Dornier Do 335

Do 335 Pfeil

The only surviving Do 335 (VG+PH) at the Steven F. Udvar-Hazy Center at Washington, D.C.'s Dulles Airport
Role	Fighter-bomber
Manufacturer	Dornier Flugzeugwerke
First flight	26 October 1943
Introduction	1944
Retired	1945
Status	Retired
Primary user	Luftwaffe
Produced	1944–1945
Number built	37^[1]

The Dornier Do 335 Pfeil ("Arrow") was a World War II heavy fighter built by the Dornier company. The two-seater trainer version was also called Ameisenbär ("anteater"). The Pfeil's performance was much better than other twin-engine designs due to its unique "push-pull" layout and the much lower aerodynamic drag of the in-line alignment of the two engines. It was Germany's fastest piston-engined aircraft of World War II.^[2] The Luftwaffe was desperate to get the design into operational use, but delays in engine deliveries meant only a handful were delivered before the war ended.

Design and development

The origins of the Do 335 trace back to World War I when Claude Dornier designed a number of flying boats featuring remotely driven propellers and later, due to problems with the drive shafts, tandem engines. Tandem engines were used on most of the multi-engine Dornier flying boats that followed, including the highly successful Do J Wal and the gigantic Do X. The remote propeller drive, intended to eliminate parasitic drag from the engine entirely, was tried in the innovative but unsuccessful Do 14, and elongated, tubular drive shafts as later used in the Do 335 saw use in the rear engines of the four-engined, twinned tandem-layout Do 26 flying boat.

There are many advantages to this design over the more traditional system of placing one engine on each wing, the most important being power from two engines with the frontal area (and thus drag) of a single-engine design, allowing for higher performance. It also keeps the weight of the twin powerplants near, or on, the aircraft centerline, increasing the roll rate compared to a traditional twin. In addition, a single engine failure does not lead to asymmetric thrust, and in normal flight there is no net torque so the plane is easy to handle. The choice of a full "four-surface" set of cruciform tail surfaces in the Do 335's rear fuselage design, included a ventral vertical fin–rudder assembly to project downwards from the extreme rear of the fuselage, in order to protect the rear propeller from an accidental ground strike on takeoff. The presence of the rear pusher propeller also mandated the provision for an ejection seat for safe escape from a damaged aircraft, and designing the rear propeller and dorsal fin mounts to use explosive bolts to jettison them before an ejection was attempted — as well as twin canopy jettison levers, one per side^[3] located to either side of the forward cockpit interior just below the sills of the five-panel windscreen's sides, to jettison the canopy from atop the cockpit before ejection.^[4]

In 1939, Dornier was busy working on the P.59 high-speed bomber project, which featured the tandem engine layout. In 1940, he commissioned a test aircraft, closely modeled on the airframe of the early versions of the Dornier Do 17 bomber but only 40% of the size of the larger bomber, with no aerodynamic bodies of any sort on the wing panels (the original Do 17 had twin engine nacelles on its wings) and fitted with a retractable tricycle landing gear to validate his concept for turning the rear pusher propeller with an engine located far away from it and using a long tubular driveshaft. This aircraft, the Göppingen Gö 9 showed no unforeseen difficulties with this arrangement, but work on the P.59 was stopped in early 1940 when Hermann Göring ordered the cancellation of all projects which would not be completed within a year or so.

In May 1942, Dornier submitted an updated version with a 1,000 kg (2,200 lb) bombload as the P.231, in response to a requirement for a single seat, Schnellbomber-like high-speed bomber/intruder. P.231 was selected as the winner after beating rival designs from Arado, Junkers, and Blohm & Voss development contract was awarded as the Do 335. In autumn 1942, Dornier was told that the Do 335 was no longer required, and instead a multi-role fighter based on the same general layout would be accepted. This delayed the prototype delivery as it was modified for the new role.

Do-335s on the apron at Oberpfaffenhofen at the war's end, including unfinished two-seat versions

The distinctive use of a nose-mount annular radiator for the forward engine (much like a Jumo 211-powered Ju 88, or Jumo 213-powered Focke-Wulf Fw 190D-9) and a ventral-fuselage mount airscooped radiator installation for cooling the rear engine (appearing like that on a P-51 Mustang), when fitted with DB 603A engines delivering 1,750 PS (1,287 kW, 1,726 hp) at takeoff — the largest displacement (at 44.52 litres) inverted V12 aircraft engine design mass-produced during the Third Reich's existence — the Do 335 V1 first prototype, bearing the Stammkennzeichen (factory radio code) of CP+UA, flew on 26 October 1943 under the control of Flugkapitän Hans Dieterle, a regular Heinkel test pilot and later primary Dornier test pilot. However, several problems during the initial flight of the Do 335 would continue to plague the aircraft through most of its short history. Issues were found with the weak landing gear and with the maingear's wheel well doors, resulting in them being removed for the remainder of the V1's test flights. The Do 335 V1 made 27 flights, flown by three different pilots. During these test flights the V2 (W.Nr 230002), Stammkennzeichen CP+UB was completed and made its first flight on 31 December 1943, again under the control of Dieterle. New to the V2 were upgraded DB 603A-2 engines, and several refinements learned from the test flights of the V1 as well as further windtunnel testing. On 20 January 1944, the Do 335 V3 (W.Nr. 230004), Stammkennzeichen CP+UC was completed and flown for its first time by Werner Altrogge. The V3 was powered by the new pre-production DB 603G-0 engines which could produce 1,900 PS (1,400 kW) at take-off and featured a slightly redesigned canopy which included twin rear-view mirrors in blisters, one in each of two matching side panels of the well-framed, eleven-panel main canopy's openable section. Following the flights of the V3, in mid January 1944, RLM ordered five more prototypes (V21–V25), to be built as night fighters. By this time more than 60 hours of flight time had been put on the Do 335 and reports showed it to be a good handling, but more importantly, very fast aircraft, described by Generalfeldmarschall Erhard Milch himself as "...holding its own in speed and altitude with the P-38 and it does not suffer from engine reliability issues". Thus the Do 335 was scheduled to begin mass construction, with the initial order of 120 preproduction aircraft to be manufactured by DWF (Dornier-Werke Friedrichshafen) to be completed no later than March 1946. This number included a number of bombers, destroyers (heavy fighters), and several yet to be developed variants. At the same time, DWM (Dornier-Werke München) was scheduled to build over 2000 Do 335s in various models, due for delivery in March 1946 as well.

On 23 May 1944, Hitler, as part of the developing Jägernotprogramm directive which took effect on 3 July, ordered maximum priority to be given to Do 335 production. The main production line was intended to be at Manzell, but a bombing raid in March destroyed the tooling and forced Dornier to set up a new line at Oberpfaffenhofen. The decision was made, along with the rapid shut-down of many other military aircraft development programs, to cancel the Heinkel He 219 night fighter, which also used the DB 603 engines, and use its production facilities for the Do 335 as well. However, Ernst Heinkel managed to delay, and eventually ignore, its implementation, continuing to produce examples of the He 219A.

At least 16 prototype Do 335s were known to have flown (V1–V12, W.Nr 230001-230012 and Muster-series prototypes M13–M17, W.Nr 230013-230017) on a number of DB603 engine subtypes including the DB 603A, A-2, G-0, E and E-1. The first preproduction Do 335 (A-0s) starting with W.Nr 240101, Stammkennzeichen VG+PG, were delivered in July 1944. Approximately 22 preproduction aircraft were thought to have been completed and flown before the end of the war, including approximately 11 A-0s converted to A-11s for training purposes. One such aircraft was transferred the Royal Aircraft Establishment in Farnborough, and later crashed onto a local school.^[5]

Flight tests

Do 335 tested in the USA, and today the only surviving example

The first 10 Do 335 A-0s were delivered for testing in May. By late 1944, the Do 335 A-1 was on the production line. This was similar to the A-0 but with the uprated DB 603 E-1 engines and two underwing hardpoints for additional bombs, drop tanks or guns. It was capable of a maximum speed of 763 km/h (474 mph) at 6,500 m (21,300 ft) with MW 50 boost, or 686 km/h (426 mph) without boost, and able to climb to 8,000 m (26,250 ft) in under 15 minutes. Even with one engine out, it could reach about 563 km/h (350 mph).

Delivery commenced in January 1945. When the United States Army overran the Oberpfaffenhofen factory in late April 1945, only 11 Do 335 A-1 single-seat fighter-bombers and two Do 335 A-12 trainers had been completed.

French ace Pierre Clostermann claimed the first Allied combat encounter with a Pfeil in April 1945. In his book The Big Show (pp. 273–274) he describes leading a flight of four Hawker Tempests from No. 3 Squadron RAF over northern Germany, when he intercepted a lone Do 335 flying at maximum speed at treetop level. Detecting the British aircraft, the German pilot reversed course to evade. Despite the Tempest's considerable low altitude speed, the Royal Air Force fighters were not able to catch up or even get into firing position.

Variants

Dornier Pfeil

Built

Do 335 A-0 : 10 pre-production aircraft.
Do 335 A-1 : Single-seat fighter-bomber aircraft.

Proposed

Do 335 A-2: single-seat fighter-bomber aircraft with new weapon aiming systems, later proposed longer wing and updated DB603L engines.
Do 335 A-3: single-seat reconnaissance aircraft built from A-1 aircraft, later proposed with longer wing.
Do 335 A-4: single-seat reconnaissance aircraft with smaller cameras than the A-3
Do 335 A-5: single-seat night fighter aircraft, later night and bad weather fighter with enlarged wing and DB603L engines.
Do 335 A-6: two-seat night fighter aircraft, with completely separate second cockpit located above and behind the original.
Do 335 A-7: A-6 with longer wing.
Do 335 A-8: A-4 fitted with longer wing.
Do 335 A-9: A-4 fitted with longer wing, DB603L engines and pressurized cockpit.
Do 335 B-1: abandoned in development.
Do 335 B-2: single-seat destroyer aircraft. Fitted with 2 additional MK 103 in the wings and two 300 litre (80 US gal) drop tanks.
Do 335 B-3: updated B-1 but with longer wing.
Do 335 B-4: update of the B-1 with longer wing, DB603L engine.
Do 335 B-6: night fighter.
Do 335 B-12: dual-seat trainer version for the B-series aircraft.
Do 435: a Do 335 with the redesigned, longer wing. Allied intelligence reports from early May 1945 make a report of a spotted Do 435 at the Dornier factory airfield at Lowenthal.
Do 535: actually the He 535, once the Dornier P254 design was handed over to Heinkel in October 1944; fitted with jet engine in place of rear piston engine^[6]
Do 635: long-range reconnaissance version. Also called Junkers Ju 635 or Do 335Z. Mock up only.
Do P 256: turbojet nightfighter version, with two podded HeS 011 turbojet engines,^[7] based on Do 335 airframe.

Survivor

Only one Do 335 survives, the second preproduction Do 335 A-0, designated A-02, with construction number (Werknummer) 240 102, and factory radio code registration, or Stammkennzeichen, of VG+PH. The aircraft was assembled at the Dornier plant in Oberpfaffenhofen, Bavaria on 16 April 1945. It was captured by Allied forces at the plant on 22 April 1945. VG+PH was one of two Do 335s to be shipped to the United States aboard the Royal Navy escort carrier HMS Reaper, along with other captured German aircraft, to be used for testing and evaluation under a USAAF program called "Operation Lusty". One Do 335 (registration FE-1012) went to the USAAF and was tested in early 1946 at Freeman Field, Indiana. Its fate is not recorded.

VG+PH went to the Navy for evaluation and was sent to the Test and Evaluation Center, Patuxent River Naval Air Station, Maryland. Following testing from 1945 to 1948, the aircraft languished in outside storage at Naval Air Station Norfolk. In 1961, it was donated to the Smithsonian's National Air Museum, though it remained in deteriorating condition at Norfolk for several more years before being moved to the National Air and Space Museum's storage facility in Suitland, Maryland. In October 1974, VG+PH was returned to the Dornier plant in Oberpfaffenhofen, Germany (then building the Alpha Jet) for a complete restoration. In 1975, the aircraft was restored by Dornier employees, many of whom had worked on the airplane originally. They were amazed that the aforementioned explosive charges built into the aircraft to blow off the dorsal fin and rear propeller prior to pilot ejection were still installed and active 30 years later.

Following restoration the completed Do 335 was displayed at the Hanover, Germany Airshow from 1 May to 9 May 1976. After the air show, the aircraft was loaned to the Deutsches Museum in Munich where it was on display until 1986, when it was shipped back to Silver Hill, Maryland. VG+PH can be seen today in the Steven F. Udvar-Hazy Center of the National Air and Space Museum alongside other unique late-war German aircraft such as the only known example of the Arado Ar 234 B-2 Blitz jet reconnaissance-bomber, and the fully restored fuselage and tail surfaces of the only complete surviving Heinkel He 219A Uhu (Eagle-Owl) night fighter (the wings and engines/nacelles are still undergoing restoration).

Specifications (Do 335 A-1)

Data from ^[8]

General characteristics

Crew: 1, pilot
Length: 13.85 m (45 ft 5 in)
Wingspan: 13.8 m (45 ft 1 in)
Height: 4.55 m (15 ft)
Wing area: 38.5 m² (414 ft²)
Empty weight: 7,400 kg (16,314 lb)
Max. takeoff weight: 9,600 kg (21,164 lb)
Powerplant: 2 × Daimler-Benz DB 603A 12-cylinder inverted engines, 1,750 PS (1,287 kW, 1,726 hp) each

Performance

Maximum speed: 765 km/h (474 mph)
Service ceiling: 11,400 m (37,400 ft)

Armament

1 × 30 mm (1.18 in) MK 103 cannon (as forward engine-mounted Motorkanone)
2 × 20 mm MG 151/20 cowl-mount, synchronized autocannons
Up to 1,000 kg (2,200 lb) bombload

References

Notes

↑ Wilson 1998, p. 56.
↑ Smith, J. Richard. Dornier Do 335: The Luftwaffe's Fastest Piston-Engine Fighter (Classic Publications, 2007).
↑
↑ "Century of Flight - German Aircraft of World War Two - Dornier Do 335 Pfeil". www.century-of-flight.net. Century of Flight.
↑ Smith, Joshua. "Farnborough Air Sciences Trust Museum uncovers secrets behind a plane which crashed on Cove school". GetHampshire. Aldershot News & Mail Series,. Retrieved 1 February 2016.
↑ Christopher, John. The Race for Hitler's X-Planes (The Mill, Gloucestershire: History Press, 2013), p.179.
↑ Schick, Walter; Meyer, Ingolf (1997), Luftwaffe Secret Projects: Fighters, 1939–45, Leicester: Midland, p. 123 .
↑ http://www.century-of-flight.net/Aviation%20history/photo_albums/timeline/ww2/Dornier%20Do%20335%20Pfeil.htm

Bibliography

Angelucci, Enzo. The Rand McNally Encyclopedia of Military Aircraft, 1914–1980. San Diego, California: The Military Press, 1983. ISBN 0-517-41021-4.
Wilson, Stewart. Aircraft of WWII. Fyshwick, ACT, Australia: Aerospace Publications Pty Ltd., 1998. ISBN 1-875671-35-8.

External links

Wikimedia Commons has media related to Dornier Do 335.

Dornier and Zeppelin-Lindau aircraft

Zeppelin-Lindau 1914-1919	Rs.I Rs.II Rs.III Rs.IV C.I C.II CS.I CL.II D.I V1

Dornier designations 1919-1933	Do A Do B Do C Do D Do E Do F Do G Do H Do J Do K Do L Do N Do O Do P Do Q Do R Do S Do T Do U Do V Do X Do Y Delphin Komet Libelle Merkur Spatz Wal

RLM designations 1933-1945	Do 10 Do 11 Do 12 Do 13 Do 14 Do 15 Do 16 Do 17 Do 18 Do 19 Do 20 Do 22 Do 23 Do 24 Do 25 Do 26 Do 29 Do 212 Do 214 Do 215 Do 216 Do 217 Do 317 Do 318 Do 335 Do 417 Do 435 Do 635 P.59 P.85 P.174 P.184 P.192 P.231 P.232 P.238 P.247 P.252 P.254 P.256 P.273 P.1075

Dornier designations post-1945	Do 24 Do 25 Do 27 Do 28 Do 29 Do 31 Do 32 Do 34 Do 128 Do 132 Do 228 Do 231 328 328JET 428 528 728JET 928JET Aerodyne Alpha Jet Projekt 621 Seastar S-Ray 007

See also Claudius Dornier and Dornier Museum Friedrichshafen

Reich Air Ministry aircraft designations

1 to 100	B 9 Gö 9 Do 10 Do 11 Wn 11 Do 12 Do 13 Do 14 Do 15 Wn 15 Do 16 Wn 16 Do 17 Do 18 Do 19 Do 20 Do 22 Do 23 Do 24 Kl 25 Do 26 Kl 26 M 27 Do 29 Kl 31 Kl 32 W 33 L 33 W 34 Kl 35 Kl 36 HD 37 HD 38 G 38 DFS 39 BV 40 DFS 40 A 40 Fw 42 He 42 Fw 43 HD 43 Fw 44 He 45 He 46 Ju 46 Fw 47 Ju 47 K 47 A 48 He 49 Ju 49 He 50 A 50 He 51 K 51 Ju 52 K 53 NR 54 Fw 55 NR 55 Fw 56 Fw 57 Fw 58 He 58 He 59 He 60 Ju 60 Fw 61 He 61 Fw 62 He 62 He 63 Ar 64 He 64 Ar 65 He 65 Ar 66 He 66 Ar 67 Ar 68 Ar 69 He 70 He 71 He 72 He 74 Ar 76 Ar 77 Ar 79 Ar 80 Ar 81 Ju 85 Ju 86 Ju 87 Ju 88 Ju 89 Ju 90 Ar 95 Ar 96 Fi 97 Fi 98 Fi 99 He 100

101 to 200	Al 101 Al 102 Al 103 Fi 103 Fh 104 Kl 105 Kl 106 Kl 107 Bf 108 Bf 109 Bf 110 He 111 He 112 He 113 He 114 He 115 He 116 Hs 117 He 118 He 119 He 120 Hs 121 Hs 122 Hs 123 Hs 124 Hs 125 Hs 126 Hs 127 Hs 128 Hs 129 Hs 130 Bü 131 Hs 132 Bü 133 Bü 134 Ha 135 Ha 136 Hü 136 Ha 137 BV 138 Ha 139 Ha 140 BV 141 BV 142 BV 143 BV 144 Go 145 Go 146 Go 147 Ju 147 Go 149 Go 150 Kl 151 Ta 152 Kl 152 Ta 153 Ta 154 BV 155 Fi 156 Fi 157 Fi 158 Fw 159 Ju 160 Bf 161 He 162 Bf 162 Bf 163 Me 163 Me 164 Fi 166 FK 166 Fi 167 Fi 168 He 170 He 172 He 176 He 177 He 178 Bü 180 Bü 181 Bü 182 Ta 183 Fl 184 Fl 185 Fw 186 Ju 186 Fw 187 Ju 187 Ju 188 Fw 189 Fw 190 Fw 191 Ao 192 DFS 193 DFS 194 Ar 195 Ar 196 Ar 197 Ar 198 Ar 199 Fw 200

201 to 300	Si 201 Si 202 DFS 203 Si 204 Fw 206 Me 208 Me 209 Me 209 (1943) Me 210 Hü 211 Do 212 Do 214 Do 215 Do 216 Do 217 Hs 217 He 219 He 220 BV 222 Fa 223 Fa 224 Ao 225 Fa 225 BV 226 Ho 226 FGP 227 DFS 228 Ho 229 DFS 230 Ar 231 Ar 232 Ar 233 Ar 234 Do 235 BV 237 BV 238 Fw 238 Ar 239 Ar 240 Go 241 Go 242 Go 244 BV 246 Ju 248 BV 250 Fw 250 Ho 250 Ho 251 Ho 252 Ju 252 Fi 253 Ho 253 Ta 254 Ho 254 Fi 256 Sk 257 Fw 261 Me 261 Me 262 Me 263 Me 264 Fl 265 Me 265 Fa 266 Ho 267 Ju 268 Fa 269 He 270 We 271 Fw 272 He 274 He 275 He 277 He 278 He 280 Fl 282 Fa 283 Ta 283 Fa 284 Fl 285 Ju 286 Ju 287 Ju 288 Ju 290 Me 290 As 292 Hs 293 Hs 294 Hs 295 Ar 296 Hs 296 Hs 297 Hs 298 Fw 300

301-	Me 309 Me 310 Do 317 Do 318 He 319 Me 321 Ju 322 Me 323 Me 328 Me 329 Fa 330 DFS 331 DFS 332 Fi 333 Me 334 Do 335 Fa 336 Fl 339 E.340 WNF 342 He 343 Rk 344 So 344 Go 345 DFS 346 Rk 347 Ba 349 Ju 352 Me 362 Me 364 Ju 388 Ju 390 Fw 391 Ar 396 Ta 400 Me 409 Me 410 Do 417 He 419 ZMe 423 Ar 430 Ka 430 Ar 432 Do 435 Ar 440 Ju 452 Me 462 Ju 488 Fw 491 Me 509 Me 510 He 519 ZSO 523 Ar 532 Do 535 E.555 Me 609 Ar 632 Do 635

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