients and their associated tables, the various lift tables, etc.

 

Then comes the detective work, where you must obtain information either from flight manuals for the model in question, or from (hopefully reliable) anecdotal sources. Information that will answer questions such as these:

 

1) At what point does the real aircraft first begin to exhibit stall buffet?

2) At what point does the stall-induced drag begin to exceed lift?

3) At what point will the aircraft depart from controlled flight (with zero stores)?

 

Keep in mind that we're just scratching the surface, here.

 

PM me if you need a hand....

[+Veltro2k 6,317]

Sorry, Veltro. I accidentally delted your last post while posting a response.

 

Anyway, the basics of FM creation are rather straightforward. You could begin by computing the CL, CLa, mac, and Ymac (coefficients of lift and mean-area chords) values for the aircraft you're modeling. Kreelin has created a useful applet that will perform this for you. He's christened it, "AeroConvert".

 

All one needs to get started is to obtain the following data:

 

1.) The wing surface area (in meters squared)

2.) Wing chord at the centerline root (in meters)

3.) Wing chord at the wing tip (in meters)

4.) Leading-edge sweep angle (in degrees)

5.) Standard Mach level from which to derive values (TK uses Mach 0.40)

 

You then still need to figure out the drag coefficients and their associated tables, the various lift tables, etc.

 

Then comes the detective work, where you must obtain information either from flight manuals for the model in question, or from (hopefully reliable) anecdotal sources. Information that will answer questions such as these:

 

1) At what point does the real aircraft first begin to exhibit stall buffet?

2) At what point does the stall-induced drag begin to exceed lift?

3) At what point will the aircraft depart from controlled flight (with zero stores)?

 

Keep in mind that we're just scratching the surface, here.

 

PM me if you need a hand....

 

No Prob Fubar, as far as the wing surface,chord and mach,,no problems. as for the rest. havent bin able to find the info.

[+Bongodriver 20]

Where can we get hold of this aeroconvert? sounds quite usefull.

[Fubar512 1,350]

Where can we get hold of this aeroconvert? sounds quite usefull.

 

Either Kreelin must upload it himself, or, give me permission to do so, here at CA.

[+kreelin 2]

....or, give me permission to do so, here at CA...

 

Go for it Ed As I did it for AIRTEVRON guys (the first and the last FM makers team) I didn't write any docs on how to use it

[Fubar512 1,350]

Go for it Ed As I did it for AIRTEVRON guys (the first and the last FM makers team) I didn't write any docs on how to use it

 

 

Uploaded: http://forum.combatace.com/index.php?autom...p;showfile=4932

[mustang60348 2]

Go for it Ed As I did it for AIRTEVRON guys (the first and the last FM makers team) I didn't write any docs on how to use it

 

Would you consider , putting up a simple post to explain what each input is.

 

For example

 

I know CLa (Coefficient of Lift at Alpha) <- Correct

CL (Lift Coefficient)

 

But what is GRAVITY (in terms of this program) , is it a standard value,

What about N (for calculating CL)

Edited July 25, 2007 by mustang60348

[Fubar512 1,350]

Would you consider , putting up a simple post to explain what each input is.

 

For example

 

I know CLa (Coefficient of Lift at Alpha) <- Correct

CL (Lift Coefficient)

 

But what is GRAVITY (in terms of this program) , is it a standard value,

What about N (for calculating CL)

 

First, lets start out with the CLa calculation. On the input side (Geometry/Speed), we need to input the following data in the appropriate fields. If you cannot find hard data online, measurements taken off a true-to-scale 3 view will work.

 

Geometry/Speed

 

Surface = Total wing surface Area in square meters

 

Ctip = Chord at wing tip

 

LE angle = Leading edge sweep angle, in degrees

 

Span = Wingspan (obviously)

 

Croot = Chord at wing root

 

Mach = use 0.4, the SF "standard"

 

 

 

Results:

 

mac = Mean Area Chord, output figure is used as reference chord

 

Ymac = Mean Area Chord offset to "Y" axis, figure is for left surface is a negative (-) value, for right, a positive one

 

CLa = Coefficiant of lift/alpha

 

CLa DeltaW = Coefficiant of lift/alpha for delta-winged models

[Fubar512 1,350]

Now, for your first assignment, I want the you to find the CLa, mac, and Ymac values for this aircraft. I will give you two freebies, the wingspan is 10.06 meters...you should be able to calculate the other values off that. 35 degrees is the leading edge sweep value.

 

 

[mustang60348 2]

Now, for your first assignment, I want the you to find the CLa, mac, and Ymac values for this aircraft. I will give you two freebies, the wingspan is 10.06 meters...you should be able to calculate the other values off that. 35 degrees is the leading edge sweep value.

 

I have come up with CLa = 4.03, mac = 2.33, Ymac = 2.23

 

I used 3.0 meters for Root Chord and 1.5 for Tip (based on the size of the picture and scale)

 

How close am I

[Fubar512 1,350]

I have come up with CLa = 4.03, mac = 2.33, Ymac = 2.23

 

I used 3.0 meters for Root Chord and 1.5 for Tip (based on the size of the picture and scale)

 

How close am I

 

Close enough for government work!

 

Ctip=1.684

Croot=2.98

mac=2.39

Ymac=2.28

Cla=4.004153

 

Next step (when I get a chance) applying these figures to an FM.

[mustang60348 2]

Close enough for government work!

 

Ctip=1.684

Croot=2.98

mac=2.39

Ymac=2.28

Cla=4.004153

 

Next step (when I get a chance) applying these figures to an FM.

 

 

Thanks A lot

 

Check PM

Edited July 25, 2007 by mustang60348

[Fubar512 1,350]

The Mean Area Chord (mac) value, is applied as the "ReferenceChord" , under the AircraftData header. like so:

 

[AircraftData]

ReferenceChord=2.39

 

The CLa value is generally divided by the number of main wing panels. If we simply have a left and right wing, we would divide the value by 2, the result being a "CLa=2.002" statement for each wing.

 

As most models have four wing panels (left and right inner & outer), we need to divide this value by 4. I personally (and arbitrarily) apply 60% to the inner wing panels, and 40% to the outer panels, so 2.002 x 0.60 = 1.2012 inner, 2.002 x 0.40 = 0.8008 outer

 

The Ymac value (2.28 in this case) is ideally applied whole for each wing, locating it on the "Y" axis by denoting a negative value for the left wing (Ymac=-2.28), and a positive for the right (Ymac=2.28).

 

Since most models have four wing panels, this poses a bit of a quandary, should we divide the Ymac value between them? The answer is a resounding "No".

 

One solution would be to recalculate using the original Croot value for for the inner panels, and then substituting the mac value (2.39), in place of the original Ctip value. You would then redefine the wingspan as the span from mac to mac on the model. A similar operation would be performed on the outer wings, substituting the mac measurement for the Croot, and utilizing the original Ctip values, and then creating a span value as if the roots of the resultant mess were connected.

 

It's probably best to simply use the Ymac value for the inners as originally calculated, and fudge the outer wing values somewhat.

[FrankD 7]

Fubar,

 

have your methodology changed since, nearly, 4 years?

 

Also, does the arbitrary percentage you apply on the CLa fits all shapes of wing?

 

And, about "fudging the outer wing values somewhat", would multiplying it by 0.8 make sense, or at least be good enough for government work?

 

Thanks for this very useful post, all such valuable tips and know how should be collected and concentrated in a neat pdf.

Edited March 17, 2011 by FrankD