Table Multiplication - Airfoil Chord

[Arbiter]

Hey Folks,
I am working on a design for an aircraft and I have a dilema. I want to design a tapered wing, and I have the airfoil coordinates, but they are in the natural coordinates with the chord going from 0 to 1. To get the actual airfoil size, all I would need to do is multiply by the real chord length and get a full-sized airfoil. However, I would like to do this internal to ProE if possible. My thinking was, if possible, name a parameter the chord length. Then, use a relation to somehow multiply each row of the tabulated data to get the actual coordinates of the full-length airfoil. Is this possible, and how would I do it? Thanks!

-Chris

 

[wsylvester]

one method would be to create a sec using your 0 to 1 numbers but break it into 2 parts, top and bottom.... pretty easy in the chord file to do so.


drop a csys and a horz. spline form the csys out and make len 1 and vert. zero


hightlight the spline rt click to get to modify menu<WF2> ..pick the file menu top left crn. and then pick the csys then open your top half of the 0-1 file the open file icon should become useable once you select the csys...when it says "file conatins different number of points ? contine yes you shaould have something that looks like this .. this is a C-141 profile








do the same for the bottom


if you got all that right then flex it, if you change it to a large number you may get some... 0.000000053539 number .. not a big deal... edit it back to 1 before you save section.








but it maintains the shape, now I'm taking it that you want to extrude this





so create a sketch that will define your trajectory of the extrude then use that with a VSS. read up on VSS, When yo get to the sketch part of the Vss ...


top menu... insert>data from file>pick your section.. change the scale to 1


right click the x in a circle on the sec and then left click it to the csys of the section it should snap to the end of the traj.... then click ok on the scale rotate box , edit the 1 to what you want it to be. If that looks okay.. then just go ahead and finish it out.. You can add the relation in by redefining. You want to go ahead and make sure you got it all right first. Scope itout .. flex it





if it looks like you want then edit defination of the Vss, go to the sketch and toggle the dims so you can find the sketch dimension value you need that in the relation


tools>relations... then whatever you want to do this will start out at 10 then reduce by 4


sd3=10-trajpar*4








ouryou can control by evalgraph if you need more variations... and if you want you can even put twist on it, few more steps in setting up the vss.


twist<relation> len<evalgraph>








just one way, there are some others


I wonder how one does this in SolidWorks?

 

[Arbiter]

wsylvester,
Thank you for the great description! I am very interested now in more detail on how to use the evalgraph for twisting the airfoil. I've never used the evalgraph relation. How is it used? Thanks!

-Chris

 

[wsylvester]

evalgraph gives you a way to have values controlled by a graph..


the placement of the sec. determines your ability to twist it, you need have a angular "sd" value to manipulate

 

[tobbo]

cool modelling, you should post it in the modelling section instead of drawing.

//Tobias
Edited by: tobbo

 

[wsylvester]

the topic started here , just showing a method.


So the biggest hassle really is getting the section hooked to the angle dim in your vss sketch. If you get a ref dim then you're not there.


Also one of the things about evalgraph is that you want your traj. len to jive with the x_length in the graph and the evalgraph function in your vss relation.


So part parameters are a good way to go. That also allows you to mod things without having to go 3 picks into the vss edit def. Sometimes you have to edit def. it to get the changes from the parameters depends on how you set your math.


One way around that is to have some parent sketch geom. to mod dims with, that way they regen prior to the vss and force it to update... if that makes sense

in the graph;


the part pram. tl is used to control the length of the vss traj. and it is used to control the x_len of the graph above sd1=tl.... sd4 is part pram. ang.. the angle


that way I don't have to edit the graph I can edit parameters. One thing you can't have in a graph is a vertical line!! and you also can't have it create zero length lines or zero rads/dia... it have to create real geometry sd8 is just a regular value.





so the angle goes up then back down..by the function


sd12=evalgraph("g2",trajpar*tl).... sd12 being the angular sd dim in the vss sketch


g2 being the graph made prior to the vss.... tl being the traj len & x_len val .. if they aren't the same then it either is not complete along the traj or does it early.


It's like a time function across the traj of the vss. You can get some butt ugly geom. by squishing the section, so you have to make sure you're not too radical in what you want to do. also rads help alot in transitions


The sketch line at the trailing edge is just to show the displacement.


VSS is just too cool ...if you ask me

 

[wsylvester]

one other thing if you are using say a curve for your vss trag. then create a analysis feature for that length. then a part rel. to assign that value to a parameter, with ....myparm= length:fid_analysis1





then you can us that "myparm" in your graph for x_len, that way when you change the traj. it will update your graph value and express it along the whole length

 

[wsylvester]

provided you have the config option to allow analysis features turned on

allow_anatomic_features YES

 

[Jacoolo]

search through forum for Jeff4136`s posts

there is a lot regarding air foil profiles

btw

Jeff where Are You?