Wing rock

[WTF]

Whats with planes wing rocking during a harrier. Seems like everything I have had does this but some are worse then others. Tried spoilerons with a little success. Why does this happen and what can be done to stop it? Any ideas?

[TonyThomasian]

You want your CG back, you want the nose of the plane facing at a realy high alpha attack, you want to play w/ the throttle untill you can find the "sweet spot" for each of the airplanes you want to harrier with.

[PlanePlanter]

The "sweet spot" is different for every plane as well, but once you find it, it's like it gets "locked" in. Keep trying, you'll find it!

[Vic3D]

Keep your eyes PEELED on the aileron control. That's the only true way to maintain a rock solid harrier is to have good aileron reflexes. Tail heavy and spoilers will help ya, but you can still do it. Practice pratice

Vic

[flyin woodbutcher]

tail heavy is not the answer, a rear cg is needed. There is a point in the cg where it will harrier better. I have a new Fiber-lite Edge 540 I've been dialing in and at a 1/4 in behind the recomended cg the plane was rock steady. Kept moving the cg back and at about 1.5 in back I noticed I was fighting the wings , still ok but before it was childs play rock steady. Then I changed the prop from a 22x10 to a 23x8 , wings were rocking like a Sig kadet then. Who knows why , something changed the sweet spot. I moved 3 ozs back toward the front to put the cg at 3/4 back and put the Mej. 22x10 back on . I am still amazed that I am now able to harrier low and slow.

So , there are a lot of variables that need to be tried to find out the sweet spot that the planes likes. Once you find this and the wings settle down the fun begins.

FWB

[JoeAirPort]

Like Vic said, stay ON the ailerons and dampen that rock the first time it appears. Pretty soon no one will even see it and you will forget all about it since your thumbs will do it all by themselves. At first you will need to program your noggen to add the little bumps of aileron inputs, after that it just comes naturally. This manuever takes perfect control of all stick inputs to do it smoothly. Practice is everything. Setup is important, no doubt. There are some models that just do it better than others. The bigger the better of course, but my BME Edge 30% harriers better than many planes out there, it's just a good design.

PS: Very important, do not keep pushing the aileron stick back and forth with large inputs. It will just rock out of control. Just add a little bump of aileron, back to neutral, watch it fly. Do it again when it starts to rock, it usually settles out after a few of these. This has to be done to a small extent the entire duration of the manuever. If there are a lot of wind gusts, you have to stay on it the entire time (especially smaller planes).

[wildhare]

There is a lot of debate about this. Many pilots have an opinion but none seem to be really based on facts and they often conflict.

Here is a paragraph from Don Sczur, former TOC pilot, on the subject of wing rock. The plane's design will have something to do with it, the more the rudder is clear of turbulence coming off the h-stabs the better. This is why a Cap does such a nice elevator and harrier, it's h-stab set is well forward of the rudder. Some of our (Wild Hare) planes have been tweaked a little to give this effect and it has worked well to tame wing rock.

"The final basic 3D maneuver is called the Harrier/Elevator. Basically, enter this maneuver medium altitude (several mistakes high) and slow the plane down. Pop in the up elevator and the nose will come up with the wings partially stalled- with the plane settling in a vertical decent and the nose level with the horizon (low throttle) demonstrates an Elevator. A Harrier is a variant of the Elevator- the plane begins to fly at the same altitude with the nose pointed up about 30 degrees (medium throttle). Here is the trick. The wings may begin to rock- at which time you adjust the elevator, rudder and aileron to reduce the oscillation. Wing rock is a normal occurrence and takes place when the horizontal stab partially blocks the vertical stab. You can reduce the elevator input momentarily as the wings cross level, which will damp out the wing rock. There are two other techniques to use in order to reduce the oscillation. First is through control surface trim- turn out each aileron clevis to move the ailerons "up" by about 1/8 inch. The second is to adjust the 3D elevator rate to "tune" in the best alpha angle, which reduces vertical stab turbulence. For example, one may need slightly less than full up elevator to settle in to nice harrier flight. From there you steer with the rudder, and if needed a little aileron."

Tom Fawcett
Wild Hare Hobbies

[macanaw]

Answers to these questions might yield better input.

What Plane?
Whats the weight?
How much elevaor throw do you have?
Are your elevator throws exactly the same at full deflection?

Mac