4 ms·

What is the biggest drawback of G100UL? Usually when something is this hung up, its because the two sides disagree on the magnitude of a specific or small set

What is the biggest drawback of G100UL? Usually when something is this hung up, its because the two sides disagree on the magnitude of a specific or small set of problems. I can't help but feel that this article is leaving out a key detail.

jpgvm 5y ago
Cost, the article says approx 50-85c more per gallon.
- londons_explore 5y ago
  Which is peanuts compared to the economic cost of distributing lead into everyone's lungs and waterways... But somehow it's the 85 cents a gallon everyone's worried about, not the tens of billions of dollars...
  - deleted 5y ago
    [deleted]
- stefan_ 5y ago
  As the comments note, however, unleaded gas will not cause lead deposits in the engine and can therefore reduce maintenance required and extend maintenance intervals.
  - robonerd 5y ago
    This is unlikely to be a major factor for aircraft engines, which need to be serviced regularly anyway (long before lead deposits would force it.)
  - NovemberWhiskey 5y ago
    In my experience, "lead deposits" are basically an issue caused by running excessively rich mixture, usually on the ground, and show up as spark plug fouling with engine roughness and reduced RPMs. The fix is just to vaporize the deposits by running the engine at leaner and at a high power setting. I understand that you can also end up with exhaust valve deposits, but that's not something I've seen personally. Aviation engines (especially those used for training, which is a large proportion of the piston fleet) have incredibly short inspection intervals in any case.
- mario_kart_snes 5y ago
  What's the current price per gallon?
  - DaiPlusPlus 5y ago
    According to http://www.100ll.com/ http://www.100ll.com/ - about $6.00 to $6.70 at retail. Looking at my own local airports ( e.g. http://www.100ll.com/showfbo.php?HashID=d0f7e0afbdcf9b9a7cdea686d5a7c8e5 http://www.100ll.com/showfbo.php?HashID=d0f7e0afbdcf9b9a7cde... ) the price goes higher to often over $7.00/gal, though that's for "full service" (I don't know what that means, though).
    - sokoloff 5y ago
      Full-service just means it's dispensed by an employee rather than by the pilot. (The practical implication is "you can buy fuel only when the business selling fuel is open, or pay a call-out fee".) This could be dispensed from a fuel truck (most common for full-serve) or from a pump. Self-service means there's a pump with a credit card and a really long hose, that would look familiar to what you see at an auto filling station.
  - FL410 5y ago
    You don't want to know. Somewhere between $5-10/gallon. Normal times, $3.50-7/gallon.
sokoloff 5y ago
I'm a very strong believer in G100UL being the best future piston aviation fuel and have a lot of trust in the engineering and lab work that GAMI has done here. The biggest drawback IMO is "there's no question that 100LL is a safe and reliable fuel operationally; it's been proven over a 50-year period; G100UL has significantly fewer operational hours in its history." I could not care less about any sub-20% difference in retail price. Very few pilots paying out of their own pocket fly over 100 hours per year. $0.85/gallon increase in cost represents less than $1000/yr difference for reasonably high-utilization recreational/private pilots. Even for higher utilization operators, fuel is around 25-40% of the total annual costs of a piston aircraft. A 20% increase in price of fuel represents a modest change in overall annual costs.
- bombcar 5y ago
  It sounds like what's needed is a way to get more operational hours in a way that satisfies the paper-pushers. Allowing it on one engine of multi-prop planes might work if it weren't for the fact that those usually mix tanks ...
iamtheworstdev 5y ago
The drawback is liability - in order for this to work, the FAA has to blanket say "G100UL is allowed to replace 100LL". And if it doesn't go well, then it's on the FAA for having let it happen. The price increase is also key and we're working on two assumptions - That GAMI isn't lying and the price increase will only by what they say, and that engine maintenance will in fact be less. Because it's already expensive for a person to train to become an airline pilot and this will make it worse as we head into an extreme pilot shortage in the near future. There's also a fact that no one likes - the level of lead pollution coming from this is pretty minor. I know we all want to be "no lead ever!" but, as someone posted earlier, the amount of lead a person ends up exposed to when they are neighbors with an airport is nowhere near a level that's considered harmful to any extent. And if battery powered everything is going to start taking over general aviation, along with aviation diesel motors that can run jet fuel, then what's the rush to replace 100LL. It's on a limited timeline already. Could be worse, though. They could be trying to force ethanol on us.
- GordonS 5y ago
  > And if battery powered everything is going to start taking over general aviation I think we're a long way off even small electric planes starting to take over, at least a decade. And given the lifetime of planes, it'll be several more decades before they overtake combustion planes - and they may never do so for large aircraft because of battery energy density and weight.

jpgvm 5y ago

Cost, the article says approx 50-85c more per gallon.

londons_explore 5y ago
Which is peanuts compared to the economic cost of distributing lead into everyone's lungs and waterways... But somehow it's the 85 cents a gallon everyone's worried about, not the tens of billions of dollars...
- deleted 5y ago
  [deleted]
stefan_ 5y ago
As the comments note, however, unleaded gas will not cause lead deposits in the engine and can therefore reduce maintenance required and extend maintenance intervals.
- robonerd 5y ago
  This is unlikely to be a major factor for aircraft engines, which need to be serviced regularly anyway (long before lead deposits would force it.)
- NovemberWhiskey 5y ago
  In my experience, "lead deposits" are basically an issue caused by running excessively rich mixture, usually on the ground, and show up as spark plug fouling with engine roughness and reduced RPMs. The fix is just to vaporize the deposits by running the engine at leaner and at a high power setting. I understand that you can also end up with exhaust valve deposits, but that's not something I've seen personally. Aviation engines (especially those used for training, which is a large proportion of the piston fleet) have incredibly short inspection intervals in any case.
mario_kart_snes 5y ago
What's the current price per gallon?
- DaiPlusPlus 5y ago
  According to http://www.100ll.com/ http://www.100ll.com/ - about $6.00 to $6.70 at retail. Looking at my own local airports ( e.g. http://www.100ll.com/showfbo.php?HashID=d0f7e0afbdcf9b9a7cdea686d5a7c8e5 http://www.100ll.com/showfbo.php?HashID=d0f7e0afbdcf9b9a7cde... ) the price goes higher to often over $7.00/gal, though that's for "full service" (I don't know what that means, though).
  - sokoloff 5y ago
    Full-service just means it's dispensed by an employee rather than by the pilot. (The practical implication is "you can buy fuel only when the business selling fuel is open, or pay a call-out fee".) This could be dispensed from a fuel truck (most common for full-serve) or from a pump. Self-service means there's a pump with a credit card and a really long hose, that would look familiar to what you see at an auto filling station.
- FL410 5y ago
  You don't want to know. Somewhere between $5-10/gallon. Normal times, $3.50-7/gallon.

sokoloff 5y ago

I'm a very strong believer in G100UL being the best future piston aviation fuel and have a lot of trust in the engineering and lab work that GAMI has done here. The biggest drawback IMO is "there's no question that 100LL is a safe and reliable fuel operationally; it's been proven over a 50-year period; G100UL has significantly fewer operational hours in its history." I could not care less about any sub-20% difference in retail price. Very few pilots paying out of their own pocket fly over 100 hours per year. $0.85/gallon increase in cost represents less than $1000/yr difference for reasonably high-utilization recreational/private pilots. Even for higher utilization operators, fuel is around 25-40% of the total annual costs of a piston aircraft. A 20% increase in price of fuel represents a modest change in overall annual costs.

bombcar 5y ago
It sounds like what's needed is a way to get more operational hours in a way that satisfies the paper-pushers. Allowing it on one engine of multi-prop planes might work if it weren't for the fact that those usually mix tanks ...

iamtheworstdev 5y ago

The drawback is liability - in order for this to work, the FAA has to blanket say "G100UL is allowed to replace 100LL". And if it doesn't go well, then it's on the FAA for having let it happen. The price increase is also key and we're working on two assumptions - That GAMI isn't lying and the price increase will only by what they say, and that engine maintenance will in fact be less. Because it's already expensive for a person to train to become an airline pilot and this will make it worse as we head into an extreme pilot shortage in the near future. There's also a fact that no one likes - the level of lead pollution coming from this is pretty minor. I know we all want to be "no lead ever!" but, as someone posted earlier, the amount of lead a person ends up exposed to when they are neighbors with an airport is nowhere near a level that's considered harmful to any extent. And if battery powered everything is going to start taking over general aviation, along with aviation diesel motors that can run jet fuel, then what's the rush to replace 100LL. It's on a limited timeline already. Could be worse, though. They could be trying to force ethanol on us.

GordonS 5y ago
> And if battery powered everything is going to start taking over general aviation I think we're a long way off even small electric planes starting to take over, at least a decade. And given the lifetime of planes, it'll be several more decades before they overtake combustion planes - and they may never do so for large aircraft because of battery energy density and weight.