homemade adjustable lead-outs

[Paul Kobe]

Hi
I've made some adjustable lead-outs based on BMJR Super Chief.  Each line can move separately about 3/16" increments by moving the eyelets through holes.  So the spread from the up/down line can moved independently forward or back or spread further apart. So the line separation could be very close or spread about (3/16" to 2+").  I have Brodak ARF Cardinal and 38 Special with adjustable lead-outs.  You just loosen the nut and you can move them forward or back.  The line separation is fixed at about 3/4". 
How important is line separation?
How important is independent line movement?
I plan on making adjustable lead-out for a Brodak Fancy Pants.  The fixed lead-out line separation is about 2.5".  I'm guessing a Brodak lead-out kit will have 3/4" separation.  ?
Does anyone have a design for a home made lead-out?  I figure I would base one on the Cardinal lead-out.  I'll need to figure out what material to use and how far about the line should be.  Any suggestions?  Thank You

[John Park]

Bob Gieseke used the eyelets-and-holes system, stating (in an article I once read) that this enabled you to 'trim for either line', but gave no explanation of the benefits this would confer.  I use the sliding block system, invariably running in a 1/16" ply track, ply being easy to glue securely in place in the tip. For the slider, I've used whatever I've had to hand: a strip of steel or brass with copper or brass tubes for the leadouts and a nut soldered on for the clamping screw; or a piece of 1/4" Tufnol, Paxolin or red fibre with the copper tubes for the leadouts force-fitted and a blind nut for the clamping screw.  I've settled on a leadout spacing of one inch, and never had any problems with the line connectors catching one another.

[L0U CRANE]

I do not consider the line separation at the tip to be an aerodynamic factor - except - they shall not 'hang up on each other'!

In terms of trimming, remember: the midpoint between leadout guides is, basically, where line pull aims to the CG. That midline shifts as force increases on the line that moves a control surface out into the airstream. (...and unless total pull changes, that means the other line 'feels' as much less pull at the same time  The "Netzeband Wall" is hit when we can't put enough pull on the necessary line to get the model to 'go there.' The smaller the separation between leadouts the less that gap affects your input, but the more chance of fouling the clips...

A wide separation, as shown on many old, old model plans, can involve pitch input if you move the handle forward or aft of the  theoretical direct line from handle to CG. (Many early plans showed the guides at the width of the bellcrank, and the leadouts usually perpendicular to the fuselage axis. Not good...)

For me, a slider with an inch between leadouts has been comfortable and dependable.

[Ken Culbertson]

Bob Gieseke used the eyelets-and-holes system, stating (in an article I once read) that this enabled you to 'trim for either line', but gave no explanation of the benefits this would confer.  I use the sliding block system, invariably running in a 1/16" ply track, ply being easy to glue securely in place in the tip. For the slider, I've used whatever I've had to hand: a strip of steel or brass with copper or brass tubes for the leadouts and a nut soldered on for the clamping screw; or a piece of 1/4" Tufnol, Paxolin or red fibre with the copper tubes for the leadouts force-fitted and a blind nut for the clamping screw.  I've settled on a leadout spacing of one inch, and never had any problems with the line connectors catching one another.

I questioned Bob on that and he explained to me that there were times when the line position for insides was different than the one for outsides.  What he never told me was what those conditions were.  Some days he would move them every flight.  In the years I flew with him I am not sure he ever flew the same trim configuration twice. I never liked his method because I could feel the bind from the long tubes in wind.  I prefer the fixed separation (3/4") sliding type with a center screw.  Super easy to make.

Ken

[John Leidle]

   Hi Paul,
  A while back I noticed one of the guys in the club used a wingtip with a 3 inch slot & maybe 8 holes for an eyelet about 1/4" between holes I believe he use this as opposed to a slider for more combinations. At the time he was the best pilot in the area. So almost always I've followed suit.
         John L.

[Ken Culbertson]

   Hi Paul,
  A while back I noticed one of the guys in the club used a wingtip with a 3 inch slot & maybe 8 holes for an eyelet about 1/4" between holes I believe he use this as opposed to a slider for more combinations. At the time he was the best pilot in the area. So almost always I've followed suit.
         John L.

This is the method Gieseke used.  Never saw one of his planes any different.  Some here still use it.  I could never get the holes lined up and I didn't like it all that much better.  I do remember one guy copying Bob that thought he could switch the down line from front to back.  Don't know if he ever figured out what all that stuff was rattling around in his inboard wing.

Ken

[John Leidle]

  Ken,
   I have had a few failures making these, off alignment like you say & the little pieces of wood chipping away...  I'm not sure what this guys  does today he may use a slider .
         John

[gene poremba]

 Im building a Pat Johnston Mustang and Pat included the multi hole style in his kit. I use the multi hole type on several of my other models and like it......Gene

PS, the holes and slots are lazer cut.

[Paul Kobe]

Thanks all.  I've worked a set out with 1" space with and a center bolt with a blind nut. 
Not much room to work with on the Fancy Pants. 

Thanks again