what makes an i beamer an  i beamer? i know this is a dumb question but had to ask because i guess i don't know .
thank you
mark

The spar has the shape of an I-Beam, and the ribs are just "strips" that attach to the LE, spar, and TE.  Usually the riba are 1/8th" wide and 1/4" deep.

so there is relay no ribs just cap strips from the le notched in the spar to the te.
thank you
mark

Hi Mark,

In traditional I-Beam construction, the "caps" of the I-Beam are shaped down to allow the underside of the ribs to glue flush to them.  No "notching" of the ribs.  A sharp corner causes stress risers as you know. 

I have found it somewhat amusing that some think that the slot for the LOs that most I-Beam spars have is cause for alarm.  A few people even go so far as to replace the spar caps with plywood.  This is just a little ridiculous, IMHO.  I do like to face the inside of the TE, and also sandwich between the caps and spar, a piece of .007 strip CF.  The rear support spar is also often left out on the smaller I-Beamers, being replaced with "uprights" to keep the ribs from collapsing. On a plane such as the USA-1 however, that 1/16th' rear support spar is necessary.  Even "X" bracing between the ribs will not lend enough support.

Built as designed, and covered correctly, an I-beam ship is very durable.

Bill <><

When I get home today, (or this weekend) if no one else has posted some pictures, I will take some.  Good ol' *LIFE* gets in the way, sometimes, of what we would REALLY like to do!

Good thing is, work is going great today!  (better not jinx it!)

Bill <><