Is my old Rover more reliable than small aeroplanes?
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Is my old Rover more reliable than small aeroplanes?
Right,
So it's me again ... I feel partly guilty for occasionally asking questions that make some of you get involved in heated debates.
This one will hopefully be a bit more straight forward to answer as I am new to all of this after all.
I drive a very old car, an old Rover which has never let me know. The engine has never stopped and it also starts first time, every time, even when it's ice cold outside.
Why is it then that we repeatedly hear of engine failures in small aeroplanes?
I realise that an engine failure in an aeroplane is more "dramatic" than an engine failure in a car for obvious reasons, but I also can't help to come to the conlusion that a car's engine is better equipped to do the job it is suppose to than the engine of a small aeroplane.
The way I'm working this out might be backwards and incorrect, but here is my simple theory anyway:
If the same percentage of cars on the road (than aeroplanes in the air) had engine failures then I would "probably" expect to see cars next to the road almost every time I drive on the freeway.
Why is this .. and is my theory completely wrong?
Your thoughts would be appreicated.
S
So it's me again ... I feel partly guilty for occasionally asking questions that make some of you get involved in heated debates.
This one will hopefully be a bit more straight forward to answer as I am new to all of this after all.
I drive a very old car, an old Rover which has never let me know. The engine has never stopped and it also starts first time, every time, even when it's ice cold outside.
Why is it then that we repeatedly hear of engine failures in small aeroplanes?
I realise that an engine failure in an aeroplane is more "dramatic" than an engine failure in a car for obvious reasons, but I also can't help to come to the conlusion that a car's engine is better equipped to do the job it is suppose to than the engine of a small aeroplane.
The way I'm working this out might be backwards and incorrect, but here is my simple theory anyway:
If the same percentage of cars on the road (than aeroplanes in the air) had engine failures then I would "probably" expect to see cars next to the road almost every time I drive on the freeway.
Why is this .. and is my theory completely wrong?
Your thoughts would be appreicated.
S
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The two do different jobs.
Your car engine is unlikely to have to cope with different altitudes and issues such as shock cooling, and most car engines run at 15-20% of max output most of the time, where as the aircraft engine averages anything between 60-100% most of the time.
Most aero engines also run at much lower RPM than car engines, so you wouldn't be able to accommodate a car engine into an aircraft without complex gearing to get them down to the desired RPM.
I see at least 2/3 cars broken down every time I do a reasonable sized trip (say 4 hours) - and it's worse at the height of summer/winter when problems are compounded by the conditions.
Your car engine is unlikely to have to cope with different altitudes and issues such as shock cooling, and most car engines run at 15-20% of max output most of the time, where as the aircraft engine averages anything between 60-100% most of the time.
Most aero engines also run at much lower RPM than car engines, so you wouldn't be able to accommodate a car engine into an aircraft without complex gearing to get them down to the desired RPM.
I see at least 2/3 cars broken down every time I do a reasonable sized trip (say 4 hours) - and it's worse at the height of summer/winter when problems are compounded by the conditions.
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Two things:
a) how many actual failures of engines in certified airplanes to you really hear of - as opposed to the discussions of this possibility?
b) for various reasons, everything in light a/c has evolved incredibly over the years - just look at the avionics available (although not necessarily installed). The one thing that still lives in the 1950s is the engine - with the concomitant reliability. The interesting thing is that nobody has managed to come up with (and certify!) anything better - just look at Thielert.
PS: by 'failure' I mean a mechanical malfunction - not pilot-induced a la running out of fuel, not applying carb heat, etc
a) how many actual failures of engines in certified airplanes to you really hear of - as opposed to the discussions of this possibility?
b) for various reasons, everything in light a/c has evolved incredibly over the years - just look at the avionics available (although not necessarily installed). The one thing that still lives in the 1950s is the engine - with the concomitant reliability. The interesting thing is that nobody has managed to come up with (and certify!) anything better - just look at Thielert.
PS: by 'failure' I mean a mechanical malfunction - not pilot-induced a la running out of fuel, not applying carb heat, etc
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YOur Rover..
OK..I'll take the bait!
1 Whilst you DO hear of light-aircraft engine failures from time to time, you DON'T hear about the hundreds of thousands of flights which are completed without mechanical malfunction.
2 If you spend the next 24 hours driving on the UK motorway network you'll undoubtedly see a few comatose Rovers on the hard shoulder. How many light-aircraft engines will fail in that time? Most likely none!
Happy Christmas etc bm
1 Whilst you DO hear of light-aircraft engine failures from time to time, you DON'T hear about the hundreds of thousands of flights which are completed without mechanical malfunction.
2 If you spend the next 24 hours driving on the UK motorway network you'll undoubtedly see a few comatose Rovers on the hard shoulder. How many light-aircraft engines will fail in that time? Most likely none!
Happy Christmas etc bm
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That would be impossible, Rover never made a car that was worth a ғú¢к.
That sort of proves my point then doesn't it? I know that Rovers aren't "great" cars .. but mine is yet to quit on me of after doing 130 000 miles.
S
That sort of proves my point then doesn't it? I know that Rovers aren't "great" cars .. but mine is yet to quit on me of after doing 130 000 miles.
S
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Lies, damn lies and statistics
You have taken a sample size of 1 and compared it to a sample size of many. So you've got a warped view.
I could, alternatively, consider my flying experience a sample size of 1 and say that aircraft engines never fail.
I think if you took the rover engine owning public as a whole you would find that there are engine failures, just as you do when you take aircraft users as a whole. You could then take the number of failures in each category based on hours and find out which engine fails most. My feeling is it would be the rover car engine. If for no other reason, apart from the MOT, thorough examination is not enforced in Rovers whereas the aircraft has a FSH.
I could, alternatively, consider my flying experience a sample size of 1 and say that aircraft engines never fail.
I think if you took the rover engine owning public as a whole you would find that there are engine failures, just as you do when you take aircraft users as a whole. You could then take the number of failures in each category based on hours and find out which engine fails most. My feeling is it would be the rover car engine. If for no other reason, apart from the MOT, thorough examination is not enforced in Rovers whereas the aircraft has a FSH.
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Maybe I should change the question slightly to try and gage your opinions - to to make clear what I'm trying to understand.
If there were as many light ga aeroplanes in the air as cars on the road (air-space permitted) would the rate of engine failures in cars and aeroplanes have been similar? (Throw in a nice mix of types of light aircraft as you would have different types of cars on the road too).
If not .. why not?
PS - Not that I'm bored at work asking questions like these btw.
If there were as many light ga aeroplanes in the air as cars on the road (air-space permitted) would the rate of engine failures in cars and aeroplanes have been similar? (Throw in a nice mix of types of light aircraft as you would have different types of cars on the road too).
If not .. why not?
PS - Not that I'm bored at work asking questions like these btw.
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Interesting story regarding reliability of cars/aero engines.
An old guy turned up on our forecourt and began to price cars, up to about 5k.
He began asking about reliability and began to short list a few cars and left stating that he will call with me again.
A few days later he called in and bought a little VW polo... nothing strange there you say.
He began telling me the reason he choose it;
After his first viewing he went home, took out the phone book and called a few car breakers/dismantles and the question he asked them was,
1. Do you have an engine for "x" type of vehicle?
2. How many engines have you got for that type
3. How many did you sell in the last year.
He found that the VW engine was in stock at all the breakers and they rarely sell them!.. they had a waiting list for engines for other types (Rover was one of them) and a few others.
He bought the VW Polo on the strength of that argument.... He has bought cars from us since, that was over 10 years ago...I always remember him for that and to be truthful it makes a lot of sense. The old ones can teach us a lesson.
My aircraft uses the Rotax 912 engine and it seems to be the unit of choice at the moment, but the heavier metal will need the Lyc/Continentals and that wont change in the near future.
Does not really help with the OP question, but it proves that some new technology can be un-reliable but a lot of it is excellent... likewise some older technology adopts the KISS method...... that too is hard to beat.
By the way;
130,000 miles is quite low in mileage nowadays, it is not un-common to have cars with 300,000 miles and a few have 500,000 done, engines/transmissions are more reliable now than they ever were.
An old guy turned up on our forecourt and began to price cars, up to about 5k.
He began asking about reliability and began to short list a few cars and left stating that he will call with me again.
A few days later he called in and bought a little VW polo... nothing strange there you say.
He began telling me the reason he choose it;
After his first viewing he went home, took out the phone book and called a few car breakers/dismantles and the question he asked them was,
1. Do you have an engine for "x" type of vehicle?
2. How many engines have you got for that type
3. How many did you sell in the last year.
He found that the VW engine was in stock at all the breakers and they rarely sell them!.. they had a waiting list for engines for other types (Rover was one of them) and a few others.
He bought the VW Polo on the strength of that argument.... He has bought cars from us since, that was over 10 years ago...I always remember him for that and to be truthful it makes a lot of sense. The old ones can teach us a lesson.
My aircraft uses the Rotax 912 engine and it seems to be the unit of choice at the moment, but the heavier metal will need the Lyc/Continentals and that wont change in the near future.
Does not really help with the OP question, but it proves that some new technology can be un-reliable but a lot of it is excellent... likewise some older technology adopts the KISS method...... that too is hard to beat.
By the way;
130,000 miles is quite low in mileage nowadays, it is not un-common to have cars with 300,000 miles and a few have 500,000 done, engines/transmissions are more reliable now than they ever were.
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Lucky, aren't you? - I've known more than one person who has gone through a series of old Rovers, usually owning more than one of them at a time so there's a supply of bits to repair the regular breakdowns. One of these people got applauded whenever he actually managed to turn up at something, as he usually failed to make it to the party or whatever due to yet another breakdown.
And why don't you hear about car engine failures? - why should you, the driver just coasts to the side of the road and calls the AA, that's hardly going to make the local newspaper even, is it. I have had several engine failures in cars, and whilst the ones in the outside lane of a crowded motorway seemed dramatic at the time they're still not the sort of thing anyone would have heard about.
And why don't you hear about car engine failures? - why should you, the driver just coasts to the side of the road and calls the AA, that's hardly going to make the local newspaper even, is it. I have had several engine failures in cars, and whilst the ones in the outside lane of a crowded motorway seemed dramatic at the time they're still not the sort of thing anyone would have heard about.
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Well, 130,000 miles at an average speed of, say, 60mph (yes Rovers will do that) is more than 2000 hours.
Also, I can increase the sample size at a stroke to 2 Rovers with 130,000 failure-free miles (what else would a Sunday Driver use?)
So, more than 4000 hours without a failure.
We know there are some 4000 hour chaps out there, so what's your experience of MTBF?
Yours
SD
PS I HAVE had a Vauxhall engine put a rod through the block at 30 mph
PPS I have also had a VW engine run its bearings on the M4
PPPS and my old 4.2 Jag, but I was doing 120 (in 1977)
Also, I can increase the sample size at a stroke to 2 Rovers with 130,000 failure-free miles (what else would a Sunday Driver use?)
So, more than 4000 hours without a failure.
We know there are some 4000 hour chaps out there, so what's your experience of MTBF?
Yours
SD
PS I HAVE had a Vauxhall engine put a rod through the block at 30 mph
PPS I have also had a VW engine run its bearings on the M4
PPPS and my old 4.2 Jag, but I was doing 120 (in 1977)
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Oh dear Sunday Driver, sorry to hear about all your unfortunate incidents, although I think the issue may be you rather than what you drive!
How many aircraft engines have you broken?
How many aircraft engines have you broken?
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Why is it then that we repeatedly hear of engine failures in small aeroplanes?
Engine failures in planes are extremely rare - certainly in the proper types if well maintained etc.
Cars rarely get catastrophic failures (conrods flying out through the bonnet) but they get loads of electronic failures (my car's speedo sometimes shows 180mph and when that happens, the speed limiter shuts down the ignition - really handy on an automatic which cannot be restarted unless in the PARK position with the rear axle locked, and it's going to be a b*stard to get fixed because it is intermittent), loads of coolant leaks, etc.
This subject has been done to death but basically car engines run at 10-20% of max power 99% of the time, whereas aero engines run at 60-70% continuously. And they are mostly aircooled (for low weight and avoidance of unreliable and heavy liquid coolant systems) which requires reasonably smart thermal management, yet most planes don't have the instrumentation installed to enable this. So many aero engines need early maintenance.
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Gertrude ..
You might slightly be missing the point. I appreciate that you are likely to hear of more aircraft engine failures ... I think I even said in my post that these are usually more "dramatic" for obvious reasons.
What I would like to know is ..
Is the average car engine better at driving than the average light aircraft engine is at flying? I.E are cars generally more reliable at what they do.
I'm not trying to compare apples with pairs ... but I also know that there are similarities between the engines.
One answer that sounded quite decent to me was by Slopey who actually gave a reason as to why it might be more challenging for an aircraft engine to never fail (referring to altitude & the level of power that it is operated at).
S
You might slightly be missing the point. I appreciate that you are likely to hear of more aircraft engine failures ... I think I even said in my post that these are usually more "dramatic" for obvious reasons.
What I would like to know is ..
Is the average car engine better at driving than the average light aircraft engine is at flying? I.E are cars generally more reliable at what they do.
I'm not trying to compare apples with pairs ... but I also know that there are similarities between the engines.
One answer that sounded quite decent to me was by Slopey who actually gave a reason as to why it might be more challenging for an aircraft engine to never fail (referring to altitude & the level of power that it is operated at).
S
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Is the average car engine better at driving than the average light aircraft engine is at flying? I.E are cars generally more reliable at what they do.
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I'm guessing the Messrs Lyc & Cont good improve the design and reliability of their engines but would face loads of problems trying get them certified in this modern litigious World; kind of better the devil you know than the devil you don't! It's amazing how bad an aero engine has to be before it really fails. I remember seeing a Gypsy Major where every piston ring on all four cylinders had broken up and were circulating round the engine and yet the aircraft was still flying - just using a bit more oil than usual.
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They could certainly improve known problem spots e.g. Lyco valve guides but I think they are afraid of admitting that the old design was defective.
IMHO it isn't so much product liability or certification, as the fact that a lot of people would start pressing them for special deals on overhauls of the pre-modification engines. In another business, I would adopt the same cautious attitude, perhaps.
Lyco have finally done away with the really major weakness which was their "disappearing tappets", by bringing in roller tappets. But they have ensured that you need new crankcases to have these, which ensures that it will almost never be an economic retrofit.
IMHO it isn't so much product liability or certification, as the fact that a lot of people would start pressing them for special deals on overhauls of the pre-modification engines. In another business, I would adopt the same cautious attitude, perhaps.
Lyco have finally done away with the really major weakness which was their "disappearing tappets", by bringing in roller tappets. But they have ensured that you need new crankcases to have these, which ensures that it will almost never be an economic retrofit.
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Is the average car engine better at driving than the average light aircraft engine is at flying?
If car engines fail whilst driving a hundred times as often as light aircraft engines fail whilst flying they might each be equally "good" at doing the job they were bought for at the price at which they were sold and meeting the safety expectations of the general public.