Re: Aeronca 11AC Chief Project FS

On Tue, 24 Jun 2008 14:16:34 -0700 (PDT), Victor Bravo
<dirdev@[EMAIL PROTECTED]
> wrote:

>On Jun 24, 6:32 am, Gig 601Xl Builder <wrgiac...@[EMAIL PROTECTED]
>
>wrote:
>
>> Jay, he's full of crap. The Horz Stab has four attach points. It
doesn't
>> move at all unless you count the fact that the entire airplane moves
>> when you move it.
>
>I am indeed full of crap sometimes, but not this time. The four attach
>points that Dr. Einstein here was referring to are the exact parts
>that moved slightly when I pulled on the stabilizer tip.
>
>Here's a graphic visual example for the mechanically challenged:
>
>Imagine that the four stabilizer mounting tabs on top of the fuselage
>were all 12 inches tall, instead of the one or two inches tall that
>they actually are... So the horizontal tail would be mounted a foot
>above the top of the fuselage.
>
>Under this example, when you tried to move one stabilizer tip forward
>and the other one aft, it would move easily, and the four foot-long
>imaginary mounting tabs would all move back and forth a little as you
>twist the tail left and right (looking from above).
>
>In order to prevent this type of movement, you would have to rivet
>sheets of aluminum between these tall stabilizer sup****ts to make the
>system "torsionally stable". You would be riveting "shear webs"
>between the stab sup****ts, to oppose the shearing (and then twisting)
>relative motion.
>
>Now of course the mounting tabs are not a foot tall, so you cannot
>swing the stabilizer tip fore and aft with one finger like you could
>if it was a foot tall. But the stabilizer mounting tabs ARE an inch or
>two above the fuselage, and this distance is NOT braced in shear or
>twisting. So you CAN move it fore and aft a little, and when you do
>this you CAN see the mounting tabs move relative to each other a
>little.
>
>Ladies and Gentlemen, you CANNOT move the stabilizer back and forth
>this way on an undamaged Cessna, Taylorcraft, Champ, or Beech. You
>cannot do it on a Luscombe, you cannot do it on an undamaged Piper
>Cherokee, and you cannot do it on a Maule and you cannot do it on a
>Grumman Yankee. I can go on if I have not made the point clearly
>enough.
>
>The stabilizer mounting system on the 601 and possibly the 701 is in
>my opinion not rigid enough. The tabs are not braced against shearing
>or twisting. There is no reason you should be able to move the
>stabilizer back and forth on a standard configuration light aircraft
>like that. When you move it like this, you are slightly bending the
>stabilizer mounting tabs (and the attach structure on the fuselage)
>back and forth a little bit each time.


Build a 2000 lb 601.
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