2 Magnum center ribs needed

13 posts in this topic

Posted

Hi guys,

I am going to eliminate the wing tip tanks on my wings, but to do this I need 2 more ribs. Any one got anything laying around that may work?

Thanks Barry

 

IMG_9012.JPG

IMG_9013.JPG

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Posted (edited)

Barry,  IMO the tip tanks are terrible to put on one of these birds - The inertia they can cause could really get you into trouble, especially in spin recovery.   You say "Center Ribs" - Is that ribs with or without tails on them, or false ribs?   I think I have some new Raven or Kitfox ribs that I could sell you - They may not be an exact match, but should work - maybe with a little modification on the tail ends, or slight change in rear spar height holes.  I can take a photo for you.  $30 each plus shipping.  I think you could get by with nothing or maybe a couple of false ribs in that space?   I could send you some Kitfox false ribs cheaper.  Someone else might have some Avid spares to sell, and that would be fine with me.   Check with Jim Chuk "1avidflyer".   EDMO

Edited by EDMO

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Posted

Barry,  are you talking actual ribs or just false ribs?  JImChuk

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Posted

I wanted to put a full rib, the one that goes between the spars in. But after studying it more, I think I can just make some more nose rubs and put in and it will be fine. It is 16" between ribs out on the end. As long as it will be strong enough I'm okay with it. Any advise is welcomed. 

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Posted

What is the spacing on the rest of the ribs?  All the lighter weight Avids had ribs on 18" centers.  The Heavy hauler was at 12".  Kitfox uses 18" on all their planes as far as I know, and they go up to 1550 gross weight.  Putting in the false ribs would be lots easier than adding a complete rib and having to take the wing tip off.  Food for thought..... JImChuk

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Posted

The rest of the ribs are 12" on center. The 16" spacing is to fit the tip tank in. I think I will proceed with putting in the false ribs, way simpler. I'm not a structural engineer so I rely on other experienced builders advice ;))

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Posted (edited)

Put the false ribs in, or as an option, put a piece of 1mm plywood, .020" aluminum or fiberglass where the tank went, or same length as false ribs - You are only wanting to maintain the airflow over that area - not worry about structural - there is very little lift on the end of the wing and you have a tip rib there for strength.   EDMO

Edited by EDMO

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Posted

Ed,

Thanks! I think I will do the false rib route. Quick and easy. 

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Posted

You could add a third false rib instead of just two like in the other spaces to keep the fabric from dipping in so much between the ribs once it's tightened.  JImChuk

PS  I thought I had posted this a half hour ago.  I guess I didn't hit the submit reply button.....

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Posted

Jim, that is exactly what I plan on doing. I just got home from a cabinet shop who gave me enough scrap to build the ribs.  Thanks!!

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Posted

Here are my completed ribs. Thanks guys!

94.jpg

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Posted

If you plan on using just the nose ribs in the old tip tank bay, I would suggest adding one more drag tube to that bay. That is what both Avid and Kitfox recommend when omitting a tank. The tanks do add some degree of structural integrity that is best replaced in some way.

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Posted

If you plan on using just the nose ribs in the old tip tank bay, I would suggest adding one more drag tube to that bay. That is what both Avid and Kitfox recommend when omitting a tank. The tanks do add some degree of structural integrity that is best replaced in some way.

Yep, I saw that in the plans, and thanks for reminding me!

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