# Rotax 916

EGTs are the limiting factor. I'll give it 100% throttle until 600-800' agl then wind it back to whatever % keeps EGT below 1700.

POH says 5 min max but without a range it doesn’t compute for me. So realistically what we’re talking about here is you can run max rpm for five minutes or until exhaust gas temperature is reach max allowable. Then you have to let the engine return to normal operating temperatures. So theoretically, if there was some reason for it, you could run full power for five minutes then cruise for 30 minutes and then full power for five minutes then cruise for 30 minutes, etc. etc. As long as your EGT’s return to normal temperature, right?

POH says 5 min max but without a range it doesn’t compute for me. So realistically what we’re talking about here is you can run max rpm for five minutes or until exhaust gas temperature is reach max allowable. Then you have to let the engine return to normal operating temperatures. So theoretically, if there was some reason for it, you could run full power for five minutes then cruise for 30 minutes and then full power for five minutes then cruise for 30 minutes, etc. etc. As long as your EGT’s return to normal temperature, right?

Do you ever get up to 10-13k? What does it true out at that max continuous RPM? Seems like 140 knots is doable in several of these LSAs.

POH says 5 min max but without a range it doesn’t compute for me. So realistically what we’re talking about here is you can run max rpm for five minutes or until exhaust gas temperature is reach max allowable. Then you have to let the engine return to normal operating temperatures. So theoretically, if there was some reason for it, you could run full power for five minutes then cruise for 30 minutes and then full power for five minutes then cruise for 30 minutes, etc. etc. As long as your EGT’s return to normal temperature, right?
Consider it 'takeoff power.' You're managing engine temps just like a traditional aircraft engine.

In a Superstol with CS prop, that's 9.5+ gph and 1200-2000 fpm. Full throttle Vy climb deck angle limits forward visibility, so the available power isn't necessary during my normal operations.

The 10mph TAS difference from 5.5-6.0gph economy cruise and ~8.2gph max continuous power doesn't justify the extra fuel burn.

Consider it 'takeoff power.' You're managing engine temps just like a traditional aircraft engine.

In a Superstol with CS prop, that's 9.5+ gph and 1200-2000 fpm. Full throttle Vy climb deck angle limits forward visibility, so the available power isn't necessary during my normal operations.

The 10mph TAS difference from 5.5-6.0gph economy cruise and ~8.2gph max continuous power doesn't justify the extra fuel burn.

Very cool. Thanks for the education! Sounds like setting up with a cruise prop is ideal for XC flyer and there is still plenty of FPM climb out.

Very cool. Thanks for the education! Sounds like setting up with a cruise prop is ideal for XC flyer and there is still plenty of FPM climb out.
The MT 80 constant speed was recommended and its been great. Seems to make the most of the 915 and in a STOL plane every bit of cruise speed is appreciated.
Since I have A/P its a TAA for logbook purposes.

GA industry seems like Bring-a-Trailer type of market …. also eerily similar to your typical automobile market in Cuba or what used to be reality in various eastern block countries where the only thing you could get were 50-60 year old car models - not exactly what I would consider a healthy and robust market

The difference is that market forces, not authoritarian government, have created the current situation. And its a good thing that contrary to your earlier point includes demand from a segment of car people who want sustainable simplicity and choose to spend a lot of money on it instead of buying new limited-life cars with their fun money. In the case of GA almost everybody wants sustainable simplicity and for good reason, not least because while you can't manufacture an airplane cheaply, there are lots of planes and engines out there which are and will be good investments, thriving and surviving decades after they were built.

While a lot of people were whining and missing the point even pre-2020, I think the best opportunity ever to buy, own and fly light aircraft may now have passed them by as attrition and increased demand has ratcheted the costs upward. Even without COVID politics bumping up demand, no evolved and affordable situation lasts forever and privately owned GA may get to point where something like the Rotax 916 might be able to occupy a small niche in the US market, even at its very high cost level. Maybe clone Lycomings will take over more broadly, as happened with PMA engine parts. For sure the GA market will continue to evolve, but driven by demand not fantasy.

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The MT 80 constant speed was recommended and its been great.

Is it correct that due to engine/gearbox/prop vibration issues the engine cannot use an aluminum prop, only wood core and some composite props?

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Is it correct that due to engine/gearbox/prop vibration issues the engine cannot use an aluminum prop, only wood core and some composite props?

Whatever 'low inertia' means to Rotax, I guess. I wouldn't hang the extra weight of an aluminum cs setup on the nose even if it were available.

The options for the 915 were fixed, ground adjustable, and CS. For my use and resale considerations, CS was the obvious choice.

Am I missing something? Can Rotax be run at full horsepower continuously, despite what the manufacturer says? I read that the 916 is capable of 160 hp during takeoff, but only has 137 continuous hp, which is hardly better than the 135 continuous hp of the 915. Can the 915 run at 141 hp full time, and will the 916 be able to run at 160 hp all the time?

Am I missing something? Can Rotax be run at full horsepower continuously, despite what the manufacturer says? I read that the 916 is capable of 160 hp during takeoff, but only has 137 continuous hp, which is hardly better than the 135 continuous hp of the 915. Can the 915 run at 141 hp full time, and will the 916 be able to run at 160 hp all the time?

Nobody’s going to stop you.

Nobody’s going to stop you.
Yes - but will the engine stop you by breaking?

Yes - but will the engine stop you by breaking?
See my prior post. They both show 5 min max. The other poster FancyG explained the temp component. Over temp seems like a clearly bad idea at any altitude

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Awesome news. Lycoming is getting way to expensive nowadays . Gives more options

See my prior post. They both show 5 min max. The other poster FancyG explained the temp component. Over temp seems like a clearly bad idea at any altitude
Yes. My point was that no ONE will stop you. But the ENGINE will. So much for my attempt at humor.

Wrong. It has 160 hp during takeoff, but the continuous horsepower is only 137, a grand whopping total of two extra hp than the 915.
So at 2,500 feet the rotax and a 150 hp O-320 are tied.
Two minutes worth of climb at 600 feet a minute gets you half way there. If it’s 5 minutes at 160 then 4 minutes worth of climb gets you to about 2500 feet just in time to reduce power down to what the O-320 is making. Assuming a STP day at sea level. On a hot day it shifts in the favor of the Rotax.

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The MT 80 constant speed was recommended and its been great. Seems to make the most of the 915 and in a STOL plane every bit of cruise speed is appreciated.
Since I have A/P its a TAA for logbook purposes.
I can’t find an MT-80 on their website. I did find something that said the MT-34 can be used with a 915.

At the Sling presentation Monday, they said the 916 would be their default engine config for Sling HighWing, going forward.

At the Sling presentation Monday, they said the 916 would be their default engine config for Sling HighWing, going forward.
That should climb like a beast. 2025 is going be amazing for new planes. Lycoming and Conti better get it together or Rotax is it.

At the Sling presentation Monday, they said the 916 would be their default engine config for Sling HighWing, going forward.

I do love the High Wing. I just wish it was a continuous power bump.

I do love the High Wing. I just wish it was a continuous power bump.
Wait till Rotax 917 or whatever will be their next version …

Wait till Rotax 917 or whatever will be their next version …
Yep. 180 max then 160 at cruise. Seems like a winner.

Awesome news. Lycoming is getting way to expensive nowadays . Gives more options
I am going to assume you have not priced a 916. 49,000 is the current price and if the war in the Ukraine keeps going it will probably be 60k in two years.

cdb
I am going to assume you have not priced a 916. 49,000 is the current price and if the war in the Ukraine keeps going it will probably be 60k in two years.
War in Ukraine ? Are there any engine components manufactured over there ?

I had the same reaction. Rotax is from Austria. If their operation is affected by Ukraine then Europe is in trouble. I think pricing for Rotax will keep beating traditional by miles.

I'm still a huge fan of Rotax and alternative engines in general, but I don't know that I would say \$49,000 is beating traditional by miles.

I had the same reaction. Rotax is from Austria. If their operation is affected by Ukraine then Europe is in trouble. I think pricing for Rotax will keep beating traditional by miles.
Everything is affected by Ukraine because of the United States. Inflation here affects prices everywhere, and continuing to write IOUs on our children is a guaranteed way to continue the inflation.

Everything is affected by Ukraine because of the United States. Inflation here affects prices everywhere, and continuing to write IOUs on our children is a guaranteed way to continue the inflation.
Undoubtedly a conversation for a different forum but I don’t disagree with that assessment.

I'm still a huge fan of Rotax and alternative engines in general, but I don't know that I would say \$49,000 is beating traditional by miles.
Well, the costs of new or rebuilt Lycoming/Conti have gone up a lot. There are all the obvious HP and architecture differences we could talk about. If I had the opportunity to build a plane tomorrow it would have a Rotax for the simple fact that it’s new tech. FADEC and modern engines should be the way forward. Lycoming and Conti haven’t innovated in so long I doubt they know how anymore. I guess it depends on what you consider as the deciding factors for a “win”. But to me, value in the Rotax platform is higher than in old school air cooled Dino engines. To each their own of course…

Oh I absolutely agree with you. If my dad and I are able to get this Experimental project going it's going to have an EFI Lycoming to get the best of both worlds. If Rotax had a higher output engine I'd absolutely consider one.

Oh I absolutely agree with you. If my dad and I are able to get this Experimental project going it's going to have an EFI Lycoming to get the best of both worlds. If Rotax had a higher output engine I'd absolutely consider one.
They have a 180 HP at edge now

It's a great setup, but looks like they're still testing it. Also, it's not continuous, which is the part that gets me. If they had a 2,000hr TBO engine with 180hp, I'm in. But, since we haven't even started, it's kind of a moot point anyway since it very well may reach that by the time we're ready for an engine

It's a great setup, but looks like they're still testing it. Also, it's not continuous, which is the part that gets me. If they had a 2,000hr TBO engine with 180hp, I'm in. But, since we haven't even started, it's kind of a moot point anyway since it very well may reach that by the time we're ready for an engine
I think it has to be coming. They say it’s tested to 202 HP. Besides, the real “get” is the turbo. Keeping 140 HP continuous past 10k feet means that performance curve goes to the Rotax as the dino engine rolls off from altitude losses. So 180 HP in takeoff when it matters and full continuous power at altitude would make a perfect performance for the missions I want. One thing is for sure. Rotax is improving all the time.

War in Ukraine ? Are there any engine components manufactured over there ?
Rotax engines are the larger drone engine of choice. Demand is very high for the engines and some manufacturers are embargoed. Rotax engine thefts right off aircraft are a real issue in Europe at the moment. Drone demand is driving up costs as demand is soaring. It’s simple supply and demand, drone demand is soaring to replace lost drones and increase drone fleets Worldwide.

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Rotax engines are the larger drone engine of choice. Demand is very high for the engines and some manufacturers are embargoed. Rotax engine thefts right off aircraft are a real issue in Europe at the moment. Drone demand is driving up costs as demand is soaring. It’s simple supply and demand, drone demand is soaring to replace lost drones and increase drone fleets Worldwide.
Ok. That actually makes sense. I forgot that the bulk of the aviation engines Rotax has put in the air were military drones. Another indicator that Rotax is the future of GA light aircraft engines.

Unless you have a constant speed prop.

Unless you have a constant speed prop.
What do you mean? That engine supports MT if memory serves?

I don’t see the market of the future down selecting to an engine that uses a wood constant speed propeller, especially if it’s a liquid cooled geared turbocharged engine with an ECU that doesn’t make enough power to justify the maintenance burden of all that stuff.

Same issue as the diesels in this regard. Lots of complexity, marginal quality, little benefit.

My plane has an MT constant speed prop and while it works, it’s crude. Something like a Whirlwind prop is in another world of quality, and attaching it to a four cylinder Lycoming makes an easy to own package.

One would have to assume that there will be more choices emerging. If not the prop makers are stupid. The MOSAIC changes means opportunity to get constant speeds on a bunch of former LSA type aircraft. My bet is that better props are coming.

What do you mean? That engine supports MT if memory serves?
If you have a constant speed prop a lycoming will develop full rated power for takeoff.