Aluminum Wing Structure

[JohnB]

MANY  years ago Leonard and I were chasing the aluminum wing  "thing".    I found us a qualified aero engineer and we had a 3 hr lunch (on me) While he explained in detail what goes into the design of a SAFE wing.  Oh yeah  this guy was also a DER    (Designated Engineering Representative for the FAA so this wasn't his first rodeo).    I had worked on another project with Dave Thurston (Lake amphib designer and also a DER so I knew what was coming but I wanted Leonard to get it from the horses mouth.      
Spar strength is just scratching the surface in designing a wing.    We could have had one for the princely sum of $5000, from a qualified engineer with nice cad drawings,   either fabric covered or alum skinned  $7000 for both.    Leonard being the frugal soul he is, became short of breath and began wheezing and was feeling lightheaded so I helped him to the car and I drove us back to Sport Flyers.

My suggestion, do it RIGHT or build per plans    this isn't a birdhouse, it will get you high enough off the ground to barely kill you.
LO & SLO  JohnB

PS   the 701 is an 18% thick airfoil  (65018 i think) and DOES take a lot of HP to move it thru the air    plus u gotta figure out how to build it     either with slats,   without, which gives you a bastard airfoil with somewhat unknown qualities or the full version which to my knowledge has never been used on an ultralight.  I have watched the Ultracruiser take off at Osh, followed immediately by a Legal Eagle. Same take off roll, same climb angle. was kinda surprised   thought the Ultracruiser would beat it badly but it's 18% wing might be hard to push also.   Airplanes are a large basket of compromises flying along in formation

[dapug]

My suggestion, do it RIGHT or build per plans    this isn't a birdhouse, it will get you high enough off the ground to barely kill you.

John, what about keeping the profile and wood ribs as designed but swapping in aluminum or carbon fiber spars? 

We know of at least one successful LE XL this way (Bodacious)

[JohnB]

Why go to the trouble  and expense of getting engineering done and just build wood spars instead ??   Attaching wood ribs to alum is gonna be problematic.

[scottiniowa]

John, what about keeping the profile and wood ribs as designed but swapping in aluminum or carbon fiber spars?

We know of at least one successful LE XL this way (Bodacious)

comparisons like this should not be taken lightly-  As how the spars were done on bodacious, are much more than simply being called alum.   If that was the case, you could group all aircraft into about 3 types of wings... which is simply not the case.
Best of success... 
always note, that random generalizations of builds on aircraft are seldom random..