Aussie Horn STC Instructions in Conflict

[Jim Ivey]

When you assemble the new horn to the torque tube the instructions say to put Loctite 609 on the holes on the back side of the horn (away from balance arm) and insert the bolts from the front to the rear (like Piper did). But the drawing shows just the opposite on the bolts and on the Loctite 609. Huh?

Same thing on the balance arm bolt.

What are y'all doing on the Loctite 609?

Jim

[MULEFLY]

Call Johnston (probably where you got it from) or Tim Talley at Clifton Aero, or Cliff Wilewski at Heritage Aero... each have probably done at least a dozen by now.
Jim

[Don Ostergard]

I use several Loctite products here in my farm shop on automotive/ag/industrial equipment. I cannot find a retaining product "606" in any of the (considerable) Loctite literature in my possession. The "609" works well in a tight slip fit/press fit application. There is also a "660" product that is designed to fill large gaps (i.e. where a bearing housing or a shaft may be worn); this product would be totally unsuitable for this purpose. I think the "606" is likely a misprint. As suggested, I think you should talk to one of the experts mentioned. Better yet, since you have the component out of the plane anyway, why not just sent it to one of them and have the job done by someone who really knows what they are doing? The peace of mind may be worth it.
Don Ostergard ICS 3263

[Jim Ivey]

Mulefly Jim,

Thanks. We have been in contact with Charlie at Johnston. It was after hours when I posted the initial question here and Charlie wasn't at work. He is super.

Don,

I corrected the typo in the first sentence. Loctite 609 it is. The number was right in the other two locations in the balance of the message. My bad on the first. I have all pertinent data and know what Loctite 609 is. The point was there is a direct conflict in it's use callout in the Aussie instructions along with a bolt insertion ambiguity. Somebody missed out proofing before release.

You imply I don't know what I'm doing and need to ship off the assembly. I am a farmer too (and former DER and airframe structural design project engineer). Just finished dragging off cotton. The rest of the reply was basically you further implying you haven't read the Aussie STC instruction sheets and don't know the answer either when it comes to the direct conflicting procedures. Okay then.

Meanwhile we have done two more Aussie horns since the first post. We even have a special rig for disassembling incorrectly bonded Aussie horns from the balance tube in case the insertion process goes awry (yet to happen). It's also great for pulling the original Piper horn.

Jim

[Don Ostergard]

Hello, Jim;
I had hoped to phone you personally this morning to apologize for my clumsy wording but was unable to do so because your personal information in the Pathfinder is private.
I did not mean to imply that you do not know what you are doing, although upon re-reading my post I can readily understand how it could be interpreted that way. Given the clarity of hindsight, I should have suggested sending off the assembly to someone who has gained the experience that comes from having done this job a number of times. This was the message I had hoped (and unfortunately failed) to convey.
I most emphatically did not wish to insult you. Please accept my apology.
Don Ostergard, ICS 3263
c-flhv@magtech.ca
(403) 823-0405

[Jim Ivey]

Don,

I know many times it is hard conveying sentiment in written word. I often come across wrong myself (very often). It's a reflection of the modern texting world we live in. Quick written messages can't express context or light. You can't see the twinkle in somebody's eye or the red of their cheek when writing. I was pretty tired when I replied yesterday. It wasn't my best moment and my reply reflects as much so you deserve an apology too.

No offense taken and I am really glad to have the support of fellow ICS members such as yourself. Things are getting pretty tight in aviation these days and ICS membership has also waned so it's always good to have like-minded support from fellow Comanche brethren.

Since we're blowing some well-deserved sunshine, here's some quick photos of some of the Aussie Horn STC work we've been up to. I would encourage anybody to comment or let us know if they see anything we should fix or redo prior to release.

Cherry Picker used to apply gradual pressure while removing original horn from balance tube. This can also be used to disassemble the Australian horn later if necessary. The shiny cross tube in the horn is NOT the stabilator torque tube. That is an old Bonanza strut shoved through the horn we used for pulling:



Here's another:




Here are some holding blocks we made out of high-density plastic based on Biob Weber's wood block design as seen at the Webco tail seminars:





And some before and after priming shots:





We will follow with a quality Jetglo finish paint.

Important items I don't have pictures of yet:

Oven.
Dry ice chest.
Telescoping bore gauges and micrometers.
Loctite and reamer tool kit.

This STC is not for the casual do it yourselfer unless they are comfortable with precision measuring and handling oven-heated Aussie horn as it is assembled to a below-zero frozen balance arm all the while contending with heat-activated structural adhesive (we are batting 100 thanks to Charlie at Johnston). Care with the parts at every step is mandatory.

Jim

[Kristin Winter]

I second the notion that one shouldn't wade into this unless you have precision micrometers, T-gauges, and know how to use same. I lot of A&P's do not meet this criteria.

I have removed the balance arm by supporting it upside down on a rod almost as large as the diameter of the torque tube and then with a short chunk of cast iron pipe that slipped over the balance arm and tapped against a bolt through the hole at the end of the balance arm. It takes pretty mild taps to get it to come out once the horn is warmed up to 230-250F.

[Richard L Doehring]

These were very useful post. Must admitt that I missed the conflict between the drawing and instructions in item 76 of the assembly instructions when first reading it. I am curious if anyone has knowledge, rather than conjecture, as to why the fit of the balance arm to the horn is so close and critical? The fit obviously presents some problems and I would think I would want to have the maximum allowable clearance to ease the assembly. I haven't done this yet but am getting ready to jump on it shortly. My pride has been injured because Mr. Ivy, rather than myself, thought of the engine hoist as a puller. Neat Idea. I was already fabricating a slide tube like Ms. Winter described, still may go that route anyway.

The assembly instructions, item 24, I believe is simply instructing the installer to measure the bore and record it on the form in Item 25. The wording of 24 is a little quirky and says "identify the bore diameter of the new Stabilator Horn which is written on the release sheet for and write this......" It seems to implies that there is some separate release sheet that contains the measurement, I believe this to be incorrect but then again I don't speak Aussie.
Lastly, I am concerned that I may not like what I see in my torque tube when I get it completely exposed. Just in case, who has them in stock and for about how much if anyone knows.

Thanks to all for the good narrative regarding this subject.

Richard Doehring