Draining fuel for weight & balance?

[pwnel]

Folks, I keep my 231 hangared always with full fuel for moisture prevention purposes.  (I have brand new gear doughnuts so can afford the extra weight).  The problem is I'm of course overweight when I want to go three or four up for a scenic flight (quite the crowd pleaser when you're close to Manhattan).   Does anyone ever drain fuel from tanks to bring W&B back in range?  Is there an established way to do this?  I also am pretty sure my airport won't like me storing fuel in the hanger (even temporarily to put back after the flight). Interested to hear others' thoughts on this.

[kortopates]

Draining fuel, outside of the hangar, and storing in the hangar are all dangerous activities. Your hangar agreement most likely prohibits Storing fuel in your hangar as well.

These are reason enough most of don't top off tanks till we know our fuel requirements for the next trip.

Perhaps most importantly there is no known benefit to keeping your tanks full versus partially wet; especially in the hangar.


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[201er]

35 minutes ago, pwnel said:

Does anyone ever drain fuel from tanks to bring W&B back in range?  Is there an established way to do this? 

Yes, fly the plane!

Think of it as some free flying. Maybe even go ROP for a bit. Or tell them to find their own ride. 

[Bob - S50]

Yep, that's why we park the plane with 30-35 gallons in it.  Enough to fly a couple hours yet light enough to carry a load.

[N201MKTurbo]

I used to know the crop duster operator at the airport. He had an underground tank. If I had to offload some fuel I would just drain it into his tank and pump it back in when I needed it. But he crashed and the city tore down his buildings.

The easiest way is to make up an AN6 hose. take off the cowl and disconnect the fuel line from the firewall and replace it with your hose. Then pump it out with the fuel pump. This was easy with my old M20F because you could just take off the lower side panel. A lot more trouble in the 201.

[larryb]

I only put full fuel in when getting ready for a long trip. Why carry 5 hours worth of fuel for an hour trip in good weather? My "full" most of the time is 50 or 60 gallons out of 75 max. Don't get me wrong, I like plenty of reserve fuel, but I like a lighter weigh too.

Larry

[pwnel]

2 hours ago, kortopates said:

Perhaps most importantly there is no known benefit to keeping your tanks full versus partially wet; especially in the hangar.
 

Thanks, so if that notion of mine is debunked, then there's really no reason to refuel AFTER every flight like I've been doing. (I'm in a hangar but 5 miles from the ocean and paranoid about any corrosion.)

[Guest]

I have a 55 gallon steel drum on a caddy with a hand pump.  While it is meant to pump from the barrel, t turns out that the pump is bi-directional and will happily pump in reverse once the pump is primed.  You can empty a tank quite quickly with it.

Clarence

[jaylw314]

41 minutes ago, pwnel said:

Thanks, so if that notion of mine is debunked, then there's really no reason to refuel AFTER every flight like I've been doing. (I'm in a hangar but 5 miles from the ocean and paranoid about any corrosion.)

My understanding is the refueling thing is normally to prevent condensation in the airspaces.  You'd get moisture in the airspaces if the temperature changes a lot between night and day, since the airspace would "breathe" in and out of the vents.  Less airspace means less breathing.  If you're hangared, there would still be the possibility, but less.  I don't know what the evidence is that this is a real, practical issue though...  FWIW, I'm hangared in Oregon and I've never found water in the tanks.

[OR75]

emptying the fuel tanks is messy 

fuel does not fall straight down from the fuel drains

[Bob - S50]

1 hour ago, jaylw314 said:

My understanding is the refueling thing is normally to prevent condensation in the airspaces.  You'd get moisture in the airspaces if the temperature changes a lot between night and day, since the airspace would "breathe" in and out of the vents.  Less airspace means less breathing.  If you're hangared, there would still be the possibility, but less.  I don't know what the evidence is that this is a real, practical issue though...  FWIW, I'm hangared in Oregon and I've never found water in the tanks.

I doubt it is significant.  Otherwise all our tanks would eventually fill with water and that isn't happening.  If it did we could solve the water shortage problem by giving everybody an empty tank that could breath.  We've been filling to 30-35 gallons since we got the plane 5 years ago and I am yet to find any water in the tanks.

[jaylw314]

31 minutes ago, Bob - S50 said:

I doubt it is significant.  Otherwise all our tanks would eventually fill with water and that isn't happening.  If it did we could solve the water shortage problem by giving everybody an empty tank that could breath. 

Heh, actually, that's sort of the idea of water desalination   I agree, though, it's hard to imagine the small amount of air and moisture coming into and out of the fuel tank through the vents will result in significant condensation.  The expansion would have to be more than the volume in the vents, otherwise it would just recycle the air in the vent without bringing more moisture in. 

[pwnel]

7 minutes ago, jaylw314 said:

Heh, actually, that's sort of the idea of water desalination   I agree, though, it's hard to imagine the small amount of air and moisture coming into and out of the fuel tank through the vents will result in significant condensation.  The expansion would have to be more than the volume in the vents, otherwise it would just recycle the air in the vent without bringing more moisture in. 

It seems it's one of those ideas in aviation (as in dietary "science" etc), where the phenomenon might be accurate, but we get the actual impact way wrong.  (Sure, coffee might cause cancer in a very very small number of cases but is it really worth putting notices all over California coffee shops? :-)  Thanks for the replies.

Edited June 13, 2018 by pwnel

[jetdriven]

2 hours ago, Bob - S50 said:

I doubt it is significant.  Otherwise all our tanks would eventually fill with water and that isn't happening.  If it did we could solve the water shortage problem by giving everybody an empty tank that could breath.  We've been filling to 30-35 gallons since we got the plane 5 years ago and I am yet to find any water in the tanks.

Same here. I’ve left it half full, full, and nearly empty and water has never came from the fuel drains in 8 years. And it sometimes rains in the hangar in Houston from the humidity and the plane is wet every morning from condensation. 

[jetdriven]

7 hours ago, N201MKTurbo said:

I

The easiest way is to make up an AN6 hose. take off the cowl and disconnect the fuel line from the firewall and replace it with your hose. Then pump it out with the fuel pump. This was easy with my old M20F because you could just take off the lower side panel. A lot more trouble in the 201.

There’s been a few pilots burn up there Dukes fuel pump emptying tanks this way. It’s a 500$ repair at aeromotors or over a grand at QAA. 

Edited June 14, 2018 by jetdriven

[xcrmckenna]

I’ve pulled 15 gallons out of the plane about five times last summer when it gets in the 100’s. My Airport doesn’t care if I store fuel and the people I rent my hanger from just want it back in the plane after it gets put to bed.

I use a 1/2 hose that’s about six feet long. I manually siphon the fuel out. As long as I don’t drink any it’s a non event.

If it was that dangerous the airport would probably not allow us to fuel our planes.


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[carusoam]

Find the thread where everyone discusses finding moisture in their tanks for any reason...

Nobody ever found measurable water in their tanks from condensation...  Sure it is possible.

Water typically shows up through a few different ways... rain, leaky seals, rusted holes in the mild steal tank necks...

condensation would take some very high moisture content air, followed by sitting in some really chilly air in the hangar...

Balance the risk you take, with the benefit you get...

Handling fuel takes on a lot of risk.  Extra risk if you do it in the hangar...

I only fuel the plane before going flying....  for some reason... 

Always sump the tanks and drain the separator.... just because.

Best regards,

-a-

[skydvrboy]

34 minutes ago, carusoam said:

Water typically shows up through a few different ways... rain, leaky seals, rusted holes in the mild steal tank necks...

Or water contamination in the fuel you just pumped in.  I refueled at a small little airport and got about a half a cup of water out when I sumped my tank.  I was taught to do that before every flight and especially after refueling for this very reason.

[McMooney]

always full, never fly with more than 2 passengers.  Matter of fact, can't even imagine getting 4 people in an E model, think it's physically impossible

[carusoam]

Water and the wrong type of fuels have been delivered to Mooneys before...

It can be challenging to see a small amount of jet fuel...  and a large amount of water....

If the fuel looks like all water, and you aren’t sure what you are looking at... spit into the fuel cup...

The spit should try to sink to the bottom...

If it mixes in... you have a lot of water in the cup... or you may have a lot more alcohol in your saliva than you think... 

Best regards,

-a-

[carusoam]

4 minutes ago, McMooney said:

always full, never fly with more than 2 passengers.  Matter of fact, can't even imagine getting 4 people in an E model, think it's physically impossible

Check in with Bob... @Bob_Belville

Four good looking and normal sized people, photographed... in his M20E.

Could be the engineering background that makes this challenge easier...  Best to be a packaging engineer though... 

Best regards,

-a-

[N201MKTurbo]

3 hours ago, jetdriven said:

There’s been a few pilots burn up there Dukes fuel pump emptying tanks this way. It’s a 500$ repair at aeromotors or over a grand at QAA. 

If the Dukes pump failed emptying a tank, it was a ticking time bomb anyway. Better to fail emptying a tank than when you really need it.

[carusoam]

There are fuel pumps and tanks that are designed to handle this... the construction industry is good for moving diesel in and out of equipment in the field...

Read up on proper grounding if you go in this direction...

Simple errors can be terrible when fuel is involved.

Best regards,

-a-

[jetdriven]

4 hours ago, N201MKTurbo said:

If the Dukes pump failed emptying a tank, it was a ticking time bomb anyway. Better to fail emptying a tank than when you really need it.

I think they are ticking time bomb right out of the overhaul shop.When we first bought our plane I was overseas but the other two owners had to get some landings before they could fly solo.  POH does say fuel pump on for take off and landings and they’re doing taxi back landing so they pretty much left it on the whole time for an hour.  Sometime during that hour of the bearings seized up and the pump stopped working. Motor had amp draw, the motor windings had continuity, and the circuit breaker switch would not trip but the pump was not running. Sometime during that hour of the bearings either seized up or the nylon vanes inside   Disintegrated, but either way like fresh 900$ Dukes factory overhaul pump was toast after one flight.  After a few weeks of this thing being gone and still not returned to us and  ended up calling the Dukes factory out in California and spent a whole day messing around with this.i learned they were considering not warranting the pump because of abuse. I asked what kind of abuse is leaving a pump on for an hour with the engine running and they said it’s not made for that. I think its a garbage design personally. 

Edited June 14, 2018 by jetdriven

[Bob_Belville]

7 hours ago, carusoam said:

Check in with Bob... @Bob_Belville

Four good looking and normal sized people, photographed... in his M20E.

Could be the engineering background that makes this challenge easier...  Best to be a packaging engineer though... 

Best regards,

-a-

Lynn Mace A&P/IA, sitting behind me, is over 200#, Margo Hull, the blond sitting behind Nancy, is taller than I am. (Jolie brought her own headset, the plane has 4 David Clarks and XM radio.) 

@McMooney sure glad I didn't know that it was impossible to fit adults into the back seat of an E.