Arado Ar 232

Ar 232

Arado Ar 232 B-0
Role	Transport
Manufacturer	Arado Flugzeugwerke
First flight	June 1941
Introduction	1943
Retired	1945
Primary user	Luftwaffe
Number built	~20

The Arado Ar 232 Tausendfüßler (German: "Millipede"), sometimes also called Tatzelwurm, was one of the first truly modern cargo aircraft, designed and built in small numbers by the German firm Arado Flugzeugwerke during World War II. The design introduced, or brought together, almost all of the features now considered to be "standard" in modern cargo transport aircraft designs, including a box-like fuselage slung beneath a high wing; a rear loading ramp (that had first appeared on the December 1939-flown Junkers Ju 90 V5 fifth prototype four-engined transport via its Trapoklappe); a high tail for easy access to the hold; and various features for operating from rough fields. Although the Luftwaffe was interested in replacing or supplementing its fleet of outdated Junkers Ju 52/3m transports, it had an abundance of types in production at the time and did not purchase large numbers of the Ar 232.

Design

The Ar 232 design resulted from a tender offered by the Reichsluftfahrtministerium (German Air Ministry, RLM) in late 1939 for a replacement for the Ju 52/3m transport. Both Arado and Henschel were asked for rear-loading designs powered by two 1,193 kW (1,600 hp) BMW 801A/B radial engines, which was just entering prototype production and not currently used on any front-line designs. The Arado design beat out Henschel's after an examination of the plans, and an order for three prototypes was placed in 1940.

Wilhelm van Nes led the design of the Ar 232. He began at the cargo area, with a bay directly behind the "stepless cockpit" that was 6.6 m (21 ft 7¾ in) long, 2.3 m (7 ft 6½ in) wide and 2.0 m (6 ft 6¾ in) high. Typical designs of the era would use a side-mounted door for access, but the Ar 232 used hydraulically powered clamshell-doors on the rear of the bay with a ramp to allow cargo to be rolled into the hold. The tail control surfaces were mounted on the end of a long boom to keep the area behind the doors clear so trucks could drive right up to the ramp, much like the 1944-era American Fairchild C-82 Packet of a differing twin boom fuselage configuration. The high-set tail on its "pod-and-boom" configuration fuselage allowed the Ar 232 to be loaded and unloaded faster than other designs.

For short-field performance, the Ar 232 incorporated Arado's own "travelling flap" design for the entire rear surface of the wing. Even loaded to 16,000 kg (35,270 lb), it could take-off in 200 m (656 ft). This distance could be further reduced by using rocket assist (RATO) for take-off, and either parachutes or reverse RATO for landing.

The most noticeable feature of the Ar 232 was the landing gear. Normal operations from prepared runways used a tricycle gear, but the struts could "break", or kneel, after landing to place the fuselage closer to the ground and thereby reduce the ramp angle. An additional set of ten or eleven smaller, non-retractable twinned wheels per side supported the aircraft once the main landing gear's lever-action lower oleo-strut suspended arm - carrying the main gear's wheel/tire unit - was "broken", or could be used for additional support when landing on soft or rough airfields. The aircraft was intended to be capable of taxiing at low speeds on its row of small wheels, thus being able to negotiate small obstacles such as ditches up to 1.5 m (5 ft) in width. The appearance of the row of small wheels led to the nickname "millipede". In flight, the main legs fully retracted into the engine nacelles, while the fixed support wheels remained exposed and the nose wheel only semi-retracted.

Normally operated by a crew of four, the pilot was the only member without two roles. The navigator operated a 13 mm (.51 in) MG 131 machine gun in the nose, the radio operator a 20 mm MG 151 cannon in a rotating turret on the roof, and the loadmaster a 13 mm (.51 in) MG 131 machine gun firing rearward from the extreme rear of the cargo bay above the cargo doors.

Development

Even before the prototypes were complete in 1941, the Focke-Wulf Fw 190 project had been earmarked to use the BMW 801A/B, and was proving to be a capable design. Production of the BMW 801 was insufficient to supply this new demand, and the Ar 232 was forced to use another engine. Eventually, the BMW Bramo 323 from the Junkers Ju 352 was selected instead, as it was already in production and could meet requirements if the Ar 232 really did replace the Ju 52/3m in service. The prototypes were far enough along that switching engines would have seriously delayed the program, so the first two were to be completed as the Ar 232A, and the third and a newly ordered fourth as the Ar 232B. The third and fourth prototypes (and all production aircraft) used four engines (in place of the two specified in the RLM specification) in order to provide the desired performance.

An Ar 232A-0 in 1945

The first two prototypes, bearing the Stammkennzeichen alphabetic codes GH+GN and VD+YA respectively, started trials in early 1941. The first flight resulted in the collapse of the nose gear, but the millipede wheels saved the aircraft from damage. A further ten pre-production machines were built, and were used operationally as the Ar 232A-0 while awaiting production versions. In general, the Ar 232 completely outperformed the Ju 52/3m. It carried roughly double the load over longer distances, operated from shorter runways and rougher fields if need be, and cruised about 70 km/h (44 mph) faster.

The Ar 232B program ran at the same time. With four 895 kW (1,200 hp) Bramo 323s, power increased from 2,386 kW (3,200 hp) to 3,580 kW (4,800 hp), solving the A model's problem of having little excess power in case of engine failure. This change also required the wing to be extended slightly, the span increasing just over 3 m (9 ft 10 in) in total. The extra weight of the engines also moved the center of gravity forward, which was offset by extending the cargo area rearward another meter.

Two four-engined prototypes were ordered, the V3 and V4, and V3 first flew in May 1942. A further 10 were then ordered as the Ar 232B-0, and were used widely in an operational role. However, this was the only order for the design, as the Luftwaffe gave transport aircraft production a very low priority. Many of those produced were used by Arado to transport aircraft parts between its factories, and did not see front-line service.

Plans were also made to replace the outer wing sections and control surfaces with wooden versions to conserve aluminium. Originally to be known as the Ar 232C, the design dragged on and was later renamed the Ar 432. Plans were finally put into place to start production in October 1945, but the war ended without even a prototype being produced. Two even larger planned versions, the Ar 532 and the Ar 632, would have almost doubled the wingspan to 60 m (196 ft 10 in) and added another two engines.

Two of the B-0s were captured by British forces at the end of the war. After test flights by Eric "Winkle" Brown, who gave the design excellent marks, they were used by the Royal Air Force on flights between England and Germany after the war.

Variants

Ar 232 V1 & V2: Ar 232A prototypes and research aircraft, powered by two 1,193 kW (1,600 hp) BMW 801A/B engines.

Ar 232 V3 & V4: Ar 232B prototypes and research aircraft, powered by four BMW Bramo 323R-2 Fafnir engines.

Ar 232A: Pre-production aircraft used for operational trials, powered by two BMW801 engines, only ten built.

Ar 232B: The first production aircraft powered by four Bramo 323 Fafnir engines, only ten built as Ar 232B-0.

Ar 232C: A redesigned version using wood for outer wing sections and control surfaces.

Ar 432: The planned production version of the Ar 232C, renamed.

Ar 532: Planned enlarged six-engined version of the Ar 432.

Ar 632: Planned enlarged six-engined version of the Ar 432.

Specifications (Ar 232B)

Data from

General characteristics

Crew: 4
Length: 23.52 m (77 ft 2 in)
Wingspan: 33.50 m (109 ft 10¾ in)
Height: 5.69 m (18 ft 8 in)
Wing area: 142.60 m² (1,535 ft²)
Empty weight: 12,780 kg (28,175 lb)
Max. takeoff weight: 21,150 kg (46,628 lb)
Powerplant: 4 × BMW Bramo 323R-2 Fafnir 9-cylinder radial engine, 895 kW (1,200 hp) each

Performance

Maximum speed: 308 km/h (191 mph) at 4,000 m (13,100 ft)
Cruise speed: 290 km/h (180 mph) at 2,000 m (6,560 ft)
Range: 1,062 km (660 mi)
Service ceiling: 6,900 m (22,640 ft)

Armament

Guns:
- 1 × 13 mm (.51 in) MG 131 machine gun mounted in the nose
- 1 × 20 mm MG 151 cannon mounted in an EDL 151 dorsal turret
- 1-2 × 13 mm (.51 in) MG 131 machine gun mounted in the rear position
- 8 × 7.92 mm (.312 in) MG 34 machine guns mounted in side windows when transporting infantry

References

Notes

Bibliography

Green, William. Warplanes of the Third Reich. London: Macdonald and Jane's Publishers Ltd., 1970 (fourth impression 1979). ISBN 0-356-02382-6.
Myhra, David Arado Ar 232: The Luftwaffe's Combat Zone Transport Aircraft in World War II. Atglen, PA: Schiffer Military History, 2002. ISBN 0-7643-1665-6.
Smith J.R. and Kay, Anthony L. German Aircraft of the Second World War. London: Putnam & Company Ltd., 1972. ISBN 0-370-00024-2.

External links

Media related to Arado Ar 232 at Wikimedia Commons

Aircraft produced by Arado Flugzeugwerke

Ar 64 Ar 65 Ar 66 Ar 67 Ar 68 Ar 69 Ar 76 Ar 79 Ar 80 Ar 81 Ar 95 Ar 96 Ar 195 Ar 196 Ar 197 Ar 198 Ar 199 Ar 231 Ar 232 Ar 233 Ar 234 Ar 240 Ar 296 Ar 396 Ar 432 Ar 440 Ar 532 E.340 E.377 E.380 E.381 E.500 E.530 E.555 E.560 E.561 E.580 E.581 E.583 L I L II S I SC I SC II SD I SD II SD III SSD I V I W 2

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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