I turned the Hobbs meter over on my Rans S-7S 912S powered bird to 2001.9 hrs the other day on a flight back from Montana, totally trouble free with not even a minor hiccup. It will continue to be flown as is, with only some minor hose replacements as I feel like I ought to do something to it. I have never had such a long run, 9 years since I built it, of glitch free flying, it just starts and runs perfect, every time. I was a reluctant convert to the Rotax, in fact I used a converted Subaru on my first S-7 (1300 good hrs, but heavy and draggy as the cowl was like a J-3's, with most of the engine hanging out in the slipstream), but after getting behind one, I am a believer. No oil on the hangar floor either! It uses less then 1 quart every 50 hours! Over the last few years, I have noticed a cessation somewhat of dissing remarks about "that snowmobile engine" by Lycoming and Continental pilots, it seems to have earned a grudging acceptance. Me, I'm totally sold on it

That's awesome, nice to here of somebody having such success with one of these infernal contraptions, regardless of brand.

Now if they would just make engines in the 200 and 300hp ranges...

[quote="Halestorm" Now if they would just make engines in the 200 and 300hp ranges...[/quote]

Actually, they did, well it was Bombardier-Rotax that developed it. Not really sure what become of it though. It was in a Murphy Super Rebel or Moose at Oshkosh several years ago. Last I had read was they wanted to focus on recreational engines and scratched the project.

Thanks for the update. What percentage of hours would you guess you were burning E10?

About 1200 hours on mine in 5 years and couldn't be happier. Expect to go well beyond TBO

Not only TBO.. but also on hopped up higher performance cylinder/piston combos! And running below Rotax's "recommended" minimum RPM under full power with that large prop you have!

Now run it another 2000hrs! Did you do any gear box inspections along the way? not sure if the non-compensated / non-friction clutch UL box needs the same attention as the ULS?

They really are incredible engines. Light, powerful, fuel efficient. Mine is tad oily under the bottom of the case, but it never actually drips on the floor/inside cowl...ever. Uses just a little oil with the zipper cylinders/pistons. Uses just a little water (have to add a little every couple months. Almost 700hrs now... Hopefully lots of years and hours to go as I can't afford to replace it anytime soon!!

Great report though!.. I've read of quite a few in the 3-4000hr range by those brave enough to keep it spinning! And really, I'm having trouble coming up with a reason why not too! Especially if taken care of.

That's, awesome, others at my airport have also passed TBO with you same results. When I had to justify my Rotax choice years ago I explained it was partly based what who was flying every morning and who had their cowling off. No regrets.

Rotax has a new engine being released in 2017, the Rotax 915iS. 4 stroke, 4 cylinder turbocharged, redundant electronic fuel injection, 135 hp. Full take off power to 15,000 ft, service ceiling of 23,000 ft.

It would be interesting to see how the 135 hp up 15,000 ft compares to some of the large GA engines at the same altitudes.

Sounds like you are flying it a lot which is the 'secret' to longevity.

I think that the Rotax advantages to longevity are (partial) water cooling and burning Mogas.

Mountain Doctor wrote:Sounds like you are flying it a lot which is the 'secret' to longevity.

I think that the Rotax advantages to longevity are (partial) water cooling and burning Mogas.

agreed, and also short stroke (less piston side load)

GravityKnight wrote:

Mountain Doctor wrote:Sounds like you are flying it a lot which is the 'secret' to longevity.

I think that the Rotax advantages to longevity are (partial) water cooling and burning Mogas.

agreed, and also short stroke (less piston side load)

Indeed, I think that short stroke is often overlooked, just the high RPM gets noticed, so the uninformed think they "won't last." For whatever reason, flying a lot, and often, seems to help. One other thing, mine has NEVER used any coolant, zilch, nada. That amazes me.

courierguy wrote:

GravityKnight wrote:

Mountain Doctor wrote:Sounds like you are flying it a lot which is the 'secret' to longevity.

I think that the Rotax advantages to longevity are (partial) water cooling and burning Mogas.

agreed, and also short stroke (less piston side load)

Indeed, I think that short stroke is often overlooked, just the high RPM gets noticed, so the uninformed think they "won't last." For whatever reason, flying a lot, and often, seems to help. One other thing, mine has NEVER used any coolant, zilch, nada. That amazes me.

That is amazing! mine weeps a little out of the water pump weep hole. Just stays wet down there (doesn't drip) .. so after a few months I have to add a cup or twos worth.

GravityKnight wrote:That is amazing! mine weeps a little out of the water pump weep hole. Just stays wet down there (doesn't drip) .. so after a few months I have to add a cup or twos worth.

That could be a simple water pump seal or the shaft to the water pump that goes through the seal, if these engines are anything like other small engines I've worked on in the past. Should be a simple fix.

But great to hear about their reliability. Has it justified the costs of the engines over the other manufacturers for y'all?

UngaWunga wrote:

GravityKnight wrote:That is amazing! mine weeps a little out of the water pump weep hole. Just stays wet down there (doesn't drip) .. so after a few months I have to add a cup or twos worth.

That could be a simple water pump seal or the shaft to the water pump that goes through the seal, if these engines are anything like other small engines I've worked on in the past. Should be a simple fix.

But great to hear about their reliability. Has it justified the costs of the engines over the other manufacturers for y'all?

It's a ceramic seal and they are designed to weep actually.. there is a rotax specification on how much is normal to weep and lose (I haven't measured mine officially in order to compare it with their spec though...) The pumps are generally very reliable... mine might weep more than normal, but I doubt it as it doesn't actually form enough to drip. But my overflow tank isn't real large and needs to be refilled a couple times a year (I put like ~ 130-140hrs on it last year)

Seems the rotax price wise is actually really good and competitive (when compared to other actual aviation engines, not car conversions etc. which is fair since it is obviously an aviation engine through and through - some don't like to admit that, but it is). I don't recall prices of Jabirus, UL powers etc. off hand but iirc the rotax was often cheaper (some of the others had a wider range of power offerings though)

Well, kinda [emoji39] We can't overlook the bigbore installation done at 1300hrs. So the bottom end has gone the full 2000 but you topped it, by choice, at 1300.

While I'd really miss the sound of a small continental you can look past the reliability of these great little engines. I think the key difference is the water cooled heads.

Congrats CG, hope you get another 2000hrs out of it.