Line adjustment at handle

[Leo Elder]

I'm wondering how you expert flyers arrive at the line spacing you use and also the force adjustment? Is it fly and adjust to your personal preference or is there some other procedure?

[Randy Cuberly]

For the most part experience with airplanes and control systems usually tells you where to start.  Most experts if not all have decided on a particular type of control set up and know approximately where the handle width will need to be.  However all airplanes, even those of the same type will usually be a little different so there are changes to be made during the trimming process to get a particular airplane to suit the individual.  It's difficult to be able to tell you where to start without knowing the airplane you're using and the control system linkage ratios etc.  Therefore it's going to be a search process when you fly.  A lot depends on the size and type of handle you use.  Most (certainly not all) expert stunt fliers use Hard Point handles of the Fancher type or something similar (No Cables).  Most like and use very light handles with overhang adjustment (but some just try to minimize that) as well as line spacing adjustment.  The neutral adjustment on these handles must be made by using an assortment of different size line clips to lengthen or shorten a line.

I hope this helps some.  It's not a process that can be explained by remote without  knowing what you are using.

There is a trimming chart around that was created many years ago by Paul Walker that details the trimming process and the handle adjustment is included in this process.  I used to have a copy of it on my computer but recently built a new computer and guess it got lost in the process of switching files from old to new.  Someone on Stunt Hanger will likely have a copy of it.

Randy Cuberly

[Brett Buck]

I'm wondering how you expert flyers arrive at the line spacing you use and also the force adjustment? Is it fly and adjust to your personal preference or is there some other procedure?

   For me, it's mostly feel. I generally run as little overhang as practically possible to minimize the "artificial" control loading - using more than the bare minimum removes the feel for the genuine force feedback. The rest of it is getting the desired feel through the corners by playing the CG and the handle spacing off against each other.   In the gross, the thinner the air the more spacing you need, but depending on other factors the CG can either want to go forward or aft. The latter I just noticed via experimentation in the last year or so, and the "forward" part might be counter-intuitive, but it is what it is.

  Too slow on the controls and the airplane will tend to "hop" at the ends of corners, and too fast and it will tend to come up short. That too can seem counter-intuitive but it's a function of how your brain's feedback system works. If you see it turn slower than you expect, you are inclined to apply more force but you will also be "late" and have much more tendency to overshoot. That used to be how everybody trimmed  - tons of noseweigh, tons of force feedback, but soft. You can still do that and more-or-less get away with it in most cases, but you will have a great deal of trouble trying to overcome it as you try to compete with the Paul Walkers/David Fitzgeralds of the world.

    Brett

[Mark Scarborough]

Not to add anything specific to the input you are recieiving, but Paul has reprised his flow chart and more in Stunt News. His column alone is worth joining Pampa,,

[Russell Shaffer]

I have been told that the rule of thumb is to space the lines at the bellcrank length.  3 inch bellcrank equals 3 inch handle spacing.  Then you fly once and adjust from there. 

[Tim Wescott]

No matter what, you've got to fly the thing to know the right spacing.  Your main goal in setting the initial spacing is just to not crash -- as long as you get that right, you can refine from there.

[FLOYD CARTER]

No matter what, you've got to fly the thing to know the right spacing.  Your main goal in setting the initial spacing is just to not crash -- as long as you get that right, you can refine from there.


I think Tim is correct.  It all depends on what you get used to, and what works best for you.  My planes tend to have "fast" controls, because that works best for me.  Others who have flown my planes with my handle, had trouble with over-controlling because they were used to a slower response.  You need to try different settings and control responses to see what is best.

Floyd

[Brett Buck]

I have been told that the rule of thumb is to space the lines at the bellcrank length.  3 inch bellcrank equals 3 inch handle spacing.  Then you fly once and adjust from there. 

  That's not particularly reliable, because the rest of the system (bellcrank flap pushrod arm and the flap and elevator horns) also matter.

   Brett

[Tim Wescott]

  That's not particularly reliable, because the rest of the system (bellcrank flap pushrod arm and the flap and elevator horns) also matter.

Possibly good enough to meet my "don't crash" criterion.

[Russell Shaffer]

Very true Brett, but I'm following Tim's "don't crash" philosophy.  A person has to start somewhere after all.

[Steve Helmick]

When setting up the controls in the plane, it's pretty much impossible to make them too slow.  You can always use a custom extra wide handle spacing to compensate for too slow. What really sucks is to setup the controls too fast, requiring a narrow spacing at the handle and reducing precision of pilot input. Under 3" pretty much sucks.  I'd like to end up with around 4" spacing, maybe even 5". But it depends on how the plane's control system is setup.

I gave Tim a plane that could have used a slower control system, but gave him the lines and handle spacing that worked well for me. I'd be curious to know if he narrowed the handle spacing, because I flew one of his planes and I could barely get it to turn at all. Obviously wrong! No, really, I guess it's just what Tim likes. Yuk!
  Steve

[Tim Wescott]

When setting up the controls in the plane, it's pretty much impossible to make them too slow.  You can always use a custom extra wide handle spacing to compensate for too slow. What really sucks is to setup the controls too fast, requiring a narrow spacing at the handle and reducing precision of pilot input. Under 3" pretty much sucks.  I'd like to end up with around 4" spacing, maybe even 5". But it depends on how the plane's control system is setup.

I gave Tim a plane that could have used a slower control system, but gave him the lines and handle spacing that worked well for me. I'd be curious to know if he narrowed the handle spacing, because I flew one of his planes and I could barely get it to turn at all. Obviously wrong! No, really, I guess it's just what Tim likes. Yuk!
  Steve

Yes, I narrowed it down, oh Mr. "you can't have a control system too slow -- oh, sorry about the bottom of your airplane, Tim".

[john e. holliday]

How did we ever get a plane to survive when I was really getting into it.  All 35 size planes had 3 inch Veco or Perfect bell crank.  Even my combat planes.   The 4 inch E-Z Just was for every type of flying except combat,  that is where the 5 inch E-Z Just came into play.   Now I use the Fancher type and the E-Z Just style the late Marvin Denny used to make and sell.  I do have numerous other handles that I use once in a while.

[goozgog]

  I've only been back to flying C/L for twelve years,  
so I have recent memories of how my line spacing
has evolved.
   Starting with Cardinals/ LA.46's, 4" bell cranks and
4" handle spacing, I felt that I would always miss the
ground. I had the C.G. at about 30% of the mean chord
where the plans showed it.
   This worked well for the first six seasons, but almost
every expert flier I met told me to close up the handle
spacing. I didn't listen and I made slow progress.

   With better Ro-Jett and P.A. powered planes,
( 4" crank, 1" horns set @ one to one) ,
Len Bourel finally got tough with me and
insisted that I try closing the handle down to 3".
Instant improvement!
  The most noticeable effect was that the planes
 would pull out of the bottom corners flat and straight.
No more "whoop". I had matured enough to really know
that the plane would make the turn.

  The next step was flying Brad Lepointe's stunter.
Combat guys use very little control movement but
with the C.G. far aft. This convinced me that moving
the C.G. is the better way to adjust control sensitivity.

  Currently I'm using 2-1/2" spacing with 4" cranks
and 1-1/4"flap to 1-1/8" elevator horns  in 660 sq/inch
planes.  It feels good!  

   Just my two cents worth but it was a solid
learning curve for me.

Cheers!  

[EddyR]

  A Couple of years ago I spent a entire day at a contest taking photos of how people fly today with modern equipment. One thing that was apparent to me and I never posted on here was how different we fly today than we did in the 1950-60's. Back then with fast controls and handles with cables we used a quick snap of the handle and back to level handle to do a turn. I mean a very very fast snap. If you do that today with the setups we have now you would never get around the corner. Also we didn't extend our arm as many do today. The planes were smaller and light and we held our hand up higher than most today do.
 A few weeks ago I had the chance to fly a friends Ares built from kit plans and it had super fast controls. I was stalling the plane for a good part of the flight. I forced myself to do quick little snaps and the plane stared to fly much better. The builder did not listen to Don and I and built it to the old plans setup.
 Today's setups are much better for precision flying.
EddyR

[Brett Buck]

Just to be clear, the overall control sensitivity should be set with *handle spacing*, and the airplane performance should be controlled with the CG. This is one of the more important discoveries of the modern era. When I am discussing CG shifts to control the load in the middle of the corners, that's a matter of a few grams of noseweight. The effect is to run the airplane at a marginally positive stability in level flight at lower control deflection VS going marginally unstable at higher control deflections/load factors. Make the airplane happy with the CG adjustment and make the pilot happy with handle adjustments. The difficulty is translating what you feel to what you need to do.

   The "good old days", you built the airplane, got whatever handle you had, usually wound up with a really fast system, and then piled in noseweight until it was about right. Then go burn 20 gallons of fuel. There are still people trying to do that, but you don't see them on Friday and Saturday much anymore. That's why I sometimes hesitate to send people off to read old magazine articles, because although there is a bunch of good information in them, you still see the ancient era techniques.

     Brett

[goozgog]

Hey Brett,
               Thanks for the clarification.

 I think I was coming to your conclusion
about minimum positive stability and minimum
control deflection but it's good to have it
confirmed.

Cheers!

[dirty dan]

 
Combat guys use very little control movement but
with the C.G. far aft. This convinced me that moving
the C.G. is the better way to adjust control sensitivity.

Don't know why you would make such a statement although I will admit that from outside the circle this might appear to be the case. Thought I once used slow controls on Combat models. Then I took a closer look at Norm McFadden's setup...

Dan

[Mark Scarborough]

 
Combat guys use very little control movement but
with the C.G. far aft. This convinced me that moving
the C.G. is the better way to adjust control sensitivity.

Don't know why you would make such a statement although I will admit that from outside the circle this might appear to be the case. Thought I once used slow controls on Combat models. Then I took a closer look at Norm McFadden's setup...

Dan

DAN,, what the heck,, you do still pop in here once in awhile,,
are you ready to dust off your models again yet?

[goozgog]

Hello Dan!   :-)
              I suppose that I was taking a risk suggesting
that ALL combat fliers use small control movements and
small deflections. I'm sure there are exceptions.
I do not fly combat and I don't presume to have any
profound knowledge about it.

However...
    The reason I said that is because I regularly attend
contests at The Beanfield. For those who don't know,
this is Brad Lepointe's contest site and it is a hot bed of
world class combat. The guys usually fight it out here
before attending the World Championships.
    Most of the planes are those Eastern European
combat wings that have a 2" crank with a 1/2" throw
and an inch + control horn on the elevator.  
Measuring the wrecks I have in my shop, this produces
small elevator deflections.
   Talking to Brad Lepointe, and flying his airplanes,
we discussed the merits of small deflections and aft C/G's
on Stunt planes. He's a very serious combat guy but
also flies Stunt.
   Finally, I had a look at my 60's vintage VooDoo kit
and Mr. Wooten says that it only needs 15 to 20 degrees
of deflection. I think I'm safe in saying that not many
stunt planes are set up with a maximum elevator deflection
of 15 degrees.

Dan, I would like to know why you would say
my observations are wrong.  I'd also like to hear
from some other combat people.

(I like pictures, so I'm attaching a picture.)

Cheers!

 
Combat guys use very little control movement but
with the C.G. far aft. This convinced me that moving
the C.G. is the better way to adjust control sensitivity.

Don't know why you would make such a statement although I will admit that from outside the circle this might appear to be the case. Thought I once used slow controls on Combat models. Then I took a closer look at Norm McFadden's setup...

Dan

[Leo Elder]

Gentlemen,

Thanks to all you who have replied. You have answered my question and more.

I flew stunt during the 80's and early 90's with a Barnstormer Fox 35 and Gieseke Nobler OS35s. I'm going to dust these planes off, flush the fuel tanks and try to get a respectable pattern back.

Leo

[Steve Helmick]

DAN,, what the heck,, you do still poop in here once in awhile,,

Fixed it for you, Mark! 

Regarding Mr. Goozgog's 2.5" handle spacing...would be much better off with shorter pushrod arm on B.C. or longer control horns (and a wider handle spacing) that would get back to the same overall control ratio. Your friend may have not explained the details, only that your controls were too fast. Of course, changing to a narrower handle would have been the quickest or most practical fix. Doesn't mean you should build the next one the same way.  Steve