Wing Spar Construction Materials

What are the best materials for spar construction in a built-up sailplane-style wing? I've seen a lot of designs that use spruce or basswood spars with a thin sheet of carbon fiber laminated to the top and bottom of the spar. Why not skip the wood and use just carbon fiber? If the wood helps, then fine -- I just want to know why.

I've also read a lot about sheer web materials, with the de facto consensus seeming to be that balsa is generally OK. Are there materials that offer better strength to weight for this application?

Thanks,
Cory
View complete forum thread


Related threads

Discussion *need help shaping balsa wing spars*

... steam or hot water to help pre-form a piece of material. To be more specific, i just finished framing my first wing hafl. It went together well except for at the outer tip of the wing where the main spar must be bent up to contact the outer wing rib. http://manuals.hobbico.com/gpm/ ...

Discussion Micro Mach One Build Thread - Molded Balsa Tutorial

... Classic Pattern plane, the Mach One by Norm Page. This one will have similar wing area (100 sq in), similar target weight (100-120g), and similar power (UMX Beast components). I'm doing it in the Builders Workshop because the construction technique for the fuselage is one that's not ...

Spar Construction Suggestion?

... scratch building and I have reached the point of constructing the spar. I have searched and read ... term. I was considering 1/8" plywood forward spar with carbon or bass laminate ... with similar caps. The only other issue with this wing is that the spars did not show through the fabric on the full scale ...

Discussion Advice on wing design and materials

... progressed so now I need to sort out the wing. The bits I'm not sure about are - 1. Spar sizes and type of material? ... section be strong enough? Do I need to put in extra strengthening? I've had a few wings fold on me and I don't want it to happen to this one. I've attached a few pics ...

Question Wing Spar joiner on tapered/swept wings?

... sweep. I am using basic d-tube construction, and I am at the point of figuring out how to have a strong yet light joiner between the two wing panels for the spars. The angle between the two spars is about 176.9* (each spar is swept back 1.55*) Does anyone have any ...

Butt Joints

... have received some great ideas and advice etc. This is my first call into the builders workshop. I would like some advice from experienced builders ... the joint, bolted flanges? Also what about penetration into the material - would you take something from each joint face back into the polystyrene - ...

Questions about 6' telemaster build and wing design

... other direction? The wing is of D tube construction, with 3/32" sheet balsa on top and bottom, forward of the spar, and ... one spar on the top and one on the bottom. Will this be strong enough or should I replace them with spruce spars? Also, they plans specifically say that there is no dihedral brace ...

Kit Build -- Slight warp in wing spar

... I'm building a Goldberg Super Chipmunk kit. I'm starting the wing now and the main spar has a slight bow in ... I assume this is not a big deal -- that the structure of the wing once it's all put together will be straight. Am I right about this, or should I try to get the warp/bow out ...

Material Properties of Wood

I started collecting data on the material properties of Balsa. I was expecting different values because ... me what the typical density of the wood they sell is. What other materials are lightweight and strong? Thin aluminium I-Beams whould be nice for a wing spar. I think s[ruce and birch are used in ...

Material Selection.

... wingspan. I have found a laser cutting service and now need to select my materials for the ribs and formers. Can anyone advise me as to whether I should use Lite ply or birch ply for these. I am also wondering what type of wood to use for the wing spars? Thanks Twopper

Glow Planes / Thick Wing Observation

... greater than the glow planes I've surveyed. Yet the construction techniques I found on the glow planes ... the complexity of composite. However, strengthening wing spar caps with carbon ... laminates can easily be accomplished with thin wing section. I would think therefore if these planes are redesigned ...

Apply CF Ribbon to Wing Spar

... about 6 inches of the CF ribbon for the wing. (Building QuickFlick 2 / QF2 -- DLG) There is CF ribbon on top and bottom of the spar, I have enough to cover a full side (top or bottom) and then come up short about 6 inches on the other side. Should I: ...

building boards ?

... thin pins bent and the thicker ones split the wing spars and firm balsa, so after some yrs off i will be building again and was wondering what i can use that is more builder friendly that the thin pins will go in with just a light tap. I see in the Mc Master ...

Reinforcing Balsa Spars with CF Tape

I have some Dave Brown carbon fiber tape that I plan on using to stregthen some balsa wing spars. The instructions say to apply the tape to the top and bottom of the spars. Wouldn't it be better to apply the tape to the vertical surfaces of the spars? It would ...

Composite Wing Spars

... on a mailing list where the carbon-fiber spar caps weren't staying glued to the webs. ... round the edge corners slightly. Then wrap the spar thoroughly with Kevlar©, aramid, Dyneema, or some ... , low-stretch fiber. A tight, even and complete wrap is critical to keeping a spar from separating under loads.

48" Hardwood Spars

I'm involved in a club build of a Mirage Sailplane. And the materials list calls for some hardwood spar material in the following dimensions. 1/8 x 1/8 x 48 Hardwood 1/8 x 3/8 x 48 Hardwood Does ... checked Wicks Aircraft they have 1/8" Spar Cap material which might work. Is anyone familiar ...

Building table in Workshop...

Not sure were to put this so I picked "The Builders Workshop".. I am building a work table to start building planes so I wanted to check to see what everyone else was using.. I have three cabinets that are going to be the base. I may build the ...

Scratch building Grand Esprit wings

My winter project. Have question about spar construction. I'm thinking about two different spar configurations. 1. carbon fiber sandwiched with spruce/bass? What thickness is needed? 2 carbon fiber w/o spruce/bass? What thickness Plan on 3/8" width with full depth 3/8 balsa filler. Thanks Stan

Super Sportster 20 Kit - Joining Wing Halves

... kit last night, and I have some concerns with the method of joining the wing panels in the instruction manual. They call for the two panels to simply be glued together at the #1 wing spar, then epoxy resin/ ... epoxy plywood "dihedral braces" between the wing halves (no fiberglassing). This makes ...

Re-positioning of spars

I have a kit for a Harvard that has a fixed undercarriage, it is 67" wingspan so during the build would like to put in retracts. This means moving the lower wing spars. What is the best way of doing this?

Painting over Polyurethane...

... is my first journey into the Builders Workshop, so forgive me if this is an age-old question that's been answered many times here ... successfully used a water-based polyurethane to finish off the wings, but little has been said about color. Now for the question: If I use a water-based polyurethane ( ...

CF on spars

Recently I asked a friend about putting CF on wing spars. This is for sailplanes. He said that the CF goes on the bottom of the spar only. The reason being that CF is only good under tension, not compression. If the plane was aerobatic, sure, put it on top too. Looking at the threads in RCGroups ...

Which Airfoil Design Software Is Easy and Inexpensive?

Hello, I am new to the Builders Workshop. I want to design an RC aircraft and I would like to use a simple software program that I can design the wing, choose or create an airfoil, and print out my results so that I can use each rib diagram as a template to cut the ...

Carbon Spar Sources?

Where can I purchase carbon tubes for use as wing spars? I have used arrow shafts in the past but my current project requires a spar .375" OD X 44 inches long. Arrows go up to 33 inches. Golf club shafts are longer but tapered. I don't want a tapered shaft. Anyone? Thanks!