Leadout end stagger

[Dennis Toth]

Do you normally use a stagger for your leadout ends? Seems people at one time said that you stagger the ends to avoid having them lock together. I have done this with several ships and just wondering if it is worth the trouble of getting the lines to line up proper with the stagger?

Best,   DennisT

[Howard Rush]

It's probably a good idea, although it adds some weight and drag.  It has saved a plane for me when I hooked up the lines backwards, which was immediately obvious when I picked up the handle.

Here's a Jive Combat Team tip for you young stunt fliers intending to have staggered leadouts: when you cut your leadouts to length, don't cut the short one first, then forget that it's the short one and cut the second one short, too.  Then you won't have staggered leadouts. That happened on my last two stunt planes.

[Fred Underwood]

And, that stagger is more than you might think at a glance.  If you want to keep stagger at full throw, don't forget to include the length of line wraps and clips, and travel at full throw.  I end up with stagger of about 6" in neutral position to keep clear.

 

[Ken Culbertson]

Most of the planes I have seen with stagger just seem to want to cover neutral with about 3".  To be totally effective you have to cover the full range which is closer to 6"  I don't think I have ever seen one with that much.  IMHO it is one of those things that solves a non-existent problem.  If you wrap your lines properly and use properly formed clips, they just aren't going to snag.

I am sure it has happened but in 50+ years I have never seen one.

Ken

[John Leidle]

   I stagger mine for that reason.
  John L.

[Perry Rose]

With stagger you use a cable handle?

[Dennis Toth]

This is interesting, I think it might depend on the size of the line connector one chooses. I like the medium size scissor clips (once I leaned that to open them to remove from the leadout you simple pull on one side). Wing tip line spacing may also be a factor. If you like really close (3/8" ish) spacing or big line clips then stagger may be more important. I use the independent line sliders and start with a separation of 5/8".

One thing in favor of not using stagger of more than an inch or so is it allows using pre-made standard lines without the need for a special handle wire or if hard point specific cut to fit lines.

I think using say 1" stagger with color coded end marks will help prevent reverse hookup as Howard said and still allow standard purchase lines.

Best,    DennisT

[John Park]

I seem to recall reading somewhere that Bob Palmer used unequal-length leadouts when he introduced the 'over-and-under' leadout guide arrangement on his Mk. 2 Thunderbird.  It would make sense if he did.

[Paul Walker]

Most of the planes I have seen with stagger just seem to want to cover neutral with about 3".  To be totally effective you have to cover the full range which is closer to 6"  I don't think I have ever seen one with that much.  IMHO it is one of those things that solves a non-existent problem.  If you wrap your lines properly and use properly formed clips, they just aren't going to snag.

I am sure it has happened but in 50+ years I have never seen one.

Ken

I had happened to me several times in the past. Nothing worse than heading for that 5 foot bottom  hitting the up and have it hesitate because the clips catch. I switched to staggered leadouts shortly after that event. Just because you have not experienced it doesn't mean it isn't a problem. If your leadouts are spaced an inch apart at the tip, you are probably safe.

And  don't forget the benefit of lines connected BACKWARDS. It will save you from taking off in that condition.

[Ken Culbertson]

I had happened to me several times in the past. Nothing worse than heading for that 5 foot bottom  hitting the up and have it hesitate because the clips catch. I switched to staggered leadouts shortly after that event. Just because you have not experienced it doesn't mean it isn't a problem. If your leadouts are spaced an inch apart at the tip, you are probably safe.

And  don't forget the benefit of lines connected BACKWARDS. It will save you from taking off in that condition.

Maybe I have just been lucky.  I never use crimps.  I have always wrapped my lines.  Recently I also use a shrink tube.  I suspect that you have about 10x my number of flights on your log so maybe my time is coming up!

Ken

[FLOYD CARTER]

It seems to me that a pilot would have his head on some other planet to take off with lines reversed.  A set routine when connecting lines, plus a quick "wiggle" before takeoff will always prevent reversed controls.  Although, I've seen it happen.  But I don't understand it.

[Ken Culbertson]

It seems to me that a pilot would have his head on some other planet to take off with lines reversed.  A set routine when connecting lines, plus a quick "wiggle" before takeoff will always prevent reversed controls.  Although, I've seen it happen.  But I don't understand it.

Apparently they fly stunt on that planet!  I have seen World and National Champions do it.  Remember, the EZ-Just felt the same upside down as it did right side up and there were no tell tale lanyards back then.  Doesn't happen as much except when you hook them up backwards.  Mine are color coded.

Ken

[Fred Underwood]

Most of the planes I have seen with stagger just seem to want to cover neutral with about 3". To be totally effective you have to cover the full range which is closer to 6"  I don't think I have ever seen one with that much.  IMHO it is one of those things that solves a non-existent problem.  If you wrap your lines properly and use properly formed clips, they just aren't going to snag.
Ken

If you look at the leadout position with respect to bellcrank swing, one lead moves out about 2" while the other retracts about 2" giving a fair amount of overlap.  You also need to then include the wrap and thimble of the leadout, the wrap and thimble of the line, and the clip.  Mine is about 6" to avoid those parts from overlapping.  It may be longer than necessary, perhaps Paul Walker will comment on how much he allows.  From what I recall seeing, some of his are similar?

I make each line to the plane, so making a long line and a short one is no more effort that making them the same.  When I make the second line, I have both lines on the plane and adjust the length to neutral handle. You don't have to wiggle the handle to tell if they are backwards with that much line length difference.

But, just my opinion and method, and as they say, YMMV.

[Ken Culbertson]

I know a guy who admitted to working the handle and watching the flippers then took off with the handle upside down anyway. He taught me to only give it UP when you are checking the controls.


Motorman

That cost me a plane.  It was new and the bellcrank overcentered.  Had I given it down it would have unlocked.   I thought it was impossible to overcenter a bellcrank - until thenken.

[FLOYD CARTER]

OK.  Now I understand. 

Some people are mechanically challenged, or else have poor eyesight/

I always do a control wiggle before takeoff.  I can tell the difference between up and down.

My handle is color-coded.  RED means UP

(you can see that my lines are both exactly same length-- well, almost)

[Tim Just]

My VERY recent experience strongly suggests that equal length leadouts are a liability.   The first time it happened I was high enough to wiggle the handle and free the controls.  The second time (25 flights later) I was on the backside of the triangles.  Frustrating as I only had 298 flight on this model.

In hindsight I could, should have increased the line spacing to one inch as Paul recommended in a previous post. I will have stagger in my next model.

It hit hard enough to destroy just about everything.  The motor, battery and speed control were all destroyed.  Even the rudder trim pushrod failed as it was centered pre Impact impact.  My Igor propeller was spared as I was saving it for Muncie. 

Tim

[Ken Culbertson]

My VERY recent experience strongly suggests that equal length leadouts are a liability.   The first time it happened I was high enough to wiggle the handle and free the controls.  The second time (25 flights later) I was on the backside of the triangles.  Frustrating as I only had 298 flight on this model.

In hindsight I could, should have increased the line spacing to one inch as Paul recommended in a previous post. I will have stagger in my next model.

It hit hard enough to destroy just about everything.  The motor, battery and speed control were all destroyed.  Even the rudder trim pushrod failed as it was centered pre Impact impact.  My Igor propeller was sparred as I was saving it for Muncie. 

Tim

It appears that I may be in the minority here.  Maybe it is the way I wrap them that has led to never having this happen to me (I never use crimps) or maybe I use more spacing (3/4 - 1") between lines at the guide or maybe I have just been incredibly lucky.  In any case, staggering them can't hurt.  Sometimes when controls lock it is difficult to find the cause since they almost always unlock on impact.  That is why I use floating bellcranks exclusively.  Classical bellcrank mounts leave too many places for a leadout to snag, especially if they are crimped.

Has anybody ever done a camera fixed on the wingtip like some I have seen on fuel tanks to show what happens during flight?  I have often wondered how far out our lines are when they wrap from maneuvering.  Experience in other areas tells me that they will be wrapped at the narrowest point under pressure which is close to the wing then move further out as pressure releases or, ( and this is supported by tons of pictures) they will wrap closer to the handle if the leadout spacing is sufficient.  If they are equal then they will only be touching in level flight then separate in corners. By staggering them a small amount (1" or so) you are removing 3/4 of the contact opportunities and if there are no opposing flats in the connections it would be very difficult to snag.  However, if you have enough spacing and the connectors are as close to the guide as possible then they may never touch at all which points to the most likely cause - a connector got hooked up wrong.  Easy to do if you are in a hurry.  That is why I check them before every flight and try to keep them under tension until I am airborne.

Bottom line - you lost a beautiful ship (aptly named by the way) early in it's life and that is always sad.

Ken

[Dane Martin]

The irony in that photo begs a caption.  Anyone?

Too soon?

[Ken Culbertson]

Too soon?

Check that outboard tip for teeth marks.  This might be the preview for "Attack of the Invisible Air Sharks"

Ken

[Dennis Toth]

Ken brings up an interesting point about line wraps/twists during maneuvers. At takeoff most pilots will start with the lines totally untwisted (I always walk my lines down going out to the handle just to be sure). But during the pattern the lines will get wrapped around each other then unwrap. In the PA pattern the most you get is three wraps after the inside loops. In the Old Time pattern you get five. These unwrap after the outsides are done then you are good until the two inside triangles which never unwrap for the rest of the pattern. In OTS you get one for the wing over at the beginning and one more after the square loop at the end.

This begs the question where does the line wrap reside down the length of the lines? It seems that with wider leadout spacing it would be further inboard away from the clips. How much spacing can we use without a noticeable impact on yaw? It also seems the even with stagger if the leadouts are very close because of the line wrap you could still have a clip/eyelet/wire wrap catch the other line and cause a problem.

So it seems that line spacing is more important than many may have thought. What do you think is the narrowest and widest usable leadout spacing?

Best,    DennisT

[L0U CRANE]

Dennis,

If the space between your leadouts is centered on the correct trail angle, the size of the space should have little effect on yaw.

Unless you swing your arm fore  or aft of the line angle as you input control... that relative yaw can have effect.

Unless your model needs to shift a lot of the total pull to the acting line...

Terms:
"correct trail angle" as found by, say,  a LINE# program and/or refined by in-flight tweaking: the line of "pull" from mid point between leadout guides to CG.

"acting line" the line causing the control surfaces to move to perform the maneuver.

An example? Model pulls 8 lbs with leadout guides 2" apart and properly located. If you require all 8 lbs on the acting line to snap a corner, pull's line of action shifts 1" and increases from that line's load at neutral, 4 lbs, to the full 8 lbs. Neither the distance by which pull is "re-aimed", nor the magnitude of the resulting 'yaw torque'  is large..

These factors only reflect pull and leadout spacing. Other factors, like inertia and aerodynamics, can delay unwanted yaw response  during the extremely brief duration of a corner. Larger figures are less likely to need that much line pull shift and take longer to execute.