RCC Impact and the Boeing Study

From Page 8 of the Boeing Study data 1/21/2003



RCC Predicted Damage at Incidence Angles Greater than 15 Degrees Based on
Ice Database

Angle Velocity Damage Depth (in)
5 720 0.11
10 720 0.18
15 720 0.23
20 720 0.28
25 720 0.33



Size =20 x 10 x 6 Density =2.4 lb/ft 3

45 ° angle of wing was taken into account

Nominal panel thickness is 0.233 in.

RCC is clearly capable of withstanding impacts of at least 15 degrees;

relative softness of SOFI (compared to ice)would indicate greater
capability

" Maximum reported angle of 21 degrees is not an problem "

Looking at using Window ice and RTV data as an analog

End Quote.



Notice that the damage depth for 15 degree impact is 0.23 inches while the
Nominal panel thickness is 0.233 inches. Essentially, this chart say that
any impact greater than 15 degrees will fully penitrate the RCC leading
edge. An impact of 25 degrees would penitrate (0.33 inches) an RCC panel
that is 41% thicker than the nominal RCC panel (0.233 inches).

After the table shows that the RCC panel will be penitrated, a bunch of
hand waving and wishful thinking is used to make the problem disappear.

Even an impact of only 5 degrees has damage depth of 0.11 inches which is
much deeper than just a loss of the coating of the RCC panel. This table
certainly does not support the statement in Summary and Conclusions on Page
13:

"RCC damage limited to coating based on soft SOFI"

A conclusion that is not supported by the data.

Craig Fink