daveyrace wrote:I had a look at the pictures posted by Stefan above from Auto Motor und Sport, very interesting to see the honeycomb structure used even with carbon structure that thin. Weight matters!
I have highlighted some parts of the pictures to show my take on this part of the nose.
http://i.imgur.com/cQpTy6T.jpg
The green section at the base of the nose is relatively thin, there to provide the nose tip area to meet regs and aerodynamics under the nose (The red bull nose tip tapers up before it meets the point of the uprights.). It may be possible for them to adjust the shape of this section to improve aero etc as it does not appear to be load bearing. It appers to have a kevlar weave for strength rather than a stiffening honeycomb layer.
The Orange section appears to be an internal structural web to increase stiffness and strength of the nose above the lower green fairing. The main stiffness of the nose comes from the top half of the nose which looks quite a bit thicker in section with deeper honeycomb sandwich.
There is a lip without chrome paint on it at the very front of the green section where the smiley
nose tip fits over.
I also highlighted in the inset picture a line visible inside the nose, taking a rough line across it as the dashed horizontal orange line. I roughly placed this on the main picture using the wing pylons to help line it up. I believe this is the start of the crash structure proper and have hashed the area it corresponds with.
Under the dashed orange line there is another line partly visible, how the crash structure joins the green section under this point I don't know/cant see so have left it blank, it may stop there it may extend down
use your imagination.
BorisTheBlade points out that the first 15cm must not absorb more than 10g but there is no minimum force. I would guess it is approximately 15cm from the nose tip to the area I have hashed in orange. And would explain the light construction of the nose tip.
Good spot on the stiffener that you marked in orange. At first I thought the change in colour on the inside was just the edge of a piece of carbon fabric, but then I saw the discontinuity in the reflection on the outside of the tip, at a very similar height, indicating the presence of a stiffer zone. Well spotted.
I don't agree that the green section is not load-bearing. I really don't see any kevlar fibres either. On the contrary, the honeycomb in this section is clearly visible in the ruptured area near the top right corner of the AMuS watermark. I think the top and bottom half of the tip have equal dimensions, also because I don't see a reason why they wouldn't have. At the front edge of the bottom section no honeycomb is visible but this is probably the same on the top. The reason is it is difficult to incorporate honeycomb in a section with high (double) curvature, like the very tip of the nose.
In fact, the presence of the stiffener you spotted is the best proof that the tip does carry some load in case of impact. The stiffener prevents the sidewall of the tip from buckling as a whole, keeping deformations more in-plane and increasing energy absorption. Don't be distracted by the low thickness of the composite facesheets. It is not difficult to design a 2mm thick CFRP plate that has a maximum compressive load of 1000N/mm. Of course this is an impact structure so it is designed to fail at a much lower load but it doesn't mean it does nothing.
I agree that it is kept very light though (mass very far away from C.o.G. so it adds a lot to yaw inertia) and in higher speed impact the part starting at the FW mounts will do most of the work.