What software are you guy's using?

[rcpilot82]

Dave, I agree that the scratch build section would be a good place for the striker. The wood has been shipped today, so however long it takes to get from GA to PA it will be here. I am horrible with coming up with names so I can't be much help there. perhaps something like 3D Rampage?? I dunno.

[esc]

Rob, that's good.

"Rampage" or how about "R-Ampage" goes to number 1.

Anyone care to offer another name?

Do you think anyone would kind enough on this CAD/CNC web site to cut us a vynil logo for Rob's plane?

BTW I had just made up my mind to buy "CompuFoil3D" when I discovered it was sold in modular form. So to get the modules I wanted it was going to cost $120 instead of the $38 I originally thought. Since I will not be using the software enough to warrant that expense I went back to reconsidering "Profili."

I have just sent the programmer an email and if the answer I receive in return is satisfactory I will go with "Profili" instead. Getting a nice smooth DXF file of the aerofoils I want to use is all that is holding back progress on the new design.

Dave

[Spooky]

Dave, just curious, are planning on making your own airfoil design/modifying an existing one?
The reason I ask is, with so many airfoil's out there to chose from, you have to ask yourself, is it worth the extra effort of buying more software, learning it, and using multiple programs to get what you want? .... For me, I like the least amount of effort to get the desired results, not that I'm lazy , but lean towards the quick and easy when it comes to this hobby, probably comes from my machining days, "get the job done" type thing. Anyway, I'm not trying to discourage you in any way, I like learning new software myself, just trying to understand more of what your thought process is.

OK, I'll throw a name out there --- "The Scimitar 3D " --- don't know, it doesn't sound quite right.

Dean

[esc]

Hi Spooky,

I believe you are trying to make the name just a little bit too complicated - "Scimitar" is fine on it's own. That's a good name and goes on the list.

Anymore anyone?

No I dot not want to design my own aerofoil, as mentioned previously I am planning on using an existing NACA 0015 15% section for the wing and possibly an NACA 0006 6% for the tailplane.

However, I still need that aerofoil shape either as an AutoCAD drawing or DXF file to import into Inventor. It's the generation of those smooth accurate curves that I want to get right.

Am I missing something, do you have another way of achieving this? - if so please do tell.

Dave

STOP PRESS- I have just received some new information and instead of the 15% wing section I intended to use I may now opt for an NACA 0013 13% thickness.

[rcpilot82]

	Quote: Originally Posted by esc
	STOP PRESS- I have just received some new information and instead of the 15% wing section I intended to use I may now opt for an NACA 0013 13% thickness.

What plane are u changing???

[Spooky]

	Quote: Originally Posted by esc
	However, I still need that aerofoil shape either as an AutoCAD drawing or DXF file to import into Inventor. It's the generation of those smooth accurate curves that I want to get right. Am I missing something, do you have another way of achieving this? - if so please do tell. Dave

You just draw the airfoil in inventor, by either copying off of a pic of the airfoil or import a pic into CAD and make a sketch off that... and I use splines, not curves to make the airfoil shape, which allows me to smooth out the splines if I'm not happy with the airfoil shape I've drawn... I'm not sure what the command for that is in inventor, but in SolidWorks it's "Simplify Spline", which basically just smooths out the spline by removing some spline points.
I guess what I'm trying to say is, it doesn't have to be perfect, you can drive yourself crazy trying... ask me how I know.

Hope that helps,
Dean

[Mithrandir]

I think I would be inclined to fatten this one up a little... as it is intended for low Rn

http://www.ae.uiuc.edu/m-selig/ads/afplots/s9032.gif

[esc]

Oops, sorry rcpilot82 I think you may have got the impression that I am thinking of changing the 3D plane - I am not. The aerofoils I am talking about at the moment are purely for my new design(s).

Spooky, I tried that with the 3D plane and was not 100% happy with the results. I have been taught how to adjust splines and test for, and adjust, curvature on complex shapes but it just seemed to me that if someone had gone to the trouble of generating a smooth shape using mathematics why approximate it with guess work?

Last night I had an email back from Stefano Duranti, the writer of Profili, and he assures me that his software generates very accurate DXF files. The price is much more reasonable than CompuFoil 3D, it is a complete program and the updates are free if you purchase the Pro version (40 Euros)

Dave.

[rcpilot82]

Ok, Just making sure before I cut parts.

[Spooky]

	Quote: Originally Posted by esc
	Spooky, I tried that with the 3D plane and was not 100% happy with the results. I have been taught how to adjust splines and test for, and adjust, curvature on complex shapes but it just seemed to me that if someone had gone to the trouble of generating a smooth shape using mathematics why approximate it with guess work? Dave.

I wasn't implying anything about your CAD knowledge or anything, just offering my own personal experience about that.... And it's not guess work if you trace or sketch over an existing airfoil... sure you can be off a few thousands of an inch, but does that really affect anything in flight on these models?... And when importing/exporting any universal type file (DXF, IGES) you loose integrity of that file around 2%, sometimes more, which usually shows up as misaligned edges, etc. , so right there your not getting that pure mathematical airfoil, but an interpretation of what the CAD program deciphers from that file, sometimes it's very close, sometimes not so.
Anyway, just throwing this out there as food for thought, and trying to save you 40 Euros...but if you feel that it's needed, don't let me influence your decision, just trying to help out is all....personally, I use 1 CAD program for everything I do and have been happy with the results, but that's me, everyone is different.

Anyway, good luck with the design and keep us posted.

regards,
Dean

[Mithrandir]

Profili has XFOIL embedded as well... you can do virtual wind tunnel analysis of airfoils

[esc]

Spooky,

Have I given you the impression that I was offended, if so I am sorry that was not my intention as I am definitely not. If I have offended you in anyway I apologise.

I do appreciate your suggestions, please keep them coming, I certainly don't profess to know it all - far from it.

One thing I must question though is this figure of 2% inaccuracy from DXF files - were did you get that from? I have never had inaccuracies in DXF files providing they were created properly in the first place.

I'll give you two examples I have come across over the years where this type of thing occured. I used to work with a guy who added bits of lines to the end of an existing ones to bridge gaps instead of using extend, fillet 0, etc. The same guy could have 42 or more of the same item stacked on top of each other and he never new how he did it! "Near enough is good enough" was his motto. Another guy I knew never used snaps to get end points, tangents, mid points etc he just eyeballed things on the screen and dropped lines in where he thought they conicided. These people are nightmares in the CAD world.

Enough of that, the real reason I called back was to say that I am starting a new thread in the CNC section on the Striker if you would care to drop in guys and leave your comments.

Regards,

Dave