adjustable lead out guides?

[Cody bishop]

how can i install/adjust a adjustable lead out guide and what are the advantages to having one

[Tim Wescott]

how can i install/adjust a adjustable lead out guide and what are the advantages to having one

An adjustable leadout guide is anything that holds the leadouts firmly while letting you adjust them fore and aft.  There's a number of ways to do it.  The two most common ways to do it are with eyelets or sliders. 

With eyelets (or screws), you mount a piece of plywood in the end of the wing, drill a bunch of holes with a slot in between, and use eyelets or screws as guides.  You shove (or screw) the eyelet/screw in the appropriate hole, and that holds the leadouts in place.  The downside with eyelets is that they're subject to falling out if you don't get the tension right on the guides; it can happen in flight and screw up your trimming.  I've never done the screw method (so someone who has, speak up!!), but the idea is to take some suitable screws (probably #4 machine screws), drill holes in them (probably 1/32", to clear 0.027" leadouts), and use them instead.  I believe that you also need to tap the holes in the guide, before sawing out the slot.

With a slider, you use a piece of slotted material (I just make one out of plywood), with a carrier that rides in it.  The carrier has a pair of brass tubes for the leadouts.  Or you can buy the whole shebang from various vendors.  If Brodak doesn't have 'em, I'll be surprised.  I don't keep track of who might do that, because I like building that sort of thing.  You want to use big washers on the screw; if you have too small of a contact area then your plywood carrier will dent, which will keep you from adjusting by less than 1/16" or so.

(Note that the one shown is for a trainer plane with an external mechanism: in a normal in-wing installation the plywood slot gets glued into the wing tip.)

As a variation, some of the top guys use two sliders, one for each line -- I did this on my latest, still-on-the-board plane, but I'm not sure I'll be good enough to tell the difference when I change line spacing.

[Tim Wescott]

The advantage is that you can trim the amount of yaw the plane has in the air.  If the leadouts are too far forward, then the plane will point nose-in, and it'll be light on the lines, especially in the overheads.  If the leadouts are too far back the plane will point nose-out, which will be nice in level flight when it's going fast, but it'll be so draggy that it'll slow down in the overheads and get light on the line.  To get the best overhead line tension, the leadout location needs to be just right.  There are some other compromises that you need to make as you get more advanced, but if you have to ask, the first thing you'll notice is how much more control you have in the overheads.

[john e. holliday]

If a person wants to spend some time reading,  go to the search function and type in 'lead out guides'.  There are many ways of doing it depending on plane design.  I make my own guides as I can make them for what ever plane I'm doing.  In fact there is a series of construction pics showing how to do wing tips with the guide.  But it is winter time and here in my area the temps are 4F degrees out side, temp index with the wind is below zero.  Another place to look is Walter Umland's site,  builtightflyright.  You may even spot some construction series to help out also.  Yes, I'm being lazy in not copying and [posting the ones I can find.