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motortommy
09-01-2019, 12:18 PM
while rebuilding my IV, I want to save some weight.
Could someone provide me the tube dimensions of the lift struts? I know it‘s 1“ outer, but what about wall thickness? With some numbers I could calculate the standard weight w/o fairings...

My struts are very nicely done and looking. Fairings are made of foam wrapped with fiberglass, filler and finally painted. I fear that this makes the struts very heavy...

Each of my strut including jury and unibal (ready to bolt on) weights 13,9lbs (6,3kg). Should I strip them down and use e.g. factory pvc fairings? Would be great, if anyone could support me with some numbers...

Thanks,
Marc

avidflyer
09-01-2019, 07:00 PM
My Kitfox 4 kit came with high density foam that was to be glued onto the struts, shaped, and then covered. Probably the lightest way to go. JImChuk

HighWing
09-01-2019, 08:58 PM
Agree with Jim. I have a piece of the PVC fairing and after weighing, measuring and some calculations, the factory fairings will add 14 lbs to the lift struts on top of the lift struts themselves or about 7 lbs per side - and this is without any of the closures at the V. Weigh one of your struts and subtract the 7 lbs and it should give you a pretty close estimate of the strut weights. on my IV, I used aluminum filled with urethane foam. The aluminum weighed about 2-3/4 lbs per side and they were then filled with liquid expanding urethane foam for another half pound per side. As Jim suggested, you will probably not save any weight and expend a lot of energy making the mods you are suggesting.

motortommy
09-02-2019, 01:03 AM
Thanks!
Ok mine are 13.9 per side. PVC fairing subtracted means 6.9 lbs of steel.
16.5ft of strut material should be about 8lbs (e.g. 4130 1”x .049) plus jury struts, AN hardware and welded bracket, maybe another 2.5lbs.
Conclusion: my fairings are about 3.5lbs per side and therefore even on the light side. I don`t think I can make it any lighter while keeping appearance…or did I missed something?

23044

rcbif
09-02-2019, 05:22 AM
I have the aftermarket streamline lift struts from Kitfox and the factory lift struts with no fairings on them.

They are both wrapped and tied together in pairs now for storage, but the streamline lift struts do seem around 10-14lb heavier, but from what I hear here, it seems they would be near equal when the factory tube version has fairings added.

I will have to see if my hangar-mate has a scale.