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Alternate Fuel for 914

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AmphibFlyer

Joined: 29 Dec 2009
Posts: 25

Posted: Thu Jan 17, 2013 4:44 pm Post subject: Alternate Fuel for 914

Does anyone know whether it's feasible to operate a Rotax 914 on regular-grade MOGAS in countries where premium and 100LL are not available? (I know that Rotax specifies 91 octane or better.)

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Thu Jan 17, 2013 8:04 pm Post subject: Re: Alternate Fuel for 914

91 oct. or higher or 100LL is the only choice. Use of 87 Oct will cause damage to the engine. If you have planes in a country seems like they should have at least 100LL.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

davidjoyce(at)doctors.org
Guest

Posted: Fri Jan 18, 2013 12:50 am Post subject: Alternate Fuel for 914

I have flown my 914 powered Europa all round Europe 

(around 30 countries) using Mogas. In Austria & Germany 

where Rotax engines are especially common something like 

half of all airfields have Mogas on sale. Always use the 

lower grade version rather Han the super grade. Regards, 

David Joyce



On Thu, 17 Jan 2013 16:44:26 -0800

  "AmphibFlyer" <SeaRey(at)AbstractConcreteWorks.com> wrote:

 	  Quote: 	
		   

<SeaRey(at)AbstractConcreteWorks.com>

 

 Does anyone know whether it's feasible to operate a 

Rotax 914 on regular-grade MOGAS in countries where 

premium and 100LL are not available? (I know that Rotax 

specifies 91 octane or better.)

 

 

 

 

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Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Fri Jan 18, 2013 6:09 am Post subject: Re: Alternate Fuel for 914

Be careful with the term Mogas. It usually means auto fuel for aviation and has nothing to do with the octane rating. Most airports that carry Mogas in the US use 87 Oct., but some have up to 93.

87 could easily cause detonation in a 914 or 912ULS. I have seen the damage a couple of times and it happens so quick there is no saving the engine and it is quite expensive. The 912UL is good with 87 oct.

This all boils down to the compression ratio between the 912UL verses the compression in the 914 and 912ULS.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

pjeffers(at)talktalk.net
Guest

Posted: Fri Jan 18, 2013 8:38 am Post subject: Alternate Fuel for 914

Roger,  

   

I note your comments re octane rating and Mogas.  I thought the compression ratio of the 912ul is the same as the 914.  Only the 912s is different, ie higher.  

   

Pete Jeffers           

    

    

                        

[img]cid:image001.gif(at)01CDF59A.2FCAF010[/img]Posted: Fri Jan 18, 2013 6:09 am        Post subject: Re: Alternate Fuel for 914               

[img]cid:image002.gif(at)01CDF59A.2FCAF010[/img]                                 

     

                       

Be     careful with the term Mogas. It usually means auto fuel for aviation and     has nothing to do with the octane rating. Most airports that carry Mogas in     the US     use 87 Oct., but some have up to 93. 

     87     could easily cause detonation in a 914 or 912ULS. I have seen the damage a     couple of times and it happens so quick there is no saving the engine and     it is quite expensive. The 912UL is good with 87 oct. 

     This     all boils down to the compression ratio between the 912UL verses the     compression in the 914 and 912ULS.               

        

   

   

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rlborger(at)mac.com
Guest

Posted: Fri Jan 18, 2013 8:58 am Post subject: Alternate Fuel for 914

Pete,



The turbo crams more air into the cylinder and the air is compressed so it's hot air.  The combination of a greater volume of hot air makes the effective compression ratio much higher than it would appear from just looking at the swept volume of the cylinder divided by unswept volume.  Also, because the air is compressed and hot, this further enhances the chances for detonation.  You MUST use high octane fuel, minimum 91 octane or higher.  You do not want to encounter detonation in that expensive 914 as it will destroy the engine very quickly.



 Blue skies & tailwinds,

Bob Borger

Europa XS Tri, Rotax 914, Airmaster C/S Prop.

Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP

3705 Lynchburg Dr.

Corinth, TX  76208-5331

Cel: 817-992-1117

rlborger(at)mac.com (rlborger(at)mac.com)



 

 

On Jan 18, 2013, at 10:38 AM, Peter Jeffers <pjeffers(at)talktalk.net (pjeffers(at)talktalk.net)> wrote:

       v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);}  <![endif]-->        st1\:*{behavior:url(#default#ieooui) }  <![endif]-->       <![endif]-->       <![endif]-->     

Roger,

 

I note your comments re octane rating and Mogas.  I thought the compression ratio of the 912ul is the same as the 914.  Only the 912s is different, ie higher.

 

Pete Jeffers        

 

 

                   

<image001.gif>Posted: Fri Jan 18, 2013 6:09 am        Post subject: Re: Alternate Fuel for 914          

<image002.gif>                                 



                  

Be     careful with the term Mogas. It usually means auto fuel for aviation and     has nothing to do with the octane rating. Most airports that carry Mogas in     the US     use 87 Oct., but some have up to 93. 

     87     could easily cause detonation in a 914 or 912ULS. I have seen the damage a     couple of times and it happens so quick there is no saving the engine and     it is quite expensive. The 912UL is good with 87 oct. 

     This     all boils down to the compression ratio between the 912UL verses the     compression in the 914 and 912ULS.            

      

 

 

--

Alan Carter

Joined: 02 Jul 2012
Posts: 378
Location: Kent, England.

Posted: Fri Jan 18, 2013 2:04 pm Post subject: Re: Alternate Fuel for 914

Hello Roger,Peter,and All.

I turn the key on my car and it starts, turn the key on a Cessna 150 and it starts,  i use to flip the switch on 4 jet engines and they started.

I keep being told how good the Rotax engine is but it always seems to have problems.!!!

This dreaded Detonation and kicking back seems to cause havoc on Rotax engines,Sprag clutches, Soft Starts, Oversized Starters,Fuels,ete.

Is cold weather i have a fully charged battery plus hook up to my motor cycle battery as well, i am using Mogas super think it about 91,yet i get this dreaded kicking back, i have seen the propeller oscillate it knocks hell out of the engine. My point is this should not be happening why was it not sorted out by Rotax long ago.

I guess a high spin rate and power enough to give engine no choice in the direction its going to turn.

We have Super plus in the UK think its about 94 or 96,Octane, and think also has NO ethanol. However the CAA have dreamed up something about vapour locking, probable some bod has read about vapour locking but i bet there's never been any actual tests carried out.

Its about -5 at the moment bloody cold. Vapour more like freezing of the fuel, really have no idea of the temp which fuel freezes all i know i won,t be up there. 

How would you set about starting a 914 to lessen the chance of kick back.

Regards 

Alan

davidjoyce(at)doctors.org
Guest

Posted: Fri Jan 18, 2013 2:39 pm Post subject: Alternate Fuel for 914

Alan, Kick back is something I associate with 912S engines 

rather than 914 s. Mine has always started pretty much 

first time on any old Mogas or Avgas with no hint of kick 

back. I just wonder whether it is a question of how well 

your engine turns over  and wonder what sort of battery 

you have. I am helping supervise our local School's Build 

a Plane project of a Rans with a Jabiru engine. We have 

got to the engine trials stage and we found the brand new 

fully charged battery supplied would only just turn the 

engine over at about a blade every 15 secs. We complained 

and the suppliers sent another with the same result. We 

went over the battery circuit polishing everything, but no 

different. In exasperation I went and took the Odyssey 

p680 battery out of my plane and tried that. It was in a 

midwinter state not having been charged for a fair time, 

and it was identical size to the one they supplied. 

However it turned the engine over like a windmill in a 

gale!

      Checking on line we found that the supplied battery 

was a cheap affair designed for golf buggies whereas the 

Odyssey is a pure lead, gas recombinant type with 

negligible internal resistance and massive cranking power. 

Regards, David Joyce, G- XSDJ



On Fri, 18 Jan 2013 14:04:36 -0800

  "Alan Carter" <alancarteresq(at)onetel.net> wrote:

 	  Quote: 	
		   

<alancarteresq(at)onetel.net>

 

 Hello Roger,Peter,and All.

 I turn the key on my car and it starts, turn the key on 

a Cessna 150 and it starts,  i use to flip the switch on 

4 jet engines and they started.

 I keep being told how good the Rotax engine is but it 

always seems to have problems.!!!

 This dreaded Detonation and kicking back seems to cause 

havoc on Rotax engines,Sprag clutches, Soft Starts, 

Oversized Starters,Fuels,ete.

 Is cold weather i have a fully charged battery plus hook 

up to my motor cycle battery as well, i am using Mogas 

super think it about 91,yet i get this dreaded kicking 

back, i have seen the propeller oscillate it knocks hell 

out of the engine. My point is this should not be 

happening why was it not sorted out by Rotax long ago.

 I guess a high spin rate and power enough to give engine 

no choice in the direction its going to turn.

 We have Super plus in the UK think its about 94 or 

96,Octane, and think also has NO ethanol. However the CAA 

have dreamed up something about vapour locking, probable 

some bod has read about vapour locking but i bet there's 

never been any actual tests carried out.

 Its about -5 at the moment bloody cold. Vapour more like 

freezing of the fuel, really have no idea of the temp 

which fuel freezes all i know i won,t be up there. 

 How would you set about starting a 914 to lessen the 

chance of kick back.

 Regards 

 Alan

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=392604#392604

 

 

 

 

 

 

 

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rlborger(at)mac.com
Guest

Posted: Fri Jan 18, 2013 2:44 pm Post subject: Alternate Fuel for 914

Alan,



I'm not sure where to start because with my 914 it's: 1) I turn on the master, 2) flip on the two ignition switches, 3) flip on the electric boost pump to get fuel pressure and 4) flip it off, 5) pull on the "Choke" if it's cool to cold, 6) flip on the starter and 7) it starts.  Every time.  No kickback ever.  Start is usually on one blade passing in the summer, two or, maybe, three blades in the winter if it's really cold. Coldest start has been -2ºC in a north Texas winter.  Any colder than that (it can get to -20ºC or lower) and I'm not going to the airport.  



Caveats:

Only 30 hours so far but I'm working on that.  Now this is with the, expen$ive, upgraded starter which was installed prior ever starting the engine.  And I only use 100LL.  No MoGas as MoGas is not available at airports in my area nor in the areas where I usually fly.  So to keep things simple, I only use 100LL.  This has been with the recommended Mobil 1 Motorcycle Oil.  But it's not supposed to be used with 100LL, so I'm switching to AeroShell Sport next month when I do the annual.  We'll see if that changes anything.



Blue skies & tailwinds,

Bob Borger

Europa XS Tri, Rotax 914, Airmaster C/S Prop.

Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP

3705 Lynchburg Dr.

Corinth, TX  76208-5331

Cel: 817-992-1117

rlborger(at)mac.com



On Jan 18, 2013, at 4:04 PM, Alan Carter <alancarteresq(at)onetel.net> wrote:






Hello Roger,Peter,and All.

I turn the key on my car and it starts, turn the key on a Cessna 150 and it starts,  i use to flip the switch on 4 jet engines and they started.

I keep being told how good the Rotax engine is but it always seems to have problems.!!!

This dreaded Detonation and kicking back seems to cause havoc on Rotax engines,Sprag clutches, Soft Starts, Oversized Starters,Fuels,ete.

Is cold weather i have a fully charged battery plus hook up to my motor cycle battery as well, i am using Mogas super think it about 91,yet i get this dreaded kicking back, i have seen the propeller oscillate it knocks hell out of the engine. My point is this should not be happening why was it not sorted out by Rotax long ago.

I guess a high spin rate and power enough to give engine no choice in the direction its going to turn.

We have Super plus in the UK think its about 94 or 96,Octane, and think also has NO ethanol. However the CAA have dreamed up something about vapour locking, probable some bod has read about vapour locking but i bet there's never been any actual tests carried out.

Its about -5 at the moment bloody cold. Vapour more like freezing of the fuel, really have no idea of the temp which fuel freezes all i know i won,t be up there. 

How would you set about starting a 914 to lessen the chance of kick back.

Regards 

Alan

rlborger(at)mac.com
Guest

Posted: Fri Jan 18, 2013 2:52 pm Post subject: Alternate Fuel for 914

Alan,



After reading David's post, I need to add that this is primarily with an Odyssey PC680 which is kept on a battery charger/maintainer.  And the aircraft is hangered 100% of the time it's not flying.  I recently (like 2 hours flying time ago) switched the PC680 for an AeroVoltz LiFePo battery which is 12 lbs lighter and seems to start it just as readily but doesn't have the long-term juice to run the electrics for more than about 20 minutes or so.  Can't recommend it at all to electrically dependent engines.



Blue skies & tailwinds,

Bob Borger

Europa XS Tri, Rotax 914, Airmaster C/S Prop.

Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP

3705 Lynchburg Dr.

Corinth, TX  76208-5331

Cel: 817-992-1117

rlborger(at)mac.com



On Jan 18, 2013, at 4:44 PM, Robert Borger <rlborger(at)mac.com> wrote:



Alan,



I'm not sure where to start because with my 914 it's: 1) I turn on the master, 2) flip on the two ignition switches, 3) flip on the electric boost pump to get fuel pressure and 4) flip it off, 5) pull on the "Choke" if it's cool to cold, 6) flip on the starter and 7) it starts.  Every time.  No kickback ever.  Start is usually on one blade passing in the summer, two or, maybe, three blades in the winter if it's really cold. Coldest start has been -2ºC in a north Texas winter.  Any colder than that (it can get to -20ºC or lower) and I'm not going to the airport.  



Caveats:

Only 30 hours so far but I'm working on that.  Now this is with the, expen$ive, upgraded starter which was installed prior ever starting the engine.  And I only use 100LL.  No MoGas as MoGas is not available at airports in my area nor in the areas where I usually fly.  So to keep things simple, I only use 100LL.  This has been with the recommended Mobil 1 Motorcycle Oil.  But it's not supposed to be used with 100LL, so I'm switching to AeroShell Sport next month when I do the annual.  We'll see if that changes anything.



Blue skies & tailwinds,

Bob Borger

Europa XS Tri, Rotax 914, Airmaster C/S Prop.

Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP

3705 Lynchburg Dr.

Corinth, TX  76208-5331

Cel: 817-992-1117

rlborger(at)mac.com



On Jan 18, 2013, at 4:04 PM, Alan Carter <alancarteresq(at)onetel.net> wrote:






Hello Roger,Peter,and All.

I turn the key on my car and it starts, turn the key on a Cessna 150 and it starts,  i use to flip the switch on 4 jet engines and they started.

I keep being told how good the Rotax engine is but it always seems to have problems.!!!

This dreaded Detonation and kicking back seems to cause havoc on Rotax engines,Sprag clutches, Soft Starts, Oversized Starters,Fuels,ete.

Is cold weather i have a fully charged battery plus hook up to my motor cycle battery as well, i am using Mogas super think it about 91,yet i get this dreaded kicking back, i have seen the propeller oscillate it knocks hell out of the engine. My point is this should not be happening why was it not sorted out by Rotax long ago.

I guess a high spin rate and power enough to give engine no choice in the direction its going to turn.

We have Super plus in the UK think its about 94 or 96,Octane, and think also has NO ethanol. However the CAA have dreamed up something about vapour locking, probable some bod has read about vapour locking but i bet there's never been any actual tests carried out.

Its about -5 at the moment bloody cold. Vapour more like freezing of the fuel, really have no idea of the temp which fuel freezes all i know i won,t be up there. 

How would you set about starting a 914 to lessen the chance of kick back.

Regards 

Alan

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Fri Jan 18, 2013 5:07 pm Post subject: Re: Alternate Fuel for 914

Kick back usually comes from a low friction torque with the slipper clutch. have the gearbox re-shimmed will usually take care of it. Using a heavy prop will add to that little issue. the lighter composite props usually kick back a lot less. Poor carb balance and or throttle set point at start will add to kick backs to. Typically a low battery doesn't cause a problem because it can't turn the prop fast enough or hard enough. the old black colored starter will also add to this. If you have the old style starter get the newer gold colored high torque starter. There is a difference.



The Rotax is a good engine when setup properly and maintained properly.

Hi Pete,



You are right about the compression ratio:

912UL 9.0:1

912ULS 11:1

914 9.0:1



The Rotax 914 Operators manual requires this engine to have 91 Oct. or above due to pressures, temps and so on. It can detonate under the right conditions quite easily with an 87 oct. It's too expensive and engine to role the dice and pray nothing will happen since most of us have 91 oct. or higher available.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

AmphibFlyer

Joined: 29 Dec 2009
Posts: 25

Posted: Sat Jan 19, 2013 7:08 am Post subject: Re: Alternate Fuel for 914

 	  davidjoyce(at)doctors.org wrote: 	
		  I have flown my 914 powered Europa all round Europe (around 30 countries) using Mogas. In Austria & Germany where Rotax engines are especially common something like half of all airfields have Mogas on sale. Always use the lower grade version rather than the super grade. Regards, David Joyce

	




DAVID, I'm especially interested in your 914 Europa experience--but would like to be sure that we're using "MOGAS" in the same way. I should have said "regular-grade automobile gasoline," which in the US is 87 octane. Permium gasoline is generally 92 or 93 octane here. Rotax specifies 91 or higher for the 914 and 912S. The 80 hp 912 can run on regular.



So if you've been able to operate your Europa's 914 with the European equivalent of US regular--well, that's really interesting news!

 . 

 . 

ROGER, there are many airfields where jet fuel is the only available aviation fuel, and the only gasoline in the vicinity is regular grade--87 octane if you're lucky. It's to some of those places that I want to fly. Many arctic fields are like that and, I understand, most fields in China, Russia, and many other countries. So you see why I asked.

davidjoyce(at)doctors.org
Guest

Posted: Sat Jan 19, 2013 9:40 am Post subject: Alternate Fuel for 914

Roger, We clearly have problems of translation here. I am 

no expert on fuel so have taken to Google. It appears that 

standard unleaded has a RON of 95 in the UK and Super 

unleaded has a RON of 98, with most of Europe being very 

similar. However it appears that in the States the 

standard product has a RON of between 91 and 93, so 

 anything I said may well be nonsense in a US context! 

Sorry about that. David

On Sat, 19 Jan 2013 07:08:40 -0800

  "AmphibFlyer" <SeaRey(at)AbstractConcreteWorks.com> wrote:

 	  Quote: 	

<SeaRey(at)AbstractConcreteWorks.com>

 davidjoyce(at)doctors.org wrote:

> I have flown my 914 powered Europa all round Europe 

>(around 30 countries) using Mogas. In Austria & Germany 

>where Rotax engines are especially common something like 

>half of all airfields have Mogas on sale. Always use the 

>lower grade version rather than the super grade. Regards, 

>David Joyce

> 

 David, I'm especially interested in your 914 Europa 

experience--but would like to be sure that we're using 

"MOGAS" in the same way. I should have said 

"regular-grade automobile gasoline," which in the US is 

87 octane. Permium gasoline is generally 92 or 93 octane 

here. Rotax specifies 91 or higher for the 914 and 912S. 

The 80 hp 912 can run on regular.

 So if you've been able to operate your Europa's 914 with 

the European equivalent of US regular--well, that's 

really interesting news!

 Roger, there are many airfields where jet fuel is the 

only available aviation fuel, and the only gasoline in 

the vicinity is regular grade--87 octane if you're lucky. 

It's to some of those places that I want to fly. Many 

arctic fields are like that and, I understand, most 

fields in China, Russia, and many other countries. So you 

see why I asked.

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=392632#392632

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brian.davies(at)clara.co.
Guest

Posted: Sat Jan 19, 2013 10:34 am Post subject: Alternate Fuel for 914

We need to be careful with terminology here because the term "octane rating"

means different things in different countries.  In the USA octane rating is

normally quoted as the average between RON and MON =AKI. In Europe octane

rating is normally quoted in RON.  Rotax use RON.



87 octane (AKI) in the USA is roughly equivalent to 91 (RON)octane in

Europe.



So, when Rotax specifies RON 95 for the 914, it is 91 (AKI)octane in the

USA.



How confusing is that!



Regards



Brian Davies



--

Dick Maddux

Joined: 24 Jun 2008
Posts: 516
Location: Milton, Fl

Posted: Sun Jan 20, 2013 5:47 am Post subject: Alternate Fuel for 914

Alan,

  I must say that you have a pretty good handle on the Rotax engine !  When they run,they run good but they sure take a lot of attention ! I have  worked on my engine more than any Cont/Lyc I have owned and I have owned a lot !  (14 planes)

  Good luck to you !

                                 Dick Maddux

                                 912 UL

  

 PS; but I still like it

 [quote][b]

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