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Peter_SE
03-25-2020, 12:10 AM
I’m currently rebuilding my Kf2 wings, replacing spars and I also want to replace my 6 gallon alutanks.

Kitfox sells 13 gallon tanks that they custom make for 650 dollars.

The 13 gal tank involve loosing one rib and change the layout of the stringers.

Is there someone who has 6 gal fiberglass tanks for sale or are there any other options that would be better?

Maybe the 13 gallon option is the best....
https://uploads.tapatalk-cdn.com/20200325/329125d1f37a1e1f790def78ae7390cd.jpg


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avidflyer
03-25-2020, 07:50 PM
Why do you need to replace the spars, if you don't mind my asking? JImChuk

109JB
03-26-2020, 05:53 AM
Why do you need to replace the spars, if you don't mind my asking? JImChuk

https://teamkitfox.com/Forums/threads/10485-Pitotube-routing-hole

I had read that thread and that hole for the pitot tube would not stop me from flying under that spar. The hole is on the neutral axis of the spar where compressive/tensile loads are nil. Without doing a structural analysis, the loads at the neutral axis, which are shear loads are generally pretty low. Think about a built up spar where the vertical spar web is on the neutral axis and what do we generally see there..... Giant lightening holes. I'm not telling you what to do but if it were my airplane I would just make sure the edges of the hole made for the pitot was smooth with no cracks emanating from it and forget about it. Beside that, if Denny Aircraft said to drill a hole then probably most of the early model 1 kitfoxes had that hole and supposedly no Kitfox has ever had an in-flight structural failure. How many hours do the logs say your airplane has?

rogerh12
03-26-2020, 07:16 AM
I rebuilt the wings off a Bede BD-4, that's the big 4-place with 2024 aluminum tube spars, and fiberglass box sections you would slide over the spars to create your wing sections. The design didn't allow for air to circulate around the spar tubes, and as a result there was substantial pitting and white powder found on the spars, after we cut the glass sections off, due to moisture . No alodine or other protection was applied to the spar either. However, the kitfox spare is designed so air can flow around it and dry it back off if it gets moist, so I would expect the spars to last for many decades of regular use.
Roger

Peter_SE
03-26-2020, 08:28 AM
https://teamkitfox.com/Forums/threads/10485-Pitotube-routing-hole

I had read that thread and that hole for the pitot tube would not stop me from flying under that spar. The hole is on the neutral axis of the spar where compressive/tensile loads are nil. Without doing a structural analysis, the loads at the neutral axis, which are shear loads are generally pretty low. Think about a built up spar where the vertical spar web is on the neutral axis and what do we generally see there..... Giant lightening holes. I'm not telling you what to do but if it were my airplane I would just make sure the edges of the hole made for the pitot was smooth with no cracks emanating from it and forget about it. Beside that, if Denny Aircraft said to drill a hole then probably most of the early model 1 kitfoxes had that hole and supposedly no Kitfox has ever had an in-flight structural failure. How many hours do the logs say your airplane has?

Hello!

The problem is that the hole is larger than what is stated in the manual...But I sure it is still ok as you say...problem is that I will be thinking about that damn hole all the time while flying.

I think changing the spar will make me sleep better [emoji3].

Also the Ali tank is drilled and riveted into the spar and maybe it is best to get rid of that when changing wing tank

The airplane has 200 hours on it


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Peter_SE
03-26-2020, 08:29 AM
New 13 gallon fiberglass tanks make good sense because you are replacing the spars anyway.

Yes probably but what to do about the stringers...that attach to the second spar, move to third spar?!


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Peter_SE
03-26-2020, 02:15 PM
This is how i look in my original build manual, maybe just move all of the to the right in between rib 3 and 4

https://uploads.tapatalk-cdn.com/20200326/b57e0544ef59d47ab7dd2fcd56e81957.jpg


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Peter_SE
03-26-2020, 02:16 PM
This is how i look in my original build manual, maybe just move all of the to the right in between rib 3 and 4

https://uploads.tapatalk-cdn.com/20200326/4bd36b0e28c9b0508b63dcf2153c161c.jpg


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KNickman
03-30-2020, 01:18 PM
I’m currently rebuilding my Kf2 wings, replacing spars and I also want to replace my 6 gallon alutanks.

Kitfox sells 13 gallon tanks that they custom make for 650 dollars.

The 13 gal tank involve loosing one rib and change the layout of the stringers.

Is there someone who has 6 gal fiberglass tanks for sale or are there any other options that would be better?

Maybe the 13 gallon option is the best....


https://uploads.tapatalk-cdn.com/20200325/329125d1f37a1e1f790def78ae7390cd.jpg


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Why do you want to replace the aluminum tanks? Would you consider selling them?

Peter_SE
03-31-2020, 08:49 AM
I don’t want any problem with leaking tanks in the future and they have already been repaired once.

I can sell them if you want


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KNickman
03-31-2020, 09:30 AM
After looking into the problems with aluminum tanks I decided to build my own carbon fiber tanks. I will just make the tanks fit between Ribs 1 and 2 as per plans.
Thanks

Peter_SE
04-01-2020, 07:16 AM
Great idea, maybe I need to go that route as well... I mean I have the mold and in my model 2 every kg counts


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