Stick ribs vs. router cut--what are the pros and cons of each?

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Peterson

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I came across a set of plans that had rib drawings for stick or router cutting (Ragwing RW 20 Storch replica) and was wondering what the differences are. It would seem that stick build would go together pretty quickly once the jig was built and it would be easier to match than router cutting. The router cut seem like they would be lighter and you wouldn't have to worry about glue and gussets.

What do you prefer and why?
 

TFF

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Routed are heavier and weaker; they are faster to build, marginally. Ply will be more expensive too. If you just cut the airfoil, it's real heavy; if you cut lightning holes, many times you have to add reinforcements. Capstrip ribs are pretty easy as you need just a Zona/Exacto saw for the cap, and scissors for the ply and a simple jig. You can always up the tool anti, but it really does not take much. How fast do you need to build the ribs? A hour a day or less will yield a stick rib; two jigs will double. A month will get you a bunch of ribs if not all. If I ever build a Fly Baby, they will be ply; Pitts, Skybolts, and Starduster Toos have had options both ways. In the 70s people would go for they ply, routed; no one ever does it anymore, with those designs.
 

PTAirco

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Have to disagree with the "weaker" thing - weight for weight; maybe. Just another way of saying they are a little heavier for the same strength. I opted for routed ribs with grooved capstrips for my biplane design and I'm very happy with the choice; they are simply far more robust as far as ground handling damage goes and easier to repair if they do get damaged. You just cut out the old ribs completely and you can build the new rib in place very simply. Try building a stick rib in place on the wing. And have you ever tried scarf-jointing a little bent bit of 1/4 spruce while attached to the wing? It's a pain in the side-slip indicator.

My money goes with the routed/capstrip type - if every ounce is important, go for the built up stick ribs.
 

FritzW

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I don't think you can say one is stronger or lighter than the other. It depends on the design.

Here's a routered rib that has the same weight but is much stiffer and stronger than a comparable 1/4" Spruce stick rib. On the other hand, something like a routered VP-1 rib probably weighs 3 times what a comparable stick rib would weigh but it's one piece instead of 40+ pieces. ;)
 

TFF

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Everything has its place. Pitts are flown hard. Sparcraft wings with routed ribs tend to break if not reinforced to their service bulletin; well known problem through the years. They also weigh more, which if you are looking for performance means you are giving it up. Capstrip ones dont have the problems. These things are really only important to about 5% of builders/ fliers; the ones who will use 100% of their airplane, maybe 110%. I would not start building capstrip ribs if the plans are ply; I would have to decide if the plane is what I want to build with all its pluses and minuses. Ply might be stronger as entity; the real question is it as strong at equal weight? Weight for equal strength is the grade for everything in airplanes.
 
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TFF

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Entertainment, cost, craftsmanship.

Everyone seems to whine about cost and for want of building, but if you have to spread everything thin, cap is the perfect way. If you cant spend $250 for some cap, 1/32 ply, T-88, find another dream; as that will build you some Legal Eagle or Tailwind ribs. $10 in a Zona saw maybe an exacto knife if you dont have one, a 2'X4' of 3/4 ply and some scrap 1/2x1 trim wood and you are making an airplane. You can even put a good WW2 movie on and somewhat follow it.

$100 router with a $10 bit, some sort of router table( $30 from HarFrt) 4-5 sheets of 1/4 marine ply( low cost build assuming 4' cord)$65 each, if capped $50, table saw or at least a radial saw to cut the 4x8 ply into manageable pieces, hole saws and the aggravation, drill press would be nice but a couple of $20 Har Frt hand ones will work, some ply for a template. With all that going on, what are you really saving? Count your fingers every time you use a tool too.

To be fair, a router or an small band saw would be needed to build nose ribs on the Legal Eagle and would be nice to have no matter what. Unless you are OCD, you are not saving anything. So what if it takes 2 months to build 25 ribs if you need 5 months before your budget recovers (budget build remember); less entertainment when waiting. I like the FlyBaby; I would build it with ply ribs. I bet it would weigh 20 lbs less with capstrip. Thats a good bit of fuel or baggage if it was not structure.
 

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