Re: [RCSE] Breakaway fuse?
>Is there any virtue to designing a fuse to break in a desired spot? How would I do that? The traditional approach to this problem is to attach the wing to the fuse with rubber bands. Other attachment methods are also useful, things like nylon bolts that break before the fuse does. You might want to look at your "landings" to see how much energy you need to absorb and where the forces are concetrated. A fuse will break typically becuase its too thin for the weight of the tail feathers -- 'T' tails are notorious for that because of the multiplying effect of mounting the weight up high -- or because the main wing is rotating around one attachment point to stress either another point or push the fuse apart when the attachment point glues to a bulkhead. One way of preventing this from happening is to apply a ring of filament tape around the fuse at the weak point -- the tape is a lot stronger than the fuse (along the direction of the threads) so it will spread the force away from the weak point and so help the plane hold together. >Is there a way to construct the fuse (basic built up balsa box with longerons on the corners of the square) You could try filling it with foam. I've had some success with lightweight fuses that tended to fall apart on landing (early HLGs were notorious for this) -- the fuse became just a skin around the foam. I've also used it on fiberglass fuses that tend to wrinkle (it also holds the pushrods in place). I've tried using Velcro as a wing attachment mechanism but I've never been able to get the alignment right -- if its strong enough to hold the wing on while flying then its strong enough to not fall apart on landing. >no matter how much I might practice, I don't see that changing. You could also beg/borrow/steal/buy a foamie to practise with. A 2meter doesn't land fast and a foamie is essentially indestructable so you can focus on the flying without worrying about what happens to the plane. I had a lot of problems learning how to land an early HLG because it used to fall apart if you didn't catch it; reinforcing helped but nothing was as effective as practicing with a plane that could hit things without breaking. Its also useful to look how the foamie's made -- you can use the taping techniques on balsa planes. Martin Usher RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
[RCSE] Breakaway fuse?
Is there any virtue to designing a fuse to break in a desired spot? How would I do that? I am scaling up a favorite, but long gone 60" to 2M. The fuselage is built up balsa. The original tended to break due to my landing style. I am reinforcing the new one from the nose to a point behind the wing saddle but at that point, the construction gets lighter. I suspect I will experience some broken fuselage landings as a consequence. Is there a way to construct the fuse (basic built up balsa box with longerons on the corners of the square) so that it will absorb the energy of a bad landing by coming apart in a pre-planned fashion so that I can simply reassemble (no glue) and launch again? Where I fly and my general lack of skill raise the likelhood of destructive landings and...no matter how much I might practice, I don't see that changing. Thanks. Dave RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
