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[Motorman]

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[john e. holliday]

Think about it, wider spacing is like using a longer lever to lift something, but in the case of control line it gives more throw with little movement of handle which makes the plane more sensitive.   Depending on plane set up it works great of you want to do violent maneuvers.   The narrower spacing is used more for racing if plane is balanced right.  Really there is a happy medium between the handle spacing and the plane set up.  When I was racing in the early days I would set my planes up so you could almost fly them blind folded but yet I had enough movement in the system to get out of trouble if needed.

By the way it goes similar for the bell crank and control horn.  Way back then we had a big choice of bell cranks with Veco and Perfect,  you had either a 3 inch or 2 inch unless you made your own.

[Brett Buck]

Assuming the same control sensitivity and the same ratio from handle to flippers what is the effect of wide handle spacing compared to narrow line spacing? Would you get a  better feel one way or the other?

     It will respond more quickly with a wider spacing, and more slowly with a narrower spacing.

   To a limited extent, you can also play the CG position against the handle spacing to get the response you need. Each case is determined by the details, but, in general, CG far forward and handle wider (to get the same overall sensitivity) tends to be less sensitive around neutral and then gets progressively "faster" as the deflection increases. The CG far aft and handle narrower is the other way around, faster around neutral and less sensitive as the deflection gets larger.

   As an observation, over the years, people used to routinely have the overall sensitivity too high/fast. But recently, most people's airplanes I have flown were  far too slow, particularly around neutral (although I had a classic counter-example just last weekend).   This came of setting up the airplane however they did it, using whatever handle they had, and then adjusting the sensitivity only with the CG. Now, you can set the CG of the airplane to have it fly best and independently adjust the sensitivity at the handle.

    Modern airplanes (large tail voume) have a much larger tolerable range of CGs and you can make a huge difference in the way they fly by adjusting the handle and CG to get the type of response you want. You might think that you want it to be slow around neutral (which is the idea behind exponential controls, either the handle or bellcrank), but that makes it much harder to start and stop maneuvers smartly, and make the corners less controllable. Most of the very best airplane tend to be pretty sensitive around neutral and then slow down, make it much easier to delineate the difference between "turning" and "straight line" that is so critical.

   Older airplanes (almost all classic models and Nobler derivatives) can tolerate only a small range of CG positions  - too far forward and you don't have enough torque to turn it, and too far aft, and it is unstable. The range can be tiny at times, and whenever I go back and fly a Nobler, I am struck by how much the sensitivity changes from the beginning to the end of the flight due to the 4 ounces of fuel running out. 1/16"  or 1/4 ounce of nose weight makes a huge difference. It still happens on modern airplanes, but not nearly to the same degree, and of course, not at all with electrics.

     Brett

p.s. this is one of those things that people always want to claim "personal preference" or "my wrist is different" sorts of deals. Again, like most other items of similar nature (like the handle neutral), the range of usable sensitivities to be competitive is *very narrow* and your wrist (whoever) is *not* that much different from anyone else's. I have flown a large number of nationally-competitive and winning airplanes, and you would be amazed how close everyone who manages to compete at the highest levels are to each other. So I used the phrase "sensitivity you need" above, instead of "want", on purpose.

[Tim Wescott]

Assuming the same control sensitivity and the same ratio from handle to flippers what is the effect of wide handle spacing compared to narrow line spacing? Would you get a  better feel one way or the other?

I'm not sure what you mean by "the same control sensitivity and the same ratio from handle to flippers".  If you mean, for example, that you're going to increase the leadout spacing at the bellcrank and then increase the handle spacing to match, then I would expect that you'd get a more solid feel out of the control system (because you've reduced the effective springiness of the lines).  The plane might feel more responsive because of the reduced mechanical compliance.

However, you'd also have to make the handle bigger, and you'd have more bends in the leadout path.

Making the handle bigger would increase the moment of inertia of the handle.  When you see folks making those super-light carbon fiber handles, it's probably working because the moment of inertia of the handle is minimized.  Making a wider handle would first make the handle heavier, and then it would increase the moment of inertia.  That change may obviate any advantage gained by reducing the effective spring of the lines.

Making more bends in the leadout path may or may not cause problems with friction and springiness in the leadouts.

It would be an interesting experiment to make a plane with a 6" bellcrank and see if there's any improvement.

[Manuel Cortes]

Hi all.
I´m not a top pilot at all, but here are my two cents about that.
After flying several years with a comercial handle, and assist to two Spanish Nats (World Cup contests, with Belgium, Italian, French, German, Swiss fliers…..) I asked some of them to catch their handles and feel the controls. They were much more slow than mine!!!!!!
Tom Dixon confirmed that by post.....
Y began to experiment slowing the controls narrowing the lines space in the handle, and, after a few months, my brain (need to train the long but slow wrist movement)  was ready…… for sure the control sense was far better an the scores grew up inmediately.....

It worth a try.

Kind regards.

Manuel.

[Mark Mc]

. You might think that you want it to be slow around neutral (which is the idea behind exponential controls, either the handle or bellcrank), but that makes it much harder to start and stop maneuvers smartly, and make the corners less controllable. Most of the very best airplane tend to be pretty sensitive around neutral and then slow down, make it much easier to delineate the difference between "turning" and "straight line" that is so critical.

     Brett

p.s. this is one of those things that people always want to claim "personal preference" or "my wrist is different" sorts of deals. Again, like most other items of similar nature (like the handle neutral), the range of usable sensitivities to be competitive is *very narrow* and your wrist (whoever) is *not* that much different from anyone else's. I have flown a large number of nationally-competitive and winning airplanes, and you would be amazed how close everyone who manages to compete at the highest levels are to each other. So I used the phrase "sensitivity you need" above, instead of "want", on purpose.

I am sure you are right with respect to more experienced/natural/just plain better fliers.  But I'm a rank beginner compared to most here.  One of the greatest revelations was when I made an expo handle to Larry Renger's design.  Over-controlling when pulling out of loops or wing-overs has been the bane of my flying.   No matter how smooth I try to be in the pull out to level, I'd always balloon on the exit and find the plane porpoising before I got level flight.  When I went to the expo handle, I was able to exit much cleaner and with almost no PIO.  Amazed the hell out of me.  I'm sure as I get better that I will be able to overcome my over-controlling, but there is a great utility in the expo handles for someone like me.  One might call it "personal preference".  I call it a useful tool on the way to learning to fly better (if I ever find time to get out to the field).  Not trying to be disagreeable here, just adding another perspective.

Mark

[Jim Hoffman]

Hi Mark,

I use a Larry Renger Expo Handle on one of my airplanes for a specific reason.  I find it helps the intersection of the vertical 8

But...……...the effect of the Expo handle is very small compared to overhang and line spacing.

Jim Hoffman
 

[Tim Wescott]

I am sure you are right with respect to more experienced/natural/just plain better fliers.  But I'm a rank beginner compared to most here.  One of the greatest revelations was when I made an expo handle to Larry Renger's design.  Over-controlling when pulling out of loops or wing-overs has been the bane of my flying.   No matter how smooth I try to be in the pull out to level, I'd always balloon on the exit and find the plane porpoising before I got level flight.  When I went to the expo handle, I was able to exit much cleaner and with almost no PIO.  Amazed the hell out of me.  I'm sure as I get better that I will be able to overcome my over-controlling, but there is a great utility in the expo handles for someone like me.  One might call it "personal preference".  I call it a useful tool on the way to learning to fly better (if I ever find time to get out to the field).  Not trying to be disagreeable here, just adding another perspective.

Mark

Some time when we're both at Delta Park make me fly your plane -- it may be a trimming issue.

[Tim Wescott]

I guess I didn't explain it right. You make the controls in the plane too fast so you use a narrow handle spacing. Then you have another plane where you made the controls too slow so you use a wide handle spacing. Both planes have the same sensitivity and balance. The difference is one would give you pull closer to the center line of your arm.

That's the case that I was discussing.  I'm not sure what you mean by, or how you concluded that, "one would give you pull closer to the center line of your arm".

[Brett Buck]

I guess I didn't explain it right. You make the controls in the plane too fast so you use a narrow handle spacing. Then you have another plane where you made the controls too slow so you use a wide handle spacing. Both planes have the same sensitivity and balance. The difference is one would give you pull closer to the center line of your arm.

   I don't think I understand that one.

     Brett

[peabody]

One Nats I was aware that Bob Baron began with what I perceived as "standard" spacing...about 4" or so....as the week progressed and he flew more, he widened that spacing to something closer to 6"!
Then the wing folded and he flew a 1/2a

[Mark Mc]

Some time when we're both at Delta Park make me fly your plane -- it may be a trimming issue.

I'd be honored.  I have no doubt my trimming is terrible, but I really have no other reference to go by than what I read here, and the couple of people I've offered to let fly my planes to have a look see have declined.  Probably because they're afraid my trimming is so bad they'll crash and I'll blame them...

Mark

[Trostle]

One Nats I was aware that Bob Baron began with what I perceived as "standard" spacing...about 4" or so....as the week progressed and he flew more, he widened that spacing to something closer to 6"!
Then the wing folded and he flew a 1/2a

Nobody should ever doubt the ability of Bob Baron at the handle of one of his airplanes.  Having flown one of his airplanes and talking to others that have, I think the word is that we were "astonished" that he was able to fly as well as he did given the sensitivity in the way he trimmed.

He won the Nats in '96 with an early flight that everyone who witnessed that finals agreed was the best flight of the day.  He was by for the dominate flyer throughout the '81 Team Trials.

Keith

[Trostle]

(Clip)

However, you'd also have to make the handle bigger, and you'd have more bends in the leadout path.

(Clip)

Making more bends in the leadout path may or may not cause problems with friction and springiness in the leadouts.

It would be an interesting experiment to make a plane with a 6" bellcrank and see if there's any improvement.

Wow, increasing the handle spacing and its impact on the bending of the leadouts is something I never really considered.  A 2 inch increase in line spacing, (essentially 1inch increase for each line) will change the angle at the leadouts by a almost a whopping 5 arc sec or about 0.08 degree.  That essentially becomes a non-factor when considereing the line rake angle changes when flying around the circle in any kind of wind.

Or, if I did not understand your statement, I apologize.

Keith

[Brett Buck]

When you're in a loop you pull more on one line than the other right? If you have more handle spacing the pull is farther from the center of your arm so, you feel it more.

      You also feel it more if you increase the overhang (which you didn't ask about). Essentially, you move the rigid part of the handle further away, and you get more "self-centering" feel.

    It's my considered opinion that you *do not want* to have very much overhang, nor any other "artificial" centering forces. People think it makes them easy to fly level or come out of corner semi-automatically, but very rarely does this work out, and what frequently happens is that because the control loads go up, you have to engage more of your elbow and forearm to make it happen, and that creates more overshoot and more difficult cornering. Noseweight is a better approach if you don't have enough feel.

     The solution to flat bottoms and good tracking is NOT more noseweight or lots of overhang, or goofy control gadgets like the expo-crank or expo-handle, because this might make it want to go in straight lines OK, you won't be able to do anything else correctly - like have enough sensitivity around neutral to start and stop corners abruptly, which is what makes the corners look sharp and "correct".

    The solution is at the other end of the lines, the airplane, the design, trim, and power. I can only direct you (and whoever else is reading) to *known competitive designs* with *known competitive power systems*, and start to learn how.

      Brett

[Brett Buck]

Wow, increasing the handle spacing and its impact on the bending of the leadouts is something I never really considered.  A 2 inch increase in line spacing, (essentially 1inch increase for each line) will change the angle at the leadouts by a almost a whopping 5 arc sec or about 0.08 degree.  That essentially becomes a non-factor when considereing the line rake angle changes when flying around the circle in any kind of wind.

      I think he meant that you have to move the handle much less to get the same elevator deflection. From 4 to 6 reduces it by 50%, for example, so the angle between the handle and the line is similarly reduced.

     Brett

[Howard Rush]

Wow, increasing the handle spacing and its impact on the bending of the leadouts is something I never really considered.  A 2 inch increase in line spacing, (essentially 1inch increase for each line) will change the angle at the leadouts by a almost a whopping 5 arc sec or about 0.08 degree. 

I presume Tim meant that given a bigger bellcrank, you'd need a bigger handle. The bigger bellcrank would be what's causing the larger band angles at the leadout guides.  I'm contemplating a bigger bellcrank my own self, and I'm wondering if the increased leverage over control surface hinge moment would be worth the increased bend angles at the leadout guides.  Can one trust 19-strand leadouts?

I'm answering for Tim so he can spend his time making me new TUTs.

[Tim Wescott]

Wow, increasing the handle spacing and its impact on the bending of the leadouts is something I never really considered.  A 2 inch increase in line spacing, (essentially 1inch increase for each line) will change the angle at the leadouts by a almost a whopping 5 arc sec or about 0.08 degree.  That essentially becomes a non-factor when considereing the line rake angle changes when flying around the circle in any kind of wind.

Or, if I did not understand your statement, I apologize.

Keith

I was talking about the impact on the bend that's inside the wing.  In a typical setup with a 4" bellcrank you don't have room to move the front leadout hole forward, so you'll end up moving the pivot back an inch and the rear leadout hole backward by 2".  Given a 27" half-span that works out pretty close to 5 degrees more bend at the rear leadout.  I know there's folks who think the typical amount of bend at that leadout is already excessive.

I sincerely hope that the extra bend outside the wing is immaterial!

[Howard Rush]

Here's an example for a 5" bellcrank:

[Steve Helmick]

I thought MM was asking about what the functional result would be, given the same overall control ratio, from a narrow (say 2") to a wide (say 4") spacing at the handle.

This was discussed some years ago, perhaps on SSW, and the answer was precision in the ability to put your plane where you intend to put it with every input. Meaning that the wider handle spacing (with slower control system) should improve your tricks over the narrower handle spacing (with faster control system).

I asked the original question, and I believe Brett and/or Ted answered. Their answer confirmed my gut feeling that something was lost with a narrow handle spacing, but I didn't know exactly what.  Steve