First try at tip tanks, almost crashed

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bobsk8
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First try at tip tanks, almost crashed

Post by bobsk8 »

I am on a several hundred mile VA flight in the Bahamas this morning, and decided to try the tip tanks for the first time. I switched to left tip tank when a few thousand feet from my cruise altitude. After about 15 minutes, I noticed that my Comanche was veering off the flight path to the right The autopilot was unable to hold the heading, and the bank to the right got worse and worse. Next thing I notice is that I am entering a death spiral to the right, with altitude decaying like crazy, and airspeed past redline

At first I suspected an AP problem, which I disengaged, pulled gently out of the dive and got back to straight and level. Then I noticed that I had to hold control wheel to the left, otherwise the aircraft would bank to the right. I looked at outside view, and the ailerons were set for a left bank when I could hold straight and level. Finally it occurred to me to check the fuel in the left tip tank, which was almost empty (4 gallons) . Right tank was full. All that extra weight on the right wing tip was causing a steep bank to the right, which the autopilot could not correct. I lowered the fuel in the right tip tank to 4 gallons, and back to straight and level flight.

So I guess correct tip tank procedure should be to alternate left and right tip tank fuel usage to keep them balanced.
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MkIV Hvd
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Re: First try at tip tanks, almost crashed

Post by MkIV Hvd »

bobsk8 wrote: 14 Sep 2019, 09:34 So I guess correct tip tank procedure should be to alternate left and right tip tank fuel usage to keep them balanced.
Umm... :shock: ...good idea!! :wink:
Rob Wilkinson
A2A: Civilian Mustang, T-6, Bonanza, Comanche, Cub, C182, Spitfire, P-40, Cherokee, P-51 - VATSIM P4 and some other stuff...

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bobsk8
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Location: Atlanta, Georgia

Re: First try at tip tanks, almost crashed

Post by bobsk8 »

On a 300 mile flight now for my VA, so I am going to try something different. Got up to cruise altitude, and now I turned on both Tip tanks instead of just one. I suspect that the tanks will drain at the same rate which should not cause a weight unbalance like I had before. Will report back the result.
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bobsk8
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Re: First try at tip tanks, almost crashed

Post by bobsk8 »

Ran both tip tanks at the same time, drain from each tank was equal. No weight imbalance issues at all.
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MkIV Hvd
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Re: First try at tip tanks, almost crashed

Post by MkIV Hvd »

That's good to know and much easier than constant switching...just monitor to ensure they keep draining at they same rate...but of course if they don't, you'll now know what's going on a lot sooner than the first time!
Rob Wilkinson
A2A: Civilian Mustang, T-6, Bonanza, Comanche, Cub, C182, Spitfire, P-40, Cherokee, P-51 - VATSIM P4 and some other stuff...

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