Originally Posted by
Carbon-Customs
ive now made a cut into the wing to have a look.
and its the same build up as the bad "hawk 1:4,5" tail
the tiny screws and the honeycomb plate (even when its made with carbon) cant take the stress.
This is a plane which in normal manoeuvres will pull about 10 g's max, (measured with my 1:5 F16 at 25kg) so if the lift of the wings is about 50% of the plane then its still 75kg of force on each wing!
i put alot of stress on the wings, and head some cracking noises...
well i think a OK fix for this i to fill the space between the rod and the sideplates is to fill it with microballons and epoxy.
i would drill about 5 times 8mm holes under the rod to be able to fill with epoxy, this shouldent weaken the wing.
i will also open the rudder, i guess its made the same way.
You guys are missing the point. The issue here is not the high loading, it's the frequency-loading combination. The test that you did is good for static stress, but the problem is that when you fly the wing tube flexes up and down, and the little screws will eventually eat into the HC spars.......even with carbon reinforcement. Changing the tube will not make things better.
Let me put it in perspective, the HC is like poop.......lets assume it is not there at all. The carbon laminate is just a thin piece of .030" rigid composite, one on each side. A thin piece of super riigid composite will crack easily under vibration, which is what is happening when you fly. How soon will it crack...........I have no idea! Every flight is a flight closer to the limit.
Kasper I see your picture and it only proves that even in the higher end products, these guys still use the methods that have proved to fail. Those two glue spots may help some, but filling the area completely with adhesive will improve things greatly (still sorry you had to cut the wing open though).
Beautiful bird in the air........Hope you guys can make it work. The fix is out there.
David