longeron material

[kepEZ]

I know it is not without its reasons but what is the rationale behind a spruce longeron?Is it for fighting stress concentrations? In a fully molded composite fuselage as is the case with berkut, I assume there must be alternative solutions to this.

[Spodman]

As I understand it the wood is there at least partly as a core material that won't be squashed when you put a bolt through it for mounting latches/hinges/seat belts/the step. I am sure there would be heavier alternatives, not sure why you would want this...

[Cozy1200]

I used Tasmania Hoop Pine for my longerons. It was purely motivated by price. In Australia it is an approved substitute for Spruce. To buy spruce locally or have ASS ship it over would have cost $200-300. To buy a single clean board locally: $30.

[Big Steve]

I used aircraft grade douglas fir. It is 20% stronger than spruce but 20% heavier. I had a planner and it saved my about $150.00 Build on STeve

[kepEZ]

I dont think I will access to spruce approved for aircraft structurel use, and -not being a wood expert- I wont be able to tell if a strecth of spruce has flaws that prohibits it as a structurel member. what is the longeron made of in berkut anyway?

[airnico]

there is a guy here in italy who is building a Berkut, I went to see it some months ago and I also had the same question:

what is the longeron made of in a berkut?

 

am I blind or there's nothing inside that longeron?

 

it's common with moulded parts to use an internal profile that is removed after curing but is this the case??

can anyone confirm it?