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General control line discussion => Open Forum => Topic started by: John Fitzgerald on March 10, 2012, 01:46:57 PM
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I have recently started flying some with hard point handles, and have noticed the line tension seems better in maneuvers than with the cable types, and the model seems to respond more quickly to input. Is that wishful thinking or do others experience the same?
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I have recently started flying somewith hard point handles, and have noticed the line tension seems better in maneuvers than with the cable types, and the model seems to respond more quickly to input. Is that wishful thinking or do others experience the same?
Not the line tension, but the "responds more quickly" part is definitely what it does, and the big advantage they provide.
Brett
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This is really just a long-form 'what Brett said':
All control systems have some spring in them, which absorbs some of your desired control input. With a cable-type handle, there's extra springiness in the system from the handle cables, on top of any flexibility in the controls in the plane and the lines. Any time you move your hand, some of that hand motion gets absorbed in the springiness in the control system, and whatever is left over goes into moving the controls on the plane.
With a cable-style handle, the effective amount of springiness in the cable depends on the line tension: with lots of line tension the cables pivot cleanly at the handle and nearly all the handle motion goes into pulling on the lines, but with light line tension the cables will tend to bow smoothly, and more of the handle motion will be absorbed in the cables rather than getting applied to the lines.
So when line tension is good, your plane feels more responsive, and when line tension is bad it feels sluggish. I suspect that what you are perceiving as "better line tension" isn't the amount of pull that you have to exert on the handle, but the responsiveness of the airplane to your control input.
Because, in the end, the only way that your handle could change the actual line tension would be by magic, and that hasn't worked in the Northern Hemisphere for centuries.
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Photo?
Charles
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Photo?
Charles
Charles,
Search on "hard point". You will find lots of pictures in the threads.
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Maybe the line tension seems better because I have better control with the hard point when the tension is low.
With the cable types, it's important that the cables are very flexible, not stiff.
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Charles,
Search on "hard point". You will find lots of pictures in the threads.
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Maybe the line tension seems better because I have better control with the hard point when the tension is low.
One thing is that the feedback is also stronger, or at least more abrupt. You move the handle 10 degrees, it moves the control N degrees *right then*, meaning you also get the force required to deflect the controls *right then*. The flexibility of a cable handle tends to filter out the peaks of force required. Given that we are all using a lot of overhang (if measured from the rotation point of your wrist) anything that increases the force seems a lot like a line tension change.
Brett
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Based on my limited and very amateur experience, all I can tell you is:
Remember the first time you drove a car with power steering? Flying with a hard-point handle is similar.
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I think that it also has to do with what type of cable and how the ends are made off. I certainly don't dispute what Brett and Tim are stating here. I fly a hard point handle myself and I did a couple of back-to-back tests to convince myself of this fact. I did ask a similar question about leadouts because most of us use cables to the bellcrank. The question is.....if it makes this big difference on the handle, then why don't we use solid or "hard point" leadouts?? The leadouts are a lot longer that the cable through the handle.
I know all the stories about solid leadouts......noisy, don't go through narrow leadout guides easily etc., but it just seems a little strange that it makes a significant difference on one side only. One of our club members made some incredible control handles for a few years with precision milled parts and bird's-eye maple wood pieces etc. He used a 47-strand stainless steel cable that is quite thin especially to prevent any noticeable stretch. I used a much thicker cable for my in-flight adjustable handles and he said that this was why I could feel the slight stretch when I compared them to the hard-point handle. I also did not use any metal tubing to make off the ends either, so I reckon that the slight springyness I felt was due mainly to the slight "give" in the loops on the handle cable ends.
What could be happening also, is that the cable going through the handle, around corners etc. also adds up to a slight amount of give in the system, and maybe(?) that is why the leadouts don't seem to be a problem here. Just my opinion...........
Keith R
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What could be happening also, is that the cable going through the handle, around corners etc. also adds up to a slight amount of give in the system, and maybe(?) that is why the leadouts don't seem to be a problem here. Just my opinion...........
Of course. The linear "give" of the cable is negligible. It's the bending of the cable as it comes out of the handle and to a lesser extent the other curves it goes around. Heavier cable makes it worse in some cases.
Brett
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I dont understand the stretch, the line are so much thinner then the handle lines. I allways told that a chain is only as strong as the weakest link. The stretch would come from the lines before any thing else. ?????????
Steve
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I dont understand the stretch, the line are so much thinner then the handle lines. I allways told that a chain is only as strong as the weakest link. The stretch would come from the lines before any thing else. ?????????
As above. The cable doesn't stretch along its length to any consequential degree, but it does have to bend as you deflect it. That puts a curve into it and that curve is a function of the stiffness of the cable and the tension in the line.
Brett
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To me, A cable handle is like a BIG OLD Cadillac with power steering while the hard point is like a F-1 race car. Turn the wheel (handle) and it goes there now, no hesitation.
BIG Bear
RNMM/AMM
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Looks like the consensus is that the main difference is due to the degree of springiness in the cable handle's cables. That could be negated by using limp cord for the leads, which is what the (Russians?) attempted to do a couple of years ago. The cable handles are also not usually adjustable for spacing, and the hard points have spacing adjustments. Anyway, it seems that many fliers use a spacing comparable to the standard Hot Rock spacing on their hard point handles.
I tried to replace a cable on an old handle with a tightly braided nylon cord, but it tends to slip when put under strain in one direction or the other, and locking mechanisms cut into it when tightened sufficiently to hold it.
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The question is.....if it makes this big difference on the handle, then why don't we use solid or "hard point" leadouts?? The leadouts are a lot longer that the cable through the handle.
Keith R
But we do use 'hard point' lead outs, that is of course unless you wish to use a capstan or reel for a bell crank with the cable looping around it.
I don't like the naming convention of 'hard point' - it is simply a pivot.
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Looks like the consensus is that the main difference is due to the degree of springiness in the cable handle's cables. That could be negated by using limp cord for the leads, which is what the (Russians?) attempted to do a couple of years ago. The cable handles are also not usually adjustable for spacing, and the hard points have spacing adjustments. Anyway, it seems that many fliers use a spacing comparable to the standard Hot Rock spacing on their hard point handles.
The Baron handle is indeed quite adjustable, for spacing, overhang, bias, neutral, including inflight neutral tweaking. That or something like it was what most people used before the solid contact handle. The Ted handle is adjustable for all the same things, except for the inflight neutral.
I am adjusting the spacing on moderately frequent basis to adjust to conditions. For example at the 2011 NATS I went one hole out on each side, and also later loosened up the front screw and spread the sliders out as far as possible (which gave me another half-a-notch of spacing). Usually I need just the one notch each side, this year was a bit hotter than it had been and two holes was too much. I also tweak the neutral with some frequency over tiny ranges
Brett
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that is of course unless you wish to use a capstan or reel for a bell crank with the cable looping around it.
Common in the early-mid 80's, also popularized if not invented by Ted Fancher. It's shown on the Imitation plans, for example.
Brett
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Keep in mind also there is a built-in slack to the complete system -Line bowing from airspeed/line drag. With a control input one line attempts to go taught and the other bows out further for a brief sec. Same going back to neutral, especially with a cabled handle. i.e.- An EZ-Just with it's war-surplus suspension bridge cables.
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I made my last hard point handle with a slot in each of the L-pieces instead of the holes for spacing. I then made a cut in a small piece of aluminim and added the 1.5mm piece of household wire bent as per the picture, and it's held in the slot on the L-piece with a 3 mm hex bolt. This allows for finer adjustment than the holes.
Like most things in stunt, there are trade-offs with L-piece handles like adjusting line lengths for neutral adds variable overhang etc. Overall however, it's quite a nice handle to use.
Keith R
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..to say nothing of the powerful psychological advantage: self-fulfillment of an anticipated improvement in performance.
(I still love my old "hard-point" handle, it's a Lou Crane design!)
About the only improvement that remains is to cast it in carbon fiber. 8->
L.
"Gucci can put three stripes on a turd and sell it." -Robin Williams
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..to say nothing of the powerful psychological advantage: self-fulfillment of an anticipated improvement in performance.
Interesting you mention that. Ted gave me the second prototype to try, and I figured it wasn't going to do anything, and I just put it in my toolbox for about 3 months. Finally he bugged me about it, and I grudgingly said, "ok, I will humor him, then get back on track". Stunning immediate - and unexpected - improvement. I wasn't entirely convinced until about 3 more months, when I flew the other airplane with the old handle and the old .015 lines. Did a wingover at a demonstration and it was a 6" pullout "crowd pleaser" because I didn't "lead" the control inputs enough to compensate.
It is not a psychological effect, straightforward and obvious engineering analysis will get you the right answer. It did take me a while to understand what the mechanism of the cable handle compliance was, but once I did it made perfect sense.
Brett
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Brett, are you SURE you hadn't been practicing extra hard just prior to that?
(I'm just pulling your chain - if you did a full engineering analysis on it and all, I'm confident you are convinced.) Since 1986 I have owned a Lou Crane handle; although it has a slightly different shaped adjustable trapezoidal frame, but nevertheless IS a "hard point" handle - rigid frame and lines attached directly to fixed points - no cables. It never occurred to me to do a full engineering analysis on it, I just accepted the blessing!
L.
"I am not young enough to know everything." -Oscar Wilde
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Just to chime in here. I started out using Brodak handles with the bars in front, and after a day flying in the wind, I realized it was getting really difficult to get the airplane to turn. I went to a handle Windy gave us sometime ago. This was a cable handle with very short arms. The next day, I flew it and I noticed the power steering feel he was telling me about at Brodak's. I flew with those handles until sometime after the 2011 NATS, when the cable in the handle broke in my Trivial Pursuit and the plane pancaked inverted. Here is the thread that convinced me to go to a Ted Fancher handle:
http://stunthanger.com/smf/index.php?topic=22798.0
When we got out to the team trials, Dave Fitzgerald and Brett Buck gave me one of Ted Fancher's handles and a new one to put together. I put the handle on my grandfather's P-40 and immediately fell in love with it. It was so much easier to fly the airplane and it was also easier to fly it at a more precise level.
When we got back from the team trials, I put the handle on my Oriental Plus, which I had been having trim problems with. After flying one flight with Windy's handle and having problems locating my bottoms, and popping up when they were right, I put Ted's handle on. Immediately, it was a lot easier to fly, and get the same responses every time I hit for a corner. My bottoms also went right back to the 5ft level and now I am sold on it. We flew today for the first time this year, and with the same handle on my Oriental Plus, besides being a little rusty, it was as if I only stopped flying for a couple weeks. Honestly, I think a lot of that reason has to do with the consistancy in the handle (and also having the plane in good trim).
Just my 2-cents. I will not use another type of handle for as long as I live!
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Wish I had an opinion here based on empirical evidence - unfort I dont..
Started using a Hard point handle in 1990. Brian Eather made a his own hard point handle for sale I started using that and havent used anything since. Certianly from those ive spoken too, cabled handles dont perform anywhere near as good.
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Here is my latest handle effort. I think it's a pretty good approximation of the "Ted" handle.
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That's a nice looking handle, John!
Bill
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Might a "Ted" Handle by any other name fly as sweet?
Just wondering. It seems to me that once basic geometry and relative position of the human hand are established, and the connection points for the flying wires are "fixed", then we are reduced to personal preferences on the grip. And the most enduring grip shape (including that favored by the Ted Handle) seems to be the one featured on the venerable old EZ-Just (not a hard point handle).
Whichever grip is favored by an individual, if the connection point geometry with respect to the flier's hand is identical, wouldn't the handles essentially be equivalent?
Might it be least theoretically possible to somehow merge the designs of the hand made Ted Handle with the elegant Maikis Handle (also not a hard point design) and say, the molded Brad Walker Handle (Brodak Rock Crusher)?
;->
L.
"In Syria, once, at the head-waters of the Jordan, a camel took charge of my overcoat while the tents were being pitched, and examined it with a critical eye, all over, with as much interest as if he had an idea of getting one made like it; and then, after he was done figuring on it as an article of apparel, he began to contemplate it as an article of diet. He put his foot on it, and lifted one of the sleeves out with his teeth, and chewed and chewed at it, gradually taking it in, and all the while opening and closing his eyes in a kind of religious ecstasy, as if he had never tasted anything as good as an overcoat before, in his life. Then he smacked his lips once or twice, and reached after the other sleeve. Next he tried the velvet collar, and smiled a smile of such contentment that it was plain to see that he regarded that as the daintiest thing about an overcoat. The tails went next, along with some percussion caps and cough candy, and some fig-paste from Constantinople. And then my newspaper correspondence dropped out, and he took a chance in that--manuscript letters written for the home papers. But he was treading on dangerous ground, now. He began to come across solid wisdom in those documents that was rather weighty on his stomach; and occasionally he would take a joke that would shake him up till it loosened his teeth; it was getting to be perilous times with him, but he held his grip with good courage and hopefully, till at last he began to stumble on statements that not even a camel could swallow with impunity. He began to gag and gasp, and his eyes to stand out, and his forelegs to spread, and in about a quarter of a minute he fell over as stiff as a carpenter's work-bench, and died a death of indescribable agony. I went and pulled the manuscript out of his mouth, and found that the sensitive creature had choked to death on one of the mildest and gentlest statements of fact that I ever laid before a trusting public." -Mark Twain, Roughing It
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Thanks, Larry C. for the comments!
The idea I had when I laid out the handle Larry uses included some currently politically incorrect thoughts. As I learned to fly CL in the 1950's, I was more comfortable with a pistol-grip hand attitude for Neutral. The grip raking outward toward the top...
This is a no-no nowadays, I understand. I also notice that the fliers who do so well with the grip axis vertical, and parallel to the line from "hard-point" to "hard-point" also raise their forearms as if sighting a pistol at the model.
---the natural rake I was comfortable with when the handle is about bottom rib high is still present with the "modern" pistol-aiming posture. It is done by the wrist, not the handle. This applies a considerable pull against your flexed elbow, no?
On Larry's handle, the hard-points are on a separate frame, pivoted at the top, and adjusted (safely, in flight, too, if you're moderately careful) by a jack-screw to the bottom of the 'line clips frame.'
Ideally, and often in practice, the line connections are in line vertically, while the grip can be adjusted for comfort however high or low you wish to hold on.
Main problem with my too-adjustable handle is weight. (Sensitivity, i.e., line separation at the handle; Bias, i.e., shifting the same line separation higher or lower on the grip, and neutral (minor adjustments by moving the jackscrew - which has a wing nut to lock the setting and a common nut the other side of the frame to reach the setting) are all possible in-flight.
Such a handle could best serve as a set-up lab to find the combination for a particular model and line length. With those key dimensions found, a lighter handle - without ALL the adjustments - can be made.
Think I had a photo of my own "Lou Crane" handle on here a few years back, or possibly on another site.