4 engines in AR-234

[chris3]

moin

belive me thay need all 8000 jumo engines for the 262. the live spann of this engines wasn t realy high, less than 25 houers.
and wrong handling causes damages easy too.
so every built 262 used minimum 4 jumos in here live. thats over 5600 jumos!!!!!
and i have read somewehere that only 5000 jumos 004 were built, thats maybe wrong but it becomes clear that the RLM dont have much 004 for the AR234.

cu chris3

[Overlag]

i thought originally they wanted to use the BMW engine in the 262 but production issues early in the stages meant they chased up the Jumo units?

the BMW was a far better unit but also harder to make, ie Jumo turbine blades were hollow to allow them to be air-cooled, and therefor a softer/cheaper metal could be used?
BMW used solid blades of exotic metals so could have a higher RPM and EGT = more power...? in theory of coarse... never really worked out that well.

[chris3]

i thought originally they wanted to use the BMW engine in the 262 but production issues early in the stages meant they chased up the Jumo units?

the BMW was a far better unit but also harder to make, ie Jumo turbine blades were hollow to allow them to be air-cooled, and therefor a softer/cheaper metal could be used?
BMW used solid blades of exotic metals so could have a higher RPM and EGT = more power...? in theory of coarse... never really worked out that well.

moin

thats partly coreckt but not with the bmw engine. first there was the jumo 004a with better material(exotic metals) a livespan over 100houers nearly 100kp more trust and 100kg more weight but because of the leak of material thay made the jumo 004 b with only 25 hours livespann, less 100kp, and less 100kg weight that was the only positv evect, thay were able to do this because of the nice construcktion of this turbine (spezial air-cooled construction).
but of course maby the RLM thought at the beginning about the bmw engines to add these turbines on the 262.
the most powerfull turbines was the henschel turbines at the end of the war. but only a few were built.

cu chris3

[MiloMorai]

There was between 50 and 100 Me262s operational at any one time. How many engines required to keep them operational?

[chris3]

There was between 50 and 100 Me262s operational at any one time. How many engines required to keep them operational?

thats a god question. i gues a minimum of 400. but dont forget these nunbers of 50-100 operational plans includes many more plans.
a operationl squadron need to hold his numbers a static number of fresch plans out of the factorys every week.
and dont forget the testing units, thay did test the 262 since the midel of 1942.
i thing these testingunits take the most part of the produced jumo engines.

cu chris3

[Angus]

Engine life like 10 hrs?

[chris3]

Engine life like 10 hrs?

moin

what do you mean?

cu chris3

[Angus]

I recall engine life being something of 10 hrs. Do not know if that was after 10 hours of operation or after 10 acerage (write-off), since burns were so common. (later cured with throttle regulator, - post war).
Just that.

[MiloMorai]

The 004B's throttle could be operated at any speed above 6000rpm without causing any problems for the engine. Late war the minimum throttle rpm was lowered.

Early engines had short lives but even at 25hrs this would mean at least 20 sorties.

To give some perspective to the 004's engine life early Napier Sabre engines had similar engine life spans.

[Angus]

Thats the one used on the 262 right?
From Rall (He was also testing jets, but that didn't seem to find way into his books), I have only the words about the engines going flame if one was too fast on the throttle. Which was in later jet engines fixed with the regulator.
I knew the Napier Sabre was bad, but not that bad...
BTW, once the radial was ready for the Tempest (I), that was one heck of an engine. Used on the Sea Fury as well, and that one put speed records in solo flights over really long legs.
I can dig up some of this if you like

[Charge]

Please do, and put it in its own thread.

-C+

[Jabberwock]

The 004B's throttle could be operated at any speed above 6000rpm without causing any problems for the engine. Late war the minimum throttle rpm was lowered.

Early engines had short lives but even at 25hrs this would mean at least 20 sorties.

To give some perspective to the 004's engine life early Napier Sabre engines had similar engine life spans.

As laid down in the manual, the inital time between overhauls far Sabres was 25 hours, although on early  flight test this was not often achieved, mosly because of distorition of the sleeve valves. Engine life itself was somewhat higher, although the overhaul was a time consuming job.

Still, the engin did pass the RAFs 2,000 hp/100 hr bench test in mid 1940 with no problems.

After Napier went to Bristol for some metallurgy help, and did some tinkering of their own with the Sabre production process (better production control and wider use of machining), things improved dramatically. TBO was increased to around 100 hours, by 1943 and 150 by 1944.

 

[MiloMorai]

Still, the engin did pass the RAFs 2,000 hp/100 hr bench test in mid 1940 with no problems.

Yes a hand built engine by skilled craftsmen.

Bristol objected and refused to co-operate. Napier thought the idea not worth pursuing. Common sense prevailed and Sabre sleeves were manufactured from nitrided austenitic forgings using Bristol tooling. Centerless grinders diverted from P&W R-2800C production helped with sleeve production.

Graham White

[Grendel]

moin

belive me thay need all 8000 jumo engines for the 262. the live spann of this engines wasn t realy high, less than 25 houers.
and wrong handling causes damages easy too.

You really should try to use more actual facts instead grandmother's urban myths.

There were many different variants of Jumo 004 engines. Yes, the very first engines had operational time of even less than 10 hours. The later engines had increasingly higher operational times between overhauls, 50 hours and upwards.

Besides, the life span - not live spann - was not this. This 25 hours was time between overhauls. You know, maintenance. The engine returned to service after overhaul and was plugged into another plane.

[Angus]

Just wondering. When they "flamed" (wrong use of throtle for instance), could one put them out, and how much was the damage?