Rocket propelled fleas -  (3of3)

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* 1944- Me 163C / Ju 248/ Me 263 / Ju EF 127 Walli

The Me 163C was an improvement of the rustic Me 163 B by these points:

Although the Me 163 had very short endurance, it had originally been even shorter. In the original engine designs the rocket had only one throttle setting, "full on", and burned through its fuel in a few minutes.

Not only did this further limit endurance, in flight testing, pilots found the aircraft quickly exhibited compressibility effects as soon as they levelled off from the climb and speeds picked up.

This led the RLM to demand the addition of a throttle, leading to lengthy delays and a dramatic decrease in fuel economy when throttled.

But by far the biggest problem was the limited fuel load and resulting low endurance. The aircraft had a total power endurance of less than 8 minutes, much of which was used up taking off and climbing to altitude. This gave the aircraft very little time to find and attack the enemy, limiting it to a small area of operations almost directly above its own base. When initially proposed for operational use, there had been talk of building dozens of such bases to provide continual coverage, but as the problems above became clear these plans ended.

The Me 163 C

This problem was addressed in the slightly updated Me 163C. This featured a new dual chamber rocket engine; the upper chamber was tuned for high thrust while the lower was much lower thrust for cruise.

Me 163 C model

In operation, throttling was accomplished by starting or stopping the main engine, which was about four times as powerful as the smaller one. This change greatly simplified the engine, while also retaining much higher efficiency during cruise. Along with slightly increased fuel tankage, the powered endurance improved to about 12 minutes, a 50% improvement.

As the aircraft spent only a short time climbing, this meant the time at combat altitude well over doubled."

These other improvements were welcome too:
Pressurized cockpit.
Bubble canopy.

Three Me 163 C-1a prototypes were planned, but it appears only one was flown, without its intended engine.

The Me 163 D was projected and some photos seem to show it. Dual exhaust chamber and apparently retractable gear, but Me 163 B canopy.

Rare photograph of presumed Me 163 D V1

Me 163 D model

The Ju 248:

Throughout development the RLM proved unhappy with the progress on the 163 project, and eventually decided to transfer development to Heinrich Hertel at Junkers. However, Lippisch remained at Messerschmitt and retained the support of Waldemar Voigt, continuing development of the 163C.

At Junkers, the basic plan of the 163C was followed to produce an even larger design, the Ju 248. It retained the new pressurized cockpit and bubble canopy of the 163C, but had even more fuel tankage and a new retractable landing gear design. On 25 September 1944 a wooden mock-up was shown to officials.

The production version was intended to be powered by the more powerful BMW 708 rocket engine in place of the Walter power plant.

The Me 263:

In November 1944, the aircraft was again redesignated as the Me 263 to show its connection with the Me 163. The two projects also got names - the Ju 248 Flunder (Flounder) and the Me 263 Scholle (Plaice). In early 1945, Junkers proposed its own project, the EF 127 Walli rocket fighter, as a competitor to the Me 163C and Me 263.

For information: the V1 type pulse jet powered Junkers EF 126 "Lilli"

The rocket-powered EF 127.

From left to right: models of the rocket EF 127 "Walli" and of the pulse EF 126 "Lilli"

For information: the jet powered Junkers EF 128 model

Me 263 model

This was typical for the German war industry where companies still tried to outbid each other instead of focusing resources on a common project.

First unpowered flight of the Me 263 V1 was in February 1945. Several more unpowered flights took place that month.

Only 3 prototypes and a mock-up of the Me 263 were finalized, and though 2 were equipped with their power plant in Febr. 1945, none were flown other than as gliders, towed by Me 110.

Test flights were later stopped because of fuel shortages for the Bf 110 towplanes. As the Me 263 was not a part of the Jägernotprogramm (Emergency Fighter Program), it was difficult to get the resources it needed.

For the time being the plane was not expected to enter production but further development was allowed. The V2 and V3 were not yet ready. The V2 was to get the retractable landing gear and the V3 would have the armament built in. The next month both the V1 and the V2 had the two-chambered HWK 109-509C installed, correcting the center-of-gravity problems. They flew only as gliders.

In April, the Americans occupied the plant and captured the three prototypes and the mock-up. The V2 was destroyed but another prototype ended up in the USA. The rest was handled over to the Russians who then created their own Mikoyan-Gurevich I-270 interceptor:

For information: MiG I 270 model, showing a "strange" similitude with the Ju EF 127 !!.

For information: MiG I 270 drawing

* 1944- The VTO Bachem Ba 349 "Natter"

The Bachem Ba 349 Natter (English: Viper, Adder) was a World War II German point-defence rocket powered interceptor, which was to be used in a very similar way to a manned surface-to-air missile. After a VTO (vertical take-off), which eliminated the need for airfields, the majority of the flight to the Allied bombers was to be controlled by an autopilot, essentially because of the rough acceleration of the missile which caused the pilot to suffer the black "curtain" during the first minutes of the flight (which shows at evidence that this rocket plane was more a torture instrument than a glider !!!).

Erich Bachem (who had been the technical manager of the Fieseler aircraft plant )'s BP-20 ("Natter") was a development from a design he had worked on at Fieseler, the Fieseler Fi 166 concept, but considerably more radical than the other submissions.

For information: the Bachem Fi 106 design I: an A5 rocket

boosting a twin jet engined plane; design II:the rocket plane.

It was built using glued and nailed wooden parts with an armour-plated bulkhead and bulletproof glass windshield at the front of the cockpit. The initial plan was to power the machine with a Walter HWK 109-509 A2 rocket motor; however, only the 109-509 A1 unit was available as used in the Me 163 rocket aircraft.

Clearly visible on this photograph are the 24 Hs 297 rockets nose mounting and the rustic look of the Ba 249. The 4 engined plane shown just behind is a Junkers Ju 290 A7(A8?) radar-equipped and, just under the left wing radar antenna, appears a Junkers Ju 388 K or L on background (particular canopy clearly visible).

It had a sea level thrust of 1,700 kg. thrust with its quartet of Schmidding SG34 solid fuel rocket boosters used in its vertical launch to provide an additional thrust of 1,200 × 4 = 4,800 kg for 10 seconds before they burned out and were jettisoned.

The experimental prototypes slid up a 20 m high vertical steel launch tower for a maximum sliding length of 17 m in three guideways, one for each wing tip and one for the lower tip of the ventral tail fin. By the time the aircraft left the tower it was hoped that it would have achieved sufficient speed to allow its aerodynamic surfaces to provide stable flight.

Unmanned Ba 349 launching

The primary mission of the relatively untrained pilot, was to aim the aircraft at its target bomber and fire its armament of 24 Hs 297 Föhn ( or 33 R4M) high explosive rockets, situated in the nose with releasable cone.

The pilot and the fuselage containing the rocket motor would then land under separate parachutes, while the nose section was disposable.

From Dec. 23 1944 up to and including 1 March 1945, 16 prototypes had been used, eight in glider trials and eight in VTO (vertical take off) trials.

The only manned vertical take-off flight on (28 Febr. 1945 ?) 1 March 1945 ended in the death of the test pilot, Lothar Sieber.

Oberleutnant Lothar Siebert climbed into the Ba 349A, strapped in, and rocketed off the launch tower. At about 500 m (1600 ft), the Natter shed its canopy and headrest and the aircraft veered off and flew into the ground, killing Siebert. No cause was determined but the ground crew may have failed to lock the canopy and it could have struck the pilot. Despite the tragedy, more pilots volunteered to fly and the Bachem team launched three flights in March.

Launch tower for Ba 349. The scale is given by the men sizes.

US troops discovering some Ba 349s

A short movie illustrating the inspection by US engineers of some battered Ba 349s and Ruhrstahl X4 missiles:

http://youtu.be/t-P8NjcMemY

The surviving Bachem Ba 349A-1 at the Smithsonian Institution's Paul E. Garber Preservation, Restoration, and Storage Facility in Suitland, Maryland

Another link to a short video regarding the Ba 349:

http://youtu.be/Df-50yROvFs

General characteristics:

Crew: 1
Length: 6 m (19 ft 8 in)
Wingspan: 4 m (13 ft 1 in)
Height: 2.25 m (7 ft 5 in) height without fins
Wing area: 4.7 m2 (51 sq ft)
Empty weight: 880 kg (1,940 lb) fuel expended
Gross weight: 2,232 kg (4,921 lb)
Gross weight boosters jettisoned: 1,769 kg (3,900 lb)
Fuel capacity: 650 kg
Powerplant: 1 × Walter HWK 109-509C-1 bi-fuel rocket motor, 11.2 kN (2,500 lbf) thrust main chamber
2.9 kN (652 lbf) auxiliary chamber
Powerplant: 4 × Schmidding SG 34 solid fuel booster rockets, 4.9 kN (1,100 lbf) thrust each
or 2 x 9.8 kN (2,203 lbf) solid fuel booster rockets
Performance
Maximum speed: 1,000 km/h (621 mph; 540 kn) at 5,000 m (16,404 ft)
Cruising speed: 800 km/h (497 mph; 432 kn)
Range: 60 km (37 mi; 32 nmi) after climb at 3,000 m (9,843 ft)
55 km (34 mi)after climb at 6,000 m (19,685 ft)
42 km (26 mi)after climb at 9,000 m (29,528 ft)
40 km (25 mi)after climb at 10,000 m (32,808 ft)
Endurance: 4.36 minutes at 6,000 m (19,685 ft)
3.15 minutes at 9,000 m (29,528 ft)
Service ceiling: 12,000 m (39,370 ft)
Rate of climb: 190 m/s (37,000 ft/min)
Time to altitude: 62 seconds to 12 km (7.5 mi)
Armament
24 x 73 mm (2.874 in) Henschel Hs 297 Föhn rocket shells
or 33 x 55 mm (2.165 in) R4M rocket shells
or 2 x 30 mm (1.181 in) MK 108 cannon with 30 rpg (proposed)

* For information and investigating ways - other projects of similar concept:

-The Heinkel P1077 "Julia"

 Heinkel P1077 Julia model

-The Focke Wulf Ta 183 Volksjäger (not to be confused with the He 162 single jet plane)

... for information ...and fun: the Ta 183 never left the paper ...

* CONCLUSION

These last chance weapons never saw action til the end of war, and terminate here the 3rd and last post dedicated to rocket interceptor manned planes.

In a nutshell, of all the rocket propelled interceptors we reviewed here, only the Messerschmitt 163 in its A or B versions saw real operational use and combat for a short time (with debatable results) before lack of fuel components left it on the ground.

Hereunder is a list of the main WWII rocket interceptors, whom sizes made them nickname "fleas", as for the Me 163. Did someone count the German flags hereunder ? Once again, one must notice the 30ies-40ies German scientists technological advance ... Thanks a lot to Wikipedia !!!.

Other relative linked posts - Parts 1 and 2:

http://www.modelairplanecollectors.com/forum/topics/jeff20-the-rock...

http://www.modelairplanecollectors.com/forum/topics/jeff21-the-rock...

Take care, all!

Jeff