Cessna 172 F

twinbirch · Post by **twinbirch** » Sun Apr 29, 2007 8:56 pm

I recently purchased a C-172F with no damage history. It cruises needing a little left rudder or yoke down to the left in order to prevent left yaw action on the tail. I usually just fly it with the yoke down left to keep it flying straight and level. I noticed the elevator trim tab (on the right side elevator) is not level straight across from one side to the other when in up or down position to the elevator. Looks like its built that way and nothing is bent or twisted. All other 172s have a level trim tab sraight across. Could this be creating enough drag to create the left yaw action? Also there is no fixed rudder tab on the rudder which are installed on the latter models. Should I be looking elsewhwere for this problem?...any suggestions

twotter · Post by **twotter** » Mon Apr 30, 2007 1:45 am

It could be that your wing excentric bushings have not been set right.

These are bushings at your rear wing attach point that will adjust the incidence of the wing. They are independent of each other and can make a huge difference in how the airpane flys..

If you would like more info on rigging your airplane, please feel free to pm me as it's much easier than using the board..

Cheers
Dale

itismedd · Post by **itismedd** » Mon Apr 30, 2007 9:37 am

It sounds to me that your ailerons maybe out of rig. A quick way to tell is make sure your ailerons are in the neutral position. Its been awhile but if you remove the outbd panels and set the aileron stops in the neutral position, once that is done look at your ailerons and your control column. If your ailerons are in streamline with your flaps and your control column is not level then your rigging is out under your intsrument panel, if your control column is level but your inbd TE of your ailerons are not streamline with your flaps in the up position than your pushrods may need adjusting. Either way sounds like you should take it to your AME.

twinbirch · Post by **twinbirch** » Mon Apr 30, 2007 3:30 pm

Thanks guys........time to visit my AME

KISS_MY_TCAS · Post by **KISS_MY_TCAS** » Mon Apr 30, 2007 4:55 pm

I have come across this before and was going to go after the wing eccentrics, but elected to look at control surface rigging before sweeping the wings like itismedd mentioned. I found that the rudder was incorrectly rigged in the neutral position, there should be a couple of degrees of deflection at the rudder with the pedals centered (can't remember exact numbers, it is in the maintenance manual which I don't have here). The rudder on this particular plane was rigged to 0° with the pedals centered, and it was enough to cause the same symptom you are having. Have your AME check the neutral position rigging on your control surfaces.

twotter · Post by **twotter** » Mon Apr 30, 2007 9:46 pm

KISS_MY_TCAS wrote:I have come across this before and was going to go after the wing eccentrics, but elected to look at control surface rigging before sweeping the wings like itismedd mentioned. I found that the rudder was incorrectly rigged in the neutral position, there should be a couple of degrees of deflection at the rudder with the pedals centered (can't remember exact numbers, it is in the maintenance manual which I don't have here). The rudder on this particular plane was rigged to 0° with the pedals centered, and it was enough to cause the same symptom you are having. Have your AME check the neutral position rigging on your control surfaces.

You know, I've thought about this a bit and think you guys may be more on the ball than I was. There of course is a lot of things to look at and I think I may have knee jerked in my answer. I would defineatly agree to check the flight controls before playing with the excentrics. I guess I have to think before I react some times.. My bad..

KISS_MY_TCAS · Post by **KISS_MY_TCAS** » Mon Apr 30, 2007 10:27 pm

No sweat twotter, it was one of those snags that was a rarity, I seldom work on piston singles so spent a lot of time researching that particular problem which is why years later it still stands out in my mind. That combined with the probability of adjusting the eccentrics for the first time ever on a Cessna, before that day I didn't even know those things existed

. Happy to say to this day I have never needed to adjust any Cessna wing eccentrics

.

twotter · Post by **twotter** » Tue May 01, 2007 12:51 am

Hey, I just went through it, we just did a bit of an overhaul on our one and only Cessna and when I put it back together I was kinda worried about the excentrics, I hadn't played with them for 20+ years and hoped we put the wings back on the way we had taken them off(I'd marked the excentrics but never trust that).. Well, I went out and we did the test flight last Friday and holy sheite.. it worked, it still flew straight and boy does that little sucker haul.. 130+kts... Gotta love the CAP floats..

itismedd · Post by **itismedd** » Tue May 01, 2007 12:12 pm

Hey no problem twinbirch.

twinbirch · Post by **twinbirch** » Tue May 08, 2007 3:27 pm

Thanks again everyone that was great! :)

Cessna 172 F

Cessna 172 F

Cessna 172 f

172f