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#1
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PA32-260 Auto Fuel STC
Does anyone know if there is an STC for use of auto fuel in a PA32-260.
I've been unable to find one. At $3.30/gal for avgas at KBHM I've got to stop the bleeding a bit. Thanks in advance. Bruce McFadden Birmingham, AL PA32-260 N5594J |
#2
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Bruce McFadden wrote:
Does anyone know if there is an STC for use of auto fuel in a PA32-260. I've been unable to find one. At $3.30/gal for avgas at KBHM I've got to stop the bleeding a bit. The two auto fuel stc holders are Petersen and the EAA. Neither of them do the PA-32 (or any twins to my knowledge). |
#3
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Bruce McFadden wrote:
Does anyone know if there is an STC for use of auto fuel in a PA32-260. I've been unable to find one. At $3.30/gal for avgas at KBHM I've got to stop the bleeding a bit. Whoops, the PA-32 isn't a twin, my bad. Still neither the EAA nor Petersen have an STC for it. The URLS a http://www.eaa.org/education/fuel/ for the EAA and http://www.autofuelstc.com/ for Petersen. Petersen used to have a list of airframes tested and failed but I can't find it. You might email them. They do support some O-540 models (this is what you have right?) but the airframe isn't listed. |
#4
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Petersen used to have a list of airframes tested and failed but I can't
find it. You might email them. They do support some O-540 models (this is what you have right?) but the airframe isn't listed. My O-540 is approved for car gas. It's got to be the low-compression version to be eligible. -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
#5
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Jay Honeck wrote:
Petersen used to have a list of airframes tested and failed but I can't find it. You might email them. They do support some O-540 models (this is what you have right?) but the airframe isn't listed. My O-540 is approved for car gas. It's got to be the low-compression version to be eligible. The PA-32-260 engine variant (E4B5 or whatever) is in Petersen's list as one of the 91 octane engines. However, the airframe isn't approved. |
#6
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The PA-32-260 engine variant (E4B5 or whatever) is in Petersen's list as
one of the 91 octane engines. However, the airframe isn't approved. That sucks. Guess I'll never buy a Six. How does an airframe difference matter to what fuel the engine uses? -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
#7
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Jay Honeck wrote:
The PA-32-260 engine variant (E4B5 or whatever) is in Petersen's list as one of the 91 octane engines. However, the airframe isn't approved. That sucks. Guess I'll never buy a Six. How does an airframe difference matter to what fuel the engine uses? Fuel lines, fuel pumps, and vapor lock issues. Lots of information on this on the Petersen web pages if you want the details. They don't do Navions (with any sort of engine). I asked for details once and the emailed me back that they had tested it and it failed the vapor lock tests. I asked for further configuration information because even with the E-185 (original Navion engine) there were two different fuel configurations (that's the difference between the Navion and Navion A), and then there are other engines (also on the approved list) that the factory and/or outsiders have added. |
#8
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Ron Natalie wrote: Petersen used to have a list of airframes tested and failed but I can't find it. It's now buried in the text. Click on the word "airframes." The URL is http://www.autofuelstc.com/autofuels...Airframes.html Still, they have a note there to call them if you don't see your plane listed. Apparently they have STCs for some aircraft that are rare. George Patterson The desire for safety stands against every great and noble enterprise. |
#9
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I know anecdotally from my IA that some of the Cherokees are somewhat
marginal in their ability to handle the high vapor pressures of winter autofuel. They would stumble on takeoff & climbout the first hot days of spring. The symptoms that I had heard sounded more like flooding rather than fuel starvation. It could be that the floats were sinking in the carb bowl as the fuel was boiling. The front of the bowl is close to very hot exhaust pipes, and the bowl vent is back directly into the air intake. Any one else know any more than this? I had heard some of the Grummans have had the autofuel STC pulled for similar reasons. Those of us using the autofuel STCs have to be cognizant of its possible limitations. It has worked well so far in my 172M (about 15 years), but I avoid flying in very hot weather and avoid parking bright sun (being concerned about fuel tank heating) just on principle. I'll let someone else verify that experiment. Pilots talk about the vapor pressure as though it is an absolute measure. It is not as it doubles about every 15 degreesF. Raising a fuel temp 15 degrees F will increase the actual vapor pressure of avgas enough to eliminate the measured reduced pressure benefit of avgas. In other words, autofuel has a 15 deg F handicap in handling high fuel temps. Octane requirements are a separate issue. The 235 HP Cherokee is an 80 octane engine, the 260 requires higher octane than regular. (Petersen is no relation to me) |
#10
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nrp wrote:
: I know anecdotally from my IA that some of the Cherokees are somewhat : marginal in their ability to handle the high vapor pressures of winter : autofuel. They would stumble on takeoff & climbout the first hot days : of spring. True enough of any aircraft, but the Cherokees' stock fuel system is a bit marginal to begin with. We got the STC for our 180 HP O-360 Cherokee and it required electric boost pump replacement. After that, we never got reduced fuel pressure at full power, full-rich, max nose-high attitude like we did with the stock pump. To give you another piece of info. If you have an O-320 *low-compression* (150hp), you get the 87 AKI autogas STC and keep the stock fuel pump. If you do *NOTHING* but swap pistons in the engine and turn it into a 160 hp, you need to swap out the fuel pumps due to "flow" issues. There's no difference in fuel flow by putting in high-compression pistons since everything else is kept constant. : The symptoms that I had heard sounded more like flooding rather than : fuel starvation. It could be that the floats were sinking in the carb : bowl as the fuel was boiling. The front of the bowl is close to very : hot exhaust pipes, and the bowl vent is back directly into the air : intake. Any one else know any more than this? Sounds reasonable. I talked with Petersen about this and he said that the PA-24 (Commanche) failed due to "hydro-locking." Boiling fuel in the carb sinking the float would certainly cause flooding and hydro-locking. : I had heard some of the Grummans have had the autofuel STC pulled for : similar reasons. Quite possible. They're a bit tigher cowled than the PA-28's. : Those of us using the autofuel STCs have to be cognizant of its : possible limitations. It has worked well so far in my 172M (about 15 : years), but I avoid flying in very hot weather and avoid parking bright : sun (being concerned about fuel tank heating) just on principle. I'll : let someone else verify that experiment. Absolutely. I'm especially leary of the octane rating for the high-compression STC (like I have). Most autogas with a 93 rating only has an 88 or so *motor* rating... which is similar to the avgas lean rating. As such, I like to have some 100LL in at least the takeoff tank... particularly on hot days. Also, autogas tends to have trace amounts of gunk/water in it. A screw-on water-separating filter on the gascan lids took care of that. : Pilots talk about the vapor pressure as though it is an absolute : measure. It is not as it doubles about every 15 degreesF. Raising a : fuel temp 15 degrees F will increase the actual vapor pressure of avgas : enough to eliminate the measured reduced pressure benefit of avgas. In : other words, autofuel has a 15 deg F handicap in handling high fuel : temps. True. Petersen sells a vapor pressure tester. Basically just a syringe with a screw-on gauage that you can pull a vacuum on a fuel sample until it boils. I always see 100LL about 1" higher than autogas, but on all but the ugliest days the autogas reads in the green on the gauge. : Octane requirements are a separate issue. The 235 HP Cherokee is an 80 : octane engine, the 260 requires higher octane than regular. : (Petersen is no relation to me) I think the PA-32 can have the O-540-E4B5... that's on the 91 engines list. No PA-32 that I can see on the airframe list. -- ************************************************** *********************** * Cory Papenfuss * * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * ************************************************** *********************** |
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