Fokker T.V bomber [T.5]
Introduction
The Fokker T-V bomber was the only true bomber plane of the Dutch airforce in May 1940. And it had not even been intended as a genuine bomber too, when its initial design was started. In 1936 the emphasize had been on designing a light and a heavy fighter cruiser. The first had resulted into the G-1, the second into the T-V. But the T-V was later designated as a medium bomber for it would be to rigid to serve as a fighter-cruiser.
Fokker applied mysterieus type designations for its designs. The T stood for Bomber, the G for fighter-cruiser, the D for fighter and the C for reconnaissance.
Design and construction
In May 1936 funds were made available to design and built a prototype of a totally new military airplane type for the Dutch airforce: it would be a fighter-cruiser, what one nowadays would dedicate as a fighter-bomber. Fokker was awarded the contract because the government insisted on indigenous design and production. One should bear in mind that up to that point the most modern operational Dutch plane that was able to deliver bombs, was the C.X biplane. This was a design of the previous generation of planes, with very basic bomb-racks under the wings. These racks in particular had given much trouble before they had worked effectively. With the order of the T.V a whole new principle of [Dutch] bomber-design was initiated.
The clarification meetings that were held over the design philosophy and design demands were so extensive that no less than 124 meetings were (considered) necessary between the representatives of the Fokker design department and the military purchasers! The demands in relation to the variety of payloads the plane was required to carry [and deliver] resulted in a specification that prescribed no less than 23 different configurations. Apart from this ridiculous demand, some of the bombs that the T.V was supposed to be able to carry did not even exist at the time of specification. As such Fokker had to leave the design for the bomb-bay and the bomb-hatches undefined.
The discussions dragged on and on, and when in October 1936 still no progress had been achieved with the actual construction of the plane the Chief of the General Staff [in those days the most senior in command], General Reynders, protested at the Ministry of Defence over the obstructions the military purchasing department caused in the construction progress. Not only was the General not amused by the delay of the T.V itself, but he also expressed his great concern about the slow progress of the airforce expansion in general. He demanded that the defence purchasers would source suitable planes - fighters and dedicated bombers - abroad. He predicted - and how right he was - that modern warfare could not survive without the availability of plenty of modern dedicated bombers. He lacked any confidence in the Dutch indigenous industry to fill this gap in the lines. But ... his appeal was quite in vain. His words were hardly heard.
The initial intention had been to order 48 fighter-cruisers, which would form three squadrons of 16 planes each. It was later decided that the planes would be designed and equipped as medium bombers. In January 1937 the Ministry of Defence ordered 16 T.V's. At that point two follow-up orders for the next 32 T.V's were still scheduled. Notwithstanding the previously addressed written plead by General Reynders, the Minister of Defence [or Secretary of Defence] cut the budget for these squadrons early 1938 resulting in the cancellation of any plans to order the other 32 planes. Money was needed elsewhere and bombers were considered less important than other weaponry ...
The first plane was ordered as a flying mock-up, based on which the military purchasers would decide on the final internal configuration of the other 15 planes. This very odd contract-construction - ordering a production series of planes without the prior testing of a flying prototype - posed Fokker with all kinds of design queries that had to be answered during production and trials. The bomb-bay compartment was improvised awaiting a final decision on the types, shape and weight of the bombs. Furthermore a selection of the type of bomb-rack had to be made. The Dutch themselves did not produce any type of suitable bomb-rack and so for the time being a German [Heber] rack was selected for the first two planes. The nose section also awaited a final decision on the type of nose-gun [it would be a 20 mm gun - that was certain already].
Regarding the bomb-rack an interesting and extended discussion followed. Fokker had requested the Dutch company Van Heyst to design a bomb-rack suitable for the T.V bomb-bay. Van Heyst had previously delivered the bomb-racks for the C.X which had caused all kinds of problems with the [gas-cartridge] release mechanism. Meanwhile Heber remained in contact with Fokker and stated they would be able to design a suitable tailor-made rack, based on an electro-magnetic release mechanism. Van Heyst continued to redesign new racks but time and again failed to meet the requirements. Then the decision was made to order two Heber racks and build the other racks in license. This decision came too late for the bombers to be equipped with the efficient German racks in May 1940. In the end - at 10 May 1940 - 2 of the T.V bombers were equipped with the Heber racks, whilst the other 14 planes had old racks of civil KLM planes [that could be fitted with old racks in order to use the planes as auxiliary bombers] installed! It would have serious consequences for the pay-load of the T-V's, that were as such only able to drop 400-600 kg bombs in stead of 1,200 kg!
In September 1937 the flying mock-up was towed out of the Fokker hangar. In October it would make its maiden flight. The plane was designated the 850 [the next planes would be the 851 u/I 865]. It was equipped with two Bristol Pegasus XX engines, although the contract had stated that Pegasus XXVI engines would be built-in. These were not available yet, but the other planes would indeed be equipped with the XXVI engines. An extended discussion was once again started about the camouflage colours and pattern, and it wasn't before February 1938 before the 850 was shown with the final painting finish. Numerous small changes to the design followed, after which the plane was 90% ready in June 1938. It only failed the final nose-section because the nose gun had not been selected yet.
Meanwhile the 851, 852 and 853 left the production hall. The delivered planes still had to go to a series of adaptations, such as added camera-positions, communication instruments and adjustments to the rudder. The planes were tested and proved better than expected in many ways, with exception to the required take-off distance which proved slightly longer. The better speed performance was - surprisingly enough - caused by the Pegasus XX engines that proved to outperform the better predicted XXVI type. The reason was later determined in the two-pitch propeller mode of the XX rather than the auto-pitch of the XXVI type.
Although the planes were accepted by the airforce, they turned out to have a very vulnerable hydraulic system. Pressure vessels and hydraulic piping presented all kinds of challenges to the designers and constructors. All kinds of troubles were experienced with the T.V, which were partially related to lack of spare parts [as a consequence of the late selection of the final plane design Fokker had not yet produced any spares]. In the end the test trials were finalized with the seventh plane delivered, the 856. It was September 1939 ...
It wasn't the end of the ordeal. The hydraulic system of all delivered planes had to be replaced because the selected French product failed totally. Also the gear hydraulics posed problems and as such on many occasions the crew had to use the manual pump to lower the wheels!
Then it turned out that the oil consumption of the engines far exceeded the Bristol specification. The problems would never be actually solved, not even when Bristol themselves got involved. A third problem was the interference of the radio during operation that would later be determined as caused by the engine sparks. A problem that today is well known and solved by isolating the engines, but in those days it was quite new. Just before war break-out this problem was solved.
Yet another challenge hit the desks of the airforce commanders. There was a huge shortage of trained twin-engine plane pilots and observers. This shortage was created by the lack of a sufficient number of planes to train the crews. A deal was established with the KLM, and pilots were exchanged. In the end many T.V pilots were designated as auxiliary KLM pilots, and as such yet another problem was solved.
The everlasting problems with the huge oil consumption made the T.V unsuitable for prolonged flights, and as such it was hardly ever used for patrolling the skies during the period September 1939 - May 1940. During one of the rare patrol flights, in April 1940, one of the few T.V's [864] had to make a crash landing and was seriously damaged. The expansion of the hydro-oil tanks improved the flight duration, but did not solve the problem with the oil consumption.
The armament of the Fokker T.V was not addressed yet. Since the plane was originally designated to become a fighter-cruiser cable of carrying just a small payload of bombs, it was quite heavily armed [for a bomber]. In the end the selected nose-gun had become the Solothurn 20 mm gun, which was not capable of automatic fire. It was a man-operated single-shot gun, although it was capable of rapid fire since it had a half-automatic action. Furthermore three 7.9 mm FN machineguns were divided over as many machinegun positions at all angles [top, bottom, rear] of the fuselage.
The plane was able to carry maximum pay-loads of 1,200 kg [4 x 300 kg] although in practise only the two T.V's equipped with Heber-type racks were indeed capable to carry this maximum load. The 14 T.V's with older rack types could only carry 400 kg of bombs [or 2 x 300 kg]. Usually 4 off 50 kg bombs and 2 off 100 kg bombs were carried, sometimes 8 x 50 kg [with a slightly adapted rack].
The bomb aiming devices were also delivered short. This meant that some T-V's had no or older aiming devices. Another flaw in the design was the poor fuel tank construction that was highly vulnerable.
May war
At 10 May 1940 only 9 out of 16 planes were ready for action. None of the other 7 planes could be successfully prepared for action during the May War. All these planes - with exception of 1 at Texel - were stationed at Schiphol AFB.
The Fokker T.V was quite a capable medium bomber in 1940. Although obviously considerably slower than the German fighters, it did not under-perform in comparison to for example the British Wellington, the German Dornier Do-17 and Heinkel-111 or the French Potez 630. The obvious limitation of the improvised bomb-racks was a huge disadvantage though. The armament of the T.V outmatched all aforementioned competitors.
Obviously the T.V - that was active as a tactical bomber during the May War - was available in too little a number to make any difference. Still, the plane could be considered quite modern and capable in May 1940.
The T-V's flew quite a considerable number of missions. The AFB's Waalhaven and Ockenburg were raided as well as the bridges in the heart of Rotterdam and at Moerdijk. In case of the latter it was the only mission where 300 kg bombs were used.
Remarkable was the first scramble of the bomber squadron from Schiphol in the first hour of the German invasion. All bombers scrambled without bombs and with the assignment to assault the Luftwaffe strike planes. Quite a number of bombers and transporters were shot down against zero own losses (although one plane landed in Zeeland and got heavily damaged during landing on a barricaded runway). Especially the 20 mm gun proved a valuable weapon during these confrontations.
T-IX
Fokker had another dedicated bomber in development, when the war broke out. The prototype was ready and parked in one of the Fokker hangars on Schiphol AFB. It fell into German hands.
The T-IX bomber was an all aluminium plane and resembled the Handley Page Hampden HP.52. In fact it could be a derived design, since this British prototype first flew in 1936 and the Fokker T-IX only in 1939. The specific shape of the T-IX was also produced (design-wise) as a G-1 variant, generally designated as Model 154, later baptised GC-2. The Dutch airforce had shown interest in the GC-2, but war came too early for that model too.
The T-IX prototype had been ordered by the Dutch Minister of Colonies. It was envisaged to replace the standard bomber of the NEI airforce, the Glenn Martin Mod. 139 [American designation B-10].
There is little known about this design. It had flown a series of test flights before the invasion. It was fitted with two very powerful Bristol Hercules II engines of 1,375 hp each. These powerplants must have given the T-IX a top speed (without payload) of around 500 km/hr. Probably the BH II engines were not available for production though. The prototype was parked at the Fokker factory at Schiphol AFB when the invasion occured. It was damaged and later scrapped by the Germans.
Specifications T-V
| Type: | Bomber | |
| Manufacturer: | Fokker [Netherlands] | |
| Crew: | 5 | |
| In service: | 1938 - 1940 | |
| Number in service: | 16 [9 operational, 7 in repair or modification] | |
| Size: | Width: 21 m Length: 16 m Height: 5 m |
|
| Engines: | 2 off Bristol Pegasus XXVI, 915 hp | |
| Max. Speed: | 417 km/hr at 9,200 feet | |
| Weight: | 7,250 kg [fully loaded] 4,700 kg [empty] |
|
| Ceiling: | 8,100 m [max.] 7,500 [practical ceiling] |
|
| Max. range: | 1,550 km | |
| Armament: |
max 1,200 kg bombs of 50, 100, 200 or 300 kg |
|
