Control Horns

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jeffreyK
Posts: 2
Joined: Wed Jan 15, 2020 9:41 pm

Control Horns

Post by jeffreyK »

I have completed the wood work on the empennage and have started on the metal fittings while waiting for the wing kit. I notice the full size template for the control horns in the plans are asymmetric. The rudder horn is 1/8" longer on one side and the elevator horn is 1/16" longer. Is this intended because of aerodynamics or should they be symmetric? If it is intended which side of the rudder and elevator get the longer side?
I also notice the 8 outboard stabilizer brackets are listed as 12 gauge while all of the other empennage brackets are 13 gauge. I would have thought the two brackets on the rudder would be a heavier gauge since they each take the load of two cables.
I am a retired Neurosurgeon and usually a type A stickler for detail. Any information on this would be appreciated.
TIA,
Jeffrey Kornblum

tom kreiner
Posts: 38
Joined: Sat Feb 25, 2017 9:49 am

Re: Control Horns

Post by tom kreiner »

On page two of the 1933 plans, it appears that the numbers are rather fuzzy in appearance.

That said, I believe that both the stab brackets and the rudder brackets are 13 ga.

Earl Brown
Posts: 11
Joined: Mon Nov 04, 2019 12:24 pm

Re: Control Horns

Post by Earl Brown »

Jeffery

The control horns should be symmetrical. The plans are not always drawn accurately as far as using drawings for templates.
I scanned the plans and then re-drew the horns using the overall dimensions, but making sure they were symmetrical from side to side.

The plans do say that the Upper Wire Fittings are 13 Ga. and the Center Wire Fittings are 12 Ga.
I made all of my tail fittings from 13 Ga.

danoliver
Posts: 36
Joined: Sat Feb 25, 2017 7:58 am
Location: Cincinnati

Re: Control Horns

Post by danoliver »

I made my horns symmetrical (not yet flying). I figured the error was just because the plan's templates were hand drawn. I re-drew the horns on manila folders and cut them out for patterns. Worked pretty good.
As far as the brace fittings I used .090 for the fin and .100 for the h-stab.

jeffreyK
Posts: 2
Joined: Wed Jan 15, 2020 9:41 pm

Re: Control Horns

Post by jeffreyK »

Thank you all for the input. I am moving forward.
JeffreyK

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taildrags
Posts: 301
Joined: Tue Mar 07, 2017 10:39 pm

Re: Control Horns

Post by taildrags »

See, this is where my usual mental logic has broken down. It sounds like the desire to keep the tail light pushes towards making all the fittings out of the 13 ga material. I look at the tail brace anchor straps and see a difference in the metal gauges with no explanation given, and I tend to make all of them out of the slightly *heavier* gauge metal... 12 ga. There could be endless discussion about why Mr. Pietenpol may have used different gauges for the brackets and there isn't any need to try to analyze that.

Oscar Zuniga
Medford, OR

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taildrags
Posts: 301
Joined: Tue Mar 07, 2017 10:39 pm

Re: Control Horns

Post by taildrags »

Oh yeah, and I forgot to say why I was thinking that way. The vertical stabilizer brace wire brackets each take the load of two wires, while the horizontal stabilizer brace wires only take the load of one apiece.

-Oscar

Earl Brown
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Joined: Mon Nov 04, 2019 12:24 pm

Re: Control Horns

Post by Earl Brown »

Guess I should also mention that I separated the wires at the fin, moving one to the leading edge.
IMG_1142.jpg

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taildrags
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Joined: Tue Mar 07, 2017 10:39 pm

Re: Control Horns

Post by taildrags »

Ah. Now I see. Earl, you may want to tweak the angle of the leading edge of your vertical stabilizer after you test-fly the aircraft. Mine is cranked over a little bit to help reduce some of the yaw that I was experiencing even after adding a rudder trim tab and shifting the nose of the engine over a bit by shimming at the engine mounts. If you do that, those two cables will need to be re-made if there are no turnbuckles or other length adjustments available. Not a big deal.

Oscar Zuniga
Medford, OR

Earl Brown
Posts: 11
Joined: Mon Nov 04, 2019 12:24 pm

Re: Control Horns

Post by Earl Brown »

Thanks, Oscar
My fin is already offset- opposite of your of course!

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