Aviation Fuel for chainsaws ?
- Thread starter fixitguy75
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Thats completley false.
HIGH OCTANE FUEL DOES NOT BURN SLOWER OR COOLER THAN LOW OCTANE FUEL! This is fact.
I am sick of posting links with referances to refute this crap.:deadhorse:
Do a search and you will see that in the past I have provided more than ample proof from very reliable sources to prove my point.
Here is the last goa orund we had.
http://www.arboristsite.com/showthread.php?t=30522&highlight=octane
http://www.arboristsite.com/showthread.php?t=30522&highlight=octane
ShoerFast
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Ben Walker
Slow may not be as good a word as using a term like "higher octane fuels burn more evenly" (even pressure rise, resist detanation) What brings the word slower is the fact that some slower burning fuels just do have a higher octane rating,,,,,,,,,,Just look at RVP's of winter fuels and listen to how they will ping (when hot) in older engines, or seem less power on newer engines.
AC engines need the TQ, there mostly way over stroked engines, the way to keep burn pressures and detanation down (as long stroke vs flame front travel = creeping high pressures) is to have relativity late Ing. timing and to run high O-rating fuels.
A racing or work trick, (on some engines) is to mist water into the induct to gain power with marginal fuels, old farm tractors could run K-1 in a gas engines with water to keep them from detonating apart. Piston fighter aircraft (WWII) ran water on take-off and dog-fights. Water cooled the air charge, and slowed the burn rate.
Here is a picture of pure K-1 fuel in a GE-J-85-5 engine (F-5 Fighter), just after start up:
Slow may not be as good a word as using a term like "higher octane fuels burn more evenly" (even pressure rise, resist detanation) What brings the word slower is the fact that some slower burning fuels just do have a higher octane rating,,,,,,,,,,Just look at RVP's of winter fuels and listen to how they will ping (when hot) in older engines, or seem less power on newer engines.
AC engines need the TQ, there mostly way over stroked engines, the way to keep burn pressures and detanation down (as long stroke vs flame front travel = creeping high pressures) is to have relativity late Ing. timing and to run high O-rating fuels.
A racing or work trick, (on some engines) is to mist water into the induct to gain power with marginal fuels, old farm tractors could run K-1 in a gas engines with water to keep them from detonating apart. Piston fighter aircraft (WWII) ran water on take-off and dog-fights. Water cooled the air charge, and slowed the burn rate.
Here is a picture of pure K-1 fuel in a GE-J-85-5 engine (F-5 Fighter), just after start up:
West Texas
ArboristSite Guru
Jeff you just keep saying the obvious. Do a search! 
Maybe there should be a 'primer' on this forum on how to 'do a search' as so few seem to be able to do it
Maybe there should be a 'primer' on this forum on how to 'do a search' as so few seem to be able to do it 
Been there, done that.
I have run 100LL, worked fine. Richen the H just a touch.
I might be tempted to run it again (someday). I could not tell any big difference in power. Explain to some other cutter that you are running AVGAS and they flip out! They think it must be rocket fuel or something! :hmm3grin2orange:
-pat
I have run 100LL, worked fine. Richen the H just a touch.
I might be tempted to run it again (someday). I could not tell any big difference in power. Explain to some other cutter that you are running AVGAS and they flip out! They think it must be rocket fuel or something! :hmm3grin2orange:
-pat
sanmigmike
ArboristSite Lurker
Old KC-135's
and a few other of the early jets used water injection on take off, saw a few wet take-offs at Edwards years ago and the steam, looked like smoke, could be impressive, we called them "water wagons". The early jets were pretty smokey dirty anyway, I heard somewhere that the early 707's and 8's would put out over 80 lbs of particulate crude each takeoff. I would tend to think that water that was injected was actually was a mixture of water and some sort of methanol or alcohol so that it would not freeze at altitude. I know it does cause some life problems in some turbine engines.
A lot of big piston engines did use AWI (alcohol water injection). You get to use a different set of power numbers for the wet take-offs, and all wet takes offs would be max power, no reason otherwise. Bigger airplanes do not always use full power for take off, reduced power take offs are normal, saves engine life. I seem to recall problems with engine life when you did too many wet takeoffs. I understand that you can also spray water in front of the radiator on the liquid cooled engines and improve the cooling, something about the increased mass flow rate through the radiator?
There are lots of different types of jet fuel, try bringing jp-4 aboard a carrier for example. Plain jet fuel isn't really seen any more, it had a problem of growing junk in it. You can buy additives for things growing in it as well as helping with fuel icing but if you burn the stuff the engine maker says to burn, no need, never worked for a company that added anything to their fuel.
I've never heard of routine draining of all the fuel for any normal aircraft. Our aircraft get a daily inspection that can include draining fuel but just small amounts. I've also flown airplanes that had EPA kits, a small tank that held a few cycles of few that used to be dumped on the ground when lines were emptied at shut down. If the mechs didn't drain the EPA tanks every few flights you started dumping fuel on the ramp again... I guess it does all add up, in commuter use an airplane might do four to eighteen legs in a day, a half cup from each engine each shutdown times all the airplanes...
We try to land with no less than around 18,000 lbs and if they plan to move the empty aircraft around on the ground they have to have at least 50,000 lbs of fuel. When we ferry an empty aircraft we usually need to take 50,000 lbs of ballast fuel that is considered unusable in flight. Draining the tanks would be a major effort and if it was done each time, wow, think of the time and the cost. So there is no normal draining of the entire fuel load. At times we have to reduce the fuel load and at almost all airports it has to go into a different fuel truck and is not pumped back into an airplane, considered contaminated.
Jet fuels, there are several of them and most jet engines will burn most jet fuels but with time limits and performance limits. We also get temp limits, the outside airtemp at altitude versus time and fuel temp, the fuel will start to gell up and not flow when it gets really cold and that does vary as to the exact fuel. Jet engines will burn just about anything, I think I flew one turbine that let you burn some avgas in it, very strict limits though, time and percentage of av gas to the jet fuel. Diesel would work but I would not burn it, the liability for burning something not in the flight manual or approved for aircraft use would be immense.
Jet fuels have a wide range of density so our gauges read lbs, not gallons. In flight test we ran a density check on the fuel right before each flight and then used the gauges and a calibration sheet for that gauge in that aircraft for the actual fuel weight for that flight. On the line we use the gauge.
Water is hard to spot in jet A-1 ( the more common commercial jet fuel), or any of the normal jet fuels but easy to spot in piston fuel, given time to settle. Jet fuel is straw, piston (might be wrong, been a while since I have flown piston): 80/87 was red, 100 was blue and 100LL was green. Then of course the purple stuff. I think some is still being made for air racing. I would drain about a cup to a pint a day from the truck, never more than a half cup from each tank sump on the airplane for avgas . Never drained a turbine fuel sump! Most places just have 100LL (low lead) fuel and when I was flying pistons it did tend to foul the plugs on engines that were built for 80/87. I think it has three or four times the lead of 80/87. Always wanted to fly something that used the higher octane fuel, I think 115/145 but the fuel is rare now and the Connie's and so on that you see at airshows are running at reduced power since you can't really get the purple stuff anymore. I guess to be technical the higher numbers are not octane numbers but that's what we called them and that's what was in the flight manuals.
You can get supplemental type certificates to run auto gas in some engines/aircraft. There are differences and I don't think you can use them in commercial use, like hauling pax or frieght, think you can do it for things such as ag flying. Since the vapour properties are different you can have altitude and other limits. Most of the piston engines I flew were really old technology, PW made the 1340 and 985 in the thirty's? Yes, you had a supercharger but you had to be kind of gentle and people didn't seem to get worried until you were using a gallon of oil per hour. Even the later things like the TSIO-540 was not all that high tech, had a turbo charger but now that isn't any big deal. Neat to see the turbo's glowing orange hot at night, you could set the mixture almost by looking at them. Turbine engines are almost bullet proof, the fuel control takes care of most fast throttle movements, most the ones now you cannot over temp in reverse and during takeoff most of them have auto throttles. The older turbines are still a lot easier to handle than most of the piston ones. I have sweated out hot starts on TSIO-540's on hot days, praying the battery will hold out and it not flood, or have to flood it to get it to start. A hot turbine, we used external power or an APU, if it is really hot, do a cooling cycle or or let it spin a little longer, watch the temp and when it is cool enough add the fuel. No sweat as long as you have electrical power. You do have to be careful of a wind up your tail!
The big difference in aviation fuel compared to auto fuel is that it is made to tighter standards and more care is taken of it in the supply line. The jet fuel trucks have all sorts of filters and some have water alert systems. I have seen jet fuel and av gas recalled. Have you ever seen your local gas station pump out bad fuel? Or a auto fuel supplier buy a lot of ruined engines...
Sorry to bore you but at last a topic I know something about!
and a few other of the early jets used water injection on take off, saw a few wet take-offs at Edwards years ago and the steam, looked like smoke, could be impressive, we called them "water wagons". The early jets were pretty smokey dirty anyway, I heard somewhere that the early 707's and 8's would put out over 80 lbs of particulate crude each takeoff. I would tend to think that water that was injected was actually was a mixture of water and some sort of methanol or alcohol so that it would not freeze at altitude. I know it does cause some life problems in some turbine engines.
A lot of big piston engines did use AWI (alcohol water injection). You get to use a different set of power numbers for the wet take-offs, and all wet takes offs would be max power, no reason otherwise. Bigger airplanes do not always use full power for take off, reduced power take offs are normal, saves engine life. I seem to recall problems with engine life when you did too many wet takeoffs. I understand that you can also spray water in front of the radiator on the liquid cooled engines and improve the cooling, something about the increased mass flow rate through the radiator?
There are lots of different types of jet fuel, try bringing jp-4 aboard a carrier for example. Plain jet fuel isn't really seen any more, it had a problem of growing junk in it. You can buy additives for things growing in it as well as helping with fuel icing but if you burn the stuff the engine maker says to burn, no need, never worked for a company that added anything to their fuel.
I've never heard of routine draining of all the fuel for any normal aircraft. Our aircraft get a daily inspection that can include draining fuel but just small amounts. I've also flown airplanes that had EPA kits, a small tank that held a few cycles of few that used to be dumped on the ground when lines were emptied at shut down. If the mechs didn't drain the EPA tanks every few flights you started dumping fuel on the ramp again... I guess it does all add up, in commuter use an airplane might do four to eighteen legs in a day, a half cup from each engine each shutdown times all the airplanes...
We try to land with no less than around 18,000 lbs and if they plan to move the empty aircraft around on the ground they have to have at least 50,000 lbs of fuel. When we ferry an empty aircraft we usually need to take 50,000 lbs of ballast fuel that is considered unusable in flight. Draining the tanks would be a major effort and if it was done each time, wow, think of the time and the cost. So there is no normal draining of the entire fuel load. At times we have to reduce the fuel load and at almost all airports it has to go into a different fuel truck and is not pumped back into an airplane, considered contaminated.
Jet fuels, there are several of them and most jet engines will burn most jet fuels but with time limits and performance limits. We also get temp limits, the outside airtemp at altitude versus time and fuel temp, the fuel will start to gell up and not flow when it gets really cold and that does vary as to the exact fuel. Jet engines will burn just about anything, I think I flew one turbine that let you burn some avgas in it, very strict limits though, time and percentage of av gas to the jet fuel. Diesel would work but I would not burn it, the liability for burning something not in the flight manual or approved for aircraft use would be immense.
Jet fuels have a wide range of density so our gauges read lbs, not gallons. In flight test we ran a density check on the fuel right before each flight and then used the gauges and a calibration sheet for that gauge in that aircraft for the actual fuel weight for that flight. On the line we use the gauge.
Water is hard to spot in jet A-1 ( the more common commercial jet fuel), or any of the normal jet fuels but easy to spot in piston fuel, given time to settle. Jet fuel is straw, piston (might be wrong, been a while since I have flown piston): 80/87 was red, 100 was blue and 100LL was green. Then of course the purple stuff. I think some is still being made for air racing. I would drain about a cup to a pint a day from the truck, never more than a half cup from each tank sump on the airplane for avgas . Never drained a turbine fuel sump! Most places just have 100LL (low lead) fuel and when I was flying pistons it did tend to foul the plugs on engines that were built for 80/87. I think it has three or four times the lead of 80/87. Always wanted to fly something that used the higher octane fuel, I think 115/145 but the fuel is rare now and the Connie's and so on that you see at airshows are running at reduced power since you can't really get the purple stuff anymore. I guess to be technical the higher numbers are not octane numbers but that's what we called them and that's what was in the flight manuals.
You can get supplemental type certificates to run auto gas in some engines/aircraft. There are differences and I don't think you can use them in commercial use, like hauling pax or frieght, think you can do it for things such as ag flying. Since the vapour properties are different you can have altitude and other limits. Most of the piston engines I flew were really old technology, PW made the 1340 and 985 in the thirty's? Yes, you had a supercharger but you had to be kind of gentle and people didn't seem to get worried until you were using a gallon of oil per hour. Even the later things like the TSIO-540 was not all that high tech, had a turbo charger but now that isn't any big deal. Neat to see the turbo's glowing orange hot at night, you could set the mixture almost by looking at them. Turbine engines are almost bullet proof, the fuel control takes care of most fast throttle movements, most the ones now you cannot over temp in reverse and during takeoff most of them have auto throttles. The older turbines are still a lot easier to handle than most of the piston ones. I have sweated out hot starts on TSIO-540's on hot days, praying the battery will hold out and it not flood, or have to flood it to get it to start. A hot turbine, we used external power or an APU, if it is really hot, do a cooling cycle or or let it spin a little longer, watch the temp and when it is cool enough add the fuel. No sweat as long as you have electrical power. You do have to be careful of a wind up your tail!
The big difference in aviation fuel compared to auto fuel is that it is made to tighter standards and more care is taken of it in the supply line. The jet fuel trucks have all sorts of filters and some have water alert systems. I have seen jet fuel and av gas recalled. Have you ever seen your local gas station pump out bad fuel? Or a auto fuel supplier buy a lot of ruined engines...
Sorry to bore you but at last a topic I know something about!
Paul61
ArboristSite Guru
Thanks for the info, hate to use it as a quote though!
Here's my 2 cents on the AV gas thing;
Used it for over 5 years in a 650 hp+ BB Chev. (@ 13.5:1 comp.) drag car as it was cheaper than using VP16, etc. NEVER had any engine problems (piston / bearing) .
As for the guy who holed pistons, guess you never had a look @ the plugs to set the correct mixture, huh?
AV gas requires a mixture change (richer), you CANNOT substitute a good grade of pump gas without carb. adjustments (low end as well).
Also, AV gas has an additive to prevent vapour lock (remember this happening to your 60's cars??), doesn't mean squat to your saw, although it can't hurt for you guys in the south!!
I'd run it if I could get it, the lead is a perfect detonation preventor, and
valve lubricator (N/A for saws!), but it was allready getting hard to buy back in the late 80's.
I don't beleive you'll make much more power without further eng. mods. (ie. increased compression) but, you'll not have to worry about engine destroying detonation especially when the saw gets hot.
To the guy who 1st asked.............., richen the high end and keep an eye on the plug color after some long cuts. Remember NOT to idle the saw before checking the plug color.
Oh yeah, it smells real good too!
Here's my 2 cents on the AV gas thing;
Used it for over 5 years in a 650 hp+ BB Chev. (@ 13.5:1 comp.) drag car as it was cheaper than using VP16, etc. NEVER had any engine problems (piston / bearing) .
As for the guy who holed pistons, guess you never had a look @ the plugs to set the correct mixture, huh?
AV gas requires a mixture change (richer), you CANNOT substitute a good grade of pump gas without carb. adjustments (low end as well).
Also, AV gas has an additive to prevent vapour lock (remember this happening to your 60's cars??), doesn't mean squat to your saw, although it can't hurt for you guys in the south!!
I'd run it if I could get it, the lead is a perfect detonation preventor, and
valve lubricator (N/A for saws!), but it was allready getting hard to buy back in the late 80's.
I don't beleive you'll make much more power without further eng. mods. (ie. increased compression) but, you'll not have to worry about engine destroying detonation especially when the saw gets hot.
To the guy who 1st asked.............., richen the high end and keep an eye on the plug color after some long cuts. Remember NOT to idle the saw before checking the plug color.
Oh yeah, it smells real good too!
