Line Lengths

Some threads have indirectly addressed line length. The top guys with big engines obviously go 70 feet, no decision (that is still the longest legal length, correct?). Line length is not an easy adjustment to fiddle with, as extensions are universally considered unhealthy.

Rethinking, what lengths do you like for 35s, 40s, and up? Longer lines have a clear advantage in maneuvering room, and some associated loss. I have begun to doubt my judgment here, and think perhaps a Flite Streak would do better on 63 or so, even with a wimpy Fox 35. And maybe stretch the FP40 profiles out to 65 or 67. Too much line? Assume legal diameters.

Within the last few years of Stunt News there was an article on finding the "Sweet Spot" for line length.

Watt Moore who is also flying a Legacy 40 with a OS 40 FP flys his on line that are about 4' shorter than mine. Line length has a lot more to do with than just engine displacement. Line length is used to adjust lap times when the engine/prop combo is optimized.

For a number of years we used 66 foot lines on our (modified) 35FP stunters. And we flew at roughly 5.3 second lap times. Yet flying the classic ships with either a Fox 35 or OS 35S, we used 60 foot (handle to center of plane) lines and flew 4.7 second lap times.

With Matt's 61 powered pipe ship we are running about 68 feet. Going longer, with our particular set-up, seemed to lose something. Lap speeds are around 5.3 to 5.4 seconds. Others may go all the way to 70 feet, or people, such as Alan Brickhaus, who likes to fly slow, flies his 61 powered pipe ship on about 65 foot lines and about (way too slow for me) lap times. I remember one of the first times I timed Alan. I thought he had gotten it off too slow, but I was impressed that he still put in an admirable pattern. When he came down the first thing he said was, "Going too fast. I've got to slow it down." It is all a matter of choice and style.

So, don't be afraid to try longer lines, especially if your lap times are particularly fast. We have several sets of lines to try things out to find the best length for us. But even without that luxury, you need to make new lines up periodically anyway. Make up your next set longer, if you want to try longer lines. Fly the plane, and if you like it, you are in business. If not, you can always shorten them back to the length you really like.

Some of you have mentioned flying 6 or 7 different planes in one flying session. If so, you may not like my next suggestion. Others, and we are in that category, will fly only one or two different planes all year long. Many of those in the latter category will set up one set of lines and a handle specificially for that plane. Then you adjust it and leave it. We will go through several sets of lines with just that one plane, so it is not a luxury. If you crash often, well, that may be a different story.

That is still the longest line allowable (from grip to center of airplane - most people specify the lines by eyeley-to eyelet length, meaning 67 -67.5 is about the max). But that doesn't mean you have to use it. I use 63 foot lines on my airplane, mostly becaue it gives me better control feel. The lap times are faster than they would be at 68, but but my ability to put it where I want is better. Mr. Fancher, Mr. Fitzgerald, and I came up with this semi-independently.

> Line length is not
>an easy adjustment to fiddle
>with, as extensions are universally
>considered unhealthy.

I think it's almost trivially easy, since you can just meke up sets of different lengths and try them by merely switching.

>Rethinking, what lengths do you like
>for 35s, 40s, and up?
>Longer lines have a clear
>advantage in maneuvering room, and
>some associated loss. I have
>begun to doubt my judgment
>here, and think perhaps a
>Flite Streak would do better
>on 63 or so, even
>with a wimpy Fox 35.
>And maybe stretch the FP40
>profiles out to 65 or
>67. Too much line? Assume
>legal diameters.

The old rule of thumb was to use as short a lines as possible with the Fox. I think Bob Geiseke used 58 feet when he was winning with the it. For the others, just fiddle around to find the best combination of control precision and maneuvering room, and airspeed.

Well, I'll be darned! I could not have been more surprised at your answers. One of the things that all of us do (whether we admit it publicly or not) is "night fly" in our minds as we drift off to sleep.

The idea of longer lines seemed so inherently appealing in "night flying" I was ready to go long.

You guys don't seem to find a big advantage to longer lines, and I think I will back off that approach. Brett at 63' in a real competitive world just blew me away. I really thought one of the advantages of piped 61s was the ability to tow big 70' .018s.

Ted is also running 63, and I think David is on 64. The airplanes have no problem at all pulling 70 feet of line, it's just that the line whip and springiness (from both elastic extension, and from drape) add compliance to the system. Also, it's easier to hit 5 feet.

To confound you further, I also run .018's on piped 40s, and at the Team Trials (where I could run any line size I wanted). I prefer the control feel due to reduced stretch. This is a huge difference with .015 and .018.

Having said all that, I still suggest experimenting with line lengths on either side of what you are used to. 2-3 feet will be enough to really see the differences. Try the longer lines, and see whether you like them better. My opinion is far from universal- Bob Hunt and I had a discussion about this exact topic at the NATS and he has a diametrically opposed position. - he wants to run a super-light 40 airplane (mid 40's/660 sq inches/PA40) with .012 solids at max length.

Larry,

Here's a thought for you to process. If your airplane is thirty-five feet in front of you and flying at four seconds a lap (sounds too fast, doesn't it), how precisely do you think you could hit five feet every time? Now, if that same airplane was on 200 foot lines at 10 seconds a lap (sounds nice and slow doesn't it) how precisely do you think you could hit the magic five?

Two things at work here. First of all the longer the lines for a given lap time the FASTER the ship must be closing with the ground since airspeed MUST be higher to fly equal laps. Ergo, the closure rate is much faster regardless of how far away it is. Second, the closer an object is to you the easier it is to "place" it in any desired location relative to you. The farther away the smaller a given location becomes. That's why it's so much easier to hit a bulls eye at 10 feet than at 100. Flying stunt is akin to hitting moving bullseyes hundreds of times per flight. The easier you can make zeroing in on them the better.

Make any sense???

A lot of it has to do with the trim on the plane, but what Ted says is absolutely true. If you keep the same lap speeds, and you need to stay within a certain range in order to keep proper tension, then the longer the lines, the faster the plane. Or, if the plane's speed remains the same, then the shorter the lines, the faster the laps.

You not only need to maintain certain lap speeds to keep tension, you need to maintain certain air speeds for an airplane to fly well. Thus a plane flying on 60 foot lines and doing 4.7 second laps will be flying about the same speed as a plane doing 5.2 second laps on 65 foot lines. Here the closure speed to the ground will be the same, but you will have more space in which to place your maneuver. And less tension. For some that can be good, for others it can be bad. You need to fly on what works best for you and your airplane.

(I didn't know that you were at 63 feet, Ted. And David is at 64 feet. And Brett is back at 63 feet. Hmmm......)

When Noel Drindak handed his technical survey around at last year's pilot's meeting, Ted and I owned up to it (mine was 64 then). Only later did we find out Mr. Dave was also using somewhat shorter than normal lines.

Ted and I came to the same conclusion more-or-less independently, but mostly based on flying his Chizler on 58' .014 solids. Talk about perfect control feel - it was like having your fingers attached directly to the bellcrank.

Combine the solid-contact handle, the .018s vs. .015s, and the reduced length, and the control feel and thus the precision has gone up dramatically. These factors are VASTLY more imnportant the aerodynamic "numbers", wing loading, airfoil shapes, etc. that we end up spending all our time waxing poetic about.

The defining consideration in any of this subject is the airspeed at which the airplane performance is optimum. There are a ton of variables in this part of the equation alone but let's assume it is "XX MPH IAS (indicated airspeed or the speed at which the airplane "feels" it is passing through the air based on air density, etc...I said this was somewhat complicated, so stick with me!)

This airspeed is going to vary based on a number of factors the most important of which are probably wing loading and power loading (think in terms of "power TRAIN" loading including props etc...which once again indicates the complexity).

Once that "perfect" IAS is determined the solution to the problem can diverge in two different directions. Either #1; we can stretch out the lines to a length that produces a particular lap time if we think that is important (Brett and I don't particularly) as long as adequate tension is retained for positive control, or, #2; we can shorten the line length to bring the ship closer for the purposes we've discussed until such time as the lap/manevuer times become unacceptably quick for our personal preference/capabilities.

It is probably safe to state that lighter loaded ships can generally be flown positively at a slower IAS and can thus utilize shorter lines than can a similar ship that is heavier loaded. Thus on similar length lines my 62oz Final Edition with small flaps flies about a 10 of a second or so faster laps than does Bretts Infinity with roughly the same area but larger flaps and two tenths of a second or so faster than David's StarGazer which is very similar to the Final Edition but weighs about five or six ounces less.

My feeling is that David (if he is comfortable flying faster laps/maneuvers could likely reduce the pitch on his prop which in turn slows the IAS and reduce his line length even further to regain the lap times he prefers with the airplane even closer to him.

There is, of course, a finite limit to the efficacy of this trim approach. The airplanes are of a fixed size and eventually the available airspace gets too crowded to allow attractively sized maneuvers.

Brett's mention of the Chizler is particularly instructive in this regard. There is an almost unwritten bit of stunt folklore which avers that 5.5 seconds per lap is some sort of holy grail that optimizes our stunt devices. Like much of our cast in granite observations, this isn't very accurate.

The Chizler flies best on the 58' lines at 4.9 to 5.0 sec per lap which sounds sort of fast to those weaned on the aforementioned stuntlore. The thing that is interesting is that it seems much slower and more controllable in maneuvers than the "heavy iron" flying 5.5 sec/lap on max length lines. This is because the actual airspeed and thus the rate of closure with the ground is actually much more modest. Since it's slower and closer to you it is much easier to make the precise pullouts and maneuver sizes which are called for by the pattern.

Another aspect of the lap time/line length tradeoff is that even really fast isn't necessarily bad, as long as it's steady. The little Skyray, when flown on 58 foot lines, used to whip around at 4.4-4.5 second laps. But it was absurdly easy to fly, since the speed never changed. Abrupt speed changes, like from 4-2 break with a 6" pitch prop, made it very difficult to get into any sort of rythym. For whatever reason, I am particularly sensitive to this and pretty much can't just get used to it like the more naturally talented pilots like Ted, Bart, Bob Whitely, etc. Additionally, the control sensitivity changes a lot with speed, so making it constant really helps it to respond consistently.

I have since lengthened the lines on the Skyray first to 60, then 62, and got the laps down to about 4.7-4.8. But the steadiness is still there. The additional space helped overcome the relative lack of cornering.

Fascinating.

Some pretty high powered stunt people have chosen to share what they feel is an important means of improving the performance of anyone's stunter which doesn't require a degree in aerodynamics or two-cycle propulsion systems. Yet, the subject appears to have been unappealing to most who viewed it.

This is not a complaint, only an observation. Can anyone share an opinion on why the availiablity of information which to this point has been held fairly closely by several of the top flyers in the country has no appeal for others???

>Yet, the subject appears to
>have been unappealing to most
>who viewed it.

I went back an rated it a 10 myself, to see how many votes there were. One "10" vote ran it up to 7.4, which doesn't really add up, but does suggest that there was probably only one vote that made it a two.

Then I went back and hit 10 a bunch more times!

Brett --

Leonard only made one mistake in setting up this site that I can see. Ratings. They don't mean beans. Your rating of a thread, my rating of a thread, and anoyone else's rating of a thread are meaningless. Like most, I read stuff I like and pertains to what I am doing now. I respond to stuff that I might feel like a know a little something about. I ask way, way too many questions, and know that. I skip posts that don't pertain to what I am doing today. I post wrong answers, and learn from that. I ignore responses that don't fit my questions.

Ratings don't mean beans. But I have learned a bunch!

(Edit -- Although ratings mean nothing, it is sleazy to give a good rating to one of your own posts.)

Larry Fulwider

I'm confident there are lots of lurkers out there like me who just don't bother to rate discussions. You may rest assured that we ALL appreciate and savor threads in which the top guys are generous enough to take the time to contribute their wisdom. We are in awe! Please keep up the good work.

I truly appreciate the expert responses and have spent alot of time "qualifying" a certain group of responders as "knowing whereof they speak" so to say.

THe more technically correct and thorough the response, the better I like it.

I dont, however, very often at least, rate the threads. Lazy I guess. Perhaps its because I read virtually EVERY thread.

Dont sugar coat the details!

Thanks to all of the posters, but especially to the very experienced who freely share what many would consider to be "Competitive Advantage"

I'll second Gary's perspective. There are some real technical jewels here and they arent buried very deep in distracting junk.

I truly appreciate the expert responses and have spent alot of time "qualifying" a certain group of responders as "knowing whereof they speak" so to say.

THe more technically correct and thorough the response, the better I like it.

I dont, however, very often at least, rate the threads. Lazy I guess. Perhaps its because I read virtually EVERY thread.

Dont sugar coat the details!

Thanks to all of the posters, but especially to the very experienced who freely share what many would consider to be "Competitive Advantage"

Curt

Sorry Leonard and all....it did it again. Said it couldnt open the server. I backed out, came back and re-sent. It was there again.

I'll try to be more patient next time.

I guess that's why Brett is a rokit siuntyst and I'm still trying to light a fire by spinning a stick on a stick.

Point well taken and I shan't be led astray by meaningless rankings again.

I do not now of any other place where anyone can ask a question and get a responce from world class people. This entire post will go into my c/l goodies file. The infomation base here is great. Thanks guys.. Steve D.

Please do not be. As others have said so well, threads like this are especially appreciated. I very much enjoy the "How does a watch work?" types of posts. Your comments and those of Brett and Leonard would be so much less helpful if you simply said: "Well, I suggest using 63'9.178" lines on your Sodbuster 91." That might be helpful for someone who has such a beast, but it certainly would not be at all helpful to those of us who fly more modest craft.
So, please keep all the info that you have time for coming. But, I, like Larry, will not rate it. I will, however, enjoy and greatly appreciate it.