Wright Stuff B

[carneyf1d]

yea. i find carbon edged razors to be the best tool to cut with. they are really cheap, last a long time, and are extremely sharp. xacto knives are so last century.

[andrewwski]

Yep...I just use good old razor blades - used to use an Xacto knife, but I find in many situations I get more control from the razor blade, plus the blades are cheaper and last longer.

I use an Xacto knife for some things still though, like cutting ribs.

[carneyf1d]

what do you make rib templates out of? i've always tried really dense balsa, but i have a tendency to cut into the template with my sharp razor blades. Plus the rib templates from balsa are hard to get exact, i always have to slightly sand it until the curve is smooth, but this takes it away from its true camber.
Anybody have any other methods?

[GitItWright]

Rib Templates-

1/16 aluminum sheet (edge sanded and polished) or 1/16 birch ply sanded and doped (lacquer).

Molding the ribs is a more positive solution as they can be sliced to width easier and the grain follows the rib's camber. May not be a hot item for AMA indoor, but, has proven to save many airplanes in Wright Stuff. Not all impacts come from the ceiling beams. The bad ones come from elbows and forearms while standing in the inspection line.

Good Luck

[carneyf1d]

haha. that almost happened to me at 2008 nationals, i was'nt paying attention and soon my partners elbow ended up nailing my stabilizer. Luckily the plane was a tank, and the event official caught it and warned me of it in time. Thanks for the rib template advice, ill definitely try them out.
By the way, GitItWright, did i happen to meet you at 2009 nationals?

[blue cobra]

How would one, specifically me, create ribs? I'm not sure about my access to aluminium, but I can definitely get some hardwood and a bandsaw. You cut grain chordwise, correct? How do you make the shape? Guess? Print out a picture from online? What size/grain/density wood do you use (and where can I get it)? What kind of blade is thin and sharp enough to cut it cleanly? How do you get every one the same?
At least I'm thorough
Then again, maybe next year they'll slap on a chord restriction and I'll have an excuse to use the very easy laser cut ribs

[carneyf1d]

Heres a link to a simplex plotter. http://www.indoornews.com/modules/PDdow ... =6&lid=133 most ribs for the wing are between 4-6 and the stab from 2-4. type in the number you want, then print out the image. Tape the paper down to the hardwood, and with a sharp blade cut the template out.

There are 3 types of balsa grain. Depending on which grain you use, the direction of grain with respect to the chord can differ. For SO planes it doesn't matter too much about the grain, since the thickness of the ribs is big they can take some abuse, however C grain has the best stiffness for ribs.
I always buy a sheet of light density, around 5-6 # / ft^3 and lay the template on the sheet, cut the simplex. move down around .075 " and make another cut. I'd usually go with a sheet of 1/16 to 3/32 for good size and sturdy ribs. There's also another method of wetting a straight piece of balsa, bending them over a curved surface, then letting them dry. I personally think the first method is easiest.
Any blade will do, and most people use xacto. If you can get your hands on a carbon steel edged razor, you should use it. To get every one the same, make sure that your cuts are clean and consistent over the template. Also make sure your blade is going into the sheet perpendicular. Last of all, practice makes perfect. If you get a bad rib, dont be afraid to throw it out!
Lastly, laser cut ribs are nice, but buying a sheet from hobby lobby for 3 dollars can make you A LOT of ribs.

[blue cobra]

Thanks! For the foil, a higher simplex makes it harder to climb, right? But how much lift does it have relative to other simplexes? And why would have a higher simplex then? Also on that program you linked to, it says to trim off of the trailing edge to desired chord, but going from almost a full page to 6cm is a big leap; this doesn't affect it? And when you say 5-6# wood, do you mean a density of 5-6 lbs/cu. foot, or is # something else(EDIT: I just found out 5# = 5.00 > 5.99, 6# = 6.00 > 6.99)? And where can I get some C grain?

[gh]

For WS, C-grain is just ricing (meaning it's an unnecessary expense). A-grain ribs will work fine.

Anyways, I used cardboard rib templates. That worked out fine for me since I'm steady with the razor and can cut the curve freehand. The template was just so I didn't have to draw the simplex every time I needed to make a cut.

[smartkid222]

i usually cut ribs using the template that came with the zeigler kit; yes i know it's not that good but i don't like cutting ribs and i just wanna get it over with. I cut them 1/16 x 1/16, i'm thinking something around 6 #/ft^3 ish probably. Cut plenty of them and pick out the best ones for your planes.

what does anyone think about this other rib making method:
http://f1.grp.yahoofs.com/v1/ENszShMglt ... 20Ribs.pdf
http://tech.groups.yahoo.com/group/ball ... essage/798