Angle of incidence

s2d · Post by **s2d** » Thu Apr 23, 2009 22:17

Can anyone tell me the true Angle of Incidence of the inboard rib on the champ and chief.

Nathan K. Hammond · Post by **Nathan K. Hammond** » Fri Apr 24, 2009 01:24

1* when measured off the leveled floorboard.

nkh

s2d · Post by **s2d** » Fri Apr 24, 2009 08:47

Thank Nathan.

Is that a measurement using the true chord or the bottom of the wing?

flyingfool · Post by **flyingfool** » Fri Apr 24, 2009 12:11

My floorboard in my chief is in two peices with a slight angle between the two. Which one is used for level?

s2d · Post by **s2d** » Fri Apr 24, 2009 22:32

I wish I knew, I asked that question here a couple years ago and got conflicting answers.
If I knew, I could check out the AOI myself.

Paul Agaliotis · Post by **Paul Agaliotis** » Fri Apr 24, 2009 23:14

The incidence angle would be measured to the chord line of the rib. The wing bottom may not be parallel to the chord line.
Paul

s2d · Post by **s2d** » Sat Apr 25, 2009 06:47

Does anyone know what the angle of the horzontal stabilizer should be with the aircraft level?

Scott Rower · Post by **Scott Rower** » Sat Apr 25, 2009 07:39

Hope this helps.

Also, the chord line on a 4412 airfoil is not the bottom of the airfoil.

Scott

s2d · Post by **s2d** » Sat Apr 25, 2009 15:59

If the tail on the Champ is the same on the Chief, it does.
do you have one of those for the chief, or know where I can look?
I'll try www.aeronca.com when I get to a computer faster than this dialup I'm on at the moment
Thanks

Post by **joea** » Sat Apr 25, 2009 18:19

All of the control surfaces and horiz stab are the same between the 7 & 11 series airplanes EXCEPT for the 11CC, which are the same but counterbalanced.

s2d · Post by **s2d** » Sat Apr 25, 2009 18:24

Is the Horizontal Stabilizer set at the same angle on both? (-3.5*)

David Johnson · Post by **David Johnson** » Sat Apr 25, 2009 19:16

The tail surfaces are the same as Joe says. However, the tail incidence is different. It is in each manual. I am at Sun n Fun and cannot look it up. The Chief has less incidence. I have always believed it is the reason for the speed difference. Chief has less CG change to deal with with different loading. David J.

s2d · Post by **s2d** » Sat Apr 25, 2009 20:54

thanks David thats what I was wondering. I can figure out which floorboard to use as level on my 11CC if I know the angle of incidence on the 11 series horizontal.

s2d · Post by **s2d** » Sat Apr 25, 2009 21:41

Using drawing 4-901A horiz stab and drawing 7-580 fuselage, I come up with the following dimensions and angle

Centerline of tubes front to rear Horz stab 22.5"
Heighth of front tube C/L above reference line 16 1/4"
Heigth of rear tube C/L above reference line 18 3/32"

difference in heighth over 22.5 " is 1.84375 = -4.7 deg
this should be the horiz stab angle of incidence unless some of my dimensions are wrong.

However, two diferent 11 series operating online manuals list the figure as -3.5 deg

s2d · Post by **s2d** » Tue Apr 28, 2009 13:23

Scott Rower wrote:Hope this helps.

Also, the chord line on a 4412 airfoil is not the bottom of the airfoil.

Scott

I find it very interesting that this particular drawing lists the angle of incidence on the horiz stab at -3.5* when the service manual lists the angle of incidence for the tail surface at 5* for the 7AC and 3.5 for the 11AC.

I've posted ssome measurements from my 11CC on the next entry.