JayKoit
Well-Known Member
Hi Everyone,
As a follow-up to my bubble canopy thread, this is something else I've been noodling:
I was looking at the SAM Aircraft a while back and really liked the fact that it was an aluminum design with a steel cage built around the cockpit for crash protection.
It got me thinking: Could I, or has anyone ever, built a steel cage into an existing aluminum aircraft design (Zenith, Vans, Sonex, etc)? I haven't looked really hard at any of these planes' plans, but I was thinking a cage could be built from square 4130 tubing, with the tubing laid out exactly where the aluminum angle/stiffeners were, so they would essentially replace the angle and the skins riveted to that (plus any reinforcing tubes, of course)...or if lots of rivet holes weakens the tubes too much, maybe the tubes get placed in between the original angle/stiffeners, and maybe a some welded flanges serve as attach points for the cage to the airframe/skins? Here's a picture of the SAM cage, since that design has a round fuselage, they used rounded bulkheads which attach to the cage via flanges, and the fuselage skins attach to the bulkheads:
I'm sure it would be a bit of a headache, but I wonder if it's possible. And I know it would cut down on useful load quite a bit, but the RV-9 and the 650 have useful loads between 600-700 lbs so there's some wiggle room there.
Thanks!
As a follow-up to my bubble canopy thread, this is something else I've been noodling:
I was looking at the SAM Aircraft a while back and really liked the fact that it was an aluminum design with a steel cage built around the cockpit for crash protection.
It got me thinking: Could I, or has anyone ever, built a steel cage into an existing aluminum aircraft design (Zenith, Vans, Sonex, etc)? I haven't looked really hard at any of these planes' plans, but I was thinking a cage could be built from square 4130 tubing, with the tubing laid out exactly where the aluminum angle/stiffeners were, so they would essentially replace the angle and the skins riveted to that (plus any reinforcing tubes, of course)...or if lots of rivet holes weakens the tubes too much, maybe the tubes get placed in between the original angle/stiffeners, and maybe a some welded flanges serve as attach points for the cage to the airframe/skins? Here's a picture of the SAM cage, since that design has a round fuselage, they used rounded bulkheads which attach to the cage via flanges, and the fuselage skins attach to the bulkheads:
I'm sure it would be a bit of a headache, but I wonder if it's possible. And I know it would cut down on useful load quite a bit, but the RV-9 and the 650 have useful loads between 600-700 lbs so there's some wiggle room there.
Thanks!