KF IV trailing edge fail

[Ausfox]

I returned from a flight and found that the trailing edge on the starboard side haste failed. It has come from the rivet on the second rib from the fuselage and appears to have been from flexing over the years. Is this a common failure? What is the best way to race/repair this? Thanks in anticipation.

[Dave S]

Rob,

I believe in your profile it says you have a model IV?...Correct?

Not at the rib which holds the flaperon bracket?....correct?

If you have any photos you can post of the failed part and surrounding structure I think it would help list members who have some ideas. Sometimes it is difficult to get a good photo but they sure help if it is possible.

Sincerely,

Dave S

[Jono]

Hi Ausfox,

I'm also keen to see any photos etc, I see you're also in my part of the world :-)

[Ausfox]

Starboard wing, not involved with flaperon hanger. Started at the rivet where the trailing edge is riveted to the rib.


I will get the photos on the site eventually

Thanks

http://www.teamkitfox.com/Forums/picture.php?albumid=397&pictureid=4794

http://www.teamkitfox.com/Forums/picture.php?albumid=397&pictureid=4795

[HighWing]

I had this happen on my first Model IV. My fix was to drill three small diameter holes along the edge at the rib. I then drilled a hole in a stout piece of wood to accept an eye bolt. The wood and eyebolt were positioned between the adjacent ribs with appropriately dimensioned spacers, then safety wire was laced between the eyebolt and the holes on the trailing edge. Tightening the eyebolt pulled out the wrinkles. As the permanent fix, a thick epoxy mix was then injected into an the drilled holes to fill the space between the aft end of the rib and the inner surface of the trailing edge.

This was not an uncommon occurrence apparently as the book was edited.to advise filling the space during wing construction to prevent possible collapse.

[Jono]

hmm... Interesting and a little concerning, Just wondering how many hrs did your air frames have?

[HighWing]

hmm... Interesting and a little concerning, Just wondering how many hrs did your air frames have?

I doubt it is much more than a cosmetic issue. It only happened on one rib in 9 years of flying. All the trailing edge sections were bonded to the ribs with with the structural adhesive supplied with the kits but the bond would occasionally fail - prompting the advice to fill the gap with the adhesive as a backup.

[Jfquebec]

What space do you need to fill Lowell????
I try to figure were..:confused:

[Dutch]

It is now also recomended that the groove in the trailing edge between the ribs be filled in with a stiffener. I used 3/8"alum. tubing some hysol at each end and a few dabs in the middle of each piece. Really strengthend the whole trailing edge. Some have used carbon arrow shafts to save weight.

Dutch

[Ausfox]

Hours A/F 490

[HighWing]

What space do you need to fill Lowell????
I try to figure were..:confused:

The wood end of the ribs don't extenf to the bottom of the V of the trailing edge but align with the surfaces and need to be straight inboard to outboard. The structural adhesive was then used to bond the edge in place. At the flaperon attach brackets the rivets there resisted the collapsing forces of the fabric. But on the other ribs a single rivet was placed which wasn't apparently adequate. The space mentioned refers to that space between the aft end of the cap strips and the inner surface of the trailing edge. Filling that space will prevent the collapse.

I have to apologize as I am in Florida and quite removed from airplanes and manuals and this all from memory. Possibly I missed somethng but essentials are there.

[Ausfox]

It has flown 480 hours.

[Jfquebec]

Thank's Lowell...i understand now:D

[Ausfox]

Thanks for your input folks.

[Jono]

Hi Ausfox,
Sent you a Private Message, just asking where you fly etc... not sure if you got it.

Hope the trailing edge repair is going well.

Jono