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Seat Reinforcement

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kitfoxjim

Joined: 30 May 2007
Posts: 7
Location: SC

Posted: Sun Sep 02, 2007 4:48 pm Post subject: Seat Reinforcement

Wow! Had a close one yesterday. Has anyone had a seat failure? I have a Vixen and was doing touch and goes in windy conditions for practice. Had a fairly hard but not esp hard landing. When I lifted off again, I noticed the controls were locked.



I then noticed the seat had broke loose and was against control tubes. Managed to get it down by holding my weight off the seat by grabbing the tubing overhead long enough to get down. but was very scary 



Any suggestions on reinforcing the seat so this wont happen again?



Thanks

kitfoxjim

Kitfox Vixen

Fox5flyer
Guest

Posted: Sun Sep 02, 2007 5:15 pm Post subject: Seat Reinforcement

It's good that you're okay, Jim.

We had a member on this list who, several years ago, had the exact same

thing happen to him on landing.  The nylon cable ties broke loose on a hard

landing, the seat dropped down on the main elevator control rod, locking it.

He lost control and wrecked the airplane pretty bad.  I believe it was a

series 5 and I think he had a passenger.

That prompted many of us to add additional support straps to hold the seat

in place.  Some used stainless steel straps.  I used seat belt 2" wide

straps.  Others placed blocks of wood under the seat so that it couldn't

drop down.  There were other fixes, but I don't recall what they were.

Perhaps other members can add something.

It's good that your quick and clear thinking was able to save both the

airplane and probably your life.  This is obviously something others should

have a good look at.

Deke



---

CDE2fly(at)aol.com
Guest

Posted: Sun Sep 02, 2007 6:16 pm Post subject: Seat Reinforcement

Jim:

  

 I'm nearing the completion of a Kitfox 7 and have looked at this issue  fearing the same possibility.  My solution was to fabricate a couple of  slings that go under each side of the seat (total of 4 in all) andwrap around  the structural tubeing that suports the seat.

  

 The slings are fabricated from steel strapping normally used for pipe  hanger material that can by purchased at most hardware/home improvement  stores in the plumbing department.  The strapping comes with pre-formed  holes so once you have the correct length so that the fiberglass seatpan rests  on the slings, secure with AN hardware.  After installing the  slings, the seats are very solid and will withstand much more load than the  stock setup.

  

 Chris 



Get a sneak peek of the all-new AOL.com.

  [quote][b]

jezim(at)pro-ns.net
Guest

Posted: Sun Sep 02, 2007 8:22 pm Post subject: Seat Reinforcement

I used nylon lifting straps.

 Jim  Series 5  0-200  building.

 Lake Elmo MN.

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Fox5flyer
Guest

Posted: Mon Sep 03, 2007 2:39 am Post subject: Seat Reinforcement

Chris, that is very similar in principal to what I and many others have  done.  However, I used seat belt material.

  

 Deke Morisse

Mikado Michigan

S5/Subaru/CAP 355+ TT

"If you don't  read the newspaper you are

uninformed, if you do read 

the newspaper you  are misinformed."

Mark Twain

  

  

 [quote]   



   Jim:

    

   I'm nearing the completion of a Kitfox 7 and have looked at this issue    fearing the same possibility.  My solution was to fabricate a couple of    slings that go under each side of the seat (total of 4 in all) andwrap around    the structural tubeing that suports the seat.

    

   The slings are fabricated from steel strapping normally used for pipe    hanger material that can by purchased at most hardware/home improvement    stores in the plumbing department.  The strapping comes with pre-formed    holes so once you have the correct length so that the fiberglass seatpan rests    on the slings, secure with AN hardware.  After installing the    slings, the seats are very solid and will withstand much more load than    the stock setup.

    

   Chris 



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 	  Quote: 	
		  



href="http://www.matronics.com/Navigator?Kitfox-List">http://www.matronhref="http://forums.matronics.com">http://forums.matronics.com



	
[b]

Fox5flyer
Guest

Posted: Mon Sep 03, 2007 2:43 am Post subject: Seat Reinforcement

Very nice Jim.  What are those attachments on  the straps that you used?

  

 Deke Morisse

Mikado Michigan

S5/Subaru/CAP  355+ TT



 Subject: Seat Reinforcement

 [quote]   



   I used nylon lifting straps.

   Jim  Series 5  0-200  building.

   Lake Elmo MN.

[b]

jezim(at)pro-ns.net
Guest

Posted: Mon Sep 03, 2007 7:09 am Post subject: Seat Reinforcement

3/16 pop rivets with 5/8 heads. Covered with heavy duty shrink wrap.

 [quote]   ---

clemwehner(at)sbcglobal.n
Guest

Posted: Mon Sep 03, 2007 4:23 pm Post subject: Seat Reinforcement

I've  thought about using two blocks of balsa wood, one on each side of the elevator  pushrod. Any thoughts on this approach? 

  

 Clem  Wehner

 Lawton, OK

 Mod  IV-912

  

 [quote]   

   -----

[b]

Mdkitfox(at)aol.com
Guest

Posted: Mon Sep 03, 2007 7:07 pm Post subject: Seat Reinforcement

Clem,

  

 Just my 2 cents, but why Balsa?  It may be light, but wouldn't provide  much strength or support due to the span, if the seat load falls on it.   Spruce, at a little more weight, is much stronger and could possibly  support the load.  However, the real problem with both (especially the  spruce) is, there is no crush zone.  So after the small seat cushion  and tush, your spine gets to absorb the g -load.  Ouch!  It seems  the web material or seat belt material has some give and then retains the seat  pan over the controls.

  

 I went with the webbing, but either way, I think doing something to keep  the controls from getting jammed is necessary.

  

 Rick  Weiss

Series V Speedster - N39RW, 912S Power



DO NOT  ARCHIVE



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  [quote][b]

occom

Joined: 26 Aug 2006
Posts: 404

Posted: Tue Sep 04, 2007 2:29 am Post subject: Seat Reinforcement

I found this in the Kitfoxsafe list aI saved some time ago. It appears to  apply here. 

  

  

 #34

CONCERN:  (MINOR)(PRIMARILY SERIES V) FIBERGLASS SEAT BREAKING  RESULTING

          IN JAMMED  CONTROL LINKAGE

DATE:     6-29-99

IMPACT:    Breaking of the seat or seat coming loose from the fuselage  

          support tubes could  result in the below control tubes  becoming

          Jammed.   A complete loss of control of the aircraft  could

           occur.

"LIST":   1.  Ensure the seat is properly and securely  attached to  the

               fuselage tubing

           2.  Look at reinforcing the fiberglass seat in the areas  where

               it attaches to the  tubes

          3.  Provide  full length support from top to bottom (seat  lips)

               with either stainless strap or webbing of some  sort.

          4.   Consider using metal hose clamps vice plastic tie wraps  to

               secure the seat.

           5.  Inspect the seat frequently for signs of cracking.  

               Especially after any hard landings.



  

 Dave Goddard- Mod IV 1050/582

do not archive

   [quote][b]

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