Sport Pilot Talk

I just found a gas station near my airport with NO ethanol 90 octane gas. Is it acceptable in the 912 ULS? Can I mix it in with 100LL? My plane is currently fueled with 100LL after its flight back east from LA. I’d like to start fueling with unleaded, especially after the next oil change.

The other alternative is 93 octane with ethanol.

Thanks...

Here is quite relevant thread on the very subject ...

https://www.rotax-owner.com/en/rotax-fo ... or-912-uls

For the RV-12 SLSA that I have the Manual requires min 91 octane unleaded.
There were a couple of gas stations near me in SC that sold 93 unleaded until the supply ran out. They switched to 90 unleaded and I switched to 93 E10 with no ill effects thus far.

Vans approve 93E10. Actually they operated an RV-12 on each coast, one running exclusively 100LL and the other 93E10 and, following different oil change intervals for each type, found no adverse issues. My mechanic and I have seen no adverse issues using Mogas with ethanol so far. The plugs are very clean and my mechanic changes them each annual at my request. At under $3 per plug its my choice.

Like you, on the flight home from the factory I used 100LL exclusively as this is what is typically a available, but since then it’s been Mogas. Most of my flying is relatively local such that I bring my own fuel to the hangar. If it sits more than a couple of weeks in the cans I pour it into the truck so I can always try and put the freshest fuel in the plane.
For the price of 93E10 in my area, and store discounts, I always use 93E10, and won’t contemplate using/mixing with 90 octane even if it is non-ethanol.
Non ethanol 89/90 is fairly popular in SC but I always use 93.
On long cross countries if only 100LL is available I have no problem mixing it but I don’t do it regularly or to average out the octane.

At the end of the day Mogas is always cheaper than 100LL, and the new Swift type fuels will likely cost more, so I simply put the highest octane Mogas in.

Swift fuel was around $3.80 last time I fueled up at KMGC..
Non ethanol Mogas 91 was $4.20 at my local airport and 100LL is $4.20 as well ... so Mogas/Swift makes more sense for me..

Well that price is good. Our airport manager said when they get the new fuels they’d be similar to 100LL, just sayin.
Either way, I’ll stick to Mogas and will be even happier to mix with the new fuels on longer trips. 93E10 is around $2.75 near me after loyalty discounts.

Bottom line...follow airplane manual for approved fuel type.

Well, you are lucky then...

We can’t use Ethanol Mogas in Stings since about time Rich busted his tank

Maybe because the RV-12 has a metal tank, which I wish was split into wing tanks, but that’s another story.

I remember reading Rich’s gas tank story and my heart went out to him.

Warmi wrote:Here is quite relevant thread on the very subject ...

https://www.rotax-owner.com/en/rotax-fo ... or-912-uls

Thanks Warmi, good info in that thread.

I may just run Sunoco 93 unleaded with ethanol.

Just remember, folks, that ethanol is a solvent. It dissolves things. Like o-rings, rubber hoses, fuel filters, fiberglass resins, and the sealant used in wet wing tanks. Some airframe manufactures (Van's, for example) design around this, approving E10 mogas. Others do not. So tread with caution here. I, for one, will never put ethanol in an aircraft (and wish I didn't have to do so in motorcycles and sports cars).

I'm fortunate enough to have an oil company 10 minutes down the road from my house that sells 93 octane, ethanol free fuel for $3.45 a gallon (on my last purchase). If on longer trips I need to use 100LL so be it. But I'll switch back to MOGAS as soon as I return. I've bought Swift Fuel in Sebring on my last trip down for some parts but I dont remember what I paid for their fuel.

I remember on Rotax training at Leading Edge , the instructor specifically rated fuel preference for Rotax as :

1. Swift ( UL 94)
2. Unleaded Mogas 91+
3. Ethanol Mogas
4. 100 LL

I will take ethanol over inadequate octane every time, if the airframe allows ethanol. The results of detonation are about an $18,500 mistake for a Rotax 912ULS engine.

As a data point, I have run about 90% 93 octane mogas with ethanol for 500 hours and it has been fine. But Flight Design is emphatic that 10% ethanol is fine for the CT series, so YMMV. I refuel with 100LL with Decalin added when I'm traveling away from home and don't lose any sleep over the lead.

MrMorden wrote:I will take ethanol over inadequate octane every time, if the airframe allows ethanol. The results of detonation are about an $18,500 mistake for a Rotax 912ULS engine.

As a data point, I have run about 90% 93 octane mogas with ethanol for 500 hours and it has been fine. But Flight Design is emphatic that 10% ethanol is fine for the CT series, so YMMV. I refuel with 100LL with Decalin added when I'm traveling away from home and don't lose any sleep over the lead.

Concur.
The only reservation I have with ethanol use, is if the aircraft sits idle for long periods of time.

MrMorden wrote:I will take ethanol over inadequate octane every time, if the airframe allows ethanol. The results of detonation are about an $18,500 mistake for a Rotax 912ULS engine.

As a data point, I have run about 90% 93 octane mogas with ethanol for 500 hours and it has been fine. But Flight Design is emphatic that 10% ethanol is fine for the CT series, so YMMV. I refuel with 100LL with Decalin added when I'm traveling away from home and don't lose any sleep over the lead.

Yeah, I won't touch anything below 91 but ... I distinctly remember the owner of the school I trained at running all his planes (Remos) on 93 mogas with ethanol and constantly complaining how much additional maintenance he needs to do ( especially rubber related ) because of the fuel he uses.

Just found another nearby gas station with 91 no ethanol unleaded.