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Building Tips and technical articles. => Building techniques => Topic started by: mark eisenhut on January 18, 2007, 05:45:10 AM

Title: i beam construction
Post by: mark eisenhut on January 18, 2007, 05:45:10 AM

 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

Title: Re: i beam construction
Post by: Bill Little on January 18, 2007, 06:27:30 AM

Quote from: mark eisenhut on January 18, 2007, 05:45:10 AM

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.

Title: Re: i beam construction
Post by: mark eisenhut on January 18, 2007, 06:51:37 AM

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

Title: Re: i beam construction
Post by: Bill Little on January 18, 2007, 07:21:34 AM

Quote from: mark eisenhut on January 18, 2007, 06:51:37 AM

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.  ;D

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 <><

Title: Re: i beam construction
Post by: mark eisenhut on January 19, 2007, 07:35:49 AM

thanks bill
would you have any  pictures i think i understand  just cant picture it in my head
thanks again
mark

Title: Re: i beam construction
Post by: Bill Little on January 19, 2007, 07:44:22 AM

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! :D

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

Bill <><