9/27/2010

Landing Gear and Parachute Chuckers

Greetings all. Welcome to another, albeit small update on the Sled. The Summer has been full of jet meets, and Jerry and I have been on the road a ton this season. Of course that has a bearing on progress in the shop, so with the flying season now concluded I thought I'd bring you up on a couple small updates.

First up, was that I needed to retool how the gear doors are handled. On a prototype test flight, one of the larger ones was ripped from the plane. I also spotted on the video (great work by Jim Brown, by the way), that prior to the door departing the plane, both of the outer doors were being stressed so hard that they were bending outward by up to 45 degrees. See this screen grab of Jim's video showing how much pressure these doors take. They are mounted parallel with the wind, but there must a lot of pressure pushing outwards on them as well. About 10 degrees outward is normal, not what you see here.

So... Now you'll see here several improvements. All gear doors are now a laminated sandwich of several layers of fiberglass, carbon and a foam spacer as well, providing thickness to them, and in turn they are a solid 10 times more ridged. In addition, in the center, is a piece of plywood, at the hard point for the attachment. All of this was pulled down under vacuum, so it should hold it's shape properly. All hinges are not only glued, but bolted as well. You'll also see the bracket that pulls on the door to close it, has been beefed up to 4/40 rod and ball ends. I had to re-engineer some of the parts at the large angle strut area, as when the gear folds, a lot of stuff is trying to occupy the same space.

Last photo on this update is a sub assembly. This is the mechanism that I've made so far to chuck my parachute out of the plane. The parachute comes out of the top of the plane between the rudders, so I need something to toss it up and out. The real one uses a series of 3 parachutes to deploy, but I'm taking a bit simpler approach. I know that this should work, as I figured this out before, on the small Yellow aircraft BlackBird 15 years ago, and had very good results. Only this time, I'm making it more rugged and serviceable.

Head back to the Main Page