Versatile bomber, nightfighter, recce-plane which also
carried the first guided aerial weapon.
The Dornier 217 was the first new German reconnaissance
bomber to enter large‑scale service with the Luftwaffe after the beginning of World War II. It began its
operational life during the last months of 1940 flying clandestine
reconnaissance missions deep into Russia‑with which Germany was, at that time,
ostensibly still on friendly terms. During 1942 and 1943 the Do 217 inflicted
most of the damage caused by German air attacks on Britain. At the same time, a
few of these aircraft operated as night fighters against the RAF night attacks
on the Reich.
In the summer of 1943‑as the performance of the Dornier was
beginning to fall short of what was required by frontline units‑the type
underwent a new lease of life. It was modified to carry radio‑guided missiles.
These were the first such weapons ever launched operationally from aircraft. In
its new role the Do 217 scored some spectacular early successes. Finally,
however, the overwhelming Allied fighter superiority on all fronts caught up
with the bomber units operating the Do 217. From the beginning of 1944 almost
all attempts to operate these aircraft against worthwhile Allied targets‑by day
or by night, with or without missiles‑resulted in the same debilitating losses.
By late summer 1944, after 1,887 examples had been delivered, the Do 217 had
been all but discarded from front‑line service in the Luftwaffe.
A twin‑engined high‑winged monoplane with twin fins and rudders, the Dornier 217 was of conventional all‑metal construction. It carried a crew of four‑pilot, observer, radio operator/air gunner and ventral gunner. The observer, as well as navigating the aircraft, was responsible for bomb aiming and firing the nose‑mounted flexible gun on the rare occasions it was used. The positioning of the crew close together in the nose made for efficiency. During operations, a lot of information could be conveyed by signs or by pointing. This minimized the distractions caused by ‘intercom natter’.
The most used
variant of the Do 217 was the E model. The forward‑firing gun armament usually
fitted was a fixed 15mm cannon and a flexible 20mm cannon. The former was fired
by the pilot and the latter by the observer. For defense there was a 13 mm
machine‑gun in the power‑operated dorsal turret, four rifle‑calibre machine‑guns
firing from the side windows of the crew compartment. Another of these weapons
(later replaced by a 13mm gun) was mounted in the ventral position. Four 500kg
bombs, or four containers each with 140 1‑kg incendiary bombs, or two 1,000kg
sea mines were the typical loads carried in the bomb bay. There was also
provision for the plane to carry a single F5B torpedo internally. But it seems
that the aircraft never carried this weapon operationally.
Like other German
bombers, the crew positions in the Do 217 were well protected with armor. The
pilot had an 8.5mm‑thick steel plate shield behind his seat, 5mm‑thick steel
under his seat pan and a further 5mm‑thick plate above and behind his head.
Behind the crew compartment was a semi‑circular transverse armored bulkhead
8.5mm thick, with 5mm plates at the sides. As was normal German practice, the
compartment for the inflatable life raft in the rear fuselage was protected
with 5mm plate at the sides, top and bottom, and 8.5mm plate at the rear.
Also, as was usual
for German bombers, self‑sealing fuel and oil tanks were fitted in the Do 217.
This was a vital safeguard. The ignition of petrol or oil leaking from tanks
caused major aircraft losses during World War II. The standard German self‑sealing
tank comprised an inner shell of compressed cellulose fibre around which was a
layer of thick leather, a layer of thick crude rubber, two layers of thin
rubber sheet and an outer layer of thick vulcanized rubber. Altogether, the
wall of the tank with its self‑sealing layer was about half‑an‑inch thick. When
bullets or shell fragments hit the tank they usually punched their way clean
through the walls and out the other side. But when the petrol or oil leaked out
of the holes and reached the crude rubber a chemical reaction was set up. This
caused the crude rubber to swell‑sealing the holes. During the sealing process
a small amount of crude rubber was dissolved into the petrol. This caused some
contamination, but not enough to seriously affect the engines. They continued
to function with little loss of efficiency.
A further factor
which helped reduce the vulnerability of the Do 217 was the fitting of air‑cooled
engines. Because there was no coolant to leak away, air‑cooled engines were
about half as likely to be stopped by battle damage as were liquid‑cooled
engines. The 1,580hp BMW 801 14‑cylinder radials of the Do 217E employed direct
fuel injection‑a useful feature because the engines continued to operate under
negative‑G conditions. This was in contrast to the float‑type carburetors
fitted to British fighters during the early war period. These cut out when
their pilots tried to follow German aircraft bunting over into a dive.
Pilots who flew the Do
217 recall that it was a stable machine with good handling characteristics at
the medium and high-speed ends of its performance range. Due to its high wing
loading, however, the landing speed was also high. And the undercarriage
frequently proved unable to take the demands made on it during a heavy landing.
With a maximum all‑up
weight of about 17 tons, a range of 1,430 miles and a top speed of 320mph, the
Dornier 217E’s closest equivalent was the American B26 Marauder. This had a
similar weight and performance and was also designed with a high wing loading.
The Dornier 217 was designed as a replacement for theearlier
Do17 medium bomber. The new plane was to have a higher performance and be able
to carry a heavier bomb load, and it had to be stressed and equipped for
dive-bombing attacks. The first prototype of the Do 217 made its maiden flight
in August 1938. But its handling characteristics were bad and the prototype
crashed the following month, killing both members of the test crew. By early in
1939 three more prototypes were flying. The problem of improving the basic
handling characteristics of the Do 217 proved relatively simple to overcome.
But that of making such a large aircraft into an effective dive-bomber proved
beyond solution. Following lengthy trials with different types of air brake,
during which some aircraft were lost and others overstressed during the pull‑out
maneuver the dive-bombing attack was deleted from the aircraft’s repertoire.
The first Do 217 to enter service with the Luftwaffe was the E variant. Late in 1940, 10 of the first production aircraft were issued to the Second Staffel of Fernaufklaerungsgruppe 11‑a long‑range reconnaissance unit which soon afterwards became involved in the clandestine high‑altitude flights over Russia. During these missions the Dorniers carried two vertically‑mounted long‑focal‑length cameras. They took the photographs of the Soviet defenses which were to play an important role when the Germans invaded Russia in June 1941.
The first bomber unit to receive the Do 217 was the Second Gruppe of Kampfgeschwader 40, based in France, which received its complement (a Gruppe had a nominal strength of 30 aircraft) during the spring and summer of 1941. At first the aircraft were employed on minelaying missions against British harbors and shipping lanes and, less often, in direct attacks on shipping. Later in 1941 the three Gruppen of Kampfgeschwader 2 moved to France, also equipped with the new bomber.
HITLER’S DEMAND
FOR RETALIATION
By this time, large‑scale German air attacks on Britain had come to a halt with the transfer of the bulk of the bomber force to the Eastern front. Do 217s concentrated on anti‑shipping work. However, this quiescent period came to an abrupt halt following the powerful RAF attack which destroyed much of Lübeck on 28 March. Hitler demanded retaliation and in the month that followed German bombers, for the most part Do 217s of KG2, launched two sharp attacks on Exeter and two more on Bath. On the very night that Bath was under attack, however, the RAF was engaged in a series of four destructive raids on the German town of Rostock. Hitler was apoplectic at this affront and in an impassioned speech he spoke of taking a copy of Baedeker’s guidebook and marking off each British city as it was razed to the ground. Because of this the series of attacks became known in Britain as the Baedeker Raids. During the late spring of 1942, Bath, Norwich, York, Cowes, Hull and Poole, Grimsby and Exeter, all suffered varying degrees of damage. But the German bombers had to penetrate the increasingly powerful British night fighter and gun defenses, and suffered heavy losses. The series of attacks ended with three raids on Birmingham and one on Hull at the end of July, which cost the Luftwaffe 27 aircraft and caused only minor damage.
Following this
battering Kampfgeschwader 2, which
was now the only bomber unit operational with the Do 217, was withdrawn from
operations over Britain to make good the losses suffered. But the respite was
to prove short lived. On 19 August Allied forces launched the large‑scale
seaborne raid on Dieppe and virtually all operational Luftwaffe units in France and Belgium went into action in defense
of the port. Operating by day, the Dorniers came up against powerful standing patrols
of Spitfires. The Germans suffered catastrophic losses. Out of a total of about
80 planes committed by KG2‑many of them flown by trainee crews‑20 were shot
down. Having started the year with an average strength of 88 trained crews, by
September 1942 KG2 was down to 23.
KG2 took little part
in operations for the rest of the year. At the end of 1942 two improved
versions of the Do 217 entered service‑the K and the M. Both of these had more
powerful engines and a redesigned low‑drag nose profile. The K model was fitted
with the new BMW 801 D radial engine developing 1,700hp, while the M employed
the similarly powerful liquid‑cooled Daimler Benz 603 in‑line. The two new
variants were about 20mph faster than the earlier E model. In addition to their
greater speed the new Dorniers had the advantage of carrying tail‑warning radar
to reduce the chances of surprise fighter attack at night, and radio altimeters
to make possible a low‑level penetration of defenses at night or in poor
visibility.
With these technical
improvements the revitalized KG2 recommenced its operations over Britain early
in 1943.
During these night
attacks the Do 217s exploited every possible stratagem to avoid the attentions
of the defenses: a low‑level approach, climbing to medium level to bomb then
letting down to low level for the withdrawal; a high-level approach, bombing
during a shallow descent and making the withdrawal. Since the bombers’ targets
were rarely more than 50 miles inland, these methods helped a lot to keep the
German losses down. Even so, the defenders were able to take their toll. During
March 1943 alone, Kampfgeschwader 2 lost
23 complete crews.
Typical of the German
raids on Britain in the summer of 1943 was that by 91 planes on Portsmouth, on
15 August. The Dornier 217s of the First and Third Gruppen of KG2 operated
from St Andre and Dreux respectively, both near Paris. After take‑off the
bombers funnelled together over Cap D’Antifer near Le Havre and headed NW
across the sea flying at an altitude of 200ft, beneath the prying beams of the
British radar. At a point 24 miles south of Brighton the bombers commenced
their climb, aiming to arrive over Portsmouth at 15,000ft. The actual attack
was delivered soon after 0100 on the morning of the 16th. It lasted about 10
minutes. Afterwards the bombers turned to port and withdrew along the route
they had come. Such a low‑level approach to a coastal target should have given
the raiders the advantage of surprise. But the RAF night‑fighters proved their
alertness by shooting down five of the attackers ‑all Do 217s. Four of the
bombers fell to the Mosquitoes of No 256 Squadron, based at Ford near Bognor,
Sussex.
The Dornier 217 was
involved in the resurgence of air activity over Britain in early 1944. But the
units operating the type represented less than a fifth of the force involved.
By that time the performance of the Do 217 was not good enough to enable it to
survive without heavy losses in the face of the powerful defenses.
NIGHTFIGHTER
During 1942 and 1943 a total of 364 J and N nightfighter versions of the Dornier 217 were
delivered to the Luftwaffe. In
addition to Lichtenstein radar
equipment with a range of 21 miles, these aircraft carried a forward‑firing
armament of four 20mm cannon and four rifle‑calibre machine‑guns. The High
Command thought that the long endurance of the Do 217 would make it a useful
addition to the German night fighter force. But it proved unpopular with the
front‑line units. It was too heavy on the controls and had too low a rate of
climb to be very effective against the RAF night bombers. After a short time
the majority of the Do 217 night fighters were relegated to training units.
About 30 were turned over to the Italian Air Force.
In the summer of 1943 some Dornier 217s were modified to carry air‑launched guided missiles‑the first such weapons ever to be used in action. There were two quite different types of missile, though subsequent accounts have frequently confused them or treated them as one.
GUIDED MISSILES
The first of the
guided missiles to enter service was the Henschel 293 glider‑bomb. This weapon
looked like a small aeroplane with a wingspan of just over 10ft. Prior to
launch it weighed a little over 2,000lb, 1,100lb of this being the warhead.
After release from the parent aircraft the rocket motor under the missile fired‑carrying
the weapon to a speed of about 370mph. Then the motor cut out and the missile
coasted on in a shallow dive, accelerating slowly towards its target. The range
of the missile depended upon the altitude of the parent plane at the time of
release. A typical operational range was five miles, for which the aircraft
needed to be at 4,500ft. In the tail of the missile was a bright tracking
flare. This allowed the observer in the parent aircraft to follow its
movements. The observer operated a small joy‑stick controller, the movement of
which fed the appropriate up‑down‑left‑right impulses to the guidance
transmitter, which in turn radiated them to the missile. Here, they were
converted into control movements for the ailerons and elevators. The observer
only had to steer the tracking flare until it appeared to be superimposed on
the target and hold it there until the missile impacted. The Henschel 293 was a
low‑speed weapon compared with a normal‑gravity bomb and as a result had little
penetrative ability. It was intended mainly for use against merchant ships and
more lightly armored warships.
The glider bombs were
used in action for the first time on 25
August 1943.Fourteen Do 217s
of the Second Gruppe of Kampfgeschwader 100 attacked a Royal
Navy U‑boat-hunting group off the NW tip of Spain. An observer on the sloop HMS
Landguard later reported, after the
aircraft had formed up off her starboard quarter at a range of about six miles
‘EXACTLY LIKE AN AIRCRAFT’
‘A pall of smoke
forming into a streamer appeared from the leading aircraft. At the time of
firing the aircraft were on a reciprocal course to the ships, well out on the
beam. The projectile was seen for some time apparently near the aircraft, but
this was probably due to the fact that it was coming towards the ship at a
constant bearing. Flashes were seen coming from the aircraft at about the time
of the firing (almost certainly this was due to the tracking flare lighting up)
but neither smoke nor flame from the projectile during the later stages of its
run . . .. The projectile then banked exactly like an aircraft and set course
towards the ship, descending at an angle of about 15° or 20°. When about two
cables from the starboard quarter the bomb appeared to be pointing straight at
the ship. Then it banked to starboard and lost height rapidly, falling in the
sea one hundred yards off Landguard’s starboard
quarter and exploding on impact.’
Two further bombs
were aimed at Landguard, both of
which exploded clear of her.
The only damage
inflicted during the action was to the sloop HMS Bideford. A near miss caused splinter damage to her port side,
holing her stores, Asdic compartment and forward mess deck and causing some
flooding. She was able to continue in action, but was later in dock for a month
being repaired.
Two days later‑27
August‑the Dorniers again attacked British warships off the NW tip of Spain.
This time the victims belonged to the 1st Escort Group comprising the
destroyers Grenville and Athabaskan, the frigates Jed and Rother and the sloop Egret. Soon after 1200 the force of 18
bombers was sighted coming in from the north. The warships were heading
southwards in a line‑abreast formation searching for U‑boats. The commander of
the force, Captain Godfrey Brewer in Egret,
immediately ordered ‘Repel Air Attack’. All ships went to action stations
and ‘ increased speed. The ships swung into two columns of two ships in line
ahead‑with two miles between columns. With her powerful AA armament of eight
4in guns, Egret was to move across the rear to support whichever column was
threatened.
The attack began with
four Dorniers flying along the ships’ port side. When they came within gun
range Athabaskan and Egret opened fire. But the bombers held
their course and each launched a glider bomb at Athabaskan. ‘ The
first three missiles fell harmlessly into the sea, but the fourth continued on
and struck and destroyed near the base of her ‘B’ gun turret. The bomb smashed
straight through the superstructure, shedding its wings and body in the
process. The warhead finally detonated just clear of the ships’ starboard side
abreast the forward end of the bridge. The explosion caused severe splinter
damage. ‘B’ turret shell‑room, two fuel tanks, the torpedomen’s mess and lower
power and gyro room were all flooded. The blast caused the fires in the boilers
to flash back into the boiler rooms. This resulted in a minor oil fire. Athabaskan’s engines stopped. She slid
to a halt.
BITTER FRUITS OF GALLANTRY
Meanwhile the German
bombers were forming up on the starboard side and Egret departed to support the column there. But her gallantry was
to bear bitter fruit. It was on her that the German crews now concentrated
their attack. Within a short time seven glider bombs were streaking towards the
sloop. The commander of Egret, Commander
John Waterhouse, reported afterwards:
Several rocket bombs were now heading for Egret and I increased to full
speed and put the wheel hard to starboard in an endeavour to point them and
present the smallest possible virtual target. Two bombs passed close astern and
a third was either hit by Oerlikon fire or else fell into the sea within thirty
feet of the starboard side amidships.
After this escape a report was received from the engine room that all
was well below and I assumed that any damage sustained was superficial. The
ship was momentarily steadied on a west‑north‑westerly course with her main
armament engaging the enemy, when two more bombs were reported approaching from
just before and just abaft the starboard beam. I did not see the one
approaching from aft, which I believe missed, but I was able to observe
carefully the behaviour of that before the beam. Swinging fast under full
starboard rudder the ship would normally have brought the bomb, which was
flying level about fifteen feet above the water, within 30° of the ship’s bow
and the bomb should have passed down the starboard side. In the event the bomb
banked sweetly and turned smoothly to starboard like a well‑piloted fighter
aircraft and so continued to head straight for the bridge . . ..
The missile struck Egret near her forecastle deck, and the
warhead continued on into the ship before detonating. The resultant explosion,
whose force was probably compounded by the detonation of one of the ship’s
magazines, almost certainly blew out a large area of plating on Egret’s port side.
She listed badly to
port. Within about 40 seconds of the explosion she had capsized completely. She
floated bottom up for over an hour before sinking. Only 36 men survived out of
a complement of 188. So it was that Egretgained thedubious distinction of being the first
ship ever to be sunk by an air‑launched guided missile.
The crew of Athabaskan were able to effect temporary
repairs to their engines and the destroyer returned to Britain under her own
steam. Permanent repair work kept her out of action for over two months.
From German records
it would seem that Leutnant Paulus
and Hauptmann Vorpahl, respectively,
had captained the Dorniers which sank Egret
and damaged Athabaskan. It must
be said, however, that the total of only two hits for an expenditure of 25
glider bombs during the attacks on 25 and 27 August was hardly impressive.
During a subsequent investigation into the causes of the missile failures‑held
at the bombers’ base at Bordeaux/Merignac‑‑it was discovered that several of
the Dorniers had had their missile control
transmitters sabotaged in a very cleverwayso thatnormal ground
tests did not reveal the fault. The SS conducted a full investigation, but the
culprit was never found.
While the Second Gruppe of Kampfgeschwader 100 was operating with its glider bombs, the Third Gruppe was preparing to go into action
with a quite different type of missile. This was the Fritz‑X guided bomb‑‑a
high‑velocity weapon designed to pierce the heaviest armor. In appearance the
Fritz‑X resembled an ordinary bomb, except that it carried four stabilizing
stub‑wings mid‑way along its body. It weighed 3,100 lb and was unpowered.
Released from altitudes around 20,000ft, it fell under gravity to reach an
impact velocity close
to that of sound. In the tail of the bomb was a tracking flare, and after
release the missile was guided down to its target in a similar way to the
glider bomb. Since the Fritz‑X had to be released from high level if it was to
reach the necessary impact velocity, III./KG 100 received the high‑flying K2
version of the Dornier 217. This model was similar to the normal K type‑except
that its wingspan was 19ft wider.
For the Third Gruppe of Kampfgeschwader 100 the big chance came on 9 September. The
Italians capitulated and their battle fleet made its dash to Malta to
surrender. The main body of the fleet sailed from La Spezia in northern Italy
and included the modern battleships Roma,
Italia and Vittorio Veneto. Early
that afternoon Major Bernhard Jope, the commander of Kampfgeschwader 100, led a striking force of eleven Dorniers off
the ground at Marseilles/Istres. Each aircraft carried a single Fritz‑X under
its starboard wing, close to the fuselage.
The bombers caught up
with the Italian warships off the Straits of Bonifacio‑between Sardinia and
Corsica. The German crews broke formation and attacked individually–aiming
their missiles at the ships twisting below. After releasing the Fritz‑X each
pilot throttled back his engines and climbed through 1,000ft. This brought the
aircraft in line with the missile and the target during the final stage of the
missile’s trajectory. It was now possible to guide the Fritz‑X on to the
target. Apart from being essential for the control of the missile, this
maneuver produced the useful bonus of throwing off predicted AA fire from
below.
One of the first
bombs scored a near miss on the Italia, temporarily
jamming her rudder. A few minutes later another scored a direct hit on Roma, on her deck near the starboard
side abeam her after funnel. The missile punched its way straight through the
ship and exploded immediately underneath the hull, wrecking her starboard steam
turbines and causing some flooding. Severely shaken, Roma’s speed fell to 16 knots and she began to list to starboard. A
little later a second bomb struck Roma. This
was almost certainly released from the Dornier flown by Oberleutnant Heinrich Schmetz with Feldwebel Oscar Huhn as observer. This missile hit the ship
squarely just in front of her bridge and pierced deep into her vitals and then
detonated. The explosion‑its effects worsened by being confined inside the
armored structure‑knocked out the remaining steam turbines and started an
uncontrollable fire which raged through to the forward magazine. With a violent
explosion the battleship snapped in two like a jack‑knife, and sank. Only 622
officers and ratings survived, out of her crew of nearly 2,000.
Shortly after the
second bomb hit Roma, Italia took a
Fritz‑X on her bow, which blew a large hole. She took on about 800 tons of
water. In spite of this, the battleship was able to limp to Malta unaided.
In the months that
followed, the Dornier 217s of Kampfgeschwader
100 scored other successes. A direct hit and two near misses with Fritz‑X
bombs on the battleship HMS Warspite put
her out of action for seven months; a single Fritz‑X hit on the cruiser HMS Uganda, which required repairs lasting
over a year. At the same time, Henschel 293 glider bombs sank the cruiser HMS Spartan and several destroyers. But the
Allies proved able to take the measure of the new threat. Strong fighter
patrols were maintained over all future concentrations of shipping. From the
spring of 1944 it was rare for the missile‑carriers to reach their targets.
They usually suffered debilitating losses whenever they tried. During the
invasion of Normandy in June 1944 the Allied shipping not only enjoyed powerful
fighter cover, but some of their number carried special transmitters which
emitted jamming on the German missile‑control frequencies blotting out the
radio command signals. As a result of these countermeasures, the missiles were
virtually useless.
The German failure to contain the Allied invasion of Normandy coincided with the success of the Allied strategic bombing offensive against the German oil industry. This led to a crippling shortage of aviation fuel. One result of this was that the Luftwaffe bomber force was reduced to a shadow of what it had been. Most of the units were disbanded, their men being sent to the fighter units or into the army. A few Dornier 217s continued in use until the end of the war; but the majority of those that survived their bomber units ended their days in aircraft parks, where they swelled the scores of strafing Allied pilots.
