A thought about WWII turbo chargers longevity

[danny_galaga]

Been on my mind awhile. in general, turbos are pretty high wearing machinery. If you have a P47, surely the original turbo charger wouldn't be serviceable. But unlike a lot of other machinery, you wouldn't knock up new parts in a machine shop. So whats happening there? Still lots of NOS to be had? Or adapting something modern from earth moving equipment etc?

[facthunter]

You'd have to  ask people who do this stuff in the trade. I had the turbos on my Piper Commanche twin serviced, but they were not reinstalled as the Plane went on line for training and was more suited to the Job in standard  form.  Nev

[LoonyBob]

Dunno about the P47, but the Piper twins use John Deere parts, washed through a heightened QC process. I did a few APMAs for parts, yonks ago.

[spacesailor]

During that WAR a new,  'Aircraft / Pilot , ' had , 

In the " battle of Britain " 6 yes, SIX, ' MINUTES ' to Live .

Did that turbo have a chance to get to TBO ! .

spacesailor

[LoonyBob]

7 minutes ago, spacesailor said:

During that WAR a new,  'Aircraft / Pilot , ' had , 

In the " battle of Britain " 6 yes, SIX, ' MINUTES ' to Live .

Did that turbo have a chance to get to TBO ! .

spacesailor

I know the average life of a Spit was ~37hrs, and 5~7hrs during the BoB. 6 minutes combat?

 

The Lancaster (Manchester) requirement was supposed to specify a 30-hour life; the B-24 had a - yes - 24hr designed life, which meant most of them were timex after the ferry flight to the UK.

[skippydiesel]

I imagine that there is a significant difference between war time/win at any cost, which means wringing the last fraction of performance from an aircraft engine without concern for its service life  compared with piece time looking for a safe/reliable durable engine run at moderate power.

[LoonyBob]

13 minutes ago, skippydiesel said:

I imagine that there is a significant difference between war time/win at any cost, which means wringing the last fraction of performance from an aircraft engine without concern for its service life  compared with piece time looking for a safe/reliable durable engine run at moderate power.

What kind of negative thinking is this? Have a gander at the below "aircraft" donk...

[onetrack]

In WW2, all the aircraft turbochargers and superchargers were manufactured by Cadillac, as the Cadillac division of GM was the only manufacturing operation in the U.S. that had the ability to produce high RPM, cutting edge technology components that required machining to 1/10,000 of an inch.

There are probably a few NOS turbochargers and superchargers left from WW2. Otherwise, they can be rebuilt using modern engineering machinery, and current high-tech materials.

[facthunter]

Garret was a big name.  Nev

[onetrack]

John Clifford Garrett started the Aircraft Tool and Supply Company in 1936 - but his company only played a small part in WW2, and had nothing to do with turbochargers or superchargers until 1954 - when Caterpillar approached Garrett to supply his newly-developed turbocharger for heavy duty diesel engines, to be fitted to the all-new Caterpillar D9 tractor. So Garrett developed their turbocharger technology from heavy duty diesel applications in the 1950's.

 

https://www.garrettmotion.com/corporate/our-story/#:~:text=The Garrett name ties back,era for the automotive industry.

 

During WW2, Cadillac were the go-to company for cutting edge engineering and advanced technology. Cadillac V8's had hydraulic valve lifters in 1937 - in a side valve V8!

 

William S. Knudsen, president of GM was such a respected figure in manufacturing, he was appointed Director of War Production during WW2 and made a 3-star Lt. General - the only civilian to ever have been given that rank.

Under Knudsen, the car factories in America swivelled all their production over to War equipment (no new cars, or even parts for civilian cars, were built in America between Feb 1942 and Oct 1945), and it was this massive production ability and technological edge that really won the War.

 

Edited December 5, 2023 by onetrack

[onetrack]

Cadillac produced a wide range of high precision components for aircraft, and their smooth V8 engines were manufactured on a large scale for the M5 Stuart and M24 Chaffee tanks.

The Cadillac engines also powered the LVT (Landing Vehicle, Tracked) amphibious vehicle, and the Cadillac factory actually built all the above armoured vehicles in their entirety.

 

Cadillac manufactured 175 high-precision components for the Allison V12 1710 aircraft engine, as well as a range of other aircraft components, such as reduction gearboxes.

I actually have an original copy of the brochure "Cadillac - From Peace to War" that is displayed on the webpage below. Cadillac continued to build U.S. armour right up until after the end of the Vietnam War.

 

http://usautoindustryworldwartwo.com/General Motors/cadillac.htm

[danny_galaga]

I'm not talking about WAS. I'm talking about IS.  All those war birds you see at air shows that run turbo chargers, surely it couldn't be the original? 

[onetrack]

Why not? As long as the turbine blades are not cracked, or haven't come into contact with the housing, there's no reason why they can't be re-used. They're simply soda-blasted and rebalanced.

The shafts can be rebuilt and machined back to the required dimensions.

[LoonyBob]

3 hours ago, danny_galaga said:

I'm not talking about WAS. I'm talking about IS.  All those war birds you see at air shows that run turbo chargers, surely it couldn't be the original? 

The pilots are very careful to keep the TIT down... when's the last time anyone heard a restored as original warbird on full boost?

 

[danny_galaga]

Good point. It was mostly about pressure altitude right? I guess the turbo would hardly be used at all in airshow settings.

 

I remember seeing a lockhead constellation in Darwin, maybe late 90s early 2000s. From Arizona, flying around the world. Those turbos are geared back to the crankshaft or something aren't they for take off power? Something weird anyway. Those turbos would get a good workout I would imagine 

[LoonyBob]

Good point, but a pilot can be nice to them... the Super Connie engines had the exhaust turbines geared back to the crankshaft - it's called a Compound engine, wherein two or more stages of expansion are compounded to extract the power - and the supercharger ditto.

 

All the pilot has to do is limit the manifold pressure on takeoff. The larger problem with that engine is aggressive leaning; they ran them so lean the EGTs dropped, with the side effect of eating plugs, valves, and turbines (they used to watch every plug's voltage spike on a CRO in flight, and note the failed plugs to have them changed during refeulling...).

[danny_galaga]

1 hour ago, LoonyBob said:

Good point, but a pilot can be nice to them... the Super Connie engines had the exhaust turbines geared back to the crankshaft - it's called a Compound engine, wherein two or more stages of expansion are compounded to extract the power - and the supercharger ditto.

 

All the pilot has to do is limit the manifold pressure on takeoff. The larger problem with that engine is aggressive leaning; they ran them so lean the EGTs dropped, with the side effect of eating plugs, valves, and turbines (they used to watch every plug's voltage spike on a CRO in flight, and note the failed plugs to have them changed during refeulling...).

Bloody hell! Thank goodness for jets!

[BrendAn]

2 hours ago, LoonyBob said:

Good point, but a pilot can be nice to them... the Super Connie engines had the exhaust turbines geared back to the crankshaft - it's called a Compound engine, wherein two or more stages of expansion are compounded to extract the power - and the supercharger ditto.

 

All the pilot has to do is limit the manifold pressure on takeoff. The larger problem with that engine is aggressive leaning; they ran them so lean the EGTs dropped, with the side effect of eating plugs, valves, and turbines (they used to watch every plug's voltage spike on a CRO in flight, and note the failed plugs to have them changed during refeulling...).

a friend of a friend was a pilot on the kangaroo route and he said it was rare to land in london or sydney with all engines working.

[facthunter]

Rare to get there without replacing an engine somewhere on the trip. You can fly a lifetime on Jets and never shut an  engine down in anger. They don't have critical RPM's to worry about either. Just don't melt the hot disc down the back or have blades fall off. or hit too many Birds.   Nev

[facthunter]

Turbo Chargers don't have Ball bearings . They usually just run in metal and at very high speeds. Cook them and the oilways carbon up

[LoonyBob]

2 hours ago, facthunter said:

Turbo Chargers don't have Ball bearings . They usually just run in metal and at very high speeds. Cook them and the oilways carbon up

The very early ones used rolling element bearings, as did Whittle, and far too many WW2-era piston engines; I'd think it probably the Corncob turbine did too. Smaller turbos certainly used plain bearings post-WW2, until McInnes invented his clever floating bush (late '60s? early '70s? of course it took a while to get universal...). I'd expect any form of bearing to coke up from heatsoak, in a turbo...

 

I hear youse bragging about jets, but they too get sparkplug problems! Well, some of them...

[facthunter]

Jet engines are the best kept secret in the game. Very easy to manage except when you've got about 60 000 HP on one side and none on the other, you need that big fin and rudder and to press the CORRECT Pedal Hard till you trim it out.  Nev

[facthunter]

Igniters they are and have they got a lot of energy?. Used when starting and in heavy rain. They reckon if you're near the motor outside when starting you easily hear them Cracking away. IF they don't work you'll see a lot of Kero  coming out the back.   Nev

[johnm]

On the subject of P47’s and WW2

 

Reading my last book ……… the Luftwaffe did not have much access to metals such as nickel so their max boost (super or turbo ?) for the ME 109 and FW 190 was say 18000 ft where as the P47 & P51 was something like + 24000 ft

 

The height at which the B17 flying fortress flew at - + 24000 ft

 

A distinct advantage to the allies and their bombing campaign in Europe. A distinct disadvantage to Luftwaffe pilots who had to get up to the B17 height

 

Not something well considered by many ? – these crude technical comments are made for discussion !

[facthunter]

Not sure that's an accurate portrayal.  Recall "beware of the Hun in the Sun". They frequently attacked from above.    Nickel is added to many steel high strength alloys as well as Inconel a turbine blade alloy which has been superseded by better  in later years. Many superchargers are direct gear drive with 2 ratios. It's only turbochargers that need the special turbine blades to take extreme temps.  Nev