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WING STRUTS

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Posted

I have to modify my wing struts to make them heavier and longer: I think I have seen later model struts without the connecting tube at the wing end - Am I right on this, and is this connecting tube on the earlier models really necessary?

ED in MO

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Posted

hmmmm.. only if you want to be able to bolt them onto the wing.... :lol: which tube are you referring to Ed ??

:BC:

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Posted (edited)

hmmmm.. only if you want to be able to bolt them onto the wing.... :lol:/>/> which tube are you referring to Ed ??

:BC:/>/>

Sorry for not being clear - the early struts had a cross tube connecting the two strut tubes at the wing end of the struts - like the center bar in an "H". Some later model struts I saw were just two seperate tubes without this connecting tube - so, is it really needed, and why?

I'm not talking about the jury struts.

The Pipers have two independent struts, and no connecting tube.

ED in MO

Edited by Ed In Missouri

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Posted

Ed, I would say they its more like the cross bar on an "A" rather than an "H" but hey whos to judge. Anyways i've had the same thought as i currently have the small 3/4" lift struts and was thinking of going with two separate ones and add the heim rod ends on both sides rather than just one. I saw these http://www.ebay.com/itm/Kitfox-Aircraft-Strut-Set-/121021750195?_trksid=p2047675.l2557&ssPageName=STRK:MEWAX:IT&nma=true&si=KnKIwhytIX9zuYZ%2BGt2Ltxemi5E%3D&orig_cvip=true&rt=nc on ebay a while back and think something like this may be nice. any thoughts?

-Robert-

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Posted (edited)

Ed, I would say they its more like the cross bar on an "A" rather than an "H" but hey whos to judge. Anyways i've had the same thought as i currently have the small 3/4" lift struts and was thinking of going with two separate ones and add the heim rod ends on both sides rather than just one. I saw these http://www.ebay.com/itm/Kitfox-Aircraft-Strut-Set-/121021750195?_trksid=p2047675.l2557&ssPageName=STRK:MEWAX:IT&nma=true&si=KnKIwhytIX9zuYZ%2BGt2Ltxemi5E%3D&orig_cvip=true&rt=nc on ebay a while back and think something like this may be nice. any thoughts?

-Robert-

I didnt go to look at your reference yet - my puter is about as fast as a snail today - But, Yes, I want to make mine 7/8 with .058 or .065 wall connected to a short stub of the old 3/4 fitting at the fuselage, and insert another short tube inside of the old tube at fuselage fitting before welding the new ones on, and use rod ends at wing connects - best rod end I can find in Spruce is 3/8 threads and 5/16 hole ($17 each) - that should work - believe this is BIGGER than what was tested by Kitfox for about a 15G proof test, except they kept the 1/4 inch bolt, which bent. The rod end broke at 15G.

I can re-use my wood fairing strips on the new struts with a little sanding and epoxy.

The strut fitting at wing is too wide for rod end - so adding washers as spacers should work with the 5/16 bolt.

Dont really think the cross piece is necessary unless some engineering type person tells me why.

Thanks,

ED

get the Aurora rod end equivalent to the Heim - Lots cheaper.

Edited by Ed In Missouri

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Posted

Talked to John McB today at Kitfos - They wont sell the strut end that attaches to the fitting at the fuselage - so rather than cut my old struts, have decided to make new fittings for the new struts - that way my old struts can go with the KF-1 copy fuselage and stuff I need to sell. Looked at several photos of Kitfoxes, and all looked like they have the "A" tube between the struts at the wing end.

ED in MO

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Posted (edited)

sounds good Ed, keep us all posted on your progress as I may borrow your idea once I get that far

-Robert-

Edited by High Country

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Posted (edited)

sounds good Ed, keep us all posted on your progress as I may borrow your idea once I get that far

-Robert-

Something you might consider too - I am moving the pitot tube to the rib next inboard to the strut fitting - already broke 2 of them - going to wait until ready to cover to put another one on.

I have to move it forward anyway since I extended the leading edges 4 inches.

ED in MO

My plan - unless someone has a better idea, is to make the lower fittings, buy 6 tubes, make 4 threaded inserts for the rod ends (3/8-24 x 5/16 hole), call my flying buddy for help, set up my fuselage and attach wings with pvc pipe supports under them, set the dihedral and warp, and measure and cut the tubes to fit, then pin them together and take to welder, since I dont weld anymore. Then hope I did it right!

If I had not raised my cabin crossover attach tubes 6 inches, then I could just use the old struts as a pattern, but now mine have to be longer and the angle changed slightly.

ED

Edited by Ed In Missouri

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Posted

If I were building my own lift struts:

  1. I would make them out of streamlined tubing and be able to forgo any farings
  2. I would use only two threaded adjustments instead of the Kitfox design four - Avid only used one (Remember they are the weak link in the system)

Your idea of locating the pitot tube inside the wing to strut attachment, to protect it, is a golden idea.

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Posted (edited)

If I were building my own lift struts:

  1. I would make them out of streamlined tubing and be able to forgo any farings
  2. I would use only two threaded adjustments instead of the Kitfox design four - Avid only used one (Remember they are the weak link in the system)

Your idea of locating the pitot tube inside the wing to strut attachment, to protect it, is a golden idea.

I already have the wood fairings and the streamlined tubing costs a lot more than round, and weighs more too.

I actually have an old set of J3 struts, but they are way too heavy.

I am afraid that I might need an adjustment of the dihedral after welding - really would like only 2 rod ends, and guess if my adjustment was off, then I could cut the end and put a rod end on it.

Thanks,

I cant take credit for moving the pitot - that idea was given to me by someone on here.

ED

Edited by Ed In Missouri

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Posted (edited)

Ed, I would say they its more like the cross bar on an "A" rather than an "H" but hey whos to judge. Anyways i've had the same thought as i currently have the small 3/4" lift struts and was thinking of going with two separate ones and add the heim rod ends on both sides rather than just one. I saw these http://www.ebay.com/itm/Kitfox-Aircraft-Strut-Set-/121021750195?_trksid=p2047675.l2557&ssPageName=STRK:MEWAX:IT&nma=true&si=KnKIwhytIX9zuYZ%2BGt2Ltxemi5E%3D&orig_cvip=true&rt=nc on ebay a while back and think something like this may be nice. any thoughts?

-Robert-

I finally got puter running better and looked at the reference you gave. I saw these before they sold - think they are stabilizer struts instead of wing struts from the price and looks of ends. Cheap price - rod ends would cost that much alone. I tried to bid on them, but "Flying Fish" has me blocked, since I got pissed off when he sold me a voltmeter with a cracked housing and I gave him some bad feedback.

ED in MO

Edited by Ed In Missouri

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Posted (edited)

If I were building my own lift struts:

  1. I would make them out of streamlined tubing and be able to forgo any farings
  2. I would use only two threaded adjustments instead of the Kitfox design four - Avid only used one (Remember they are the weak link in the system)

Early Foxes only had one also - Now, if you want only two - which two?

And, if I remember the testing right, the rod end failed at 15G - and, I believe that rod end was smaller thread than I am planning.

I'm not stressed for 15G. Well, maybe I was with 2nd wife????/> "Thank God and Greyhound, she's Gone!" That was a great song by Roy Clark!

ED in MO

Edited by Ed In Missouri

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Posted

We used adjusters on the rear strut arms on the hybrid we built. I have the oem Kitfox struts for my project.

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Posted

We used adjusters on the rear strut arms on the hybrid we built. I have the oem Kitfox struts for my project.

How did you like the adjustors on the rear, I was thinking about doing them on each front strut attach point than you could tip the leading edge up or down as necessary. on one of my wings i currently have to pick up slightly on it to slip it into place to install the pin and thought that by having the adjustment in the front i could adjust this out of it.

-Robert-

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Posted

How did you like the adjustors on the rear, I was thinking about doing them on each front strut attach point than you could tip the leading edge up or down as necessary. on one of my wings i currently have to pick up slightly on it to slip it into place to install the pin and thought that by having the adjustment in the front i could adjust this out of it.

-Robert-

I am inclined to agree with you - but still thinking about 4 - believe the greatest load is on the rear?

ED in MO

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Posted

you can adjust the wing line up / pin install with the rear adjuster. The biggest thing is will it fly level hands off. I would much rather tweak the trailing edge instead of the leading edge, although right now, I would love to be able to pull some of the washout out of my wings.

You dont see trim tabs on the leading edge of anything.. Just my .02 and that aint worth much :lol:

:BC:

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Posted (edited)

you can adjust the wing line up / pin install with the rear adjuster. The biggest thing is will it fly level hands off. I would much rather tweak the trailing edge instead of the leading edge, although right now, I would love to be able to pull some of the washout out of my wings.

You dont see trim tabs on the leading edge of anything.. Just my .02 and that aint worth much :lol:/>/>

:BC:/>/>

So what happens if I weld solid on the front and my dihedral is off on one wing? Fly with one wing low? Fly with stick off center? make adjustments to aileron controls instead of correcting dihedral at the strut?

Not trying to be sarcastic - real serious questions about this.

My wings arent finished, and I'm already wishing I had built them without that much washout.

ED in MO

Edited by Ed In Missouri

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Posted

Good points Ed on the dihedral. I was thinking more in terms of adjusting the washout to fly hands off, not being far enough out to affect overall dihedral.

:BC:

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Posted (edited)

Good points Ed on the dihedral. I was thinking more in terms of adjusting the washout to fly hands off, not being far enough out to affect overall dihedral.

:BC:/>/>/>/>

Was thinking I could probably get within 1/4 inch or so, and dont think that would be noticed much on either - but very costly to redo without adjustment ends - so want all opinions before I cut and weld.

I've got elevator tabs for trim.

Thanks,

ED in MO

Another question: With the 1 3/4 washout on the old wing - Kitfox says to set the spars for 1 degree dihedral (thats about 13/16 block on end of 48 inch level) and (I have to check book) I believe, make the washout same on both wings - looks like there should be more precise figures on that?

ED

Edited by Ed In Missouri

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Posted

For the dihedral, set your wing tips on stands to the desired set and measure the length struts you need, then build a jig so that the bushings on the ends are exactly the same distance between, boom, you're there.

Adjusters belong on the rear in order to adjust the trailing edge to keep the dihedral (looking) symmetrical.

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Posted (edited)

For the dihedral, set your wing tips on stands to the desired set and measure the length struts you need, then build a jig so that the bushings on the ends are exactly the same distance between, boom, you're there.

Adjusters belong on the rear in order to adjust the trailing edge to keep the dihedral (looking) symmetrical.

Can do that, but how do I know the trailing edge is close enough to (what?) to adjust?

Actually, instead of a jig, I am going to set dihedral and rivet the ends of the struts and take it to welder.

Ed

Edited by Ed In Missouri

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Posted

Can do that, but how do I know the trailing edge is close enough to (what?) to adjust?

Actually, instead of a jig, I am going to set dihedral and rivet the ends of the struts and take it to welder.

Ed

1. You adjust during flight testing to correct heavy wing issues

2. I don't understand the riveting idea. How do you rivet a bushing to the end of an elongated (squashed) tube? If you build a jig you can make two complete struts exactly the same, making your dihedral equal.

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Posted (edited)

1. You adjust during flight testing to correct heavy wing issues

2. I don't understand the riveting idea. How do you rivet a bushing to the end of an elongated (squashed) tube? If you build a jig you can make two complete struts exactly the same, making your dihedral equal.

Jigs cost money - rivets are cheap - Docs wont let me weld anymore - dont plan on squashing 7/8 inch tube - just insert the threaded end into it and rivet, or put a screw into it to hold it - could do same with wraparound end like early KF too.

ED

P.S. My airframe / wings, etc, were not welded in a jig like the factory built - Could be that one strut has to be a different length to get the same dihedral / warp.

Edited by Ed In Missouri

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Posted

Well, my plans are set - I got four, 7/16 thread / 5/16 hole, rod ends, which are a lot heavier than Kitfox uses, so I can set up struts and adjust if need to, and confident I wont break them. You wont find this size in Spruce. I got them, NOS, on Ebay cheap!

ED in MO

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Posted

     Old thread I know, but since I am looking for older information I will add my 2 cents. Look for Carlson Aircraft they sell streamlined aluminum extrusions for struts, I know one being put together with a set he is waiting for the DAR now, I Got side tracked building a Wittman Buttercup and now have hangar space so both airplanes are sitting side by side being bult. I am spending time on both aircraft at once, the Avid will be finished first, I need to make rudder pedals bend a new firewall and freshen up my motor, I took a taildragger lesson in a Kitfox and got bit by the bug again.

     My problem is I need a second set of hands to build with, building alone is just a little difficult. I have a whole airport to myself most days and I need a hand once in a while.

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