When should isopropyl alcohol be added to fuel?

FORANE

FORANE

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FORANE
Anyone do this in pistons?
When should it be done?

I had not heard of doing this in pistons but per wiki:
http://en.wikipedia.org/wiki/Fuel_syste ... _inhibitor
Fuel system icing inhibitor (FSII) is an additive to aviation fuels that prevents the formation of ice in fuel lines. FSII is sometimes referred to by the registered, genericized trademark Prist.
Anhydrous isopropyl alcohol is sometimes used as an alternative.
The mixture of FSII must be between 0.10% and 0.15% by volume for the additive to work correctly

Any concerns with alcohol compatibility in fuel systems at that low concentration?
 
I've never heard of it going into avgas, but we add it on request to our jet fuel. For every 100 gallons of jet fuel, we add about 16 ounces to ours, give or take.
 
The manual for my Socata Tampico TB9 says 1% isopropyl is OK.
 

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Piston GA in the lower 48? Never
 
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Sounds like prist works by absorbing the moisture. This is also what ethanol does. Since you're flying experimentals, if you've determined your fuel systems are ethanol safe, then just use a bit of E10, same difference (at least it seems). About a gallon per tank would likely be ample.

As an aside, I get a big kick out of seeing people buy Heet at WalMart or their local auto parts store these days. Talk about a complete waste of money in areas where E10 is the only game in town.
 
timwinters said:
Sounds like prist works by absorbing the moisture. This is also what ethanol does. Since you're flying experimentals, if you've determined your fuel systems are ethanol safe, then just use a bit of E10, same difference (at least it seems). About a gallon per tank would likely be ample.

As an aside, I get a big kick out of seeing people buy Heet at WalMart or their local auto parts store these days. Talk about a complete waste of money in areas where E10 is the only game in town.
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You are assuming that the fuel you get from the gas station is not already saturated with water from their tanks... :(
 
Kiddo's Driver said:
I agree, but there are provisions for it in my Pilot's Information Manual so I thought I would pass the info along.

Jim
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I'm guessing that's why the autogas STCs say "ethanol/alcohol content greater than 1% is prohibited". That seems to jive with anti-icing additive guidance.
 
For the folks in the never camp, would that also apply to the few pistons which operate in the flight levels?

Just for background perspective, this thread was inspired due to learning some of the Lancair 4p guys do this for northern 48 winter ops.
 
Condensation happens. Ice crystals form on exposed fuel tank walls during winter. The problem is that for guys who operate and park in sub-freezing weather is we can't drain anything from our sumps unless the temps support melting the ice. The only way to eliminate the ice is by adding isopropyl alcohol. If you use a heated hangar or live in temps that allow slumping fuel tanks you shouldn't need isopropyl unless you suspect a water problem.
 
FORANE said:
Anyone do this in pistons?
When should it be done?

I had not heard of doing this in pistons but per wiki:
http://en.wikipedia.org/wiki/Fuel_syste ... _inhibitor
Fuel system icing inhibitor (FSII) is an additive to aviation fuels that prevents the formation of ice in fuel lines. FSII is sometimes referred to by the registered, genericized trademark Prist.
Anhydrous isopropyl alcohol is sometimes used as an alternative.
The mixture of FSII must be between 0.10% and 0.15% by volume for the additive to work correctly

Any concerns with alcohol compatibility in fuel systems at that low concentration?
Click to expand...

Prist is used in JetA, and similar additives go into winterized diesel fuel.

If you have no water in your fuel tanks, you wouldn't use it at all with AvGas.
 
FORANE said:
For the folks in the never camp, would that also apply to the few pistons which operate in the flight levels?

Just for background perspective, this thread was inspired due to learning some of the Lancair 4p guys do this for northern 48 winter ops.
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With a recip/AvGas you use alcohol to fix a water/ice contamination problem, not as a preventative. Better to get into a heated hangar and get a good slosh and settle then sump it out, especially if you have bladders, if that's an option.

Some of the IVP guys are running turbines.
 
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Have never used it,If your worried about water in the tanks. Sump them out in a heated environment.
 
A few drops of water in the carb bowl can send you and your mechanic down a frustrating road trying to figure out why your fuel flows are lower than normal. That's a pirep. It isn't just a winter thing, this isopropyl.
 
Stewartb said:
A few drops of water in the carb bowl can send you and your mechanic down a frustrating road trying to figure out why your fuel flows are lower than normal. That's a pirep. It isn't just a winter thing, this isopropyl.
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True, you can use it to fix water problems regardless the temp.
 
Is less that 1% by volume going to "fix" a water problem? :dunno:
 
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Kiddo's Driver said:
It is Diethylene Glycol Monomethyl Ether
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When I order JetA I refuse to say "with prist", I do get a lot of strange looks when I say "75/side with FSII (pronounced fizzy)". Even worse when I say "may I get 50/side with Diethylene Glycol Monomethyl Ether."
 
NJP_MAN said:
When I order JetA I refuse to say "with prist", I do get a lot of strange looks when I say "75/side with FSII (pronounced fizzy)". Even worse when I say "may I get 50/side with Diethylene Glycol Monomethyl Ether."
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You put prist in that overgrown skyhawk? in Arizona? crazy man!
 
NJP_MAN said:
When I order JetA I refuse to say "with prist", I do get a lot of strange looks when I say "75/side with FSII (pronounced fizzy)". Even worse when I say "may I get 50/side with Diethylene Glycol Monomethyl Ether."
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The only term I have heard when ordering JetA is either Positive or Negative,,
 
N801BH said:
The only term I have heard when ordering JetA is either Positive or Negative,,
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I always called it Prist when I flew an airplane that needed it. The only time I was questioned was in Canada when the line guy told me Prist is illegal in Canada for environmental reasons. But they have some additive already in their fuel which is sufficient. You would think so, being in a cold place. :rofl:
 
Everskyward said:
I always called it Prist when I flew an airplane that needed it. The only time I was questioned was in Canada when the line guy told me Prist is illegal in Canada for environmental reasons. But they have some additive already in their fuel which is sufficient. You would think so, being in a cold place. :rofl:
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Wow.... If Canada says it an environmental hazard I am AMAZED California has not outlawed it there first...:dunno:...:confused:
 
I posted earlier this week on FB that I'm betting this gas station has a bunch of water-infused crap they have to pump out of the left tank, pretty soon...

4f73a91e7033c5ebc5161f23f5851a5d.jpg
 
denverpilot said:
I posted earlier this week on FB that I'm betting this gas station has a bunch of water-infused crap they have to pump out of the left tank, pretty soon...
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I noticed that E85 was a full dollar higher than regular unleaded about a month. Ago in St. Louis.

I laughed.
 
Clark1961 said:
You put prist in that overgrown skyhawk? in Arizona? crazy man!
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Yea. They think is has biocide qualities and I have been told that is debatable. But they want us to always get fuel positive.
 
It isn't added to jet by dumping it in. It has to be injected into the flow as you are pumping. We buy pre-mix where it is injected into the flow as it is being pumped into the over the road tanker. Our jet-A fuel truck has an injector but I don't want to mess with the stuff.
 
Kiddo's Driver said:
You are assuming that the fuel you get from the gas station is not already saturated with water from their tanks... :(
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Mogas can hold up to 1 teaspoon per gallon. It can be an issue of you don't sump the tanks and take other precautions. I get water collecting in the bottom of my transport tank once in a while, but not very often. The key is fly a lot! :lol:
 
I added 8 oz of 99% isopropyl to each tank on my Malibu during every other fill up in the winter. It's not fun when you loose a cylinder or two at FL250. You're coming down to much warmer air very quickly. I never had another problem with fuel system icing after my one event.

The fuel flow dividers on the TSIO520-BE and TSIO550-C engines are not heated and set up over the top of the engine too.
 
Geico266 said:
Mogas can hold up to 1 teaspoon per gallon. It can be an issue of you don't sump the tanks and take other precautions. I get water collecting in the bottom of my transport tank once in a while, but not very often. The key is fly a lot! :lol:
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My comment was about how buying E10 and using it to get the water out of your fuel system is not effective when the E10 is already loaded up with water from the station's tanks.
 
kmead said:
I added 8 oz of 99% isopropyl to each tank on my Malibu during every other fill up in the winter. It's not fun when you loose a cylinder or two at FL250. You're coming down to much warmer air very quickly. I never had another problem with fuel system icing after my one event.

The fuel flow dividers on the TSIO520-BE and TSIO550-C engines are not heated and set up over the top of the engine too.
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Kevin

I do not follow. Do you mean you now add every other fill up in winter or you did and have now stopped? As I read it you attribute your 1 event of cylinder loss to water in fuel freezing at altitude and blocking fuel flow through an injection line. Is that correct? What was the temperature? Had you been hangared prior to that flight?
 
It wasn't just my Malibu.The freezing fuel line/ fuel nozzle issue has been an issue for a number of PA46-310P aircraft. I answer the MMOPA maintenance hotline and get the same story. Since 1984 we have added the alcohol to the fuel when worried about the issue in the winter. There has never been anything published about what to do.

I start using it when we start seeing -20 and below at altitude or when we had legs of 3 hrs or more at the flight levels. All it took is one event with my wife onboard. Being proactive and adding the alcohol made her feel better too and never saw another problem. I always filled my tanks outbound from KHUT with my own pumps. Also, our Malibu was always hangared.

Selling the KHUT shop and the kids more settled brought my use on N25LH down to 60 hrs the last year. So I sold it. I would still be using the same practice today.
 
NJP_MAN said:
Yea. They think is has biocide qualities and I have been told that is debatable. But they want us to always get fuel positive.
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Biocide is no longer a part of Prist, and hasent been for a long time. Patent issues.

They do coast on the idea that it still has biocide, and don't try to inform anyone to the contrary.
 
n20junkie said:
Biocide is no longer a part of Prist, and hasent been for a long time. Patent issues.

They do coast on the idea that it still has biocide, and don't try to inform anyone to the contrary.
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While not directly a biocide, I imagine it still does something since it and the organisms both go to the water within, I would suspect the chemistry of Prist is going to kill a few things.

It's not really an issue if you are flying a bunch, but for JetA if I was putting the plane away for awhile, I'd add some Biobor to the mix.
 
Henning said:
While not directly a biocide, I imagine it still does something since it and the organisms both go to the water within, I would suspect the chemistry of Prist is oing to kill a few things.

It's not really an issue if you are flying a bunch, but for JetA if I was putting the plane away for awhile, I'd add some Biobor to the mix.
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If it was a warm /hot climate I would too.....

West Marine probably has gallons in stock....
 
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