Adjustable leadouts ?

[David Fretz]

When planes get loose on the lines above 45 degrees, do I move the leadouts forward or back. Don't have this straight yet. Adjustable is all new to me.

[M Spencer]

Start with a Sky Hook & a spirit level .( Say hang it from the ceiling by the leadouts . Pull Testing in this position isnt to be advised  . )

Why , only the other day , some notable exponent advised 1/8 inch per foot Nose Out . as a Base Setting .

NOW , some say Moveing Em Forward will Improve the overhead eights . ! . Until it gets nasty , then a notch back.

BUT ; theres the ' wheels visually IN LINE . Which denotes its flying square/ tangental and so on.

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THEN theres rudder area ,rudder offset ,  fuselage side area distrobusion , wing assymetry , side thrust , differant props, and maybe a few other considerations .

HOPEFULLY theyre INDIVIDUALLY ADJUSTABLE ? .

Notta Bad Idea is to at least put some ink marker ' incriments ' at the guide . At least for initial tuning . So essentially its suck it and see . And Be Carefull if its not feedingback reasureance.
Though extreme range adjustment may well give you a greater initial appreciation of the result. But back off , fly out the tank , and reset - if the behavior is worriesome .

[Dennis Toth]

Dave,
The basic approach is to first determine the CG location for your particular ship. If it is a kit or plans and the CG is marked, start there. If you are building from your own design or the CG is not shown the rule of thumb is to calculate the rough area of the stab plus elevator, calculate the wing area. Divide the stab/elevator area by the wing area. This gives a % that the stab/elevator is relative to the wing and a starting point for setting up the CG. Get the average wing cord (including flaps) by taking the root cord plus the tip cord and dividing by 2. Take the % stab/elevator times the average wing cord and this give the rough starting point for the CG location (this is usually about the middle of the wing panel span). At this location measure back from the leading edge and set the CG.

For most 35 - 46 size ships, set the center of the leadouts 3/8 to 1/2" in back of the CG (if you have front line up elevator use the 3/8", if front line down use the 1/2"), if 60 size stat with 1/2 to 5/8".  This will give a safe starting point. Now do a flight and see how it feels, next flight move the leadouts 1/8" back and see if it feels better or worst above 45. After a few flights you will find a spot (go in 1/8" moves) that will feel good up top and in level flight without the ship banging on the corners (which could also be due to much tip weight). Good luck let us know your progress.

Best,   DennisT

[Dave Rigotti]

To answer your question.....
Move the leadouts forward to increase line tension above 45 degrees.... Use line 3 program to determine a starting point...

[Ken Culbertson]

Start with a Sky Hook & a spirit level .( Say hang it from the ceiling by the leadouts . Pull Testing in this position isnt to be advised  . )

Why , only the other day , some notable exponent advised 1/8 inch per foot Nose Out . as a Base Setting .

NOW , some say Moveing Em Forward will Improve the overhead eights . ! . Until it gets nasty , then a notch back.

BUT ; theres the ' wheels visually IN LINE . Which denotes its flying square/ tangental and so on.

==================================================================

THEN theres rudder area ,rudder offset ,  fuselage side area distrobusion , wing assymetry , side thrust , differant props, and maybe a few other considerations .

HOPEFULLY theyre INDIVIDUALLY ADJUSTABLE ? .

Notta Bad Idea is to at least put some ink marker ' incriments ' at the guide . At least for initial tuning . So essentially its suck it and see . And Be Carefull if its not feedingback reasureance.
Though extreme range adjustment may well give you a greater initial appreciation of the result. But back off , fly out the tank , and reset - if the behavior is worriesome .

You forgot tip weight! My ships all have lots of rudder area and engine offset.  Never had an issue with overhead tension.  Line drag is also a leading contender.
Sometimes shorter lines help fix this as does keeping them clean.   If the leadouts are where they should be relative to the CG then look to some of these other causes of poor tension.

Ken

[Peter Nevai]

Ok well those answers left me totally confused. Answer one and two are way over over a newbies head and two of them contradict one another and yet another goes into rudder offset,  wing tip weight and engine offset.

So I ask the question again if it gets loose at the top  lead outs forward or back? We can discuss how by much, wing tip weight and all that other stuff later.

[Scott Richlen]

So I ask the question again if it gets loose at the top  lead outs forward or back? We can discuss how by much, wing tip weight and all that other stuff later.

You've actually gotten good advice.  i think the reason some of it is conflicting is because "it depends".   Sometimes it is moving the lead-outs, sometimes it is changing tip weight, and sometimes it is using a different prop.  And, yes, the prop can make a big difference!  And sometimes it is something else.  Different airplanes react differently.

What you should do is make a change, fly, and pay attention to how your flight characteristics changed.  Keep a flight log.

[peabody]

Peter....there is really no generic correct answer....all of the things mentioned contribute.

But think of it this way: most fly counterclockwise when upright. Because we are on strings and flying an almost circular path, the plane is constantly turning left, yet it pointed straight ahead, which means that it is constant yaw. Very few aircraft are designed to fly in constant yaw, and various other forces stop working well when a plane is in yaw.

Generally adding rudder offset causes yaw. As does engine offset.

Some pretty good and famous flyers have flown with the leadouts to the rear....some radically. This results in a plane that wants to "pull" a bunch when level, but the amount of "pull" decreases as the plane climbs (wings aren't level, highlighting the yaw condition. Big props and powerful engines may overcome the tendency to fall in on the flyer, ala helicopter.

When you look at the average of the top guys, you will detect very little rudder offset, or engine offset, and the leadouts will be about at the high point of the wing, some slightly forward. (I believe that Paul Walkers great trim article demonstrates how to get to a pretty good starting point).

I bought a plane that Doug Moon used as a backup the year he was the champ. It barely "pulled" in level flight, and was almost equal high up or overhead. Very pleasant. I cried when she squashed it with the car.

I hope this helps. Don't be afraid of moving the leadouts forward to increase line tension....the strings tug the plane to the left.

[Tim Wescott]

So I ask the question again if it gets loose at the top  lead outs forward or back? We can discuss how by much, wing tip weight and all that other stuff later.

Yes, you absolutely do that.

There's an optimal leadout position: too far forward and the plane is pulled inward by thrust from the prop and lift from the fuselage; too far backward, and the plane is slowed down by drag as the fuselage tries to lift it.  Somewhere in the middle is just right.

I'm not smart enough to know which way is which just from how the plane flies, so when I go to tune this I move the leadouts a bit and note whether things get better or worse.  If they get worse, I move them the other way; if they get better, I keep moving the leadouts in the same direction (unless something else bad happens).

If I feel like some book learning, I re-read Paul Walker's articles on trimming, starting with this one: http://flyinglines.org/pw.trimflow1.html

[Ken Culbertson]

So I ask the question again if it gets loose at the top  lead outs forward or back?

Yes

Not to be a smart ass but it could be either and it is most likely not the reason it is losing tension.  Planes that stay out well overhead rarely (in my experience) pull very hard in level flight.  Changing leadout position to increase it is probably masking the real reason.

Now having said that mark where they are and move them back no more than 1/8" and see what happens.

Just out of curiosity, what are you doing when it loses tension?

Ken

[M Spencer]

https://www.dropbox.com/s/8u66jhcwnx2tk66/Al%27s%20Models%20Book%202.pdf?dl=0

About page 375 , for sore heads . ; trimming ' starts .

Its a bit like sitting in a rocking chair , having a think , and whittling . Usually comes to you .

[Ken Culbertson]

https://www.dropbox.com/s/8u66jhcwnx2tk66/Al%27s%20Models%20Book%202.pdf?dl=0

About page 375 , for sore heads . ; trimming ' starts .

Its a bit like sitting in a rocking chair , having a think , and whittling . Usually comes to you .

This raises a point all of us might be missing.  We use modern power plants all of which respond to a need for more power without the pilot having to think about it.  The one "fix" we all missed is increased power.  Thanks Al.

Ken

[Chris Fretz]

30-40 flights you might have it ironed out!

[David Fretz]

Thanks for the many suggestions. Will work on the Oriental and see what happens.

[TDM]

Sorry for the late reply. If lead outs are too far back over 1.25 in behind the CG the typical feel of the plane is exactly what you did experience, hard pull on level flight that diminishes rapidly even to the top of the loop. If that is the case start to move them forward 1/8in at the time and see how it feels. You will probably notice an increasing line tension on top and perhaps a very slight change in tension at bottom. Keep moving them forward till you max out the tension on top specially for the hourglass maneuver. I like to do loops first then if it feels good I do the vertical eight then the hourglass then four leaf clover, and each time I take note of variations in tension.

Lead outs too far back for example 1.5 or more behind CG good tension at 5 feet, and very loose at 45 and above.

As they move forward the trend is

Good tension at 5 feet, you might start to notice some increase of tension at 45.

The next faze you will experience is some loss of tension at 5 feet but noticeable gain at 45 and above

Lead outs back of optimum but getting close to optimum, good tension at 5 feet a little lower than max tension, but will experience significant increase tension at 45 and above.

Lead outs optimum good tension it feels kind of even all about and max tension possible overhead.

If the model is heavy and pulls too much then consider going in front of optimum which will soften the pull some.

Lead outs in front of optimum the line tension feel will remain even but will start to diminish as you move them further forward.