Author Topic: Fuselage Top Longeron Gusset Tubes - Necessary or Not?  (Read 440 times)

jonfilipa

  • Subscriber
  • registered
  • *
  • Join Date: Jun 2009
  • Posts: 11
  • My Gallery
  • Engine: 2276
  • Sonerai Model: II-LS
So I'm working on welding on the various odds and ends for my IILS fuselage and am looking for feedback on the whether the tubes labeled A, B, and C in the attached pic are necessary or not.  A couple reasons for asking:
1) I know the "C" tubes have to be left out as it makes getting in and out the plane much easier given my 6 ft 2 in height and 34 in inseam.  (Fred - thanks again for letting me "try on" your airplane at Airventure  8))
2) I'll take whatever weight savings I can get.

That being said, beyond providing some level of gusseting (not necessary in my opinion given load path) do these tubes provide any level of functionality beyond being a hand hold for getting in and out of the airplane?  Just checking to see to make sure I'm not missing something. 

Raceair

  • Subscriber
  • registered
  • *
  • Join Date: Oct 2007
  • Posts: 1064
  • My Gallery
  • Engine: 1600 c.c.
  • Sonerai Model: Sonerai one
The tubes are there for two reasons.    Reason one,   in a crash,   they tend to send a broken longeron out and away from the occupant, rather than poking into the occupant.   Reason two,    these bays torsionally are inferior without some type of triangulation, and would tend to trapezoid under load without the diagonals.....    The bonus is that they do help as a handhold in getting in....

jonfilipa

  • Subscriber
  • registered
  • *
  • Join Date: Jun 2009
  • Posts: 11
  • My Gallery
  • Engine: 2276
  • Sonerai Model: II-LS
Reason 1 is more than sufficient for me.  Thanks for the feedback Ed!

Pttim

  • Administrator
  • registered
  • *
  • Join Date: Mar 2008
  • Posts: 1515
  • My Gallery
  • I thought this would only take a year!
  • Engine: Great Plains 2180
  • Sonerai Model: SIIL
Looked at mine last night, they are there in the aft compartment but not the front.
Pttim
____________________________________________________

Member:  Tail Dragging Stick Monkey Association

Thaddeus

  • Subscriber
  • registered
  • *
  • Join Date: Jul 2014
  • Posts: 143
  • My Gallery
  • Engine: Corvair 2700
  • Sonerai Model: 2LT Minus-1 Gonnabe
I'm going to modify this same section on the corvairai.  It's just too dang tight getting in and out and I'm planning on wearing a chute.  The idea of floating down with the bird hanging on my legs just won't do.  Since it will be a 1.5, not a II, I do not care about sacrificing the front seat area.  (Wife has given me a thumbs down vote of confidence).  Instead, there will be more bracing, an aux fuel tank, and the panel will be moved back to the modified cross member.  The cross member will be triangulated, doubled, and gusseted, so it should take any loads.  Here is the plan.
"It seems wisest to assume the worst from the beginning...and let anything better come as a surprise.” 
― Jules Verne, The Mysterious Island

 

Recent Topics

AeroVee Aeroinjector woes! by Smokyray
Oct 21, 2017

LTS Gear Longeron Damage by Thaddeus
Oct 21, 2017

Cowling problems by mtdanet
Oct 18, 2017

Brown and Sharp # 5 reamer by Chucker
Oct 18, 2017

Secondary spark plug holes by Mytonic
Oct 18, 2017

Diehl engine casing by Chucker
Oct 17, 2017

Any Central Texas Sonerai II's - Need a Fit Check by dbonorden
Oct 16, 2017

685L lands away from home base for the first time. by mhflyit
Oct 15, 2017

As easy on the ground as in the air! by mhflyit
Oct 15, 2017

Trailering Wing Cradle by jamdfingr
Oct 15, 2017

Elevator Control System Stiffness by flyboy9000
Oct 15, 2017

Viking 130 in a Sonerai? by dcstrng
Oct 15, 2017

Aeromomentum Engines by eschrom
Oct 14, 2017

Stall speed real world data by GmoneyMacFresh
Oct 12, 2017

Powered by EzPortal