ORIGINAL: Jeff Foley
ORIGINAL: CRG
Have to disagree here. It is very possible to produce high quality honeycomb sandwich parts at or near room temperature (100F), in epoxy molds. I do it all the time. Peel strength of the inner liner is certainly critical, and there are several methods for achieving a consistent bond without requiring an autoclave, high-temp molds, post curing etc.
In general, I'm still baffled by the reliance on structural 'strength' and high-torque servos for flutter prevention. Flutter is an aero problem, and can be largely prevented through simple measures. On a full flying surface one method would be the correct relationship between pivot, CG and aerodynamic center. No amount of structural beef will prevent flutter.
Not that I'm defending FEJ in any way, and I applaud Dave S. for standing up for his beliefs.
CRG
Agree 100% with everything said in this post. I too have been producing aerospace quality parts with room temp curing resins and honeycomb material for many years. The problem is that we have reached the point where the size, weight and performance of these models require them to be properly engineered....instead of just overbuilding or guessing that something is strong enough. I am not a structures engineer, but I know enough to know when to stop and ask one!
Ditto, Jeff and I have work on some projects together in the past and so long as a structural engineer approves the fabrication methods. A wet layup room temp structure is just fine if and thats the big "IF" they are fabricated to an engineered design taking into consideration all loads and materials used. True a prepregged bagged oven or autoclaved structre could be lighter and stronger but it still has to be engineered to work. I am not and would not ever be afraid of using honeycombed structures just because of FEJ's failure to do proper engineering to save weight, I would ask engineers who know what they are looking at to look it over for me before I built it and I would load test it like we do at work with a new design.