frazitl
Well Known Member
I sent a couple questions to Precision about their Silverhawk FI servo and it's compatibility with Ethanol (E10) laced mogas. I was under the impression that their servo was not compatible with E10, but the bottom line is it's not a problem except for any corrosion that might result from long term storage. See my questions and their replies below. 
Question to Precision 4/19/12:
I've heard that the silverhawk fuel injection system is not approved for auto fuel with 10% or less methanol (EDIT: my bad, I was thinking Ethanol and asked about Methanol). Can't find any fuel quality references on your site. Are there any components of the current SilverHawk system that can not tolerate 10% or less methanol (EDIT: Ethanol)?
Answer from Precision:
Don't know much about methanol except it's more corrosive than ethanol. I can tell you the Brazilians use 100% ethanol in our fuel injection systems and after several years they have seen some corrosion issues internally but they continue to use it. You might get hold of Baylor university as they are experimenting with Methanol. I don't have any contact information for them. You would have to search to find out exactly who to contact. Superior does approve the use of high octane auto gas in our Silver Hawk systems. Hope this information helps you. Have a nice day.
Alan Jesmer,
Precision Airmotive LLC
My follow-up question:
Thanks for your quick reply. I was in error when I asked about methanol. I am really interested in any negative effects of ethanol (E10) on the Silverhawk. I'm looking at eliminating the mechanical fuel pump (non E10
compliant) and running two electric E10 compliant fuel pumps with redundant electrical supplies so that I can run E10 in my Superior engine. Best I can tell if the SilverHawk is OK with E10, than I'm good to go. Many builders are running with one tank of 100LL and one tank with E10. To mitigate any corrosion, vapor pressure, or compatibility issues, they are sure to run the engine in the pattern on the 100LL tank for both takeoff and landing.
Sounds like the Brazilian experience would support this approach. If you could as a company support this type of operation for experimental use, I'm sure you would make some gains in market share. An alternate might be a shorter TBO for such operation so you could gather in service info for future blanket E10 endorsement. Any chance of some sort of official guidance by Precision on this?
BTW, Superior approves high octane mogas for their standard compression ratio engine, but with the stipulation of NO ethanol. May just be due to the mechanical pump... No ethanol fuel is impossible to get in most areas of the country.
Thanks in advance,
Terry
Precision Answer 4/20/12:
Hi Terry,
As you stated with Superior, Lycoming and Continental, as well as the STCs available for auto fuel use with certified aircraft specifically forbid alcohol content. And while there are no components in the Precision Silver Hawk fuel system which would be attacked by Ethanol, the use of fuel containing Ethanol will increase the likely hood of corrosion in the system. In order to reduce this, I would recommend not leaving fuel containing Ethanol sitting in the aircraft for any extended periods. If the aircraft will be parked for more than a week or so, it would be a good idea to empty the tanks of the Ethanol fuel and refill with and run 100LL through the system.
Regards,
Peter Nielson
Product Support Mgr.
Precision Airmotive LLC
Question to Precision 4/19/12:
I've heard that the silverhawk fuel injection system is not approved for auto fuel with 10% or less methanol (EDIT: my bad, I was thinking Ethanol and asked about Methanol). Can't find any fuel quality references on your site. Are there any components of the current SilverHawk system that can not tolerate 10% or less methanol (EDIT: Ethanol)?
Answer from Precision:
Don't know much about methanol except it's more corrosive than ethanol. I can tell you the Brazilians use 100% ethanol in our fuel injection systems and after several years they have seen some corrosion issues internally but they continue to use it. You might get hold of Baylor university as they are experimenting with Methanol. I don't have any contact information for them. You would have to search to find out exactly who to contact. Superior does approve the use of high octane auto gas in our Silver Hawk systems. Hope this information helps you. Have a nice day.
Alan Jesmer,
Precision Airmotive LLC
My follow-up question:
Thanks for your quick reply. I was in error when I asked about methanol. I am really interested in any negative effects of ethanol (E10) on the Silverhawk. I'm looking at eliminating the mechanical fuel pump (non E10
compliant) and running two electric E10 compliant fuel pumps with redundant electrical supplies so that I can run E10 in my Superior engine. Best I can tell if the SilverHawk is OK with E10, than I'm good to go. Many builders are running with one tank of 100LL and one tank with E10. To mitigate any corrosion, vapor pressure, or compatibility issues, they are sure to run the engine in the pattern on the 100LL tank for both takeoff and landing.
Sounds like the Brazilian experience would support this approach. If you could as a company support this type of operation for experimental use, I'm sure you would make some gains in market share. An alternate might be a shorter TBO for such operation so you could gather in service info for future blanket E10 endorsement. Any chance of some sort of official guidance by Precision on this?
BTW, Superior approves high octane mogas for their standard compression ratio engine, but with the stipulation of NO ethanol. May just be due to the mechanical pump... No ethanol fuel is impossible to get in most areas of the country.
Thanks in advance,
Terry
Precision Answer 4/20/12:
Hi Terry,
As you stated with Superior, Lycoming and Continental, as well as the STCs available for auto fuel use with certified aircraft specifically forbid alcohol content. And while there are no components in the Precision Silver Hawk fuel system which would be attacked by Ethanol, the use of fuel containing Ethanol will increase the likely hood of corrosion in the system. In order to reduce this, I would recommend not leaving fuel containing Ethanol sitting in the aircraft for any extended periods. If the aircraft will be parked for more than a week or so, it would be a good idea to empty the tanks of the Ethanol fuel and refill with and run 100LL through the system.
Regards,
Peter Nielson
Product Support Mgr.
Precision Airmotive LLC
