Plans for the Luftwaffe if the war continued ...

[Koopernic]

Some of the changes don't make sense on a technical level. The 3cm MK 108 was a 58kg gun. the 3cm MK 103 was a 141kg gun. You are lucky to replace two MK 108s with one MK 103. The MK 103 ammo was longer and heavier. The gun fired slower. It did have a much higher velocity and longer range but you weren't going to put two of them in either a He 162 or Me 263. Not without taking a substantial performance hit.

The Mauser 213 series guns were great prototypes but how close were they to production? It took the Allies (America, Britain and France) until the early 50s to put into service "copies" of the 213 series guns even with the help of some German engineers and under the threat of the cold war and nuclear bombers. Perhaps the allies had different standards of gun life or mean time/rounds between failures?

The Mk 103 was testing synchronised in the wing root position of the Ta 152C (actually it was a Ta 152B, ground attack version of the C). There are photos floating around on this site. It could also be carried by the Dornier 335. The long barrel MK103 had been 'tried' in the Fw 190 but it couldn't be fitted in the wing root area and was placed in the outer gun position where wing flexture and issues with asymmetrical firing yawing the aircraft arose. I suppose given the electrically ignited primer possible in German guns they might have tried simultaneous firing. The enlarged chord of the wing root of the Ta 152 was to provide for greater armament options and fuel options.

Combat testing of the MG213 or MK213 revolver guns had been assigned for testing to a Fw 190D equipped unit. Mentioned in a Dietmar Hermann book (I think) or maybe volume 3 one of the Eddie Creek trilogy. I have both but my aviation library and I are in different countries. Suprisiningly the revolver guns were capable of synchronisation with a propeller.

The revolver mechanism was supposed to bypass the issue of gun jams under high g manoeuvres, feeding of long belts and the trade-off of muzzle velocity versus rate of fire that affect the various blow back and gas operated systems that have reciprocating motion.

 

[KiwiBiggles]

Suprisingly the revolver guns were capable of synchronisation with a propeller.

That is surprising. Do you know how it was done? Perhaps the rotation rate of the revolver mechanism was geared to the propellor speed itself?

 

[Koopernic]

That is surprising. Do you know how it was done? Perhaps the rotation rate of the revolver mechanism was geared to the propellor speed itself?

Not entirely sure but I can say that in a revolving breach gun that the breech has to line and stop momentarily by a locking mechanism, shoot and then rotate to the next position after the round has cleared the breach. It's not a smooth continuous motion as in the Gatling mechanism.

In the mean time, since there are in fact multiple breeches, say 6, the other breaches are in various stages of simultaneous operation: ejecting the spent case in one breach and inserting a new round in another while while one fires and the others perhaps cool. There is a .gif somewhere. In this case the electrically ignited primer used as an option in German ammunition would do for synchronisation via a rotating switch mechanism, presumably similar to an automotive distributor. These German guns had optional percussion and electrical primers depending on whether they were synchronised or not.

I read the MG151 may have required compressed nitrogen, compressed air and alcohol supply. It apparently cleaned itself. The problem with operating machine guns of blow back or muzzle gases is that the amount of power that can be extracted from these sources is limited and so there is not enough power to overcome a minor jam. Furthermore a round which fails to fire will stop the whole sequence and will need to be cleared. Many combat enounters I have read have the missive 'but my guns had jammed'. These seem to be recocked or cleared by a compressed air mechanism operated in the cockpit. A compressed air supply was needed either way. I suppose a mechanical solenoid could it. Armourers had a lot more on their plate than loading ammunition.

Allied guns that used synchronisation I believe used a hydrostatic or hydraulic mechanism to mechanically interrupt the firing hammer. It was carefully designed like a diesel injection system so that the tubing and piping didn't generate any reflections or standing waves.

Named after some French guy that invented it.

Nevertheless a lot of modern revolver guns seem to be able to operate independently of power, which aids their saleability as back up weapons and weapons for small vehicles and ships tremendously. In such situations there are no 10G manoeuvres happening or long ammunition feeds.

I'm not sure what the ballistics of the MG 213 were, one would assume they were similar to the MG151/20 unless a new more powerful round was introduced. The objective of the research that produced the MG213 was a 1000rpm gun firing 1000m/s. It would be possible to pack slightly more propellant in the existing cartridge and also exploit more of the energy via a longer barrel.

 

[stona]

Not today's but 1957-58

That's a hybrid or dual fuel aircraft. An attempt to overcome the most obvious draw back of rocket powered aircraft.

Rocket powered interceptors are, as Greyman has pointed out, unmanned and called missiles. I never suggested that rocket power per se was a dead end. Once again, I get bored repeating myself, manned rocket powered interceptors were a dead end. The SR.53 just reinforces that, it just took the British, who had an unhealthy obsession with short range point interceptors dating back to the 1930s, ten years to realise. It was still evident in the E E Lightning. At least that SR.53 could manage several minutes at full rocket power, better than any German effort but with the benefit of ten years of additional research.

The Germans would have better put resources into their jet and missile programmes. They already had an operational jet and programmes running for air to ground and ground to air missiles, the latter would have been far more useful than the Me 163, Ba 349 etc. The British would have been better doing the same or, as the Americans, using rocket power experimentally as a step to rather more ambitious targets.

Cheers

Steve

 

[kool kitty89]

Germany was beaten by fall 1944. After that the end was inevitable. The only real question was the cost of prosecuting the war to the end. As with the above posts, I don't think it would have been possible ... unless perhaps something drastic changed in early 1943.

If they has fielded the me 262 in early 1943 in some strength; if Hitler had been more concerned with his people on the Russian Front; if the Type XXI U-Boats had been avilable in numbers at that time (manned, ready, and deployed); perhaps if the Germans had knocked out the British radar and stayed with it as it was rebuilt ... there is a whoile raft of what is that would have to have been seen to in order for the course of the war to have changed.

Given Hitler's nature of keeping the men around him fighting among themselves and not listening to the mlitary advice of his professional military planners (recall that he himslef was a Corporal in WWII, not an officer)... I can't see a way for him to spontaneously turn from a self-centered egomaniac without a conscience into an effective military leader who did proper planning and then carried out the plan.

It seems like a premise somewhat in line with the one here http://www.ww2aircraft.net/forum/aviation/eastern-front-closed-spring-43-a-43115.html would apply. At least as far as the dead of Hitler and a number of other high ranking Nazis and the replacement with a military government that actually had some practical tactical and strategic mind to manage matters. That and it happening in 1943, early enough to actually make some difference.

But there's that exact sort of drastic change in early 1943 you mention.

The real killer for the germans by the latter part of 1944 was not strategic materials, though that was bad enough. it was manpower. They were scraping the barrel by late '43. by late '44 they were down to the old men and boys. In the air, no amount of whiz bangery could escape the fact that their training regime was in tatters, and not recovering. Against the second gen jets like the Meteor F8 and Vampire, Sea Venom they didnt stand a chance, unless they could recover some skills in their mainstream pilots

A military government (a competent one at least) may have gone some way towards reforming the crumbling (and already flawed) training system.

That said the Meteor F8 and Venom are rather out of the question, even the F4 would be pushing things. Vampire and improved F.3 certainly. (long chord nacelles with 2,400 lbf Derwent IV engines) Putting Goblins in the Meteor might have pushed it closer to the F.IV, but unless Rolls Royce started license building them or they expanded dramatically some other way, I don't see how that would be practical without severely curtailing Vampire production. (Nene and Derwent V would take a good deal longer to get mass production ready, and structural modifications for the Meteor IV would delay production as well)

The P-80A would still be notable though, and longer ranged than the Meteor or Vampire.

The Me262's range limitations were not due to fuel quality, they were due to the engine's performance. No first generation jet engines offered their aircraft significant ranges. The Me262 did have decent armor, however the engines and the poorly protected fuel tanks were an issue. The problem here, is that once you start loading the Me262 down with quantities of armor, you're going to suffer a penalty in performance. And the Me262 did have a good rate of climb to begin with.
As far as armament goes, how can you improve on the Mk108?? Those 4 30mm cannon were devastating to anything they touched. The main drawbacks to the 30mm, was ammunition capacity, range and rate of fire. Perhaps consider 4 20mm: the Mg151/20 was lighter, had a higher rate of fire and allowed for a higher ammunition store. The A-1a/U1 and A-1a/U5 were good ideas, but I think that too many weapons in the nose actually limited their effectiveness.

Lighten the nose armament and you need to add ballast (or added armor for the same purpose). As it was, the Me 262 was too tail-heavy to use the rear-most tank without bombs to counter-balance the front. Loading the nose with 3 (four if they fit) heavy MK 103s might do it, though I'd think adding nose racks and plumbing for drop tanks on fighter models would have been more useful. (use the external tanks as ballast and burn off the rear tank first before switching to drops)

A BMW 003 powered Me 262 derivative should have been significantly lighter and less fuel hungry without disturbing CoG (unless I'm mistaken, the swept back wings positioned the engine mounts very close to the center of gravity, so swapping wouldn't change much). Throttle response, reliability, TBO, and total engine life were all better as well. Lower empty weight would mean potential for shorter take-off and landing runs too, even without improvements in thrust/weight.

The Jumo 004D and E models also improved fuel consumption somewhat as well as thrust, altitude performance, lifespan, throttle handling, and reliability.

Focusing on Me 262 production may have made more sense overall than attempting to divert resources to the He 162 at all ... or any of the competing projects.

Presumably this accomplishment includes greater then historical damage to Soviet alliance air forces. How much greater would determine Luftwaffe planning for 1945. For instance, was 1944 Germany able to effective protect synthetic fuel production plants? Is anti-communist alliance able to retain Romanian oil fields? How about Estonian shale oil mines?

Dispersed production using smaller scale fischer-tropsch synthetic fuel plants would have helped offset things to some extent too. (we discussed the possibility of considerably higher yields with shifts towards non-gasoline fuels -alcohols, etc- but that would be more limited with the existing mid/late war infrastructure, still some blends of higher yield synthetic products may have been possible while still meeting existing fuel grade standards close enough)

Feedstocks for such plants could be any sort of coal, oil, natural gas, or biomass (wood, various types of agricultural or municipal waste -some more useful than others) though transportation to get the feedstock to the dispersed sites might complicate logistics with a shift that late. (more centralized production to more dispersed, though potentially shorter transport lines from factory to fuel depot or even more direct routing to where fuel was needed nearest to any given factory)

There never seemed to be a contingency plan to fall back on if any of these adventures failed. Adventures = Battle of France, Battle of Britain, invasion of Russia, etc. etc. etc.

And this blind faith that the Fatherland will prevail in the end, continued all the way until the Red Army was running through the streets of Berlin...

Unrealistic planning and leadership that likely wouldn't have been shared by a military government resulting from a coup. (or some non military ones with similarly practical, competent shifts in leadership) A better 'what if' in that case would be such events occurring before the Battle of Britain and re-evaluating the entire situation along with potential contingency plans. (starting in 1943 leaves an interesting situation too, but certainly far worse and more limiting)

 

[Shortround6]

One could view rocket powered manned interceptors as Ground to Air missiles using human guidance and fusing systems

Once the electronic guidance systems and warheads/fusing got good enough the human was no longer required.

The SR 53 just used a small engine for self recovery and power for auxiliaries (hydraulics and electrics).

 

[Koopernic]

An Me 163B gets to 10000m/33000ft in about 2 minutes. A late war piston fighter about 20 minutes. In a hypothetical situation of a B-29 fast cruising at 300mph and being detected at 100 miles range there is barely time to get to altitude and get an intercept. The situation for advanced piston fighter might be worse. One reason for the Me 163 was as in interceptor of high altitude reconnaissance aircraft. The kinds of Jets the Germans themselves were developing could move nearly 200 miles in 20 minutes.

The problem the Me 163B had was that once up at altitude the 3-5 minutes of fuel remaining was barely enough time to plan and organise a suitable attack run.

There were solutions:
1 The Me 163 rocket motor was indeed fully throttleable. However at low thrust settings it was relatively inefficient, hence a boost followed by coast strategy.

To improve efficiency a second chamber was to be added to the HWK engine, literally a second rocket motor, about 15% the thrust of the main chamber, that shared the mountings, fuel supply, controls. It could be fired simultaneously to the main chamber to slightly increase overall thrust but its main purpose was as a sustainer in level flight. Me 163B with this engine were in fact flight tested.

2 Modest scaled up enlargements of the Me 163 such as the Me 163C or stretches such as the Me 263 (also known as the Ju 248. ) that increased the flying time at altitude considerably to between 15 and 12 minutes respectively allowing vastly increased times for forming an attack solution. These aircraft also offered pressurisation of the cockpit, twice the armament (Me 163C) and undercarriage (Me 263).

These second generation rocket aircraft, which learned from the experience of the first, likely would have been quite effective, particularly at smaller raids, photo reconnaissance attacks etc,

However even at this time it was also noted how tight procedures with the ground controller had to be so as to get an optimal intercept to these fast climbing interceptors. In the Bachem Natter, (which used the same series of rocket engines as the Me 163 including the planed duel chamber system but was launched vertically with the aid of solid rocket boosters) the launch and initial intercept was to be carried out by autopilot integrated with ground based radio control.

Remote control of an autopilot had already been accomplished in the guided missiles Fritz-X and Henschel Hs 293 and was an option in the Mistelle piggy back aircraft. In the Natter (viper) The pilot was there as a sort of terminal homing system and as a means to recover most of the valuable rocket section for reuse. The Natter fired 24 R4M folding fin rockets but if you read Adolf Gallands interrogation and some of the CIOS intelligence files they had plans to add infrared fuses to these. I can't see the value of them in such a small warhead but an slightly enlarged alternative to the R4M was the 70mm Fohn that was entering production could clearly have used a proximity fuse.

Late 1943 the FuMG 64 Mannheim Radar entered service to replace Wurzburg. It was equipped with auto lock. It entered service around the same time as the US designed SCR-584. It was only necessary to track the target, track the interceptor with a second radar tuned to a transponder and though a little bit of mechanical arithmetic then transmit a heading to the autopilot. Wurzburg in fact already had an accessory computer that converted spherical co-ordinates to Cartesian perfect for calculations even without a FLAK predictor.

Not far from and autonomous missile at all. In fact the above guidance system is very effective and was called Rhineland and could have been applied to all German SAMs the Wasserfall in particular. They in fact chose beam riding due to its intrinsic jam resistance when used with an optical fall back.

*************************

As far as the Me 262 range goes: it had a range of 650 miles as an interceptor, which is more than a Tempest V, Any Mark of Spitifre, Early P-47, late P-40, P-39. In terms of time endurance it was obviously less, especially if its superior speed was exploited.

Fuel consumption of a jet at high altitude was not inferior to that of a piston aircraft.

The Me 262 had two 900L fuel tanks. It could carry an additional 200L in a tail tank though due to handling issues it was best to be countered by bombs or drop tanks in the nose to balance the aircraft. Thus fuel supply of the Me 262 was (2 x 900L)internal + (200L)supplementary tank internal + 2x300L(drop tank). IE the 1800L could be increased by 800L or 45% which would increase range by greater than 45%, something like 1600km or 1000 miles.

The methods used by the Saunders Roe were known by BMW.

One variant of the BMW 003 jet engine was the BMW 003R. In this variant a clutch driven by the accessories gearbox was engaged to turn a trio of pumps which supplied propellant to a rocket motor. An Me 262 or Heinkel He 162 so equipped could reach 11000m or so in 1-2 minutes respectively. It also solved a take-off run problem.

Fuel was the standard aviation fuel, nitric acid oxidiser in a conformal belly tank and a small amount of aniline to cause ignition. Nitric acid had many advantages: it was extremely dense as a liquid, it was not cryogenic and it could not decompose. It was of course corrosive but it was thought that this could be handled given there had been several years of research into this propellant.

It's possible, that apart from the Lockheed 'bribe of the century' that the Saunders Roe might have been purchased by the new Luftwaffe given the enormous problem of intercepting Warsaw Pack bombers with little warning.

The development of powerful after burners made rockets unattractive. It took till the late 50s or early 60's for after burning jets such as the J-79 and J-75 in Mach 2 designs to match the Me 163 climb rate.

****************

 

[stona]

One could view rocket powered manned interceptors as Ground to Air missiles using human guidance and fusing systems

I think that's right and exactly what had happened by the mid 1950s. It's why only two SR.53s were ever built. We're lucky one survives!

By 1944/5 the Germans were already working on systems that might have made somewhat more primitive ground to air missiles viable in the very near future. It was certainly something worth pursuing.

Cheers

Steve

 

[Juha]

...As far as the Me 262 range goes: it had a range of 650 miles as an interceptor, which is more than a Tempest V, Any Mark of Spitifre, Early P-47, late P-40, P-39. In terms of time endurance it was obviously less, especially if its superior speed was exploited.

In fact Tempest V had better range and even Spits VII and VIII.

...The Me 262 had two 900L fuel tanks. It could carry an additional 200L in a tail tank though due to handling issues it was best to be countered by bombs or drop tanks in the nose to balance the aircraft. Thus fuel supply of the Me 262 was (2 x 900L)internal + (200L)supplementary tank internal + 2x300L(drop tank). IE the 1800L could be increased by 800L or 45% which would increase range by greater than 45%, something like 1600km or 1000 miles.

Is that so simple? Drop tanks increased fuel load but also drag.

 

[kool kitty89]

The Me 262 had two 900L fuel tanks. It could carry an additional 200L in a tail tank though due to handling issues it was best to be countered by bombs or drop tanks in the nose to balance the aircraft. Thus fuel supply of the Me 262 was (2 x 900L)internal + (200L)supplementary tank internal + 2x300L(drop tank). IE the 1800L could be increased by 800L or 45% which would increase range by greater than 45%, something like 1600km or 1000 miles.

With the added weight of fuel and drag of the drop tanks, I'd think that'd be reduced to closer to 900 miles or less. With BMW 003 1000 might have been possible (lower weight, drag, and slightly better specific fuel consumption). The 004D and E should have improved that somewhat too, though probably not as much as the 003. (probably better for top speed, acceleration, and climb, but the lower weight and size of the 003 should help with range/endurance -and maneuverability, particularly roll rate)

Fuel was the standard aviation fuel, nitric acid oxidiser in a conformal belly tank and a small amount of aniline to cause ignition. Nitric acid had many advantages: it was extremely dense as a liquid, it was not cryogenic and it could not decompose. It was of course corrosive but it was thought that this could be handled given there had been several years of research into this propellant.

I know the Soviets, Americans, and Germans all worked on nitric acid based rockets, but I haven't seen much information regarding nitrogen dioxide (dinitrogen tetroxide) use until well after the war. (denser still and generally less reactive than nitric acid, though needs to be under moderate pressure or kept cold to keep from evaporating similar to light gasoline components -less than butane and considerably less than liquified nitrous oxide, and should be easier to manufacture than nitric acid given NO2 is an intermediate product of industrial nitric acid synthetis)

 

[nuuumannn]

Post war the British saw much value in pursuing jet/rocket propulsion in interceptors because of their rapid climb rate and much experimentation was carried out. Rocket boost motors were built for commercial aircraft as well. The Me 163 played an important part in this, as well as its motor, the Hellmuth Walter Werke was within Britain's area of Germany and was plundered for useful material. Specifications for interceptors were ordered and the Avro 720 was almost at the point of production, but was cancelled before one was completed. https://en.wikipedia.org/wiki/Avro_720

Aside from the SR.53 that Shortround posted, the SR.177 was its big brother and would have been far more potent: https://en.wikipedia.org/wiki/Saunders-Roe_SR.177

 

[Koopernic]

Post war the British saw much value in pursuing jet/rocket propulsion in interceptors because of their rapid climb rate and much experimentation was carried out. Rocket boost motors were built for commercial aircraft as well. The Me 163 played an important part in this, as well as its motor, the Hellmuth Walter Werke was within Britain's area of Germany and was plundered for useful material. Specifications for interceptors were ordered and the Avro 720 was almost at the point of production, but was cancelled before one was completed. https://en.wikipedia.org/wiki/Avro_720

Aside from the SR.53 that Shortround posted, the SR.177 was its big brother and would have been far more potent: https://en.wikipedia.org/wiki/Saunders-Roe_SR.177

The kind of problems the WW2 Luftwaffe faced in WW2 made rocket interceptors attractive. Indeed the Luftwaffe was still interested in them when it faced the Warsaw Pact and the SR.177 was a front runner, maybe only lost out due to political intrigue to the F-104 star fighter. (Note however the US Government actually helped subsidise the SR.177 so good was it thought.

The F-104 J-79 had a very powerful after burner yet it still couldn't match the SR.177.
Performance
Maximum speed: Mach 2.35
Service ceiling: 67,000 ft (20,422 m)
Rate of climb: 60,000 ft/min (300 m/s)
Time to altitude:
brake release to 20,000 ft (6,100 m) - 1 min 27 s
brake release to 40,000 ft (12,000 m) - 2 min 3 s
brake release to 60,000 ft (18,000 m) - 3 min 6 s
brake release to 70,000 ft (21,000 m) - 3 min 51 s


Level acceleration at 80,000 ft (24,000 m) from top of climb at Mach 1.4 to Mach 2 - 1 min 6 s
Radius of turn (at Mach 1·6 at 60,000 ft (18,000 m)) - 24,000 ft (7,300 m)
Rocket full power endurance - 7 minutes
*****

You maybe wouldn't want an all hybrid rocket fighter force but it has its advantages in certain scenarios.

The cryogenic seeker on the Hawker Siddeley Red Top (Firestreak Mark 4) should be very effective in a head on attack against a Mach 2 target approaching at 40,000ft

 

[stona]

]

Aside from the SR.53 that Shortround posted, the SR.177 was its big brother and would have been far more potent: https://en.wikipedia.org/wiki/Saunders-Roe_SR.177

All true, but my salient point is that rocket interceptors were a dead end. None was ever deployed or used operationally by any air force that I'm aware of, other than the WW2 Luftwaffe. Manned rocket interception ended in 1945, if that's not a dead end I don't know what is.
Unmanned developments continued apace, something the Germans might have looked at, but it was really pushing the limits of technology in 1944/45.

Jet powered interceptors were the future of manned aircraft. The situation in Germany in 1944/45 did make rocket powered interceptors an attractive alternative, specifically as a means to counter the aerial assault of the USAAF, but in the long term they were a diversion and a mistake. The Germans already had operational jets and arguably a narrow lead in this technology.

There are about 2,000 jets which might be called interceptors operated today by the USAAF and USN and precisely zero powered by rockets.

Cheers

Steve

 

[kool kitty89]

All true, but my salient point is that rocket interceptors were a dead end. None was ever deployed or used operationally by any air force that I'm aware of, other than the WW2 Luftwaffe. Manned rocket interception ended in 1945, if that's not a dead end I don't know what is.
Unmanned developments continued apace, something the Germans might have looked at, but it was really pushing the limits of technology in 1944/45.

Until SAMs were reliably operational and cost-effective to produce, manned rocket point interceptors or rocket-jet hybrid aircraft still have significant merits.

The R&D and manufacturing/operational resource costs compared to piston and jet powered interceptors relative to their effectiveness (when each type is using optimal tactics) is the more practical matter, of course.


Rocket powered fighters would eventually become obsolete, as would the concept of point interceptors in general, but that didn't occur until well after the end of WWII.

Granted, you could potentially argue for purely jet powered point interceptors as well aiming at much smaller size and higher thrust to weight ratio than the likes of the Me 262 at the expense of range/endurance and perhaps risk greater numbers of landing accidents. (depending on the exact sort of compromises made)

 

[GrauGeist]

It seems to me that the He162 would be a better example than the Me262, actually.

 

[nuuumannn]

but my salient point is that rocket interceptors were a dead end.

You're absolutely right Steve and I agree with your point. The fact was that they were an attractive proposition to some at the time because of their astonishing performance at a time when jet engines couldn't do what a mixed propulsion interceptor could, or at least promised. Th Avro 720 was canned, if I remember correctly because of fears of flying with LOx as the oxidant for the Screamer engine.

 

[stona]

You're absolutely right Steve and I agree with your point. The fact was that they were an attractive proposition to some at the time because of their astonishing performance at a time when jet engines couldn't do what a mixed propulsion interceptor could, or at least promised.

They were very attractive to the Luftwaffe at the time, but then they were trying to deal with a specific problem for which such aircraft did promise a cheap and effective solution. The Ba 349 'Natter' probably best illustrates the point in it's planned attack profile:

The 'Natter', unlike other planned or actual rocket interceptors could not be flown and landed as a glider. The pilot would always have had to take to his parachute. It was a cheap, partly re-usable, solution to a specific problem. It was not really useful in any other scenario other than the point interception of large bomber formations. Frankly, it's probably more fortunate for the men of the Luftwaffe than for those of the USAAF that the system never became operational.

The Me 163 promised more, was slightly less desperate both in conception and operation, but delivered next to nothing.

Cheers

Steve

 

[kool kitty89]

I wonder if a mixed-power jet-rocket arrangement could have been made operational sooner if, instead of engineering a rocket engine that successfully ran on jet fuel (diesel, kerosene, or gasoline), you used rocket fuel as jet fuel. Gas turbines are pretty flexible about the fuels they use, and the blend of hydrated hydrazine and methanol in C-stoff might have worked reasonably well in German turbojets, possibly even with some advantages over kerosene, though the lower energy content would mean considerably higher fuel consumption than kerosene and waste a lot of weight compared to using dedicated fuel tanks. (the oxidizer would only be useful for the rocket in either case)

I suppose the other issue was the Jumo 004 being relatively heavy and even a single engine compromising a good deal of the thrust/weight advantage of a rocket engine. (as well as the sheer size of the 004 compromising some of the streamlining possible with the compact rocket engine)

The 003 would be a bit better, but still rather large and late to production. I'm not sure what BMW's centrifugal P.3303 was like given it seems to have been abandoned before much of anything was built, and Heinkel's engines might have been more interesting had they not been canceled. (or abandoned internally in the case of the early HeS 3 and 6)

I wonder if using external, jettisonable fuel/oxidizer pods for the rocket portion of a mixed-power aircraft would have helped at all for operational status. (use for takeoff and climb, then dumped and using jet power alone, and also not needed to resist chemical attack for extended periods, not making the entire rocket unit droppable like some RATO units and using more fuel/oxidizer than just take-off)

The small size and weight of the rocket engine itself would mean a fairly limited burden to retain fixed to the aircraft. (I know mounting a rocket engine in the tail of the Me 262 was tested, but that was both late and a larger aircraft than I'm thinking of here)

 

[stona]

There was always a lack of power from early rockets and jets. Even the Ba 349 used four Schmidding 109-533 solid fuel rockets to aid it's vertical take off. These ten second fireworks were jettisoned using the recently invented explosive bolt. Heinkel's Karl Butter was the engineer who had come up with the idea and developed the explosive bolt.

Endurance was also a problem. I don't have the 'burn' time for the Me 163 to hand but for early Ba 349s it was 2' 23", to be increased to 4' 36" in later versions.

Cheers

Steve

 

[Shortround6]

The trouble with rockets is that they carried their own oxygen instead of using air. The engine it self was light (very attractive) but the fuel was heavy. The two chamber rocket for the Me 163C weighed 365lbs, a single chamber rocket was lighter.

Unfortunately it consumed fuel at the rate of 19.5lbs of C stoff per lb of thrust per hour and an traditional 40.1 lbs of oxidiser (t-stoff) per lb of thrust per hour, this compares to a Jumo 004 consuming 1.4lbs of fuel per lb of thrust per hour.

even with just the auxiliary chamber alone running at 660lb thrust that is around 655lbs of fuel per minute. IF these numbers are correct the auxiliary chamber alone used fuel at a faster rate than a B-29 climbing out with a heavy load.

The rocket plane could only hope to compete with even very thirsty jets for a very limited amount of time.