Equal turn

Ok, I missed it somewhere.....
What is the best way to get equal outside and inside turn rates without an "adjustable" handle? Can it be done?
I don't think the guys in the '60s had that luxury, so what did they (y'all) do, or did they learn "to live with it"??
Thanks!
Bill

Moving back "up top" for a response.
Bill

Hi Bill:

I also have a problem with tighter outsides than insides. I'm not convinced its the control system and would like to hear a way to tell if its just my inputs to the handle or the rest of the system. I am using a Morris-type biased handle with bar. It is fully adjustable.

Perhaps I should remove some of the down bias (all) and see if the loops become equal.

The control horns are all custom made to have "bisecting angles" with the pushrods--equal up and down with similar bellcrank inputs.

FWIW

On a ship with flaps, if it turns tighter on the outsides, you should lengthen the elevator pushrod. This works. Of course you should check for any appreciable amount of downthrust first. I like to check for equal turn in the Horizontal 8 but for me, it really shows up in the Overhead 8.

This can be the old bugaboo for a lot of stunt ships. Moving one line up or down on the handle does not work. It only changes the bias on your hand or the pressure that you feel (making it harder to hold neutral). But:

We have to assume that you do not have any up thrust or down thrust. We have to assume that your wing and your stabilizer is level with the thrust line. We also have to assume that you are holding the "bar" on the handle perfectly vertical when your hand is at rest or the plane is flying neutral. If that bar is angled forward, for instance when the plane is flying at neutral, they you will have more "up" and less "down" for the same hand movement.

Sometimes we make these assumptions and they are not correct assumptions, so it would be good to check it. Make sure that all of the above are what we assume them to be. If nothing else, have someone look at the bar on the handle while you are flying level laps.

We also have to assume that the design is not "far out" (thrustline, wing, stab, within certain "limits". If any of these are spread too far away, it will mess things up).

Then we have to assume that flaps and elevators start at neutral with one another. We have to further assume that the belcrank is at neutral with the flaps are at neutral. If this one is off, then the rates are going to be different and we are kind of sunk unless we purposely angle that bar on the handle in the other directon to compensate.

Now, from here we can make slight adjustments. If the rest of the plane is in trim, how is the glide? If it drops like a rock, then the flap is up at elevator neutral or the elevator is up at flap neutral. I would try to get this as close to neutral as possible. After that, if it doesn't turn up as quickly as down, and assuming you don't have an adjustable pushrod, hold the flaps at neutral and bend the elevators up just slightly. See if that helps. If the problem is the other way around, bend them the other way. If you have a profile, you can sometimes put a small wedge under the elevator horn to tilt it one way or the other to make this adjustment.

Now, I have said all this without asking you how you hold your hand when at neutral. If you hold you hand with the elbow bent, then you hand should be vertical or nearly so. If you hold your hand outstretched with the elbow unbent, then you will probably have your hand leaning forward a bit at neutral. However you hold it, make sure you have an equal amount of movement with your hand in both directions. Some people blame the plane and it is really a problem in how we are holding the handle. And when all is said and done, everything checks out "perfect" but you stll have a problem with it turning faster one way than the other, you can purposely set the bar on the handle at an angle when you are flying level. Bias the bar forward when flying level for quicker up response, bias the bar backward when flying level for quicker down response. It is a "klutz" fix, but it will, indeed, help an otherwise unhelpable plane.

>Moving one line up or down on the handle does not work. It
>only changes the bias on your hand or the pressure that you
>feel (making it harder to hold neutral). But:
>
Leonard,

I know you have some very strong opinions about what bias can do and not do regarding the position of the line on the the handle. I have found that I can adjust to some degree the "feel" I have when I have an airplane that turns insides differently than outsides. It could well be that there are other problems with the controls and trim set-up. Also, biasing the one or both lines up or down on the handle to trim for similar inside and outside turning ability, response and feel could only be masking whatever these problems are, but it sometimes is a usefull trim adjustment for me.

I am not saying you are wrong, I am just saying that it works for me.

>Leonard,
>
>I know you have some very strong opinions about what bias
>can do and not do regarding the position of the line on the
>the handle. I have found that I can adjust to some degree
>the "feel" I have when I have an airplane that turns insides
>differently than outsides. It could well be that there are
>other problems with the controls and trim set-up. Also,
>biasing the one or both lines up or down on the handle to
>trim for similar inside and outside turning ability,
>response and feel could only be masking whatever these
>problems are, but it sometimes is a usefull trim adjustment
>for me.
>
>I am not saying you are wrong, I am just saying that it
>works for me.

I know we have talked about this before, but I never asked what handle you were using. I have a feeling it is a cable handle like what Doug was using. And I have a feeling that as you bias one side higher or lower, you also have to readjust for neutral. And because of the different feel, you relax your hand just a little in that direction, and, not even thinking about it, cant the bar just a little. And tilting the bar will change the rate of inside to outside.

If I am correct in the above, try the experiment with a handle such as Ted has. You do not have to adjust for neutral with these when you change spacing--even if it is just the spacing of one side or the other. Set it up for the way you like to fly. Then bias it slightly by raising one side or the other. I am sure you will find that it feels "funny", but that the rate of turn inside and outside does not change. If anything, it will be harder to turn in the direction that you are trying to improve.

Just a simple experiment. Try it and report back.

Bill,
First you have to check whether it is the model or you. The easiest way to find out is to do lazy eights line to line. In other words, apply full handle each way until the model is flying on one line and the other is slack. If they are still unequal, it's the model and no amount of handle tweaking will make any difference.
You can correct this base condition by simply limiting the movement in the direction that it turns tightest, but this won't solve the whole problem, particularly if there is a big difference.
Another approach is to offset the flaps so that you have more flap in the direction of the tighter turn. This will soften the turn while sharpening the wider turn by reducing the flap in that direction. If carried to excess, this will make the model fly nose up, or down, inverted.
Once you have the base condition sorted, you can refine the 'feel' by adjusting the handle.
You're right about the 50/60's, we just learned to fly the beast.
I've built a total of eight Noblers and they ALL turned tighter insides.

>Bill,
>First you have to check whether it is the model or you. The
>easiest way to find out is to do lazy eights line to line.
>In other words, apply full handle each way until the model
>is flying on one line and the other is slack. If they are
>still unequal, it's the model and no amount of handle
>tweaking will make any difference.

Dave, this would assume that you have an equal amount of travel in each direction. Although this would be a good practice, it is certainly not necessary, nor is it indicative of the rate of turn. I believe it is the amount of input that must be applied to each direction that is the concern here. We usually shoot for about 30 degrees of travel in each direction and try to get this fairly even. However we end up limiting this to less than 20 degrees with full handle movement, so the whole exercise would not prove much of anything unless there were perfect stops in each direction that were precisely equal.

>You can correct this base condition by simply limiting the
>movement in the direction that it turns tightest, but this
>won't solve the whole problem, particularly if there is a
>big difference.

If you are, indeed, hanging the plane on one line while turning (not a good practice under any condition) and if the plane has, say, 35 degrees of "up" and 25 degrees of "down", then limiting the up movement would at least equalize the maximum turn rate in both directions. It won't help the one direction that does not turn as quickly, however.

It seems to me that we need to attack the problem of why it turns tighter inside than outside, (or vise versa) rather than simply putting stops on the direction that it turns the tightest.

One thing I forgot to mention earlier, however, is to make sure that the pushrods are not flexing. This can limit the turn in one directon more than the other quicker than anything. I had one plane back in the 50's where the pushrod to the flap was flexing. It did not turn as tightly on the insides for this very reason until I cut into it and replaced the pushrod.

Virtually all times I had this trouble the "culprit" was the engine's incidence.

A 1/64" offset, positive or negative makes a BIG difference.

If the ship turns too well on the inside loops and not good at all at the outsides the first thing (after making sure that the commands are kosher) to try is to put a cat's hair under the posterior mounting screws, I mean between the engine and the mounts.

I've seen "miracles" happen by just doing this.

God bless you!

In Christ,

I got a huge improvement in the unequal turn business by changing from Tom's handles to Ted Fancher's. It was the slanted handle.

I have previously stated that the bar being vertical is the key to making a front-bar handle to give you equal turns. I have tried moving one anchor up or down to influence the turn, but haven't really noticed a change. I found that if I tried to set the handle bar verticle with the elevators or flaps in neutral (based on the verbal instructions of a helper), the model might still tend to groove too high or too low, and the opposite when inverted. So I took to just fiddling with it and adjust by trying to get a "good groove goin'" both upright and inverted. Seemed to work for me, but I still had the outsides a bit bigger than insides issue.

Well, when we had our Clinic, one Paul Walker picked up the handle, looked at the airplane, and said he couldn't possibly fly it with that much bias. I was amazed. But we wrenched on the (Tom Morris) handle, changed clips, etc., and PW consented to fly it. Soon, it was turning equal insides and outsides. For me. The airplane flew quite a bit different. I liked it, but needed to practise a bit with it to get used to the new feel. Sometimes Paul uses a Tom Morris handle. I don't think the issue is the angle in the handle. It's about getting the bar vertical when the flaps are in neutral. However, if you are flying with your hand up in front of your chest, a handle without the wrist angle may be the way to go. I am planning to make a bubble level clip onto the bar, but I'm not convinced that it will help unless I can also be certain the flaps (not elevator) are in neutral at the same time. Steve

Great information guys. I hav e changed arm position after clinic-ing and have my hand up closer to center chest with elbow bent now.

I really don't notice the issue on eights. just in the outside loops.

And it is not a situation where one is good and the other is terrible--perhaps a difference of 5 deg at the top of the loop.

It could be I'm just so relieved to be done with inverted, I just yank the thing into the loops!

All of the other factors are set well--engine at zero, controls equal and very linear, etc.

I guess I've heard enough to start adjusting the bias toward zero.

Now if it would just stop: a)blowing b)raining c)snowing d)sleeting e)all of the above, I could give this a try!

Thanks