Can anyone explain the rationale that I can build a VW, Corvair, Scooby Doo - sorry, Subaru - engine for an aircraft from pretty well scratch, splitting cases and rebuilding the bottom end etc but all I can do to a Lycoming or Continental engine is tinker with the cylinders and ancillaries?
It seems barking mad to me that I can build the car derived engines, making all sorts of necessary mods along the way as required to turn it into an aircraft engine which is always, by its very nature, going to be a one-off and, to some extent, an unknown quantity.
If I were to build / rebuild a Lycoming, for example, I would follow a proper, manufacturer supplied, manual that strictly lays out what is acceptable and what is not. I would be using parts supplied by an aircraft engine manufacturer and would not need to be 'making things up' as I went along.
In the US, for experimentals, I believe it is possible to buy a Lycoming (clone) kit and build it oneself. I wonder what the LAA would say if such an engine came into the UK in an imported RV, for example...
"Certified" aircraft engines.
Moderators: John Dean, Moderator
"Certified" aircraft engines.
Rob Swain
If the good Lord had intended man to fly, He would have given him more money.
If the good Lord had intended man to fly, He would have given him more money.
Certified engines.
The reason that you needed a D licence is purely historic, it dates from the ARB and the days of when we flew behind large three row radials of extreme complexity and fragility which were often giving up in service in DC7C and Constellations, also the British home spun complex engins from Bristol and the like.
A 'D' licence was required because the complexity and parts count of these behemoths was immense.
However the bureaucratic mindset of the civil servants in charge could not differentiate between an A65 and a PW turbo-compound treble gang.
An aircraft engine is an aircraft engine. When the CAA came along there was the same mindset an it carried on as before. A US A@P Mechanic is licenced to repair and overhaul all type that he is likely to come across and the proper training includes radials. He is also able to weld which is another ARB throwback. I have built and rebuilt many small aircraft engines but always under the guise of an authorised organisation or an old independent D licence holder, who have all died off now from old age.
The system now is much the same but it involves paying the CAA a large fee to become an approved organisation.
Splitting and rebuilding a small engine is very simple and nothing like the complexity of a modern car engine. Any practicing A@C or competent lawn mower mechanic, could do it, but the mystique of magic pervades the the word Aircraft. Personally I am really fed up not being allowed to do my own work, on my engines, that thirty five years ago I was being paid to do. I even had the service tools to do it.
In the US an experimental engine can be a certified engine with a small difference and no data plate, they can do what they want as long as it can't get back into the certified pool.
Hope that clears up some points. I would like to be ''allowed' to still work on permit engines but The engineering dept would look on that as sin against God or King.
llowed
A 'D' licence was required because the complexity and parts count of these behemoths was immense.
However the bureaucratic mindset of the civil servants in charge could not differentiate between an A65 and a PW turbo-compound treble gang.
An aircraft engine is an aircraft engine. When the CAA came along there was the same mindset an it carried on as before. A US A@P Mechanic is licenced to repair and overhaul all type that he is likely to come across and the proper training includes radials. He is also able to weld which is another ARB throwback. I have built and rebuilt many small aircraft engines but always under the guise of an authorised organisation or an old independent D licence holder, who have all died off now from old age.
The system now is much the same but it involves paying the CAA a large fee to become an approved organisation.
Splitting and rebuilding a small engine is very simple and nothing like the complexity of a modern car engine. Any practicing A@C or competent lawn mower mechanic, could do it, but the mystique of magic pervades the the word Aircraft. Personally I am really fed up not being allowed to do my own work, on my engines, that thirty five years ago I was being paid to do. I even had the service tools to do it.
In the US an experimental engine can be a certified engine with a small difference and no data plate, they can do what they want as long as it can't get back into the certified pool.
Hope that clears up some points. I would like to be ''allowed' to still work on permit engines but The engineering dept would look on that as sin against God or King.
llowed
-
Barry Plumb
- Posts: 29
- Joined: Wed Jan 02, 2008 10:14 am
- Location: Leighton Buzzard
G.Dawes,
Sorry but I just have to make a comment on the accuracy of your post.
To my knowledge no one ever flew behind a three row radial.
P&W made two and four row radials. The largest was the R4460, known as the corn cob. It had 4 rows of 7 cylinders. Wright aeronautical produced the appaling R3350 which was two rows of 9 cylinders ie 18 total. This was the engine that was turbo-compounded with three GE recovery turbines geared to the crankshaft via a variable speed drives. Probably the worlds most unreliable engine ever built (unless someone knows different). The largest ever reciprocating engine made and tested for aircraft use was built by of all people Lycoming. It was 7755 cubic inch capacity (127 litre), and water cooled. This was not a "three row" either.
"D" license holders have not all died off from old age, there are still lots of them about, some of them much younger than me. Just bear in mind that a D license is Annex II only as it is a CAA and not an EASA license. This means that they are pefectly able to work on engines in the LAA fleet of Annex II aircraft with no reference to EASA at all.
Happy landings
Barry Plumb
Sorry but I just have to make a comment on the accuracy of your post.
To my knowledge no one ever flew behind a three row radial.
P&W made two and four row radials. The largest was the R4460, known as the corn cob. It had 4 rows of 7 cylinders. Wright aeronautical produced the appaling R3350 which was two rows of 9 cylinders ie 18 total. This was the engine that was turbo-compounded with three GE recovery turbines geared to the crankshaft via a variable speed drives. Probably the worlds most unreliable engine ever built (unless someone knows different). The largest ever reciprocating engine made and tested for aircraft use was built by of all people Lycoming. It was 7755 cubic inch capacity (127 litre), and water cooled. This was not a "three row" either.
"D" license holders have not all died off from old age, there are still lots of them about, some of them much younger than me. Just bear in mind that a D license is Annex II only as it is a CAA and not an EASA license. This means that they are pefectly able to work on engines in the LAA fleet of Annex II aircraft with no reference to EASA at all.
Happy landings
Barry Plumb
-
Barry Plumb
- Posts: 29
- Joined: Wed Jan 02, 2008 10:14 am
- Location: Leighton Buzzard
GD,
You are absolutely right about those old engines being far too complicated, they must be one of the most complicated mechanisms ever created by man (short of the Hydron Colider!). In the later war years and early post war years the reciprocating engines were coming to the limit of their development, and thank goodness the turbine era started just in time to return some sanity and reliability to commercial aircraft operations.
The old radials could not be operated safely by a mere pilot and the level of training required for the Flight Engineers was considerable. Most of the post war piston propliners were three man crew, and the pilots simply called for power adjustments to be made by the flight engineers. This may sound over complicated by todays standards, but to adjust the power output of one of those "pushed to the limits" radials was a delicate business, with Pitch, Mixture, Timing, Boost adjustments etc required in the correct sequence to avoid the dreaded detonation zone. Multiply all of this up by four, for the number of engines, and you can see that the FE's really earned their corn in those days.
At one of the VAC events recently I had the priviledge to talk to a former BOAC captain who had flown the Boeing 377 Stratocruisers on the north atlantic run for some years. He swears that he never ever came back from New York with the same four engines as he went out with. It was actually quicker and easier to change an engine than to change all of the plugs !
Having said all of the above, I love those big old recips. Radials, Vees, whatever. There is nothing more exciting to me than watching one of those big old beasts on start-up, noise, smoke, smells and the raw feeling of power that they transmit.
Happy Days !!
Kind Regards
Barry Plumb
You are absolutely right about those old engines being far too complicated, they must be one of the most complicated mechanisms ever created by man (short of the Hydron Colider!). In the later war years and early post war years the reciprocating engines were coming to the limit of their development, and thank goodness the turbine era started just in time to return some sanity and reliability to commercial aircraft operations.
The old radials could not be operated safely by a mere pilot and the level of training required for the Flight Engineers was considerable. Most of the post war piston propliners were three man crew, and the pilots simply called for power adjustments to be made by the flight engineers. This may sound over complicated by todays standards, but to adjust the power output of one of those "pushed to the limits" radials was a delicate business, with Pitch, Mixture, Timing, Boost adjustments etc required in the correct sequence to avoid the dreaded detonation zone. Multiply all of this up by four, for the number of engines, and you can see that the FE's really earned their corn in those days.
At one of the VAC events recently I had the priviledge to talk to a former BOAC captain who had flown the Boeing 377 Stratocruisers on the north atlantic run for some years. He swears that he never ever came back from New York with the same four engines as he went out with. It was actually quicker and easier to change an engine than to change all of the plugs !
Having said all of the above, I love those big old recips. Radials, Vees, whatever. There is nothing more exciting to me than watching one of those big old beasts on start-up, noise, smoke, smells and the raw feeling of power that they transmit.
Happy Days !!
Kind Regards
Barry Plumb
-
Nigel Hitchman
- Posts: 357
- Joined: Thu Jan 03, 2008 5:10 pm
- Location: Hinton in the hedges
Yes great those old radials, love to see them flying, you still can at Air Atlantique and a few other aircraft from abroad like the Swiss Connie (which gives rides, but unfortunately not in the UK due to the CAA)
Back to the original question, a friend of mine has rebuilt a number of Continental engines, inc the C-85 on my Cub, all under the eye of an LAA inspector. Each time the inspector has to apply for authority from LAA Engineering to split the crankcase and do the complete rebuild, but it doesnt seem to be a problem to get LAA approval. The inspector is a long time inspector well know to LAA engineering (I dont know if he was licenced, he certainly hasnt worked on any C of A aircraft for many years, so probably not ) so that probably helps.
So it is possible to do this kind of rebuild yourself under a LAA inspector.
The rebuilt engine is not allowed to be "zero timed" officially and the paperwork deficiency wouldnt allow the engine to go back on a C of A aircraft, presumably unless it was overhauled again by an approved overhaul shop.
Back to the original question, a friend of mine has rebuilt a number of Continental engines, inc the C-85 on my Cub, all under the eye of an LAA inspector. Each time the inspector has to apply for authority from LAA Engineering to split the crankcase and do the complete rebuild, but it doesnt seem to be a problem to get LAA approval. The inspector is a long time inspector well know to LAA engineering (I dont know if he was licenced, he certainly hasnt worked on any C of A aircraft for many years, so probably not ) so that probably helps.
So it is possible to do this kind of rebuild yourself under a LAA inspector.
The rebuilt engine is not allowed to be "zero timed" officially and the paperwork deficiency wouldnt allow the engine to go back on a C of A aircraft, presumably unless it was overhauled again by an approved overhaul shop.
I always accepted that as soon as an engine went into a Permit aircraft then that can be regarded as the end of its life for CofA aircraft purposes, certainly without a full overhaul.
Nigel.
Thanks for the information about getting authority from LAA LAA engineering to split the cases. I will bear this in mind in a few hundred hours when 2000 hours are looming.
Oh well - there's some cause for optimism anyway: with the testing of the P-Mags (December's magazine) the flat-earthers who say that only magnetos are acceptable are beginning to be edged out.
Now if we can get after market (aircraft) fuel injection approved for O-320s then we can truly begin to enter the late 20th century!
Nigel.
Thanks for the information about getting authority from LAA LAA engineering to split the cases. I will bear this in mind in a few hundred hours when 2000 hours are looming.
Oh well - there's some cause for optimism anyway: with the testing of the P-Mags (December's magazine) the flat-earthers who say that only magnetos are acceptable are beginning to be edged out.
Now if we can get after market (aircraft) fuel injection approved for O-320s then we can truly begin to enter the late 20th century!
Rob Swain
If the good Lord had intended man to fly, He would have given him more money.
If the good Lord had intended man to fly, He would have given him more money.
-
Steve Brown
- Posts: 257
- Joined: Wed Jan 02, 2008 11:00 am
I fully agree with moving away from the magnetos only approach. But I have to say that I don't think the Emag / P mag architecture is sound.
I dont like the principle of having delicate surface mount printed circuit boards fitted to a hot vibrating engine however much blast cooling is done - the heatsoak after shut down is significant.
I think it would have been better to have compromised a bit on the 'self contained mageneto-like' approach and had the mechanicals and simple sensor and HT coil/distributor in the hot case and have all the electronic and pressure sensing in a small module via a wired / plugin tail. That could be mounted on the cool non vibrating firewall or similar.
Easy for me to say I know & hats off to the P mag guys for getting this far.
I agree fuel injection is necessary for better ecomony & I'd like to see some inovation there too.
I dont like the principle of having delicate surface mount printed circuit boards fitted to a hot vibrating engine however much blast cooling is done - the heatsoak after shut down is significant.
I think it would have been better to have compromised a bit on the 'self contained mageneto-like' approach and had the mechanicals and simple sensor and HT coil/distributor in the hot case and have all the electronic and pressure sensing in a small module via a wired / plugin tail. That could be mounted on the cool non vibrating firewall or similar.
Easy for me to say I know & hats off to the P mag guys for getting this far.
I agree fuel injection is necessary for better ecomony & I'd like to see some inovation there too.
Re: "Certified" aircraft engines.
LAA Eng will look through the logbook and find the last time the crankcase was split, this must be signed out by (at least) an A&P. If its a new engine then I guess if an A&P signed for the build, then that would be ok. If there are no signatures you will very likely have to get a UK approved company to dismantle the engine to find out why it is still working.Rob Swain wrote:In the US, for experimentals, I believe it is possible to buy a Lycoming (clone) kit and build it oneself. I wonder what the LAA would say if such an engine came into the UK in an imported RV, for example...
As for P-mags, I have been running an E-mag on my O-320 for 5 years, 2 of those years on a permit. No problems at all. Could I suggest the gentleman who doesn't like the design takes a look inside of one before declaring the design unsatisfactory? BTW what's wrong with Airflow Performance fuel injection? Simple, reliable, not dependent on electrons ...
Pete
-
Steve Brown
- Posts: 257
- Joined: Wed Jan 02, 2008 11:00 am
Hi - I have indeed had a look inside the E & P mags when I was at Oshkosh in 2005 when the owner went through the design etc with me. That was when I saw the surface mount technology printed circuit board & the whole thing disassembled. Very professionally built & sturdy - I just think electronics and 80-90 deg C temperatures don't mix well.
I'm glad you have had no problems but, for instance, this link shows that there are sensitivities that can manifest themselves even if it is the minority.
http://www.vansairforce.com/community/s ... hp?t=33133
Regards
Steve
I'm glad you have had no problems but, for instance, this link shows that there are sensitivities that can manifest themselves even if it is the minority.
http://www.vansairforce.com/community/s ... hp?t=33133
Regards
Steve