Bullet Proof Engines?

[NoWingsAttached]

I was having a conversation with another flying buddy just days prior to this thread being started. He brought up a valid point: There is no difference in reliability nor longevity of a Lycoming, Rotax 912, or Continental over any other decent 4-stroke motor. The difference is aircraft certified engines have all been provided to us with schedules of maintenance for when to replace the parts that wear out or may fail. Engines all wear out and fail at some point in time, and predictability is the one and only thing that separates certifiable from non-certifiable. I thought this was a valid point worth passing along.

[NoWingsAttached]

Originally Posted by birdy

on the 912, fuel pumps, throttle linkages, 2 carbs, cooling systms, ignitions,.......... .
The only non redundent part on me ferel is the nut on the stick.

You changed something to make the throttle cable redundant after yours broke? Smart bird. Perhaps you could share a photo or two of the upgrade, or a good description.

[Jason O]

Originally Posted by birdy

on the 912, fuel pumps, throttle linkages, 2 carbs, cooling systms, ignitions,.......... .
The only non redundent part on me ferel is the nut on the stick.

All the items you mention (except ignition as I posted) are not engine parts but external of the engine. The 912 I have does not have 2 fuel pumps on the engine. One is electric and external. If one of the carbs quits working, the engine will not run so I dont know if you call that redundent. Almost all of the items you mention could be on a alternate engine without any change to the engine at all. Lack of redundant systems on an engine installation (throttle cables, fuel pumps) are the choice of the installer, not an engine feature.

Jason

[birdy]

If one of the carbs quits working, the engine will not run so I dont know if you call that redundent
You assuming this or have you had one fall off.
Iv had one fail, and the machine flew just fine,..........just.

[Jason O]

Originally Posted by birdy

If one of the carbs quits working, the engine will not run so I dont know if you call that redundent
You assuming this or have you had one fall off.
Iv had one fail, and the machine flew just fine,..........just.

I was assuming that the engine would not keep an aircraft in the air on 2 cylinders, I stand corrected.

Jason

[birdy]

Itd depends on a few things Jason, like power to weight and your situation wen you droped the carb.
The ferels 912 is usualy only cruisen at bout 45-50% power, so with one dead carb it will just do it.

The occasion im refern to was wen i asked for full power to climb out of a dam, surrounded by tall trees.
Wen i opened the throttle, it shook like a gut shot dog and JUST staggered over the trees.
Was prepared to chop it n land soons i cleared the timber, but wen i backed off, it came good again. Hit the throttle again and it died again.
Limped to a spot where i could TO again and landed, shut it off and found a small slither of copper/ brass in one carb bowl.
Turned out that wen i asked for full fuel, the main jet sucked this up n it bloked the jet. Back off n it would fall out again.
So, as it turned out, THIS machine can JUST climb out of a hole on one carb.

[Heron]

So, excess power comes handy, right?
Heron

[cbonnerup]

Originally Posted by Heron

So, excess power comes handy, right?
Heron

I would argue the need for excess 'reliability' in any situation...a systems approach.
Not desiring to bump to a dramatic thread, but a good read of Al Wick's data on the Soob Conversions is instructive of the reliability issue...my opinion only please.
http://www.ez.org/pages/alwick/index_files/Page877.htm

Chris

[Fly Army]

Originally Posted by Heron

So, excess power comes handy, right?
Heron

That's been Boeing's philosophy on almost every aircraft they've ever made. Sadly not the 787 however.

[rfsolutions]

The long block design of all of these engines are all on par as far as reliability is concerned ( modem automotive maybe even higher). As mentioned it's the systems associated with the long block that affects reliability. The aircraft old timers are air cooled, redundant ignition, mechanical and electrical fuel pumps with a direct drive to the Propellar.

The rotax 912 has a reliable long block, a proven gearbox PRSU for Propellar drive, can have redundant fuel pumps. It's liquid cooled but can avoid seizing the engine with cylinder head cooling fins if coolant is lost (redundancy) and a redundant ignition system.

That's what makes these engines reliable.

If an automotive conversion ( like a Subaru) uses the stock computer that has been tricked into thinking it's still running a car. The computer will typically protect the engine if a major fault is detected or sensed which will typically reduce power to a non flight worthy condition (I've experienced this more than once). There is not a large selection of PRSUs to reduce RPM enough to couple a prop to the crankshaft and their reliability is typically unproven. If an automotive cooling system fails, the engine is not long lived.

I've explored building an automotive conversion with enough redundant reliable systems to match the proven direct drive old timers. Unfortunately the cost is on par with a known and proven quantity. It just doesn't make financial sense.

I have and will keep flying my automotive conversions but only over areas I can land if the engine quits. I'll save mountain flying for proven power plants.

[WHY]

Certified aircraft engine reliability ?????? Look what happened when you take a Continental 0-300 and make it a GO-0-300 and crank it up to a "screaming" 3200 rpm on the engine and 2400 on the prop

Tony

[James]

I am old school, I would not fly any engine that relies on a computer. Keep it simple, engine, carb and prop, that is all I need. A female military pilot from my aera died when the duel FADAC on her chopper mal functioned and slammed her and her co pilot to the ground.

James Lee - TN

[Resasi]

People fly, people die, old school, new school.

Fadec is on the majority of the worlds airliners and flying is one of the safe forms of travel.

[Rotor Rooter]

You get what you pay for, and IMO the key word on this thread is 'tolerance'.

Many decades ago I worked at a General Motors engine plant. Every so often they shut down a specific component manufacturing line, such as crankshafts, and rebuilt the tolerances in all the machines in the line.

On restart they would send the initial production to warehousing to be used for replacement parts. Then the following production would be sent directly to engine assembly.

Quite naturally, the tolerances of the parts in an engine are extremely dependant on the tolerances of the machines that make the parts. However, the frequency and quality used in rebuilding the line is expensive.

I've been driving the same Porsche, which has an aluminum V8 engine, for 30 years and have never had anything replaced in the engine, transmission or differential. Infact, if all the costs related to the car were amoritized over the 30-year period it would be quite an inexpensive car.

What is a life worth?


Dave

[WaspAir]

Originally Posted by WHY

Certified aircraft engine reliability ?????? Look what happened when you take a Continental 0-300 and make it a GO-0-300 and crank it up to a "screaming" 3200 rpm on the engine and 2400 on the prop

Tony

Here's what Wikipedia has to say about it, making it sound like operator error:

The GO-300's tainted reputation was largely undeserved, since its problems were the result of pilots who were unfamiliar with gear reduction engines simply not operating the engine as specified in the C-175 Pilot's Operating Handbook. Pilots unfamiliar with the engine often operated the engine at the low RPM settings (2300-2700) appropriate to direct-drive engines, while the 175's Operating Handbook called for cruising at 2900 RPM. The low RPM caused harmonic vibration in the reduction gear between the quill shaft (that turned the propeller) and crankshaft, and the low power resulted in low airspeeds that prevented the engine's air-cooling system from operating effectively . . . resulting in chronic reliability problems for engines not operated at the recommended power settings.