C150 tracking issue

Peter Ha

Peter Ha

Pre-takeoff checklist
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Nov 18, 2019
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Hey folks,
Now that i'm getting to know my plane better; i've observed following.
Since putting 41 hours in my 150, I noticed during cruise; there's slight yaw-left tendency. And maybe very tiny bit bank-left tendency also. What could be cause of this?
 
What Bob said.

Also, is it the same over all power settings?

Is there the same amount of fuel in each tank? A fuel imbalance can cause it.

is it the same solo or with two onboard? Same as above.

Yaw issue, is it the same at all power settings? You may be able to bend the fixed trim tab on the rudder to alleviate some of that.

But really, if it is slight, I would personally just live with it.
 
My 150 always flys left too. I imagine it is out of rig, but then sometimes with two people aboard, or when the sun shines just right, it flies straight. Not sure if I will spend the cash to try to rig it straight. Unfortunately I do not have an adjustable rudder tab on my 150F.
 
This is a common problem. As soon as you reach safe altitude, select left tank, and as the fuel burns out of the left tank, your weight will be balanced by fuel in the right tank. I did that in both 150's and 172's when flying solo. We had a trim tab on the rudder, but again, be sure that you are correcting for when the side to side balance is correct, or you will be chasing the ghost forever. After the weight is balanced, alternate tanks every 30 minutes, and be sure that you go to BOTH for landing.
 
We farted around with fuel this, who sits where that. Then our mechanic is just said its flying pilot wing heavy, rotated the wing slightly (easier than it sounds) and now it's almost perfect. Not saying to go here first but you might end up there.
 
150F model at least only has on-off fuel. No switching tanks.
 
As other have said it’s pretty common. Need to change the incidence of the wing using the cam bolts in the wing root. Not very difficult and only takes maybe an hour to make an adjustment or less. It does take some patience and some long extensions.

make sure with the flaps in the up position that the trailing edges of all the controls line up.
 
Grum.Man said:
As other have said it’s pretty common. Need to change the incidence of the wing using the cam bolts in the wing root. Not very difficult and only takes maybe an hour to make an adjustment or less. It does take some patience and some long extensions.
Click to expand...

It ain't nearly that simple. When those eccentrics are rotated, they not only raise or lower the trailing edge, they shift the wingtip forward and back, as the aft spar moves in and out. And as that spar moves, the aileron and flap cable tensions go all wonky, so now, if you're a consciencious mechanic, you re-rig all of that, too. Otherwise the controls are sloppy or tight. And either can cause damage.

The Cessna rudder system is rigged at the nosewheel, but I have found them far off when mechanics fooled with the threaded connections at the rudder instead. The nosewheel locks straight-ahead when the airplane is in flight, and it centers the rudder. The steering bungees have to be adjusted just so, so that in straight flight their rods are against their internal springs but not compressing the springs, and not loose. Anything else results in the airplane wanting to do something it shouldn't.

It's all in the manual, but looking it up is such a pain....
 
Rigging is best left to a certificated mechanic and ideally one that has done that model aircraft previously. It's definitely not something an owner is allowed to do unless under the direct supervision of a mechanic.
 
Dan Thomas said:
It ain't nearly that simple. When those eccentrics are rotated, they not only raise or lower the trailing edge, they shift the wingtip forward and back, as the aft spar moves in and out. And as that spar moves, the aileron and flap cable tensions go all wonky, so now, if you're a consciencious mechanic, you re-rig all of that, too. Otherwise the controls are sloppy or tight. And either can cause damage.

The Cessna rudder system is rigged at the nosewheel, but I have found them far off when mechanics fooled with the threaded connections at the rudder instead. The nosewheel locks straight-ahead when the airplane is in flight, and it centers the rudder. The steering bungees have to be adjusted just so, so that in straight flight their rods are against their internal springs but not compressing the springs, and not loose. Anything else results in the airplane wanting to do something it shouldn't.

It's all in the manual, but looking it up is such a pain....
Click to expand...
We are MEN. We don't need no steeenkink manuals!

But, we should.
 
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UngaWunga said:
Maybe sit in the middle?
Click to expand...
Anyone here remember Eamon Macenzie? "Flying low and slow over Long Island"? last heard from when he joined a Regional Airline, then I lost track of him.

Eamon used to fly his 150 from the middle frequently. -Skip
 
Airplanes are funny things, some fly hands off really well in normal cruise power settings with a pilot and passenger, if so then you load it up to max gross weight and use higher power settings and it no longer flies hands off. Or maybe it flies hands off with only the pilot at certain power settings.
 
The C150 fuel system is either on or off, no way to balance. It is common for one tank to feed till it's almost empty at which time the other tank begins to feed. If it's the right tank that feeds and the solo pilot is in the left seat, it's not uncommon for even a properly rigged airplane to have a heavy left wing and a resulting left turning tendency.
 
Cessna Pilots Association (CPA) in Santa Maria, CA offered a class for A&Ps in rigging Cessnas for straight and level hands off flight, and CPA members who had graduates of the course rig their airplanes were universally pleased with the results. CPA published a list of course graduates, but the last one I have is from 2003, so there's no telling what the status of any of them is currently. If interested, the names could probably be searched in the FAA Registry for current contact info.

Here are the names of course graduates I have in Southern California from the 2003 list:

Richard Anderson
FAST Aviation, Inc.
4015 N. Santa Anita Ave.
El Monte, CA 91731
626-533-2559
rkaone@earthlink.net
R02-02

Emitt Hamm
Santa Ynez Aviation Inc.
P.O. Box 1784
900 Airport Road, Hangar G9
Santa Ynez, CA 93460
805-688-1224
emitt@santaynezaviation.com
R02-02

Robert Butt
ParaAviation
1993 Aviation Dr. #5
Corona, CA 92880
909-737-7489
parair@linkline.com
R02-02

Jere R. Calef
2884 Del Mar Ave
Mojave, CA 93501
661-824-2839
skywagon@antelecom.net
R03-01
 
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