Composite Wing Design?
08-26-2007, 06:45 PM
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Composite Wing Design?
How are all-composite wings usually constructed? Are there normally ribs inside? How are the spars integrated into the skins in the JL or SM F-18 for example?
08-26-2007, 07:05 PM
#2
RE: Composite Wing Design?
There are ribs in there for sure! Just look inside a kingcat wing, Lightning wing, composite or regular bobcat at your next rally. Even my trusty old Eurofighter has ribs.
An empty composite wing would do nothing for you, the only advantage to composite wings (Kangaroos, rookie's etc) is that you don't have to sheet anything, glass etc, in order to get a good paintaible surface (or painted in the mold), and they are strong and less weight than other traditional methods.
Plus, I have found if you ding them, plug the ding with balsa, or even just hysol it and tape it over, and you are good to go!
An empty composite wing would do nothing for you, the only advantage to composite wings (Kangaroos, rookie's etc) is that you don't have to sheet anything, glass etc, in order to get a good paintaible surface (or painted in the mold), and they are strong and less weight than other traditional methods.
Plus, I have found if you ding them, plug the ding with balsa, or even just hysol it and tape it over, and you are good to go!
08-26-2007, 07:30 PM
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RE: Composite Wing Design?
Thanks Sean. What about the integration of the spars into the wings? How do you know a good composite layout when you see one?
08-26-2007, 07:42 PM
#4
RE: Composite Wing Design?
Depends on how you are defining "good".
So far, every ARF or Kit I have seen has had an adequate wing design, else you would be seeing jets fall out of the air due to a spar, rib, wing, failure of some sort.
The megabar jet I recently made is capable of 40 + G's in theory. I regularly pull 10 g's on it, and those that have seen it fly can attest it is one strong airplane. It is sheeted foam with glass. My personal lightning, I have not pulled on it that hard yet, but have seen other lightnings pulled harder than I pull my Megabar, with no issues at all. My kingcat, I'd pull so hard you would think the wings would come off, and it never even grunted.
Do you have a particular concern? Spars are usually tube spars or blad spars. I have seen no strength difference in them in our application. I have a titantium spar system here in Austin that is really strong, light, and small. Have not built it into an airplane yet though.
So far, every ARF or Kit I have seen has had an adequate wing design, else you would be seeing jets fall out of the air due to a spar, rib, wing, failure of some sort.
The megabar jet I recently made is capable of 40 + G's in theory. I regularly pull 10 g's on it, and those that have seen it fly can attest it is one strong airplane. It is sheeted foam with glass. My personal lightning, I have not pulled on it that hard yet, but have seen other lightnings pulled harder than I pull my Megabar, with no issues at all. My kingcat, I'd pull so hard you would think the wings would come off, and it never even grunted.
Do you have a particular concern? Spars are usually tube spars or blad spars. I have seen no strength difference in them in our application. I have a titantium spar system here in Austin that is really strong, light, and small. Have not built it into an airplane yet though.
08-26-2007, 07:57 PM
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RE: Composite Wing Design?
Sean, yes I had a particular concern. I drove down to San Diego to look at Shawn's new Yellow F-22. I think its their first composite wing, and I didn't notice any carbon cloth in there. Don't get me wrong, it looked incredible, but the wing is very light with two blade spars. I have the F-15 which has a foam wing, but there is a lot of carbon cloth under the balsa skin. I'm interested in the Raptor, but I'm a little nervous about the wing.
08-26-2007, 08:10 PM
#6
RE: Composite Wing Design?
There are many many composite layouts for different applications. Believe me, even if there is no carbon fiber, I'm sure their wing is strong enough to handle anything you can throw at it. There are situations where a little bit of carbon fiber goes a long way. On the hatches of my megabar, they are laid up with one layer of 6 ounce carbon fiber. Really strong, really light. Two layers of 6 ounce glass would have done exactly the same thing. Just a little bit of a possible weight penalty.
The guys who lay up airplanes aren't perferct, but most have been doing it long enough to know what work. I'd trust yellow with my money. But no offense, Raptors are FUGLY!
The guys who lay up airplanes aren't perferct, but most have been doing it long enough to know what work. I'd trust yellow with my money. But no offense, Raptors are FUGLY!
08-26-2007, 09:10 PM
#7
RE: Composite Wing Design?
Sean,
Fugly, huh? You know, I have to admit--I never liked them much until I saw the Discover episode about them. Something about that performance grows on you. I also like the high-speed bay doors. I didn't realize how huge these planes are until I saw that video. Now that I have this kit in front of me, I love Raptors! Anyway, thanks for the vote of confidence.
GW,
So that's why you were staring at the wing for so long! LOL, I wouldn't worry too much. Your F-15 wing feels a lot heavier because it is! It's got that big fat spar, foam core, lots of hard balsa, etc. This F-22 wing is built to the job. One of the things you have to remember is that Charles is a Ph.D. in Aeronautical Engineering. He knows what he's looking at when he's looking at the insides of this wing. There are two metal spars, of which the rear spar extends almost the entire length of the wing. The metal spars are encapsulated (with epoxy and steel bolts) in a hardwood box which is interlocked into several ribs under the skin. The skin is glass on top of balsa on top of multiple layers of glass. The framework underneath it is all interlocked spanwise and chordwise. It ain't goin' nowhere.
I'm glad you asked in here.
Fugly, huh? You know, I have to admit--I never liked them much until I saw the Discover episode about them. Something about that performance grows on you. I also like the high-speed bay doors. I didn't realize how huge these planes are until I saw that video. Now that I have this kit in front of me, I love Raptors! Anyway, thanks for the vote of confidence.
GW,
So that's why you were staring at the wing for so long! LOL, I wouldn't worry too much. Your F-15 wing feels a lot heavier because it is! It's got that big fat spar, foam core, lots of hard balsa, etc. This F-22 wing is built to the job. One of the things you have to remember is that Charles is a Ph.D. in Aeronautical Engineering. He knows what he's looking at when he's looking at the insides of this wing. There are two metal spars, of which the rear spar extends almost the entire length of the wing. The metal spars are encapsulated (with epoxy and steel bolts) in a hardwood box which is interlocked into several ribs under the skin. The skin is glass on top of balsa on top of multiple layers of glass. The framework underneath it is all interlocked spanwise and chordwise. It ain't goin' nowhere.
I'm glad you asked in here.
