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  #1  
Old 04-10-2021, 01:44 PM
mags591 mags591 is offline
 
Join Date: Jul 2020
Location: Bowie, MD
Posts: 7
Default Rotax 915iS in RV9

I know this was talked about a while ago, but I am wondering if there is anything more recent or if anyone has successfully made it happen?

Has anyone put a Rotax Engine (possibly the 915iS) in an RV9?

I have never used a Rotax engine but hear nothing but good things about them. Additionally, I love the idea of being able to use Mogas at several $$ less per gallon than 100LL. From what I have read, the 915iS is a powerful engine that could be a good power plant for the 9.

I am exploring options as I prepare my new RV9 build.

I appreciate all the comments.
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  #2  
Old 04-10-2021, 01:57 PM
YellowJacket RV9 YellowJacket RV9 is online now
 
Join Date: Oct 2012
Location: Clearwater, FL KCLW
Posts: 1,316
Default

I can run mogas in my 150HP O-320 no problem, and many others do as well. I'm sure the Rotax is a great engine but it's hard to beat the engine that the airframe was designed around. You may have issues with VNE as well with a turbocharged engine at altitude.

Chris
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RV-9A - Done(ish) 4/5/16! Flying 4/7/16
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  #3  
Old 04-10-2021, 07:15 PM
mags591 mags591 is offline
 
Join Date: Jul 2020
Location: Bowie, MD
Posts: 7
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Quote:
Originally Posted by YellowJacket RV9 View Post
I can run mogas in my 150HP O-320 no problem, and many others do as well. I'm sure the Rotax is a great engine but it's hard to beat the engine that the airframe was designed around. You may have issues with VNE as well with a turbocharged engine at altitude.

Chris
That is awesome. I was not aware of this. I will have to do some more research. I am a newbie when in the aviation world.

Do you need any sort of aftermarket modifications to do this or is the engine capable of burning Mogas from the factory? What is your performance like with the mogas vs. 100LL in the O-320?
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  #4  
Old 04-11-2021, 07:09 AM
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rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 5,931
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Lots of folks running mogas in Lycomings here on VAF...
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 445.9 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
https://www.youtube.com/channel/UCiy...g2GvQfelECCGoQ


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  #5  
Old 04-11-2021, 07:15 AM
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Vlad Vlad is online now
 
Join Date: Oct 2008
Location: Utah
Posts: 8,315
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Quote:
Originally Posted by rv6ejguy View Post
Lots of folks running mogas in Lycomings here on VAF...
Some of them ethanol laced 87
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Не имей сто рублей, а имей сто друзей.
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  #6  
Old 04-11-2021, 12:10 PM
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airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,381
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I'm running ethanol laced 91 in my IO-360, almost 800 hours in the last 5 years.
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Garden City, TX VAF 2021 dues paid
N16GN flying 750 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, IFD440
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
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  #7  
Old 04-11-2021, 12:19 PM
uk_RV9A uk_RV9A is offline
 
Join Date: Jan 2013
Location: UK
Posts: 22
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Are the fuel pump and fuel injector materials on the io- lycomings OK to use with ethanol laced fuel?
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  #8  
Old 04-11-2021, 04:07 PM
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9GT 9GT is offline
 
Join Date: Jan 2010
Location: Southern Michigan
Posts: 2,105
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You will have no problems running mogas in the O-320/IO-320 Lycoming's as long as you have low compression pistons. I always kept a tank of 90 octane ethanol free "recreation gas" in my IO-540 powered RV-10 and never an issue. I'll be running it in my -9A also. I think the Rotax would be severely under-powering a -9.
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RV-10: #41686 Under Construction
RV-9A: #90949 Under Construction
RV-10: #40637 Completed/Sold 2016
Cozy MKIV:#656 Completed/Sold 2007
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  #9  
Old 04-11-2021, 05:00 PM
munbro01 munbro01 is offline
 
Join Date: Aug 2019
Location: Mabank, TX
Posts: 30
Default Re: Mogas

The Rotax from what Iíve read will accept 91+ octane auto fuel. But to be clear Mogas is NOT your everyday automotive gas from your local gas station. It is Ethanol FREE. 87 octane is most readily available, the largest distributer here in Texas is Murphy Oil (Walmart). 91 + can be found near or at Marinas or Farm/Ranch stores.
Petersen Avation sell the Mogas STC for about $200 and Ethanol tester $15. EAA also offers?

On a new engine, after first 100 hrs of 100LL, we mix 87 Ethanol Free with 100 LL (80:20) on a C85. A Lycoming O320/150 will accept the 87+ per the STC.

Other than cost, youíll realize reduced maintenance cost in spark plugs and dirty oil.

Hope this helps
Bill
A&P
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  #10  
Old 04-22-2021, 09:41 PM
NordicDave NordicDave is offline
 
Join Date: Oct 2020
Location: KSNS
Posts: 19
Default

Quote:
Originally Posted by YellowJacket RV9 View Post
I'm sure the Rotax is a great engine but it's hard to beat the engine that the airframe was designed around.
Chris
The new Rotax 918is at 231HP otta get the job done.
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