All in all it’s 114kg for an engine which when cared for properly and operated within factory limits would outlive our kids.
That depends on how much it’s flown of course but to make your point my O-320-E2C was not flown very much for much of its life and is running well 52 years since it was assembled (it’s not been apart yet).
It cost $35K thirteen years ago with nice plane attached to it as a bonus. I flew it for an hour on Saturday.
What is sure is that Lyco/Conti should have moved all engine to – at least – injection and electronic ignition to get the best of them with any fuel, without the administrative hassle and astronomic prices of change. We all know that Mogas/SP95 has limitation, but for most planes flying low, it is the solution to go for the futur of GA (already the case of UL).
It would have make them on the same consumption levels – or not too far. now lyco and conti are left behind and have just the good old time lovers to praise for them (that one was free :P) . For sure it will not be as reliable as an o360, but look at Thielert/Conti, they are now very reliable this includes the turbo.
This race to reliability will not last for long. and we could say the same for the next step (i e 3000hr OV time).
RV14 wrote:
it’s 114kg for an engine
It certainly is not 
The typical estimate (based on statistics and experience from kit manufacturers) is that a Rotax 912 ULS (standard Rotax), a Jabiru 3300 (6 cylinder version) and the UL350, they all comes in at the same weight. Jabiru and ULPower with 20-30% more power. Considerably lighter is the 80 hp Jabiru 2200 (it replaces Rotax 2 strokes). If you want something more traditional, Continental/Lycoming, the added weight is 100 lbs (50 kg), and that is a O-200 at 100 hp. An O-320/360 is not 100 lbs heavier than a O-200 in general, but certainly could be. It is at least 75 kg heavier than the first 3. That’s an entire person, or 100 l of fuel.
I don’t think weight is one of the upsides of a 320 But the Rotax 915 and 916 are not super light either, due to all the stuff they require in an installation.
I have lots and lots of hours behind an “Edge engine”. Towing gliders with a big bore, fuel injected Rotax 912 (120 hp). Those turbo versions of 170+ hp, how wise is that for anything else but competing in STOL events and similar? As a means of getting rid of the troublesome Bings, then EP’s EFI is really worth considering. EP engines runs much smoother than original Rotax iS’es for some reason, and service is close by. It doesn’t seem to me than even Rotax themselves understand the iS’s (one or two engineers at Rotax obviosly do I would think, but that isn’t of much help for the general users). To my understanding, no one has yet “cracked” the ECU, and that is not a good thing IMO, for several reasons. Why get in iS when we have Edge?
It seems to me that the 915/916 is a corporate decision to extract more money out of the 912, without actually doing any changes to the core engine.
LeSving wrote:
it’s 114kg for an engine
It certainly is not
You mean Textron Lycoming is lying to the FAA
?
Now that I come to think about it, If someone would be happy with just 30Amps of electric power, this 114kg could be further reduced by maybe 2 kg by installing a modern alternator. In era of LED lights and gps navigation why would anybody need more than 30 Amps anyway.
greg_mp wrote:
What is sure is that Lyco/Conti should have moved all engine to – at least – injection and electronic ignition
Electronic ignition, yes by all means, but I wouldn’t be so sure about benefits of electronic fuel injection (EFI) in case of Lycoming. Carburettor is dead simple and very reliable, fuel&air mixture distribution balanced enough to allow for LOP operation. I’m just not sure if benefits of EFI would outweigh cost and complexity.
greg_mp wrote:
to get the best of them with any fuel, without the administrative hassle and astronomic prices of change. We all know that Mogas/SP95 has limitation, but for most planes flying low, it is the solution to go for the futur of GA (already the case of UL).
we need to distinguish between
a) fuel that the O320 would safely and reliably run on and
b) fuel the O320 was certified to use.
In case of a) the O320 would run happily on the cheapest SP95 one can find. Of course, basic engine hygiene is necessary ie. watching the CHTs, oil temp and RPM to be within reasonable limits (what Mike Bush preaches), setting ignition advance properly etc.
b) in terms of required detonation margin, I’m afraid things would stay where they are unless the FAA would change certification rules
PS. Didn’t Pipistrel Pantera use IO390 in its first incarnation? Didn’t they change to a 6 banger because Lycoming told them that they would not “certify” the IO390 for Mogas?
Dry weight discussions about any engine are moot considering the cooling requirements for all of them, either by fuel, water, air, or a combination of. So the only valid weight comparison is the engine package, as installed in subject airplane.
RV14 wrote:
not sure if benefits of EFI would outweigh cost and complexity
Won’t be for me either. I’m looking at replacing my aging engine, and since it is a homebuilt, I had a serious look at converting to full EI + EFI. The brand of choice would be SDS, a company I already had very good experience with, as they sure know what they’re talking about and their products excel. There is no doubt that individual nozzle metering, combined with precise and strong spark delivery provides the best efficiency for any engine.
But my engine is carbed, has dual EI, and the new one will stay this way for the grounds cited above. 40° LOP ops is standard for me, any more and the loss of power becomes excessive.
in terms of required detonation margin, I’m afraid things would stay where they are unless the FAA would change certification rules
My 150 HP O-320 was certified on 80/87 and ran for many years on auto fuel, installed on a certified plane with appropriate STC. It is only the 160 HP version that is subject to that constraint.
my engine is carbed, has dual EI, and the new one will stay this way for the grounds cited above.
I do love the simplicity of my carbed engine. I wonder if those who would replace an engine like that with a turbo’d, geared, liquid cooled, injected engine have ever looked at what that means in terms of complexity and the responsibilities of long term ownership, with their own eyes. There is no way I’d give up the simplicity and serviceability for 50 lbs additional useful load, or 5.5 versus 4.5 hours fuel capacity, or however you want to look at it. The TCDS says mine is 248 lbs or 112 Kg, but I don’t have to put glycol in it or fuss with gearboxes or ECUs. I’ve never even turned a screw on the carb, it just works, and when I do it will be a very simple thing to make it ready for another 2000 hours.
I’ve never particularly liked anything Rotax has designed – the four stokes are all similar with lots and lots of fiddly little parts. A possible exception might be their early two strokes for both planes and motorcycles – which were pretty good designs in e.g. mid-70s Can-Am motorcycles. Otherwise the UL Power concept is closer to a design I would buy if I were building a suitable homebuilt, although it is not confidence inspiring in terms of the company approach that you have to derate the engine for a real world application and 2700 RPM propeller speed. However, six cylinders would be a reasonable compromise in simplicity at 150 HP level or above to get a really smooth engine.
Really the one thing I’d like to change on my carb O-320 is the ignition, if the replacement was self powered. Mags are nice in that they are individually replaceable and not connected electrically to the plane, but the lack of lubrication on a mechanical device is what lets them down in terms of TBO.
Silvaire wrote:
although it is not confidence inspiring in terms of the company approach that you have to derate the engine for a real world application and 2700 RPM propeller speed
You don’t have to. It’s mostly about propellers. I have a wooden prop from Prince. It can turn 3500 rpm, no problems (according to Lonnie Prince ) The prop is 53 inch diameter, and turning 3300 max (speed limiter of the engine). In more “understandable” units this means:
Rotational speed: 3300 rpm → 345.6 rad/s
Radius : 53 inch diameter → 0.5731 m
Tip speed : 345.6 * 0.573 = 198 m/s = MACH 0.577 (considering I can get full rpm at zero velocity, which is very far from the case)
Even at Vne (about 188 knots TAS → 96.5 m/s), this will only be MACH 0.64. Clearly tip speed is of no concern regarding anything at any airspeed. A C-182 with a 82 inch prop at 2700 rpm will have a tip speed of MACH 0.89, which probably will cause M > 1 somewhere at the tip even at static condition.
For most aircraft in the sub 200 hp range, tip speed isn’t really a concern even at 3000+ rpm. Going past 200 hp is another matter entirely. A prop that can handle the RPM could of course be a concern, but not for wooden fixed pitch. But, low prop speed is one of the benefits of a Rotax, enabling very silenced aircraft and simple/light prob hubs for variable pitch props.
2700 RPM is a good speed for 180 HP, much more and the propeller design doesn’t work all that well. One of my cohorts founded and runs Whirlwind, including designing and building these and these and its been discussed. Notice that the composite ground adjustable props for UL Power engines up to 130 HP are all substantially larger in diameter than 53 inches for efficiency, but thereby more highly stressed. They are run at up to 3000 rpm continuous, 3300 rpm for 5 minutes to limit the total exposure. That was found to be the best design compromise to support the UL Power engines at 130 HP power level.
RV14 wrote:
Electronic ignition, yes by all means, but I wouldn’t be so sure about benefits of electronic fuel injection (EFI) in case of Lycoming. Carburettor is dead simple and very reliable, fuel&air mixture distribution balanced enough to allow for LOP operation. I’m just not sure if benefits of EFI would outweigh cost and complexity.
Modern electronic injection ensure that all that is injected get into the cylinder at the moment it is injected, and direct injection is one step fartherr, whereas carbureted cylinder do vacuum an air-petrol mixture from an oscillating airflow, where there are big and small droplet of it, some of them going on the wall. Bigger droplets incorrectly burnt… Of course this system from the 40’s is very robust, but electronic injection is known since more than 50 years and if engine maker efforts were put on it, we would have now good and reliable systems with backups.
It’s the cas on airbus and boeing actually, their jet engines have fadecs with redundancy and have specific generators in addition to main one (per engine).
You can always make the things better.
Actually Edge performance (rotax tuner and provider) do make a ket with additional generator for its injection kit, that can be a small 15a or a big one, and provide 2 pumps. Much better than the DA40 CD135 engine that has only 1 HP pump and 1 common rail – and it is known to be safe.
Really the one thing I’d like to change on my carb O-320 is the ignition, if the replacement was self powered. Mags are nice in that they are individually replaceable and not connected electrically to the plane, but the lack of lubrication on a mechanical device is what lets them down in terms of TBO.
The slow progress of electronic ignition is a curious thing.
I think a lot of it is market acceptance in the US. Magnetos are a known quantity, and there is no obvious reason why – in cruise – the MPG should be significantly different. We’ve done this topic before e.g. here and AFAIK nobody has delivered data disproving this.
And there has been so much junk engineering in GA (and continues to be) that potential customers remain wary.
