Flying Wires vs Struts

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TFF

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I think of it as an AD. You are looking for number of frayed wires or slipped crimps which is impossible today if they did not document it directly. Just like a parent, they said stop. Just like wood spar airline planes and Knut, just not as famous. Aviation was becoming big business and they did not want to deal with it. I’m sure someone at The Aerodrome knows, and I bet it is laziness crossed with stupidity like most of these things.
 

pfarber

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Also the attachment points are very messy and require fussy little asimetric fairings. Struts have half as many attachment points as wires.
THIS. Struts can be used in compression and tension... wires not so much. Also wires can stretch and need adjustments. Struts... are just bolted on. Also corrosion, and simply more parts for wires.
 

challenger_II

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Jul 15, 2009
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Fisher County, Tx. USA
Part 103 bird. The reason behind my original question was to balance drag, and weight.
Owning a Starflight TX-1000, I am well aware of the complexity (read: pain in the neck) of
dealing with multiple wires, and, having owned a couple of Challengers, am familiar with
the relative ease of assembly.
For my "clean sheet of paper" bird, I was attempting to get "real world experience" on
the drag comparisons.

What kind of plane? If you are trying to go fast, go with struts. If you are a slow Part 103, wires can ba lighter and provide more rigidity for a lightweight frame. When flying something like a Quicksilver, I value the slow speed flight, so wires are fine. When it comes to easy disassembly though, struts can be a better choice. Depending on cockpit access design, struts might provide easier access for ingress and egress.
 

Geraldc

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Nov 12, 2011
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nz
If you are designing for wires then why not tension members in modern materials with an aerodynamic cross section.
The size of the struts is to handle compression loads.
Another option for streamlining wires is Pops balsa idea but with heatshrink covering.
You can buy heatshrink in rolls now.
 

Norman

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If you are designing for wires then why not tension members in modern materials with an aerodynamic cross section.
The size of the struts is to handle compression loads.
Another option for streamlining wires is Pops balsa idea but with heatshrink covering.
You can buy heatshrink in rolls now.
Pulltruded rod could easily be made with a strut cross section but end fittings are not avalable so you would have to design, fabricate, and test your own. Could be done but it'd be time consuming.
 

kubark42

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Oct 19, 2020
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As others have pointed out, the tradeoff between weight and aerodynamics is largely a function of airspeed.

If money is no object, then flat wire is probably the best bang for the buck. Not quite as aerodynamic as a streamlined tube, but it weighs much less.

If you are designing for wires then why not tension members in modern materials with an aerodynamic cross section.
If ultimate weight is the goal, then dyneema is a possible option. 4-6 times lighter than steel for a given strength, much cheaper to manufacture, and much easier to work with. And it isn't fragile like a pulltruded rod, nor does it corrode like steel. The disadvantage is that it's wider than a steel rod, so you'll have to either accept the drag hit, or figure out how to fair the line.

For the speeds you're looking at, it's good to compare to racing sailboats. The fastest production sailboats use dyneema for their rigging, because the increase in diameter is well worth the decrease in weight. The fastest custom sailboats use carbonfiber rigging, but those need to be babied because impacts will degrade the rigging.

And the fastest single-use boats (think America's Cup) use exotic materials which don't survive more than a few hours in the sun, so that's not really an option for you I bet. :D
 

Aesquire

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Jul 28, 2014
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Rochester, NY, USA
Wire braced wings fold just fine, you just need different technique. Not very different, you still need to make sure you don't pinch stuff or get brackets rotated wrong that can bend stuff, with struts.

Streamlining wires that are not rigid, and need to be rolled up when you fold the wings is really hard. If the streamlining isn't aligned with the air flow, you get drag from the lift they produce, as well as parasitic drag, and if one end of the cable has the fairing "up" and the other end "down" you can get wild vibes. Not worth the bother IMHO. It's different in, say , a Biplane

Comments about number of intersections to fair, are true. Also no wires means no king post. Weighs more though. A lot.

For a pt 103 craft that is so weight limited, and speed limited, wires work fine. Just like the Kolb Firefly uses twin struts to add drag, the rare overpowered "Ultralight" actually can benefit from wire bracing.

If I had to chose between 50 ponies and wires, and 30 ponies and struts? Give me the climb rate!

I've made the joke before, but it's not really a joke. Your pt 103 new toy is too fast? Add wires.
 
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