I wish new C-172s were a bit better.

[Old Dog Flying]

That doesn't mean good auto engines are good aircraft engines

Finally, after decades of nonsense, someone admits it.

there must be some room for improvement

Are you proposing that there is some Grand Conspiracy (tm)
stopping people from implementing these improvements?

Sure, blame paperwork for certified aircraft, but what's holding
the homebuilders back?

They all fly Lycomings. Only tweak they've made is to replace one
magneto with electronic ignition, for better starting. Despite all
the decades of hype, no one runs FADEC. And that's it.

To all the auto engine fans out there: Why aren't you running
a Porsche PFM engine? Superior German engineering - or not.
Despite blowing a billion bucks, they couldn't out-perform a
Lycoming, which all the experts claim is "old technology". Well,
maybe it is, but it's also better technology.

How many auto engine conversions are there at your airport?
How many have you personally flown as PIC?

There is a guy a YNJ with a Bearhawk powered by a Rover V8 with belt reduction drive...quiet, powerful and smooth. The 80 year old fellow that designed and built the unit even designed and molded his own isolation shocks. The drive belt, an industrial unit, is good for 10,000 hrs.

A friend, the son of the old fart above, is re-building a C175 as a homebuilt, and it will be powered by a GM V8 with the same drive unit.

SF at Ypk has two 80% scale Spitfires under construction, both V8 GM powered. One of the Spits has flown with a V6 but required rebuilding due to pilot error accident.

I havwn't flown any of these machines but I have flown a couple of Auto engine powered homebuilts and they are a lot smoother than my 0-235 C2C.

Barney

[CpnCrunch]

How many auto engine conversions are there at your airport?
How many have you personally flown as PIC?

There is a guy a YNJ with a Bearhawk powered by a Rover V8 with belt reduction drive...quiet, powerful and smooth. The 80 year old fellow that designed and built the unit even designed and molded his own isolation shocks. The drive belt, an industrial unit, is good for 10,000 hrs.

A friend, the son of the old fart above, is re-building a C175 as a homebuilt, and it will be powered by a GM V8 with the same drive unit.

SF at Ypk has two 80% scale Spitfires under construction, both V8 GM powered. One of the Spits has flown with a V6 but required rebuilding due to pilot error accident.

I havwn't flown any of these machines but I have flown a couple of Auto engine powered homebuilts and they are a lot smoother than my 0-235 C2C.

Barney

And how many engine failures have they had?

[akoch]

A lot of homebuilders use Rotax, which is available in 80, 100 and 120hp versions. The track record by now is proved and the TBO is 2000h. A flew a Rotax plane for 50h PIC. In fact I would gladly own a 100 or 120hp Rotax. For the same horsepower as a O200 or IO240 it is considerably lighter, smoother and yes feels as more modern engine.

A saw a few Jabiru-powered planes, taxied one. Seemed to be a smooth 6-cilinder 120hp powerplant.

I don't see anything more powerful from these two companies, so Lycomings still rule. But may be in due time.

[Shiny Side Up]

there must be some room for improvement

Are you proposing that there is some Grand Conspiracy (tm)
stopping people from implementing these improvements?

Sure, blame paperwork for certified aircraft, but what's holding
the homebuilders back?

Well now that you mention it...

The certification process for new or modified engines for aircraft is nothing short of gargantuan. You must even admit that while the TCMs and Lycomings are good engines, there are still some hold overs on them that could really be improved some. I mean some of the mags systems on engines that are approved are nothing short of archaic, but no one makes new ones simply because overcomming the certification process is way to much money. I mean why must an old C-65 be damned to be stuck with some crappy mags just so the thing can be still a certified aircraft? The point being that the process has really stifled the availability of a variety of viable engines. Crap, why doesn't someone still make gypsy majors? Or at least an updated fuel injected one. Its a good engine right, powered lots of airplanes, still does.

Home builders just use what they can get a hold of, which often turns out to be old aircraft engines. There are few automotive engines sutiable for immediate use, since to turn them into useable airplane engines is a lot more work than just sticking it on the airframe and attaching a prop. I know the fellow who designed the Titan Mustang scale kit and he used modified chevy v6 and v8 engines in those things for thousands of hours without issue - but they also required a lot of modification, the sound with the stub exausts was worth the trouble alone.

Personally though, I'm hoping Honda decides to get into the aero engine game. They keep seeming like they're toying around with the idea. Just outright copy the lycoming, just so there's some competition in the market. Maybe even if they just started making approved parts for said Lycs and TCMs.

[xysn]

Say Eclipse/Katana burn about 17-21 liters per hour going 250km/h. A Civic does 100km/h and burns 7liter/h or so. Pretty much same figure. Consider that an aircraft goes more direct as well.

This is true for comparing driving vs flying but it's not really fair as a comparison of engine technology. The point I'm trying to make is the Rotax drinks 17 litres per hour to make 60 hp, and a Honda R18 engine drinks 7 litres per hour to make 70 hp.

Are you proposing that there is some Grand Conspiracy (tm) stopping people from implementing these improvements?

Of course not. I just don't think there are enough pressures, market or regulatory, to motivate innovation in GA engines. The market for fuel efficient road vehicles is worldwide. There are some 250 million registered passenger vehicles in the US alone vs 223 thousand private aircraft. As others have pointed out the barriers to innovation are also quite high.

The homebuilder angle is interesting but I think the market is too small for the aero-engine manufacturers to create a fuel efficient uncertified engine just for them.

It would be interesting to compare the fuel efficiency gains in commercial aviation, where engine manufacturers have a much greater incentive to improve fuel efficiency, to the gains made in general aviation.

[Old Dog Flying]

Capncrunch: NONE!

[woodzi]

This is true for comparing driving vs flying but it's not really fair as a comparison of engine technology. The point I'm trying to make is the Rotax drinks 17 litres per hour to make 60 hp, and a Honda R18 engine drinks 7 litres per hour to make 70 hp.
[

Actually a car needs around 10-15 HP to maintain 100 km/h. It is impressive that a slippery aircraft like a Katana can achieve a similar similar fuel consumption per km as a small car while travelling at more than twice the speed.

[CpnCrunch]

Capncrunch: NONE!

Well I'm not sure if that is typical. Rotax is specifically designed for aircraft use, and the 4-stroke is very reliable (in fact I'd prefer a new rotax 912 to an ageing lycoming or continental), but in general auto engines have a lot more engine failures from what I hear.

[TeePeeCreeper]

Rotax is specifically designed for aircraft use, and the 4-stroke is very reliable.

Umm... Not exactly the case... I had one in my snowmobile long before Bombardier started putting "paperwork" together to certify them in small airplanes...

When I visited the factory, I asked what's the difference between certified aircraft powerplants and the "other" engines... I was told by a BRB rep (he was grinning) "just a piece of paper... For all intensive purposes they are the same".

[akoch]

By "other" engines they implied the noncertified version of the Rotax'es. These are still aircraft engines, designed as such. But used in the experimental scene.

As for reliability - these by now proved themselves, while the TBO is 2000h most of them routinely does 3000h between overhauls. Even the gearbox turned out to be trouble-free.

[Colonel Sanders]

As for reliability - these by now proved themselves

That's quite a whopper. There are at least 3 dead people that I can
directly attribute around here to failure of the Rotax engines in ultralights,
and plenty of other non-fatal forced landings that resulted in destruction
of the airframe. If you added up the number of accidents nation-wide
it would be staggering, but there is no requirement to report an ultralight
accident, I am told.

They don't even have carb heat, which is insane.

most of them routinely does 3000h between overhauls

Another incredible whopper. There is not a single ultralight in Canada
that would dare to fly 3000 hours between overhaul on one of those
chain saw engines. I try to stay as far away from those contraptions
as I can, but I understand that they are considered worn-out at 500 hours.

As usual, the internet suffers from an incredible Reality Gap (tm).

Hey, I heard Porsche is adapting it's car engine for airplanes! Ought
to be a winner. Everyone knows that German engineering is 'way
better than those old air-cooled engines we currently have now.

[CpnCrunch]

That's quite a whopper. There are at least 3 dead people that I can
directly attribute around here to failure of the Rotax engines in ultralights,
and plenty of other non-fatal forced landings that resulted in destruction
of the airframe. If you added up the number of accidents nation-wide
it would be staggering, but there is no requirement to report an ultralight
accident, I am told.

2-stroke or 4-stroke? The 4-stroke are pretty reliable, but I wouldn't really trust a 2-stroke.

As for carb ice, they seem to be fairly immune to icing, but you can get carb heat kits for the 912.

[Colonel Sanders]

Two stroke. Everyone tells me they don't have to maintain
them because they're not certified.

And they carry passengers in those things?!

[Beefitarian]

I wonder if they might have less issues if they were being maintained better?

[FenderManDan]

The topic has focused on engines mainly which is interesting in it self, how about the safety, crash worthiness, etc.

Someone mentioned something like "airplanes fly well but not crash well" did that change in C-172?
Did cessna work on crash worthiness? We all know about the air bag in the seatbelt and other seat G force improvements.
What about the cabin cage is that made better than the old ones?


These just some of the other considerations, pilots do not need to spin to get injured. I have seen a number of videos/pics where seemingly in light impact the pilots faces were all smashed up. I read an article recently that Cessna is washing their hands from the product liability in the airframes older than 18 years or something like that.

Cheers

Dan

[Shiny Side Up]

I have seen a number of videos/pics where seemingly in light impact the pilots faces were all smashed up.

You'd probably find that in a majority of those the shoulder harness was impropperly worn, if at all. From what I know, Americans (often citing the shoulder harness as an infringement on their freedoms) are worse at wearing theirs than Canadians, its the whole reason airbags came to be. In the bad ol' 80's, Cessna fought several lawsuits where shoulder harnesses weren't worn resulting in deaths, yet they were available. One of the major factors which resulted in the shutdown of production at that time.

[akoch]

Colonel, I'm wondering if we are talking about the same engines. I implied the certified aviation Rotax engines: the 912. It is used in certified aircraft (Katana etc), and a multitude of LSAs (Virus etc). Yes, these do go beyond TBO and yes, they proved reliable. Like it or not that's the fact by now.

I remember the carb heat is there, it is just never needed as the air is pre-heated (it is incorporated into the engine design). Kind of nice, no ice, and no engine cooling shock effect (also water cooled heads). You can descend at 2000 fps for 10 minutes not worrying about anything.

Don't know anything about the utralight etc...

[Colonel Sanders]

shoulder harness was impropperly worn

That's nice, however plenty of old aircraft don't have shoulder
harnesses, and if you simply add them, TC will put you in jail
for doing a major mod with no paperwork/STC.

Don't know anything about the ultralight

Try to keep it that way.

[akoch]

Don't know anything about the ultralight

Try to keep it that way.

I think I will, something just does not feel right about them to my untrained eye.

But you also don't be as quick calling whoppers around

[Shiny Side Up]

shoulder harness was impropperly worn

That's nice, however plenty of old aircraft don't have shoulder
harnesses, and if you simply add them, TC will put you in jail
for doing a major mod with no paperwork/STC.

I was speaking specifically for the Cessna in this case where in the 172, the shoulder harness was optional equipment, then became standard in the 1970 models and on (due to the propensity of the American public to sue manufacturers for not including something that people could get and would protect them but would opt out of to save a few bucks). You're right in that in many old aircraft it isn't there, contributing to higher likelyhood of injury or death after a crash. It is pretty silly though not to use it if you do have it available, worse yet to think that you should be able to blame your non use of it on someone else.