---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Fri 01/18/13: 9 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:50 AM - Re: Alternate Fuel for 914 (David Joyce) 2. 06:11 AM - Re: Alternate Fuel for 914 (Roger Lee) 3. 08:38 AM - Re: Re: Alternate Fuel for 914 (Peter Jeffers) 4. 08:58 AM - Re: Re: Alternate Fuel for 914 (Robert Borger) 5. 02:05 PM - Re: Alternate Fuel for 914 (Alan Carter) 6. 02:39 PM - Re: Re: Alternate Fuel for 914 (David Joyce) 7. 02:44 PM - Re: Re: Alternate Fuel for 914 (Robert Borger) 8. 02:52 PM - Re: Re: Alternate Fuel for 914 (Robert Borger) 9. 05:07 PM - Re: Alternate Fuel for 914 (Roger Lee) ________________________________ Message 1 _____________________________________ Time: 12:50:04 AM PST US From: "David Joyce" Subject: Re: RotaxEngines-List: 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" wrote: > > > 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.) > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=392547#392547 > > > > > > > >Un/Subscription, >http://www.matronics.com/Navigator?RotaxEngines-List >Forums! >Admin. > > > ________________________________ Message 2 _____________________________________ Time: 06:11:03 AM PST US Subject: RotaxEngines-List: Re: Alternate Fuel for 914 From: "Roger Lee" 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. Light Sport Repairman - Maintenance Rated Rotax Repair Center - Heavy Maint. Rated Home 520-574-1080 TRY HOME FIRST Cell 520-349-7056 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=392567#392567 ________________________________ Message 3 _____________________________________ Time: 08:38:51 AM PST US From: "Peter Jeffers" Subject: RE: RotaxEngines-List: Re: 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 PostPosted: Fri Jan 18, 2013 6:09 am Post subject: Re: Alternate Fuel for 914 Reply with quote _____ 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. -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Roger Lee Sent: 18 January 2013 04:04 Subject: RotaxEngines-List: 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. Light Sport Repairman - Maintenance Rated Rotax Repair Center - Heavy Maint. Rated Home 520-574-1080 TRY HOME FIRST Cell 520-349-7056 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=392558#392558 ________________________________ Message 4 _____________________________________ Time: 08:58:11 AM PST US Subject: Re: RotaxEngines-List: Re: Alternate Fuel for 914 From: Robert Borger 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@mac.com On Jan 18, 2013, at 10:38 AM, Peter Jeffers wrote: 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 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. -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Roger Lee Sent: 18 January 2013 04:04 Subject: RotaxEngines-List: 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. Light Sport Repairman - Maintenance Rated Rotax Repair Center - Heavy Maint. Rated Home 520-574-1080 TRY HOME FIRST Cell 520-349-7056 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=392558#392558 ________________________________ Message 5 _____________________________________ Time: 02:05:32 PM PST US Subject: RotaxEngines-List: Re: Alternate Fuel for 914 From: "Alan Carter" 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 ________________________________ Message 6 _____________________________________ Time: 02:39:25 PM PST US From: "David Joyce" Subject: Re: RotaxEngines-List: Re: 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" 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 > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=392604#392604 > > > > > > > >Un/Subscription, >http://www.matronics.com/Navigator?RotaxEngines-List >Forums! >Admin. > > > ________________________________ Message 7 _____________________________________ Time: 02:44:31 PM PST US Subject: Re: RotaxEngines-List: Re: Alternate Fuel for 914 From: Robert Borger 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 -2C in a north Texas winter. Any colder than that (it can get to -20C 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@mac.com On Jan 18, 2013, at 4:04 PM, Alan Carter 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 ________________________________ Message 8 _____________________________________ Time: 02:52:31 PM PST US Subject: Re: RotaxEngines-List: Re: Alternate Fuel for 914 From: Robert Borger 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@mac.com On Jan 18, 2013, at 4:44 PM, Robert Borger 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 -2C in a north Texas winter. Any colder than that (it can get to -20C 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@mac.com On Jan 18, 2013, at 4:04 PM, Alan Carter 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 ________________________________ Message 9 _____________________________________ Time: 05:07:38 PM PST US Subject: RotaxEngines-List: Re: Alternate Fuel for 914 From: "Roger Lee" 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. -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Repair Center - Heavy Maint. 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