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Update:Cannot get wings to stop rocking!!
Hi all,
I have a BME Yak-54 with a DA-50cc, 22x10 prop. My problem is whenever I attempt to Hover from a Harrier the wings will start rocking from side to side violently, so I keep fighting them with no luck. What coud be my problem? Too small diameter prop? To much/too little throw on elevator/ail? too nose heavy? Any help would be much appreciated. Thanks, David |
RE: Cannot get wings to stop rocking!!
There are several things that could be getting in the way, up to and including the design of the tail. Moving away from that let's look at a few things. Everything below assumes that all the basic trimming out work has been done over the course of a whole bunch of flights. Things like balance, engine offset, up and down line trimming, etc. Going from harrier to hover requires a quick pull of max elevator, correct rudder input to offset torque and P-factor, and a good blast on the throttle to pull the nose around and push the tail down. Think about wing and tail position when you hit the throttle and you may find the problem. Here's some others.
Consider a c/g that's a little too far forward. Wing weight imbalance. You need to balance both statically and aerodynamically between the wing halves. Trim differences between ailerons and or elevator halves. Wrong type of prop. Operator unknowingly holding a small amount of aileron. This is a BIG one. Rudder trim or offset. Incorrect rudder input by operator. |
RE: Cannot get wings to stop rocking!!
Everything he said, plus all planes have their "sweet spot" aingle-of-attack, which can sometimes be greater than 45 gegrees, so it could be elevator throw or just a throttle/elevator management issue as well.
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RE: Cannot get wings to stop rocking!!
Going back over the original post I have a thought that the prop is part of the problem with a 10 inch pitch. My opinion is that an 8 inch pitch would be better.
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RE: Cannot get wings to stop rocking!!
Here's something else to try: add a little more expo to your rudder in 3D mode. Awhile back I discovered, by accident, that sometimes I could hover/TR better in normal mode than 3D. What it turned out to be was, I was overcontrolling the rudder and then having to chase it. Once I reduced the effective rudder sesitivity at mid stick, I was able to let things settle down. Once I got confident at these moves it didn't matter, because I could anticipate what was going to happen.
Have you ever noticed how in a nice harrier, when you raise the nose but don't add power the airplane descends, in an elevator? Try entering your hover in the same way. Establish a nice smooth harrier, then pull the nose up. Let the nose begin to smoothly pitch up and then smoothly add power to counter the descent. You'll find yourself in a nice, controlled, stable hover. If you come in with the power too soon, the airplane will begin to climb and you'll have to throttle back to maintain altitude. By waiting a bit, and I mean just enough to let the nose start to come up, you will be carrying a bit of power into that hover, which will give you more control (moving air over surfaces) and make the airplane more stable. With a little practice you can make the whole thing look like its happening in slow motion. When entering your hover from harrier in this way, you'll find there is less flopping around to correct for. Hope this helps! Dave |
RE: Cannot get wings to stop rocking!!
Dave, I typically enter the Hover the exact way as you describe. I simply transition from a Harrer to a Hover. Problem is, during the Harrier my wings will not stop rocking. AT this time, no aileron nor rudder input on my behalf, just throttle and elevator. I only correct when the rocking takes the model to a dangerous position requiring immediate correction. Once the model is pointing up, the rocking stops and it hangs, but I have very hard time positioning the model on the runway centerline becasue of the non-stop movement of the wings. That is, I cannot control the Harrier laterally.
I'm thinking along the lines of prop size. I will try with a 23x8 or 24x8. |
RE: Cannot get wings to stop rocking!!
Ah, I get it. So the problem is with harrier wing rock which is messing with your transition to hover. I would check your lateral balance and make sure its on. Then make sure all your surfaces are even. Bottom line, though, wing rock in harrier can be controlled. You just have to really stay ahead of it, correcting with the ailerons this instant the wings start to roll. The quick, little correctings required soon become second nature, and so fast nobody really sees you correct or the wings rock. learned to do it in G2, which I was told was a great way to learn because if you could harrier in that program, a real model would be a piece of cake. Anyway, its something to practice. Try just getting into your harrier with the plan of making one or two corrections and then flying out. Do stay in it until it becomes a mess. You'll master this quickly and then begin to lengthen the time you can stay in harrier. In time, you'll develop a feel for it in straight lines and turns.
best of luck, dave |
RE: Cannot get wings to stop rocking!!
The speed with which you make the transition has a large impact as well. To slow a transition from the somewhat horizontal to vertical and the remaining lift the wings are generating becomes an issue. A fast transition passes through that transitional lift period quickly enough so the wings do not have time to make an impact. An item of note is that the smaller aerobats are much more susceptable to this.
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RE: Cannot get wings to stop rocking!!
excellent point.
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RE: Cannot get wings to stop rocking!!
Silversurfer is talking about that most dangerous of times, the transition from flying "on the wing" to true high alpha, 3D. That's when you can really get into trouble and the need for a fast transition, as he says is very real. I often use a wall to get through it as quickly as possible. Once you're in a true, high alpha harrier, the wing really isn't lifting much. And once you can control the rock the transition from harrier to hover can be wonderfully slow. I have a video I shot jasut recently of this very thing using a little slimer I designed. But I don't know how to post it and provide the link. Its not much of a video, I'd actually be embarassed to show it. But the point is from a stable harrier with the nose up about 45 degrees, I slowly increase the angle of attack until I'm in a hover and then a torque roll. If I couldn't have controlled the rock, it would have been a mess......
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RE: Cannot get wings to stop rocking!!
Its a YAK. Yaks typically do not have significant issues with wingrock, as a matter of fact they are probably the most stable 3D platform there is, IMO. I have had Edges, Extra and Ultimates but have not owned a Yak, however I have flown my friends misc variations. The Yaks to me are as stable as you can get.
I would check and make sure that your lateral balance is good and form there its just a matter of sticktime. The plane should basically be trimmed out for normal flight and coupling issues that could not be corrected by setup should probably be mixed out. Yes, coupling effects the plane in every plane, not just on knife edge. SO the mixes will subtly correct some problems you are having transitioning from harrier to hover. My bet is that you are behind the airplane a little. All planes wingrock some, but you cannot tell when a pilot that has mastered the harrier is flying because he/she is subconsciously correcting before the problem ever starts. If you are looking at his sticks, the corrections are so small that you cannot see it usually. If you ever get up really close to a "pro" 3D pilot, you will be amazed at how little the surfaces move when they settle into a harrier or hover. It looks like the plane is just hanging there motionless, and it is, but that is because the corrections are way ahead and therefore they are VERY subtle. I have actually had a pro fly my Extra and although I wrestle with it some, in his hands it looked to be an absolutely perfect and stable plane. It would hover motionlessly inches above the grass like it was hung from a string. Practice makes perfect guys. Think of it like riding a bicycle. You are CONTSTANTLY making tiny corrections to keep the bicycle upright without even thinking about it. When you 1st start you either over correct, or do not correct soon enough and the bicycle is all over the place. Eventually your brain figures it out and you ride the bike without ever realizing you are correcting, much less seeing visible corrections. In time you will just do it. You will harrier and hover the same way.. Just keep doing it and eventually it will be second nature. |
RE: Cannot get wings to stop rocking!!
Mike,
didi you read my post? That's exactly what I said..... |
RE: Cannot get wings to stop rocking!!
Yep, just reaffirming your postion.[8D]
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RE: Cannot get wings to stop rocking!!
cool! Safety in numbers:D
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RE: Cannot get wings to stop rocking!!
ORIGINAL: FalconWings ...during the Harrier my wings will not stop rocking. AT this time, no aileron nor rudder input on my behalf, just throttle and elevator. |
RE: Cannot get wings to stop rocking!!
You have a pretty good point with the foamies. They always seem to just hang there and pivot with the wind some.
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RE: Cannot get wings to stop rocking!!
Well I don't get it guys. I've been flying 3D for a while. My last model was a H9 27% Cap and it never rocked the wings like my Yak is doing, and is a Cap!! As a matter of fact, that Cap was very easy to Harrier and move around the runway, inches from the ground. I purchased the Yak thinking that it would be even easier with it.
I don't think correcting is going to do it, the rocking is too violent and if it was controllable I think I would have handled it by now. My Cap rocked the wing very little and yes it was totally predictable. Lateral balance is not likely either. The airplane is pretty much "trim less". Perfect uplines, perfect downlines, very little trim required when inverted, and very explosive on high rates. I can Flatspin this sucker without loosing any altitude. I have mixes for Knife Edge and Idle to 1% downtrim. No coupling issues so far. Rolls are as axial as could be. Could anyone tell me if my prop size seems right? The model is 30% scale, DA50, BME 22x10. My gutt tells me to move to a 23x8, or a 24x8. I'm thinking I may not have enough prop wash over the ailerons. Did I mention that the wings will rock side to side? Not just left or right. Thanks for your help guys, keep it coming. |
RE: Cannot get wings to stop rocking!!
ORIGINAL: Silversurfer Wrong type of prop. |
RE: Cannot get wings to stop rocking!!
There is one thing that you might be overlooking.
weight I have had a flown a few planes of the same design where one was pretty heavy and it had a wing rock something fierce while the other was smooth as silk. |
RE: Cannot get wings to stop rocking!!
Falconwings,
It seems to me you have a handle on all the elements of this, and that you have learned to control wing rock in other planes. i bought this little slimer, a Great Planes UCD that rocked rediculously. I never could get it right. I think trying the bigger prop would be a good bet. You've got me stumped.... |
RE: Cannot get wings to stop rocking!!
ORIGINAL: AeroDave Falconwings, It seems to me you have a handle on all the elements of this, and that you have learned to control wing rock in other planes. I bought this little slimer, a Great Planes UCD that rocked rediculously. I never could get it right. I think trying the bigger prop would be a good bet. You've got me stumped.... I appricate all the input. It's just that when I encounter porblems like this I'd rather ask the people that do this everyday rather than trying to figure it out on my own and loose a $2000 perfectly good model. I've noticed on the BME website that the Yak video shows some small wing rocking, but not as bad as my model. I initially thought it may have been the wind but no fat chance, I tried it ona d dead calm day with the same results. David |
RE: Cannot get wings to stop rocking!!
Some planes rock,some dont. Ive seen Caps and Extras that lock in and never rock, like a foamy. Even if you never did a harrier planes like that make it easy to do,too easy. Sounds like to me you got used to the way the Cap harriers and the Yak needs something. I myself have never had a plane that didnt rock some,the best was EF Yak(68" wing),it did rock but so gently you could ignore it,I chose to correct it with right aileron. I would hit right ail just as the right wing tip was about to come up, this would stop the rock for a few seconds,the more wind,the more often you need correction. I would try the Yak in the least wind possible,in the AM or PM,get it down in light winds first,then you'll have it down when its not optimum conditions. You might even need full right ail or continuous ail,what ever it needs. I used to hold full right aileron at times,being in HA,it never snapped out on me,just enough authority in that attitude to correct the rock,if you drop the nose suddenly,then it could be a problem. On the other side,if you were lucky enough to have a plane that doesnt rock,keep it.
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RE: Cannot get wings to stop rocking!!
So now I'm thinking of what BodyWerks said, about the sweet spot being possibly greater than 45 degrees. I had a plane like that. I would start in a stable hover and slowly relax the nose. The airplane would move offstill almost in a hover. Gradually I got better and better at it and in time was able to harrier it around like normal, though still at a pretty high AOA. I'm still thinking, too, like Mika and I said, there may be a level of correcting you might need to slip into. Really fast anticipations of what its going to do. Like I said, I learned this in G2 and if you've every flown that sim, the airplanes rock so violently they sometimes snap and go inverted. By now I can harrier the sim planes around upright and inverted, so when a model tries that on my I say, "no you don't!" David, I'm in no way minimizing your problem, just looking for ways out. Do you have a practice plane? I always work out new stuff on something small and cheap. Silversurfer calls 'em slimers which i thought was funny so I have been too.... I'm thinking of something that isn't as sublime as a Mojo, but like a Flip 3D, or an Extreme 330. Something that's going to give you a bit of a hard time. Ok, now you can tell I'm bored because I haven't stopped writing yet. In the early 1980's I really liked WWll fighters. Most of the models being flown at that time were 60 sized, with very high wing loadings. If you could fly one of those ships weighted down with epoxy paint, etc, you were doing something. So I built one but had never flown a high wing loading plane. So I took my 25 powered little stick and rubber banded hand tools (piers, crescent wrenches, etc) on the wing and practiced. I had to be sooooo careful just turning this thing. By the time I was comfortable the maiden of my Corsair was no problem. I flew that thing all summer and had a wonderful time. In the fall I sold it. The guy crashed it on the first flight. Too high of a wing loading.
Dave |
RE: Cannot get wings to stop rocking!!
I do not have G2, I use IPACS Aerofly Deluxe and to date I haven't seen a model as difficult to Harrier as my Yak.
The Cap would rock some but it was controllable, enought to be able to get it close to the ground and move it along the field with total directional control. Sure it neede some rudder, thr, ail, and elev worked but nothing extraordinary (man I wish that Alitalia was still around!!). My Harrier is way higher than 45 deg, probably closer to 65 deg, but doensn't matter as it behaves the same. I don't think it should be that difficult to Harrier a model, if indeed my Yak is such a pain then is not a fun model. |
RE: Cannot get wings to stop rocking!!
I think you're right. I had that CAP too. Sweet flyin plane.
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RE: Cannot get wings to stop rocking!!
ORIGINAL: FalconWings I use IPACS Aerofly Deluxe and to date I haven't seen a model as difficult to Harrier as my Yak. |
RE: Cannot get wings to stop rocking!!
Do you give bursts on the throttle or do you keep the same setting?
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RE: Cannot get wings to stop rocking!!
Depends on what the airplane is doing. Was that a catch question? :D
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RE: Cannot get wings to stop rocking!!
Regarding the differences in harrier between a Cap and a Yak. The 232 is the plane that all others have come to be judged by when it comes to a harrier. With the exception of a really big Yak I have not seen a plane to date that does it better. The Extras are pretty good at it, but generally perform the maneuver better if inverted. The position of the empennage in relation to the main wing is everything in a harrier. Many models pay close attention to the general appearance of the full scale plane, but miss the tail relationship completely. That will leave you with a plane that looks generally right, but is off the mark in performance. As noted in another post, weight and wing loading bear significantly in the final performance too.
On to props, my opinion is that an 8 pitch prop would be better. I'm one that believes that too many people are over propping the DA 50 and unknowingly suffering a loss in all around performance for doing so. It's a "well he's doing it so I'm going to do it" herd instinct type of thing. You may benefit with the greater pitch in one area, but suffer in many others because of it. |
RE: Cannot get wings to stop rocking!!
No catch. ;) But if you blip it a lot you get more torque forces setting the rocking off. How does it do in elevator? If your elevators are stabile, it will harrier aswell.
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RE: Cannot get wings to stop rocking!!
Lateral balance will effect harriers even if the plane is in trim. I am not saying it is the problem, but per your symptoms it very well could be. Its not uncommon for a plane that is out of lateral balance to fly very well with virtually no trim adjustments, but when you pull hard on the elevator you accentuate the problem . Tor asked a good question. How does your plane do in an elevator maneuver? If it rocks in a harrier it should REALLY rock in an elevator.
Is the plane noseheavy? How much does the plane weigh? |
RE: Cannot get wings to stop rocking!!
All the above posts give great advice..sometimes however it is just the way the plane is designed..You could have 2 Extras from 2 different designer's and maybe one guy stretched the tail a little or has the stab in a different location etc..On my WH Edge I balanced laterally, moved the CG around, reduced the weight..basically tried all the suggestions that everyone has given..Still had the rocking..I learned how to get rid of 80% of it but it takes a lot of minor corrections to keep it smooth..It can be done..it just takes some effort..BTW WH has re-designed the Edge to help with the rocking wings..I think the stab has been moved forward but Im not 100% sure..
OTOH, my EF 87" Yak has ZERO rocking at 45 deg 50..65 etc.. the only time the wings wobble is in a crosswind and even then it only takes minor rudder or aileron to stop it.. |
RE: Cannot get wings to stop rocking!!
I will give it a try on lateral balance. Mymodel is aorund 16~17lbs, which is pretty light for it's size. It is 87" wingspan. My Cap was 80" and weighed the same. It is balanced on the tail heavy side. The manufacturer recomends 5~6" CG point. I'm balancing more at like 7", which is great for many maneuvers.
What is an elevator? I may have done it but not know the name. Isn't that a decending Harrier? If so, Yes I've done it and yes it rocks the same side to side. Now to the pulling deal. I do not start a Harrier with a hard pull from straight and level flight. I typically decend two mistakes high, go to idle and when the model is about to break I give it 2~3 clicks of throttle and snap roll (the model will decend). Then when I stop the snap roll I'm already at 75% or so elevator and ready to Harrier. Looks a lot better than yanking it into submission. But I haven't been doing his lately because of the rocking issue. David |
RE: Cannot get wings to stop rocking!!
OK, some thoughts....The first thing I would try is an inverted harrier. If your wings do not rock in an inverted harrier, then I suspect that the wing incidence is off a bit. It sounds like the wing is effecting the prop blast over the V-tail at high alpha. When performing an upright harrier, the V-tail isn't getting enough airflow. Of course, if your wing incidence gets moved more negative, then you will be able to moveyour cg back without changing the tail incidence...hopefully! This should allow more airflow over the lower portion of the rudder (fat portion). From what I have read here, I agree with you that it is a high alpha lateral stability problem. I'll bet you don't have this problem inverted because there is so much V-tail above the thrustline.
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RE: Cannot get wings to stop rocking!!
Yes elevator is a power off, decending harrier.
The pulling thing just shows you if it's off balance, it doesn't matter how you enter the harrier - if it's off balance, it will rock, depending how big the imbalance is. On another note, too tailheavy is not necesarily a good thing. It may destabilize everything, try to move the CG forward to what the manufactor recommends. Check the lateral balance, move the CG forward and maybe lower your throws on the elevator if they are really high. I my experience, it doesn't work to go crazy on the throws on larger models. Thought I don't know your model , I would say 40 - 45 degs is sufficient, more throw will destabilize things too. Personal theory is that you want the elevators to work (airflow, renoylds numbers on larger models etc.) rather than acting as brakes. I know that moving CG forward and lowering throw may go against other people's normal advice... But as the saying go "too much of a good thing..." |
RE: Cannot get wings to stop rocking!!
ORIGINAL: Tor Yes elevator is a power off, decending harrier. The pulling thing just shows you if it's off balance, it doesn't matter how you enter the harrier - if it's off balance, it will rock, depending how big the imbalance is. On another note, too tailheavy is not necesarily a good thing. It may destabilize everything, try to move the CG forward to what the manufactor recommends. Check the lateral balance, move the CG forward and maybe lower your throws on the elevator if they are really high. I my experience, it doesn't work to go crazy on the throws on larger models. Thought I don't know your model , I would say 40 - 45 degs is sufficient, more throw will destabilize things too. Personal theory is that you want the elevators to work (airflow, renoylds numbers on larger models etc.) rather than acting as brakes. I know that moving CG forward and lowering throw may go against other people's normal advice... But as the saying go "too much of a good thing..." |
RE: Cannot get wings to stop rocking!!
Something that nobody has mentioned yet, at least I don't recall reading it in the htread so excuse me if it has already been mentioned....
Seal the gaps on the control surfaces. I have found that for small models, by that I mean ANYTHING under 35%, this really can help a grat immensely. I don't care how tight your gaps are the airflow through the ailerons will differ on either side and hence they are not operating in a balanced state. This same rule applies the elevator halves as well, just do it if you haven't already, you might be surprised at the results. The lateral balance is crucial and if you have a heavy wing it will start the rocking process every time you pull the nose up and slow down. As NEAR to perfect symetrical elevator throws as can be acheived on dual elevator servo equipped planes is a must. Make 2 pointers from a pair of clothespins and carbon rods that are about 12 inches long and clip them on the elevators. Next cycle the elevators up and down and observe the pointers, do they track each other to within an 1/8th of an inch of each other throughout the arc from full up to full down throw? If they don't fix it so they do. Is the model touchy in a hover in calm air? If so you probably have too much throw or too little expo. If your chasing the plane to keep the nose up and in one place you need to work on getting it stable in a hover where small, quick corrections are all that is needed to hold a steady position. My rule is if you are fighting the plane in a hover you will fight it in other maneuvers as well, like harriers, especially harriers. Too much expo, this will get you every time. I have found that the less the better, but you still will NEED some to be able to smoothly control and correct small errors. The problem is, if you use too much you will always be behind the plane every time you attempt a correction. If you use to little your corrections will have to be almost perfectly timed and executed. So how much is too much expo? I've found that most planes are happy with between -20 and -30(Futaba or Hitec) on the rudder and about the same on the elevator, sometimes a bit more but never more than -35. It seems that once you start cranking in more than -35 the controls it's extremely difficult to maintain any feel for the plane as the controls become far too soft. Sure I know some guys that can fly this way and I know just as many that use no expo at all....most of us are not goine to be successful if we try flying in either of these categories IMO. Servo blow back can also be an issue that many might neglect to check for. Make sure your controls are maximizing servo power and resolution. I can't recall the number of times that I helped a guy out at the field or on-line by telling them to move their clevises all the way out on their horns and in some on their servo arms and then fly the plane. Without fail they noticed a big improvement in control response immediately even though their control throws were sometimes cut nearly in half. It's my humble opinion that more guys get into trouble by worrying about having big throws than any other single issue, all of my planes use about 30 degrees on the rudder and elevators and will do whatever I want, ailerons are a matter of personal preference so set them up for a roll rate that doesn't give you a headache and fly it. |
RE: Cannot get wings to stop rocking!!
Nice post, Scott. I find the too much expo makes me feel like i always want to grab another handful, if you know what I mean. The gap sealing thing is new to this thread. I find I can get away with less throw than you'd think, especially with larger models. On my smaller ones I make sure 3D mode has those extreme throws. Interestingly, though, I often prefer hovering and doing TR's in normal mode. At this level it shouldn't be about saving a mistake, or getting out of trouble. If that's where the pilot's at the move is going to be a mess no matter what.
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RE: Cannot get wings to stop rocking!!
ORIGINAL: Shogun Something that nobody has mentioned yet, at least I don't recall reading it in the htread so excuse me if it has already been mentioned.... Seal the gaps on the control surfaces. I have found that for small models, by that I mean ANYTHING under 35%, this really can help a grat immensely. I don't care how tight your gaps are the airflow through the ailerons will differ on either side and hence they are not operating in a balanced state. This same rule applies the elevator halves as well, just do it if you haven't already, you might be surprised at the results. The lateral balance is crucial and if you have a heavy wing it will start the rocking process every time you pull the nose up and slow down. As NEAR to perfect symetrical elevator throws as can be acheived on dual elevator servo equipped planes is a must. Make 2 pointers from a pair of clothespins and carbon rods that are about 12 inches long and clip them on the elevators. Next cycle the elevators up and down and observe the pointers, do they track each other to within an 1/8th of an inch of each other throughout the arc from full up to full down throw? If they don't fix it so they do. Is the model touchy in a hover in calm air? If so you probably have too much throw or too little expo. If your chasing the plane to keep the nose up and in one place you need to work on getting it stable in a hover where small, quick corrections are all that is needed to hold a steady position. My rule is if you are fighting the plane in a hover you will fight it in other maneuvers as well, like harriers, especially harriers. Too much expo, this will get you every time. I have found that the less the better, but you still will NEED some to be able to smoothly control and correct small errors. The problem is, if you use too much you will always be behind the plane every time you attempt a correction. If you use to little your corrections will have to be almost perfectly timed and executed. So how much is too much expo? I've found that most planes are happy with between -20 and -30(Futaba or Hitec) on the rudder and about the same on the elevator, sometimes a bit more but never more than -35. It seems that once you start cranking in more than -35 the controls it's extremely difficult to maintain any feel for the plane as the controls become far too soft. Sure I know some guys that can fly this way and I know just as many that use no expo at all....most of us are not goine to be successful if we try flying in either of these categories IMO. Servo blow back can also be an issue that many might neglect to check for. Make sure your controls are maximizing servo power and resolution. I can't recall the number of times that I helped a guy out at the field or on-line by telling them to move their clevises all the way out on their horns and in some on their servo arms and then fly the plane. Without fail they noticed a big improvement in control response immediately even though their control throws were sometimes cut nearly in half. It's my humble opinion that more guys get into trouble by worrying about having big throws than any other single issue, all of my planes use about 30 degrees on the rudder and elevators and will do whatever I want, ailerons are a matter of personal preference so set them up for a roll rate that doesn't give you a headache and fly it. He speaks.....[X(] Excellent post Scott. Every bit of that is excellent information IMO. I had not thought about the gaps but you are right on. On the expo and how it effects response, for me, it depends on the amount of throw you have. For me, the less throw I have the less expo I need. I judge this by getting my low rate expo exactly where I want it first. Once I have the low rate expo and throw setup just right I go into the high rates and look at the curves on the transmitter screen. My 9C and 9Z both have a chart display that let you see the curves and you can actually see the curve move as you manipulate the expo on the transmitter. What I try to do I set the expo on high rate so that at the bottom of the curve (around the neutral point) on low rate and high rate match. Basically that means that while looking at this screen you flip the rate switch back on forth and the high/low rate curves are exactly the same within say 25% of center. Beyond 25% the low rate curve will actually not curve all that much (less expo = more linear) and the high rate will sharply curve upward and the expo loses effect as you increase throw and the control moves rapidly towards full deflection (more expo= less linear/bigger curve.) However, on the rudder I do not use dual rates on a 3D plane. I am always setup for max throw which may be as much as 50 degrees or basically all I can get. Then I dial in about -60 expo, what that does is makes the rudder "feel" like it is on low rates whn I am trying to make feathering rudder corrections, but when I am hovering or doing a rolling harrier where I am using a lot of deflection anyway, at the point out on the curve where I am operating the expo has become uneffective and I have that linear feel. This only really works for me on the rudder though. I cannot make it feel right on the elevator or ailerons, ESPECIALLY the elevator. There I use dual rates. I am not disagreeing with you in any way, I think your comments are right on. Just interjecting a little detail on how I have found to make good use of expo.[8D] |
RE: Cannot get wings to stop rocking!!
Good points, Mike. I find I do like dual rates on the rudder. Even while doing 3D, I like to fly up and do a nice, long slow roll (the pattern thing, remember?) to break things up. Its just easier for me to nail this kind of move using rates. Also, when doing rolling harriers I find I still over control the rudder if I don't have it on a lower rate. So I set up my third rates as like a specialty rate, with everything high except the rudder. This will probably change as I develop.
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