Huh, that's interesting thanks for the link!
Here is a much deeper look at the history and some of the early research and aviation user data.
A bit long but a lot of good information.
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Huh, that's interesting thanks for the link!
Here is a much deeper look at the history and some of the early research and aviation user data.
A bit long but a lot of good information.
If an in tank pump fails, you can't access the fuel in that tank. The current pump life is excellent and vapor lock hasn't been an issue if proper location and plumbing practices are followed.
We strongly recommend that people use what's been proven over a half million flight hours with regards to the EFI fuel system if you don't want surprises or to be on a test program to validate a new design.
And yeah I get the "don't rock the boat" comment. I was just curious if anyone had tried dual in-tank pumps in an aircraft before.
You could use a venturi-style cross-draw setup in the event of a pump failure in one wing. This setup has been standard practice in automotive applications that have the fuel tank straddle the driveshaft hump for some 20 years now.
It would make plumbing slightly more difficult and it would be a lot harder to change a pump in the event of a failure but no more difficult than a bad fuel sending unit.
And yeah I get the "don't rock the boat" comment. I was just curious if anyone had tried dual in-tank pumps in an aircraft before.
I'm not understanding what you're describing here. If you have one pump in each tank and the pump fails, you can't get at the rest of the fuel in that tank.
In aviation, once we have demonstrated the reliability of a layout or system, we repeat that without deviation to get the same results over and over.
If you want to put pumps in the tanks, you could. I've just outlined the main reason it's not done. We have a proven, very reliable layout now with few drawbacks. I'm not sure why it would be a good idea to change that. What would be the advantage over the existing layout?
Same as motive flow? Motive flow is used in fuel tanks of most biz jets I'm familiar with.
Here's a basic description I found.
https://aviation.stackexchange.com/questions/34301/what-is-motive-flow-and-why-is-it-used-in-some-aircraft-hydraulic-systems
Yes. You'd use the motive flow to move fuel from the dead tank to the active tank in the event of a pump failure. In a dual-pump situation both pumps would be moving fuel equally and would cancel each other out (or you would have pressure valves that prevent the cross-flow in equilibrium).
Do not stress.
The PAFI process was fatally flawed right from the beginning. Recently proven.
There is a certification project almost complete and has taken time due funding and apathy of the market to get behind it, but is literally "months" or "weeks" from a major milestone.
G100UL is the likely fuel you will have when the time comes. So relax. Build on.
Most recent AOPA article on 100LL replacement. EAA had a similar article.
Shell developed a really cool new paint stripper. SWIFT won't start in Winter or if you brew it synthetically the components cost north of $12/gal before you get started. And it didn't work (not when my data source was current).
Neither is fungible with the existing avgas. At some point you need to have a changeover period and a long and lengthy one at that.
One fuel does tick all the boxes and does better in some areas than current 100LL., and it was never part of the fatal flawed PAFI project. Make of that what you will. And just because one company is huge and has large cash sources does not mean that they can or will solve the problem. They haven't.
Yes, but the difference now is that there is a growing number of mostly non-aviation folks who want all the lead out of all gasoline due to environmental concerns, and have sued to accomplish that goal.
Does anybody have the accurate records for the make up of 130 Octane gasoline that was used in the 1940's when Mustangs, Spits and other merlin powered AC used it?
Does anybody have the accurate records for the make up of 130 Octane gasoline that was used in the 1940's when Mustangs, Spits and other merlin powered AC used it?
Isn't it *still* used by the air racers?
For those interested, here's the latest update from the FAA on the 100LL replacement program (PAFI).
https://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=14754
Maybe some of our colonial brothers from accross
the pond would chime in here. A few years ago in
Great Britain they allowed you to burn ?auto fuel ?
in several types of aircraft. One of the restrictions
was not flying above ?4000 ft. Run down to your
neighbor hood gas station fuel up and take off in
the summer months then climb up to cool off and
you would be surprised how many people encounter
ruff running engine problems that are probably the
onset of vapor lock problems.
Greg, some of our friends in Oz have seen some serious valve seat problems operating on mogas in a fraction of the time you have. Apparently Swift put an additive in their UL fuels to mitigate this problem.
Any indication from leakdown and borescope tests that you are seeing these effects?
Very curious.
Looks like the program is in high-speed neutral, just as expected.
The goal of the PAFI program is literally impossible - trying to please everyone. You're never going to get there. They need to make a fuel that is a drop-in replacement for ALL engines in ALL applications, and at a price that is equal or lower than current fuel, and all that in as short a time as possible.
It was doomed to failure before the politicians even picked up the scent.
I believe that 100LL will eventually go away - but it will not be possible, EVER, to do so easily or painlessly. That's just part of life.
Shawn,
This is a more philosophical answer to your comment about having the 100LL dilemma taking the wind out of your sails. So, if you are looking for more technical response, skip to the next post.
Ten years ago I was just finishing my RV-8 tail kit while working for a major manufacturer of piston aircraft and business jets. I was in a meeting with the CEO of one of the largest distributors of avgas and jet fuel in the U.S., and left the meeting convinced that 100LL would either be gone, or cost $50 per gallon in the near future. It definitely took the wind out of my building sails, so I finished my empennage and boxed the pieces up for storage.
Fast forward 10 years to today, and 100LL is still available and at a reasonable cost. If I had kept building, I might be flying by now.
As I'm sure many people in their 50s do, I stopped to think about what is really important in life and what I want to accomplish with the fewer years I have ahead of me. Aviation has been a core element in my life since I was a child, but without an airplane of my own, I feel like I have not fully enjoyed or committed to my passion.
But what about 100LL in the future? I don't know, but I do know that in 20 years I definitely don't want to look back and regret giving up on my dream of building and flying my own airplane.
So, I just took delivery of the wing kit for my RV-8.
And, while I still choke on the thought of spending $30k on a new Lycoming, that purchase is still probably a decade off for me, and I will continue to build on faith. Faith that some type of powerplant and fuel will be available when I finish. It might be 100LL, it might be 94UL, it might be Jet-A. And I am watching the electric propulsion developments very closely.
We probably won't see the flux capacitor from Back to the Future in our lifetimes, but I do have faith that technology and market opportunity will come together to give us some way to keep flying these wonderful machines.
Build on!
Tom