Heinkel He-162 engine.

[Chocks away!]

I have heard this plane had various problems, from the position of the engine, to the wooden construction, to the tricky handling. Yet i have never heard about problems with the BMW 003. How come it wasn't fitted to, say the Me-262? That aircraft suffered a lot from those Jumos.

 

[delcyros]

The main reason why it wasn´t regularly fitted in the Me-262 airframe was because the Jumo was avaiable earlier. A few prototypes of the Me-262 C were fitted with an BMW-003 R, a standart BMW-003 with added rocket assitance.
Originally the Me-262 was intended to be driven by BMW-003 A. In such a case the airframe could made much lighter (at least 350 Kg), the nacelles for the engines smaller (the BMW-003 had a smaller diameter) and therefore the whole airframe would benefit.
Technically the BMW-003 had a better thrust to weight ratio, was much more reliable, had a longer lifetime and wasn´t that prone to flameouts by changing of throttle settings. But: it had not the same power output (800 Kp compared to 840 Kp (Jumo-004 A at 100%), 828 Kp (-004B1), 840 Kp (-004 B2), 890 Kp(-004 B-3/-4) and 930 Kp(-004D1). And another technical problem never solved in the -003 program was that it was impossible to restart the engine if it was once out (unlike the Jumo-004).
On the other hand it wasn´t until very late in 1944 that BMW-003 have made reliable and if you remind the numbers produced you will find that the Jumo-004 was produced 6-8 times as much. There never were enough -003 to equipp all Me-262 airframes.At least two He-162 prototypes have been equipped with Jumo-004 D, even!

 

[Chocks away!]

Hmm, that's a shame it would be great if Me-262s were reliable.

 

[delcyros]

The unreliability of the Me-262 in general is overstressed a lot. If properly maintened and in case the pilot operates the Jumo´s in the way they had to be operated, the Me-262 is a reliable platform.
Accidents are not uncommon for early jets, the P-80 program proved this. Nobody would say that the P-80 is unreliable.
You may observe the same difficulties for the early Me-262, and moreso for the He-162. Esspeccially the reliability of the Salamander is greatly underestimated. The fuselage was made of metal, the short wings of wood. The same was done for the Me-163 and worked fine. The Ta-183 and Ju-EF128 should also have wooden wings. the Vampire even has a wooden fuselage! The number of accidents for the He-162 program was quite high, but not as high as the Me-262 EKdo´s. With proper improvements both planes would become more reliable. The later Jumo´s (-004 B3/4 and D) worked as well as the BMW-003, while the Jumo´s never reached such a high degree of efficiency (esspeccially because they cannot overrew, the BMW-003A and E could do so: for 30 sec. 923 Kp thrust).

 

[DaveB.inVa]

The later Jumo´s (-004 B3/4 and D) worked as well as the BMW-003, while the Jumo´s never reached such a high degree of efficiency (esspeccially because they cannot overrew, the BMW-003A and E could do so: for 30 sec. 923 Kp thrust).

Thats interesting, I never knew those engines could do that. Do you have any more info about this? Any websites that provide specs?

 

[Chocks away!]

Why would you make a jet out of wood! It sounds opsurd today and yet it worked fine...

 

[me262]

Why would you make a jet out of wood! It sounds opsurd today and yet it worked fine...

the reason for this was that the precarious situation on strategic materials casued by the naval blockade and the constant bombing by the allies, that is the reason for the shoter life of the early jet engines, lack of heat resistant materials, and thats is the difference between the british and german engines, plus that the technology was in their infancy

 

[FLYBOYJ]

Although I question the reliability of both aircraft (the -262 for the engines and using dissimilar metals in it's construction, and the -163 for the use of wood which if damaged must be carefully repaired, we've debuted these points before) The use of wood ushers in something to think about that was probably not even fully realized back then - it absorbs radar waves!

 

[me262]

not really absorbes, just it do not bounce back the radar impulse, an hence do not show in the radarscreen!1
another plane made with wood and the forefather of the b-2 is the HO IX/ Go 229

 

[evangilder]

We have had this discussion before and to say that the Horten is the forebearance to the B-2 is not correct. Jack Northrop had been designing his wing around the same time and if any[/y] aircraft can make that claim, it would be the N9M, not the Ho IX or the Gotha.

The N9M became the XB-35, which later would be developed into the XB-49, a jet powered flying wing. It is said that the XB-49 could turn inside of the P-80 chase plane!!!

 

[me262]

the horten brothers build their first wing sailplane in 1933, their first twing pusher in 1937 and the first jet engine in 44.
about the claim about the performance of the xb 49, it suffered of inestability that is the reason why it did not entered in service

 

[delcyros]

I do agree that the Ho-IX isn´t the forefather of the B-2. Some conceptual similarities are there but both are indigenous projects.
Dave, try
www.warbirdsresourcegroup.org/LRG/he162.html
for verification of the additional thrust for BMW-003-E2 under overrew conditions(2000+ lbs or 9,02 KN thrust). I have not yet found any website to cover exclusivley the jet engine technology aspects, but this page brings it to the He-162 directly.
Overrew wasn´t something unusual, the original Jumo-004 A, designed of rare metals and much chromium could be overrewed to at least 1000 + Kp thust instead of the 840 Kp thrust under 100% power setting.
The later -004B version had problems with vibrations at 9000 rpm, which made it impossible to overrew the engine in the way, the -004 A did (later the max rpm had to be reduced to evevn 8.700 rpm).
The BMW-003 was free of such problems because the smaller diameter of the turbine wheels allowed much higher rpm´s and caused no vibrations.
Several british designs had initially the same problems (W-2B, Dervent-IV) but in the end they have been mastered, mainly thanks to the supeior alloys used for the turbine stage and combustion chambers.
The average lifetime of a BMW-003 combustion chamber was about 200 hours, even the larger BMW-018 jet engine was thought to operate for at least 80 hours at 800 degrees C. For comparison: The improved Jumo-004D had- according to Anselm Franz- a lifetime of about 60 hours.

 

[DaveB.inVa]

It is said that the XB-49 could turn inside of the P-80 chase plane!!!

I've heard that before and certainly believe it. As Im sure you know many big bombers were able to handle better than smaller fighters and such at higher altitudes. There are many references of B-36's being able to turn inside faster jets... if the jets could even get to the B-36's altitude. Paul Tibbets in his book describes mock dogfighting a P-47 at high altitude in a B-29. He said every time the P-47 got near his tail he just had to bank hard into a turn. When the P-47 would try to follow, it would stall out and fall away! This is pretty much how the Lancaster survived with its corkscrew.

It always has suprised me just how manuverable those big bombers and transports really are!

 

[Chocks away!]

Why would you make a jet out of wood! It sounds opsurd today and yet it worked fine...

the reason for this was that the precarious situation on strategic materials casued by the naval blockade and the constant bombing by the allies, that is the reason for the shoter life of the early jet engines, lack of heat resistant materials, and thats is the difference between the british and german engines, plus that the technology was in their infancy

Yeah I know I was just thinking aloud so to speak

 

[KraziKanuK]

According to Gunston in his aero engine book the 004B was good for ~30 hr TBO while the Welland and Derwent were good for 150hr TBO. Both the English engines were type tested to 500hr.

 

[DerAdlerIstGelandet]

I believe all jet engines of that time were not as reliable as they wanted them to be. The just lacked the materials. This was especially true though in the German engines and those of the Me-262.

 

[FLYBOYJ]

It is said that the XB-49 could turn inside of the P-80 chase plane!!!

I've heard that before and certainly believe it. As Im sure you know many big bombers were able to handle better than smaller fighters and such at higher altitudes. There are many references of B-36's being able to turn inside faster jets... if the jets could even get to the B-36's altitude. Paul Tibbets in his book describes mock dogfighting a P-47 at high altitude in a B-29. He said every time the P-47 got near his tail he just had to bank hard into a turn. When the P-47 would try to follow, it would stall out and fall away! This is pretty much how the Lancaster survived with its corkscrew.

It always has suprised me just how manuverable those big bombers and transports really are!

The B-47 was extremely manevuable and there was one planned tactic to deliver nukes in a "lob," flying straight up and allowing the weapon to arc toward the target while the aircraft made its getaway. Eventually these types of maneverus put great stain on the wing attach structure and the -47 starting developing cracks in this area.

 

[me262]

I do agree that the Ho-IX isn´t the forefather of the B-2. Some conceptual similarities are there but both are indigenous projects.

i see the aproch like this:
the H0 IX/Go 229 was made with plywood and hence almost invisible to radar, at that time they did not imagine this concept, and the b-2 invisible to radar

 

[plan_D]

"...not really absorbes, just it do not bounce back the radar impulse..."

If the RADAR waves do not bounce back off the wood then the wood has absorbed the waves.

 

[CharlesBronson]