Line Length

There are times at our local field when an expert stunt flier will say that his plane needs 62 ft lines rather than the 61 ft lines they have just used. Are we being "smoked" or can one really discern one foot line length differences and if so how would you come to the best line length for a given plane?

Richard(who is in need of and about to make up a new set of lines.)

Probably has more to do with trimming for lap time or tension of something. I've cut or added as little as 6" from lines in order to adjust lap times when everything else is working.


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Some days it seems like a coin toss between George Orwell and Monty Python...

>There are times at our local field when an expert stunt flier
>will say that his plane needs 62 ft lines rather than the 61
>ft lines they have just used. Are we being "smoked"
>or can one really discern one foot line length differences and
>if so how would you come to the best line length for a given
>plane?
>

A foot is a very noticeable change.

Brett

>>There are times at our local field when an expert stunt
>flier
>>will say that his plane needs 62 ft lines rather than the
>61
>>ft lines they have just used. Are we being
>"smoked"
>>or can one really discern one foot line length differences
>and
>>if so how would you come to the best line length for a
>given
>>plane?
>>
>
> A foot is a very noticeable change.
>
> Brett


Yeah,
Actually, at 50 mph (which is admittedly slow but easier to calculate in your head) 1 ft of line length (62 to 63 ft) makes a difference of a little over a tenth of a second in lap time which is certainly significant.

Randy C

Three inches is a noticible change on some ships...

Concur. However, 3" is a rather gross adjustment. RJ

I'm not a top flyer. Far from it, in fact. But I can say that a foot or two makes a world of difference.

Marginal OTS patterns on 62' lines became very satisfying after cutting the lines down to 58'.

That was a long time ago. Re-read postings by Buck, Whitely, et al. They know what they're talking about.

Mike Keville
Tucson, AZ
AMA 14220

The first liar hasn't got a chance!

Bob Hunt

>The first liar hasn't got a chance...
======================================
Amen ... from an "also ran". These guys speak the truth.

Mike Keville
Tucson, AZ
AMA 14220

>Concur. However, 3" is a rather gross adjustment. RJ

Yeah, for *you*, sure! I'm really just sport flier, I can't tell the difference.

Brett

It is very important where in the line the extra foot is added. It will have a much greater effect if it is added to the model end rather than the handle end

Yes, that is correct. You must always lengthen or shorten the lines at the model end. By doing this the engine run is not as affected nearly as much and thus you do not need to change the fuel mixture or glow plug as often. RJ

>Yes, that is correct. You must always lengthen or shorten
>the lines at the model end. By doing this the engine run is
>not as affected nearly as much and thus you do not need to
>change the fuel mixture or glow plug as often. RJ

Now me, I always lengthened my lines at the handle end. That way the knots won't cause as much drag as if they were way out there. Four in hand knots work fine for this. (Uh, April Fools Day is over guys. You think we had better watch out. Somebody might believe us.)

Frankly, I've always spliced a five foot length of light weight bungee cord in the middle of each line. Self regulating. The faster the plane goes, the longer the lines get. Keep in mind that bungee cords vary in elasticity - a little experimenting is in order. Do your pull-outs a little higher than normal while you're experimenting.

Ciao;

Wayne

Ok how about a real scenario.

Putting trim flights on the new Saito 40 powered Shoestring.. Think Pat Johnston's P-40 with a Shoestring looking fuselage. With the prop I was running the engine wanted to be really happy at about 8200 RPM. I had great line tension and the airplane seemed happy, problem was on 58 foot lines my lap times were down to around 4.6 seconds and everything seemed cramped.

I made up a set of 62 foot 15's thinking this was probably the absolute longest I could get away with and if they prove a little too long I can always cut them down. Now just waiting for a calm day to try out the new lines. 4 feet is a big change and not real sure the little Saito has enough balls to haul lines that long, but if it all works out, the engine will be happy, the airplane will be happy and the pilot will be ecstatic.

You guys really crack me up. You're all just a bunch of amatures.

I always add my line length in the middle...that way it doesn't effect the engine or handle settings.

Hmm , I wonder if maybe I am doing it wrong then, I usually just add mine to the leadouts, line sets are expensive you know, the leadouts are cheaper to replace,,, heck they are only like you know what,, 2 feet long,, lines are 30 times that!,, these are tough economic times you know,,,,

All you guys have it wrong... You add to the length of one line at the airplane and the other at the handle. That way the knots don't tangle together and lock your controls.

Ron B.
F4Fguy

It's obvious none of you have really thought this through. Line length isn't the correct adjustment at all. Line diameter is the way to go.

Want to go slower; increase line size from .015 to .018. still not enough? Go up to .021. This way you have no effect on the engine and you only need one length for all airplanes, just a number of sets of sizes from .008 to .031. Minor adjustments can be made by changing the size of line clips, coarse adjustment at the plane, fine at the handle.

Yeah, yeah, that's the ticket!

Ron B.

PS: Always make the LO ends at 45°, that way the drag of the ends and the clips is the lowest due to the reduction of frontal area and doesn't change as much with clip size.

Hmmmmm.....
Like the Gieco Geko says.....
Oh Dear!

Randy C

>You guys really crack me up. You're all just a bunch of
>amatures.
>
>I always add my line length in the middle...that way it
>doesn't effect the engine or handle settings.


You must have learnt that trick from the famous Finnish flyer Loof Lirpa.

I have decided to use a micrometer . . .

>I have decided to use a micrometer . . .

Oh, didn't we mention...I think David had the right idea here about adding length to the center. That way you get two knots. At the Nats they will occasionally check your line size with a micromoter while they do the pull test just to make sure. The key here is to give them one of the knots to check. If they check with the micrometer right at the knot, you will always pass the minimum line size requirements--regardless of what size you are really using.

You could also add line length at the airplane end using a crimp splice. Crimp splices are good because you can always see where the line is going to break right after it happens.

And if you splice in a section of .021 line at this point, always make sure the person using the micrometer checks that portion of the line.

(Maybe we should add a section to this forum called "tall tales" or such.)

>Ok how about a real scenario.
>
>Putting trim flights on the new Saito 40 powered Shoestring..
>Think Pat Johnston's P-40 with a Shoestring looking fuselage.
>With the prop I was running the engine wanted to be really
>happy at about 8200 RPM. I had great line tension and the
>airplane seemed happy, problem was on 58 foot lines my lap
>times were down to around 4.6 seconds and everything seemed
>cramped.
>
>I made up a set of 62 foot 15's thinking this was probably the
>absolute longest I could get away with and if they prove a
>little too long I can always cut them down. Now just waiting
>for a calm day to try out the new lines. 4 feet is a big
>change and not real sure the little Saito has enough balls to
>haul lines that long, but if it all works out, the engine will
>be happy, the airplane will be happy and the pilot will be
>ecstatic.


I don't know about the Saito, but when we first started fiddling around with our modified FP 35, we put it on the "standard" 58 foot lines. It worked fine, but lap times were the typical 4.6-4.7. But it had tons (well, maybe half a ton) of pull. So I suggested going longer. We put 67 foot lines on Matt's Stuka powered by the modified FP 35 and lap times were a nominal 5.3 and it hauled freight. Seriously, don 't ever be afraid to add line length. Some set-ups may not have as much tension as others, but you need to get the airplane up to flying speed. If your engine is running good and the plane is flying good and you want to slow down the lap times, try going to longer lines. There is nothing written in the rules that says you have to use any particular line length with any size engine (except you can't go over 70 feet from handle to center of airplane).

Expert Flyer flying at the local field!?

Gee. That's why I make up a few sets of lines, handles and see what length/feel I need. Flying a 40-sized classic non-piped stunter at 53 oz I started out with 60' center to center. I'm trying this weekend 59'6" eyelet to eyelet. I also will try 61' eyelet to eyelet. What I'm looking for is drag, hinging, & lack of control in the coffin corners. Lap speed is not an issue for me.... at this point to the trimming process. No Smoke and no Mirrors

Scott( Becomming a better flyer is asking the right Questions) Riese

I glue the add on lines with JB Weld. I don't have to worry about drag because I file the excess glue to keep weight down while balancing the weight of the two joints, if one is heavier it will mess up the 3rd turn of the hourglass.

Martin