Joined: Jul 20, 2004 Posts: 3702 Location: Birmingham, UK
Posted: Tue Jan 09, 2007 7:53 pm Post subject: Robinson Posts Blade Skin Debonding Safety Notice
RHC has received reports of main rotor blade skins beginning to debond (separate) at the skin-to-spar joint on the lower surface near the blade tip of R22 and R44 blades. They are recommending thorough visual inspection... Read the full documentation for more info:
Joined: Feb 14, 2008 Posts: 888 Location: Stavanger, Norway
Posted: Thu Dec 18, 2008 9:55 pm Post subject:
So has anybody got experience of the Airwolf kits for thr Robbo's? Any improvement seen? It got me thinking about the Robbie blades when I was taxiing out the other morning and you could see the de-icing sand/salt sparking as it hit the blades.
Posted: Fri Jan 08, 2010 8:57 pm Post subject: Can tape prevent disbonds?
Blakmax here. I have posted extensively on that other forum in relation to adhesive bonding. I have 37 years experience in that technology and I specialise in adhesive bond failure forensics. I have examined failed RHC blades and I observed extensive adhesion failure (a weak form of failure which occurs the interface between the adhesive and the metal) and only limited cohesion failure (fracture of the adhesive layer). Adhesion failures are time dependent and are usually driven by hydration of the chemical bonds at the interface. They are directly dependent on the processes used at manufacture and the rate of failure increases with humidity and temperature. Atmospheric humidity is sufficient to cause the problem. Tapes and paint will only slow down, not prevent moisture diffusion so they do not prevent the problem. Worse yet, the best defence against this problem is visual inspection for lifting of the skin. If you place a tape over the joint, how do you inspect it?
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