VEICULOS E ARMAMENTOS MILITARES: LVTP-5

segunda-feira, 8 de março de 2021

LVTP-5

Amphibious APC - 1120 construído

“Sempre-Fi”: a geladeira do Nam nas faixas

O LVTP-5 é um exemplo perfeito de um produto manufaturado que claramente torna a funcionalidade superior a qualquer outra consideração. Feio e pesado, foi a evolução direta de uma longa linha de LVTPs (Landing Vehicle, Track, Personnel) que serviu no Pacífico durante ww2. Essa experiência foi passada para uma nova geração de veículos. Uma corajosa tentativa de modernizar o conceito do tipo, o LVTP-5 foi definido no mesmo período que os primeiros veículos blindados de transporte de pessoal do FCM no início dos anos 1950 e entrou em serviço em 1956 com o USMC. Totalmente fechado, ele podia transportar 30-35 fuzileiros navais totalmente equipados, tinha 9 metros de comprimento e quase quarenta toneladas. Tarde demais para a guerra da Coréia, o LVTP-5 teve ampla ação durante a guerra do Vietnã.

Desenvolvimento

O anterior LVT (A) -5 (1945) era um veículo de apoio de assalto derivado do LVT (A) -4 com uma torre motorizada e um giroestabilizador para a torre do obus de 75 mm. (269 unidades produzidas, em serviço a tempo da guerra da Coréia). O seguinte LVT-3C do pós-guerra (1949) foi relacionado ao LVT-3 , mas com um teto blindado e com a proa estendida para melhorar a flutuabilidade. Foi seguido pela conversão de cerca de 1.200 LVT-3 que participaram da Guerra da Coréia. O LVT-4 LGTWGT (1945) foi uma conversão da qual pouco se sabe. O corpo de fuzileiros navais dos EUA lançou especificações para um APC anfíbio totalmente fechado em 1947. Dois contratantes principais responderam a tempo e foram capazes de entregar os protótipos: a empresa BorgWarner e a FMC.

A segunda geração começou com os protótipos LVTPX3 (1950) e LVTPX2 (1952). O primeiro foi projetado pela FMC em 1947, um dos vários
amtracs experimentais desenvolvidos imediatamente após a guerra na tentativa de examinar novas abordagens e configurações. No entanto, nenhum deles entrou em produção até a Guerra da Coréia, forçando a Marinha a improvisar com o LVT-3C.

LVTP-6 paralelo da FMC

Este último foi o projeto rival desenhado pela empresa BorgWarner em 1947. Ele teve algumas modificações no motor, além de quatro tipos de transmissões testadas, com um total de cinco protótipos produzidos. O LVTP-X2 (I) tinha um motor Cadillac Co. Model331 tipo V de 8 cilindros (187,5 cv). O LVTP-X2 (II) tinha o mesmo motor de seis cilindros da série GMC Inc. Modelo 302 que o protótipo M59 (127 cavalos de potência, 3.350 rev / 146 hp / rotação de 3.600) equipado com protótipos dos 2 grupos. Apenas dois foram fabricados. O LVTP-X2 (III) ganhou o motor Chrysler Corp. tipo V de 8 cilindros (197 cv) e outro da mesma série testou a transmissão automática Chrysler “Powerflyte”. O LVTP-X2 (III-2) tinha o Chrysler Corp. V8 (197 cv) que foi selecionado para o veículo de produção em massa e se tornou o LVTP-6. O LVTP-X2 (III) também recebeu a mesma transmissão automática General Motors FS-301MG que o protótipo M59. O LVTP-6 acabará sendo o desenvolvimento paralelo malsucedido da FMC para o LVTP-5 baseado no exército da Borg-WarnerM59 APC , mas nunca entrou em produção em massa.

Em tamanho, o primeiro M44 APC da FMC era o que estava mais próximo em termos de capacidade de carga do LVTP-5, com 27 homens mais a tripulação.

O novo trator anfíbio AMTRAC / APC surgiu com o fim da guerra na Coréia. As unidades de tratores anfíbios marinhos estavam em más condições,
com um total de 539 LVTs de vários modelos retornando em muito mau estado. Eles foram reconstruídos mais uma vez no Mare Island Navy Yard, mas estavam rapidamente chegando ao fim de sua vida útil. Aqueles que estavam em melhor forma foram entregues às forças aliadas da marinha sob o programa MAP, especialmente os taiwaneses e sul-coreanos, portanto, novos LVTs foram necessários para cobrir até mesmo as necessidades básicas do USMC.

Mesmo antes da eclosão da guerra da Coréia, o Escritório Naval de Navios decidiu seguir em frente com um programa de LVT totalmente novo baseado nas tecnologias mais recentes e testes em andamento conduzidos desde 1946. Um contrato em dezembro de 1950 foi emitido para a Divisão de Produtos Ingersoll 01 da Borg-Warner Corporation para o desenvolvimento de uma nova família de amtracs. Quatro variantes também deveriam ser derivadas do projeto básico que veio a ser o LVTP-5, a saber, um veículo de apoio de artilharia, comando e rádio, defesa aérea, engenharia de recuperação e combate / veículo de limpeza de campos de minas.
O novo tamanho do Amtrack também era notável, com 35 toneladas descarregadas e projetado para transportar 30-31 fuzileiros navais equipados (que era o dobro dos Amtracks anteriores).

O primeiro protótipo, o porta-armas LVTH-6 foi concluído em agosto de 1951. O desenvolvimento paralelo da FMC, veja acima, foi rejeitado porque as necessidades da Marinha estavam muito distantes do que as da Marinha e o M59 era muito pequeno e apenas capaz de cruzar grandes rios e lagos, mas não viajava longas distâncias se possível em mar agitado e exigia melhor manobrabilidade na água. O M59 foi, portanto, totalmente reconstruído para melhorar suas características de flutuabilidade e propulsão na água. Enquanto isso, os testes com amtracs Borg-Warner foram bem-sucedidos, concluindo em 1952 com a produção do porta-tropas LVTP-5 padronizado (e LVTP6). Eventualmente, a decisão foi tomada para prosseguir com a produção do LVTP-5 sozinho, enquanto o LVTP-X2 menor e mais barato deveria ser um projeto que pudesse complementar o LVTP-5 no longo prazo.

A gun carrier and air defence version were soon developed, at the same time as the troop carrier. In 1956 eventually the FMC design was accepted for Marine service as the LVTP-6, but by that time, production of the LVTP-5 was almost complete and the awaited order never placed for mass production. So 1,124 LVTP-5s and 210 LVTH-6s were ultimately built until 1957.
58 LVTP-5S were later converted into command vehicles, redesignated LVTP-5, and a small number LVTE-1 engineering vehicle and 65 LVTR-l recovery vehicles saw the light of the day. Apparently, no LVTAA-l for air defense was ever built past the prototype stage.

Design

The general shape of the vehicle was indeed dictated by practicality, and the tracks imposed a parallelepipedic hull with smooth angles and slopes, which indeed looked almost like an average household fridge. It was easy to distinguish the vehicle from ww2 LVTs also, like the fully enclosed compartment, and low-slung tracks (and not all-enveloping tracks) that were reminiscent of a millipede. The 9 meters long hull was built of welded RHA steel, but the level of protection was light, about 8 mm at best.

The top of the structure saw two cupolas at the front (driver and commander, left and right) while the main compartment was extended from the front to the rear without interruption but for the storage, fuel tanks, and of course the engine compartment at the rear end. The troops disembarked from the frontal ramp like any LST. The bay was large enough to accommodate a jeep. The LVTP-5 existed as an unarmed cargo version as well as a personnel transport, with an MG cupola for ground support located at the front of the roof.

The Driver sat in the bow, port (left) side, while the Commander sat at the starboard bow, and the third member, sometimes called Assistant Driver but acting as a Gunner depending on the type was seated on the left and was given a cupola with the 0.3 cal. M1919A4 machine gun. The vehicle capacity was between 25 and 34 fully equipped Marines, seated in four rows of folding bench seats. The central row was back to back. But when folded or dismounted, as many as 45 passengers could be transported standing up.

This was even the usual practice in Vietnam, the exception being shore duty over extended distances. Payload was impressive, 12,000lbs when swimming for buoyancy reasons, but up to 18,000lbs on firm ground. The loading ramp was lowered by electrically powered cable, with a manual backup. However, there were also large hinged doors on the roof when at sea. For the crew exit/access, four more hatches were placed on the roof, behind the hinged doors and at the rear.

Propulsion was assumed by a Continental V-12, which was a sturdy liquid-cooled gasoline engine, which remained constant throughout the years but for a few exhaust and air intake modifications, along with a revised roof vent system in the late production. However, during and after development, a number of suspension and powertrain problems soon plagued the early LVTP-5 until full deployment in 1956. The LVTP-5 shared their transmission with the M47 and M48 tanks, but due to their powertrain configuration, the final drives were about 3 feet below the transmission output shafts, requiring a dropgear assembly to couple the final drives and transmissions, proving a frequent source of mechanical failures. Improvements to these, as well as the additional box snorkel and top deck ventilators solved part of these problems, designated LVTP-5A1, and LVTH-6Al.

Variants

LVTE-1: The engineering variant. It was given a large toothed V-shaped excavator blade mounted on the nose of the vehicle, that could clear its path through a minefield 3.7 m wide and up to 0.41 m deep. Plastic-foam buoyancy tanks were also fitted in the inside if the blade to keep the nose up when swimming. On the roof was mounted a rocket-propelled line charge, elevated hydraulically. A 0.3 cal. machine gun cupola was maintained between the driver and commander’s ones. Late production vehicles were given a Continental AVI-1790-8 12 cylinder fuel injected gasoline also shared by the M48A2 tank. They did lack the recessed radiators on the sides or the exhaust and air intake protections on the roof. 41 were built in total.
LVTC-5 : Landing Vehicle, Tracked, Command, command vehicle.
LVTH-6 : Landing Vehicle, Tracked, Howitzer- fire support variant armed with M49 105 mm howitzer. 210 units built.
LVTR-1 : Landing Vehicle, Tracked, Recovery- recovery vehicle. 65 units built.
LVTAA-X1 : Landing Vehicle, Tracked, Anti-Aircraft variant, to be fitted with the turret of the M42 Duster. Prototype only.

Exports

There is no record of LVTP-5s being used by the South Vietnamese army after the departure of the last US troops in 1973, however some were sold in the 1980s to the Republic of China, given to the Marines (ROCM -no longer in service), the Philippine Marines (4 still in service), and the Chilean Marines (apparently no longer in service).

Philippine Marines LVTPH1A1 as if today. Notice the digital camo (wikipedia)

The LVTP-5 in Vietnam

Marine amphibian tractor battalions fielded 20 LVTs each. The two tractor companies had four platoons each with eleven LVTP-5A1s, while the battalion HQ had three LVTP-5A1 Command vehicles, one LVTR-1A1 recovery vehicle, a mine clearance platoon with eight LVTE-1 ‘Potato Diggers’, a maintenance platoon with one LVTR-1A1; and an amphibian platoon with three LVTP-5A1 (Cmd) plus 12 LVTP-5A1 troop carriers. Until the late 1960s,
these battalions were organic the USMC divisions.

During the Vietnam war, the 1st and 3d Amphibian Tractor Battalions were deployed with the USMC 3rd and 1st Divisions. The nature of the fighting in Vietnam was ill-suited for traditional amtrac operations, as there were few contested beach assaults. The amtracs were very large and bulky and on land the nimbler M113 were preferred as troop transports. Although they were considerably more durable than amtracs of ww2, LVTP-5s were not intended for prolonged land operations as their torsilastic suspensions suffered from excessive wear on an uneven ground they were not designed for.
The powertrain was equally difficult to serve and worn-out engine or transmission took an entire day to be replaced.

The biggest issue was the configuration of the fuel cells in the floor: In Vietnam, landmines were a constant danger for AFVs, so much so that troops often preferred to ride on the roof rather inside; As noted, a mine detonation under an LVTP-5 belly often set alight the petrol tanks, causing mayhem in the crew compartment. As a result, the use of amtracs was restricted or the command gave them only specific terrain-oriented missions suited to their profile such as coastline and riverbanks patrols, coastal operations and supply cargo from rear areas, or sea-to-shore transport from the fleet. The basic troop carrier saw active service but the other variants also, if not perhaps more, like the LVTH-6A 1 frequently used for indirect artillery support.

Further developments

Rare LVTP-X developed by FMC, competing against the current LVTP-7.

The LVTP-7 was the result of these Vietnam lessons, and this process began as early as 1963. FMC but also Chrysler participated in it, and specifications called notably for a much longer service life (15 years as designed for the LVTP-5), ease of maintenance and base versatility. A lot of effort was also put in the design of a more land-oriented or land-capable suspensions and drivetrain. This is another chapter that we will tackle one day, but the experience and lessons eventually gave after a long development a much better vehicle which is today still in service and probably will remain so for years.

Links/sources

The LVTP-5 on wikipedia
Old archive on oocities
amtrac.org
Another development article
The AFV Kit (article)

LVTP-5 specifications
Dimensions	9 x3.57 x2.92 m (29 x 11.7 x 9.6 ft)
Total weight, battle ready	37.4 tons (74,800 Lbs)
Crew	3+34 (driver, commander, gunner, 34 infantry)
Propulsion	Continental LV-1790-1 V-12 gasoline 704 hp P/w 19 hp/tonne
Suspension	Torsilastic
Speed (road)	48 land/11 km/h water (30/6.8 mph)
Range	306 land/92 km water (190/57 mi)
Armament	APC 0.3 cal. M1919A4 (8 mm)
Armor	25 mm max (0.9 in)
Total production	1,124 in 1956-1957

LVTP-5

LVTP-5 visto do outro lado “Quem é o próximo”

LVTP-5, unidade desconhecida, Da Nang 1969

LVTP-5A1 LVTE-1 'Potato Digger' usado para suporte de engenheiros e invasão de campos minados, equipado com uma combinação de ancinho de lâmina de escavadeira na frente. A grande estrutura no telhado é o lançador para a carga de linha de demolição propelida por foguete (FMC Corp.) LVTPH-6 ou LVTH-6A1 porta-armas, equipado com o obuseiro de 105 mm para fornecer suporte de artilharia durante as operações amtrac. Podia transportar 151 cartuchos armazenados em racks, além de 150 cartuchos enlatados no porão de carga, durante as operações terrestres. Por segurança, não mais do que 100 cartuchos eram normalmente carregados. ROCA LVTP-5A1 LVTPH-6 Howitzer Fuzileiros Navais das Filipinas