Please consult an aero engineer before starting down that path. It's extremely unlikely that it'll be that simple, for a variety of reasons.Yeah, down here it gets hot and humid so performance isn't the same as it is out west in the Sierras or up in Alaska.
I've been looking hard at the Zenith because I can pick apart the kit and purchase portions, or buy the plans and purchase individual components as necessary. This is attractive because, as TFF mentioned, the Zenith can be a bit fragile when you start slamming it down. I have an idea for the suspension based on some more modern design, but implementing it on the Zenith will be tricky. I do enjoy challenges though. I have the ability to machine my own parts, so modification is that much easier. I will be switching from a metal skin to painted carbon fiber skin. This will give me lighter weight over the aluminum/paint method from the factory and still allow me to store outdoors if needed. Plus weight saved is always a bonus.
How will you attach the CF skin to the underlying structure?I will be switching from a metal skin to painted carbon fiber skin. This will give me lighter weight over the aluminum/paint method from the factory and still allow me to store outdoors if needed. Plus weight saved is always a bonus.
I'm an engineer currently working in aerospace, so no worries on that.Please consult an aero engineer before starting down that path. It's extremely unlikely that it'll be that simple, for a variety of reasons.
I appreciate all input! It may cause me to consider things overlooked. This plane is for fun, pure and simple. I want to design my own, but want to get my feet wet building a proven platform. Articulated suspension is exactly what I am thinking, maybe with inboard shocks. I could possibly do a Cabane V style setup on the main gear similar to the popular Cub design. I need to look at the fuselage structure to really see what is feasible, because what I have in my head may not actually work in reality.With no disrespect or chastising intended whatsoever... make a realistic assessment of what your actual 90th percentile flight mission is, and build to that. If your mission really requires a heavy duty commercial grade bush plane, then buy or build one. If you are sport flying, and you want to take two people, fishing tackle, and a beer cooler for camping on a river sandbar, then the Zenith sportplane or equivalent is a good mix of high utility and low cost.
By the way, the Zenith can be tinkered with to be able to land on rougher ground. An articulated long-travel gear (Fieseler Storch, Pilatus, Just Super-STOL, et al) can be fitted to the Zenith without too much effort. Adapt the Pilatus style landing gear to the Zenith, put big low-pressure tires on it, use one of the whiz-bang modern air shock tailwheels, and you are most of the way to where you want to be
Adding carbon skins to the Zenith structure is likely going to be more problematic than it is worthwhile.
Carbon fiber (which is a composite) is pretty resilient depending on what weight of weave you use. I can use carbon/Kevlar where increased strength is needed. I have made carbon fiber structures before, so I'm not too concerned. I will probably use carbon fiber tubing (very light and strong) to reinforce where needed. And just to clarify, these won't just be panels, but a molded skin. This will reduce the hardware needed, and ounces can add up to pounds quick.I would be leery of substituting carbon sheet for aluminum without some serious structural analysis. I would be far less concerned about using thin composite (maybe Kevlar for damage resistance?) in place of fabric covering like the Scott "Ol' Ironsides." There is, of course, nothing to stop you from storing a properly finished and maintained fabric-covered aircraft outside in any case.
The carbon fiber will be attached using polyurethane isolators and washers, this will prevent the galvanic corrosion issue. Anywhere there isn't a fastener but carbon fiber could be touching the aluminum structure will be addressed as needed. As for how much, that depends on the weave I use. Since the carbon won't be exposed I can go with a denser weave. As for the weight and how many mils of thickness I will need, that will require some analysis I won't have until I get/make a model of the airframe so I can do some FEA on it.How will you attach the CF skin to the underlying structure?
How will you address the CF/aluminum corrosion issue?
How much CF will you need to match the structural properties, including the toughness needed to prevent damage due to a stone or two that hits the fuselage, of the aluminum that you will replace?
How much weight will you save by using CF rather than aluminum?