brand new outer ribs from my new shop--- finally

[fairchild1934]

here are some new ribs----

brandnewribs.jpg

[BravoGolf]

Those look very well done.

[fairchild1934]

pressed on the 30ton press using a 4 inch thick rubber pad ! Couldnt ask for better ! :-)

[Bcone1381]

How much time do you have into pressing one blank into a rib?

[fairchild1934]

well- from scratch----- about 5 min cutting the raw material out with a pneumatic body saw. about 20 min marking and drilling the registration holes.
about 15 min to rough-punch out the lightening holes------about 10 min to route the edges to their final size on the router table and about 30 min to do the pressing. and about another 30 min to manually finish the outer edge bends and fluit and straighten. so thats about 90 min or so--- But once I get going----- I run 4 or 5 pieces through each step together. I cut out 5 blanks. Then I pilot hole all 5. then I punch all 5 --- ect. That cuts off about 1/3 of the total time. The rubber works great. I have the wood cut on a 45 on the lightening holes and the rubber bends it to 30. They are nice and even and I dont have to touch them with anything. ( I tried the bob-stick early on and it just made a lumpy , uneven mess-.
i use 2 rubber sheets- each 2 inches thick. I think if they were a little lower durometer I could get the outer flange closer to 90 degrees during the pressing.
as of now I get it to about 60 degrees. The rest of the bend I finish with a rubber dead blow mallet.

The tip rib is longer-- so I think that means I have 18 of these to do. so I hope to have all 18 done in about a week.
i have 5 of the 10 center ribs all ready done.

I suppose I will lay my master rib down on a piece of 2 x 10 and make a forming tool that way for it.

Tim

[fairchild1934]

I was noticing that the flap spar is like 8.6 feet long. Wondering why it wasnt 8 foot- to match raw material. (and an 8 foot brake) I wonder if that was driven by where the flap bell crank had to be mounted--- which would have to match the center point of the flap .

[Bcone1381]

I think your rubber press method probably produces a ribs that is flat rather than potato chipped. I pounded out a set of ribs once upon a time using a dead blow hammer on a airfoil shaped buck. I spent about 30 minutes changing the look from a potato chip into a rib after flanging the lightening holes.

[fairchild1934]

yes--- my nose ribs had some potato chip shape --- not so much these bigger ribs. dont know whats different----
maybe the very steep curve on the nose ribs was causing some of that shape. I was able to get it all out of the nose ribs ok though......
they are all dead flat now.

[fairchild1934]

correction ---- the center ribs come out with a slight bow in the vert. direction - but that will be straighten out by the stiffeners.
the curl in the other direction (nose to tail) that all gets leveled out with the fluting . You just lay them down on the flat bench and push down with your finger and it either rocks or has daylight in the center. So you either slightly increase a flute or mash a little out where the bow is. You can get the flange very flat on the table that way in just like 5 min. The nose ribs didnt have any curve anywhere after straightening them. I would like to try a softer rubber pad-- if I could find one 4 inches thick. Im using all 30 tons- but I think thats because my rubber is maybe stiffer than needed.