Heinkel He-162 engine. (1 Viewer)

[evangilder]

Yes the B-49 did suffer from a few problems, and politics. The thought of a dogfight between a P-47 and a B-29 sounds funny, but the altitude makes all the difference for that. Somewhere I have a pic of a B-47 from my dad's days in the air force.

The B-2 has radar absorbing paint, as does the F-117. What does get reflected back is about what a small bird reflects.

 

[the lancaster kicks ass]

whilst in comparison most modern fighters have the radar cross section of a small house.........

 

[delcyros]

Charles, the He-162 with V-tail is the subtype He-162 A-6, not He-162 Z.
The A-8 subtype with Jumo-004 D engines would weight up to 3000 Kg fully equipped. The plus in poweroutput was thought to increase the top speed to 918 Km/h or 570 mp/h. The thrust to weight ratio would be decreased to 0.31 instead of 0.32-0.33 in case of BMW-003 E (overrewed), but the plane would be able to sustain it´s top speed for a much longer time. But this is still better than anything except for the Me-163 and Meteor MK IV.
To the turbines:
The alloys used were tinadur (15% chromium, 15% nickel, 5% titanium and steel) for Jumo-004 B1 and cromadur (without nickel but therefore traces of manganese) for Jumo-004 B4/D/E. The first was thought to be more heat resistant but worser to produce, so it was replaced by cromadur, which could be easily welded instead of deeply drwan for the hollow turbine blades. In the end the later was easier to cool and therefore much more heat resistant than tinadur.
The disadvantage of the Jumo´s in general, beside of the average lifetime was its prone to flameouts under 6.000 rpm. This is mostly because of the fuel regulation system at lower rpm (easy to burn out the turbine blades if too much fuel is injected at low rpm):
A gear driven pump that produced a linear amount of fuel proportion to the engines rpm, the pilots throttle was directly connected to a bypass valve that would recirculate unwanted fuel. Fuel then passed to a centrifugal speed governer that operated another bypass valve. However, if the engines rpm was under 6.000 rpm (set to idle), the speed governer did not take into effect and the throttle bypass was the only fuel flow regulation. The pilots throttle also was connected to a governor by a pressure spring and would regulate the governers rpm setpoint this way. At full throttle, for example, the rpm of a Jumo-004 B4 was at 8875 rpm. Under 6.000 rpm the pilot had to be very careful, because without the governeor it was easy to allow to much fuel entering the combustion chambers and thereby burn them out.
So there can be a dissimilarity between engines rpm and air flow. The BMW-003 had a similar layout but in addition a device that consisted of an aneorid capsule across the compressor stages. This "accelerator valve" regulated the fuel flow in correspondence to the air flow (by pressure) and the governeor had less importance. In the end the actual air flow and spool up time was taken into account, so that the BMW-003 throttle could be handled less gingerly. The Jumo-004 on the other hand had a more sophisticated system to regulate the exhaust nozzle, while the BMW-003 exhaust nozzle was manually controlled.
Further improvements have been under work (some ceramics and thermocuple to reduce fuel flow if temp limits are to be exceeded).
That´s why type testings means something close to zero, the most limiting factor of the lifetime of early jets have been careful handling in the start and spool up phase. That´s one reason why the Jumo-004 B-1 had around 10-25 hours lifetime while the -004 B-4 had around 25-50 and the BMW-003 around 200.

 

[DerAdlerIstGelandet]

The B-2 has radar absorbing paint, as does the F-117. What does get reflected back is about what a small bird reflects.

This I have heard to, but I have read that the B-2 was not as successfull in this in that it was actually seen as the size of a plane on radar. I do not know the truth in this though. Could you clarrify for me.

 

[plan_D]

I've read it has a small signature for the size of the plane but not small enough to avoid RADAR detection - but the shape of the plane allows to easily fly under RADAR.

 

[DerAdlerIstGelandet]

That is what I read thankyou for making more sense out of it.

 

[evangilder]

The best way to describe it is take a playing card and hold it out in front of you. If it is facing you, you see plenty of it. Now look at the edge, you see less. That is pretty much how it is with the B-2. It has a small profile, so if it is heading toward the radar, the cross-section is pretty small, and the radar absorbing paint helps with that. Now if the radar is pointing at a B-2 that is banking or climbing, the cross-section is quite a bit bigger.

 

[DerAdlerIstGelandet]

Nice way to put it.

 

[evangilder]

Thanks, I try to use a simple explanation. Easier to understand for everyone.

 

[FLYBOYJ]

The B-2 has radar absorbing paint, as does the F-117. What does get reflected back is about what a small bird reflects.

This I have heard to, but I have read that the B-2 was not as successfull in this in that it was actually seen as the size of a plane on radar. I do not know the truth in this though. Could you clarrify for me.

This is correct about the B-2 but along with ECMs that are rarely discussed, the B-2 achieves an almost invisible RCS.

I've had the opportunity to work on both aircraft. In mt opinion the -117's RAM material and stealth "system" seemed a little more resilient when compared to the B-2. Also the B-2, being much larger is prone to much more RAM material damage and rework.

Many auto body and fender mechanics were employed by Northrop during the assembly of the aircraft. They were known as "surface prep mechanics."

 

[CharlesBronson]

Charles, the He-162 with V-tail is the subtype He-162 A-6, not He-162 Z.

All right , thanks, I dont have too much books about this plane to compare the data.

 

[me262]

all the z models consisted of 2 fuselages married by means of center wing, AFIK the only one that got in production was the He 111 Z, another example was the Me 109 Z, i'm not sure if this Me got any prototype, others planed : do 635, the he 162, the Ju 290

 

[delcyros]

Never mind, Charles.
After what I read, the BMW-003D (1.100 Kp at 100%) schould replace all BMW-003 A and -003E in later deliveries of the Salamander.
It had a better compressor (the same BBC manufactured one of the -003C) with higher compression and a two stage turbine with some further improvements, like a much reduced specific fuel consumption. It also weighted less than 640 Kg and could very well enhance the performance of the He-162 (or Ar-234C).
I suspect that this couldn´t happen prior to mid 45 and it would be attended moreso in the swept winged versions of the He-162.
But even without it, the He-162 was a first class fighter. If you compare it with Meteor MK-I and MK-III or YP-80A or Vampire (´45). It has the best powerload and the best thrust to weight ratio (second only to the Me-163 and....Surprise! P-59 Airacobra!!!), a decent climb, an excellent top speed (second only to Me-163 and P-80), an unchallanged roll rate (particularly at high speeds) and crit Mach figure. It also has shortcomings: Range, armement and stall behavior (until tail redesigns in jan. 45) beside of material problems like production quality and so on.
It wasn´t until the arrival of the Meteor MK-IV in late 45 that the allies had something superior in the jet field (just my opinion).
Wrong?

 

[FLYBOYJ]

It wasn´t until the arrival of the Meteor MK-IV in late 45 that the allies had something superior in the jet field (just my opinion).
Wrong?

My opinion Del is that although more manevable than the P-80, six 50 cal all nose concentrated would have made toothpicks out of the -162s wings! I think the -162 would of been the Zero of early jets.

 

[delcyros]

Some point, Flyboy.
But now we are digging in the field of durability / survivability of the airplanes. I had the opportunity to read something in advance of this.
He-162:
* comparably high wingload and powerload (wl:around 235-244 Kg/m²)
* wooden wings with metal rudders
* metal fuselage
* designed to sustain a max of 8g (+) and 5 g (-) (destruction limit is about 3 g higher)
* engine mounted above the ss fuel tanks
* ejection seat
* the hittable surface is tiny (below those of the FW-190A)


Meteor-III:
* comparably low wingload and very low powerload (wl: around 177 Kg/m²)
* all metal structure
* ss and protected fuel tanks mounted in the wings (as the engines) and in the fuselage
* designed to sustain a max of 7g (+) and 4g (-) (again, not the destruction limit)
* hittable surface is large (more than two times those of the He-162)

P-80:
* medium wingload and low powerload
* all metal structure
*ss fuel tanks mounted in front of the engine
*designed to sustain a max of 7.5 g(+) and 4g (-) (destruction limit higher)
* hittable surface is medium (around 1.7 times those of the He-162)

ergo: While the He-162 has virtually no armor protection, except for the pilot, the airframe (made of wood) sustains more G forces and is more durable (surprise: A Meteor MK-III crashed because of structural limits during testflights, the wing of MK-IV was enforced (adding 320 Kg to it´s weight) but the FMK-8 needs even further reinforcements to the wings structure...
The P-80 design is much more balanced and If (!) hit by 0.50 M2 (the 0.50 M3 wasn´t serially installed prior to early 1946), damage would be severe but it needs repeated hits to kill the He-162 (as for the Bf-109). Hitting the fuel tank wouldn´t have a big effect. Otherwise could the twin 20mm HE rounds blast a P-80 in pieces with ease. Hitting the fuel tank would lead automaticly to the P-80´s destruction (the gazes would forced to move to the engines and inflame in the end. The problems with unsealed fuel caps underlined the problems, it lead to many accidents). Hitting the wing could cause sereouse damage by deforming the wing surface (blast effects). I have seen pictures of Me-262 beeing hitten in the main fuel tanks without serious effects (it needs a HE round or (questionable) an incidentary round of a 0.50 cal gun to inflame the bad burning german low grade jet fuel.

 

[FLYBOYJ]

Good points! But I have to say a 20mm round hit anywhere isn't heathy. A 20mm hit to a F-80 fuel tank would have to be a direct hit. That area is extrememly reinforced and there is a huge screen in front of the P-80s engine. The P-80s unsealed fuel caps were addressed when many of the A B models were moded into the "C" configuration in the late 1940s.

I believe a concentrated 50 cal hit anywhere on a -162 would destroy it immediately. You're talking 6 50s with a spread of about 3 feet.

 

[delcyros]

Not automaticly. Something very important is the spacial density of fire. The 6 0.50 M2 have a very good density (esspeccially because they are concentrated in the nose and not in the wings) -moreso the 0.50 M3- and they can harm the He-162 if prolonged hitten in the fuselage or the wing.
each round will probably went right through the structure, leaving a hole in the metal fuselage or the wooden frames of the wing. That´s it. If you concentrate enough holes in a certain point (remember, the He-162 is a tiny target, the approaching speeds are high and it´s also highly agile...), the structure will desintegrate (you may cut off the tail for example). Jets are much more simple, esspeccially the engines compared to piston planes and I suspect they can take a huge amount of 0.50 cal rounds (happened in Korea, too), the same goes for the P-80. By the way, the weaponry of the P-80 is well placed and strong enough to deal with anything, I am not going to deny this. However, the 20mm HE rounds of the MG 151/20 have a different effect and the blast effect, if hit, will destroy and inflame anything up to 15 cm beyond the impact point (except if stopped by armor) by means of blast effects. This is probably not enough to deal with heavy bombers but for fighters, esspeccially for the P-80 it´s more than enough to deal with. And less hits are needed to ensure destruction, also. The blast effects are very worrisome for the metal structures in general (esspeccially the wing) as testshots with MG151/20 on metal and wooden wings prooved.
The He-162 could be compared with the Zero, but the Zero missed two important performances, which lead to their fate: A good climb and a good dive capability. The He-162 has it. And while it is true that the plane is nearly unarmored (as was the Zero), it is much more rugged ( it sustains more G forces even with a higher wingload compared to P-80 and Meteor) and not that prone to inflamable by hits.

 

[FLYBOYJ]

The He-162 could be compared with the Zero, but the Zero missed two important performances, which lead to their fate: A good climb and a good dive capability. The He-162 has it. And while it is true that the plane is nearly unarmored (as was the Zero), it is much more rugged ( it sustains more G forces even with a higher wingload compared to P-80 and Meteor) and not that prone to inflamable by hits.

Agree!

 

[delcyros]

The P-80 also was an excellent design, well balanced, fast and quite agile. In the end it was maybe a bit too heavy for it´s engine (or otherwise underpowered) and I estimate that four 20mm instead of six 0.50 would make a better punch, too.
Who knows? The fuselage had a huge diameter, also (depended on the engine). The main problem, beside of air flow seperation at the air intake (causing some flamouts at high g maneouvering) was the fuel regulation and distribution/containing system. But these problems were common for many 1st gen jets.
The Meteor MK III was (my opinion) easy prey for either, He-162 or Me-262.
The MK-IV on the other hand would have been great. Such climb and acceleration impressed me much.
All allied designs miss some aerodynamic points to keep a high maneoverability at high speeds. And the crit mach figure of them is also under average, leaving their opponents in the comfortable situation to break at their own decision.

 

[FLYBOYJ]

The P-80 also was an excellent design, well balanced, fast and quite agile. In the end it was maybe a bit too heavy for it´s engine (or otherwise underpowered) and I estimate that four 20mm instead of six 0.50 would make a better punch, too.
Who knows? The fuselage had a huge diameter, also (depended on the engine). The main problem, beside of air flow seperation at the air intake (causing some flamouts at high g maneouvering) was the fuel regulation and distribution/containing system. But these problems were common for many 1st gen jets.

I got to fly T-33s. If you pulled high Gs you could hear a rumble around the air intakes and I was told you could flame the aircraft out if you did something really crazy. The fuel system problems (on both F80s and T-33s) were fixed in the late 40s, early 50s.

I agree with you on the 4 20mms. I think Lockheed offered a study on this in during the Korean war period.

The engine bay is cavernous, but I think the diameter of all the engines were about the same. Its funny, I've worked in T-33s and Mig-15. when the tail is pulled on both aircraft and you're looking forward in the engine bay its very similar in appearance.