Light Aircraft Association

Hi all,

Looking for something else, I found this:

http://www.7ts0.com/

At the very bottom of the page, you can reach directories leading to free download of documentation and spare parts identification catalog for engines. I found it of better value than the junk CDs I purchased once via EEEbay.

If the docs can help,

Bertrand

Many thanks
That was a great find

I fully agree Paul but these are very old engines and hence they are unlikely to keep publishing new manuals. For example I think the latest manual for the TCM O-200 is dated 1984. Certainly in a quick check, in an AD dated 1994 the following text was included:

......."TCM Overhaul Manual Form X-30010, dated January 1984, for TCM Models C75, C85, C90, O-200 and RR C90 and O-200
series engines; as applicable." ie 10 years old!!

The engine manufacturers publish (in the case of TCM, via Aviator Services, http://tcmlink.com/aviator/index.cfm free on the web) Service & Technical Bulletins & Letters which are a really rich source of advice, up to date overhaul info, operating guidelines etc which I have found complement the older manuals very well.

These will also give detail of current / later part numbers of uprated or altered componmts or assemblies.

Regards
Steve

Hi Paul,
at least, it means everybody can still progress or improve its general culture drinking coffee

I am fully aware of the limitation of such out of date documentation. I found it however helpfull for the part identification, even if some of the parts have been superseded by other references.

For free, I cannot offer more than this, it gives at least an idea to non-mecanics of the level of inspection involved for each overhaul and the tools and techniques needed for dismantling/assembly of components.

As I said, I hope this can help, but you are obviously right, I should have mentioned the data should be completed with the relevant updated information.

Bertrand

An other link, found by chance, with AD and BS:

http://www.airplanemanuals.com/Manuals/

Once in each terminal directory, a pdf with active links helps to find the desired doc. For example,

http://www.airplanemanuals.com/Manuals/ ... linder.pdf



Once again, it is a "use it at your own discretion" free of charge documentation, however of better quality that the CD's found on the net for a few bucks.

Doesn't worth a lot, but it is free of charge...

Good coffee table litterature, once again, I know

Bertrand

I was an electrical engineer all my working life but was also a keen diyer on motors for many years.
I've just been having a quick scan of that document and I found some stuff interesting. I know it is not necessary to undertstand machines to operate them but I believe it helps to have an appreciation of how things fit together and work.
Most 4 cylinder cars have a firing order of 1-3-4-2, I wonder why the difference.
I am always amazed at how agricultural and 1940 ish aircraft are but they aren't as stressed as modern machinery.

The firing order is related to the physical configuration of the engine.

Horizontally opposed 4 cylinder four stroke engines fire differently to in-line 4 cylinder four stroke engines because in the former the pistons of the opposing pairs of cylinders move in and out together while in the latter the pistons of the two outer cylinders move up and down together as do the two inner pistons.

This is to provide mechanical balance to the engine so the four power pulses are spread equally throughout each two rotations of the engine otherwise it would vibrate badly.

The ignition firing order has to take this sequence into account.

Think through the pistons' positions in relation to the firing order and it all clicks

I remember as a teenager being very intriqued that the pistons of the Norton Commando four stroke twin cylinder engine moved up and down together (seemingly illogically, though its not) whereas one piston of my two stroke twin Suzuki engine moved up when the other went down (seemingly logical and quite correct).

Took me a while to understand why.

Hi Mark,
As said Steeve, the firing order is directely linked to the geometry of the engine. The dynamic behaviour of the engine will accept a certain crankshaft geometry/firing order to minimize the efforts on crankshaft, and also efforts and momentums in the three dimensions at the engine mounts.
As you are an electrician, you may be familiar to harmonics. For this peculiar subject, the mechanical efforts and momentums during running of the engine are commonly followed on first and second orders. The best common configuration with 0/0/0/0 (theorical F&M, 1st & 2nd °, with perfect balancing of crankshaft + partial weight of con rods) are the 6 cyl, in line or boxer, and V12 60° (Merlins, Jag...) All other configurations will issue some resulting efforts or momentums while engine is running, creating vibrations.


Have a look at this:

http://en.wikipedia.org/wiki/Engine_balance

it is good starter to understand the various types of firing you can find. If you want to know more, you can find some comprehensive documentation in technical handbooks as the Bosch one, dedicated to automotive industry, but going quite far on general and scientific subjects. The book fully explains the theory of dynamic balancing and how you can minor the effects (balancing shafts, for instance). Good "coffee table reading" also


Bertrand