DONE @p.3 +++ 1:72 Do 217 F-0 w. SG 104 "Münchhausen", a maritime nutcracker

Dizzyfugu · December 27, 2021, 03:30:53 AM

Well, from what I could find out about the mission profile of the SG 104 and its potentialo carriers, it would certainly have been restricted to daytime missions, because it would have been fired in a dive. Even though taking the carrier aircraft - a clumsy medium bomber - into a dive with an angle of up to 80° and then firing the weapon onto a battleship that was throwing anything at it would have taken some serious guts...

Pellson · December 27, 2021, 04:22:52 AM

I'm sure you already have had a think on this, but didn't the black go out of the balkenkreuzes earlier than -44?

I LOVE the camo, btw.

AndrewF · December 27, 2021, 05:03:26 AM

Extra points for complete insanity on this one...

Dizzyfugu · December 27, 2021, 05:05:00 AM

Well, since this represents a kind of prototype or pre-production aircraft, I stuck to "traditional" markings and just used simplified/un-edged crosses on the hull, together with full-scale codes (around 1944 the initial two letters for the unit code were frequently reduced in size). The paint scheme is to reflect this special status, too, even though it was adapted from a contemporary He 177 that was operated over the Atlantic. The result looks better than expected, though, with the rather pale colors and without the typical cammo mottles on flanks and fin. I was afraid that it would look rather boring, but the overall impression is really good, the scheme suits the Do 217 - esp. with its "extensions" - well.

Dizzyfugu · December 28, 2021, 02:00:29 AM

Finished thsi one yesterday, and the final exciting moment ended positively: the extended tail wheel, only roughly measured, turned out to be long enough so that the gun's rear end does not touch the ground. Still a tight affair, but it works.

Pictures next - in-flight scenes will the challenging because this thing is relatively large and there was no room for a ventral display holder. Hmmm...

Pellson · December 28, 2021, 02:58:37 AM

Quote from: Dizzyfugu on December 27, 2021, 05:05:00 AM
Well, since this represents a kind of prototype or pre-production aircraft, I stuck to "traditional" markings and just used simplified/un-edged crosses on the hull, together with full-scale codes (around 1944 the initial two letters for the unit code were frequently reduced in size). The paint scheme is to reflect this special status, too, even though it was adapted from a contemporary He 177 that was operated over the Atlantic. The result looks better than expected, though, with the rather pale colors and without the typical cammo mottles on flanks and fin. I was afraid that it would look rather boring, but the overall impression is really good, the scheme suits the Do 217 - esp. with its "extensions" - well.

As said - you had thought about the crosses..

Much looking forward to the photos of the completed aircraft. When I had my WWII period, in my teens, the Do 217 K was a given favourite, being fast, sleek and oh so German with it's all glazed nose.

Dizzyfugu · December 28, 2021, 03:55:37 AM

Photo session concluded without major accidents.

Dizzyfugu · December 29, 2021, 03:31:26 AM

Some scenes have to be re-shooted, light color went awry, and I'll try to create a "dive attack" shot. Not easy, though, the model is relatively large for my normal setups.

Dizzyfugu · December 29, 2021, 07:07:30 AM

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

Some background:
The Sondergerät SG104 "Münchhausen" was a German airborne recoillless 355.6 mm (14-inch) caliber gun, intended to engage even the roughest enemy battleships, primarily those of the Royal Navy. The design of this unusual and massive weapon began in 1939. The rationale behind it was that a battleship's most vulnerable part was the deck – a flat surface, with relatively thin armor (as typical hits were expected on the flanks) and ideally with vital targets underneath, so that a single, good hit would cripple of even destroy a ship. The purpose of such a high angle of attack was likely to allow the projectile to penetrate the target ship's deck, where the ship's armor, if there was any, would have been much thinner than the armor on its sidesHowever, hitting the deck properly with another ship's main gun was not easy, since it could only be affected through indirect hits and the typical angle of the attack from aballistic shot would not necessarily be ideal for deep penetration, esp. at long range.
The solution to this problem: ensure that the heavy projectile would hit its target directly from above, ideally at a very steep angle. To achieve this, the gun with battleship caliber was "relocated" from a carrier ship or a coastal battery onto an aircraft – specifically to a type that was capable of dive-bombing, a feature that almost any German bomber model of the time offered.

Firing such a heavy weapon caused a lot fo problems, which were severe even if the gun was mounted on a ship or on land. To compensate for such a large-caliber gun's recoil and to make firing a 14 in shell (which alone weighed around almost 700 kg/1.550 lb, plus the charge) from a relatively light airframe feasible, the respective gun had to be as light as possible and avoid any recoil, which would easily tear an aircraft – even a bomber – apart upon firing. Therefore, the Gerät 104 was designed as a recoilless cannon. Its firing system involved venting the same amount of the weapon's propellant gas for its round to the rear of the launch tube (which was open at both ends), in the same fashion as a rocket launcher. This created a forward directed momentum which was nearly equal to the rearward momentum (recoil) imparted to the system by accelerating the projectile itself. The balance thus created did not leave much net momentum to be imparted to the weapon's mounting or the carrying airframe in the form of felt recoil. A further share of the recoil induced by the moving round itself could be compensated by a muzzle brake which re-directed a part of the firing gases backwards. Since recoil had been mostly negated, a heavy and complex recoil damping mechanism was not necessary – even though the weapon itself was huge and heavy.

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

Work on the "Münchhausen" device (a secret project handle after a fictional German nobleman created by the German writer Rudolf Erich Raspe in the late 18th century who reputedly had ridden on a cannonball between enemy frontlines), was done by Rheinmetall-Borsig and lasted until 1941. The first test of a prototype weapon was conducted on 9th of September 1940 in Unterlüss with a satisfactory result, even though the weapon was only mounted onto an open rack and not integrated into an airframe yet. At that time, potential carriers were the Ju 88, the Dornier Do 217 and the new Junkers Ju 288. Even though the system's efficacy was doubted, the prospect of delivering a single, fatal blow to an important , armored arget superseded any doubts at the RLM, and the project was greenlit in early 1942 for the next stage: the integration of the Sondergerät 104 into an existing airframe. The Ju 88 and its successor, the Ju 188, turned out to be too light and lacked carrying capacity for the complete, loaded weapon, and the favored Ju 288 was never produced, so that only the Dornier Do 217 or the bigger He 177 remained as a suitable carriers. The Do 217 was eventually chosen because it had the biggest payload and the airframe was proven and readily available.

After calculations had verified that the designed 14 in rifle would have effectively no recoil, preliminary tests with dumm airframes were carried out. After ground trials with a Do 217 E day bomber to check recoil and blast effects on the airframe, the development and production of a limited Nullserie (pre-production series) of the dedicated Do 217 F variant for field tests and eventual operational use against British sea and land targets was ordered in April 1942.

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

The resulting Do 217 F-0 was based on the late "E" bomber variant and powered by a pair of BMW 801 radial engines. It was, however, heavily modified for its unique weapon and the highly specialized mission profile: upon arriving at the zone of operation at high altitude, the aircraft would initiate a dive with an angle of attack between 50° and 80° from the horizontal, firing the SG 104 at an altitude between 6,000 and 2,000 meters. The flight time of the projectile could range from 16.0 seconds for a shot from an altitude of 6,000 meters at a 50° angle to just 4.4 seconds for a shot from 2.000 meters at an almost vertical 80° angle. Muzzle velocity of the SG 104 was only 300 m/s, but, prior to impact, the effective velocity of the projectile was projected to range between 449 and 468 m/s (1,616 to 1,674 km/h). Together with the round's weight of roughly 700 kg (1.550 lb) and a hardened tip, this would still ensure a high penetration potential.

The operational Sondergerät 104 had an empty mass of 2.780 kg (6,123 lb) and its complete 14 inch double cartridge weighed around 1.600 kg (3,525 lb). The loaded mass of the weapon was 4,237 kg, stretching the limits of the Do 217's load capacity to the maximum, so that some armor and less vital pieces of equipment were deleted. Crew and defensive armament were reduced to a minimum.
Even though there had been plans to integrate the wepaon into the airframe (on the Ju 288), the Gerät 104 was on the Do 217 F-0 mounted externally and occupied the whole space under the aircraft, precluding any use of the bomb bay. The latter was occupied by the Gerät 104's complex mount, which extended to the outside under a streamlined fairing and held the weapon at a distance from the airframe. Between the mount's struts inside of the fuselage, an additional fuel tank for balance reasons was added, too.

The gun's center, where the heavy round was carried, was positioned under the aircraft's center of gravity, so that the gun barrel markedly protruded from under the aircraft's nose. To make enough space, the Do 217 Es bomb aimer's ventral gondola and his rearward-facing defensive position under the cockpit were omitted and faired over. The nose section was also totally different: the original extensive glazing (the so-called "Kampfkopf") was replaced by a smaller, conventional canopy, similar to the later Do 217 J and N night fighter versions, together with a solid nose - the original glass panels would have easily shattered upon firing the gun, esp. in a steep high-speed dive. A "Lotfernrohr" bomb aiming device was still installed in a streamlined and protected fairing, though, so that the navigator could guide the pilot during the approach to the target and during the attack run.
To stabilize the heavy aircraft during its attack and to time- and safely pull out of the dive, a massive mechanical dive brake was mounted at the extended tail tip, which unfolded with four "petals". A charecteristic stabilizing dorsal strake was added between the twin fins, too.

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

The ventral area behind the gun's rear-facing muzzle received additional metal plating and blast guiding vanes, after trials in late 1940 had revealed that firing the SG 104 could easily damage the Do 217's tail structure, esp. all of the tail surfaces' rudders and the fins' lower ends in particular. Due to all this extra weight, the Do 217 F-0's defensive armament consisted only of a single 13 mm MG 131 machine gun in a manually operated dorsal position behind the cockpit cabin, which offered space for a crew of three. A fixed 15 mm MG 151 autocannon was mounted in the nose, too, a weapon with a long barrel for extended range and accuracy. It was not an offensive weapon, though, rather intended as an aiming aid for the SG 104 because it was loaded with tracer bullets: during the final phase of the attack dive, the pilot kept firing the MG 151, and the bullet trail showed if he was on target to fire the SG 104 when the right altitude/range had been reached.

The first Do 217 F-0 was flown and tested in late 1943, and after some detail changes the type was cleared for a limited production run of ten aircraft in January 1944. The first operational machine was delivered to a dedicated testing commando, the Erprobungskommando 104 "Münchhausen", also known as "Sonderkommando Münchhausen" or simply "E-Staffel 104". The unit was based at Bordeaux/Merignac and directly attached to the KG 40's as a staff flight. At that time, KG 40 operated Do 217 and He 177 bombers and frequently flew reconnaissance and anti-shipping missions over the Atlantic west of France, up to the British west and southern coast, equipped with experimental Henschel Hs 293 glide bombs.

Initial flights confirmed that the Do 217 airframe was burdened with the SG 104 to its limits, the already rather sluggish aircraft (the Do 217 had generally a high wing loading and was not easy to fly) lost anything that was left of what could be called agility. It needed an experienced pilot to handle it safely, esp. during start and landing. It is no wonder that two Do 217 F-0s suffered ground accidents during the first two weeks of operations, but the machines could be repaired, resume the test program and carry out attack missions.
However, during one of the first test shots with the weapon, one Do 217 F-0 lost its complete tail section though the gun blast, and the aircraft crashed into the Bay of Biscay, killing the complete crew.

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

On 4th or April 1944 the first "hot" attack against an enemy ship was executed in the Celtic Sea off of Brest, against a convoy of 20 ships homeward bound from Gibraltar. The attack was not successful, though, the shot missing its target, and the German bomber was attacked and heavily damaged by British Bristol Beaufighters that had been deployed to protect the ships. The Do 217F-0 eventually crashed and sank into the Atlantic before it could reach land again.

A couple of days later, on 10th of April, the first attempt to attack and destroy a land target was undertaken: two Do 217 F-0s took off to attack Bouldnor Battery, an armored British artillery position located on the Isle of Wight. One machine had to abort the attack due to oil leakages, the second Do 217 F-0 eventually reached its target and made a shallow attack run, but heavy fog obscured the location and the otherwise successful shot missed the fortification. Upon return to its home base the aircraft was intercepted by RAF fighters over the Channel and heavily damaged, even though German fighters deployed from France came to the rescue, fought the British attackers off and escorted the limping Do 217 F-0 back to its home base.

These events revealed that the overall SG 104 concept was generally feasible, but also showed that the Do 217 F-0 was very vulnerable without air superiority or a suitable escort, so that new tactics had to be developed. One consequence was that further Do 217 F-0 deployments were now supported by V/KG 40, the Luftwaffe's only long range maritime fighter unit. These escorts consisted of Junkers Ju 88C-6s, which were capable of keeping up with the Do 217 F-0 and fend of intercepting RAF Coastal Command's Beaufighters and later also Mosquitos.

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

In the meantime, tests with the SG 104 progressed and several modifications were tested on different EKdo 104's Do 217 F-0s. One major upgrade was a further strengthening of the tail section, which added another 200 kg (440 lb) to the aircraft's dry weight. Furthermore, at least three aircraft were outfitted with additional dive brakes under the outer wings, so that the dive could be better controlled and intercepted. these aircraft, however, lost their plumbed underwing hardpoints, but these were only ever used for drop tanks during transfer flights - a loaded SG 104 precluded any other ordnance. On two other aircraft the SG 104 was modified to test different muzzle brakes and deflectors for the rear-facing opening, so that the gun blast was more effectively guided away from the airframe to prevent instability and structural damage. For instance, one machine was equipped with a bifurcated blast deflector that directed the rearward gasses partly sideways, away from the fuselage.

These tests did not last long, though. During the Allied Normandy landings in June 1944 E-Staffel 104 was hastily thrown into action and made several poorly-prepared attack runs against Allied support ships. The biggest success was a full hit and the resulting sinking of the Norwegian destroyer HNoMS Svenner (G03) by "1A+BA" at dawn on 6th of June, off Sword, one of the Allied landing zones. Other targets were engaged, too, but only with little effect. This involvement, however, led to the loss of three Do 217 F-0s within just two days and four more heavily damaged aircraft – leaving only two of EKdo 104's Do 217 F-0s operational.

With the Allied invasion of France and a worsening war condition, the SG 104 program was stopped in August 1944 and the idea of an airborne anti-ship gun axed in favor of more flexible guided weapons like the Hs 293 missile and the Fritz-X glide bomb. Plans for a further developed weapon with a three-round drum magazine were immediately stopped, also because there was no carrier aircraft in sight that could carry and deploy this complex 6.5 tons weapon. However, work on the SG 104 and the experience gained from EKdo 104's field tests were not in vain. The knowledge gathered from the Münchhausen program was directly used for the design of a wide range of other, smaller recoilless aircraft weapons, including the magnetically-triggered SG 113 "Förstersonde" anti-tank weapon or the lightweight SG 118 "Rohrblock" unguided air-to-air missile battery for the Heinkel He 162 "Volksjäger".

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

General characteristics:
Crew: 3 (pilot, navigator, radio operator/gunner)
Length: 20,73 m (67 ft 11 in) overall
18,93 m (62 ft 3/4 in) hull only
Wingspan: 19 m (62 ft 4 in)
Height: 4.97 m (16 ft 4 in)
Wing area: 57 m² (610 sq ft)
Empty weight: 9,065 kg (19,985 lb)
Empty equipped weight:10,950 kg (24,140 lb)
Max takeoff weight: 16,700 kg (36,817 lb)
Fuel capacity: 2,960 l (780 US gal; 650 imp gal) in fuselage tank and four wing tanks

Powerplant:
2× BMW 801D-2 14-cylinder air-cooled radial piston engines, delivering
1,300 kW (1,700 hp) each for take-off and 1,070 kW (1,440 hp) at 5,700 m (18,700 ft),
driving 3-bladed VDM constant-speed propellers

Performance:
Maximum speed: 475 km/h (295 mph, 256 kn) at sea level
560 km/h (350 mph; 300 kn) at 5,700 m (18,700 ft)
Cruise speed: 400 km/h (250 mph, 220 kn) with loaded Gerät 104 at optimum altitude
Range: 2,180 km (1,350 mi, 1,180 nmi) with maximum internal fuel
Ferry range: 2,500 km (1,600 mi, 1,300 nmi); unarmed, with auxiliary fuel tanks
Service ceiling: 7,370 m (24,180 ft) with loaded Gerät 104,
9,500 m (31,200 ft) after firing
Rate of climb: 3.5 m/s (690 ft/min)
Time to altitude: 1,000 m (3,300 ft) in 4 minutes 10 seconds
2,000 m (6,600 ft) in 8 minutes 20 seconds
6,100 m (20,000 ft) in 24 minutes 40 seconds

Armament:
1x 355.6 mm (14-inch) Sondergerät 104 recoilless gun with a single round in ventral position
1x 15 mm (0.787 in) MG 151 machine cannon with 200 rounds, fixed in the nose
1x 13 mm (0.512 in) MG 131 machine gun with 500 rounds, movable in dorsal position
Two underwing hardpoints for a 900 l drop tank each, but only used during unarmed ferry flights

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

1:72 Dornier Do 217 F-0; aircraft "1A+BA" of the Deutsche Luftwaffe, Erprobungskommando (EKdo) 104 "Münchhausen" (assigned to KG 40 1. Gruppe beim Stab ); Bordeaux/Merignac (Western France), summer 1944 (What-if/kitbashing) by Dizzyfugu, on Flickr

Well, what started as a combination of two kits of the same kind with a simple huge pipe underneath turned out to be more demanding than expected. The (incomplete) replacement engines were quite a challenge, and body work on the hull (tail stinger, fairing for the SG 104 as well as the weapon itself) turned out to be more complex and extensive than initially thought of. The result looks quite convincing, also supported by the rather simple paint scheme which IMHO just "looks right" and very convincing. And the whole thing is probably the most direct representation of the inspiring "Gunship" theme!

Pellson · December 29, 2021, 07:51:35 AM

As you say, Thomas, it does really look right! Good stuff!

Snowtrooper · December 29, 2021, 08:11:09 AM

Well, this thing certainly makes P.1500 "Monster" and Triebflügel look reasonable in comparison. Excellent work integrating the gun tube into the plane, it looks very natural now despite its size. (Still, one would have to question the sanity of a crew volunteering to pilot such a contraption...)

TomZ · December 29, 2021, 08:51:18 AM

Wow!
This looks great!!

TomZ

PR19_Kit · December 29, 2021, 10:20:46 AM

I LOVE it, and the backstory is brilliant too.

loupgarou · December 29, 2021, 10:34:18 AM

Beautiful build!
And one of the longest backstory (and complete photo coverage) you produced.
I have to say that it looks quite obscene, such an enormous frontal "protusion"....

Aren't you afraid of problems with some moral/religious group?

frank2056 · December 29, 2021, 11:09:03 AM

Beautiful build and outstanding weathering!

I wonder how long it'll be before someone "borrows" your images to "prove" that this was a real WWII German design...