Lateral Balance

E

evapilotaz

En-Route
Joined
Feb 13, 2012
Messages
2,623
Location
Gilbert AZ. VFR All Year Baby
Display Name
Drone airspace abuser
Home Airfield
KCHD
Question about Lateral balance for you all. Say I'm flying an Archer with Someone that is 230LB and I'm at 163lb. Is the airplane out of balance Laterally? Meaning I have to always be correcting with Aileron.

Thanks as always.
 
My understanding is that you are so close to the center of gravity (your shoulders are touching, right?) that the difference is negligible. Think about when you fly alone. That's 163 pounds vs 0.
 
Not significant. You fly solo, right?

Some airplanes may have a significant effect from fuel tanks, especially with tip tanks. Such airplanes will have fuel imbalance limitations if any configuration can exceed the envelope.
 
Again, not significant.

As an aside, Cirrus allows no more than a 10 gal imbalance as a Limitation.

Rumor has it it's an autopilot concern, in that it was only tested to that imbalance.
 
Be thankful that you are not flying a helicopter, where you have to calculate two weight-and-balance worksheets, one for longitudinal and one lateral c-of-g. If either one is outside the envelope, it's a no-go.
 
Weight times arm equals moment. If the tanks are way out on the wing they have a very large moment. If your buddy is sitting right next to you on the other side of the longitudinal CG the moment is very low.
Also makes a difference if the wings are long or short. My T craft had no issues with the right wing tank empty or full....6 gallons in the right wing root only. I never had any problems with big guys in the right seat either. I weight 135lb at the time. On the other hand my buddy had a Grumman AA1A with the little short slab wings and we found that swapping seats changed the direction the plane drifted in flight. (not changing in flight....tough enough on the ground).
 
BiffJ said:
On the other hand my buddy had a Grumman AA1A with the little short slab wings and we found that swapping seats changed the direction the plane drifted in flight.
Click to expand...

You can fly a well trimmed small plane in smooth air by weight shift, hands and feet off of the controls and pilot leaning this way and that. I used to like to do it in my Cherokee 140
 
FastEddieB said:
Again, not significant.

As an aside, Cirrus allows no more than a 10 gal imbalance as a Limitation.

Rumor has it it's an autopilot concern, in that it was only tested to that imbalance.
Click to expand...

I once worked on a Cirrus that had been 'chuted after the fuel imbalance got out of hand. The autopilot ran out of aileron travel (ailerons hit the stops) and the pilot apparently could not stop the subsequent roll. And the problem there becomes an unrecoverable issue, even with rudder to try to hold the wing up, since the full tank is in that low wing and its tank probably unported.
 
I notice lateral stability more with fuel unbalancing than anything in the cabin. When I fly solo (I'm 235 lbs), any unbalancing is negligible.
 
A lot of airplanes fly "wing low". Pick up the low wing with the ailerons and you turn, pick it up with the rudder and you slip or skid. Oh well....nothing is perfect....
 
Many times I've had up to a thousand pounds of lumber loaded on the passenger side and had no problems in my C-180. Aft CG is a much bigger worry. Off center weight is more noticeable when further below the wing, like with an external load on one float. The plane flies fine but controls can be a little sluggish.
 
You must log in or register to reply here.
Back
Top