The trade publication High-Performance Composites offers this news about the development of SpaceShipTwo:
Advanced Composites Group Ltd. (ACG, Heanor, Derbyshire, U.K.) will supply a new generation of out-of-autoclave prepregs for the project, featuring MTM45-1, a variable-cure temperature, high-performance, toughened epoxy matrix developed for resin film infusion and prepreg processing. It was designed for low-pressure vacuum bag processing and, in addition to resin film and prepreg formats, is available in partially or selectively impregnated formats to reduce layup time, surface defects and internal voids. After a freestanding postcure, the system is capable of 150°C (302°F) wet Tg and reportedly exhibits good damage tolerance. Initial cure can be as low as 80°C/176°F, which ACG says allows for the use of lower cost tooling materials.
But you all knew that already.
Would it make me a tech nerd if I said this sounds exciting?
Prepegs offer (even) lower weight, higher strength, less wasted (squeegeed out) epoxy and most importantly… Can survive much higher temperatures without deforming or melting. Something to which SpaceShip2 might appreciate. The downside is that you NEED an autoclave and they don’t make those things very big… SpaceShip1 was made in small parts so it could be autoclaved but that added complexity and weight.
That material could be very useful, especially for people like me that like to do big composite projects that tend to sit in the sun (requiring white paint jobs to reduce heat buildup) and can’t afford an autoclave…
Ironic that a British company is providing new technology for SpaceShip2 while Virgin Galactic has to jump through hoops because of ITAR…