Brand new... Old Yank metal -v- new plastic fantastic.

[soay]

Originally Posted by IO540

The real problem with the old Lycos etc is that they use thin metal sections (to save weight) and need careful management to avoid cracked cylinders etc. Lycoming etc have also had dreadful QA but that is a separate issue. Some of the design is also crap e.g. camshafts that don't get oil on them other than by splashing up, but this is nothing to do with efficiency...
Attempts to use diesel car engines (Thielert, and ex Merc engine) have not been successful. The result is heavier than the old iron and so far much less reliable.

That reads like you are contradicting yourself. What data do you have to support the statement that Thielerts are much less reliable?

Have you read the Aviation Consumer report on Thielert reliability? In it, Frank Thielert is quoted as saying that "in 630,000 flight hours, the 1.7 engines have experienced 22 inflight shutdowns and two accidents, but no fatalities or injuries. That pencils out to about 3.5 shutdowns per 100,000 hours, which Thielert maintains is only one-third the rate of other piston aircraft engines". However, Aviation Consumer say "We simply don’t have credible failure rate data for avgas engines", so it's like comparing apples with oranges.

[Rod1]

G-EMMA

Could we tempt you with a T67M?

Rod1

[IO540]

Soay

I suggest you speak privately to people who operate the DA40/42, preferably those who operate fleets of them. Many of them have had half the fleet grounded with engine issues, much of the time.

My guess is that the Thielert issues have been covered up as is traditional in this business. I am sending you a PM with another example.

I don't want to look like I am gloating in this - I'd like nothing more than a new sexy looking composite avtur burning IFR machine to succeed in this decrepit marketplace which so desperately cries out for a new sexy looking go-places machine, to draw in some new blood and new attitudes. I wish this wasn't true. But it really does look like there is some way to go.

If you just rent a DA42 ad hoc, I doubt you will see any problems.

There is a lot of data for avgas engines, over decades, but it hasn't been collected. It's been dispersed among hundreds of engine rebuilders, 99.9% of whom don't post on pprune and it will never be retrieved. If people like Lyco have data, and they probably do, they are not going to publish it. It would reveal that while outright breakages are very rare, a large % of their engines don't make TBO due to various combinations of crap QA and engine mismanagement by pilots.

[Contacttower]

na the Firefly doesn't have the appeal, might try one though

Bulldog beats the Firefly any day...much better roll rate and a nice weighty feel.

[Contacttower]

Times seem to be a changing so would anyone buy a brand new aircraft based on a 40 or 50 year old design from Cessna / Piper / Beech / Mooney /etc rather than one of the newer designs?

I wouldn't buy a new Piper or Cessna...IMHO the Warrior and C172 still have some merit as trainers but for anything else they are poor value for money, have bad fuel burn and represent old technology.

Beech and Mooney are perhaps slightly different, they may be as old as the Cessnas and Pipers in terms of when they first flew but they still carry a slightly 'macho' image of a plane with a great big engine and lots of complicated stuff inside of them. I suspect the few that can afford to buy them buy them with the idea in mind that they are somehow 'more of a man' than the people who opt for the 'soft' Cirrus or Diamond. Mooney and Beech have their solid reputations on their side as well which will continue to count for a lot.

Also the new stuff always seems to get bad press, OBA took the plunge and invested in a big fleet of Liberty XL2s...and look how much good that did them.

If I had the money I'd buy something old...some big old taildragger like a Cessna 180/185 or something really crazy like an AN-2. Aviation has never really been about making more ergonomic and easier planes to fly.

[ProfChrisReed]

Composite airframe life

IO540 wrote:

But composites won't be here 30 years from now like the 1970s spamcans are still here.

My 39-year old composite glider is still going strong, and looks good for another 39 years so far as anyone can see.

It has needed no repairs to the structure from aging (knocks are different, of course), though I do know of hinges (rudder, aileron) beginning to delaminate and needing to be reattached on other composite gliders - these were all noticed on pre-flight or at annual inspections, and were degrading slowly enough not to be a hazard in flight from sudden detaching of control surfaces. This seems to me to be equivalent to losing a rivet or two on an aluminium aircraft.

What does deteriorate on composites is the gel coat if exposed to UV, which is why composite gliders are either kept in trailers or hangared. Modern paints seem to provide as good a finish as gel coat, and are much more UV resistant. However, I can't help with knowledge whether a composite aircraft left outside would suffer airframe deterioration, though I doubt it.

I'm quite certain that a composite aircraft which lives in a hangar when not flying has a lifetime of 50 years +. Many models of glider have had lifetime extensions to 12,000 flying hours, based on their condition at 3,000, 6,000 and 9,000 hours.

[IO540]

The reason I don't think the Diamond type certified composite planes will not be around 30 years from now is not that the material will particularly degrade.

It's just that repairs are harder on composite than on metal.

Recently I was visiting an aircraft factory where they make both ally and composite hulls and the engineer showed me a tiny crack on a composite roof, near a hinge attachment point. He said this will be a major repair job taking several days, whereas on ally you would just rivet a reinforcing plate in there.

If you look at the average 1970s training spamcan, it has had a lot of little repairs. I would suspect that with composites, the trend will be to not do so many.

OTOH once the present ally fleet falls apart (say 10-20yrs from now) and replacements from the USA become scarce, schools will be forced to move to composites as the mainstream. I have no idea how that might pan out.

In private ownership, with careful use, I am sure composites are just fine.

[scooter boy]

plastic vs aluminium

One clear winner:

Mooney Acclaim-S.

TKS/TCAS/G1000

end of.

SB

[IFMU]

Originally Posted by IO540

I don't think liability and certification are the problems they are constantly made out to be.

Certification isn't a problem, just send money. To certify a brand new airplane to part 23 (GA fixed wing), or part 27 (normal category rotorcraft), or part 29 (transport category rotorcraft) costs a large amount of money. I'm sure the same is true of part 25 (Boeing and Airbus territory). Ultimately, to satisfy the bureaucracy of the FAA, you have to generate a weight of paper about equal to the GW of the airplane. This takes man-hours, it takes money. Ultimately you have to earn that money back. That takes profit. So, you either have to make big bucks on each aircraft you sell, or sell a lot of them, or preferably both. I bet that is a lot easier in a part 25 aircraft than a part 23. This is one of the reasons we have light sport aircraft today. Not as much paperwork, not as much costs to recoup. We are still seeing some good LSA's hit the streets, but of course they have limitations too. Limitations on what you can do with them, payload, and speed. Good fun flying airplanes for recreation.

Personally, I don't see the lack of new airframes coming out of Cessna as an indication that they are a bad aircraft company. They have done a realistic assessment of the market, the profit they have to make, and are still building a slightly updated 50 year old airframe. On the other hand, I give some of the more recent companies, like Robinson, Cirrus, and Columbia tremendous credit for having a go at it. Never mind that Columbia is just about to be sold to Cessna.

As far as liability, here in the US it is a problem. It's a bigger problem the bigger the company. The lawyers don't always go after who's 'fault' it really is, just after the deepest pockets. In some ways a startup company is a better vehicle to take the liability risk, as when they start they are all hopes, dreams, debt, and a risky business plan. Take a company like Cessna, with deep pockets, an order book full of Citations, and a huge parent company. Somebody flies a C172 into a granite cloud and for sure lawyers are going to go for the big prize. Sadly one of the prices we pay for our freedoms and our legal system.

-- IFMU

[IFMU]

Originally Posted by ProfChrisReed

My 39-year old composite glider is still going strong, and looks good for another 39 years so far as anyone can see.
...

What does deteriorate on composites is the gel coat if exposed to UV, which is why composite gliders are either kept in trailers or hangared. Modern paints seem to provide as good a finish as gel coat, and are much more UV resistant. However, I can't help with knowledge whether a composite aircraft left outside would suffer airframe deterioration, though I doubt it.

I think it is a huge difference that the gliders are kept out of the weather and sun. There is a good reason we put them back in the boxes after we fly. I bet that if you kept your ship outside for 39 years and didn't keep after the paint, that sooner or later that degredation would start to extend to the structure of the glider. The paint on my (sheetmetal) Blanik is pretty poor after 10 years outside, but the sun has little effect on the hard anodized skins. That's one advantage of sheetmetal, assuming you don't end up with corrosion.

-- IFMU

[IFMU]

Originally Posted by IO540

It's just that repairs are harder on composite than on metal.

There is a glider repair business here in town that takes wrecks and puts them back together. Tails busted off, cracked cockpits, wing damage, they do it all.

At the company where I work we work both in composite and sheetmetal. One of the promises of composite is easier maintanability. I think this is because you don't have to reform the parts, just glue them back together. Then you effectively bond on doublers, analagous to riveting on a patch, but when it's finished it's easier to make it look good.

I don't think it's harder, necessarily. But I do think there are a lot more sheet metal mechanics than there are good composite technicians around today. The good composite guys make it look easy. If, as an aviation community, everybody abandons sheetmetal and goes with composite aircraft, the maintenance industry will support that move. They already do for gliders.

-- IFMU

[Rod1]

There is a document on how to repair composite structures on the PFA site. I had to do a repair on my composite tank, and I have to say it was very simple and much quicker than it would have been if it had been metal. The problem is most engineers are used to repairing metal and are not regularly repairing composites. I am sure when most airframes went from fabric to metal the engineers said it was harder to repair the metal.

My old gliding club had a repair shop which was forever repairing the club fleet and composites did not present any problems. Do not assume all composite gliders are kept in hangers or trailers, almost all of the Grob motor gliders I know of are kept outside. Composite tec has come on a long way since it first became popular in the early 1960’s.

Rod1

[tangovictor]

before departing with my money on a new composite 3axis microlight, I went and spoke with many glider people, most of which leave them out all year round, in our UK weather, with no problems at all, + speak to any composite repairer, and here that most boats are made from the same stuff, and where do boats live ?

[PapaNovGolf]

I'm also very new to GA and have been intrigued about why GA planes still look the same after decades of the same design and technology. And I'm always curious why some of the know-how and lessons learned in the automotive industry cannot be transplanted to GA. Economies of scale through better manufacturing/quality would see prices gradually reduce to a manageable level for the average consumer, ergo more people would get involved in flying. Right now, I don't know about you, but who's got money to shell out to buy an old, clapped out plane that would cost a stack more to maintain?

[Pilot DAR]

why GA planes still look the same after decades of the same design and technology

It's not that there are not new ideas of merit, but decades of research have resulted in the designs which work, and have all of the "bugs" out. Add to that the cost to certify a new design, after enduring the cost of getting the bugs out, and it is temping to just continue the same old way of doing things, with a design which has long since paid for itself.

New concepts are coming - slowly, but the costs are high, and people are slow to line up to pay a half million for an aircraft which has little more capability than the 40 year old one of the same model.

but who's got money to shell out to buy an old, clapped out plane that would cost a stack more to maintain?

The same person who has the money to shell out for five to ten times the cost for a brand mew one. Using a Cessna 182 as an example, I bought a 1979 model in April, in excellent condition with good times on everything, and flew it home completely snag free for 28 hours. Cost $75,000. Were I to buy a brand new 182, I'm betting $400,000? No differences in performance or capability between the two.

The operating cost of the new one will be quite a bit more. You're insuring a much more expensive aircraft, so much greater premiums. There are systems on the new aircraft (airbag seatbelts for example) which have expensive maintenance requirements, which the older aircraft just do not have. Otherwise, the costs of the older aircraft will not likely be any greater, other than some "wear and tear" items, and maybe corrosion if you're not careful. The 182 I bought will be completely rebuilt so as to be "new", and will still come in under the cost of a brand new 182 wheel plane, though it will now be a diesel amphibian. It will go onward to it's new home in another country.

Aside from the diesel amphibian aspect, this is an "apples to apples" comparison. If you're going to look at a new generation plane, things are different, though the costs are probably comparible. The foregoing is a micro examination of a very large issue. There are lots of other factors.

Also consider that the "old" sheet metal construction is extremely well understood, and easily inspected and repaired. This is sometimes not so straight forward for newer construction methods. They too are repairable, but often not with the desired ease locally.

see prices gradually reduce to a manageable level for the average consumer, ergo more people would get involved in flying

Nice an idea as it is, I very much doubt that we will ever see the cost to manufacture a new aircraft actually compete with the cost of a good to exellent older one, even with some rebuild. Yes, new ones will sell, but not to those people looking for the most economical way to fly. Add to that the cost to get yourself to the point where you're licensed to fly your own aircraft, which itself, is never going to decrease noticably, and "manageable level for the average consumer" is not on the horizon.

It simply costs a minimum to get airborne, and no economy of scale can reduce that much.

[cumulusrider]

In the gliding world I looked after a fleet of gliders for a number of years.
They ranges from wood and fabricwings/metal tube frame fusalage K8s to glass/carbon composite Discus and Ventus. The aircraft with the least maintenance problems and reliablity were the mid 80s composite aircraft.

Over the last few years several major ADs on corrosion on steel and alloy structures in gliders In fact I believe the Blaniks (all metal construction) are currently grounded worldwide due to corrosion problems. This is causing

The earliest glass gliders, Phoebus, libelle etc. are still in regular use.

Yes a lot of gliders are kept on trailers or hangers but we have 20 odd larger gliders live outdoors under covers for 8 months of the year.

I consider composite structure is likely to outlast an alloy one if protected from UV whilst not in use, and re-gelled every 20 yrs or so.

[Pilot DAR]

and aren't subject to crazy government maintenance bureaucracy.

Hmmm, I hope there is no intent to convey that the maintenance standard should be lesser for a non-certified aircraft.... An RV-x aircraft (only as an example) should have a very similar maintenance program to many GA aircraft with similar complexity (Grumman Tiger, for example).

The crazy government people, and delegates like me, who spend time assuring that maintenance information for aircraft is appropriate, and well documented, hope that all aircraft are effectively maintained. The basis of certification (or not) for an aircraft should not influence the content of it's maintenance program, the nature and systems of the aircraft should form the basis to determine the appropriate maintenance.

And, of course, proper documentation of the maintenance accomplished is always important, regardless of the type of aircraft upon which the maintenance was accomplished, or who accomplished it.

[Genghis the Engineer]

Originally Posted by Pilot DAR

Hmmm, I hope there is no intent to convey that the maintenance standard should be lesser for a non-certified aircraft.... An RV-x aircraft (only as an example) should have a very similar maintenance program to many GA aircraft with similar complexity (Grumman Tiger, for example).

The crazy government people, and delegates like me, who spend time assuring that maintenance information for aircraft is appropriate, and well documented, hope that all aircraft are effectively maintained. The basis of certification (or not) for an aircraft should not influence the content of it's maintenance program, the nature and systems of the aircraft should form the basis to determine the appropriate maintenance.

And, of course, proper documentation of the maintenance accomplished is always important, regardless of the type of aircraft upon which the maintenance was accomplished, or who accomplished it.

The standards don't want to be significantly less, but the beaurocratic overheads can be.

The EASA system keeps adding management complexity without apparently adding safety (indeed, the paper chasing versus allowing good technicians/engineers to just get on with maintaining flying machines they understand often seems to be anti-safety).

Various sub-ICAO systems such as those of the LAA and BMAA do seem to manage equivalent standards and safety, whilst massively cutting the management aspects.

G

[Ex FSO GRIFFO]

G'Day Pilot DAR,

Can I enquire what sort of diesel you are putting in your 182?
And do you require a reduction gearbox?
And would that be water cooled?
Just curious is all....

Cheers

[Croqueteer]

I think future problems will be caused by building down to a weight to meet unrealistic targets in the small aircraft field. There is something to be said for a bit of over engineering to give airframes a long life like the current older generation.