Uneven Turn, Inside vs Outside

[Kim Mortimore]

I've had a chance to fly several planes built by other people recently, and it's been a surprise to learn that matched turn rates inside vs outside (or anything approaching matched) are more the exception than the rule, at least among this group of planes, which included Oriental and Nobler ARFs, several profiles, ARF, kit, and scratch, a Boxcar Chief.  OK, so the BC has an excuse with the high wing. 

Some turn tighter inside, some outside.  The skill level of the builder seems not very closely correlated with the degree of similarity in turn rates.  Given that thrustline and stab incidence are not the most easily measured or adjusted parameters (I was told I need two, count 'em, two *%#@& incidence meters, I bought one, the needle was sticky, I returned it, and later read "an incidence meter can tell you what you have--assuming you're using it right--but not what you need)....

What's your experience?  Maybe I just had an unlucky sample group, or are balanced turn rates elusive for others as well?   

Thanks,
Kim Mortimore   

[Bill Little]

Kim, I think you are correct in your findings!  A whole lot of people do not notice, or trim out, unequal turn rates. 

But, it is imperative if you really want to fly a precise stunt pattern in today's event.

What is unusual is that sometimes a plane will turn better outside for me, and inside for you, or vice versa.  I was hold my hand in a way that with the physiology of my wrist joint, it was easier to give down than up!  All my planes turned harder outsides than insides.  That is almost the exact opposite of the problem tht most people have.

Ted Fancher, among other top flyers, advocates a vertical hand, not one which leans forward.  This seems to help with letting the hand move more equally forward and backward.  With the hand tilted forward, as the Tom Morris handle does, it is easier to move the tilt the hand "back" (Up) than it is to tilt it forward (down). 

Bill <><

[Wynn Robins]

unequal turn is caused by an assemetric control system. the standard straight horns (90degree to joiners) are the biggest contributer to this.  This fits the descriptions of the arfs you named above.

I have an aritcle I am putting together for the online magazine that explains how to set up a symmetrical control system. .....watch this space

[Bill Little]

unequal turn is caused by an assemetric control system. the standard straight horns (90degree to joiners) are the biggest contributer to this.  This fits the descriptions of the arfs you named above.

I have an aritcle I am putting together for the online magazine that explains how to set up a symmetrical control system. .....watch this space

Hi Wynn,

Yes, that is defintely one of, if not the biggest factor, in most cases.  Unfortunately, my last 6-8 planes have had the correct geometry horns to correct this.  I say "unfortunately" because my hand position, and the way my wrist pronates and supinates is a bigger factor, for me.  My fingers naturally can go to a parallel position with my forearm in the "forward stick" position.  Whereas, they can only hinge about 45* in the "Back stick" position.  Also, if the hand is in a tilted forward position, it naturally has less movement "down" than "up".  The wrist anatomy and hand position still plays a factor.  It is stil a somewhat individual factor.  It will almost certainly take some trimming on each plane to work the fine points out. 

But I totally agree, a correct geometry control system is extremely important!

I'm looking forward to your article!

Bill <><

[frank carlisle]

Bill are you a left hand flyer?

[phil c]

I don't know about you, but trimming the inside and outside turn rate is the third thing I do on a plane- first is warps, second is tipweight, then turns.  While it is possible to put in good flights with a plane that turns differently inside and outside, it is a pain.  It's especially bad if you fly more than one plane.  Keeping track of which one has sluggish down is no fun.

I haven't worried too much about up/down hand movement for 20 years.  Set the handle so the grip is vertical(ala' Ted and Brett) when the controls are at neutral, in level flight.  Learn to fly it that way.  Just being able to adjust the handle consistently knocks out about 50% of your session to session variation.  Setting things up this way also frees you from the one plane/one handle/one set of lines syndrome.  The exact amount of up and down you can give with your hand isn't too important because you should be following the plane with your arm(Ted again).  When you do that, you have many ways to get control input besides just tipping your wrist.  The top flyers use them all.

Subtle differences in handle geometry can make a big difference in control response.  Many handles attach the lines to a bar in front of the handle.  If this bar is adjusted so it is not parallel with the hand grip, the inside/outside response changes.  It only takes a few degrees to make a difference.  Adjusting the overhang and whether or not the bar is parallel is another last resort kind of trimming tool. 

[Charlie Pate]

 Guys!
 Are we missing something here?
 Yes! , handle bias can be an issue;but how bout when the bias is correct an the problem still exist?
 Control symmetry is a possible,but how bout when the horn angles to pushrod are correct and the problem still exists?
 The reason I bring this up is I am having this problem and it is definitely a turn problem.
 Outsides fine ; insides OK unless you get behind and cram in the input ; then the plane starts to turn and seems to slow and drop,then start to turn and drop till it finally gets around ,or you let up on the up some.
Balance : neutral to slightly tailheavy at rec. c.g.
Flaps to elev .neutral and 1:1 ratio.
Plane : Hemstrought PT19 ,Silver Foxx 40, 11-6 ew 48oz.
Lap times 5.4 60ft. lines E-E

[Shultzie]

After reading all these posts....about stunters that do not corner the same inside as outside give some really good insight, but still....AT LEAST WORTH CHECKING CAREFULLY FIRST AND FORE-MOST would be:

Uhhhh? Pretty basic but for this old koot....IS THE FLYING HANDLE SET CORRECTLY FOR EACH INDIVIUAL FLYER. It amazes me just how unique each flyer has adjusted their handles. 

It just may be me and my weird flying habits...but every time I have been offered a test ride on someones stunt model for the first time.
It only take mere-moments into the flight....(EVEN  ON NATS WINNING-WORLD CUP WINNING models) it doesn't take an expert to feel the difference between the way a model turns...or grooves in flight.
I would suspect that for the most part a MAJOR VARIABLE----it is the habitual way we like to set that handle.
In truth...how often has anyone of us....flown another person stunt model...and after that first flight was over, just wanted to re-adjust the handle to their own liking?
I WOULD BET...THAT THE MAJORITY OF FLYERS...WORLD CUP WINNERS OR NEWBEE ALIKE, after that first fright-test flight...would like to make changes.

For example....OUR PATTERN by its very nature...is filled with manouvers that demand more input to the handle than others and even models over the years have been designed with airfoils that are designed with those varible G-forces in mind. 
Was it Al Rabe the first (maybe not?) that did not use a symetrical airfoil...so as to enhance certain aspects of flight manouvers...or other model design variations that was made to help, enhance, induce certain forces such as gyro procession effects of over sized propellers with multi-blades-or props blades that even with pitch changes,etc.   Finally in the end,would effect the way the model turns or grooves in flight.

Most of us (me too) are kinda like bumbling'-bees...we know what we like (from habit) and soon learn to train our eye-to-mind-to-muscle contol and begin to feel comfortable with the weird way some of our models characteristics dictate the way we must have to fly, in order to perform accurate manouvers in flight.

BOTTOM LINE: YES! Sometimes (though rare..at least for me) have I ever picked up the handle of someone elses model.....and have felt absoultely comfortable and pleased with the way that indiviual model performs ON THAT VERY FIRST TEST FLIGHT!

BARE-BOTTOM LINE: I would highly recommend working with the handle adjustments- FIRST! Especially if the model appearence and accuracy in alignment etc...seem normal.  Only then would I start to begin the serious and often difficult or virtually impossible task of making that new model performance..up to your expectations.

(gads what drivil...see what to much McDonalds new ICE LATE...DOES TO MY LAME BRAIN?)

[Ward Van Duzer]

Had that problem too! (Why have I had so many of these? Just too old, I guess, been doin' this too long!)

For years I fought this on my Profile Force. The full flapped one! I had the handle adjustment so whacked out I couldn't take any more. So, after the plane got a little beat up after 8-9 years (Yea, I put in an a tree at Huntersville) I decided to do a little surgery. So, I cut a hole in the bottom of the wing under the bell crank and guess what? With the flaps and elevator in neutral, the bellcrank was off center by at least 15 degrees. Now how could I have done that? Good grief Charley Brown! Well, I was able to put a "Z" bend in the BC to flap horn pushrod to neutralize the BC and guess what?

Even Steven! (All those wasted years!!!)

[Charlie Pate]

Ya know Ward , I found through the years,that when the handle was off some , by the end of the flight,it didn,t feel as bad as at the beginning.( kinda like drinking cheap beer).
As for the bellcrank, I can check that easily, as it is a take apart airplane.
I believe that handle bias and or control asymmetry is not my problem , but its all worth a look

[Ted Fancher]

Ya know Ward , I found through the years,that when the handle was off some , by the end of the flight,it didn,t feel as bad as at the beginning.( kinda like drinking cheap beer).
As for the bellcrank, I can check that easily, as it is a take apart airplane.
I believe that handle bias and or control asymmetry is not my problem , but its all worth a look

Charlie,

Are your hinge lines sealed?

Ted

[Ted Fancher]

Have to disagree with my friend, Schultzie on this one.

I think that uneven turn rates inside versus outside should always be corrected by airplane trim (usually a tweak of the elevator versus flap neutrals although things such as unsealed hinge lines causing differences in lift produced inside versus outside can cause the problem as well).

A difference in inside versus outside turn when the neutral handle setting is "OK" with the pilot is most often an aerodynamic problem with the airplane itself and should be corrected there.

The exception is when the pilot is so so enamored of a "relaxed" handle position at neutral (tilted foreward vice vertical) that there is insufficient line deflection available in the down direction to displace the elevator to the angles required for outside turns.  IN other words, you run out of line length differential before you can make the airplane turn.

I've seen two examples of this from my own experience over the years, once with David Fitz' Dad Bill on a Dolphin and another time with a very good area flyer who shall go nameless because he has since corrected the problem ... to his, I might add, great benefit in terms of flight scores.

Ted

p.s. harkening back to the thread on narrow handle spacing, the running out of down control situation is exacerbated (made worse) the narrower the line  spacing at the handle.  Another real good argument for a vertical neutral.

[Wynn Robins]

Bill,

I agree with you that hand position plays a part in the turn rate, and it does, I still advocate that people use a symmetrical control throw system.

Say for example you can give FULL control throw both ways ( hand in your most comfortable position and handle set that way) then the controls should provide equal movements bth up and down.  If they are not set up this way, then the trimming of the handle etc could be endless to get the turning rates equal......

anyway......I will let the article talk to it a bit more...

W

[Shultzie]

Have to disagree with my friend, Schultzie on this one.

I think that uneven turn rates inside versus outside should always be corrected by airplane trim (usually a tweak of the elevator versus flap neutrals although things such as unsealed hinge lines causing differences in lift produced inside versus outside can cause the problem as well).

A difference in inside versus outside turn when the neutral handle setting is "OK" with the pilot is most often an aerodynamic problem with the airplane itself and should be corrected there.

The exception is when the pilot is so so enamored of a "relaxed" handle position at neutral (tilted foreward vice vertical) that there is insufficient line deflection available in the down direction to displace the elevator to the angles required for outside turns.  IN other words, you run out of line length differential before you can make the airplane turn.

I've seen two examples of this from my own experience over the years, once with David Fitz' Dad Bill on a Dolphin and another time with a very good area flyer who shall go nameless because he has since corrected the problem ... to his, I might add, great benefit in terms of flight scores.

Ted

p.s. harkening back to the thread on narrow handle spacing, the running out of down control situation is exacerbated (made worse) the narrower the line  spacing at the handle.  Another real good argument for a vertical neutral.

I think I understand what you are saying...but still boggles my britches...is why some models just seem to fly so beautifully both inside and out....beautiful level laps both inverted and right side up...and turn beautifully and respond with such love and friendship..
Speak of love and friendship...
Gads you were so kind many years ago....when you left that beautiful black beauty of a stunter hanger on Bob Emmett's hanger wall...to gloat over with such passion that one day we finally begged Bob to take it with him to the flying field...so we could test fly that drop dead black beauty. Bob was more than a bit nervous when Joe Dill, Bob Welch, me and finally Bob Emmett himself  took turns at the handle of that stunter of yours. Everyone agreed that day, that was perhaps one of the nicest tuned and flying stunters that we had ever had the pleasure to fly.
(Bob mentioned that he thought that you didn't have that high opinion of that model) That model felt so comfortable and friendly. It just seem to do exactly what you asked of it...an then some.
If I remember...that model also had the very first ST-46 up front. Maybe that played a major role in the way it handled...but I still think it boils down to careful attention to building with good alignment on both the airframe and control surfaces...and CG locations plus so many other things such as tip weight..leadout line rake..etc etc..
Good post Ted!
Thanks...Love those beautifully detailed and artzie models..ROSE THROWIN HUH? NO! JUST LOVE GREAT LOOKIN AND FLYING STUNT MODELS...THEY RULE!

[Ted Fancher]

Hi Don,

Not quite right about my feelings regarding that airlane (which I'd love to reprise for Classic ... but, alas it's only thirty one or two years old).  I didn't dislike it at all and felt very much like your description of it under calm air to ideal conditions.  It had a fatal fragility under high wind conditions that I felt disqualified it from serious consideration for all weather competitions.  First, the high aspect ratio made it more difficult to locate maneuvers precisely in windy conditions to minimize the acceleration that is a byproduct of high lift and low drag (a given with the roughly six to one aspect ratio).  Second, the tail was much too flexible and tended to twist under load reducing the turn rates in high winds.  All the surfaces were monokote covered if you recall, and although the wing and flaps were fine as they were sheeted foam, the stab and elevator were made ( built up) from very light wood and thus suffered disproportionately under those conditions.  If I were to build another (unlikely since Classic is now stymied at 1969 eligibility) I would sheet the tail for the required rigidity.

It is worth noting that the second version of that airplane was the original Citation that won the first ever Nats Concours d'elegance in 1977 and place third at that Nats.  It had the wing shortened by three full inches and the stab/elevator were double covered with silkspan to stiffent things up a bit.  It was a more consistent flyer although no better under ideal circumstances than the Black Bird.

Ted

p.s.  By the way, that black airplane benefitted greatly with sealed hingelines late in my association with it.  It got to Seattle via a Northwest Regionals back in the '70s or early '80s when I flew it and then left it with Bob Emmett.  I hadnt flown it in a number of years prior to that event and, after practicing with it a few times I decided to see if I couldn't eliminate the several degrees of up elevator at neutral flaps which had been required to get the turns balanced.  I had earlier done the sealed hingeline thing with my 1982 Nats winning Intimidation (but in the opposite direction) which had required a lot of down elevator with flaps neutral.

Both airplanes subsequently trimmed out with the flaps and elevators neutral at the same time after sealing the hinge lines.  The bottom line result with the black airplane was the pleasant and "neutral" response rate about which you were complimentary.

[Charlie Pate]

 Ted
 The hinge lines are NOTsealed.
  That will be my next move.
 Thanks for turning my head in an obvious direction(Bill Little just hollered " Keep twisting ").
 Strangely enough, I seal the lines on all my new planes .This is a rather old ship (built for VSC III)
 and just wasn,t done. As a big proponent of sealed hinge lines I certainly should be practicing what I preach.
 I will let you know how it turns out in a couple of weeks , as the weather has just gone ppppttttttttt!
 Thanks again.

[Ted Fancher]

Ted
 The hinge lines are NOTsealed.
  That will be my next move.
 Thanks for turning my head in an obvious direction(Bill Little just hollered " Keep twisting ").
 Strangely enough, I seal the lines on all my new planes .This is a rather old ship (built for VSC III)
 and just wasn,t done. As a big proponent of sealed hinge lines I certainly should be practicing what I preach.
 I will let you know how it turns out in a couple of weeks , as the weather has just gone ppppttttttttt!
 Thanks again.

lOOK FOREWARD TO THE RESULTS, CHARLIE

[Trostle]

There is one more thing to check besides all of the above discussion on control systems, handle position and handle adjustment.

This is going to sound a bit rediculous, but I chased a problem I had with an airplane that did not turn insides and outsides the same for several months.  I went to extremes on elevator trim relative to neutral flap position and changing to up or down thrust to the point that I was able to somewhat get the same response on inside and outside turns, but the airplane was oviously just wrong as it would then not groove and level flight was either noticeably nose high or low, (I forget the exact situation). 

Then, after another partiuclarly frustrating session, I checked the elevator alignment.  That is the alignment of the elevator trailing edges, left and right.  Now, I consider myself a fairly carefull builder, but those elevators were over 1/8" out of alignment.  I straightened that out, went back to neutral elevator trim with neutral flap and zero downthrust.  Instantly, the airplane flew like it was supposed to.  Insides and outsides turned the same and the airplane grooved.

I have seen this problem with models by some other builders.  So, it would not hurt just to check the left and right elevator alignment.

I cannot remember which elevator was low or high, or which problem I had with the different ability to turn insides and outside turns.  Nor can I explain why misaligned elevators would manifest themselves into this sort of problem, but they can and do.

Keith Trostle

[Dick Byron]

I decided to add just a little to what Keith said. The controls must be checked for alignment first. All things assumed to be good, if the aircraft turns inside or outside better, you will find a cure in the line bias. That is moving both lines up or down to change the turning radius. If insides are small and outsides are large, move both lines down. A little at a time will do. I have experimented greatly with this adjustment on the cable handles I sold. It absolutely works, but it is not a cure all. Go ahead and try it. Any handle that has adjustable line spacing will work but only a finite adjustment will give you what you are looking for.

[Bill Little]

Bill,

I agree with you that hand position plays a part in the turn rate, and it does, I still advocate that people use a symmetrical control throw system.

Say for example you can give FULL control throw both ways ( hand in your most comfortable position and handle set that way) then the controls should provide equal movements bth up and down.  If they are not set up this way, then the trimming of the handle etc could be endless to get the turning rates equal......

anyway......I will let the article talk to it a bit more...

W

What you're saying is exactly the same thing I am saying!  We are in agreement.  The controls do have to be geometrically symmetrical.  I wasn't meaning to say otherwise.  And like you say, if they are not, the trimming is very difficult. 

I *AM* looking forward to the article!

Take care, Buddy!
Bill <><

[Ted Fancher]

Uhhhh? Pretty basic but for this old koot....IS THE FLYING HANDLE SET CORRECTLY FOR EACH INDIVIUAL FLYER. It amazes me just how unique each flyer has adjusted their handles. 

You might be surprised, Don that David, Brett and I (and even Uncle Jimby now) can pretty much pick up each others airplanes and handles and fly them essentially right off the deck.  Pretty strict devotion to the vertical neutral location and trimming the airplanes to be correct (not trying to trim "airplane" problems with handle adjustments) makes them very, very similar in flying feel.  The only part of our set-up that people seem to have problems with is getting used to the vertical neutral if they've "grown up" in the biz using a relaxed neutral setting. 

As I've commented or at least intimated, the use of a "relaxed" neutral position introduces variables into the control system that are counterproductive.  After all the work we've gone to to make sure we have everything in the airplane set up symetrically and at 90 degree inputs and outputs to one another the first thing we do is introduce a driving lever (the handle) that is biased 15 or 20 degrees which isn't a lot different from mounting the bellcrank at 15 degrees from the horns axes.  Just doesn't make any sense if you think about it from a "physics" perspective.

I mentioned Uncle Jimby above and he's a good example of what can be "cured" in this respect.  I give him very high marks for making up his mind to "retrain" himself from a very unusual and "wrong" method of manipulating the handle to something more akin to Brett, where he simply rotates with the airplane, holds the handle toward the airplane and makes "up and down" motions to do the tricks.  I give him high marks for doing so ... and the judges have given  him noticably higher marks for what happens at the other end of the handle.

Worth noting that now Jimby can pretty much pick up one of our airplanes and fly it comfortably.

Ted

[Peter Nevai]

I dont know how anyones Else's wrist works, but I find that if I position my wrist at an angle approaching what approximately 90 degree from horizontal. The amount of motion available for up control; is only a fraction of what is available for down. Just can't bend the wrist back any further. Also as my fingers get gradually shorter from middle finger to pinky, just making a clenched fist as if grasping a handle, naturally put the hand into a pistol grip position. IE the part of the handle closest to the pinkie will be pulled closer to the body than the end of the handle closest to the fore finger. At least for my hands the only way to remedy this asymmetry is to relax the grip with the pinkie and ring finger. I for one would not feel comfortable flying a plane using only the finger tips of my hand. All I know is that when I build a model straight and with equal amounts of throw, I can adjust the handle to a comfortable position and not have any issues of feeling that the plane is turning better one direction or the other. But then again I am one of those who flys inverted with the hand held parallel to the ground, been doing it that way for 33 years now and still when I had issues with unequal turns it always turned out to be the airplane and not hand position. 

[Bill Little]

HI Ted, Again!

I sometimes can say what I want to say, and that can be a problem.  I think is too simple terms sometimes.  Coaching 14 to 18 year olds fro over thirty years now does that to you I guess........ 

Above, I mentioned the physiology of my wrist.  Many others probably have the same situation!  It's no effort for me to have my knuckles parallel to the ground with my forearm also parallel to the ground.   This makes it much easier for me to give a forward movement (down control in upright flight) than to give a "back stick" (or "up") control input.  For a while that really messed things up!  It meant that is was super easy to do outsides compared to insides.  Actually it was a case of too tight outsides compared to insides since we naturally want to apply the same amount of "effort" in each direction.

Does this make sense to you?? 

BTW:  two years ago I committed to a "vertical neutral".  It took a little getting use to at first.  Randy even caught me with my hand tilted ever so slightly "back" from vertical!  He had Aaron change my handle without telling me.  Now I "feel" the vertical and it is good.

Thanks
Bill <><

[Bill Little]

I dont know how anyones Else's wrist works, but I find that if I position my wrist at an angle approaching what approximately 90 degree from horizontal. The amount of motion available for up control; is only a fraction of what is available for down. Just can't bend the wrist back any further. Also as my fingers get gradually shorter from middle finger to pinky, just making a clenched fist as if grasping a handle, naturally put the hand into a pistol grip position. IE the part of the handle closest to the pinkie will be pulled closer to the body than the end of the handle closest to the fore finger. At least for my hands the only way to remedy this asymmetry is to relax the grip with the pinkie and ring finger. I for one would not feel comfortable flying a plane using only the finger tips of my hand. All I know is that when I build a model straight and with equal amounts of throw, I can adjust the handle to a comfortable position and not have any issues of feeling that the plane is turning better one direction or the other. But then again I am one of those who flys inverted with the hand held parallel to the ground, been doing it that way for 33 years now and still when I had issues with unequal turns it always turned out to be the airplane and not hand position. 

Hi Peter,

What "angle" is your arm?  Is it fairly extended or more bent at the elbow?
By bending the elbow, the hand comes to a much more natural vertical neutral position.  In a straight arm position, it is going to be at an angle where the hand "points forward" like holding a match pistol while shooting.

I have my elbow bent at about 20*.

Bill <><

[Peter Nevai]

(deleted)
Sorry, Peter, this just didn't sound right.  Maybe you didn't mean it that way, but it was pretty insulting to some of the peopple who have posted, and reported it to the Moderator.

Bill Little <><

[Shultzie]

PETER...PETER!!!
The reason just may be that YOU HAVE CALIBRATED EYEBALLS!!
Truthfully....after working as a professional windtunnel model maker, I can assure you that accurate measurements are critical for precise controlled test situations...but in truth you just may be one of those highly gifted folks....(that like musicians call----PERFECT PITCH!)

We had one amazingly model maker and model airplane addict. Don Archer  used to pride himself...with his calibrated eyeballs and could catch the slightest misalignment..even before we used any calibrated test instruments. All he would have to do is mearly walk by and notice even the slightest variations.
I have trouble not only hanging a picture on the wall straight but worse yet..never could judge distance...and got into trouble when trying to learn to fly full sized gliders or learning to fly with instruments. THANK GOD AND GARY LETSINGER...I GAVE UP THOSE LESSONS, ALMOST AS SOON AS THEY STARTED!
 I would often get YELLED COMMANDS from the Tow Plane..."straighten up man...you are pulling  us to the left.
 With that in mind Pete...Consider yourself HIGHY GIFTED...or just plain lucky! I truly wish I had that kind of talent. 

(here is a photo of Don Archer with one of his beautiful scale "Fly Baby's" that I sketched up for his retirement a long time ago.

[Kim Mortimore]

Had that problem too! (Why have I had so many of these? Just too old, I guess, been doin' this too long!)

For years I fought this on my Profile Force. The full flapped one! I had the handle adjustment so whacked out I couldn't take any more. So, after the plane got a little beat up after 8-9 years (Yea, I put in an a tree at Huntersville) I decided to do a little surgery. So, I cut a hole in the bottom of the wing under the bell crank and guess what? With the flaps and elevator in neutral, the bellcrank was off center by at least 15 degrees. Now how could I have done that? Good grief Charley Brown! Well, I was able to put a "Z" bend in the BC to flap horn pushrod to neutralize the BC and guess what?

Even Steven! (All those wasted years!!!)

Ward,
When you were having the problem, did you compare the maximum control surface deflection up vs. down?  It seems to me that the off-center bellcrank should result in different amounts of up and down.  The only exception I can see is if the horn has a corresponding and opposite bias, which would tend to neutralize the problem.  Hope this makes sense. 

Kim     

[minnesotamodeler]

Guys!
 Are we missing something here?
 Yes! , handle bias can be an issue;but how bout when the bias is correct an the problem still exist?
 Control symmetry is a possible,but how bout when the horn angles to pushrod are correct and the problem still exists?
 The reason I bring this up is I am having this problem and it is definitely a turn problem.
 Outsides fine ; insides OK unless you get behind and cram in the input ; then the plane starts to turn and seems to slow and drop,then start to turn and drop till it finally gets around ,or you let up on the up some.
Balance : neutral to slightly tailheavy at rec. c.g.
Flaps to elev .neutral and 1:1 ratio.
Plane : Hemstrought PT19 ,Silver Foxx 40, 11-6 ew 48oz.
Lap times 5.4 60ft. lines E-E

What you're describing is what combat fliers used to call "bucking" in a turn (maybe still do but I haven't flown combat in a lot of years)...it's a series of high-speed stalls, from trying to turn a plane tighter than the wing can handle.  If your plane is doing this in one direction but not the other,  maybe you should check your thrust line for "zero". 

--Ray

[M Spencer]

  Dragt co-efficient of Ballon tyres Vs spatted,

  Some people use square (cross section) tyres,

  Or spat thin racing tyres ?

[Dennis Adamisin]

Every thing said to now makes sense, but I want to go back to Kim's original thoughts when he posted and take a differrent tack.  He mentioned that several others airplanes felt unequal, I wonder if ALL the pilots noticed that about their own birds?

My "different tack" is that physically/subconsciously we all make adjustments for things like unequal turn and that when we get used to a new bird we are really dialing in our own adjusments.  Closest experience I can muster are these:

* One of my early V-tail stunters, the Swea Pea had equal span wings, fixed leadout position and no adjustable tip weight.  I suspect one of these was a little off because the line tension would vary in different parts of manuvers.  If I did not fly it for awhile then picked it up it felt like it ws falling out of the sky, yet with a few flights I was subconsciously making the corrections and not noticing any issues.  It felt easy to fly.

* I picked up an OLD airplane of mine that my Dad was using to test some engines.  My rememberance was that was one  of the BEST airplanes I had ever had, and it had the contest record to prove it.  Yet some 12 years later all I could think was "Gee, I must have been a VERY good or very stoopid!"

Thus one of my "rules" for trimming out a new bird has always been to do it deliberately.  Take care of the obvious things like leveling the wings and getting the engine to run the same upright and inverted, then sneak up on line rake and tip weight.  Next step is just to FLY the bird and over the course of several flying sessions in different conditions, learn what it can - and  cannot do - and try to fix what's broke!

I wonder if any/all of us would have noticed the same things as Kim, and would we have noticed if we flew each of the birds a dozen or so flights?

[Bill Little]

Hi Dennis,

I wouldn't argue your points at all.  I know that "talented pilots" (not talking about me here at all!) can pick up a handle and make the subconcious adjustments in moments.  A case in point is my PAMPA plane and Randy Smith.   My plane is fairly well trimmed, but not "exactly" as Randy wold have it, I'm sure!  He flew it for me after a contest and could have easily put in a 500+ point flight.  He just did a couple maneuvers first then flew the pattern!  There are several guys out there like Randy....they can pick up the handle, fly the plane and make you scratch your head........ Todd Lee picked up my Ares years ago at Myrtle Beach and flew the pattern including a square vertical 8 and square cloverleaf.  I had a LOT of difficulty geting that plane to do the regular square 8s! LOL!!

I never knew HOW to make a plane turn equally years ago.  Wings level, engine run, yes, but inside/outside, no.  I just had to fly it and make the adjustments.  At least now, we can all do the "tricks" it takes to help out this situation.  And I also think that what turns equally to me might not for someone else! 

Bill <><

[Dennis Adamisin]

Bill:
I remember seeing a story somewhere about an experiment where people were given special glasses that inverted everything they saw.  After their initial awkwardness the people were able to adapt to the stange new world presented to them - their brains adjusted to the new "reality" and they got along just fine.

I think flyers make a similar subconcious adjustment.  I COMLETELY agree with you that a bird that feels absolutely equal turning to you may not feel that way to me (or mine to you).  I am not sure that it is strictly a "talent" issue either.  I think that some folks (not me!) are simply "wired" differently - they can make these adjustments more quickly than the rest of us.

Like George Aldrich who could fly a stunt plane EITHER Clockwise or CCW!

[Ted Fancher]

Bill:
I remember seeing a story somewhere about an experiment where people were given special glasses that inverted everything they saw.  After their initial awkwardness the people were able to adapt to the stange new world presented to them - their brains adjusted to the new "reality" and they got along just fine.

I think flyers make a similar subconcious adjustment.  I COMLETELY agree with you that a bird that feels absolutely equal turning to you may not feel that way to me (or mine to you).  I am not sure that it is strictly a "talent" issue either.  I think that some folks (not me!) are simply "wired" differently - they can make these adjustments more quickly than the rest of us.

Like George Aldrich who could fly a stunt plane EITHER Clockwise or CCW!

Denny,

Quite apart from your very cogent posts ...

It's just terrific to see you on line and talking about stunt ships.  We've missed you, my man! 

All the best to you and the family.  Please pass on our love to Big Art and Betty.

Ted and Shareen Fancher

[Dennis Adamisin]

Hi Ted!
Just discovered this forum the other day - quite by accident and registered.  Am having a BLAST.  Dad's 80th Bday party is in a couple weeks - I'll pass the word.

Give Shareen a squeeze & tell her I said hi too!