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Switching to fullest tank on landing


ragedracer1977

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On 10/6/2017 at 11:18 AM, gsxrpilot said:

Interesting... this seems like a lot of opportunity to lose track, mess up the sequence, mis-calculate, along with a lot of work on the tank selector.  

I'm carrying 35 gal per side and only ever switch tanks twice, if that much. 

I used to change tanks on my Cherokee every half hour, had a little timer to remind me.  But I had fuel switch that I could operate without unbelting myself and giving myself a blow job.  Now I burn for an hour on one side and lots more on the other.

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3 hours ago, gsxrpilot said:

Interesting... this seems like a lot of opportunity to lose track, mess up the sequence, mis-calculate, along with a lot of work on the tank selector.  

I'm carrying 35 gal per side and only ever switch tanks twice, if that much. 

Pretty hard to mess it up with Cies floats and a digital fuel gauge though.

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8 minutes ago, steingar said:

I used to change tanks on my Cherokee every half hour, had a little timer to remind me.  But I had full switch that I could operate without unbelting myself and giving myself a blow job.  Now I burn for an hour on one said and lots more on the other.

Ah, the infamous fuel switch BJ. Dr. Ron built me a fuel switcher gizmo out of PVC. Works great. I just want to know what ergonomic engineer came up with the selection of the location for the selector valve on these older Mooneys.

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2 minutes ago, Marauder said:

Ah, the infamous fuel switch BJ. Dr. Ron built me a fuel switcher gizmo out of PVC. Works great. I just want to know what ergonomic engineer came up with the selection of the location for the selector valve on these older Mooneys.

It is the simplest place to put it. Anywhere else will be more complex.

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5 minutes ago, N201MKTurbo said:

Huh, I'm a tall skinny guy with long arms. I have no trouble seeing it or switching it.

Only problem I have with the location is if it's the end of a long flight, I really need to use the restroom, and I have to reach down to switch it at the top of my descent...:huh:

Maybe I need one of those relief tubes. ;)

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Maybe it is in part reference to the following 'Warning' from the M20J POH, which I am sure is the same as the M20C POH:

"Takeoff maneuvers, prolonged sideslips or steep descents when the selected fuel tank contains less than 8 gallons (48.0 lbs., 30.3 litres, 6.7 IMP. Gal.) of fuel have not been demonstrated and may cause loss of power"

I couldn't figure out how to display the exact page, so I just typed the info as written.

In the absence of a stall, low fuel below 8 gallons in the selected tank was found to be the most likely causal factor in a fatal Mooney accident in Western Australia some years ago when the pilot did a steep bank in the circuit. 

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5 minutes ago, jetdriven said:

If the steep bank is coordinated, then why would it matter to the fuel in the tank? What changes?

Good question Byron.  An unqualified guess; maybe it has to do with possible unporting of fuel in the tank due to an uncoordinated steep bank and Mooney are simply catering to that scenario? However, the wording does not imply either coordinated or uncoordinated.  I'm sure there a technical answer out there.

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2 hours ago, Mooney in Oz said:

Maybe it is in part reference to the following 'Warning' from the M20J POH, which I am sure is the same as the M20C POH:

"Takeoff maneuvers, prolonged sideslips or steep descents when the selected fuel tank contains less than 8 gallons (48.0 lbs., 30.3 litres, 6.7 IMP. Gal.) of fuel have not been demonstrated and may cause loss of power"

I couldn't figure out how to display the exact page, so I just typed the info as written.

In the absence of a stall, low fuel below 8 gallons in the selected tank was found to be the most likely causal factor in a fatal Mooney accident in Western Australia some years ago when the pilot did a steep bank in the circuit. 

Seems kind of worrisome that they never tested whether or not it was safe to fly the plane with an hour of fuel remaining.

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There are two ways to unport the fuel from the pick-up...

1) lower the nose... (fuel runs forwards, away from the pick-up)

2) use uncoordinated flight... (fuel runs towards the wing tip, away from the pick-up)

3) If you can visualize where your fuel pick up is, you probably won't fall victim to unporting...

4) If you maintain coordinated flight, you probably won't fall victim to unporting...

4.1) If you can keep the fuel in the uphill wing while slipping, you probably won't fall victim to unporting...

5) If you want to test out your unporting flying skills, use minimum fuel on a post maintenance flight. When you point the Nose towards the numbers, it may get a little quieter....outside.  Inside, it may get a little louder depending on who you brought with you and what you told them in advance...

6) roughly speaking.... a good side slip with a strongly lowered wing, will have the fuel running toward the wing tip.

7) if you are carrying minimum fuel, expect to have the fuel in the uphill wing...

8) you can either use g-forces or gravity to encourage fuel to leave the tank in an orderly fashion...

9) Keep the flight coordinated to use the g-forces in an expected way.  Or keep the wing that is supplying fuel, above the fuel pick-up...

10) if flying around with eight gallons in one tank, you would have to try pretty hard to unport the fuel without knowing it.  You have lowered the wing without intending to turn...

11) when planning a deep slip, make sure the fuel is being drawn from the uphill wing...

12) If the fuel isn't in the uphill wing... Crab and kick is going to be your friend...:)

Just An ordinary PP's way of looking at this challenge...

Best regards,

-a-

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On 10/5/2017 at 1:41 AM, Skates97 said:

This is a great point. When I am switching tanks prior to landing I do it before beginning my descent. I was taught that you want to switch while flying straight and level so that's what I do. Maybe that's just an OWT, I I don't know. 

I've actually removed the fuel item from my before landing checklist and moved it back to descent.

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