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The Importance of Fuel Injection in Backcountry Flying
The Importance of Fuel Injection in Backcountry Flying
For a long time, people have said a carbureted engine is preferable in a backcountry aviation setting. The adage goes something like "the complexity, weight, and hard starting of a fuel injection system is a disadvantage in the backcountry".
When I started seriously flying in a backcountry setting around a decade ago, I was open to this idea and keen to learn about it through experience. At the time, I hadn't committed to an engine choice for our aircraft. Trouble was, as I gained experience, it didn't align with the conventional wisdom. In fact, the opposite appeared to be true - older carbureted aircraft seemed to be less reliable, less capable, and tended to be operated at higher weights as they drank a lot more fuel. Evidence kept accruing over the years, all to the same tune. So I started to wonder, where has the conventional wisdom come from, and what changed since then. The following are my musings about this conundrum.
The Way It Was...
Back in the heyday of backcountry aviation, say 1950 to 1970, I am sure things were remarkably different:
- There was no common and personally portable way to jump-start a large aircraft engine - especially the larger 6 cylinder engines with heavy metal props to swing.
- Running engines lean of peak (LOP) not common practice or widely understood, so the fuel required was just a function of cubic inches.
- Reliance on electric gizmos in aircraft was still a relatively recent development, so the skills required to hand-start aircraft were still widespread
- Getting stuck in the backcountry could often become a dangerous survival situation. All-weather helicopter rescue, personal satellite communications, personal locator beacons (etc) were either uncommon, unaffordable, or impossible.
What's Changed?
Over 50 years of technology advances have dramatically improved the reality of backcountry flying. This has changed the game. In my observations, fuel injected aircraft now have a clear advantage over the alternatives. In some circumstances, the advantage is significant. At this point, I would acknowledge some people have an adverse reaction to relying on technology in the wilderness, but it has become reality. These days, few people go into backcountry settings without taking some technology for safety's sake. We all like a good backup plan.
The Advantages of Fuel Injection
- Running fuel injection means LOP operations are easy to do, giving considerably lower fuel burn and higher efficiency. Importantly, this means lighter operating weight and/or extended range at lighter weights. This is advantageous to all phases of the flight. It also more than offsets the extra weight of the fuel injection equipment installed. A plane with fuel injection can go further and land more easily at more challenging destinations early in the journey. Practically I have seen this constraint bind on many occasions, where non-FI aircraft needed additional return trips to uplift fuel, or to overfly landing areas due to weight.
- The importance of lighter weight operations is considerable. It drives safety, you can take more gear and be more prepared. You enjoy higher performance and greater safety margins. It means shorter ground roll and more control, meaning less risk exposure during what is certainly the most defining aspect of backcountry aviation - the backcountry landing. It also means you have more options for landing, shorter fields become accessible. Not to mention lower stress on the airframe if there's a heavy landing etc.
- Fuel injection generally delivers an extra ~5% excess horsepower, which (again) increases safety margins and performance, which is important as discussed above.
- The simplicity of operating the engine without needing carb heat, and the reduced risk from air intake icing. This is obviously not new, but it is important.
What about disadvantages?
- "The complexity myth" - yes it is a more complicated system, which needs electrical power. Practically I have seen any aircraft, regardless of engine configuration, are prone to break down. In my own experience, I have seen more carb planes stranded in the backcountry - perhaps because they are more common. I don't see any advantage to fuel injection here, but the rhetoric about this disadvantage seems relatively unfounded based on my limited and modern experiences. Perhaps things used to be different.
- "You need battery power to start" - the reality of modern electronic aircraft systems, like electric ignition, is that a flat battery or dull battery is no longer an issue restricted to fuel injection. Many aircraft engines have EI or other systems which require power, regardless of how fuel enters the cylinders. While this problem is only getting worse, the advent of modern lightweight batteries and jump packs means having a backup has never been easier. This has become non-issue, provided the pilot comes prepared.
- "You can't hand-prop with fuel injection" - when it comes to hand-starting a flat battery, especially when its unexpectedly and without regular practice - engines can be fickle. This is especially true of any large engine, particularly three blade carbon propellers which have little inertia and leave zero room for error. Pilots have to regularly practice hand starting their own aircraft to be assured they can hand-prop if required. They also need to know what they are doing, in case the engine is flooded. Most people tend to take other precautions instead, such as carrying a jump pack or satellite communications device. Again, this risk can be cheaply and easily managed these days - not so, 50 years ago.
Conclusions
Time and technology have addressed the disadvantages and created new ways to mitigate the risks.
In my opinion, which is biased, the fuel injected aircraft has a clear advantage in most operational aspects of backcountry flying. A direct comparison with other aircraft in a practical setting, makes this advantage apparent. At the least, I suggest we should temper the conventional wisdom with modern realities, when discussing the "benefits of a light, simple aircraft" for backcountry operations.
For a long time, people have said a carbureted engine is preferable in a backcountry aviation setting. The adage goes something like "the complexity, weight, and hard starting of a fuel injection system is a disadvantage in the backcountry".
When I started seriously flying in a backcountry setting around a decade ago, I was open to this idea and keen to learn about it through experience. At the time, I hadn't committed to an engine choice for our aircraft. Trouble was, as I gained experience, it didn't align with the conventional wisdom. In fact, the opposite appeared to be true - older carbureted aircraft seemed to be less reliable, less capable, and tended to be operated at higher weights as they drank a lot more fuel. Evidence kept accruing over the years, all to the same tune. So I started to wonder, where has the conventional wisdom come from, and what changed since then. The following are my musings about this conundrum.
The Way It Was...
Back in the heyday of backcountry aviation, say 1950 to 1970, I am sure things were remarkably different:
- There was no common and personally portable way to jump-start a large aircraft engine - especially the larger 6 cylinder engines with heavy metal props to swing.
- Running engines lean of peak (LOP) not common practice or widely understood, so the fuel required was just a function of cubic inches.
- Reliance on electric gizmos in aircraft was still a relatively recent development, so the skills required to hand-start aircraft were still widespread
- Getting stuck in the backcountry could often become a dangerous survival situation. All-weather helicopter rescue, personal satellite communications, personal locator beacons (etc) were either uncommon, unaffordable, or impossible.
What's Changed?
Over 50 years of technology advances have dramatically improved the reality of backcountry flying. This has changed the game. In my observations, fuel injected aircraft now have a clear advantage over the alternatives. In some circumstances, the advantage is significant. At this point, I would acknowledge some people have an adverse reaction to relying on technology in the wilderness, but it has become reality. These days, few people go into backcountry settings without taking some technology for safety's sake. We all like a good backup plan.
The Advantages of Fuel Injection
- Running fuel injection means LOP operations are easy to do, giving considerably lower fuel burn and higher efficiency. Importantly, this means lighter operating weight and/or extended range at lighter weights. This is advantageous to all phases of the flight. It also more than offsets the extra weight of the fuel injection equipment installed. A plane with fuel injection can go further and land more easily at more challenging destinations early in the journey. Practically I have seen this constraint bind on many occasions, where non-FI aircraft needed additional return trips to uplift fuel, or to overfly landing areas due to weight.
- The importance of lighter weight operations is considerable. It drives safety, you can take more gear and be more prepared. You enjoy higher performance and greater safety margins. It means shorter ground roll and more control, meaning less risk exposure during what is certainly the most defining aspect of backcountry aviation - the backcountry landing. It also means you have more options for landing, shorter fields become accessible. Not to mention lower stress on the airframe if there's a heavy landing etc.
- Fuel injection generally delivers an extra ~5% excess horsepower, which (again) increases safety margins and performance, which is important as discussed above.
- The simplicity of operating the engine without needing carb heat, and the reduced risk from air intake icing. This is obviously not new, but it is important.
What about disadvantages?
- "The complexity myth" - yes it is a more complicated system, which needs electrical power. Practically I have seen any aircraft, regardless of engine configuration, are prone to break down. In my own experience, I have seen more carb planes stranded in the backcountry - perhaps because they are more common. I don't see any advantage to fuel injection here, but the rhetoric about this disadvantage seems relatively unfounded based on my limited and modern experiences. Perhaps things used to be different.
- "You need battery power to start" - the reality of modern electronic aircraft systems, like electric ignition, is that a flat battery or dull battery is no longer an issue restricted to fuel injection. Many aircraft engines have EI or other systems which require power, regardless of how fuel enters the cylinders. While this problem is only getting worse, the advent of modern lightweight batteries and jump packs means having a backup has never been easier. This has become non-issue, provided the pilot comes prepared.
- "You can't hand-prop with fuel injection" - when it comes to hand-starting a flat battery, especially when its unexpectedly and without regular practice - engines can be fickle. This is especially true of any large engine, particularly three blade carbon propellers which have little inertia and leave zero room for error. Pilots have to regularly practice hand starting their own aircraft to be assured they can hand-prop if required. They also need to know what they are doing, in case the engine is flooded. Most people tend to take other precautions instead, such as carrying a jump pack or satellite communications device. Again, this risk can be cheaply and easily managed these days - not so, 50 years ago.
Conclusions
Time and technology have addressed the disadvantages and created new ways to mitigate the risks.
In my opinion, which is biased, the fuel injected aircraft has a clear advantage in most operational aspects of backcountry flying. A direct comparison with other aircraft in a practical setting, makes this advantage apparent. At the least, I suggest we should temper the conventional wisdom with modern realities, when discussing the "benefits of a light, simple aircraft" for backcountry operations.
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