WW2 engines

[Devourer]

Does anyone know:
what was the average lifespan of a piston engined fighter in WW2?

[NOD2000]

Depends really...

Radials? or inline?
Type of plane?
Condition that it was running in?
Was the Machaninic informed about he engine?
weather that it set through?
Theater that it ran in?
and what point of the war it was?
Fuel grades?
Did the pilot "firewall it" (use WEP) alot?
yah dah yah dah..... you get the point

[vorticon]

long enough to keep you alive anyway...

[dankes]

Engines or aircrafts?

Engines - 25-150 hrs for inline, 50-300 for radial

[Angus]

Would all depend on the use.
Apparantly, some Merlin engines did hundreds of hours on the clock....

[MiloMorai]

What do the manuals say for TBO?

[nuchpatrick]

Merlins suffered alot from foul'd plug's, and faulty radiator doors on the pony's causing over heating issues that lead to shorter life of some merlins.

[HoHun]

Hi Devourer,

>Does anyone know:
what was the average lifespan of a piston engined fighter in WW2?

Taking battle losses into account, Luftwaffe and probably the Soviet VVS, too, didn't expect a fighter to last more than 6 months in combat.

With regard to aging, airframes usually held up better than the engines, which you should take into account when judging aircraft life cycle from engine data.

Regards,

Henning (HoHun)

[bolillo_loco]

from Vees for Victory isbn 0764305611

hours flown before engine needs overhaual and number of hours to overhaul the engine

1945 1st quarter

V-1650 302 flying hours 251 labor hours

V-1710 362 flying hours 134 labor hours

R-1820 591 flying hours 104 labor hours

R-1830 580 flying hours 147 labor hours

R-2800 469 flying hours 242 labor hours

1945 2nd quarter

V-1650 200 flying hours 259 labor hours

V-1710 387 flying hours 104 labor hours

R-1820 609 flying hours 93 labor hours

R-1830 562 flying hours 141 labor hours

R-2800 500 flying hours 241 labor hours

the book states that the figures for the 1650, 1710, and R-2800 are from pursuit aircraft while the R-1820 and R-1830 are from bomber aircraft.

[Devourer]

Great info guys

Sorry i couldnt reply sooner, havent been on the computer for a while.

[niklas]

few components in mechanical engineering are designed to last forever. A car engine designed for 500.000 miles would weight much more than a design for 100.000 miles. It´s all about stress assumption and strength design. Maybe the net will give you some infos if you search for "Wöhlerkurve". The backward gear in a car, for example, is designed to last only about 1000 miles.

So you must take into consideration the stress. When a P-51 did a climb to 30k feet and then starts a 3 hour cruise at low power setting, it´s engine will naturally last longer than a interceptor engine that´s used frequently to climb at high power setting (high temperature) to high altitude. So it shouldn´t be a surprise if engine lifetime of allied escort fighters is much higher than the engines of the 109.

WW2 was a turnaround in overhaul philosophy too. At the end, especially germans with their jet engines tried to introduce a measurement system that depended on applied stress instead of a fixed time intervall. Another example is the order in many handbooks to sent an engine for inspection when a extraordinary high rpm was exceeded (in a dive for example)

But me too, i´m not able to provide exact numbers.

niklas

[MiloMorai]

Late war German piston engines were not made to 'perfection'. With the skilled labour pool gradually decreasing and being replaced by more and more so-called 'slave labour'.

Did not someone say that there was time for the Germans to climb to intercept altitudes. This would not strain the engines.

On the other hand, Allied engines were being perfected contunually.

[HoHun]

Hi Milo,

>Did not someone say that there was time for the Germans to climb to intercept altitudes. This would not strain the engines.

I think it usually depended on how good the GCI guidance was, and how good the prediction for the bomber stream direction.

Power output certainly was a big influence factor. I've heard V-1710 numbers that gave just 100 hours time before overhaul to the engine - that was in New Guinea, where the engines were habitually run at the highest possible power settings to make the best out of the P-40's performance under tropical conditions.

The (exhausting, from the pilot's perspective) long cruising peroids experienced by the escort fighters certainly helped their TBO figures.

Niklas' comment on using better indicators than hours in flight is quite interesting, and actually the Allies used a similar method as the pilots had to manually log the flight time under emergency power. For the V-1650, 1 hour of operation at emergency power required a major engine inspection.

With regard to civilian aircraft, I've read about maintenance intervals being determined by the "tach meter", a counter hooked up to the RPM indicator and actually counting turns of the crank shaft. Display seems to be in hours so that 1 hour of operation at rated RPM reads as 1 "tach meter" hour. The same time of operation at 75% RPM would read as 45 min etc.

I don't know when this was introduced, though I'd guess it was only after WW2.

>On the other hand, Allied engines were being perfected contunually.

Absolutely true, and thanks to (virtually) unlimited strategic materials, they could take this to a degree impossible for the Germans - lack of chromium was one of the problems they faced.

This actually emphasizes the point Niklas makes about design goals - a cheaply produced, short-life engine might be just as good as an expensive long-life engine if the short-lived one doesn't die on you unexpectedly.

I found Bolillo's figures for the V-1710 compared to the Merlin particularly interesting - the V-1710 gave slightly more hours between overhauls, but required only half the maintenance effort!

With regard to production and maintenance effort, I've read the DB605 compared favourably to the Merlin, too, though probably not in overall lifespan :-)

Regards,

Henning (HoHun)

[Angus]

Was the WW2 engine clock a "pure" time measure of engine running time, and is it still today?
At least in my field (tractor work) the engine clock depends on the RPM, typically at 1800 RPM, so 2 hours counting 900 rpm will only count as 1, and max RPM (typically 2300-2600) will be able to deliver the hour in 45 minutes or so.
And engine life? hehe, 10.000 hours maybe.