Lots of Right aileron

[dogman]

Went out to the airport the other day to take the Six up to an A/P to have the New throttle cable adjusted for it would not idle down as far as it had before. I have to take it to a A/P as there is NONE on my airport EZZ. So when I feel that it is safe I will take it to a airport 50 miles away for work. I also wanted to change some of the fuel tank drain sumps for they had been leaking some.

While doing my preflight the Right tip tank was about 5gals and I had left it full (17gals)after the last flight(12 days ago). The right main had about 10gals, left main 10gals, left tip FULL. The right tip had one of the drain sumps that had been leaking. So I finished the pre flight and deemed it safe and started ,run up READY.
About a 12 knot Right X-wind so Holding right aileron for x-wind as I am rolling out staying in the center No drift as the plane started to get light I kept having to roll in more Rt aileron and as the plane lifted off I had to hold a lot of pressure on the yoke to keep the right wing Down. As I had a good climb rate and no chance of settling tried to crab into the wind for climb out. Everytime I tried the plane would aggressively roll Left.
It was pretty exciting Until it dawned on me. Left tip full, right tip all but empty Im setting on the left side (280lbs). Flew to the shop holding right aileron. Flew around enough to even the fuel to release the right aileron before landing. If I had let go of the yoke it would have rolled over into a 90deg. bank.

I am so mad at myself that I did not think about the effect and how out of balance this would make the Plane. Glad I kept the right wing down during take off.
WHAT IF HAD BEEN A LEFT X-WIND?????

Some of you had told me before to manage the fuel to keep it balance Never doubted you but the point is well understood now.

OK let me have it!

Dogman

 

[NC Pilot]

Heard a similar story to yours where someone was flying with an autopilot in a Lance (I think) and failed to switch tanks. Disconnected the AP to land and the plane banked hard toward the full tank.

Sometimes the best lessons learned are the hardest. I believe this one will stick with you for a while.

 

[Michael]

just curious why some planes have this effect and others dont. Is it the size of tanks and or location of the fuel? I can run my tank dry on one side and land with a full tank on the other without ever noticing a difference.

 

[Unregistered]

just curious why some planes have this effect and others dont. Is it the size of tanks and or location of the fuel? I can run my tank dry on one side and land with a full tank on the other without ever noticing a difference.

Location makes a big difference. The tip tanks are furthest from the CG and therefore have more roll moment.

 

[SkyHog]

just curious why some planes have this effect and others dont. Is it the size of tanks and or location of the fuel? I can run my tank dry on one side and land with a full tank on the other without ever noticing a difference.

I can tell you that I certainly notice a difference in my Cherokee. I'm fat, so I always burn the left tank first. Otherwise I'm constantly correcting.

Good question!

 

[Greg Bockelman]

just curious why some planes have this effect and others dont. Is it the size of tanks and or location of the fuel? I can run my tank dry on one side and land with a full tank on the other without ever noticing a difference.

There are two factors involved here, Michael. First is how far out on the wing the tank is. In the case of the aux tanks on the Cherokee 6, they are way out on the tip of the wing. Quite a bit of leverage. In a Cessna they are basically at the wing root so there isn't that much leverage. I don't know where yours are on the Mooney.

The other factor is how big the tanks are. The more fuel, the more leverage, no matter where they are on the wing. My tanks are 40 gallons each. I can tell a huge difference when one is full and the other is almost empty and the tanks are at the wing root.

 

[gismo]

There are two factors involved here, Michael. First is how far out on the wing the tank is. In the case of the aux tanks on the Cherokee 6, they are way out on the tip of the wing. Quite a bit of leverage. In a Cessna they are basically at the wing root so there isn't that much leverage. I don't know where yours are on the Mooney.

The other factor is how big the tanks are. The more fuel, the more leverage, no matter where they are on the wing. My tanks are 40 gallons each. I can tell a huge difference when one is full and the other is almost empty and the tanks are at the wing root.

Yep. In my old Bonanza the main tanks were fairly close to the fuselage and balance wasn't that big an issue. The tip tanks OTOH could cause an imbalance you could hardly correct with aileron at low speeds if you let them get very different fuel levels. IIRC there was even a special procedure for landing if there was more than a few gallons difference.