The hairs on my chiney, chine, chines..

First, here's the finished nose section using my technique:

[photo not recovered: 40e8bb2d5f95bba0.jpg]

Before I arrived at this technique, I researched the internet and found some pretty nifty methods for interpolation, many associated with "morphing" animations. But believe me, for drafting, as graphical methods, they are all extremely tedious (translation: LOTS of construction lines!).

[photo not recovered: 40e8cd96712ec051.gif]

So, after some experimentation, here's a reasonably straightforward graphical method I used. First, I use my circle drawing "direct measurement" technique to transfer the top view fuselage width measurements to the side view, as circles. These are MOVEd, so that their quadrant points coincide with the upper and lower edges of the fuselage cross section. I also draw vertical lines from the quadrant points between the two circles, which provides an outline of what I might use for a typical fuselage cross section, without chines. The maximum width measurement is transferred using the same technique:

[photo not recovered: 40e8bcde61256312.jpg]

Next I use the AutoCAD object snap to tangent feature to draw some straight lines from the outer perimeter edge of the chines tangent to the top and bottom circles:

[photo not recovered: 40e8be9762b7986c.jpg]

Now by drawing these two construction lines, I have established a line that I can use as a length for a radius of curvature. So I use the object snap to draw that circle, and MOVE it so that its bottom quadrant point is on that intersection:

[photo not recovered: 40e8d20b752eae40.jpg]

That diagonal line is an actual radius for the circle, which establishes my arc - it's the radius of curvature.

[photo not recovered: 40e8bf9a64179e8c.jpg]

Now, the next part I didn't like so well, because it lacked *precision*, that is, I couldn't find a way to use the object snap to rotate this circle (around its quadrant point on the apex of the chine) to where it exactly intersected with the perimeter edge of the "unchined" fuselage section. I did the next best thing, and zoomed in very close, turned off the snap, and manually positioned it:

[photo not recovered: 40e8cbd06f277560.jpg]

(I just know there's an AutoCAD guru out there just laughing himself silly because I didn't know how to do that..)

This process was repeated for the lower chine surface, and I removed the construction lines, and used TRIM to clean up all the arcs, then I used the OFFSET command to draw the inner perimeter, 1/8" away. More trimming and cleanup..

Anyway, you can see the results, I think it worked pretty well. It remains to be seen whether or not it actually works out for templates, and I have a much more difficult interface problem to solve with the wing and fuselage. That's the next idea.

Oh yeah, I know that it doesn't match the magnificent SR-71 shape, but I had to make some compromises (like an engine, prop, and spinner in the nose!). Besides, the SR71 is just an inspiration for the Stealth fuselage..

[photo not recovered: 40e8cea972305bdc.jpg]

So, it's something to do! Happy 4th, everyone!

[photo not recovered: 3e69bb3870f12ad5.jpg]

"July 4. Statistics show that we lose more fools on this day than in all the other days of the year put together. This proves, by the number left in stock, that one fourth of July per year is now inadequate, the country has grown so." -Mark Twain, from Pudd'nhead Wilson

Tim

[photo not recovered: 3e69bb3870f12ad5.jpg]

"Of course there's a lot of knowledge in universities: the freshmen bring a little in; the seniors don't take much away, so knowledge sort of accumulates.." -Dr. A. Lawrence Lowell

Milton Graham\Proparc

"I don't know about this tuned pipe business. I practiced on that thing until my lips turned blue, and I still can't play a stinkin note."
"Homer J. Simpson"

Are you kidding?! You could paint that thing with flat-black priner and I'd stuff a dollar bill in the intake!

We ALL want to see this one!

Bigs

" What constitutes the dignity of a craft is that it creates a fellowship, that it binds men together and fashions for them a common language. For there is but one problem - the problem of human relations."

Thanks, dear friends, for making me smile!

(One of those drawings made me think F22.. ooops.)

[photo not recovered: 3e69bb3870f12ad5.jpg]

"Beware lest you lose the substance by grasping at the shadow." -Aesop

Forgive me if you answered this before as I may have missed it. How are you going to blend the chines into the wing? The wing center looks low on your illustration.

The answer is that I haven't figured it out yet. One possibility is to move the wing up to "in-line" position. I'm not completely sure that works..

[photo not recovered: 40eb83ff4986c807.jpg]

But even if the wing is inline, the interface between the wing and fuselage is a complex one. I'm working on it, any ideas?

[photo not recovered: 3e69bb3870f12ad5.jpg]

"Doing a little work around the house. I put fake brick wallpaper over a real brick wall, just so I'd be the only one who knew. People come over and I'm gonna say, 'Go ahead, touch it...it feels real.'" -Steven Wright

Hmmm. Naw. I don't THINK SO!

[photo not recovered: 3e69bb3870f12ad5.jpg]

"Whoso would be a man, must be a nonconformist... Nothing is at last sacred but the integrity of your own mind." -Ralph Waldo Emerson