Forgive my ignorance - I'm a brand new "soon to be" RV-4 owner. Can anyone give me some guidance on the rules and regulations for running auto fuel in an RV? I am in the process of trading my Varga Kachina 2150A for a flying '92 RV-4. In the Varga, an STC is available to run auto fuel. I know that many people are running auto fuel in the RV's, but I cannot find anything about an STC nor an exemption for running the fuel in an experimental aircraft. The RV-4 has the low compression 150 hp IO-320. Am I missing something?
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Auto fuel mystery
- Thread starter MikeR
- Start date
rocketbob
Well Known Member
Nope, just fill her up and go! Well not quite. There's no paperwork required for a homebuilt to run mogas. Proceed cautiously by first mixing 50/50 with 100LL then gradually increase the ratio of mogas to 100LL after a few flights. What you are doing by doing that is validating that your fuel system is not routed in such a way which promotes vapor lock and that your supply of mogas is ethanol-free. I run 87 octane from the local farm bureau which contains no ethanol. I have run fuel with ethanol in the past. On a long taxi without the boost pump on it ran rough for a few seconds when it vapor locked. I've had it happen twice and both times were when the boost pump was off on the ground, on really hot days, ethanol blended gas. Turning on the pump took care of it. Tread carefully.
pierre smith
Well Known Member
Welcome..
...to VAF, Mike.
I just started running mogas in my -6A yesterday but ran 93 octane with no alcohol. One good bit of advice is to be sure and firesleeve the fuel line all the way to the carburetor. It helps keep the fuel cool and prevent vapor lock, and is available from Aircraft Spruce and other aviation suppliers. You're also allowed to do this mod without any paperwork...part of the beauty of owning an experimental....you can do all of your own maintenance. Consider also joining EAA (www.eaa.org). Find a gas station that has an owner you can talk to and whether or not they have alcohol in their fuel. Avoid it if you can since the general consensus is that alcohol may degrade the rubber in your fuel system.
BTW, I believe you'll never regret trading for the -4
Again, welcome,
...to VAF, Mike.
I just started running mogas in my -6A yesterday but ran 93 octane with no alcohol. One good bit of advice is to be sure and firesleeve the fuel line all the way to the carburetor. It helps keep the fuel cool and prevent vapor lock, and is available from Aircraft Spruce and other aviation suppliers. You're also allowed to do this mod without any paperwork...part of the beauty of owning an experimental....you can do all of your own maintenance. Consider also joining EAA (www.eaa.org). Find a gas station that has an owner you can talk to and whether or not they have alcohol in their fuel. Avoid it if you can since the general consensus is that alcohol may degrade the rubber in your fuel system.
BTW, I believe you'll never regret trading for the -4
Again, welcome,
You guys are awesome!
I've been doing 90% of my maintenance with an IA at my side and learning at lot. As I understand it with an experimental, I can do the majority of my maintenance, but still need to have a "normal" annual inspection signed off by the IA. Is this correct?
I've been doing 90% of my maintenance with an IA at my side and learning at lot. As I understand it with an experimental, I can do the majority of my maintenance, but still need to have a "normal" annual inspection signed off by the IA. Is this correct?
Geico266
Well Known Member
Be very careful about fuel contamination. Check, double check, your "system" and use a filter when adding fuel to your tanks. What ever method you are using for transporting fuel you need to take a minute and think about storage, transporting, transferring, filtering, maintenance, ect.
What will bite you is contamination from hoses, water separation, water getting into the containers, ect.
Don't let autogas be exposed to moving air (sealed containers, close vents)
Don't let auto gas sit for more than 30 days. It looses 2 octane points every 30 days. Fresh fuel only.
Autogas hold water in suspension that come into solution (collects at the bottom) when it gets cold. Sump tanks, every flying day! No exceptions!
Be vigilant for contamination of any source. You are the only quality control person making sure it is done right.
Obviously, CA won't have too much temps variations like the Midwest.
You get the point.
What will bite you is contamination from hoses, water separation, water getting into the containers, ect.
Don't let autogas be exposed to moving air (sealed containers, close vents)
Don't let auto gas sit for more than 30 days. It looses 2 octane points every 30 days. Fresh fuel only.
Autogas hold water in suspension that come into solution (collects at the bottom) when it gets cold. Sump tanks, every flying day! No exceptions!
Be vigilant for contamination of any source. You are the only quality control person making sure it is done right.
Obviously, CA won't have too much temps variations like the Midwest.
You get the point.
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pierre smith
Well Known Member
Almost..
.....but not quite...it's even easier than that! An A@P will do, not necassary to have an IA. It's called a "Condition inspection" for us in the Experimental category and it needs a logbook entry.
Enjoy,
.....but not quite...it's even easier than that! An A@P will do, not necassary to have an IA. It's called a "Condition inspection" for us in the Experimental category and it needs a logbook entry.
Enjoy,
Geico266
Well Known Member
You can do any maintenance (simple or major) that you feel comfortable doing. Annuals (condition inspections) have to be done by an A&P.
Two weeks to go!
Two weeks to go until my trade goes through! The owner who now has the RV-4 loves his plane, but was not the original builder and hence, the cockpit is just too tight for him. I'm a few inches shorter and 30 pounds lighter so should fit just fine. The Varga is a lot of fun, but I want the taildragger and aerobatic endorsements. I've spent some time in a Citabria and a Pitts S2 but do not have a taildragger endorsement. By the way, for those who have never flown in a Pitts, that is one squirmish plane. She's every bit as happy going backwards down the runway instead of forwards. With that said, I have secured an instructor who will ensure my success.
Two weeks to go until my trade goes through! The owner who now has the RV-4 loves his plane, but was not the original builder and hence, the cockpit is just too tight for him. I'm a few inches shorter and 30 pounds lighter so should fit just fine. The Varga is a lot of fun, but I want the taildragger and aerobatic endorsements. I've spent some time in a Citabria and a Pitts S2 but do not have a taildragger endorsement. By the way, for those who have never flown in a Pitts, that is one squirmish plane. She's every bit as happy going backwards down the runway instead of forwards. With that said, I have secured an instructor who will ensure my success.
sprucemoose
Well Known Member
Ethanol in car gas
Your question is timely, since I am struggling right now with the decision to switch over to premium car gas. Gas prices being what they are, I suspect this will become more and more common.
On the issue of ethanol- several have mentioned being wary of running ethanol gas, due to vapor lock and seal issues. Peterson Aviation, the holders of the auto fuel STC for certified aircraft, talks about this on their website, http://www.autofuelstc.com/autofuelstc/pa/ethanol.html. They also have plans for a simple, inexpensive test device to measure alcohol content in gasoline. Anyone running car gas from the local station should consider making and using one of these.
Your question is timely, since I am struggling right now with the decision to switch over to premium car gas. Gas prices being what they are, I suspect this will become more and more common.
On the issue of ethanol- several have mentioned being wary of running ethanol gas, due to vapor lock and seal issues. Peterson Aviation, the holders of the auto fuel STC for certified aircraft, talks about this on their website, http://www.autofuelstc.com/autofuelstc/pa/ethanol.html. They also have plans for a simple, inexpensive test device to measure alcohol content in gasoline. Anyone running car gas from the local station should consider making and using one of these.
I've flown about 1500 hours on auto gas in about 10 different planes, certified (with STC of course!) and experimental. It works great and I've had less issues with water, contamination, etc. than I have with AVGAS bought at airports. That being said, you do have to be careful, and all the advice given is right on the money. Especially about the firesleeve on the fuel line. And watch out for how it is run as well, proximity to exhaust, etc.
There were issues with vapor lock in the RV series early on because of the combination of small fuel lines, tight cowls and lack of insulation -- people had problems with avgas and autofuel.
Good idea to run one tank with auto gas only in cruise flight first until you see how your plane and its system handles it. I did have one tank access panel that was sealed with the stuff that always stays gooey and never sets -- auto gas caused it to start leaking. Took the tank off, cleaned the gooey **** off, sealed with proseal -- good to go, no more leaks.
I used to sample for alcohol every 4-5 loads even though I only bought from guaranteed, "no ethanol" stations, but now check every single time since it's more prevalent.
If you're running a 160HP or 180HP make sure to use premium.
There were issues with vapor lock in the RV series early on because of the combination of small fuel lines, tight cowls and lack of insulation -- people had problems with avgas and autofuel.
Good idea to run one tank with auto gas only in cruise flight first until you see how your plane and its system handles it. I did have one tank access panel that was sealed with the stuff that always stays gooey and never sets -- auto gas caused it to start leaking. Took the tank off, cleaned the gooey **** off, sealed with proseal -- good to go, no more leaks.
I used to sample for alcohol every 4-5 loads even though I only bought from guaranteed, "no ethanol" stations, but now check every single time since it's more prevalent.
If you're running a 160HP or 180HP make sure to use premium.
rocketbob
Well Known Member
I have a Hodges Fuel Volatility Tester, and use it occasionally. I haven't yet seen bad mogas. The mogas I run always tests very closely to what 100LL does. In fact you'd be surprised how easily 100LL starts bubbling in the tester.
I get mogas from the local farm bureau. Refined from oil wells in S. Illinois, and I like that. 100% American!
I want to emphasize that I run 87 octane in an O-360/Hartzell, and have no problems. I've borescoped the engine to look for signs of detonation or preignition and haven't found anything amiss.
I get mogas from the local farm bureau. Refined from oil wells in S. Illinois, and I like that. 100% American!
I want to emphasize that I run 87 octane in an O-360/Hartzell, and have no problems. I've borescoped the engine to look for signs of detonation or preignition and haven't found anything amiss.
Yes, ALWAYS test for ethanol. Because of prices of various octane enhancers, producers now sometimes use ethanol because of cost, not because it is required.
Pumps are supposed to be placarded if they have ethanol, but that doesn't always happen. Just filled my truck yesterday at a very large station in an area where ethanol is required and there were no placards. And if you are near an area that requires ethanol, you might still find it in your fuel even if the station where you are buying it from isn't required to pump it. Happened to me once; I bought 50 cents worth for testing before I filled my jugs for my plane. Probably a matter of what they had on the truck when they went from one station to another.
Richard Scott
RV-9A Fuselage
Pumps are supposed to be placarded if they have ethanol, but that doesn't always happen. Just filled my truck yesterday at a very large station in an area where ethanol is required and there were no placards. And if you are near an area that requires ethanol, you might still find it in your fuel even if the station where you are buying it from isn't required to pump it. Happened to me once; I bought 50 cents worth for testing before I filled my jugs for my plane. Probably a matter of what they had on the truck when they went from one station to another.
Richard Scott
RV-9A Fuselage
Ethanol
I'll add to my earlier short post. The newspaper article said that in Missouri, the stations had changed about 2 years earlier, but had not told anyone, and they had not changed prices either. The article said they were trying to prove that Ethanol used in cars does not create a problem. They said they had not had one complaint. For aviation, you need to know what you are using. Testing may be the only method to protect yourself.
John Bender
I'll add to my earlier short post. The newspaper article said that in Missouri, the stations had changed about 2 years earlier, but had not told anyone, and they had not changed prices either. The article said they were trying to prove that Ethanol used in cars does not create a problem. They said they had not had one complaint. For aviation, you need to know what you are using. Testing may be the only method to protect yourself.
John Bender
Masterplumber
Active Member
Missouri ethanol
I live in Jeff City, MO and read that article as well. I very regularly trip the odometer on my SUV with every fill up. Usually right at 320 to 330 miles when I need to fill up. I noticed last summer that that number fell to 280 miles for no apparent reason. i assume that was when they switched to ethanol without telling us.
I figure about 2 gallons a tank I lose with the new blend. Otherwise known as a 6 dollars a tank hidden tax.
Do be careful in Missouri, I'm suspicious there are very loose controls on the blending.
I live in Jeff City, MO and read that article as well. I very regularly trip the odometer on my SUV with every fill up. Usually right at 320 to 330 miles when I need to fill up. I noticed last summer that that number fell to 280 miles for no apparent reason. i assume that was when they switched to ethanol without telling us.
I figure about 2 gallons a tank I lose with the new blend. Otherwise known as a 6 dollars a tank hidden tax.
Do be careful in Missouri, I'm suspicious there are very loose controls on the blending.
Jerry Cochran
Well Known Member
Inspections: Get the right (RV) guy!
Before I got my -6a flying, we had to have an A&P do the condition inspection on an RV we bought.
The first 2 were done by 2 different guys who were not conversant with the Experimental world,so they kept searching for nonexistent AD's, etc. while we paid to educate them. Finally we found a local RV builder who had an A&P ticket, then it went very smoothly. Jeff supervised the work we did, then signed off for us. I'd suggest you do something like that. These guys from the certified world don't understand ours until they do a little building themselves...
Jerry
Before I got my -6a flying, we had to have an A&P do the condition inspection on an RV we bought.
The first 2 were done by 2 different guys who were not conversant with the Experimental world,so they kept searching for nonexistent AD's, etc. while we paid to educate them. Finally we found a local RV builder who had an A&P ticket, then it went very smoothly. Jeff supervised the work we did, then signed off for us. I'd suggest you do something like that. These guys from the certified world don't understand ours until they do a little building themselves...
Jerry
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Jerry Cochran
Well Known Member
Ethanol test
I wouldn't trust any source of mogas until I test it. I keep 6 gal plastic cans and won't fuel the airplane until I have done the test and found ethanol free. The EAA has a simple test kit for this or make your own.
Briefly, take a container, put one part water in it, mark the level, then add 4 parts gasoline. Cap it, shake thoroughly, let set an hour. If water level has risen above the mark, ethanol is in the fuel. Water loves alcohol more than gas does and steals it. A clear plastic pop bottle works well.
Of course, as always, be aware gasoline is highly flammable, so use all normal precautions...
Jerry
I wouldn't trust any source of mogas until I test it. I keep 6 gal plastic cans and won't fuel the airplane until I have done the test and found ethanol free. The EAA has a simple test kit for this or make your own.
Briefly, take a container, put one part water in it, mark the level, then add 4 parts gasoline. Cap it, shake thoroughly, let set an hour. If water level has risen above the mark, ethanol is in the fuel. Water loves alcohol more than gas does and steals it. A clear plastic pop bottle works well.
Of course, as always, be aware gasoline is highly flammable, so use all normal precautions...
Jerry
The original builder if he holds the repairman's certificate can also do the condition inspection.
Hmmm. My instructions that came with my autogas STC say 1 part water to 9 parts gas. If ethanol is present, it shows up in a matter of a minute or two, after a good shake, although the instructions say to let is sit for several minutes--I don't remember exactly how long, but it isn't any where near an hour. Shows up quickly enough that we test it at the gas station before filling our jugs.
Richard Scott
RV-9A Fuselage
1941 Interstate Cadet
Richard Scott
RV-9A Fuselage
1941 Interstate Cadet
Jerry Cochran
Well Known Member
Ethanol test part deux..
Right you are Richard,
I just said an hour because that's my habit. You can probably tell right away, I just go longer to try and determine the exact amount, thasall... Whatever the amount of fuel you use, the rise in H2O apparent level is the amount in that particular sample. But... I'm picking nits... The main thing is to do the test.
Jerry
Right you are Richard,
I just said an hour because that's my habit. You can probably tell right away, I just go longer to try and determine the exact amount, thasall... Whatever the amount of fuel you use, the rise in H2O apparent level is the amount in that particular sample. But... I'm picking nits... The main thing is to do the test.
Jerry
brayski98
Well Known Member
Ignorance
Pardon my ignorance on this, but is it okay to switch back and forth. Filling the RV while at my home base (KFUL) is fine, but isn't it hard to find when on a cross-country flight?
I have been considering this as well due to rising fuel costs. 100LL at KFUL is $4.50. Premium MoGas is $3.33.
So if I were flying cross country, is it okay to start with MoGas and then switch to 100LL when refueling?
Pardon my ignorance on this, but is it okay to switch back and forth. Filling the RV while at my home base (KFUL) is fine, but isn't it hard to find when on a cross-country flight?
I have been considering this as well due to rising fuel costs. 100LL at KFUL is $4.50. Premium MoGas is $3.33.
So if I were flying cross country, is it okay to start with MoGas and then switch to 100LL when refueling?
Our prices are now about $8 for mogas and $12.5 for AVGAS... AVGAS went up about $3.2 while the year changed. Yes, I'm truly interested using anything else than 100LL.
Rates used: 1 gallon is 3.8 liters and exchange rate of 1.47 dollar is 1 euro.
Octane and Volatility
"I want to emphasize that I run 87 octane in an O-360/Hartzell, and have no problems. I've borescoped the engine to look for signs of detonation or preignition and haven't found anything amiss"
Highly unrecommended procedure to check for detonation after the fact. Running fuel with an octane rating lower than what the engine manufacturer recommends puts you closer to "the edge" of having a detonation problem. You may get away with it for awhile and feel that it is OK. Then one hot day on a long climb to clear a ridge etc. it could really bite.
Another item:
Be aware of the different blends of auto fuel in winter and summer. Winter blend is more volatile for easier starting, but this also means easier vapor lock in the summer. Not real an issue unless you store your auto fuel for future use.
Someone mentioned that auto fuel drops a certain percentage of octane for each 30 days of storage. I question this as I am aware of how long fuel stays in storage at times before we get it into our cars. I suspect this might be the case if the fuel is in an open container where some of the components can evaporate off.
Randy C
"I want to emphasize that I run 87 octane in an O-360/Hartzell, and have no problems. I've borescoped the engine to look for signs of detonation or preignition and haven't found anything amiss"
Highly unrecommended procedure to check for detonation after the fact. Running fuel with an octane rating lower than what the engine manufacturer recommends puts you closer to "the edge" of having a detonation problem. You may get away with it for awhile and feel that it is OK. Then one hot day on a long climb to clear a ridge etc. it could really bite.
Another item:
Be aware of the different blends of auto fuel in winter and summer. Winter blend is more volatile for easier starting, but this also means easier vapor lock in the summer. Not real an issue unless you store your auto fuel for future use.
Someone mentioned that auto fuel drops a certain percentage of octane for each 30 days of storage. I question this as I am aware of how long fuel stays in storage at times before we get it into our cars. I suspect this might be the case if the fuel is in an open container where some of the components can evaporate off.
Randy C
rocketbob
Well Known Member
How else do you check for signs detonation in a Lycoming?
Over 5 years and 700 hours of running 87, no problems. Many takeoffs and climbs with OAT over 90 degrees, lots of acro and formation, and generally run hard. One particular climb I made this past summer was to 7500 ft, 95 OAT, running nothing but 87 octane. No problems at any time of the year, or after extended periods of non-flying. Last year I was snowed in for six weeks (grass strip) and didn't have anything but 87 in the tanks, fired it up and went flying.
Last November once again I borescoped the cylinders...I do keep an eye on things because I run 87 octane. I saw nothing but the lead stuck on the face of the piston that's there from running 100LL on trips.
I always go to 25 square on climb out, and climb no less than 120 to keep the engine and oil cool.
My experience has shown me that Lycomings are more detonation resistant than people think. I have yet to see or hear of a Lycoming that has burned up from detonation or preignition from running mogas.
We have several airplanes on our airport that have autofuel STC's and run the same mogas I buy, they don't have any issues either.
