Small spaceing at the handle

[Paul Taylor]

Can someone "explane" why you want small spaceing at the handle?

Thanks
Paul

[Bill Little]

When the lines get closer together, you have less leverage and less line movement in relation to the hand's movements.

This reduces the amount of control surface movement in relation to your hand movement.  "Slows down" the controls.

I guess it makes the plane "appear" to be less sensitive. 

[Bill Gruby]

Paul;

  Bill is right, theory is the closer the lines the less sensative to your movements. Have fun experimenting.

"Billy G"   

[Russell Shaffer]

Someone here said that the rule of thumb is to have the handle spacing the same as the bellcrank length.  I was flying my Streak with an old Hot Rock handle with about 5 inches spacing.  I made a handle with 3 inch space to match my bellcrank and the improvement in smoothness was amazing.  I should have done this years ago, but no one ever told me about it.  You can still get full control movement, just have to tilt the handle a little farther.  I've learned way more in a year on the forums than in all of the rest of my modeling time.

[Bill Gruby]

Russell;

  Yup, thats old school. Bellcrank width is where to start then adjust wider or narrower to suit your touch.

"Billy G"   

[Bill Little]

Try not to go less than the BC size, a whole new can of worms can be opened if that happens I've been told.  One caveat..... in the wind, the stick pressure builds and a narrow spacing makes it tough.

I, too, started off with the Standard E-Z Just.  Never used the "Hot Rock", and it's never been an issue with me it seems.  There are a few "Expert" flyers who still use an E-Z Just.  Having said that, it behooves *most* of us to have an adjustable handle to tailor to each planes idiosyncrasies.  I do.........

[Greg L Bahrman]

<Can someone "explane" why you want small spaceing at the handle?>

Paul,
It's not so much that you want small spacing at the handle. It's just an option for planes that are too sensitive to control input. Moving the lines closer together helps reduce the sensitivity and makes a twitchy plane easier to fly. On my last plane I moved the handle spacing wider because the controls seemed to be too slow and it made the plane more responsive. It's just another trimming tool that we can use if you have an adjustable handle. Another example of using the adjustable handle to your advantage is when my plane turned sharper inside corners than outside corners. By moving the up line closer to the center of the handle it reduced the sensitivity of the up line and now with equal hand movement up and down the plane responds equally in both directions. Very important when trying to put in a good pattern. Remember you don't necessarily want small spacing, it's just an option. I prefer wider spacings on my handles because I like to use 4 in. bellcranks. Another time I remember I was having trouble in my patterns with what is referred to as a pullout bump. It's when you pull out from a down maneuver like from a wingover and the pullout is not clean but has a little hop as you transition to level flight. By reducing the width of the lines on my handle by about 1/8 in. total I was able to reduce the sensitivity thus removing the little bump or hop at the pullout. That little hop is hated as it can reduce your scores and looks really dumb. Hope this gives you a better idea on how to use your handle to your advantage.

[Bill Little]

HI Paul,

Just to clarify.......  moving the lines closer together (in the vertical plane) reduces the control input in relation to the angular movements of your hand.  Moving them farther apart increases the control inputs and leverage.

Bob Baron had a handle line spacing of about a 7" spread on his '96 NATS winning Patternmaster. (no kidding)

I am guessing, but it seems that handle spacing on the "full blown" stunt ships is probably between 4"-4 1/2" on the Average.  Never measured them, but that's abuot what they "look" like.

A Flight Streak/Ringmaster style plane usually has less due to the plane's design factors. (short coupled, no flaps, less mass, etc.)

Bill <><

[Leo Mehl]

I have a 4" belcrank in my Grinder and i used a 4" spacing on my Handle. It actually made flying a little scary due to the trim on the plan. I changed the line spacing on the handle to 4 1/4" and then I didn't have to work so hard. When your handle spacing is to close it takes more wrist movement and sometime this makes th plane fly different than any plane you have so it can be over done. The handle is a good place to fine tune your flying. It is based a lot on the trim and balance of you plane. An interesting subject and good Question! Leo

[Randy Powell]

Something that should be said is that after you are in the ballpark, it's a matter of feel and style, too. Case in point: I built a Cobra for last year's VSC. Built it exactly according to plans with the 2 to 3 control hook ups and fairly short horn arms - just what was on the plans. If I built all my planes this way, I suspect I would have gotten used to it, but the controls were incredibly fast. Plane flew OK, but I ended up with line spacing at under 3 inches to make it smooth enough that I was comfortable flying it. My PA plane has very long horn arms and pushrod hookups and line spacing around 4.25 inches and I had a huge problem going back and forth between the Cobra and my PA plane. It just wasn't the type of controls that made me comfortable. You reach a point in narrowing the line spacing where you start to lose control feel. I was past that with the Cobra and really couldn't fly it very competitively. If I spent more time just flying it, I suspect I could have increased the spacing to the point were I got the control feel back and just gotten used to it, but it really wasn't what I wanted.

My new classic plane has exactly the same control setup (bellcrank and horns and lever arm spacing) as my PA plane and, surprise, surprise, it has the same (more or less) control feel. Makes it astounding easier to go back and forth between the two.

[Greg L Bahrman]

<My new classic plane has exactly the same control setup (bellcrank and horns and lever arm spacing) as my PA plane and, surprise, surprise, it has the same (more or less) control feel. Makes it astounding easier to go back and forth between the two.>

Yeah Randy,
I mentioned the same thing when there was a discussion on bellcranks. I prefer 4 in. mainly because of what you said. It makes it easier to transistion from one plane to another. If I use 4 in. in all my ships then the handle spacing is also very similar and they all respond roughly the same. Anyway it works for me....Grins

[Steve Helmick]

Lengthening the flap (or elevator horn, if no flaps) is a better solution than narrowing the handle spacing. Handle spacing is generally easier, or the only practical option. Making the control system ratios right to start with is the real solution. It's not that hard to predict how it'll work. Use a 4" BC, 4" handle spacing, 1" arm on BC to 1" flap horn, then 3/4" flap to 3/4" elevator horn, and you'll get 1:1 ratios from handle to elevator. Move your hand 10 deg. down and get 10 deg. down elevator, etc. Doodle the math, and figure it out. This is NOT to suggest that 1:1 is optimal, only as an example. It's not that hard to figure out, but maybe it needs to be done as an article in SN?  Steve

[Ted Fancher]

Paul,
Greg had it pretty much right but I'd say it in a different way.  Narrow isn't better.  Wide isn't better.  What's better is what is right for the pilot to allow him to fly his airplane to the best of his ability with handle movements that are comfortable and normal for him/her.

The handle shouldn't be adjusted to trim the airplane but, rather, to adapt the needs of a well trimmed airplane to the comfort level of the pilot.  I wrote a couple of series of articles back when I was the Model Aviation Stunt Columnist that are applicable to your question.  One was a multi part series on design and trim of stunt airplanes and the other was a two part discussion of handles, especially the art/skill of using the adjustments of modern handles to make the pilot happy with the airplane on the other end of the lines.  These should be available throught PAMPA PRODUCTS.

The combination of these articles should make it clear how the two halves of the pilot/airplane equation must balance for best performance.  At the most fundamental level the trim devices on the airplane (leadout, tip weight, CG adjustments, flap elevator ratios and alignment) are utilized to make the airplane "happy" and how, only after the airplane reaches that state, the adjustable handle is used to make the pilot "happy" with how the "happy" airplane responds to his natural inputs.

In other words, except in the grossest sort of "pre first flight" bench trimming the adjustable handle shouldn't be a huge factor in first flight analysis.  Yeah, you should know (and plan accordingly) how sensitive your on board control system will be and make a "wag" handle spacing for first flights accordingly.  this cannot, however, be simplified to just matching the bellcrank span to the handle spacing.  A more important clue is the difference between the length of the output arm on the bellcrank to the input arm on the flap (or elevator on a flapless ship) horn.  The shorter the input arm on the horn is in relation to the output arm on the bellcrank the more sensitive the on board system will be and vice versa.

The current trend that has resulted in narrower spacing than in days past is the use of larger tails and further aft CGs which result in airplanes that are more responsive with less control deflection.  The result is that pilots --in making themselves happy,have narrowed the spacing on the handle so that the handle inputs they are comfortable with will result in the airplane response they're looking for.

What is gradually happening is changes in the on board systems (generally longer control input arms) which have slowed the systems to the point that handle spacing can once again be widened to near what we used in the past.

The reason this is desireable has been addressed earlier here as well.  If the handle spacing gets too narrow the "feel" the pilot gets from control inputs is reduced and the pilot loses much of that "seat of the pants" feel for what the airplane is doing.  Further slowing the controls allows the handle spacing to be widened and the feel of the control deflections acts on that longer arm to provide more feedback to the pilot.

Ted

[Leo Mehl]

Ted, Good explanation, I think not to bad for a young guy. I think maybe you have done this a few times.

[Randy Powell]

Good expanation, Ted. Dat's why you da man.

>>Further slowing the controls allows the handle spacing to be widened and the feel of the control deflections acts on that longer arm to provide more feedback to the pilot.<<

As a result, it seems easier to be precise in your inputs. I noticed with my latest PA plane with this sort of control system, instead of just "flicking" through a corner based on timing, I can finally actually fly the thing through a corner with something approaching precision. That's been fun.

[Dean Pappas]

Hi All,
Let me add to what Ted says.
Narrowing the lines at the handle to get the desired sensitivity is better than flying too sensitive, but it is a band-aid rather than the solution to the problem.

The sensitivity should be reduced by either lengthening the flap horn or making the bellcrank longer. I like both.

Why is the narrow line spacing bad? The control effort to deflect the flaps and elevator in a corner can be as much as several hundred ounce-inches of torque for a heavy ship with large surfaces. Converting to inch-pounds, that's anywhere between 5 and 15 inch-pounds of torque. That torque is developed with a difference in line tension, between the up and down lines, across the length of the bellcrank. Aha! Now let's do the ugly math.

The math ain't ugly because it's difficult, it's ugly because it highlights a problem: let's pick the middle figure of 10 inch-pounds. With a four-inch crank, that means you need a 2-1/2 pound difference in tension between the lines. Now, 2-1/2 pounds could be maybe one quarter of the total line tension (guessing 10 lbs). That means that one line might have 3-3/4 lbs and the other 6-1/4. That's almost 2:1.

One line will sag, both due to aerodynamic drag and due to G loading in the corner, twice as much as the other! When you neutralize the handle, the tension will almost equalize and then the mass of the saggy line will have to accelerate "forward" to match the other. This unwanted "tail" to every large input means that the controls feel like they are laggy and spongy.

Ideally, we would run long bellcranks, longer flap horns, and wide spacings at the handle for best control fidelity. What's more, this problem gets worse with lighter airplanes!

later,
Dean Pappas

[Ted Fancher]

Hi All,
Let me add to what Ted says.
 What's more, this problem gets worse with lighter airplanes!

later,
Dean Pappas

Yes, it do, Dean.  An important point I'm glad you added. 

It goes hand in hand with Brett Buck's comments in a recent STUNT NEWS regarding the Netzeband wall on my Tucker Special to which we added eight ounces of lead (on the CG) and improved the handling characteristics an extraordinary amount.

Ted

[Bill Little]

Yes, it do, Dean.  An important point I'm glad you added. 

It goes hand in hand with Brett Buck's comments in a recent STUNT NEWS regarding the Netzeband wall on my Tucker Special to which we added eight ounces of lead (on the CG) and improved the handling characteristics an extraordinary amount.

Ted

Hi Ted,

Thanks!  I have always felt better with the lines at least 4" or so spacing..... I have no clue why!  But I can tell you that everything that you, Billy, Bob, Paul, Brett, and Randy have told me, I apply.  That means that I don;t really have to know about the whys and wherefores, just "who(s) to ask"!  That way, it works and I learn.........  In some ways it's great to be the "blind hog".  I just learn and it's a painless education!  Thanks to you and the rest of the great guys who are willing to help.  I kow a lot more now than I sometimes let on simply because I learned it all by listening to, and what, others who DO know tell me.  I have no desire to reinvent the wheel, I just want ot take a great ride on it! :lol:

[Ted Fancher]

Hi Ted,

Thanks!  I have always felt better with the lines at least 4" or so spacing..... I have no clue why!  But I can tell you that everything that you, Billy, Bob, Paul, Brett, and Randy have told me, I apply.  That means that I don;t really have to know about the whys and wherefores, just "who(s) to ask"!  That way, it works and I learn.........  In some ways it's great to be the "blind hog".  I just learn and it's a painless education!  Thanks to you and the rest of the great guys who are willing to help.  I kow a lot more now than I sometimes let on simply because I learned it all by listening to, and what, others who DO know tell me.  I have no desire to reinvent the wheel, I just want ot take a great ride on it! :lol:

Thanks, Bill.

FWIW, it's a long line progression in which I'm just a single link.  I try very hard to give appropriate recognition for the things I've learned from those smarter than myself and then passed on when the time seemed right (like this thread).  The Internet and STUNT NEWS have multiplied the effectiveness of information distribution by about a thousandfold.  We're all the better for the resources.

Ted