Manufacture’s vs. Present day Maintenance Techniques

[Tanker 336]

This topic is obviously directed towards current maintenance techniques/methods that may have been perfected on War birds since WWII. Not looking for specific methods but for those who work on War birds, have some simple jobs like changing a jug & cylinder on a R-2600 gotten any easier? (just an example, not simple by any measure) Just curious to see if things have been simplified /re-engineered over the years for some of the most tedious of jobs.

[PJ]

They certainly haven't gotten any easier on a Harpoon. Even the most mundane of tasks takes forever due to the cramped spaces.


PJ
PV-2 Harpoon "Hot Stuff"
www.amhf.org

[JDK]

Very interesting question! I look forward to seeing some responses.

Some (unqualified) thoughts, and perhaps not strictly on topic...

Stuff like Merlin Fingers in Merlin engines.

CAD for designs re-engineering.

Changes in acceptable materials for use and environmental disposal - e.g. paints, solvents, asbestos firewalls and lagging.

RAF aircraft were built assuming a huge skilled and cheap workforce, so Spitfires were expected to be manhandled on the ground, rather than towed by tractors.

Most warbirds have had the military equipment removed or deactivated, and that is not a 'servicing requirement' after each flight or getting regular testing as it would've in war and peacetime respectively. That said, some recent restorations have working things like tail warning radar refitted, and guns with wiring etc. refitted. But how often is that tested? (Not every 'op', obviously!)

The big one is no warbird operation has a 'supply chain' like an air force had in wartime. Finding parts (phonecalls, e-mails, chasing etc. is a big time eater for the operators, I understand.

Regards,

[John Dupre]

One big change has to be modern oil filters and oils and routine oil changes. It is pretty much an operator's choice whether they install modern filters and oils but I remember reading an article about a C-47 operator in the Northwest that switched from straight weight oils and no oil changes to ashless dispersant multi grade oils with routine oil changes. These were real working aircraft so it didn't take long to get results. The original multidisk oil filter could take from 4 to 5 HOURS to disassemble and clean. After the change it took HALF AN HOUR clean the same filter. The most common non routine maintenance on the engines were cylider changes. These were all R1830 aircraft so 14 cylinders per engine and I think a 1200 hour overhaul limit. Before the switch it was common to replace 10 to 11 cylinders during the run to overhaul, usually for stuck rings. After the change only ONE cylinder change in the 1200 overhaul cycle was common.

So while they more than doubled thier oil purchase in the end they saved money in servicing and cylinder repair costs.

[mlenoch]

Sidebar:

re: Merrlin Fingers--Roush is getting back to the late style Packard cam finger coatings which have thicker chrome surface; he claims a similar or more durable pad than the carbide cam fingers by 'Merrlin'.

Also, the oil filter and oil type changes are necessitated by the fact that present day Merlins are running far longer than their wartime counter parts. I believe the operating time for a wartime engine was 125 hours, if it survived that long. I have heard of some present day Merlins running beyond 1000 hours, before overhaul.

VL

[Enemy Ace]

As a mechanic I have to say that the better quality tools available today (think Snap-on) make working on stuff a lot easier. I inherited some WWII era tools made by Bonney and Snap-on and there's no doubt that the modern tools are made to closer tolerances, fitting the hardware better. Closer tolerances mean no busted knuckles. I can't remember when I last had a fastener round off or strip resulting in blood loss on my part. I would really dread working on stuff for a living with 40's era tools.

[Tanker 336]

In the next six months, the Belle flew missions over France, Belgium, Holland and Germany. She was struck by flak, 20mm cannon shells and machine gun bullets. Every major part of the plane was replaced at least once, including the engines (nine times), both wings, tails and main landing gears. Four of the plane's crew of 10 died during combat.

According to Army records, the plane flew 148 hours, dropping more than 60 tons of bombs, all on daylight missions.

I've often thought, had aircraft engineers knew that their designs were to last into the 21st century (for that matter even 10 years after the war) would they have made common maintenance jobs more user friendly. It's crazy to think in only 148 hours all these parts were replaced/repaired. I can imagine it to owning a Nascar and having to rebuild the engine after every race and sometimes the whole car.

[flyboyj]

Over the years mechanics have developed a hoard of shortcuts and special tools to make a lot of tedious jobs easier. One of my favorite books is "Best OF AMJ Maintenance Tips."

[EDowning]

Someone else has already mentioned tools but I think the modern Borescope has dramatically changed the way I maintain my aiprlanes. I spent the money on a "medical grade" scope with an eight foot articulated probe and it has saved me from doing a lot of needless disassembly and provided me with a capability that would have been impossible back in the day.