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#21
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![]() Guy Byars wrote: I try and keep a 50/50 mix of av/auto gas in my Skylane. More avgas in the winter, more autogas in the summer. Shouldn't it be the other way around, if you're concerned about vapor lock? Autogas in winter makes starting much easier due to its higher vapor pressure. |
#22
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Congratulations, I think you'll like the plane. I have the F model with
a 180 hp coversion and C/S prop. I do like the extra hp. I am interested where you live and what you get (amenities) for the $250/month hangar. Ross KSWI houstondan wrote: my first airplane. cessna 172C. this group, along with a couple of others, has given me the best information as i've progressed. by way of payback, i intend to tell some about the process i went thru for the benefit of others who may be planning; hoping. why a 172-c?? well, a couple of reasons. mechanical flaps (you pull a rod that's laying on the floor) and the 6 cylinder engine which, although it is 5-15 hp light of later models, is smooth music compared to the banging of the 4s. any airport in america has mechanics and parts to fix a 172. it is slow by most standards but i think i see 15/mpg which ain't that bad considering the advantage you get over cars on "direct route". i'm retired; i've got lots of time. i paid 34k$ and wells fargo financed me at 7.75 for 15 years. makes it managable. very friendly people. i like them. i joined aopa and subscribed to trade-a-plane and g.a. news. haunted the web for any and all information i could find on airplanes including the new light sport stuff. every evening, or something close to that, i would read the adds in trade a plane and e-bay and whatever i could find untill i had a good working understanding of the issues around aircraft purchase and ownership. i have not been flying much lately because i knew i would need the money to buy - not rent. when the plane showed-up at my local airport, i expressed interest and had the owner agree to a full inspection by my mechanic. that uncovered an exhaust valve problem. he fixed it and we closed today. yipee!! i now own a plane. had my mechanic not examined the plane then i would be looking at a grand in engine fix already. now, at least, i've got all 6 doing well north of 70lbs. i''ll be joining the cessna pilots assn. shortly. thanks y'all who advised there. hooks airport is renting t-hangers at 250/month and i'll be getting one tomorrow. i really like having a tin box for my bird. anyway, that's my experience so for. hope it helps. i can see that i'm going to be needing a lot of money for gas. dan |
#23
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![]() Autogas in winter makes starting much easier due to its higher vapor pressure. I have heard a lot of arguments about vapor lock, but I do not understand how vapor lock could ever be a problem in a Cessna 182. With the high wing configuration, the carberator will always have a positive fuel pressure due to hydrostaic pressure. How can vapor lock *EVER* happen in a Skylane? As an engineer, I don't see it happening. Now, on the other hand, if you have a low wing airplane with a fuel pump, then vapor lock is a very real problem. But vapor lock in a high wing carberated engine.... not possible. |
#24
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In article ,
"Guy Byars" wrote: Autogas in winter makes starting much easier due to its higher vapor pressure. I have heard a lot of arguments about vapor lock, but I do not understand how vapor lock could ever be a problem in a Cessna 182. With the high wing configuration, the carberator will always have a positive fuel pressure due to hydrostaic pressure. How can vapor lock *EVER* happen in a Skylane? As an engineer, I don't see it happening. Now, on the other hand, if you have a low wing airplane with a fuel pump, then vapor lock is a very real problem. But vapor lock in a high wing carberated engine.... not possible. Au contriare, mon ami! Piper Tripacer running avgas on a hot summer day can vapor lock. It's all in how and where the plumbing is routed from the wing to the engine. |
#25
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Congrats! Next thing on your "to do" list:
Go to www.cessna.org and join the Cessna Pilots Association. Lots of good info on how to maintain it. Chris "houstondan" wrote in message ups.com... my first airplane. cessna 172C. this group, along with a couple of others, has given me the best information as i've progressed. by way of payback, i intend to tell some about the process i went thru for the benefit of others who may be planning; hoping. why a 172-c?? well, a couple of reasons. mechanical flaps (you pull a rod that's laying on the floor) and the 6 cylinder engine which, although it is 5-15 hp light of later models, is smooth music compared to the banging of the 4s. any airport in america has mechanics and parts to fix a 172. it is slow by most standards but i think i see 15/mpg which ain't that bad considering the advantage you get over cars on "direct route". i'm retired; i've got lots of time. i paid 34k$ and wells fargo financed me at 7.75 for 15 years. makes it managable. very friendly people. i like them. i joined aopa and subscribed to trade-a-plane and g.a. news. haunted the web for any and all information i could find on airplanes including the new light sport stuff. every evening, or something close to that, i would read the adds in trade a plane and e-bay and whatever i could find untill i had a good working understanding of the issues around aircraft purchase and ownership. i have not been flying much lately because i knew i would need the money to buy - not rent. when the plane showed-up at my local airport, i expressed interest and had the owner agree to a full inspection by my mechanic. that uncovered an exhaust valve problem. he fixed it and we closed today. yipee!! i now own a plane. had my mechanic not examined the plane then i would be looking at a grand in engine fix already. now, at least, i've got all 6 doing well north of 70lbs. i''ll be joining the cessna pilots assn. shortly. thanks y'all who advised there. hooks airport is renting t-hangers at 250/month and i'll be getting one tomorrow. i really like having a tin box for my bird. anyway, that's my experience so for. hope it helps. i can see that i'm going to be needing a lot of money for gas. dan |
#26
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![]() Of course it's possible. On a hot day if the plane is flown and then parked on the ramp with the cowling closed, the heat under the cowling can be so intense that it can potentially vaporize the fuel in the fuel lines forward of the firewall. If the engine is restarted shortly afterwards it's possible to experience vapor lock. This problem will be worse if higher vapor pressure fuel is used (such as winter blend autogas). The solution is surprisingly easy. During those short turn-around always open the cowling immediately after the shutdown. That'll let the heat escape and avoid the vapor lock. Guy Byars wrote: I have heard a lot of arguments about vapor lock, but I do not understand how vapor lock could ever be a problem in a Cessna 182. With the high wing configuration, the carberator will always have a positive fuel pressure due to hydrostaic pressure. How can vapor lock *EVER* happen in a Skylane? As an engineer, I don't see it happening. Now, on the other hand, if you have a low wing airplane with a fuel pump, then vapor lock is a very real problem. But vapor lock in a high wing carberated engine.... not possible. |
#27
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![]() Of course it's possible. On a hot day if the plane is flown and then parked on the ramp with the cowling closed, the heat under the cowling can be so intense that it can potentially vaporize the fuel in the fuel lines forward of the firewall. If the engine is restarted shortly afterwards it's possible to experience vapor lock. This problem will be worse if higher vapor pressure fuel is used (such as winter blend autogas). The solution is surprisingly easy. During those short turn-around always open the cowling immediately after the shutdown. That'll let the heat escape and avoid the vapor lock. Guy Byars wrote: I have heard a lot of arguments about vapor lock, but I do not understand how vapor lock could ever be a problem in a Cessna 182. With the high wing configuration, the carberator will always have a positive fuel pressure due to hydrostaic pressure. How can vapor lock *EVER* happen in a Skylane? As an engineer, I don't see it happening. Now, on the other hand, if you have a low wing airplane with a fuel pump, then vapor lock is a very real problem. But vapor lock in a high wing carberated engine.... not possible. |
#28
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Vapor lock is a starving of fuel at the carb bowl while a low
pressure-high temperature area in the fuel delivery system delivers enough vapor that the fuel pump can't get to liquid fuel. You just don't have that situation in a gravity system. What you may be considering vapor lock in a gravity system may be fuel boiling in the carb bowl due to radiated heat from the exhaust system. This causes the float to sink in the "foam fuel". The bowl then overfills, and the excess fuel is vented from the bowl into the air intake, flooding the engine. The key is that all aircraft carbs vent the bowl to the air intake, allowing a way to flood the engine. This is not very well publicized. TriPacers probably flood the second way. Cherokees could go either way. Does this jibe with any observations? Comments? |
#29
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joined c.p.a. but they say they're in the middle of a move this weekend
so it'll be a couple of days before that's complete. dan |
#30
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I recall some planes getting ito trouble on autogas when they went too
high in the summer. Guy Byars wrote: Autogas in winter makes starting much easier due to its higher vapor pressure. I have heard a lot of arguments about vapor lock, but I do not understand how vapor lock could ever be a problem in a Cessna 182. With the high wing configuration, the carberator will always have a positive fuel pressure due to hydrostaic pressure. How can vapor lock *EVER* happen in a Skylane? As an engineer, I don't see it happening. Now, on the other hand, if you have a low wing airplane with a fuel pump, then vapor lock is a very real problem. But vapor lock in a high wing carberated engine.... not possible. |
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