kitfox classic 4 speedster tail problem

i everybody,im now in progress to install all ribs in my vertical and rudder ..so all my vertical was done,but yesterday when i check to starting installation of rudder ribs .i found a little problem...:confused:on my construction book i have two plans ,one for speedster and the other is for model-4 1200...the problem is ....on speedster plan.they said to put a space of 2.32 at bottom and 1.52 at the top..but it"s impossible for me because the rod end at 2.32 is completly out of bushing....and on all plans he have 4 rod end and on my tail only 3....????
maybe because is early model...??

so for my tail the only solution i think is to trim all ribs on rudder maybe 1 inch +/-...

any suggest will be welcome...i dont think i happen only at me...???

I dear JF...i think that's problem is happen only at you...:D

Hi JF

My manual is dated 2003, and shows the Speedster tail with 3
bushings on the vertical. I adjust the rudder to tailpost space
before fitting the fiberglas fairing, Tube to tube dimension has
allways been able to achieve. Post a picture if I don't understand.

Phil

I have a Classic 4 manual from 1994. It shows 4 rod ends to attach the rudder. Top three rod ends are part number 93004 (3/16" x 10-32 rod end). The 4th (bottom) rod end is part number 93001 (3/16" x 1/4"-28). Bigger than the top three.

Now, in 1996, Old Skystar sent me a revised "Classic IV Fuselage Assembly" (Document P/N 10192.000). This new manual shows only three rod ends to attach the rudder. All three are the bigger part number 93001 (3/16" x 1/4" -28 rod end)

Maybe your rod ends are the wrong part numbers.

if i dont put 2 3/8" at the bottom the rudder can't make any move...and if i put 2 3/8" my rod end was to short...i gone take some pic to show you...

i put small video to show thw problem....thank's to all

http://www.youtube.com/watch?v=IcuwZLCjD8c

It appears that the bushing the rod end screws into is too short. The bushings on my classic 4 stick out about 7/8 inch past the rear of the fuselage tail post which is near even with the center of the cutout in the rudder stop tabs.

This one has just the foam gap seal on the tail post. The rod end check nut in this picture is tight against the end of the bushing. The left end of the ruler is near as I can tell where the rear of the tail post is.

:D LOL, Love the video...

Don't have much more to add other than I agree it does appear that the bushings in your case are too short. Perhaps someone cut them off? They should stick out more. Not sure how you would fix that, but you definitely want a lot of the thread holding on all three points and the bushing as far out as possible for strength. Here is the best picture I could find which shows mine. Also a model IV Speedster. Looks like I have about 7/8 to an inch sticking out as TJ measured.

My bushing is only 1/8" out...thats what my problem...if it was like your ,everything was perfect....:(

If i have seen that before to install all rib's and fairing on vertical .i've probably welded an extention to this bushing???

Yes, as long as you could keep it straight.

Maybe thread a new bushing onto an "all thread rod" and then thread the "all thread rod" into the existing bushing to align the new extension piece. Then use a sleeve over the old bushing to the new bushing for the actual welding so you are not welding the "all thread rod" in place. The "all thread rod" would just keep everything perfectly straight for the weld between the sleeve and the old and new bushings.

hi guys, the utube video is great help to see the problem. for what ever reason the threaded post is to short, but being where it is I would not bandade the repair.
I would drill out the stub and fab another and clean the area around the hole and weld in the new one. use the rudder with the rod end screwed in the new post to get the alinement right then tack weld the post and disassembal the rudder from the frame to make a good weld on both sides.
it not as big a job as it looks like and is well worth the peace of mind even if you had to get a welder to come to you. Make sure you use 4160 aircraft grade welding wire. hope this helps.

Quote:

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Originally Posted by jamesmil

hi guys, the utube video is great help to see the problem. for what ever reason the threaded post is to short, but being where it is I would not bandade the repair.
I would drill out the stub and fab another and clean the area around the hole and weld in the new one. use the rudder with the rod end screwed in the new post to get the alinement right then tack weld the post and disassembal the rudder from the frame to make a good weld on both sides.
it not as big a job as it looks like and is well worth the peace of mind even if you had to get a welder to come to you. Make sure you use 4160 aircraft grade welding wire. hope this helps.

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Ya this help...but...i know this is the perfect repair..for doing that i need disassembal the fairing before make the job...and after that my rudder stop dosen't work( look the video)... So i need to make some work on that to...
I just look for maybe a simple solution...

I have a classic fuse but couldn't find a picture on my project that shows the bottom hinge well; this is the closest I have. Have to agree, looks like the tubes are missing or were just cut off. On the bottom the tube is normally pretty long.

Thank's napierm for the pic.....

And one thing....i dont think the bushing were cutting because the rudder stop work with short one...

Quote:

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Originally Posted by Jfquebec

And one thing....i dont think the bushing were cutting because the rudder stop work with short one...

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The rudder stop is an easy fix. It is not too uncommon that a builder files too much off. When I was building almost 20 years ago the factory recommended riviting .040 inch thick 4130 plate on top of the too short stop as the fix for that.

I agree with Jamesmil that you need to make the proper repair by welding in new bushings.

The fairing will pop off easier than you may think.

if someone with and uncovered Classic IV tail could take picture with measurements for you a welder would have no problem fixing it. If you can't find on to get the measurements off the Kitfox factory I'm sure will get you that information.

Considering you have already bonded the fiber glass fairing in place, another solution would be to use a female threaded rod end bearing and use the threaded portion of a socket head cap screw (very strong material) cut to whatever length you need. Strong Loctite on threads of rod end bearing and jamb nut on vertical stabillizer end of threads.

My project is a model 4 speedster. Fiberglass fairing is in place. Going from top to bottom the dimensions are 1/4", 5/8", and 7/8" exposed bushing. My rudder is not installed yet so if you need photos I can get them. This airplane is formerly N91KS which was the factory demonstrator during the skystar days.

To get those bushing to line up just right is going to take a jig. They have to end at the right place in x, y, and z. Any welding will make them crawl around more than you would expect.

Just saying....

If i weld new bushing ,i put more longer than what i need ,,after welding make all thread and after i can take mesurement to cut them more close a possible..

Thank's to all for your reply and mesurement ..i do the job when the montain of snow has melted...:cool:
Beacause is very hard to walk in deep snow with heavy welding machine..

Quote:

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Originally Posted by Jfquebec

If i weld new bushing ,i put more longer than what i need ,,after welding make all thread and after i can take mesurement to cut them more close a possible..

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Yes, you can cut them to length.

But think 1st about left and right. They have to be very close in line to be a good hinge.

Next think about up-down. Have to be in the exact spots as the rudder.

Next think about being perpendicular both left-right and up-down so length adjustments don't matter to alignment.

Think about a good stiff jig to make it right.

FWIW.

I agree with you napierm...that's very important...

Hi,
mrbill's idea sounds easiest and "aligned" . I like his idea of using a female threaded rod end bearing, and a piece of quality threaded rod to extend the short bushing. This might be helpful at the very least for setting up all the bearings into alignment.

JF, maybe you can just order a rod end that is an inch longer so it will reach all the way to the bushing?

Quote:

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Originally Posted by Esser

JF, maybe you can just order a rod end that is an inch longer so it will reach all the way to the bushing?

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I dont think it is very safe with 1 1/4" of this small rod......:eek:
Maybe with small bushing on thread between the bushing of tail post and head of rod end?...:confused:

Quote:

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Originally Posted by Jfquebec

I dont think it is very safe with 1 1/4" of this small rod......:eek:
Maybe with small bushing on thread between the bushing of tail post and head of rod end?...:confused:

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Meh... You still have a weak link where the two bushings meet and this might actually be worse as it could concentrate the side load stress at that point with greater torque coming from the longer rod end.

What I was saying before is to use something threaded as a jig to extend the bushing and weld a sleeve around the junction of the new and old bushings. This would keep everything aligned perfectly. The sleeve would be welded to the tail post and bushing and could extend almost as long as the bushing and also be welded near the outer end. You can cut out part of the fiberglass for a small access area to where you need to weld and hysol it back later.

If you decide to drill out the old and completely install new bushings you should thread them first and install the rod ends. To keep everything in one axis run a 3/16" smooth rod the same length as the rudder through all three to keep them in axis and keep the distance needed from the tail post while you weld everything in place. I suppose you could just use your rudder to do the same thing and keep them all aligned.

JF I like GeoWitz idea too. I drew a picture and I think this is what he means.

http://i1042.photobucket.com/albums/...ps41aaee26.png

The red is the existing bushing.
Green is your rod end.
Purple is a reenforcing bushing.
Brown is a non threaded bushing that slips tightly over the existing bushing and the reenforcing bushing.
Blue is where you would weld.


If I were to do this myself, I would first put the brown bushing over the red bushing, and then I would hammer in my reenforcing purple bushing. But my purple bushing would not be threaded.

I would then weld the oversized brown bushing to the red and purple bushing. After that, I would tap threads into my purple bushing by going through the back side of your existing red bushing that way you chase the existing threads perfectly. Once the threads are all perfect I would then insert my rod end.

Esser - Beautiful! Exactly what I was thinking.

I guess in a perfect world if you really had the time and drive you would preferably drill out and weld in new bushings. However, my concern with that is keeping everything perfectly lined up. Perhaps if you drilled everything out perfectly and kept your drill perfectly centered the new bushings would slide in without slop and self align.

Thank's Josh for your plan...

Attachment 4768


i make this... it's work for the first on but for the second and third...not...

so when i coming back to work i do the job,,,with picture ....

thank's to all

Attachment 4769

Looks good JF...goodluck!

so...after more reflections..i take decision to remove the speedster rib's..:(
but :eek: i decide to check if it work with the rib's one inch inside the rudder,before to remove that.....
so yerterday i gluing the first and last rib's in rudder and i try for 30 degre of movement .....the result it's not bad...:D...i take some pic to show you later..maybe tonight..

that's looking very good..
i need to move all rib's in rudder to the rear like that
http://farm9.staticflickr.com/8272/8...e7ebd9e0_z.jpg


i re drill a 3/8'' hole at the tip of rib when i locate is position with the fiber fairing
and after i trim each side ....
http://farm8.staticflickr.com/7293/8...c3a9aae0_z.jpg

to make sure all's fit correctly i glue the first rib and the last one to make sure i have the 30 degre of movement...
http://farm8.staticflickr.com/7284/8...ea90de28_c.jpg

i dont check this solution in first because the gap between the vertical and rudder are to much versus normal speedster tail......but it better like that than nothing....thank's to all for your interest to my problem...

and a small video...:cool:

http://www.youtube.com/watch?feature...&v=uZ9df5I9C1s

I wish I had checked the fit and movement of my rudder before covering. I thought, what could go wrong? Looking at the video, I don't feel so confident anymore. Well, we"ll see.

Quote:

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Originally Posted by mr bill

I wish I had checked the fit and movement of my rudder before covering. I thought, what could go wrong? Looking at the video, I don't feel so confident anymore. Well, we"ll see.

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You can have easy 1/8"to 1/4" of adjutment after...with the rod end and his nut.....

Looks like that more or less will work mechanically. Your choice, but I would have still fixed it with extended bushings. Now the hinge rotation point is at the front of the rudder leading edge so you have to have gap to prevent interference as it swings where as if it was fixed as designed you would have the leading edge pivoting about the hinge centered at the radius of the rudder leading edge and thus no changing gap space or interference as the rudder swings. I think you may regret doing what you did when the gap looks funny after everything is done. Fixing the bushings as designed is a little work, but I think it would be worth it. Just my opinion. I'm sure what you got will be airworthy.

Quote:

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Originally Posted by Geowitz

Looks like that more or less will work mechanically. Your choice, but I would have still fixed it with extended bushings. Now the hinge rotation point is at the front of the rudder leading edge so you have to have gap to prevent interference as it swings where as if it was fixed as designed you would have the leading edge pivoting about the hinge centered at the radius of the rudder leading edge and thus no changing gap space or interference as the rudder swings. I think you may regret doing what you did when the gap looks funny after everything is done. Fixing the bushings as designed is a little work, but I think it would be worth it. Just my opinion. I'm sure what you got will be airworthy.

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just before to starting to remove all ribs in vertical i look some pictures of normal(flat) tail...and the gap between is about 1'' to 1 1/2''....so that what append in my brain:eek:....the gap space like i did it's mucho better....and my tail is really desing like that..i dont know why..but i have 2 type of tail in my book...one with 4 long bushing..one with 4 short bushing..mine are 3 short bushings...and like that everything work great ...i have 30 degre of movement and all my rod end are tight...if i but that with long bushing i need to modify the stopper .....so after talking with some old pilots....(Cub Pilot)..i decide to make less modif i can...for the time to do and what it give..(better autority at low speed ?)...but finally it dont find that to bad..:cool: