ETLB Squawk Forums — Archive

I would know the answer to these questions if I had the outline drawn on my table but Im still working on it, the longest piece's of longeron wood I have  is 8 ft, for the top I don't know if this will put my scarf in the center of the cockpit as in the plans, is there any reason the scarf just have to be there? for the bottom I don't know if that will reach the center piece, would it be ok to scarf a piece in these if needed?

Yes, there is a reason. The scarf at the top is supported by the structure around it (the seat framing and fuselage sides and top ) and the one at the bottom is at the bend in the floor. It is also near to the centre of lift so has to carry the least weight. A look at my online plans shows that the scarf is between station 2 and 4 which is 70" back. Behind that is 8' 1 1/2" of fuselage so no. Your 8' length is not long enough. Now a good scarf is considered to be as good as the wood it is made from but these are four of the most crucial parts of the aircraft. You may choose to scarf where you will but I would go and buy a longer piece of wood.

Ok, thank you

Tail loads, air and wheel, on the fuselage truss aft of the plywood box subject the longerons to compressive and tensile loads.  The loads increase as the distance from the tail increases.  Splices in the plywood box section are reinforced by the plywood and other structure.  If you must splice the longerons in the truss section, make the splice as near to the tail as possible and reinforce the splice with 1/8" plywood plates (in addition to the ply doublers already prescribed in the plans) that extend a couple of inches beyond the splice or sister in a piece of longeron material.

are you sourcing your own wood? if so hit the lumber yards with the AC on wood grading in your hand and look for douglas fir flooring. pick out a board that makes the grade and is long enough to not need a scarf joint.

Thanks Ace, I don't trust my judgement picking wood for this purpose, since Wicks is only about 70 miles from here I think Ill just drive down there and pick up what I need for the top rear, what I have should be long enough for the rest, shipping for piece's that long will cost more than the wood itself

Quoted from sbank1957 Thanks Ace, I don't trust my judgement picking wood for this purpose, since Wicks is only about 70 miles from here I think Ill just drive down there and pick up what I need for the top rear, what I have should be long enough for the rest, shipping for piece's that long will cost more than the wood itself

that is a great option too. good luck and keep us posted on your build

Agreed. There is nothing like using the right stuff to make you confident about the build quality and you need that when your work is all that is between you and a thousand foot drop.

Quoted from sbank1957 Thanks Ace, I don't trust my judgement picking wood for this purpose, since Wicks is only about 70 miles from here I think Ill just drive down there and pick up what I need for the top rear, what I have should be long enough for the rest, shipping for piece's that long will cost more than the wood itself

Are you able to source spruce at Wicks via local pickup? Seems on website they are no longer selling spruce? Anyone have any insights?

If we are talking about the longerons then the recommended wood is White pine.(Pinus strobus)

There is no mention  of spruce being used in any minimax part or did I miss the briefing?