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Anyone ever run a tank dry in flight...on purpose?

B

BrianNC

Well Known Member
What do you think?

Pelican's Perch #7: Run That Fuel Tank Dry!
John Deakin

AVweb's John Deakin takes aim at yet another OWT (Old Wive's Tale). While running a fuel tank dry in your recip powered plane may serve to increase your heart rate, John explains why it's not such a bad thing at all, and it is probably a really good idea for most of us. In fact, John explains why it's one of the first things you ought to do with a new plane and how it could save your life someday.

http://www.avweb.com/news/pelican/182044-1.html
 
It's a non-event.

I ran each of my tanks dry (different flights) in order to do the fuel pick up modification recommended by Van's Service Bulletin. It beats trying to drain the tanks on the ground and it gave me a good idea of what to expect should it ever happen again. Once my fuel indicator read "zero" the engine continued to run for about 5 to 10 minutes and the first indication of impending fuel starvation was a gradual decrease in fuel pressure. Once the engine started to lose power I switched to the full tank and power came right back up in just a few seconds. Didn't even need to turn on the boost pump.
I have also shut the engine down with the mixture control in order to ascertain best glide speed with the engine windmilling. Throwing the mixture back to rich gets power back almost immediately.
I'm not going to suggest that everyone do as I do, but I'm here to tell you that shutting the engine down in flight is a non-event.
 
BrianNC said:
What do you think?...
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I used to do it routinely in the Pacer with the auxiliary tank under the back seat.

I have only done it once in my RV. It was for some purpose that I can't even remember now. Possibly it was to time how long the engine would run, in level flight, after the gauge registered empty. I do remember that you don't have to wait for the engine to stop. It starts losing power first then a simple tank change restores things to normal.
 
Noise and the electric pump

I haven't done this and don't plan to but if you left the electric pump on the sound of the pump would get louder as it ran out of fuel. I imagine that's not too good for the electric pump, but at least you'd have another early warning.

I've gone as low as 2 gal and then the wife starts tapping the fuel gauge, telling me it's time.
 
Yep....Done it...Non-Event

My RV has extended range tanks (29 gal/ea) and after I bought it, I wanted to accomplish 3 items.
1. Get a reading on unusable fuel.
2. Verify that the tank indeed did hold 29 Gal.
3. Calibrate a fuel stick.
The fuel pressure began to decay rapidly, and shortly thereafter power was lost. Switched tanks and power was restored within seconds.
Non-event!
 
I posted this on the AOPA forum also and it appears to be quite common. I had never heard of it in all my training or anywhere else until I read that article a few years ago. They all say it's the only way for certain to know exactly how much fuel you have, and a lot of them do it all the time on long x-countries where you have the time to run a whole tank dry. Some like having all their reserves in one tank instead of it being split in half between two.
 
Yes while doing endurance testing. I wanted to know how long the plane would run after the red alarm led illuminated on the EI fuel guage. The answer was 17 minutes until the fire went out. There was no fluxuation in fuel pressure that was noticable before the power loss and the engine came to life as suddenly as it died after switching tanks. It was really no big deal, but then my plane is carbed, not injected.

After doing this test the tank took 18.1 gallons to bring it up to the bottom of the filler neck. Van's claim is 18 gallons per tank.

Also, prior to the first engine start I put a known quantity of fuel in the tanks and then disconnnected the fuel line from the carb. Using the electric fuel pump to drain the tanks it looked like all but about a pint is usable with the pick up tubes installed per the plans.
 
Been there, done that.

I wanted to recalibrate my fuel tanks, so I was intending to run the tank low so that I would not need to drain much out. Both times (two tanks, different flights), I missed guess and ran them dry. I didn't notice any change until the engine didn't have any fuel and sounded funny.:eek:
I switched tanks while looking for a place to land. The engine started making power right away. I didn't need to turn on the fuel pump.
After the flight I downloaded flight data and during the 3 seconds the engine RPM dropped from 2350 to 1800 and I lost 100 ft in alt. I can't remember the speed change, but it wasn't much.

Kent
 
Yes

And like the others have related, it was a non event. I was very nervous about it the first time, not as much the second. Hasn't been a 3rd due to lack of need, but it will come.

My wife was more nervous than I was. Having her on board is better than any possible fuel alarm.
 
I had a BMA EFIS 1 that was calibrated wrong. Ran one tank out, but it said I had 7 gallons left. :eek: I switched to the other tank, and it said it said I had 10 gallons left. :cool: I decided to land at the nearest airport and take on some more just incase. :D

It's really a non-event. The fuel pressure drops right before the engine starts to sputter. Switch tanks and she fires right up.
 
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I've done it a couple of times on long XCs. No biggie in my book - I plan for it and do it at altitude. I'd rather land with one tank having 8 gals than two tanks with four.
 
BrianNC said:
Some like having all their reserves in one tank instead of it being split in half between two.
Click to expand...

I have friends who say they do that. Run the tanks dry and therefore you know there is no gas there so you never need to go back to that tank.
 
Did it just the other day...

Ross did it to empty a tank before taking it off to repair a weeping rivet. 3,000' while orbiting a runway.

'Nothin' burger' as he would say....
 
Haven't done this yet on my RV6, but I did it tons of times on my 4-tank Cherokee 235. Some intentional, some not (no wife-alarm).

The Cherokee would simply go f-f-f-f-f-f-f-f-f in a heartbeat. If I watched the pressure gage, yes it would drop to zero. But there was NO WARNING from the carbureted engine (O-540). Full power to zip in a half-second.

Plane kept on going, and from cruise to best-glide is many, many seconds even in the old sluggish Cherokee airframe. Without the electric pump on, it would take up to 20 seconds for the lines to re-fill and the carb to fill up enough to make more power. Sounds like a lot, but it would only be an issue on short final (low and slow). Watch that GUMP checklist for sure.

One major hint to all: If you have a REAL engine-out, and a CS prop, PULL THAT PROP. You wouldn't believe the improvement in glide ratio. Try this with a Garmin GPS that shows your glide ratio and see, it's nearly a 20% improvement.
 
I had a Navion Rangemaster with fuel injection and tip tanks with no gauges. I would run off the tips in cruise and often ran them dry. Switch tanks, back in business.

Only problem was with the passengers.

Ken
 
I avoid it but I have a plan to manage it methodically

First of all the guy who's engine stopped for lack of fuel and there was no change in the fuel pressure indication - something is wrong with your fuel pressure system. I have four tanks on my RV-6A and the expected fuel burn time out of each is .8hr, 1.8hr, 1.8hr and .8hr from tip to tip respectively. I do not like glider flight in my RV-6A but I like to fly long distances. My sequence is .5hr, .5hr, .5hr, 1 hr, .3 hr or drop in fuel pressure, .3 hr or drop in fuel pressure, 1hr, .5hr, .3hr or drop in fuel pressure, .3hr or drop in fuel pressure. At this point I am down to what ever small amount is in the tanks that were still providing fuel when I switched from them the last time. I flight plan with an hour reserve minimum but there have been times when conditions are such that the reserve is eaten into to the point of four red lights (2 gallons - .2hr - left at illumination) at landing (after a total electrical failure in flight from Panama City Beach, Florida to Fayetteville Arkansas a couple of years ago). Handheld GPS 90 and non electrical gauges worked fine.

Bob Axsom
 
Let's think about this

plehrke said:
I have friends who say they do that. Run the tanks dry and therefore you know there is no gas there so you never need to go back to that tank.
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I think we all know that running a tank dry is a non event if planned for and easily corrected if done by mistake. That is assuming you have another tank with gas in it. What I think the question here is should we do it on purpose.

I routinely fly a trip that leaves me with 6 to 8 gallons of fuel remaining. My SOP is to takeoff on the left tank and climb to about 12k and then switch to the right tank. I note the time and the fuel flow indicator's guess at remaining fuel on board. Then using the indicated fuel flow I calculate how long I can run on the right tank. When the gauge reads zero, I know I have about 13-14 minutes of fuel remaining in the right tank. As my predicted time approaches I start watching the fuel pressure gauge. I've found that if I turn on the boost pump at the first indication of fluctuating fuel press and then quickly switch tanks I can keep going without the engine missing a beat. Of course, every once in a while I screw this up and get startled when the engine quits but the recovery procedure is the same and relight is immediate. I do this because my fear is a delay or divert and now my reserve is split between two tanks and I'm afraid of fuel exhaustion on approach or go around. It would be a hustle to get the fuel switched and the motor restarted while low and slow. On the other hand. if the left tank fails to feed anytime after I've emptied the right tank, I'm screwed. So maybe it is better to leave 10 minutes of fuel in the right tank. I've been thinking about this a lot and I can't completely convince myself either way is right. What do ya'll think?
 
cguarino said:
On the other hand. if the left tank fails to feed anytime after I've emptied the right tank, I'm screwed. So maybe it is better to leave 10 minutes of fuel in the right tank. I've been thinking about this a lot and I can't completely convince myself either way is right. What do ya'll think?
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That is exactly why I leave a couple gallons in the tank when I change over. If the new tank does not feed I have enough fuel switch back to the original tank to get to a landing spot.
 
When we hauled freight in the Twin Beech we dried the aux tanks out every nite. If it was dark you would see the low pressure lites and I would switch before it quit. In the daytime you had to watch the gauge really close to catch it. Looking out the windows for traffic is a better idea.

It is not a big deal, but when it quits, be calm, reduce the throttle, switch tanks, slowly, don't break the handle off in a rush, turn on the boost pump and slowly advance the power. DO NOT switch tanks and turn on the boost pump with the power at cruise!!! you will get a huge surge, especially in a C/S airplane.

If the mixture is really thin, in some airplanes you have to advance the mixture to get them to catch.

It is not an emergency, don't make it one!

My wife does not approve of this procedure:eek:

Tailwinds
Doug Rozendaal
 
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I have a count down timer........... and I switch tanks every 45 minutes. It keeps the wings level, gives me something to do and draws my attention to my remaining fuel. I never run a tank dry during x-country.

Anyone who crashes a low wing aircraft due to fuel starvation, has run out of fuel at least twice.................
 
Used to do it regularly in Cessna 402 carrying mail in my early career. Burn the aux tanks dry and switch to mains. This could be counted on to give you a shot of adrenaline at 0400 in the morning if your attention was wandering a bit.^_^

Did it on my old Bonanza when needing max range. 45 minutes out of the left main, switch to aux tanks and run them till empty. Aux tanks put what the engine did not use back into the left main. Switch back to the left main until it was empty. Then I had a right main that was completely full. With a good fuel totalizer, I had a very accurate time remaining at that point. I did it enough times to have a pretty accurate estimate on time til the aux tanks and the left main would run dry. Watched the fuel pressure and it would begin to fluctuate. Switch right then, and the engine never missed a beat.

Did it during phase one on my RV-10 circling overhead an uncontrolled airport. Did one wing, landed and fueled to see how much unusable was left. Repeat on the other wing. Also wanted to check controllability with max imbalance. No problems.

As Doug R. said, don't make it an emergency.
 
dmaib said:
Used to do it regularly in Cessna 402 carrying mail in my early career. Burn the aux tanks dry and switch to mains. This could be counted on to give you a shot of adrenaline at 0400 in the morning if your attention was wandering a bit.^_^

Did it on my old Bonanza when needing max range. 45 minutes out of the left main, switch to aux tanks and run them till empty. Aux tanks put what the engine did not use back into the left main. Switch back to the left main until it was empty. Then I had a right main that was completely full. With a good fuel totalizer, I had a very accurate time remaining at that point. I did it enough times to have a pretty accurate estimate on time til the aux tanks and the left main would run dry. Watched the fuel pressure and it would begin to fluctuate. Switch right then, and the engine never missed a beat.

Did it during phase one on my RV-10 circling overhead an uncontrolled airport. Did one wing, landed and fueled to see how much unusable was left. Repeat on the other wing. Also wanted to check controllability with max imbalance. No problems.

As Doug R. said, don't make it an emergency.
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So how much was there unusable in your tanks?
 
fuel

Each time we got a new airplane (Mooney, Commanche 260B, Lance) we flew each tank dry (while high over good airport) and restarted as described. Correlated fuel gauge readings with starvation moment, quantity by fill etc and then could compute/gauge from that point on to leave at most .5 gal in each tank but have no engine stoppage. Restart was always easy. Agree with comments about retarding throttle and advancing slowly to avoid surge with CS prop. Almost every report notes easy restart, but I would hate to have the first failure occur over unsuitable terrain, so don't run tanks dry on X-C unless over a good landing spot. Bill
 
I'm surprised.....

.....that suddenly chilling the cylinder heads hasn't been mentioned. When you go from cruise power to zero, the thermal shock has to be hard on cylinders and also the hot exhaust system.

I can understand doing it once to check fuel quantities but not as a habit.

Years ago I read about a turbo-charged Bonanza that ran a tank dry near 'Vegas in the winter. It shucked a turbo blade and the engine ingested it...not pretty.

Be careful,
 
pierre smith said:
.....that suddenly chilling the cylinder heads hasn't been mentioned. When you go from cruise power to zero, the thermal shock has to be hard on cylinders and also the hot exhaust system.

I can understand doing it once to check fuel quantities but not as a habit.

Years ago I read about a turbo-charged Bonanza that ran a tank dry near 'Vegas in the winter. It shucked a turbo blade and the engine ingested it...not pretty.

Be careful,
Click to expand...

This from the article discusses that:

Shock Cooling?

I'm beginning to think this business of "shock cooling" is perhaps the worst of the "modern" OWTs around, but it's one that sounds very reasonable at first glance. I'm still not utterly certain myself. But consider, which airplanes get the longest TBO? Why, it's TRAINERS! They CONSTANTLY jam the power on, and yank it off, many times an hour, all day, every day. No regard or thought of temperature control, at all. If shock cooling is so bad, why do they last so long? Does anyone know how many hours Bob Hoover gets from his Shrike engines? They go from full power to a full stop (feathered) with NO interval, and right back to full power again. I've tried to get to him to ask, but he's always mobbed. Does anyone know?

Now please, I'm not advocating abuse of any precision machinery, here! I prefer gentle engine management, it's just good airmanship. But "shock cooling" may be a non-issue.

In any event, if properly done, running a tank dry does NOT cause "shock cooling" at all! Once the pilot knows what he is doing, he should know precisely when the tank will run dry, and will detect the early signs well before the engine is affected (fuel pressure, mostly). Even after the engine begins to falter, there is time to change tanks and get things back to normal before the CHTs drop. We now know this, with the modern digital engine monitors. The EGTs do drop a couple of units, but they recover very quickly, so even turbocharged engines shouldn't have a problem. I would be more careful with a turbo, however, because other issues arise, like surging, bootstrapping, etc.
 
I've read all the posts to this thread and I've not seen mentioned once that all the reasons folks are running their tanks dry, can be safely accomplished on the ground! I've never run a tank dry in the air but I know exactly to the tenth of a gallon how much usable fuel/unusable fuel I have and how much is in my tanks. Granted it takes a fuel totalizer to know this and if accurately calibrated (on the ground) it is very accurate.

Sorry, but I don't need to stick my hand over a burning candle to know it's hot and it will hurt.
 
f1rocket said:
I've read all the posts to this thread and I've not seen mentioned once that all the reasons folks are running their tanks dry, can be safely accomplished on the ground! I've never run a tank dry in the air but I know exactly to the tenth of a gallon how much usable fuel/unusable fuel I have and how much is in my tanks. Granted it takes a fuel totalizer to know this and if accurately calibrated (on the ground) it is very accurate.

Sorry, but I don't need to stick my hand over a burning candle to know it's hot and it will hurt.
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In the thread over at AOPA many say they do it because it is much easier than draining a tank. But they don't do it only for that. Many do it regularly on long trips to maximize range and actually consider it an act of safety since you have totally drained that tank, now know exactly how much fuel you have left in the remaining tank, and all remaining fuel is in the same tank. And now you know you never have to go back to the same tank.

Did you read the article? :)
 
BrianNC said:
Did you read the article? :)
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No, I don't need to.;) I can maximize my range without doing so and I know exactly to the tenth of a gallon how much fuel I have on board at all times. I just don't see the point of doing it.

I should add that my engine is fuel injected and I worry about getting it started again, although I suspect if I just pull the mixture and throttle back it will fire right back up.
 
I agree with the the thought you should not do it as SOP day in day out.

For whatever reason current tank fails to feed or stops feeding.

Option to switch back to the other tank is pointless if it's dry.

Why throw out your options?
 
Can't read it without being a member. Specifically to RV's there have been fuel issues with the vent line causing a failure to feed. Flop tubes falling off inside the tank significantly reducing the usable fuel and the standard pickup falling off (aka Service Bulletin No. SB 06-2-23).

Does the AOPA thread your referencing discuss RV's or just light GA aircraft in general?
 
asav8tor said:
Can't read it without being a member. Specifically to RV's there have been fuel issues with the vent line causing a failure to feed. Flop tubes falling off inside the tank significantly reducing the usable fuel and the standard pickup falling off (aka Service Bulletin No. SB 06-2-23).

Does the AOPA thread your referencing discuss RV's or just light GA aircraft in general?
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In general. But this is one thing I was wondering about. Here is the FAA certification rule in this area. It is a requirement that in a normally aspirated airplane that if you exhaust fuel in a tank, that the airplane must restart within 10 seconds after switching to a full tank in level flight. Do experimentals have to abide by that rule?

FAR 23.955(e) Multiple fuel tanks. For reciprocating engines that are supplied with fuel from more than one tank, if engine power loss becomes apparent due to fuel depletion from the tank selected, it must be possible after switching to any full tank, in level flight, to obtain 75 percent maximum continuous power on that engine in not more than -

(1) 10 seconds for naturally aspirated single engine airplanes;

(2) 20 seconds for turbocharged single engine airplanes, provided that 75 percent maximum continuous naturally aspirated power is regained within 10 seconds; or

(3) 20 seconds for multiengine airplanes.

FAR 25.951(a) Each fuel system must be constructed and arranged to ensure a flow of fuel at a rate and pressure established for proper engine and auxiliary power unit functioning under each likely operating condition, including any maneuver for which certification is requested and during which the engine or auxiliary power unit is permitted to be in operation.


(b) Each fuel system must be arranged so that any air which is introduced into the system will not result in -

(1) Power interruption for more than 20 seconds for reciprocating engines; or

(2) Flameout for turbine engines.
 
Since everyone is free to plumb however they see fit, and the FARs you reference are not part of the certification process for each build/test phase under the experimental certificate, I believe the answer is.................... no.

6,000+ RVs. 6,000+ different plumbing jobs.
 
asav8tor said:
Since everyone is free to plumb however they see fit, and the FARs you reference are not part of the certification process for each build/test phase under the experimental certificate, I believe the answer is.................... no.

6,000+ RVs. 6,000+ different plumbing jobs.
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Thanks. But from these posts some with Vans do it a SOP. I supposed there is a way to insure that will happen. But I know nothing about building fuel systems since I haven't built a plan yet.
 
fuel

Each time we got a new airplane (Mooney, Commanche 260B, Lance) we flew each tank dry (while high over good airport) and restarted as described. Correlated fuel gauge readings with starvation moment, quantity by fill etc and then could compute/gauge from that point on to leave at most .5 gal in each tank but have no engine stoppage. Restart was always easy during testing. Agree with comments about retarding throttle and advancing slowly to avoid surge with CS prop. Almost every report notes easy restart, but I would hate to have the first failure occur over unsuitable terrain, so I don't run tanks dry on X-C unless over a good landing spot. Bill
 
Running a tank dry with FI

Understanding the operation of each fuel metering system should used to make a determination along with documented procedures for running a tank dry in flight (intentional or otherwise). Personally since I am a low time pilot and fly a plane that basically gives you around 30 seconds to pick out a place to land if your 2500? AGL and it gets quiet, I don?t mess with seeing how much fuel I can get out of the tank. But in any case since I design and manufacture fuel injection systems that many of you RV pilots use consider the following:

The Bendix /Precision and Airflow Performance fuel injection systems are non-returning systems. The electric boost pump whether it?s AFP or Weldon or whatever bypasses internally or has a pump loop (AFP) back to the inlet to the pump. In the fuel metering system there is a flow divider (spider), the opening pressure is typically 1.5 to 2.5 PSI (some of the new Cessna flow dividers open at 4 PSI). Assume that there is no fuel in the system at all. In order for the boost pump to pick up fuel it would have to generate 1.5 to 2.5 PSI in air pressure to open the flow divider so that the column of air in the system before and after the boost pump can be displaced and the pump can pick up fuel. How long will this take to accomplish? Don?t know. But if the pump can?t generate the required air pressure to open the flow divider to get rid of the air, it will churn away until the pump burns up or you run out of altitude. Now typically in a ?run the tank dry? situation there is some residual fuel in the system and the engine driven pump is still turning. The fuel in the boost pump will allow the boost pump to pump better thus building pressure faster and the engine driven pump aids in increasing the pressure ratio across the boost pump so it can pick up fuel quicker. So in actuality it may be a non-issue as some of you pointed out. With a carburetor, when the float bowl empties, the float drops and the needle opens up the seat wide open allowing no restriction for the pump to push fuel into the system, not so with fuel injection. A doubt that you would pull the purge valve in this situation to get fuel back into the system faster (kind of like putting the mixture in ICO on a Continental system to get the system purged faster) if this type of situation arose in flight. But that would allow the pumps to pick up fuel faster as the fuel bypasses the flow divider so there?s less pressure for the pumps to generate to displace the air.

I?m not condoning that this practice is acceptable or not, only that you understand the operation of the fuel metering system. Anyway this is something to consider when determining if the last drop of fuel needs to be used before switching fuel tanks during flight.

Don
 
Hey, Don, just as a data point for you - I've done it with one of your AFP systems on my airplane. I did it in the testing phase to determine usable fuel and test the accuracy of my fuel gauges (turns out they are accurate to 0.1 gal). I switched the tank when fuel pressure dropped and the engine sputtered - it fired right back up on the other tank.

Cheers,
 
That's great inforrmation to have Don regarding the purge valve. I will add that to my restart procedures in my POH.

Just another reason not to mess with running your tanks dry! (Whether you've read the AOPA forum or not!):cool:
 
I have run a tank dry 4-6 times. Initially it was to determine usable fuel. Once I did it with another pilot so he could learn from the experience.

All events were over an airport. I do not run tanks dry during normal flights. Assuming that I always want eight gallons or so upon landing, I prefer to have some fuel in both tanks just in case one tank has a problem. Low chance of happening but it costs nothing to keep usable fuel in both tanks.

My plane has adequate range using this concept.

I do have a fuel totalizer so I know accurately how much fuel I have.
 
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f1rocket said:
Just another reason not to mess with running your tanks dry! (Whether you've read the AOPA forum or not!):cool:
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Well there are many, many, pilots that would disagree with you that do it as SOP on long trips and have documented the benefits and the safety reasons for it. You really ought to read the article in the original post. :)
 
asav8tor said:
That's what I thought. :rolleyes:
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I have not been pointing to my experience but to that of many, many, others. This is about learning. Not dismissing something outright because we don't agree with it or understand it.

Everyone that has done it understands the reasons behind it. All the naysayers basically have not tried it nor do they want to. It's what they think about it but with no practical experience. If one is not comfortable with it don't do it. But to make definitive statements against it when so many do it regularly and attest to the practicability and safety is pretty closed minded. To each his own.
 
asav8tor said:
Since everyone is free to plumb however they see fit, and the FARs you reference are not part of the certification process for each build/test phase under the experimental certificate, I believe the answer is.................... no.

6,000+ RVs. 6,000+ different plumbing jobs.
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Brian,

As one of the Tech Advisors in the Charlotte EAA chapter, if you presented me with an RV that had a non-standard fuel system, I would document it on the inspection form and let you decided to correct it or not.

In fact, I did the same on a SuperCub replica a few weeks ago. A week after my visit the guy called to tell me he was redoing all of his fuel lines.

I would say that most RV's have a fuel system as recommended by Van's but there are a LOT out there that have done something different.

We are lucky in that Van's makes a recommendation. Some kits do not; they leave the fuel system design up to the builder. Some time with less than optimal results.
 
N941WR said:
Brian,

As one of the Tech Advisors in the Charlotte EAA chapter, if you presented me with an RV that had a non-standard fuel system, I would document it on the inspection form and let you decided to correct it or not.

In fact, I did the same on a SuperCub replica a few weeks ago. A week after my visit the guy called to tell me he was redoing all of his fuel lines.

I would say that most RV's have a fuel system as recommended by Van's but there are a LOT out there that have done something different.

We are lucky in that Van's makes a recommendation. Some kits do not; they leave the fuel system design up to the builder. Some time with less than optimal results.
Click to expand...

I understand. I'm just talking all things being equal. I can see where with an experimental it is a lot different as opposed to a certified airplane where they are required to start back up in a short time after fuel exhaustion of one tank.
 
BrianNC said:
Well there are many, many, pilots that would disagree with you that do it as SOP on long trips and have documented the benefits and the safety reasons for it. You really ought to read the article in the original post. :)
Click to expand...

Brian,

I really do intend to. Although I have my reservations about doing it myself, I do not have a problem with others who choose to do so. I'll go back and read the article and see if it gives me reasons to reconsider my position. Thanks for the learning opportunity.
 
On fumes...

As I crossed the coast of France and turned up the Seinne, the French countryside slipping beneath the Spirit's wings I was contemplating LeBourget and somehow finding Terra Firma after thirty three hours aloft. Reality sank in when my up to this point reliable Wright Whirlwind suddenly was silent. Did I miscalculate, what have I done? I suddenly realized I had run tank 4 dry and switched to a tank with no fuel. Switch to a tank with fuel in it and let's go to Paris!

Charles Lindbergh
Spirit of St Louis

Brian,

If you never run a tank dry inflight, how do you verify the accuracy of the gauge? During testing on all three of my airplanes I built I tested the accuracy of the gauges at a safe altitude by running a tank dry. It's a non-event.

The Rocket with Bendix FI takes a bit more time to get going but presents several very useful warnings for future reference. It has a very accurate automotive-type FP gauge. The fuel pressure drops in 2 PSI increments for 5 seconds prior to flameout. If properly noted you can watch the FP gauge and switch tanks, switch on boost pump and prevent flameout while exhausting every ounce of fuel from the tank, and verifying the accuracy of the gauge. It also gives you a useful time frame for engine restarts in flight. A fuel pressure gauge was installed on the Spirit as Lindbergh used the same tank-dry technique for exhausting every drop of his 425 gallons of fuel, every airplane should have one.

In a carbureted RV equipped with a FF gauge you can reference the Fuel Flow for a drop to 1/2 normal flow. At that warning you have 5 seconds to switch tanks with boost to prevent flame out.

Done properly it's a win-win.

Smokey
HR2

When your fuel flow approaches 60,000 PPH, I don't recommend it...:)
 
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