[betasniper]

Originally Posted by aerohead

I would compare it to Mair's boat tail.
He used about one body diameter length to curve his body into a 22-degree slope,and then just maintained a constant slope as in your rendering.
The 'straight' conical sections are easier to fabricate but must be reinforced from the inside,as they have no eggshell strength of the compound curve and will 'tin can'.

Yeah, It was about a 15° angle at the end for that one because the thickness was only 35% (Eppler 863). I posted that airfoil because that was the largest symmetric airfoil I found in that database. There is a very slightly unsymmetric airfoil which is a 38.8% thickness (Eppler 864), but even that one only goes to an 18° angle.

I put the AST-2 Template into Solidworks and tried as best as I could to make a simple spline fit the Template but These are the angles I got:

Largest deviation (angle wise) was the very first angle with a 1.3° discrepancy. Everything else is within .4°. The grey dimensions are driven and Σ's are equations. Only the black Numbers without Σ can be altered (The 500 and the 23°). The blue lines above the spline represent the curvature. Bigger lines means more curve, Smaller lines means flatter.

Edit: Even though the angle discrepancy is large, the spline I drew was slightly slower curve than the template. Very slight.

Percentage
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%



X
0
172
344
516
688
860
1032
1204
1376
1548
1720



Y
500.00
488.92
461.69
423.61
377.54
325.23
267.81
206.09
140.62
71.81
0



Angle
0°
6.8°
10.9°
13.9°
16.0°
17.7°
19.1°
20.3°
21.3°
22.2°
23.0°