What is the advantage of an I beam wing?

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Dennis Adamisin:
Advantage to the I-Beam? I'd say look back to the source.

The I-beam structure has its roots back in Detroit and the Strathmoor model club, which met in the basement of the Parks & Recreation building.  The club was primarily Junior & Senior aged kids mentored by a handful of caring adults.  I believe in that atmosphere the classic 50" span I-Beam stunter came about as a result of:

* Easy to scratch build = lower costs versus a kit.
* Built fast - kept kids attention spans focused
* Economical - with almost no wasted wood any kid with a paper route could afford one
* Did not need PERFECT wood - even "medium" wood was usable - and easier to handle too.
* Easy to repair - 1 rib fits all!

Their models performed; the performance of those kids is written into our event's history.

Sadly I think a lot of the OTHER I-beams were lost forever; combat models (I-beams built fast and lent themselves t mass production), and sport models models like Rod Pharis' Berkley profile (Lancer? Interceptor?) which used the I-beam structure.

I only got around to building a couple I-beams in the last few years.  Both are covered in Monocote and both are very stiff and strong - I do not think folks are giving 'cote enough credit for what it can do.  To me, 'cote represented that last piece of the puzzle - a light durable covering for all those ribs!

Bob Kruger:
Quote from: Dennis Adamisin on March 08, 2011, 06:02:18 PM

Advantage to the I-Beam? I'd say look back to the source.


I only got around to building a couple I-beams in the last few years.  Both are covered in Monocote and both are very stiff and strong - I do not think folks are giving 'cote enough credit for what it can do.  To me, 'cote represented that last piece of the puzzle - a light durable covering for all those ribs!



Dennis;

Far be it from me to question your experience, just mine was different, and it could have been my building technique.  Bottom line was my Monocoated I-Beam wings just flexed too much and eventually failed, some sooner than others.  Those covered with silkspan lasted as long as they didn't deaccelerate too quickly from contact with the ground.  And, some of the wings I built were actually fabricated outside of the fuselage using support blocks for the LE and TE so that I could build a straight wing flat on the table with a sheeted center section.  As you mentioned, I-Beam wings were very economical on balsa usage (and I was a kid with a Maine rural paper route of 30-40 customers spread over 6 miles, so every dime counted).  I Monocoated a couple of them when time was short and I had some lawn cutting money in my pocket, and noticed a huge difference in wing flex, especially during high winds.  All failed prematurely.  Those that were silked or silkspanned lasted until I failed and put the plane into the ground.  Bottom line was the doped silk/silkspan took the tension load with less stretch than Monocoat, even though it was not as puncture resistant.  Monocoat was and is tough, but it does stretch a little when under load.  On a true I-Beam, stretch allows flex, and flex induces failure - at least it did in my case (your mileage may vary). 

Perhaps just a different point of reference.

There are few sights with model airplanes that have the understated beauty of an I-Beam wing ship that is graced with near flawless construction and dyed silk or silkspan on a late summer afternoon with the sun shining through the wing as it goes through the pattern.  The overused word "transcendental" comes to mind.   

That being said, I plan on using Ed Ruane's modified Warren Truss I-Beam rib system one of these days.  Perhaps it will reduce flex enough for me that Monocoat will work.

V/r

Bob Kruger

Tom Niebuhr:
Randy,

Ref.  "And after that Paul invented the hard point handle."

Ted was pulling everyone's leg. You took the bait hook, line. and sinker"

Ted Fancher:
Quote from: Tom Niebuhr on March 08, 2011, 09:55:09 PM

Randy,

Ref.  "And after that Paul invented the hard point handle."

Ted was pulling everyone's leg. You took the bait hook, line. and sinker"



 #^ #^ #^ #^ #^ #^

Ted

RandySmith:
Quote from: Tom Niebuhr on March 08, 2011, 09:55:09 PM

Randy,

Ref.  "And after that Paul invented the hard point handle."

Ted was pulling everyone's leg. You took the bait hook, line. and sinker"



hmm  if you say so, none knew that  I guess Ted may have to xplain  the point in that to me some day????

"And after that Paul invented the hard point handle.

Ted"

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