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[Daniele]

Hello to all,
Daniele from Italy I am writing ,
I wanted to ask a technical information for a ' plane Kitfox 3 .
I have attached a picture with the white lines to make you better understand what I want to ask .
I have to buy a Kitfox in Italy , before you buy , and I had a doubt on that part that I showed you , of course I took that picture on the site is not original .
wing of the Kitfox uprights have the final with the thread with ball terminal.
Now I want to ask? but it sure that the posts on the thread of the work mounted ?
seeing other aircraft have the pin who works on the beam . can you give me some information about safety ?
because from my opinion not good download force on the thread of the post , the ultimate in theory should end up with a cross pin .
then why you should set ? It should be fixed .kit fox.jpg

[Dave S]

Daniele,

I am not 100% sure I understand all of your question; but, let me try.

If I understand your question correctly (please correct me if I do not) you are concerned about the forces which you believe may act crosswise on the thread of the rod end.

1) This is the design Kitfox aircraft have always had on the attachment point between the spar and the lift strut. I think more recent models may use a male rode end which screws into the end of the lift strut while the model you are considering has a female rod end which recieves a threaded rod from the end of the lift strut - this is just two different ways of doing the same thing.

2) The wing of a kitfox has a certain amount of flex to it - you can observe the wing tip flexing up and down a small amount when flying. The purpose of the rod end ball is to prevent any perpendicular force from being applied to the threaded part because of the wing flexing. Freedom of movement of the rod end ball and lubrication to the rod end ball is a point we keep in mind at annual condition inspection time. As long as the ball can swivel (and it is an extremely small amount) there will be no perpendicular bending force on the threaded part. All of the force, both tension as when flying and compression when on the ground or doing negative Gs will be straight down the center line of the lift strut and the center of the threaded portion of the rod end. Part of your instruction manual also explains that the front and rear lift strut tubes that go between the bottom of the fuselage and rod ends on the wing spar bracket must be straight with no bowing when the jury strut is attached The geometry of the system guarantees a safe and durable assembly provided that it is assembled according to plan and that the rod end can freely rotate for the very small amount of movememt it is designed to accomodate.

3) As a note to provide you some assurances. One of the features of the Kitfox is the strength and durability of the airframe and wing. There are many Kitfoxes flying and have been flying for approximately 3 decades. While a few people have had the customary and usual occasional pilot error incidents or problems with a powerplant, I don't think there has ever been a case of a kitfox having a structural failure.

Please speak up if I miss read your question.

Good to have you on board in this community.

Sincerely,

Dave S
Kitfox 7 Trigear
912ULS Warp Drive
St Paul, MN

[Dutch]

Hello Daniele
If your question is about the bolt going through the ball joint? Then the answer is,The shank of the bolt in contact with both the ball joint and the spar
attachment should not be threaded. If on the other hand you are concerned about the threaded rod end on the ball joint? That is a common component on most aircraft

Dutch