I ran one dry on my base leg during my wife's first ever ride in my plane. She knew nothing of the issue but I was very upset. Was the longest restart I've ever had..... talk about nervous.
No fuel at my airport?!
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I ran one dry on my base leg during my wife's first ever ride in my plane. She knew nothing of the issue but I was very upset. Was the longest restart I've ever had..... talk about nervous.
My 310 with 470s is much the same.
The other advantage of running a tank dry is that "unusable fuel" for planning purposes becomes useable. Say you have two tanks that each have 2 gallons of unusuable fuel. When you run one tank dry in level cruise, that 2 gallons gets used and now you only have 2 gallons of unusable fuel, rather than 4. It's a small difference, but 2 gallons of fuel might make the difference if stuff really hits.
JHW
En-Route
No.
Unusable means that when the tank is "dry" your 2 gal is still in that tank.
For planning purposes, yes.
But it is not uncommon to be able to still manage to burn that fuel in level flight. Unusuable fuel is based on fuel that may not be accessed in normal pitch up or pitch down flight. So being able to burn this fuel is like getting 2 extra unplanned gallons of fuel.
dell30rb
Final Approach
In the old red swift I like to start on the tip tanks and alternate between till they are dry, then go to the main tank.
Well, with passengers I would run them down till the gauge reads 0.5 gallons left, knowing from experience that was actually an accurate reading and I was only a few minutes from running out of fuel.
On the new (pending pre-buy) Swift the continental fuel injection is constantly returning unused fuel to the main tank. So if I started on my aux tanks, after a few minutes the return would fill up the main tank and fuel would go out the vent line. Some kind of shuffling between tanks will have to be used. Haven't figured out what i'll do yet.
Well, with passengers I would run them down till the gauge reads 0.5 gallons left, knowing from experience that was actually an accurate reading and I was only a few minutes from running out of fuel.
On the new (pending pre-buy) Swift the continental fuel injection is constantly returning unused fuel to the main tank. So if I started on my aux tanks, after a few minutes the return would fill up the main tank and fuel would go out the vent line. Some kind of shuffling between tanks will have to be used. Haven't figured out what i'll do yet.
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That's not how it works with my flow meter vs what I pump in, it's always within half a gallon accounting that the unusable fuel was still in the tank.
bnt83
Final Approach
All I know is, when I drain the gas via carburetor hose, I can only get about 2 cups from the tank sump which is placarded .5 gallons unusable. From "drained and sumped" to full its about 1.5 gallons more than placarded capacity.
Dead Stick
Line Up and Wait
So, if you need to dip into your reserves, your reserves are going to be spread out over 4 tanks? Looking back on that, won't that seem pretty foolish? Oh well, maybe not as long as you're proposing to violate the STC by running fuel with ethanol.
That sounds similar to the 337s fuel system. Fuel is drawn at a rate twice of what's necessary to run the engine. The excess fuel gets returned to the main tank. You have to run about an hour off of each main to make room before you run the Aux tanks. You then run the Aux takes dry (they drain twice as quickly as you would think) and then run the rest of the flight with each engine on its principal tank.
No it doesn't. It means it's not reliably obtainable. You can burn the unusable fuel in some circumstances.
I don't know if it's because of unusuable fuel being burned or the tanks being overfilled (there's no real indication where the top is and it changes based on whether the plane is sitting level or not) but I get more than 20 in and out of my tips.
Shepherd
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We had an aviation themed Vacation Bible School at the church, so I borrowed a Cessna 152 (that hadn't flown in years) and brought it to the church and set it up on the lawn.
We are only 2.5 miles from 44N, so it's a quick trip with the wings off on a trailer. On the second day of VBS, the utility company shows up and says they are going to do some branch trimming, could we move the airplane? There wasn't enough room to move it back, so 4 of us pushed it out onto the street so we could move it a hundred yards down and back onto the property. We got lots of attention, and the opportunity for humor was WAAYYY over the top. Lots of witty repartee, but my 2 favorite comments:
1. (to a non-aviation person) "We are trying to jump start it by pushing it".
2. (to a retired CFI ) "I didn't have enough fuel to get to the airport, so I landed on the street and we are pushing it until we get close enough to fly it back."
The CFI laughed like crazy, gave us a "Good job!" and drove off. About an hour later he comes back with some pictures and a newspaper story from 1941. It seems he had run nearly out of fuel in a J-3 Cub, landed on the road and been towed almost back to the old Wappingers airport. He climbed back in, took off, hopped over the fence and landed it.
Just goes to show there is nothing new under the sun.
We are only 2.5 miles from 44N, so it's a quick trip with the wings off on a trailer. On the second day of VBS, the utility company shows up and says they are going to do some branch trimming, could we move the airplane? There wasn't enough room to move it back, so 4 of us pushed it out onto the street so we could move it a hundred yards down and back onto the property. We got lots of attention, and the opportunity for humor was WAAYYY over the top. Lots of witty repartee, but my 2 favorite comments:
1. (to a non-aviation person) "We are trying to jump start it by pushing it".
2. (to a retired CFI ) "I didn't have enough fuel to get to the airport, so I landed on the street and we are pushing it until we get close enough to fly it back."
The CFI laughed like crazy, gave us a "Good job!" and drove off. About an hour later he comes back with some pictures and a newspaper story from 1941. It seems he had run nearly out of fuel in a J-3 Cub, landed on the road and been towed almost back to the old Wappingers airport. He climbed back in, took off, hopped over the fence and landed it.
Just goes to show there is nothing new under the sun.
JHW
En-Route
neither one of those have anything to do with unusable fuel
and it's a moot pouint. You get what you get out of that tank until the engine stope, then you switch to the next tank.
JHW
En-Route
that's a given, there is no fixed amount that is always there every time. My point was that the poster believes there is some fixed quantity of fuel which a book does not allow him to use but which is readily obtainable when he chooses to use it, which is a fundamentally flawed understanding.
I never said it was readily obtainable when I chose to use it.
Assume you have an aircraft with two 22 gallon tanks, both of which have only 20 gallons usable.
You have a fuel flow meter, and have been keeping good notes on how much fuel you've used in both tanks, switching every 30 minutes. You now calculate that you're coming up on using 20 gallons from the left tank.
Do you switch now, or do you wait for it to run dry?
If you wait for it to run dry, you may start to see the tank empty at 20 gallons, but it might burn a gallon or so more. You are now going into the unusable portion of that tank. Let's say it does burn those two extra unusuable gallons--that's two gallons of usable fuel you're NOT burning from the right tank.
If you have more tanks, the same process can be repeated. It's OK to run a tank dry at altitude. In the process of running it dry, you MAY recover some of that unusable fuel. If you do, that means MORE fuel in the remaining tank when it comes time to land.
One should never PLAN on being able to use unusable fuel, but all things equal, I'd rather land with 10 total gallons in one tank (8 gal useable), than two tanks with five gallons each (6 gal total usable).
vdehart
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I just don't imagine I'd ever be comfortable purposefully waiting for the engine to sputter in flight. Too much pucker factor for my taste. I'll run it reasonably close, but right until it's sucking air, no thanks...
If you have fuel in another tank, what is it you are afraid of?
3393RP
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Are you saying that mixing 1/2 gallon of ethanol (10% of the five gallons of mogas) with twenty gallons of 100LL along with the 4 1/2 gallons of mogas which results in a 4% concentration of ethanol in the airplane until it can be filled with twenty or so more gallons of 100LL an hour after the ethanol was introduced further reducing the concentration to less than 2% won't cause all of the hoses and o-rings and carburetor parts to immediately swell and crumble and other bad things causing the aircraft to fall out of the sky?
That's an irresponsible rush to judgement.
Doggtyred
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Know your fuel burn. Know your fuel state. And when you ggt close to exhaustion you pay very very close attention to your engine and at the very first sign of any stumble you consider that "dry" and switch tanks.
Fuel pump on when you switch if it makes you feel better.
As long as the prop is spinning, re-introducing fuel flow makes it start "running" again.
Doggtyred
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Are you saying that mixing 1/2 gallon of ethanol (10% of the five gallons of mogas) with twenty gallons of 100LL along with the 4 1/2 gallons of mogas which results in a 4% concentration of ethanol in the airplane until it can be filled with twenty or so more gallons of 100LL an hour after the ethanol was introduced further reducing the concentration to less than 2% won't cause all of the hoses and o-rings and carburetor parts to immediately swell and crumble and other bad things causing the aircraft to fall out of the sky?
That's an irresponsible rush to judgement.
Are you saying it wont? Where is the data supporting or not supporting your conclusions?
Are you saying that mixing 1/2 gallon of ethanol (10% of the five gallons of mogas) with twenty gallons of 100LL along with the 4 1/2 gallons of mogas which results in a 4% concentration of ethanol in the airplane until it can be filled with twenty or so more gallons of 100LL an hour after the ethanol was introduced further reducing the concentration to less than 2% won't cause all of the hoses and o-rings and carburetor parts to immediately swell and crumble and other bad things causing the aircraft to fall out of the sky?
That's an irresponsible rush to judgement.
It's actually quite surprising how small a concentration of alcohol can swell the wrong types of hoses, o-rings, and other polymer parts. Will it cause the plane to fall out of the sky? Meh, probably not unless your fuel line is already old and past its 20 year life span, then it may swell shut or come apart internally blocking your fuel flow, then things get interesting. What's even more interesting is the few thousand dollars it will cost replacing the hoses, rebuilding the fuel valve, and changing out leaky seals. If you are lucky you have a carb and it costs $500, if you have FI it's $1500.
It's easy enough to break the alcohol off of gasoline and get rid of it.
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Are you saying that mixing 1/2 gallon of ethanol (10% of the five gallons of mogas) with twenty gallons of 100LL along with the 4 1/2 gallons of mogas which results in a 4% concentration of ethanol in the airplane until it can be filled with twenty or so more gallons of 100LL an hour after the ethanol was introduced further reducing the concentration to less than 2% won't cause all of the hoses and o-rings and carburetor parts to immediately swell and crumble and other bad things causing the aircraft to fall out of the sky?
That's an irresponsible rush to judgement.
Immediately? Probably not.
I once had a 1969 Renault R-10 sedan. 4 wheel disc brakes. 48 roaring horse power. The brake fluid was just a smidgen low. Even though the cap said SAE-40, I (at 18) figured brake fluid was brake fluid. I put just about a tablespoon in the reservoir. What I didn't know was that all the seals in the brake system were neoprene. And petroleum based brake fluid (this was 1977) eats neoprene. Over the course of the next 2 months I had to rebuild the entire brake system. It's not ethanol in a fuel system-but it is a very little bit of contaminate in a fluid filled system.
What happens immediately is not a problem. What happens over time, event with a little bit can be. I don't know if it will be. If I had to bet, I'd bet you don't either.
John
Umm, I'm sorry but I disagree. The guys who are PROPENENTS of running ethanol have had some pretty spectacular failures with O-320 carbs and it didn't take very much run time. If they don't think that ethanol blends are a good idea, I'm not sure I would.
We had a Navion crash severely injuring the former president of the American Navion Society. No mogas STC for Navions, but those who were on the seen suspect highly that the stuff leaking out of the tank at the crash site was indeed the wrong color.