Heavy Wing

[50kilofox]

My PA 22/20 has a "heavy" rt wing. In cruise @ full throttle, with the ball centered, I need 1/4 turn of yoke to left to fly straight. I saw someplace that the solution is to bend the vertical stabilizer at the top, in the direction of the heavy wing. The ailerons and yokes are perfectly aligned on the ground. Any ideas?

[Rudder Bug]

One of your wings might have less washout than the other one.

Mine was flying perfectly straight before I took it apart for a paint job.

When I got her back together, I ended up with a heavy right wing just like yours. A look from the front of the aircraft and a level showed that my right wing had a little less incidence than the left one.

I gave the rear fork one turn to increase the angle of incidence and went flying. It was a little better. I did it two more times and she was flying hands off beautifully.

Giles

[Curly]

Sounds like it may need re rigging - search "Rigging" on this site for THE BEST advice you can find on how to rig your aeroplane to fly as it should.

[Rudder Bug]

Curly is right.

You will find a fontain of priceless information on that site:

http://home.earthlink.net/~andy2220/id4.html

[this-is-steve]

Before you do too much take a moment and make sure the ball in centered when the aircraft is level on the ground. I have re-rigged many airplanes simply by properly adjusting the turn coord.

If that doesn't work, then start rigging.

Steve

[JohnW]

A heavy wing indicates a rigging problem, for sure. However. "Tweaking the vertical fin" is the absolute LAST resort. The fin SHOULD BE slightly offset "forward end off to the left side" about so as the top edge of the fin "points" at a spot APPROXIMATELY 2.5 to 3.5 inches LEFT of the top fuselage centerline, at the windshield aft edge, and this is due to the way the airflow wraps around the airplane at relatively high power settings. However...a "heavy wing" USUALLY means that that wing isn't producing enough lift (and all this is rigged to provide "wings level flight" AT CRUISE SPEED). But just launching into a quick fix isn't the way to go. You do indeed need to start from scratch and rig the airplane to the Piper Rigging Instructions and "adjust after test flying" from there to get "straight and level" dialed in. There is a greater-than-maybe chance that your rigging is ALL screwed up where it is "at" right now.

The rigging instructions are easily found in three locations (not including the "search button")...1) your Piper Airplane Owner's Operating Handbook 2) Andy's site and 3) Piper Service Memos, of which for the PA-22/20 -which is still a PA-22 as far as "this stuff" goes- you would need S.M. No. 21, which will first thing tell you "is a SUPPLEMENT for the PA-20 Rigging Instructions", which is S.M.20. The instructions were written before digital equipment was available in every Shadetree's toolbox, so my first advice is do NOT over complicate the situation by getting tied up with somebody that wants to use their fancy-schmancy digital protractor. But the time you figure out all the things Piper DIDN'T tell you in their rigging instructions when it comes to using a digital protractor, you might be able to write a Doctorate's Thesis on aerodynamic theory (but you WILL have been able to rig THREE shortwings in the time it will take you to figure out). Go with the plumb bob, the string, a six-inch scale and a "spirit" level longer than thirty inches. Without fail, level the airplane first, and make SURE the rudder post, and the horizontal stab/elevs are "level" and/or "plumb". Once you have completed the "basic rig", you will go fly. On the test flight, you should be pretty darn close to properly rigged (stay AWAY from the vertical stab, for now). Then you rig out the discreps, and if you are GOOD ENOUGH, you will do this with nothing but the wing strut forks. If your airplane is "bent", or "whacked", then you MAY actually have to twist the fin to get the last hands/feet off cruise once you have exhausted getting straight and level with the strut forks (and pulled all your hair out). THEN (if it is still installed), you finish the rig of the "interconnect". There simply is no "easy, quick" fix for an airplane that doesn't fly straight. The ONLY way to go is to "start over" and KNOW it is right.

If your ball is in the cage and you need a quarter-turn deflection on the yoke, you very likely have one HELL of a mis-rigged airplane (you didn't mention "the ball"). MAYBE it's just your interconnect springs (if they are hooked up). You need to have BOTH SIDES of your struts "far enough into" the strut barrels to be FULLY ENGAGED with the barrels. That is, not "too many" threads showing on the fork. Doing the "basic rig" from scratch has the sole purpose in life of giving you a GOOD, SAFE airplane to go test fly. Once you have a safe platform to "tweak into" wings level, hands off, cruise flight... you will (usually first) try ADDING LIFT to the "heavy wing" side by LENGTHENING the REAR strut on the heavy wing. If when all told, your airplane cruises substantially slower than "book" cruise, you may pick that up a little by SHORTENING both rear struts a little (but we are getting WAY ahead of ourselves already!). "Lots of washout" is a bit "draggy" and slows you down, but usually makes for the nicer landing airplane. Less washout eventually goes faster, but the stall gets sorta "unpredictable" as to which way the airplane turns when it stops flying.

Oh, by the way...this is NOT "preventative maintenance", and it REQUIRES a certificated mechanic to sign off rigging. In truth, it requires a GOOD Mechanic...one that prides himself on being an Expert in rigging (these are getting harder and harder to find!). So, DO NOT attempt this "without Adult Supervision". A properly rigged shortwing is a fantastic pleasure to fly. As the Pilot, it is POSSIBLE for you to become an expert, through experience. But you NEED to involve somebody familiar with the procedures, techniques and practices.

Again, PLEASE don't just start yanking away at the fin (and you NEVER bend the forward section of the rudder). Over and above "loose fabric", you CAN break the structure of the fin. Yes, there is a LOT of info in the "search bar" about rigging (and a whole lot of it is from ME). But sincerely, if you need to ASK this question in the first place, you really shouldn't be messing around with it by yourself. A well-informed Owner is a wonderful thing. But you need to seek professional assistance with messin' around with rigging.

[Steve Pierce]

You have two choices in my book.
1. Trust the previous rigger and shorten the rear strut on the heavy wing by half a turn.
2. Check the rigging and adjust per this illustrated thread. http://www.shortwingpipers.org/forum...hlight=rigging

Not uncommon to have to slightly adjust jigging after recover. I use a digital level and if both aileron tip ribs are the same it usually flies level. I adjust the vertical fin to eliminate holding rudder.

[Throttle Pusher]

Trust the previous rigger and ""shorten""the rear strut on the heavy wing by half a turn.

Lengthen no shorten, You must be further along with your Christmas cheer than I am tonight.

[mike mcs repair]

Before you do too much take a moment and make sure the ball in centered when the aircraft is level side to side on the ground.
Steve

So true!!!!!!!!! step #1

[Steve Pierce]

Lengthen no shorten, You must be further along with your Christmas cheer than I am tonight.

If you lengthen the rear strut on a heavy wing you have decreased wash-out and lift thus making the wing heavier. Shortening the rear strut will increase lift and raise the heavy wing.