Balsa wood properties
Balsa wood properties
(OP)
Low, Medium or High density, Which types of balsa wood is most cost effective and Structurally efficient and available in market?
Is it possible to have a balsa wood block of 5ft long and 3x3" cross sectional area in market?
As this wood beam will be subjected to bending, to make it highly efficient I like to make two types of wood blocks.
At tension region Wood with strong axial fiber (A grain)
And at compression region C grain.
Then glue will be used to join them together and make them act as one single beam.
Is it a good idea?
Is it possible to have a balsa wood block of 5ft long and 3x3" cross sectional area in market?
As this wood beam will be subjected to bending, to make it highly efficient I like to make two types of wood blocks.
At tension region Wood with strong axial fiber (A grain)
And at compression region C grain.
Then glue will be used to join them together and make them act as one single beam.
Is it a good idea?





RE: Balsa wood properties
Wood is rarely mixed the way you describe. And I say rarely because although I've never seen it I can only assume one or two of the engineered lumber companies have tried something like it.
Generally you use a full spanning piece (or pieces grouped together ) and just design the length of bearing as required.
RE: Balsa wood properties
So, why do you want to use something every else even in aero fields has abandoned in favor of other material? For example, balsa wrapped wood was not often used even by WWI: Wood frames with metal clamps and fasteners and highly-doped lightweight cloth covers were more common even then.
RE: Balsa wood properties
As for the specific structural properties and types of Balsa, I would have to Google it. Even older copies of the AITC do not list it to my knowledge.
Mike McCann, PE, SE (WA)
RE: Balsa wood properties
Mike McCann, PE, SE (WA)
RE: Balsa wood properties
RE: Balsa wood properties
Mike McCann, PE, SE (WA)
RE: Balsa wood properties
I will use it for a homemade aircraft actually.
Your comments are really helpful, I like to switch myself from balsa wood to another material. Ill look for a better one. Suggestion will be greatly appreciated.
RE: Balsa wood properties
RE: Balsa wood properties
RE: Balsa wood properties
If you are building Model aircraft go to your local hobby shop and check out their stock. Talk with some of the modelers that hang out there , especially the one that build 1/4 size models.
The application used in the De Havilland mosquito was to separate plywood skins by varying degrees by stacking the wood in an end grain fashion. Balsa is quite strong in compression compared to its weight. This technique was used after the 2nd world war to build high strength to weight ratio wings for sailplanes. Later plywood skins were superseded by fiberglass skins then carbon fiber, eventually the balsa cores were replaced by foamed PVC or honeycomb. You can still buy end grain balsa block pre fitted to a very fine woven scrim from companies like Fiberlay, or Baltek , Google them. The latest modeling methods are to cut parts from foam, then cover them with a high strength material such as fiberglass or carbon fiber.
B,E.
You are judged not by what you know, but by what you can do.
RE: Balsa wood properties
RE: Balsa wood properties
Get a Rutan Vari-eze book and study what does work. The Mosquito was built by pro's after many years of failures and excess weight.
RE: Balsa wood properties
Then sandwich structure with balsa core sounds best.
Glulam beam also sounds very good.
RE: Balsa wood properties
RE: Balsa wood properties
And notably classy and expensive surfboards...
RE: Balsa wood properties
Yes I know, sandwich structure. Btw will you please suggest me any solid wood other than balsa?
RE: Balsa wood properties
RE: Balsa wood properties
Mike McCann, PE, SE (WA)
RE: Balsa wood properties
RE: Balsa wood properties
My guess is that engine technology was to blame on the lack of power side. The engines look pretty small compared with the size of the airplane, even though they are huge when seen separate. The B-36 had the same problem and had jet engines placed near the wing tips in later versions.
My sailboat has 1/2" balsa cored hull. The bending strength is in the fiberglass inner and outer skins, the balsa serves as the spacer between the skins and takes some shear stress. The balsa is in mats, cut across the grain like a checker board. In that way it can be laid up to conform to the curved shapes of the hull.
RE: Balsa wood properties
RE: Balsa wood properties
Since the core is primarily loaded in shear, the butcher block arrangement also loads the balsa in the cross-grain direction, which has a greater capacity in shear.