LSaupe

Getting ready to install an ELT prior to the AW inspection.  Just looking for functional and low cost, preferrably without needing to add an external ant.  Just need to check the box.

Any thoughts?

Possibly this one, thought it looks like it needs a permanent external ANT installed?  If so, can the antenna stay within the confines of the fuselage?

http://store.leadingedgeairfoils.com/product_info.php?products_id=6469

Quick question:

My Model III build manual (Fig W-28) instructs to add AN960-816L washers to either side of the ball joint.  I was anticipating something that mate with the  An4-13 A bolt (1/4" vice 1/2").

Is the washer listed correct?  If so, this must slip over the ball bolt boss then?

Larry S.

Hi Doug and Ed:

Yep, the wings were not mounted and folded prior to covering and painting the fuselage.  Actually, it wasnt even a consideration (didnt realize it was a concern).  Just assumed things would go together well (which they had up to this point).  This is my first rodeo so to speak, so much to learn in that department.  I did work with several local builders on this project, however, (none of them with Kitfox/Avid experience) and the topic never came up.

I do appreciate the concerns over any mods, and believe me, I am very cognizant of those concerns as well and what performance effects might be out there as a result.   Any changes would be very measured and as minimal in nature as possible.  Hopefully I can rig my way out.

I have seen a few instances on a Google search where others have had the same binding problems with attempts to use flaps on the earlier Kitfox's.  Maybe a case of tolerances stacking up?  Who knows.  Will get a chance to play again next weekend and sharpen the pencil a bit.

Larry

Hi Jim:

The original holes are predrilled.  I did have some recently purchased/new HF3 ribs and they are in the same location.

Gonna try the re-rig again when I get it out next week to see if I missed anything and will increase my gap to 1+3/4 vice 1" for the neutral setting and see what happens.

If no joy will set the flaperons forward one hole and see how it affects slot distance and other things.  Hopefully something will turn up.  If they do go one hole forward I would need then to trim off the tails of the ribs as they would prevent folding the flaps vertical (rib contact on top of the flap).

Or... I could live (maybe) without being able to use flaps or fold the wings.  Worst case scenario I guess.

Is there any chance the Model I, II and III had different flap geometries?  Maybe in cord and/or bellcrank length?  Reaching at straws; in case I may have the wrong set of flaps here.

I don't know if this was mentioned already, but how was it determined where to drill the holes in the rib tails for the flaperon hangers? If the holes were 1/4" closer to the back of the wing the control rod would probably clear. Looks like you have 1 7/8" from the back of the wing to center of first hole. Maybe others can measure theirs and see if they have less. Just got back from the garage, I measured my Avid Flyer MK IV and the first hole is 1 1/4" from the back of the wing. That doesn't prove that this is your problem. By the time the Kitfox 3s came about, the design wasn't quite as close of a copy of the original Avid. But that being said, my control rods didn't hit the tubing like yours does. Jim Chuk

PS just looking at it some more, and one possible fix might be to cut off and re weld the bottom tangs on the control rod 90 degrees from where they are now. That would rotate the top 90 degrees and give you an additional 1/2" of clearance. Maybe that would cause another problem, I'm not sure, but it might be worth looking at.

Thanks Jim.  Actually, the aft holes are preset at the factory.  The flap hinge is then installed, the bracket rotated to 50 degrees, then the forward hole located/drilled.  A 90 degree rotation (or similar) on the control rod might help a great deal.  

Fabulous stuff there Doug!  Thanks!  Time to do some more digging.

Turtle deck slots and nylon bushings have not yet been cut/fit (which may turn out to be a positive in this case).  If need be, I can live without the folding clearance issue.  Seems like a dihedral change would be needed then might stress the root pins (maybe not).  Opening up the flap neutral position to 1 3/4" would definetly help.  Time to start verifying parts.

Thanks again for taking the time out of your schedule.

Larry

Larry,

    I have an idea of how to move the rod / belcrank attach point one diameter toward center of fuselage if you cant bend belcrank -

I would have to draw it to post it - Still think bending is best - But Wait - I just saw something that don't look right.

EdMO

 

     Something in that #2 photo just don't look right - the belcrank elbow should be well INSIDE of fuselage tube if wings are pinned in place - the round part that is riveted to the flaperon tube HAS to sit inside the nylon bearings, and it looks like the elbow is outside of that area and would keep it from rotating.....   It's hard to tell from the angle of the photo.

Larry,

     Can you take a photo with wings pinned, and looking straight down at the belcrank?

And, check that 5 3/16" measurement that Doug listed?  You may need more than that for some reason?

Hi Ed:

Actually moving to the center would make things worse and the green crossing tube (~ 45 degrees in the pic, lower right to upper left) is the issue.  Here is another shot which also shows the maximum amount of deflection at impact (which in this case is full left stick). Flaps at full up/rod down in this pic.  Or.. would you exepect to see any more deflection at full turn with flaps?  Probably tough to see in the image.

Cant get the bird back out for about a week (lives in the garage right now, takes two to unfold plus would have to put the flaps back on).   Will shoot more when I can if a re-riiging check shows no improvement.

 

Thanks Dusty, I stand corrected. I had to disconnect the flaperon control rods when I folded my KF3  because I installed my baggage sack with a hard floor. Absent this, it would not be necessary.

 

Larry -

• is the measure between the inboard end of the flaperon and outside tab of flaperon control horn belcrank correct (approx. 5-3/16")?
• have you leveled aircraft fore and aft, secured control sticks perfectly vertical and confirmed that the FBK-7 control mixer belcrank is level?
• have you then centered the control stick side-to-side, and with the flap handle all the way forward, confirmed the flaperon neutral position?
• have you confirmed that the tops of the FBK-9 individual flaperon belcranks are approximately parallel to the FBK-7 control mixer belcrank?
• have you properly set your flap limit stop (instructions below)?

  How to find the proper degree of flap for your "stop":

   

• first find the neutral flap position as shown on page CF-18 Fig. CF-12, of your Construction Manual and mark that position for the "zero flap" setting.
• move the control stick all the way to the left (or right) until it stops.
• while holding the stick in this position, slowly pull the flap handle up until it starts moving the control stick toward the center.
• when the top of the stick has moved toward the center 1-1/2 inch, that is Max Flap. This step can be completed after you have finished the rigging process on pages CF-17 through CF-19 of the Builders Construction Manual.

 

Doug:

Thanks for the complete and detailed info.  Much more provided there than the Kitfox III manual,  It really covers only about 1/3 of what you have there.  It includes the first 4 bullets you have there, and yes all were complied with.  The 5th bullet (flap stops), I see no reference for in the manual (or am I missing it)?  I have been contemplating how to make one (for both up and down limits).  Any ideas on what might work well?

With the flaps set for CF-12, putting the stick to either the full left or right will allow no movement of the flap handle (I.e. no deployment allowed) before my FCT-25 part impacts the fuselage crossing tubes.  So, as long as I dont deploy flaps at all I can just get the motion I need.

I will try again in a week and a half (Guard duty this weekend) to ensure I havent missed anything. 

Thanks again for all the info on this.  I hear talk of flap setting of "neutral".  Is this the same as flaps up (control rod forward and down)?

What model have you got? It looks to be a 3

Kf3 wings fold without disconnect,due to different geometry and the swivels that you have.

The flapperons pop vertical soon after the wings begin to move but are very close.

Flap lever neutral

Kf4 has to be disconnected,(some kf3 have been retrofitted)due to the simpler better mixer.

Unrelated to your problem but worth mentioning is a bearing that goes under the flapperon and a corisponding bearing on the turtledeck

I would strongly recommend fitting one,as a flutter may develop!

Photo two should this bearing,but the clearance looks about right! or possibly a little big

Thanks Dusty.  Bearing will be next, but wanted to see where things fell out first amd make sure there were no issues (which there seems to be).

Ed:

Image #2 shows the interference.  Gray push-pull tube hitting the bright green fuselage tube.  Same on both sides.  Happens when the flapersons go to a higher angle of attack such as during a turn and/or pulling on some flaps (basically when the bell crank is raised).  The aft-double tube portion hits the green tube.  Almost like the angle is too great on the flaperon bell crank (though it measures out fine) or maybe the flaperon bell crank arm is too short (though I have no dimensions to check againts).  Neither of which have bearing on the folding issue, which I can live with if I need to.

Leonard:

No wing forward sweep that I can see from the naked eye, and I sight right down the total leading and trailing edges the best I can.  Looks straight to me.

Dusty:

Yep it is a III.  My impression was that they should auto fold as a III but anticipated needing to disconnect if need be.

Clearance isnt even close.  Need about another 1/4" or so to make the swing.  What is more concerning is the control rod interference with the fuselage.  Definetly cannot fly that way.

Any chance one of you could check your position relative to my third image?

Flaperon control rods must be disconnected on the Kitfox III before folding the wings. If you place a straight edge along the flat bottom of the flaperon chord, the hole in the control horn should be 1-11/16" above the bottom surface of the flaperon. If you place a straight edge along the top of the ribs, the angle relative to the back side of the flaperon hinge should be 50°.

Thanks Doug.  All those dimensions check out.  I did check those prior to avoid cycling you guys.

Yep, I did disconnect prior to folding and only started the vertical motion until just prior to the final position.

I gotta think the two issues are related somehow.

Perfect!  Thanks TCJ!

Starting to sound like a broken record with all these posts.

Installed the flaperons today only to find that I have interference issues when trying to add flaps or when trying to fold the wings.

It almost behaves like the flaperons are too far back and down.  Leading edge will hit the fuselage tubing when trying to fold and; the main push-pull rods that connect to the bell crank of the flaperons hit the fuselage tubing at any reasonable deflection or when pulling in flaps.

I cant find anything specific on this dimension.  Anyone else run across this issue?  If I try to use flaps the rods will bind against the fuselage, forget any aileron movement at that point for sure.  Locks up solid.  Same on both side of the plane.

I did not do the initial install so unfortunately only have the old manual to go by.  Seems like there was a pre-placed pilot hole that must have been used.

Do you guys see anything obvious?

Flap hitting fuselage:

Relation of bell crank in neutral flying position:

Relation of hardware to trailing edge.

Great info as usual, many thanks!

Yep, that is was I was looking for, thanks Ed.  My manual had the words, but no images.

Is this a special clamp?  My bird is missing all four.  Is this a Adel type clamp?  If so, anyone have a source for these or know material?

Front and rear travel braces?  I have a set on the rear, but where do the forward ones attach?

I assume the answer is no, but has anyone done an engine run with the wings folded (low to medium power)?

Want to do a quick check out (actually see if she starts and runs).  Wasn't sure if doing this folded was a real concern or not.

I do have the instructions.  A bit more involved than the Ivo I ran on my last bird.

Getttg ready to moount a GSC on a Rotax C box.  I see these come with mini torque studs that you locktite in place.

That in effect then uses the only threaded holes I have.  I assume the actual mounting is then done with nuts on the back side?

Seems that it would be tough to verify torque values given stiction of the nylocs (or is this not a concern)

68" 3-blade GSC with 2.62 box.  Plan on starting at 14 degrees unless someone else has good experience with this setup.

Thanks all.  The snag here is that the holes were drilled prior to me aquiring the project.  Not known whether the wings were ever set up on the fuselage (I assume it must have been).  The  rod ends however were loose and not set.  Did my best to get the wings up in a no-stress mode for the root pins then put on the lift struts.  Think I am "close" but understand small deviations can have sometimes large effects.

So... from that stand point, looking to do external checks to make sure are where they need to be. 

Thanks.  So... is 1 degree the correct dihedral setting?  Washout seeting I assume to be that specified during the build process? 

Installed the wings yesterday.  Now the question is, how to set orientation.  My manual (which I think is a partial manual) is silent with regard to verifying correct orientation (such as dihedral, verifying washout  and other cross check points).  Things went together suprisingly well, however, I do see that when folded that one wing tip is slighty higher than the other so know I have (or assume) some fiddling to do.

Is there a measurent or rigging sheet/instructions to ensure I have everything dialed in correctly?

Kitfox Model III.

Many thanks,

Larry