figuring out alpha 8 .par file - I'd like to adjust my models

[ggunners]

jon,

some of what you ask is explained under the "Instructions" tab of the spreadsheet.

Moment of inertia is the same concept as momentum except in a circular fashion. The more mass you're rotating, the more inertia it will have. If you want details, check into some or search the web. Friction is just the drag of the engine, more friction, more drag less efficiency. Put the number too high and the motor will not turn. I've not played with these numbers to confirm their use in the current FMS model. As always, keep a copy of your original, change some items and see how it affects the flight characteristics. Experimenting is half the fun. Here's at a NASA site that calls a moment torque.

Number of elements refers to any irregularly shaped wing or control surface. It's best to think of it as a description of wing area. Some of that is in the spreadsheet too. Just plot out any of the surfaces that use ELEMENTDATA according to the summary in the spreadsheet. An individual ELEMENT is just a collection of parameters at a specific point along the span of a surface.

Polare is the moment, drag and lift at a specific attack angle and reference by number in the surface section of the .par file. If you find your model seems a bit odd at a specific angle of attack, you may want to adjust these. So far, I've used the ones that came with the 5 planes included in Alpha8.

-- ggunners

[Squidbait]

Instructions tab? ggunners are we talking about your spreadsheet? 'cos I don't see any instructions tab, just sheets 1,2 and 3... sheet 1 has the .par file comparison, and sheets 2 and 3 are blank...

Am I missing something? ???

... or are you holding out on us? :p

[jon]

Hi

Moment of inertia is not the problem, it is the values of:
"rotation moment of inertia of the engine and prop"
as well as the "friction constant of engine" and "friction constant of engine" I don't see how to figure out.

The element was what I assumed, but the "polare" made more sense by your explanation. Thanks!

About the "instruction tab" on the spread sheet. there is none at the shaat I downloaded too.
Maybe there is an updated version?

[ggunners]

jon,

go to and click on the link called "FMS .par object position helper". It's a different spreadsheet with some more detail and a very rough spreadsheet for transforming .mqo model data to Alpha8 .par info. There are 2 spreadsheets. It's the same link 4 posts or so above this one.

-- ggunners

[jon]

[Squidbait]

Ditto for me! Thanks ggunners!

[ggunners]

All,

Have updated the spreadsheet to include the description for reading position, chord and span information directly from a rotated and scaled Metasequoia model. See the added tab for the simple worksheet.

-- ggunners

[ramestica]

[ggunners]

[ramestica]

[ggunners]

ramestica,

One good example is the Suchoi Su 26 surface 1 or left front wing. The wing is not symmetrical around the span axis (Y) because it has a flat leading edge and an angled trailing edge. ELEMENTDATA makes more sense for describing the wing than AUTOELEMENT which is used for symmetrical surfaces, even if they have sweep or dihedral.

The flying position (CG) of the wing is 0.016 -0.4 0.03, that is slightly forward from the model CG at the 25% chord, .4 meters to the left of the model CG and a span of .8 meters.

The .par file uses 5 ELEMENTS to describe the wing.

The 1st ELEMENT starts at the left edge, i.e. Y = -.80 or the negative span from CG. That number is inferred from the span. The chord at this wingtip is .2372 m and you'll see all elements have a zero angle of attack, flap depth of .092 and flap deflection of -15, so we'll repeat those numbers at the other positions along the surface span.

The 2nd ELEMENT is located at .1719 (17.19%) of .8 m span from the wing tip so that's .13752 m to the right of the wingtip or -0.66248 actual Y position. You'll see that the chord has increased to .2888 so the wing is widening.

The 3rd ELEMENT is located at .5156 of .8 m span which is .41248 from the wing tip or Y = -.38752. Chord is .3403 at this point.

The 4th ELEMENT located at 68.75% of .8m, .55m from the wing tip and Y = -.25, chord is .3667. Notice at this point the flap has stopped, that is no flap entry. I think that means it stopped at ELEMENT 3.

The 5th ELEMENT has no flap also, located at .779 of .8m, or .6232m from the wing tip, Y = -.1768, chord is .3979.

The final ELEMENT for the wing is implied based on the span of .8 meters where the 5th ELEMENT dimensions continue to the wing root.

Of course, you could approximate this wing using AUTOELEMENT.

//Fläche Nr. 1 Surface number 1, left wing
0.016 -0.4 0.03 //Position [m] (position)
1 0 0 //ex (unit vector in flight direction
0 1 0 //ey (unit vector in direction of wing span)
1 //Polare (Nr.) (polar number used below)
0.8 //Flächenbreite (Spannweite) [m] (span)
4 //Anzahl Elemente (number of elements)
AUTOELEMENT //Equal sizes
0.0 //Anstellwinkel [°] (angle of attack)
0.2372 //Flächentiefe Anfang [m] (chord length 1st end)
0.3979 //Flächentiefe Ende [m] (chord length 2nd end)
0.0972 //Klappentiefe [m] (chord length of the flap)
0 //Klappenanfang [m] (start position of the flap)
.413 //Klappenende [m] (end position of the flap = span if full length)
-15 //maximaler Ausschlag [°] (max flap deflection)
3 //Kanal (channel)

AUTOELEMENT is less accurate for this wing but would probably fly OK anyway.

Here's a quick sketch of the wing with the ELEMENTS plotted.



Hope the explanation helps.

-- ggunners

[ggunners]

I've updated my .par file surface position helper program. It now displays the associated Direct3D .x file for a given .mqo file. You can download the latest version of the mqo-browser at .

It includes the .mqo, .x and .bmp files for 4 of my models so you can play around with it.

-- ggunners

[eclipsegsxr]

Nice additions..Had to make a few changes to it again as for when you open up a file. the file name bleeds throught the scale factor box making it har to read . also added a nice F icon instead of the Program lookin one..

Other than that Nice job once again.

I'm still getting used to the Rapid-Q programing language and playing around with Edit Plus and integrating the the rapid-Q language into the Edit plus package then it is timw to really figure out the language so I to Can make A few Programs.

eclipsegsxr
Again if you'd like to see the change just ask.