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TRATTORI PER IL FRONTE ORIENTALE
Radschlepper Ost Skoda

by Paolo Tavano

ITALIANO FRANCAIS ENGLISH

ITALIANO

I vari veicoli tattici militari, ruotati e cingolati, che il governo e l'industria tedeschi progettarono e produssero durante gli Anni 30 furono la crema dell'ingegneria automobilistica contemporanea. Per i metodi di rilevamento, le tattiche di guerra lampo ed una veloce vittoria, gli elaborati e sofisticati veicoli a motore utilizzati dalle "divisioni d'élite" della Wehrmacht al momento dell'invasione dei Paesi confinanti nel 1938-40 erano ideali. Inoltre, essi debuttarono estremamente bene nelle parate, nei film di propaganda e così via, ma si dimostrarono molto meno affidabili per la realtà del fronte orientale quando i combattimenti si trascinavano e si impantanarono durante l'inverno 1941-42. Il durissimo lavoro a rigidissime temperature sottozero, combinato con problemi di manutenzione, pretese il suo pedaggio; ulteriori difficoltà derivarono dalla cronica carenza di veicoli a motore, sia sul fronte orientale che altrove. In particolare, i trattori d'artiglieria divennero scarsi, in parte per la grande quantità di materie prime richieste, per non menzionare le ore di manodopera necessarie per la loro elaborata costruzione; i rifornimenti non potevano stare al passo con la richiesta. C'era anche un'acuta carenza di cavalli per gli equipaggiamenti ippotrainati nell'ambito delle unità di fanteria. La carenza nei trasporti fu risolta in una certa misura mettendo in servizio equipaggiamenti catturati al nemico, benché ciò, d'altronde, si andò a sommare ai problemi di manutenzione e riparazione esistenti. Inoltre, pochi veicoli furono in grado di far fronte adeguatamente alle atroci condizioni ed alle severe temperature incontrate in Russia. Sia la durata del conflitto che le enormi distanze in territorio nemico furono grossolanamente sottovalutati e questi errori di calcolo furono pagati a caro prezzo. Fu il generale von Schell che tentò di riorganizzare la produzione di veicoli non corazzati in Germania; il suo "Schell Programm" ridusse l'ampia produzione totale di modelli per categoria - dalle motociclette agli autocarri - ad un minimo accettabile, abbandonando i tipi meno affidabili e concentrando la produzione di massa su quelli migliori. Esempi tipici di questo schema semplificativo furono la Volkswagen "Kübelwagen", la gamma Steyr 1500(A) da 1,5 ton e gli autocarri Opel Blitz da 3 ton. Ma fu Hitler in persona, nel novembre 1941, ad affermare che non vi era motivo di tenere in produzione costosissimi trattori d'artiglieria semicingolati che in teoria sarebbero durati 120 anni quando chiunque sapeva che difficilmente potevano sopravvivere a più di due anni di vita reale in combattimento. Egli decretò che si sarebbe dovuto progettare e mettere in produzione una nuova generazione di trattori molto semplificati; sofisticazioni e dettagli superflui si dovevano abbandonare immediatamente, soltanto per preservare materiali di prima qualità - davvero un punto molto valido! In modo particolare per il fronte orientale, lo Heereswaffenamt Wa.Prüf 6 (l'appropriato Dipartimento del Ministero) prese accordi con la Steyr-Daimler-Puch AG nell'annessa Austria per la progettazione e la costruzione di due nuovi tipi di trattore d'artiglieria: il Radschlepper Ost (trattore ruotato, est) ed il Raupenschlepper Ost (trattore cingolato, est). Per la prima richiesta, i produttori se ne spuntarono, nel gennaio 1942, con una modifica piuttosto sgraziata dell'autocarro standardizzato Steyr 1500(A) da 1,5 ton 4x4; esso era caratterizzato da assi rigidi con ruote a raggi, interamente in acciaio, con un diametro di 1,5 m. Il trattore cingolato da essi progettato era il famosissimo RSO/01 che, a differenza di quello ruotato, presto entrò in produzione di serie nei propri stabilimenti così come in quelli Auto Union/Wanderer, Gräf & Stift e KHD/Magirus (RSO/03). In aggiunta al modello standard, vi fu una moltitudine di derivati, molti dei quali rimasti allo stadio sperimentale; del 4x4 a grandi ruote non si ebbero più notizie. Per il progetto di trattore ruotato, lo HWA (Heereswaffenamt) iniziò trattative con la Dr.-Ing. h.c. F. Porsche KG di Stuttgart-Zuffenhausen, la notissima società automobilistica, per una proposta alternativa. Ferdinand Porsche (1875 - 1951) era un genio e artefice di un'ampia gamma di progetti automobilistici che andavano dalla piccola KdF "vettura del popolo" (Volkswagen, comprese "Kübel" e l'anfibia "Schwimmer") ai carri armati. Nell'aprile del 1942, Hitler aveva reso noto che come requisito per il nuovo trattore egli voleva un veicolo alto a quattro ruote, a bassa velocità ma al tempo stesso potente e semplice, non diverso dalla Zugmaschinen austriaca della I Guerra Mondiale e Porsche fu la scelta ovvia, poiché egli era stato ampiamente artefice di macchine del tipo Austro-Daimler M12 e M16 di quel periodo. Negli uffici Porsche l'ordine dell'HWA fu eseguito sotto il contratto n° 175 (diventando Typ 175) e gli stabilimenti Skoda di Plzen (Pilsen), Cecoslovacchia, furono incaricati della realizzazione dei prototipi. Anche in questo caso, c'è un altro parallelo con i trattori della I Guerra Mondiale: benché portassero il nome Austro-Daimler, questi in effetti erano stati costruiti da Skoda che, all'epoca, era associata alla ditta austriaca; anche molti dei pezzi d'artiglieria da essi trainati erano di fabbricazione Skoda. Nel frattempo, poiché il tempo stringeva (Hitler voleva la fornitura dei trattori alle truppe per l'imminente inverno 1942-43), fu studiata un'ulteriore soluzione alternativa. La Latil di Suresnes, Seine, nella Francia occupata ed ora operante per la Wehrmacht sotto il controllo e la supervisione della Daimler-Benz AG, per molti anni aveva fornito alle truppe francesi trattori pesanti d'artiglieria a 4 ruote motrici; noti come tipo TAR, essi furono utilizzati in gran numero durante la Grande Guerra ed in seguito sviluppati negli Anni 20 e 30 (TAR3, 4, 5, TARH1, 2). Molti trattori TAR furono catturati dalla Wehrmacht nel 1939-40 e furono giudicati di qualità eccellente; furno anche impiegati dai tedeschi, come Latil Schw. Radschlepper (f). Lo HWA, nel 1942, ordinò alla Latil di modificare il loro progetto TARH per venire incontro alle richieste di Hitler, facendo uso di grandi ruote metalliche, non impiegando gomma e approntandolo per la produzione di massa, richiedendone 1000 prima della fine dell'anno ed in seguito una cadenza mensile di 1000 unità prodotte. Le ruote grandi erano una caratteristica in cui Hitler credeva molto; egli probabilmente ricordava le prestazioni degli Austro-Daimler durante il conflitto 1915-18 quando gli austriaci - suoi compatrioti - ne utilizzarono una quantità relativamente grande ed anche il Kaiser ne prese in prestito alcuni, completi di mortaio Skoda da 30,5 cm, durante l'assedio dei forti belgi. A differenza di Porsche, Hitler li riteneva adatti per le disgraziate "strade" della Russia, che erano poco più di larghe piste di fango denso, nel quale le sue ipotetiche armate mobili affondavano. Ma quanto si sbagliava! I prototipi dell'Ostradschlepper furono testati e mentre si comportarono ragionevolmente bene su certi tipi di terreno, si dimostrarono pressoché inutili nella neve, particolarmente su superfici ghiacciate e neve dura su strade inghiaiate. Porsche, che era stato in Russia e ne conosceva le condizioni, si era formato la propria opinione ma, abbastanza stranamente, Hitler e compagni non gliela chiesero mai; a Porsche fu chiesto di progettare l'RSO, usando la minor quantità possibile delle scarse materie prime disponibili (niente rame, niente gomma per gli pneumatici) e lo realizzò compiacentemente, senza domande. I massimi impiegati civili del Reich avevano un proprio modo di lavorare, coinvolti in contese ed interessi finanziari, e Porsche sapeva che era più saggio non interferire con essi e le loro politiche. Una conseguenza di questo sistema fu che progetti come quelli dell'RSO tendevano a trascinarsi, senza un'adatta supervisione,, prendendo troppo tempo, per finire in un fallimento. Porsche aveva lavorato duramente ed il primo prototipo di RSO fu pronto per le prove il 1° ottobre 1942, appena sette mesi dopo che l'ordine iniziale era stato dato. A fine ottobre, i veicoli furono messi alla prova presso le installazioni dell'esercito a Berka, presso Eisenach, ed il 20 novembre il Ministro per la Produzione Bellica Albert Speer presenziò ad una dimostrazione. Hitler stesso fu il primo spettatore delle prestazioni dello Skoda e del Latil il 4 gennaio 1943, nelle vicinanze del suo quartier generale nella Prussia orientale. Egli non rimase impressionato e, come risultato, decretò che l'ordinativo di produzione di 200 unità della cosiddetta Serie O già assegnato alla Skoda (cioè AG Vorm. Skodawerke, così era chiamata durante la guerra), fosse dimezzato. Durante questi mesi di prove furono apportate numerose migliorie. Il consumo era di 2 litri di benzina per chilometro, forse non eccessivo per questo tipo di macchina (e del 10% minore di quello del Latil), ma la benzina era estremamente scarsa e, quando Porsche chiese all'HWA altri 4000 litri di carburante per il proseguimento delle prove, gli fu risposto per iscritto che la richiesta sarebbe stata presa in considerazione. L'HWA era chiaramente scontenta dell'RSO e nell'agosto del 1943 dichiarò che non sarebbe stato fornito altro carburante e che l'RSO era storia morta; Porsche non ne fu contento. A differenza di Hitler, egli non aveva mai creduto che un veicolo come il Radschlepper Ost fosse la soluzione del problema originale, ma l'aveva progettato perché lui era un progettista, non un politico, e gli era stato chiesto di progettarlo. Egli calcolò che vi fossero abbastanza impiegati civili ed ufficiali di alto rango per decidere se una richiesta era valida o no e sino a che limite. Sebbene non si fosse interamente abbandonato alle discussioni, Porsche capì che era stato silurato da Hitler il quale, in qualità di Führer, aveva l'autorità di dominare sia l'HWA che il ministero di Speer; ciò era sovente necessario allo scopo di ottenere dei risultati, ma solitamente portava a conflitti interdipartimentali. Così, agli inizi del 1943, l'ordine iniziale per gli RSO fu ridotto e alla fine di quello stesso anno il progetto fu terminato definitivamente. Il tempo era trascorso e la richiesta di un trattore speciale per il fronte russo non era andata avanti... L'Autore dell'articolo originale ricorda vivamente che nell'inverno del 1944-45 una colonna di almeno una dozzina di Skoda RSO arrivò nella sua città natale nell'Olanda occupata; essi erano dipinti con la tonalità standard Einheits di giallo sabbia ed avevano un aspetto abbastanza impressionante. Dodici anni e tutto occhi ed orecchi, gli fu detto da uno degli autisti che i veicoli dovevano essere usati (come un'arma nuova e segreta) unitamente a grossi aratri, per distruggere i binari spezzando le traversine come fiammiferi: ciò suonava barbaro e fantastico allo stesso tempo. Dopo un attimo, questi Skoda, estremamente rari soltanto perché erano nuovi di zecca, furono condotti in una carrozzeria appena fuori città per essere mimetizzati, due alla volta. Lungo la strada verso l'officina (dove l'Autore ebbe l'opportunità di salire a bordo di uno di essi e studiarlo in dettaglio) c'era un passaggio a livello il cui approccio era leggermente in pendenza. Era dicembre o gennaio, le strade erano ghiacciate e stava nevicando; ora, a causa della cronica carenza di carburante della Wehrmacht, era una regola, se non un ordine, per un veicolo a benzina (scarico) prenderne a rimorchio un altro (talvolta più di uno) e lo Skoda RSO non fece eccezioni. In quel caso due di essi stavano lottando per attraversare il passaggio a livello; le ruote d'acciaio dell'unità trainante iniziarono a perdere aderenza, quando le barriere furono abbassate per il passaggio di un treno e perciò i veicoli si arrestarono. Passato il treno, il primo Skoda tentò di muoversi nuovamente ma le gigantesche ruote slittavano, anche se a velocità piuttosto bassa; fu avviato il secondo veicolo - cosa che richiese una discreta dose di sforzo e di tempo - allo scopo di muoversi autonomamente, ma senza successo; entrambe le macchine avevano le ruote in movimento, ma non si muovevano di un millimetro. Alla fine si decise di fare marcia indietro individualmente ed affrontare la salita in "velocità"; il colmo fu che, arrivati nei pressi delle barriere, queste si abbassarono nuovamente e l'intera operazione dovette essere ripetuta. Difficilmente potrebbe essere d'aiuto sentirsi dispiaciuto per i non più giovani soldati che dovevano lottare così duramente per percorrere appena pochi metri, specialmente perché ciò era niente al confronto del fronte orientale, per il quale quei trattori erano stati progettati! Tuttavia, i poveri personaggi erano probabilmente felici che quella fosse l'Olanda e non Smolensk! Quello che all'Autore capitò di vedere quel giorno dovette diventare chiaro durante le prove ufficiali del veicolo due anni prima, quando furono provate ruote con diversi tipi di battistrada e ramponi, nessuna delle quali si dimostrò soddisfacente. Infatti, dal terreno di prova dell'esercito a Kummersdorf giunse un rapporto estremamente negativo sull'RSO; la debolezza principale, dichiararono, stava nelle ruote che non fornivano sufficiente trazione e davano origine ad eccessive vibrazioni, oltre a fare a pezzi malamente le strade. Sebbene si presumesse che la macchina non dovesse essere condotta a più di 16 km/h, anche se possibile, era tuttavia più scomoda su strade inghiaiate, a causa delle vibrazioni e del rumore del motore raffreddato ad aria e malamente insonorizzato. Nel frattempo, qualcos'altro era successo; alcuni membri della divisione SS Reich, in uno sforzo per mantenersi mobili in Russia durante l'inverno 1941-42, avevano sperimentato una conversione di un camion in un semicingolato. Usando i carrelli ed i cingoli di una carretta cingolata inglese in sostituzione delle ruote posteriori di un camion convenzionale, essi avevano inventato un veicolo fuori-strada dal costo relativamente basso e con prestazioni accettabili. Questo progetto ebbe così tanto successo che le autorità ordinarono a parecchi costruttori di camion di produrre un certo quantitativo dei loro autocarri 4x2 con questi carrelli cingolati come equipaggiamento installato di serie in fabbrica. Questo tipo di semicingolato divenne noto come "Maultier" (Mulo) e, alle seguenti prove comparative, nell'aprile del 1943, Hitler decise di tagliare l'intero programma Ostradschlepper in favore del Maultier, deviando le scarse materie prime da un progetto all'altro. Furono anche prodotti altri semicingolati semplificati, il leichte e lo schwere Wehrmachtschlepper (trattore militare leggero e pesante) ma fu abbastanza chiaro che la marea aveva girato contro la Germania e questi veicoli ersatz non sarebbero stati di aiuto per rovesciare la situazione. Quanti trattori Latil FTARH siano stati completati nel frattempo ad occidente nel periodo in cui l'intero progetto RSO fu abbandonato è ora materia di speculazioni, ma è improbabile che ne siano stati costruiti molti. Di sicuro, si può asserire che la forza lavoro francese non era esattamente desiderosa di mettere questo veicolo al primo posto nella produzione, per cui probabilmente inventarono abbastanza scuse per ritardare considerevolmente l'azione. Non è nemmeno sicura la quantità di RSO costruiti e consegnati dalla Skoda; basandosi su prove esistenti si può solo presumere e stimare una quantità oscillante tra i 100 ed i 200 esemplari. Comunque, Hitler non si era scordato del "suo" trattore; secondo Walter J. Spielberger nel suo libro sui trattori dell'esercito tedesco 1871-1945 (vol. 10 della serie Militärfahrzeuge, Motorbuch Verlag, Stuttgart, 1978) Hitler, nel dicembre del 1944, chiese di sapere cosa era successo agli RSO Serie O che erano stati ordinati circa due anni prima, poiché - nonostante i loro noti difetti - almeno 50 di essi furono richiesti come trattori alternativi per "scopi speciali" (questo può avere a che fare con ciò che fu detto all'Autore, allora ragazzo curioso?). Lo Skoda progettato da Porsche ed il Latil Radschlepper Ost erano dimensionalmente simili ma si potevano riconoscere da lontano: il Latil aveva un frontale molto squadrato e la sua cabina dall'aspetto primitivo era come quella di legno di tipo universale della Wehrmacht, la Einheitsfahrerhaus. Lo Skoda aveva contorni più arrotondati e sotto pelle era notevolmente simile ai trattori austriaci della I Guerra Mondiale già menzionati. Le ruote erano azionate da 4 alberi di trasmissione paralleli, che partivano a coppie "da prua a poppa" da un grosso gruppo di trasferimento, che conteneva anche i differenziali, montato a metà del telaio. Un dispositivo di blocco meccanico connetteva i due alberi di trasmissione di destra con quelli di sinistra e, di conseguenza, le relative ruote; la trasmissione incorporava un accoppiamento a fluido, che non era affatto il massimo, con tendenza al surriscaldamento durante il traino in marcia troppo alta e se sottoposto a prolungato sovraccarico; per questa ragione, fu dotato anche di una frizione monodisco a secco. L'unità motrice principale era un motore a 4 cilindri in linea raffreddato ad aria, i cui cilindri derivavano da quelli per il motore del Tigre progettato da Porsche; furono pianificate entrambe le versioni, sia con motore Otto (a benzina) che Diesel (a gasolio). I 4 grossi cilindri avevano un volume di poco superiore a 1500 cm3 ciascuno, in totale 6024 cm3, con valvole in testa; ogni testata era ampiamente alettata. Con un rapporto di compressione solamente di 5,45:1, si otteneva una potenza di 90 HP a 2100 giri/min; la versione Diesel fu progettata con un rapporto di compressione di 18:1 ed una potenza di 80 HP a 2000 giri/min, ma non raggiunse lo stadio di produzione. Per garantire un avviamento accurato, anche con temperature ambiente estremamente basse, era dotato di un motore ausiliario. Questa unità, fondamentalmente un mezzo motore Volkswagen, era flangiato all'estremità anteriore del motore principale; le sue funzioni principali erano: (a) preriscaldare il condotto di aspirazione, i cilindri e l'olio lubrificante del motore principale; (b) agire come manovella; (c) fornire riscaldamento alla cabina di guida. La cabina aveva tre posti e c'era una cuccetta posta di traverso sul retro; nel cassone posteriore di legno c'era posto per altri 8 lettini, 4 dei quali sospesi. L'aspetto piacevole del veicolo era rovinato solo dalle grandi e brutte ruote senza pneumatici; una versione con ruote gommate, forse con velocità più elevata, avrebbe potuto essere un pezzo d'equipaggiamento un po' più utile. Le informazioni sul Typ 175 fornite da Porsche nel 1982 variano in alcuni punti rispetto a quelle del 1942; pesi, altezza dal suolo e raggio di sterzata differiscono leggermente, ma ciò può essere dovuto al fatto che furono sperimentati almeno tre diversi tipi di ruote: a raggi, traforate e piene, con vari tipi di ramponi. Il Radschlepper Ost, o Porsche 175, non prestò mai servizio attivo in Russia ma è chiaro che alcuni presero la strada del fronte occidentale, nel 1944. Dopo la guerra, una decina di RSO fu scoperta nella Germania Est dove, si racconta, rimasero per parecchi anni parcheggiati in un angolo del cortile di una fattoria; essi furono alla fine demoliti, non essendo di uso pratico per nessuno. È estremamente improbabile che qualcuno di essi sia sopravvissuto fino ad oggi; un esemplare, probabilmente l'ultimo, fu dissotterrato - letteralmente - negli stabilimenti Porsche di Stoccarda. Esso fu sepolto laggiù in un fosso poco prima dell'arrivo delle truppe Alleate nel 1945; quando fu riscoperto e portato alla luce nel 1960, risultò enormemente deteriorato ed evidentemente non fu considerato degno di restauro e conservazione nel Museo Porsche. Forse nessuno ne era sufficientemente orgoglioso! Ahimé, sembra che sia andata così a molti veicoli militari di particolare interesse. CARATTERISTICHE TECNICHE Tipo: trattore pesante, 4 x 4 (Radschlepper Ost) TELAIO Marca e Modello: Skoda RSO (Porsche typ 175) Tipo: a scala Costruttore: Skoda-Werke, Pilsen, Cecoslovacchia Progetto: Dr.-Ing. h.c. F. Porsche KG, Stoccarda, Germania STERZO Tipo: vite senza fine e settore dentato MOTORE Tipo: 4 cilindri, in linea, benzina, albero a camme in testa, raffreddato ad aria FRENI Cilindrata: 6024 cm3 (115 x 145 mm) Tipo,principale e di stazionamento: meccanico, con nastri a contrazione, su tutte le ruote Potenza: 90 HP @ 2000 giri/min Coppia: 39 mkg @ 1100 giri/min RUOTE Rapporto di compressione: 5.45:1 Tipo: disco d'acciaio, diametro 1500 mm; larghezza, davanti 300 mm, dietro 400 mm, con ramponi o arpioni rimovibili Carburatore: Solex 48FNVP IMPIANTO ELETTRICO MOTORE AUSILIARIO Marca: Bosch Tipo: 2 cilindri, in linea, benzina, albero a camme in testa, raffreddato ad aria Tensione: 12 (1 batteria, 105 Ah) Cilindrata: 565 cm3 (75 x 64 mm) Potenza: 12 HP @ 3500 giri/min CARROZZERIA Coppia: 3.7 mkg @ 2000 giri/min Tipo: chiusa 3 sedili cabina con cuccetta; cassone con sponde ribaltabili, di legno, con centine e telone Rapporto di compressione: 5.8:1 Carburatore: Solex VERRICELLO Tipo: ad asse orizzontale FRIZIONE Capacità: 5000 kg Tipo: monodisco a secco più accoppiamento idraulico Marca, modello: (idraulica) Voith 384T DIMENSIONI Passo: 3000 mm CAMBIO PRINCIPALE Carreggiata, anteriore/posteriore: 1820/1720 mm Tipo: 5 marce + RM, manuale, innesti scorrevoli Lunghezza totale: 6220 mm, larghezza: 2300 mm, altezza: 3065 mm Altezza dal suolo: 490 mm (sotto gli assi) GRUPPO DI TRASFERIMENTO Tipo: singola velocità, con 4 alberi di trasmissione, differenziale centrale e dispositivo di blocco CAPACITÀ Serbatoio carburante: 250 litri ASSE ANTERIORE Tipo: rigido, con 2 pignoni e corone; giunti sterzanti incorporati PESI Rapporto: 4.00:1 A secco: 7000 kg (davanti 4000 kg, dietro 3000 kg) A pieno carico: 12000 kg ASSE POSTERIORE Sforzo di traino: 5000 kg Tipo: rigido, con 2 pignoni e corone Rapporto: 4.00:1 PRESTAZIONI Vel. max (teorica) in 1a 2.44 km/h; 2a 3.62 km/h; 3a 5.73 km/h; 4a 9.16 km/h; 5a 15.00 km/h, RM 2.92 km/h SOSPENSIONI Autonomia: 125 km Anteriore e posteriore: balestre semi-ellittiche Pendenza superabile: 33° Guado max: 1180 mm Raggio di sterzata: 14 m BIBLIOGRAFIA: articolo tratto da "Wheels & Tracks" n. 3, © ed. Battle of Britain Prints International Ltd., London, England

FRANCAIS

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ENGLISH

The various wheeled and semi-tracked tactical military vehicles which the German government and industry had designed and produced during the '30s were the cream of contemporary automotive engineering. For the takeover methods and the blitzkrieg tactics of lightning war and a quick victory the elaborate and sophisticated motor vehicles which the Wehrmacht's "elite divisions" used when they overran their neighbouring countries in 1938 - 40 were ideal. They also came out extremely well in parades, propaganda films and the like, but were far less suitable for the reality of the Eastern Front when the fighting there dragged on and got stuck in the winter of 1941/42. The extra hard work under arduous sub-zero temperatures, combined with maintenance problems, took its toll. Additional difficulties stemmed from the chronic shortage of motor vehicles, both on the Eastern Front and elsewhere. Artillery tractors in particular became scarce, partly because of the large amount of prime materials required, not to mention the man-hours needed for their elaborate manufacture. Supply just could not keep up with demand. There was also an acute shortage of horses for the horsedrawn equipment in infantry units. The transport shortage was solved to some extent by the pressing into service of captured enemy equipment, altough on the other hand this only added to the maintenance and repair problems. Moreover, few vehicles were able to cope adequately with the atrocious going and severe temperatures encountered in Russia. Both the duration of the conflict and the vaste distances into enemy territory had been grossly underrated and these miscalculations were to cost dearly. It was General von Schell who attempted to reorganize soft-skin vehicle production in Germany. His "Schell Programm" reduced the extensive overall variety of models per category - from motorcycles to trucks - to an acceptable minimum, abandoning the less suitable types and concentrating on mass-production of the best. Typical examples of this simplification scheme were the Volkswagen Kübelwagen, the 1.5-ton Steyr 1500(A) range and the 3-ton Opel "Blitz" trucks But it was Hitler himself who in November 1941 stated that there was no point in keeping in production at high expense semi-tracked artillery prime movers which would in theory last for 120 years when everybody knew that they could hardly survive more than two years of actual combat life. A new generation of much simplified tractors would have to be devised. Sophistication and superfluous detail had to be abandoned forthwith, if only to preserve high-grade materials - a very valid point indeed. Specially for the Eastern Front, the Heereswaffenamt Wa.Prüf. 6 (the appropriate Ministry department) arranged with Steyr-Daimler-Puch AG in annexed Austria for the design and manufacture of two new types of artillery tractors: the Radschlepper Ost (wheeled tractor, East) and the Raupenschlepper Ost (tracked tractor, East). For the former requirement the manufacturers came up, in January 1942, with a rather ungainly modification of the standardized Steyr 1500A 1.5-ton 4x4 truck. It featured rigid axles with spoked wheels, entirely of steel and with a diameter of 1.5 metres (nearly 5 feet). The full-track tractor wich they designed was the well-known RSO/01 which, unlike the wheeled one, soon entered quantity production in their own factories as well as those of Auto Union/Wanderer, Gräf & Stift and KHD/Magirus (RSO/03). In addition to the standard model, there was a multiplicity of derivatives, most of which remained in the experimental stage. The big-wheel was never heard of again. For the wheeled tractor project, the HWA (Heereswaffenamt) had approached Dr.-Ing. h.c. Ferdinand Porsche KG at Stuttgart-Zuffenhausen, the well-known automotive design firm, for an alternative proposal. Ferdinand Porsche (1875 - 1951) was a genius and responsible for a large variety of vehicle designs, ranging from the little KdF "people's car" (Volkswagen, including "Kübel" and amphibious "Schwimmer") to battle tanks. Hitler had in April 1942 made it known that for the new tractor requirement he wanted a tall, four-wheeled, low-speed but powerful and straightforward vehicle, not unlike the Austrian Zugmaschinen of WW1 and Porsche was the obvious choice because he had been largely responsible for such machine as the Austro-Daimler M12 and M16 of that period. At Porsche's bureau, the order from the HWA was executed under Design No. 175 (becoming Type 175) and the Skoda engineering works in Plzen (Pilsen), Czechoslovakia, were charged with the production of prototypes. Here was another parallel with the WW1 tractors: although bearing the Austro-Daimler name, these had in fact been built by Skoda, who at the time were associated with the Austrian firm. Most of the artillery pieces they pulled were also Skoda manufacture. Meanwhile, since time was pressing (Hitler wanted the tractors issued to the troops for the forthcoming winter of 1942/43), yet another alternative solution was studied. Latil of Suresnes, Seine, in occupied France and now working for the Wehrmacht under the control and supervision of Daimler-Benz AG, had for many years been supplying heavy four-wheel drive artillery tractors for the French Army. Known as the TAR-type, these had been used in large numbers in the Great War and had been further developed during the '20s and '30s (TAR3, 4, 5, TARH1, 2). Many TARH tractors had been captured by the Wehrmacht in 1939/40 and founds to be of excellent quality. The Germans even employed them, as Latil Schw. Radschlepper (f). The HWA in 1942 ordered Latil to modify their TARH design to meet Hitler's requirements, by the use of large metal wheels, using no rubber, and to get it ready for quantity production, with a thousand requires before the end of the year and a monthly delivery of a thousand units thereafter. The large wheels were a feature Hitler had great belief in; he probably recalled the performance of the Austro-Daimlers in the 1914-18 conflict, when the Austrians - his compatriots - had used relatively large numbers of them and even the Kaiser had borrowed some, complete with Skoda-built 30.5-cm mortars, in the siege of Belgian forts. Unlike Porsche, Hitler believed them to be just the job for the wretched "roads" in Russia which were just wide tracks of deep mud in which his supposedly mobile armies mired. But how wrong he was! The Ostradschlepper prototypes were tested and while they performed reasonably well in certain types of terrain, they were next to useless in snow, and particularly on icy surfaces and hard snow on metalled roads. Porsche, who had been in Russia and knew the conditions, had formed his own judgment but strangely enough Hitler and his associates never asked for his opinion. Porsche was asked to design the RSO, using as little of the scarce raw materials available as possible (no copper, no rubber for tyres) and carried it out obligingly, without questioning, which was probably just as well. The Reich's top civil servants had a working system all of their own, with strife and financial gain involved, and Porsche knew it was wiser not to interfere with them and their policies. One consequence of this system was that projects like the RSO tended to drag on, without proper supervision, taking too long and failing in the end. Porsche had worked hard and the first RSO prototypes were read for trials on October 1, 1942, barely seven months after the original orders had been given. In late October the vehicles were put through their paces at the Army's Berka test facilities near Eisenach and on November 20, Albert Speer, the Minister of War Production, witnessed a demonstration. Hitler himself first watched the Skoda and the Latil perform on January 4, 1943, in the vicinity of his headquarters in East Prussia. He was not impressed and as a result he decreed that the production order for a so-called O-series of 200 units which already been given to Skoda (i.e. AG Vorm. Skodawerke, as it was called during the war) was to be halved. Several improvements were made during these months of tests. The petrol consumption was 2 litres per kilometre, not excessive perhaps for this type of machine (and 10% less than that of the Latil), but petrol was extremely scarce and when Porsche applied to the HWA for another 4000 litres for the continuation of the tests, he was informed in writing that the request would be considered. The HWA was clearly unhappy with the RSO and in August declared that no more petrol was forthcoming because the RSO was a dead duck; Porsche was not amused. Unlike Hitler, he had never really believed that a vehicle like the Radschlepper Ost was the solution to the original problem but he had designed it because he was a designer, not a politician, and had been asked to design it. He reckoned that there were enough competent civil servants and military top brass to decide whether a requirement was valid or not and to what extent. Although Porsche had not entirely given up arguing, he knew that he was backed by Hitler, who, as Führer, had the autority to overrule both the HWA and Speer's ministry. This was often necessary in order to get something done but usually led to inter-departmental conflicts. Thus, early in 1943, the initial order for RSOs was curtailed and later that year the project terminated altogheter. Time had marched on and the Russian Front requirement for a special tractor was no more.... The writer vividly remember that in the winter of 1944/45 a column of at least a dozen of Skoda RSOs arrived in his home town in occupied Holland. They were painted the standard Einheits shade of yellowish sand and looked quite impressive. Twelve years old and all eyes and ears, he was told by one of the drivers that they were to be used (as a new and secret weapon?) in conjunction with large ploughs, to destroy railway tracks by breaking the sleepers like match sticks. It sounded both barbarous and fantastic. After a while, these Skoda's, which were highly unusual if only because were brand new, were driven to a body works just outside the town, to be camouflage-painted, two at a time. En route to this works, there was a railway level crossing, the approach to it being at a very slight incline. This was in December or January and the roads had frozen up. It also snowed. Now, due to the Wehrmacht's chronic shortage of petrol at the time, it was a rule, if not an order, for a petrol-engined vehicle, at least when empty, to take another (sometimes several others) in tow and the Skoda RSOs were no exception. In the event, two of them were struggling up to the level crossing, iron wheels of the towing unit about to loose grip, when the barriers were lowered to let a train pass and the vehicles halted. After the train had gone, the first Skoda attempted to get moving again but the huge wheels just spinned, albeit at rather a slow rate. The second vehicle was then started up - which took a fair amount of time and effort - in order to move up under its own steam, but to no avail: both machines had all their wheels revolving but did not move an inch. Eventually it was decided to reverse them individually and charge the gradient at "speed"; the tragedy was that they were back at the barriers, these were lowered again and the whole performance had to be repeated. One could hardly help feeling sorry for the not-so-young soldiers who had to fight so hard to cover just a few metres, especially since this was nothing compared with the Eastern Front, for which these tractors had been designed! Still, the poor guys were probably glad that this was Holland and not Smolensk. What the writer happened to see that day had become clear during the vehicle's official tests two years earlier, when wheels with several types of treads and cleats were tried, none of wich proved satisfactory. In fact, a very adverse report on the RSO had been given by the Army vehicle proving establishment at Kummersdorf. The chief weakness, they had claimed, lay in the wheels, which did not provide sufficient traction and gave rise to excessive vibration, besides tearing the road up very badly. Although the machine was not supposed to be driven at more than 16 km/h (10 mph), even if it could, it was indeed most uncomfortable on metalled roads, due to the vibration and the noise of the hardly insulated air-cooled engine. In the meantime, something else had happened; members of the SS division Reich, in an effort to keep mobile in Russia in the winter of 1941/42, had been experimenting with a half-track truck conversion. Using bogies and tracks of a British tracked carrier, replacing the rear wheels of a conventional truck, they had devised a relatively low-cost cross-country vehicle with acceptable performance. So successful was this design that the authorities ordered several truck manufacturers to build certain quantities of their 4x2 trucks with these tracked bogies as original factory-installed equipment. This type of half-track truck become known as "Maultier" (Mule) and following comparison trials Hitler in April 1943 decided to axe the whole Ostradschlepper programme in favour of the Maultier, scarce raw materials being diverted from the one project to the other. Other simplified half-tracks, the leichte and schwere Wehrmachtschlepper (light and heavy military tractors) were also produced but it was quite clear at this time that the tide had turned against Germany and these ersatz vehicles were not going to help to reverse the position. How many Latil FTARH tractors had in the meantime been completed in the West by the time the whole RSO project was dropped is now a matter of speculation, but it is unlikely that many were made. It can be safely assumed that the French labour force was not exactly eager to gets this vehicle into production in the first place and they probably invented enough excuses to considerably delay the action. Neither is it certain exactly how many RSOs were built and delivered by Skoda. Based on surviving evidence we can only assume and estimate that it was somewhere between one and two hundred. Hitler did not forget about "his" tractor, though. According to Walter J. Spielberger in his book about tractors of the German armies 1871 - 1945 (Vol. 10 in the series Militärfahrzeuge, Motorbuch Verlag, Stuttgart, 1978) Hitler, in December 1944, demanded to know what happened to the O-series RSOs which had been ordered nearly two years earlier, since - in spite of their known shortcomings - at least fifty of them were required as alternative tractors "for special purposes". The Porsche-designed Skoda and the Latil Radschlepper Ost were dimensionally similar but could be easily told apart. The Latil had a much squarer front and its primitive-looking cab was like the Wehrmacht's wooden universal type, the Einheitsfahrerhaus. The Skoda had more rounded contours and under the skin was remarkably similar to the Austrian WW1 tractors already mentioned. The wheels were driven by four parallel propeller shafts, running fore and aft in pairs, from a large mid-mounted transfer case which also contained the differentials. There was a mechanical locking device to connect the two prop shafts on the right and the two on the left, and thus the right-hand and the left-hand wheels. The transmission incorporated a fluid coupling, which reportedly was not quite up to the job, tending to overheat when pulling away in too high gear and under lenghty overloading; for this reason a conventional single dry plate clutch was also provided. The main power unit was an air-cooled four-in-line, built up of cylinders from the Porsche-designed Tiger tank engine. Both a petrol (Otto) and a compression ignition (Diesel) version were planned. The four large cylinders had a swept volume of just over 1500 cc each, 6024 cc in total, with the valves in amply-finned heads. With a compression ratio of only 5.45:1 a power output of 90 bhp was achieved at 2,100 rpm. the diesel version was designed to have 18:1 compression ratio and an output of 80 bhp at 2,000 rpm, but it did not reach the production stage. In order to ensure proper starting, also under extremely low ambient temperatures, an auxiliary engine was provided. This unit, basically half a Volkswagen engine, was flanged to the forward end of the main engine; its main functions were: (a) to pre-heat the inlet manifold, the cylinders and the lubricating oil of the main engine, (b) to act as a crank and (c) to provide heat for the driver's cab. The cab seated three and there was a single bunk across the back; in the wooden rear body there was room for another eight beds, four of them suspended. The non-pleasant appearance of the vehicle was spoiled only by the large and ugly tyre-less wheels. A pneumatic-tyred version with perhaps somewhat higher top speed might, in fact, have been quite a useful piece of equipment. Type 175 information supplied by Porsche in 1982 is at variance in some respects with that of 1942; weights, ground clearance and turning circle figures differ somewhat, but this may be owing to the fact that at least three different types of wheels were experimented with: spoked, perforated and solid, and with various types of spuds. The Radschlepper Ost, or Porsche 175, may never have seen active service in Russia but it is clear that a quite few found their way to the Western Front, in 1944. After the war, some ten RSOs were discovered in East Germany, where reportedly they stood for several years, parked in the corner of a factory yard. They were eventually broken up, being of no pratical use to anyone. Whether any have survived now is extremely unlikely. One example, possibly the last, was dug up - literally - at the Porsche work in Stuttgart. It had been buried there in a dike shortly before the Allied armies' arrival in 1945. When rediscovered and brought to the surface in 1960 it was found to be badly deteriorated and apparently considered not to be worthy of restoration and preservation in the Porsche museum. Perhaps nobody was sufficiently proud of it! Alas, that happens to be the way it has gone with many special-interest military vehicles. TECHNICAL CHARACHTERISTICS Type: Heavy Tractor, 4 x 4 (Radschlepper Ost) CHASSIS Make and Model: Skoda RSO (Porsche typ 175) Type: ladder frame Manufacturer: Skoda-Werke, Pilsen, Czechoslovakia Design: Dr.-Ing. h.c. F. Porsche KG, Stuttgart, Germany STEERING GEAR Type: worm and spindle ENGINE Type: 4-cyl, in-line, petrol, ohv, air-cooled BRAKES Piston displacement: 6024 cc (115 x 145 mm) Type, main and parking: mechanical, with contracting bands, on all wheels Power output/rpm: 90 bhp at 2,000 Torque/rpm: 39 mkg at 1,100 WHEELS Compression ratio: 5.45:1 Wheel type: steel disc, 1500-mm diameter; width, front 300 mm, rear 400 mm, with removable cleats or spikes Carburettor: Solex 48FNVP ELECTRICAL SYSTEM AUXILIARY ENGINE Make: Bosch Type: 2-cyl, in-line, petrol, ohv, air-cooled Voltage: 12 (1 battery, 105 Ah) Piston displacement: 565 cc (75 x 64 mm) Power output/rpm: 12 bhp at 3,500 BODYWORK Torque/rpm: 3.7 mkg at 2,000 Type: closed 3-seat cab with bunk; drop-side body, wood, with bows and canvas cover Compression ratio: 5.8:1 Carburettor: Solex WINCH Type: horizontal spindle CLUTCH Capacity: 5000 kg Type: single dry plate plus hydraulic coupling Make, model: (hydr.) Voith 384T DIMENSIONS Wheelbase: 3000 mm MAIN GEARBOX Track, front/rear: 1820/1720 mm Type: five-speed and reverse, manual, sliding gear Overall lenght: 6220 mm, width: 2300 mm, height: 3065 mm Ground clearance: 490 mm (under axles) TRANSFER CASE Type: single-speed, with four output shafts, central differentials and loking device CAPACITIES Fuel tank: 250 litres FRONT AXLE Type: rigid, with two pinions and ring gears; enclosed steering joints WEIGHTS Ratio: 4.00:1 Kerb weight: 7000 kg (front 4000 kg, rear 3000 kg) GVW: 12000 kg REAR AXLE Trailer load: 5000 kg Type: rigid, with two pinions and ring gears Ratio: 4.00:1 PERFORMANCE Max speeds (theor.) in 1st gear 2.44 km/h; 2nd gear 3.62 km/h; 3rd gear 5.73 km/h; 4th gear 9.16 km/h; 5th gear 15.00 km/h, reverse 2.92 km/h SUSPENSIONS Cruising range: 125 km Front and rear: semi-elliptic leaf springs Gradability: 33° Max fording depth: 1180 mm Turning radius: 14 m BIBLIOGRAPHY: article drawn from "Wheels & Tracks" n. 3, © ed. Battle of Britain Prints International Ltd., London, EnglandThe various wheeled and semi-tracked tactical military vehicles which the German government and industry had designed and produced during the '30s were the cream of contemporary automotive engineering. For the takeover methods and the blitzkrieg tactics of lightning war and a quick victory the elaborate and sophisticated motor vehicles which the Wehrmacht's "elite divisions" used when they overran their neighbouring countries in 1938 - 40 were ideal. They also came out extremely well in parades, propaganda films and the like, but were far less suitable for the reality of the Eastern Front when the fighting there dragged on and got stuck in the winter of 1941/42. The extra hard work under arduous sub-zero temperatures, combined with maintenance problems, took its toll. Additional difficulties stemmed from the chronic shortage of motor vehicles, both on the Eastern Front and elsewhere. Artillery tractors in particular became scarce, partly because of the large amount of prime materials required, not to mention the man-hours needed for their elaborate manufacture. Supply just could not keep up with demand. There was also an acute shortage of horses for the horsedrawn equipment in infantry units. The transport shortage was solved to some extent by the pressing into service of captured enemy equipment, altough on the other hand this only added to the maintenance and repair problems. Moreover, few vehicles were able to cope adequately with the atrocious going and severe temperatures encountered in Russia. Both the duration of the conflict and the vaste distances into enemy territory had been grossly underrated and these miscalculations were to cost dearly. It was General von Schell who attempted to reorganize soft-skin vehicle production in Germany. His "Schell Programm" reduced the extensive overall variety of models per category - from motorcycles to trucks - to an acceptable minimum, abandoning the less suitable types and concentrating on mass-production of the best. Typical examples of this simplification scheme were the Volkswagen Kübelwagen, the 1.5-ton Steyr 1500(A) range and the 3-ton Opel "Blitz" trucks But it was Hitler himself who in November 1941 stated that there was no point in keeping in production at high expense semi-tracked artillery prime movers which would in theory last for 120 years when everybody knew that they could hardly survive more than two years of actual combat life. A new generation of much simplified tractors would have to be devised. Sophistication and superfluous detail had to be abandoned forthwith, if only to preserve high-grade materials - a very valid point indeed. Specially for the Eastern Front, the Heereswaffenamt Wa.Prüf. 6 (the appropriate Ministry department) arranged with Steyr-Daimler-Puch AG in annexed Austria for the design and manufacture of two new types of artillery tractors: the Radschlepper Ost (wheeled tractor, East) and the Raupenschlepper Ost (tracked tractor, East). For the former requirement the manufacturers came up, in January 1942, with a rather ungainly modification of the standardized Steyr 1500A 1.5-ton 4x4 truck. It featured rigid axles with spoked wheels, entirely of steel and with a diameter of 1.5 metres (nearly 5 feet). The full-track tractor wich they designed was the well-known RSO/01 which, unlike the wheeled one, soon entered quantity production in their own factories as well as those of Auto Union/Wanderer, Gräf & Stift and KHD/Magirus (RSO/03). In addition to the standard model, there was a multiplicity of derivatives, most of which remained in the experimental stage. The big-wheel was never heard of again. For the wheeled tractor project, the HWA (Heereswaffenamt) had approached Dr.-Ing. h.c. Ferdinand Porsche KG at Stuttgart-Zuffenhausen, the well-known automotive design firm, for an alternative proposal. Ferdinand Porsche (1875 - 1951) was a genius and responsible for a large variety of vehicle designs, ranging from the little KdF "people's car" (Volkswagen, including "Kübel" and amphibious "Schwimmer") to battle tanks. Hitler had in April 1942 made it known that for the new tractor requirement he wanted a tall, four-wheeled, low-speed but powerful and straightforward vehicle, not unlike the Austrian Zugmaschinen of WW1 and Porsche was the obvious choice because he had been largely responsible for such machine as the Austro-Daimler M12 and M16 of that period. At Porsche's bureau, the order from the HWA was executed under Design No. 175 (becoming Type 175) and the Skoda engineering works in Plzen (Pilsen), Czechoslovakia, were charged with the production of prototypes. Here was another parallel with the WW1 tractors: although bearing the Austro-Daimler name, these had in fact been built by Skoda, who at the time were associated with the Austrian firm. Most of the artillery pieces they pulled were also Skoda manufacture. Meanwhile, since time was pressing (Hitler wanted the tractors issued to the troops for the forthcoming winter of 1942/43), yet another alternative solution was studied. Latil of Suresnes, Seine, in occupied France and now working for the Wehrmacht under the control and supervision of Daimler-Benz AG, had for many years been supplying heavy four-wheel drive artillery tractors for the French Army. Known as the TAR-type, these had been used in large numbers in the Great War and had been further developed during the '20s and '30s (TAR3, 4, 5, TARH1, 2). Many TARH tractors had been captured by the Wehrmacht in 1939/40 and founds to be of excellent quality. The Germans even employed them, as Latil Schw. Radschlepper (f). The HWA in 1942 ordered Latil to modify their TARH design to meet Hitler's requirements, by the use of large metal wheels, using no rubber, and to get it ready for quantity production, with a thousand requires before the end of the year and a monthly delivery of a thousand units thereafter. The large wheels were a feature Hitler had great belief in; he probably recalled the performance of the Austro-Daimlers in the 1914-18 conflict, when the Austrians - his compatriots - had used relatively large numbers of them and even the Kaiser had borrowed some, complete with Skoda-built 30.5-cm mortars, in the siege of Belgian forts. Unlike Porsche, Hitler believed them to be just the job for the wretched "roads" in Russia which were just wide tracks of deep mud in which his supposedly mobile armies mired. But how wrong he was! The Ostradschlepper prototypes were tested and while they performed reasonably well in certain types of terrain, they were next to useless in snow, and particularly on icy surfaces and hard snow on metalled roads. Porsche, who had been in Russia and knew the conditions, had formed his own judgment but strangely enough Hitler and his associates never asked for his opinion. Porsche was asked to design the RSO, using as little of the scarce raw materials available as possible (no copper, no rubber for tyres) and carried it out obligingly, without questioning, which was probably just as well. The Reich's top civil servants had a working system all of their own, with strife and financial gain involved, and Porsche knew it was wiser not to interfere with them and their policies. One consequence of this system was that projects like the RSO tended to drag on, without proper supervision, taking too long and failing in the end. Porsche had worked hard and the first RSO prototypes were read for trials on October 1, 1942, barely seven months after the original orders had been given. In late October the vehicles were put through their paces at the Army's Berka test facilities near Eisenach and on November 20, Albert Speer, the Minister of War Production, witnessed a demonstration. Hitler himself first watched the Skoda and the Latil perform on January 4, 1943, in the vicinity of his headquarters in East Prussia. He was not impressed and as a result he decreed that the production order for a so-called O-series of 200 units which already been given to Skoda (i.e. AG Vorm. Skodawerke, as it was called during the war) was to be halved. Several improvements were made during these months of tests. The petrol consumption was 2 litres per kilometre, not excessive perhaps for this type of machine (and 10% less than that of the Latil), but petrol was extremely scarce and when Porsche applied to the HWA for another 4000 litres for the continuation of the tests, he was informed in writing that the request would be considered. The HWA was clearly unhappy with the RSO and in August declared that no more petrol was forthcoming because the RSO was a dead duck; Porsche was not amused. Unlike Hitler, he had never really believed that a vehicle like the Radschlepper Ost was the solution to the original problem but he had designed it because he was a designer, not a politician, and had been asked to design it. He reckoned that there were enough competent civil servants and military top brass to decide whether a requirement was valid or not and to what extent. Although Porsche had not entirely given up arguing, he knew that he was backed by Hitler, who, as Führer, had the autority to overrule both the HWA and Speer's ministry. This was often necessary in order to get something done but usually led to inter-departmental conflicts. Thus, early in 1943, the initial order for RSOs was curtailed and later that year the project terminated altogheter. Time had marched on and the Russian Front requirement for a special tractor was no more.... The writer vividly remember that in the winter of 1944/45 a column of at least a dozen of Skoda RSOs arrived in his home town in occupied Holland. They were painted the standard Einheits shade of yellowish sand and looked quite impressive. Twelve years old and all eyes and ears, he was told by one of the drivers that they were to be used (as a new and secret weapon?) in conjunction with large ploughs, to destroy railway tracks by breaking the sleepers like match sticks. It sounded both barbarous and fantastic. After a while, these Skoda's, which were highly unusual if only because were brand new, were driven to a body works just outside the town, to be camouflage-painted, two at a time. En route to this works, there was a railway level crossing, the approach to it being at a very slight incline. This was in December or January and the roads had frozen up. It also snowed. Now, due to the Wehrmacht's chronic shortage of petrol at the time, it was a rule, if not an order, for a petrol-engined vehicle, at least when empty, to take another (sometimes several others) in tow and the Skoda RSOs were no exception. In the event, two of them were struggling up to the level crossing, iron wheels of the towing unit about to loose grip, when the barriers were lowered to let a train pass and the vehicles halted. After the train had gone, the first Skoda attempted to get moving again but the huge wheels just spinned, albeit at rather a slow rate. The second vehicle was then started up - which took a fair amount of time and effort - in order to move up under its own steam, but to no avail: both machines had all their wheels revolving but did not move an inch. Eventually it was decided to reverse them individually and charge the gradient at "speed"; the tragedy was that they were back at the barriers, these were lowered again and the whole performance had to be repeated. One could hardly help feeling sorry for the not-so-young soldiers who had to fight so hard to cover just a few metres, especially since this was nothing compared with the Eastern Front, for which these tractors had been designed! Still, the poor guys were probably glad that this was Holland and not Smolensk. What the writer happened to see that day had become clear during the vehicle's official tests two years earlier, when wheels with several types of treads and cleats were tried, none of wich proved satisfactory. In fact, a very adverse report on the RSO had been given by the Army vehicle proving establishment at Kummersdorf. The chief weakness, they had claimed, lay in the wheels, which did not provide sufficient traction and gave rise to excessive vibration, besides tearing the road up very badly. Although the machine was not supposed to be driven at more than 16 km/h (10 mph), even if it could, it was indeed most uncomfortable on metalled roads, due to the vibration and the noise of the hardly insulated air-cooled engine. In the meantime, something else had happened; members of the SS division Reich, in an effort to keep mobile in Russia in the winter of 1941/42, had been experimenting with a half-track truck conversion. Using bogies and tracks of a British tracked carrier, replacing the rear wheels of a conventional truck, they had devised a relatively low-cost cross-country vehicle with acceptable performance. So successful was this design that the authorities ordered several truck manufacturers to build certain quantities of their 4x2 trucks with these tracked bogies as original factory-installed equipment. This type of half-track truck become known as "Maultier" (Mule) and following comparison trials Hitler in April 1943 decided to axe the whole Ostradschlepper programme in favour of the Maultier, scarce raw materials being diverted from the one project to the other. Other simplified half-tracks, the leichte and schwere Wehrmachtschlepper (light and heavy military tractors) were also produced but it was quite clear at this time that the tide had turned against Germany and these ersatz vehicles were not going to help to reverse the position. How many Latil FTARH tractors had in the meantime been completed in the West by the time the whole RSO project was dropped is now a matter of speculation, but it is unlikely that many were made. It can be safely assumed that the French labour force was not exactly eager to gets this vehicle into production in the first place and they probably invented enough excuses to considerably delay the action. Neither is it certain exactly how many RSOs were built and delivered by Skoda. Based on surviving evidence we can only assume and estimate that it was somewhere between one and two hundred. Hitler did not forget about "his" tractor, though. According to Walter J. Spielberger in his book about tractors of the German armies 1871 - 1945 (Vol. 10 in the series Militärfahrzeuge, Motorbuch Verlag, Stuttgart, 1978) Hitler, in December 1944, demanded to know what happened to the O-series RSOs which had been ordered nearly two years earlier, since - in spite of their known shortcomings - at least fifty of them were required as alternative tractors "for special purposes". The Porsche-designed Skoda and the Latil Radschlepper Ost were dimensionally similar but could be easily told apart. The Latil had a much squarer front and its primitive-looking cab was like the Wehrmacht's wooden universal type, the Einheitsfahrerhaus. The Skoda had more rounded contours and under the skin was remarkably similar to the Austrian WW1 tractors already mentioned. The wheels were driven by four parallel propeller shafts, running fore and aft in pairs, from a large mid-mounted transfer case which also contained the differentials. There was a mechanical locking device to connect the two prop shafts on the right and the two on the left, and thus the right-hand and the left-hand wheels. The transmission incorporated a fluid coupling, which reportedly was not quite up to the job, tending to overheat when pulling away in too high gear and under lenghty overloading; for this reason a conventional single dry plate clutch was also provided. The main power unit was an air-cooled four-in-line, built up of cylinders from the Porsche-designed Tiger tank engine. Both a petrol (Otto) and a compression ignition (Diesel) version were planned. The four large cylinders had a swept volume of just over 1500 cc each, 6024 cc in total, with the valves in amply-finned heads. With a compression ratio of only 5.45:1 a power output of 90 bhp was achieved at 2,100 rpm. the diesel version was designed to have 18:1 compression ratio and an output of 80 bhp at 2,000 rpm, but it did not reach the production stage. In order to ensure proper starting, also under extremely low ambient temperatures, an auxiliary engine was provided. This unit, basically half a Volkswagen engine, was flanged to the forward end of the main engine; its main functions were: (a) to pre-heat the inlet manifold, the cylinders and the lubricating oil of the main engine, (b) to act as a crank and (c) to provide heat for the driver's cab. The cab seated three and there was a single bunk across the back; in the wooden rear body there was room for another eight beds, four of them suspended. The non-pleasant appearance of the vehicle was spoiled only by the large and ugly tyre-less wheels. A pneumatic-tyred version with perhaps somewhat higher top speed might, in fact, have been quite a useful piece of equipment. Type 175 information supplied by Porsche in 1982 is at variance in some respects with that of 1942; weights, ground clearance and turning circle figures differ somewhat, but this may be owing to the fact that at least three different types of wheels were experimented with: spoked, perforated and solid, and with various types of spuds. The Radschlepper Ost, or Porsche 175, may never have seen active service in Russia but it is clear that a quite few found their way to the Western Front, in 1944. After the war, some ten RSOs were discovered in East Germany, where reportedly they stood for several years, parked in the corner of a factory yard. They were eventually broken up, being of no pratical use to anyone. Whether any have survived now is extremely unlikely. One example, possibly the last, was dug up - literally - at the Porsche work in Stuttgart. It had been buried there in a dike shortly before the Allied armies' arrival in 1945. When rediscovered and brought to the surface in 1960 it was found to be badly deteriorated and apparently considered not to be worthy of restoration and preservation in the Porsche museum. Perhaps nobody was sufficiently proud of it! Alas, that happens to be the way it has gone with many special-interest military vehicles. TECHNICAL CHARACHTERISTICS Type: Heavy Tractor, 4 x 4 (Radschlepper Ost) CHASSIS Make and Model: Skoda RSO (Porsche typ 175) Type: ladder frame Manufacturer: Skoda-Werke, Pilsen, Czechoslovakia Design: Dr.-Ing. h.c. F. Porsche KG, Stuttgart, Germany STEERING GEAR Type: worm and spindle ENGINE Type: 4-cyl, in-line, petrol, ohv, air-cooled BRAKES Piston displacement: 6024 cc (115 x 145 mm) Type, main and parking: mechanical, with contracting bands, on all wheels Power output/rpm: 90 bhp at 2,000 Torque/rpm: 39 mkg at 1,100 WHEELS Compression ratio: 5.45:1 Wheel type: steel disc, 1500-mm diameter; width, front 300 mm, rear 400 mm, with removable cleats or spikes Carburettor: Solex 48FNVP ELECTRICAL SYSTEM AUXILIARY ENGINE Make: Bosch Type: 2-cyl, in-line, petrol, ohv, air-cooled Voltage: 12 (1 battery, 105 Ah) Piston displacement: 565 cc (75 x 64 mm) Power output/rpm: 12 bhp at 3,500 BODYWORK Torque/rpm: 3.7 mkg at 2,000 Type: closed 3-seat cab with bunk; drop-side body, wood, with bows and canvas cover Compression ratio: 5.8:1 Carburettor: Solex WINCH Type: horizontal spindle CLUTCH Capacity: 5000 kg Type: single dry plate plus hydraulic coupling Make, model: (hydr.) Voith 384T DIMENSIONS Wheelbase: 3000 mm MAIN GEARBOX Track, front/rear: 1820/1720 mm Type: five-speed and reverse, manual, sliding gear Overall lenght: 6220 mm, width: 2300 mm, height: 3065 mm Ground clearance: 490 mm (under axles) TRANSFER CASE Type: single-speed, with four output shafts, central differentials and loking device CAPACITIES Fuel tank: 250 litres FRONT AXLE Type: rigid, with two pinions and ring gears; enclosed steering joints WEIGHTS Ratio: 4.00:1 Kerb weight: 7000 kg (front 4000 kg, rear 3000 kg) GVW: 12000 kg REAR AXLE Trailer load: 5000 kg Type: rigid, with two pinions and ring gears Ratio: 4.00:1 PERFORMANCE Max speeds (theor.) in 1st gear 2.44 km/h; 2nd gear 3.62 km/h; 3rd gear 5.73 km/h; 4th gear 9.16 km/h; 5th gear 15.00 km/h, reverse 2.92 km/h SUSPENSIONS Cruising range: 125 km Front and rear: semi-elliptic leaf springs Gradability: 33° Max fording depth: 1180 mm Turning radius: 14 m BIBLIOGRAPHY: article drawn from "Wheels & Tracks" n. 3, © ed. 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