Thanks Bob. Another drawing which shows the Resolved lift vector (yellow) pulling the wing forward at high angle(high g).

Didnt know epoxy is way stronger in tension.
  

Though to be fair, if the centre of lift is at 25% chord, the bulk of the lift load is taken on the forward strut, leaving only a small load on the rear. And hence a small forward component.

Bruce

Sounds like this wood really stood the test of time. Good to hear for us new builders. Did is shrink at all or any of its characteristics change?

But doesn't that still put the drag strut in compression? I'm not seeing where the drag strut is being pulled on.

timyandow - Not at all. The tail feathers and wings are still flat and true and the fuse is still straight as an arrow. All the bolt holes still align. every thing is exactly as I left 20 some odd years ago just dirty and dusty. And if you have any doubts as to the strength and longevity of T-88, you can put your mind at ease cause I can tell you first hand that T-88 is some strong tuff stuff. Even after 20 some odd years, its not hard brittle or cracked or any signs of turning lose.

Quoted from toliver66

But doesn't that still put the drag strut in compression? I'm not seeing where the drag strut is being pulled on.

Yes you are right.The Drag at low angle of attack puts it in compression.Then it acts as a drag strut but is not called as such.

  The lift at high angle of attack puts it in tension. Then its called an anti drag strut.

  

Quoted from beragoobruce

Though to be fair, if the centre of lift is at 25% chord, the bulk of the lift load is taken on the forward strut, leaving only a small load on the rear. And hence a small forward component.

Bruce

The pressures on a wing act over the entire surface and can be replaced by a single force at the center of pressure, the chordwise position of which varies with angle of attack. To get around this problem, the single force is replaced by a force and a moment acting at the quarter-chord point. The rear spar/strut has to react the (nose-down) moment by pulling down and forward in the case of the Maxes.  The airfoil moment actually relieves some of the load taken by the front spar/strut. Nevertheless, the forward spar/strut does take the bulk of the load, roughly 2/3's at high alpha, but the load on the rear spar/strut remains significant and the chord-wise component of the strut tension cancels more than 50% of the drag force.

At low angles of attack (and the commensurate high speeds), however, the greater load is transferred to the rear spar.  This is owing to the fact that the airfoil nose-down moment is dependent upon the (greatly increased) dynamic pressure.  Indeed the design case for the rear spar/strut is V_D with 1/3 aileron deflection down which is when the wing moment is greatest. Excepting maybe a dive at zero lift angle (nose 6° beyond vertical) I can't think of a flight regime where the diagonals of the drag/antidrag truss would be in compression.

The lift vectors in the above pictures should be roughly 6 times the size of the drag vectors.  Then to get the chordwise component of lift, multiply by the sine of the angle of attack.  To get the chordwise component of drag multiply the drag by the cosine of the angle of attack.  For angles near the stall angle, about 15°, the cosine is roughly 4 times the sine.

So, if drag is X then lift is 6X and
    
   6X(sin(A)) > X(cos(A))  or  6XsinA > 4XsinA  or 6 > 4

Therefore, at V_A and 4g's, a likely design case, the wing is pulled forward by the pressures on it.  Note no discussion of the strut contributions.
  
  

The lexan for my windshield finally came in.

...

Left wing is ready for final sanding and covering.

Good work, great progress.

It looks like you've nailed your wing rib gussets. Why did you do that?

Bruce

Quoted from beragoobruce

It looks like you've nailed your wing rib gussets. Why did you do that?

Thank you, and I didn't.

I stapled them in place while the t-88 set up then pulled the staples out as per the instructions. Saves a pound or two that way and no rusty staples to compromise the varnish seal on the wood. The holes left by the staples do look like nails though.

I don't like the access hole in your spar web.  Shear is highest just a few inches from that hole.  If you want access to the bolt nuts, better to cut a slot in the underside of the D cell ply.

I might have done an incorrect thing, but anyway I decided to add an RS-5 vertical to strengthen that area, to give slightly added strength to absorb a heavy landing.

Quoted from Bob Daly

I don't like the access hole in your spar web.

Then this one will probably give you nightmares.

Yeah, I wouldn't fly that.  Why didn't they drill holes in the spar caps too?  The compression ribs are no good either, they would be at least four times stiffer for the same weight if the compression members were turned 90°.

The spars on this wing look like in the Legal Eagle’s design.
The web is 1/8 in ply.

I've actually thought about doing Box Spar if I ever build again.

Quoted from Keith103

The spars on this wing look like in the Legal Eagle’s design.
The web is 1/8 in ply.

Using over-sized web material and then cutting holes in it makes little sense.  And there appears to be no engineering thought to the hole sizing or placement.  The holes might be ok near the tip and root where the loading is low but they should get progressively smaller and wider spaced toward the strut attachment point.

Quoted from Bob Daly

Using over-sized web material and then cutting holes in it makes little sense.  And there appears to be no engineering thought to the hole sizing or placement.  The holes might be ok near the tip and root where the loading is low but they should get progressively smaller and wider spaced toward the strut attachment point.

What would be your suggestion for a fix. Reenforce around the hole? Cover it with a peace of web material. I don't really need access wonce final assembly is done.

Quoted from toliver66

What would be your suggestion for a fix. Reenforce around the hole? Cover it with a peace of web material. I don't really need access wonce final assembly is done.

I'd glue in a piece of 1/16" ply over the hole with at least a 1" overlap. If you decide to keep the hole, you might do Keith's upright or use a ply doubler  or both.

how about a Box Spar Conversion?
basically glue a piece of ply to the open back.
Would that work?

Quoted from PUFF

how about a Box Spar Conversion?
basically glue a piece of ply to the open back.
Would that work?

Yes, that would be stronger than the original design.

How do you like me now?

Finished repair

Got the bottom covered today.

Finished covering the left wing.

Hello there,
Beautiful building!
Look, I don’t want to make a mess on you mind, but you made a scarf joint on the upper spar cap??? Is it safe to do that in a wing??

Quoted from raphael150

Hello there,
Beautiful building!
Look, I don’t want to make a mess on you mind, but you made a scarf joint on the upper spar cap??? Is it safe to do that in a wing??

Yes