[f-AA] wing tip bows

[John Rodkey]

Duane rightly pointed out we've been quiet on the list. So I'll bring up a subject that could perhaps bring out the quieter, knowledgeable types...

My wings were recovered in 1998. Polyfiber/polytone. Over the years, the covering has gradually shrunk so that the aft wing tip bow impinges on the trailing edge of the aileron on hot days. It's not enough to prevent aileron deflection, but there's a slight 'bump' when the two parts meet.  

I need to remedy this issue. If there are any remedies that don't involve removing the fabric, that would be ideal, but I'm not optimistic of that.

Assuming fabric needs to be cut, my first instinct would be to use solvents to release the bias tape around the edge of the wing bow, then the fabric around the edge of the bow, do whatever bending & stiffening that need to be done, then re-attach the fabric and put on new bias tape.

The other option is to remove the fabric from outside the last rib to the end, then recover the whole tip. 

Thoughts?

--

John (poobah) Rodkey - N9361E 11AC at Goleta

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['Ken McClelland' via aeronca]

Pretty sure you are out of luck on any non-invasive fix. The most common thing I have seen is a wood doubler on the rib where it creates the tip aileron bay. This keeps the aluminum rib from deflecting toward the aileron. I’m sure there are drawings for that mod and a less common (to me anyway) corner brace arrangement. But the point is I have never seen it resolved without some fabric work being done.

Ken

Sent from my iPhone

On Apr 2, 2025, at 10:11 PM, John Rodkey <pooba...@gmail.com> wrote:



['Botijo G' via aeronca]

You would had to cut back to the first rib, fix and make stronger the area and recover the tip.

By making it to the first rib you can hide the new seam. Waldo at poly fiber is a great resource. In my wings the original spars were pushed open by the bow so in the new spars I used carbon fiber to reinforce the tip. I also left a bit more of fabric and very carefully heated it up no to crush that last rib. Hey what ever happened with your cylinders?

Rafael 

Sent from an NDB

On Apr 2, 2025, at 7:59 PM, 'Ken McClelland' via aeronca <aer...@westmont.edu> wrote:

Pretty sure you are out of luck on any non-invasive fix. The most common thing I have seen is a wood doubler on the rib where it creates the tip aileron bay. This keeps the aluminum rib from deflecting toward the aileron. I’m sure there are drawings for that mod and a less common (to me anyway) corner brace arrangement. But the point is I have never seen it resolved without some fabric work being done.

[John Rodkey]

I remember that when I rebuilt the wing that there was a triangle of plywood that went in the back of the outer rib, but I suspect that it either was too thin or it has warped over time. I wonder if I have a picture of it during the rebuild, or from one of my annual inspections... Hm. I'll have to look for that.

I was pretty sure that non-invasive wasn't going to work. Nowhere to get any leverage without bending or breaking things.

Yes, you have to not attach the unshrunk fabric tight or it will just do the same thing. Maybe pre-shrink with a lower heat setting before attaching the fabric? Is there a procedure for that?

Regarding the cylinders: I ended up taking all 4 cylinders off, bringing them to Bakersfield (Shafter, actually), and working on them with my mechanic. We reseated all the valves, inspected everything, and reassembled. Drove the lot back home to the hangar, and spent a weekend reassembling the cylinders. Next weekend the mechanic came and inspected, installed and timed the refurbished magnetos, and I've been flying it since. I think I've got 6 hours on it, and it seems to be working well. I should probably do a compression test now that it's had some time to work those rings back in. None of the cylinders feel particularly 'soft', and I don't notice any sounds from any of the orifices, but I should do a more careful check.

It's nice to be flying again.

 

[Don Harvie]

This is what Dad did for his Chief. There are some photo's I took just prior to covering that might help illustrate this. The photo's are in my ancient BG,  (Before Google) Photo album here:

https://www.austerj4.com/gallery2/main.php/v/Don/Flying/Aeronca_VH-IDH/leftwing_cover/?g2_page=1

Specifically these two:
https://www.austerj4.com/gallery2/main.php/v/Don/Flying/Aeronca_VH-IDH/leftwing_cover/IMG_4886.JPG.html
and

https://www.austerj4.com/gallery2/main.php/v/Don/Flying/Aeronca_VH-IDH/leftwing_cover/IMG_4903.JPG.html

I've still got Dad's Chief & am working towards getting time and space to work on it. I've had to cram everything from his home into the hangar to keep it, which has left me a little short on working space - There is the Dad's Stinson fuselage + three wings, His Chief, His Auster project, about half of his home workshop tools, My Auster and RV-6 in a 50'x60' shed. There is a plan to address the space problem.

Don H

[John Rodkey]

Perfect, Don. I definitely had the plywood piece, but I don't recall the diagonal tube, which would make a huge difference. 

['Ken McClelland' via aeronca]

That second picture shows both of the items I have seen combined. The wood and that brace running to the tip of the wood.

Ken

Sent from my iPhone

On Apr 3, 2025, at 12:13 AM, Don Harvie <donh...@gmail.com> wrote:



[Don Harvie]

I have a feeling the diagonal tube might have been a belt & braces fix from Dad.

Don H

On 3 Apr 2025, at 3:19 pm, John Rodkey <pooba...@gmail.com> wrote:



[Richard Murray]

Don (and John)

The diagonal tube was a service letter fix if my memory is correct.

Richard in OH who suffers from CRS on occasion more frequently than he likes.

['Botijo G' via aeronca]

John.

I see no point in the pre shrinking and would be difficult in such a large piece.  The problem I found is that a regular iron does cycle on and off and depending how crazy it is those cycles will go above the preset temperature and way low after that.  I bought this iron that it’s made specifically for fabric covering and you can’t any temp with precision and it does not cycle on and off trying to keep a temp.  I made that area a bit softer than the rest and controlled the shrinking in that area after I did the bigger areas around it first.

I had a trusty wood frame made from scraps and did some testing making pre measured lines to see how much it shrinks.  Also don’t forget that as thin that is the opposite side will heat up while you do one side.

These airplanes were made for cotton fabric that shrinks a lot less than the new fibers so some reinforcement and extra care is needed with modern stuff.  You can’t any temp actually twist a wing is not care full.

Rafael

(That in a single aeronca has covered 3 wings, 8 gear legs and 3 full sets of tail feathers)

Sent from an NDB

On Apr 3, 2025, at 1:33 AM, Richard Murray <murra...@gmail.com> wrote:



[Dan Vandermeer]

If you are coming to SnF, please stop by the museum. I’ll be wearing an Aeronca and a safety vest (to protect me from the rampaging kids.)

Or or better- CHECK IN AT THE AERONCA TABLE IN THE TYPE CLUB TENT IN THE VINTAGE AIRCRAFT AREA!

On Apr 3, 2025, at 00:13, Don Harvie <donh...@gmail.com> wrote:



[Richard Murray]

[John Rodkey]

Bingo! And an early one at that: http://aeronca.celinaux.com/SL/SL-3.pdf

[John Rodkey]

Where can one find this part? 2-10001 L/R (need quantity 2) . Perhaps I'll need to fabricate it.

[Don Harvie]

Thanks John,

You’ve started my Aeronca education.

Don H

On 4 Apr 2025, at 5:09 am, John Rodkey <pooba...@gmail.com> wrote:



[Mark Peterson]

The 3/8" pine or spruce piece is Aeronca 2-699 and the diagonal tube is not a bad idea but I can't find it in service bulletins or Aeronca's helps and hints.   You should also use the butt rib in that location to add a little stiffening.

Mark

---

From: aer...@westmont.edu <aer...@westmont.edu> on behalf of John Rodkey <pooba...@gmail.com>
Sent: Wednesday, April 2, 2025 9:18 PM
To: aer...@westmont.edu <aer...@westmont.edu>
Subject: Re: [f-AA] wing tip bows

 

['Paul M. Antom' via aeronca]

Here’s the wingtip info.

 

.

['Botijo G' via aeronca]

Interesting they removed that part and then re added it because the prewars have it

Sent from an NDB

On Apr 3, 2025, at 4:33 PM, 'Paul M. Antom' via aeronca <aer...@westmont.edu> wrote:



<Wingtip brace.pdf>

[Mark Peterson]

No wonder!   It’s a Champion repair, not an Aeronca one.  

Sent from my iPhone 

On Apr 3, 2025, at 4:33 PM, 'Paul M. Antom' via aeronca <aer...@westmont.edu> wrote:



Here’s the wingtip info.

 

.

<Wingtip brace.pdf>

[Mark Peterson]

Also interesting:  they included the 11 series, even through they weren’t being produced by themselves.  Good!  And they have you drill into the spar, which nowadays makes one nervous.  With the small loads on the wing tip it’s good, but with the spar AD we are more nervous about it! 

Sent from my iPhone 

On Apr 3, 2025, at 4:33 PM, 'Paul M. Antom' via aeronca <aer...@westmont.edu> wrote:



Here’s the wingtip info.

 

.

<Wingtip brace.pdf>

[alan miller]

Nice to see the Rodkey list lighting up again!

 If any Aeronca folks wander through the warbird ramp swing by the B25 Betty’s Dream and say hi.  It is the green one. I am the tall goofy ugly guy in the brown Aussie hat.  We will be leaving in it tomorrow after the show.  If I get a chance I will swing by the type club tent and say hi.

Aloha,

alan 

[Richard Murray]

Alan I am sorry I got this too late. I bailed about 1;30 today and just read your post. Dion Carr and David Johnson should be at the Type Clubs Tent after 10;30. Sometimes they get there by 9:30.

Richard in OH setting at Buc-ee's in Calhoun GA reading his messages.