Airco DH.5

https://en.wikipedia.org/wiki/Airco_DH.5

The Airco DH.5 was a British First World War single-seat biplane fighter
aircraft. It was designed and manufactured at British aviation company Airco.
Development was led by the aircraft designer Geoffrey de Havilland as a
replacement for the obsolete Airco DH.2.

The DH.5 was one of the first British fighter designs to include the improved
Constantinesco gun synchronizer, which allowed a forward-firing machine gun to
fire through the propeller faster and more reliably than the older mechanical
gears. It was also one of the earliest biplanes to feature a marked
"back-stagger" of its wings. Despite these advances, by the time the DH.5 was
fielded, it was already notedly inferior to other fighters that had entered into
production and thus proved to be both unpopular and unsatisfactory amongst the
pilots of the Royal Flying Corps (RFC). As such, the type was quickly withdrawn
from service as soon as supplies of the Royal Aircraft Factory S.E.5 permitted.

Shortly after completing work upon the twin-seat Airco DH.4 light bomber,
Captain Geoffrey de Havilland commenced work on a new single-seat fighter
aircraft to replace the obsolete Airco DH.2 fighter, which was designated at the
DH.5. The design sought to combine the superior performance of a tractor biplane
with the excellent forward visibility of a pusher type. The resultant aircraft
was a relatively compact single-bay biplane, while the construction was that of
a conventional tractor biplane, the mainplanes were given 27 inches of backward
stagger, so that the lower wing was positioned forward of the upper wing. This
configuration enabled the pilot to be positioned underneath the leading edge of
the wing, providing uninterrupted forward and upward views; aviation author J.M
Bruce refers to this approach as having been radical for the era.

The first prototype emerged during late 1916, and underwent manufacturer's
trials at Hendon Aerodrome in the hands of test pilot B.C. Hucks. It was powered
by a single Le Rhône 9Ja rotary engine, capable of providing up to 110hp of
thrust, which drove a twin-bladed propeller. The fuselage had flat sides aft of
the wings and featured relatively short fairings either wise of the circulare
engine cowling; towards the rear of the airframe, the fuselage tapered to the
tail, which comprised a small fin and horn-balanced rudder arrangement. The
equal-span single-bay wings were outfitted with atypically large ailerons on
both the upper and lower mainplanes, a rubber bungee cord attached to the upper
ailerons to return them to their standard position. At one early stage, it was
known that the prototype was outfitted with a small hemipherical spinner. As the
pilot was seated forward of the centre of gravity, the main fuel tank was
necessarily behind the cockpit, below the oil tank. An auxiliary gravity fuel
tank was fitted over the top mainplane, offset to the right.

Initial test flights with the prototype detirmined that it lacked sufficient
directional control, a finding which led to a revised and enlarged fin and
rudder combination being adopted. Early on, the first prototype had been flown
in an unarmed state. Around the same time as the revised tail unit was
installed, it was also decided to arm the aircraft in preparation for official
trials. Upon being armed, the prototype armament installation comprised a single
forward-firing .303 in (7.7 mm) Vickers machine gun, which was either fixed to
fire upward at an angle or possibly mounted so that its elevation could be
adjusted in flight; in the production installation the gun was given a more
conventional fixed mounting on top of the cowl, offset to the left, to fire in
the line of flight. Bruce notes that it appeared that the DH.5 was designed with
the intention of typically attacking enemy planes from below, a decision that he
described as iroic considering its limited operational celing in comparison to
its contemporaries.

On 9 December 1916, the first DH.5 prototype commenced its service trials at the
Central Flying School. The official report compiled from the observations of its
pilots was largely favourable, stating that it possessed staisfactory stability
and controllability, its favourable quailities for reconnaissance and agility,
but also observed a poor view to the rear. The type's speed was a significant
advance over its DH.2 predercessor, but it was also recognised that some
existing fighters were already capable of exceeding its capabilities, especially
its climbing abilities. It has been speculated that performance may have been
negatively impacted via the adoption of an alternative four-bladed propeller
during testing.


Role
fighter

Manufacturer
Aircraft Manufacturing Company (Airco)

Designer
Geoffrey de Havilland

First flight
August 1916

Introduction
May 1917

Primary user
Royal Flying Corps (RFC)

Number built
550

The introduction of the DH.5 to squadron service with the Royal Flying Corps
(RFC) was protracted; according to Bruce, these delays, which had been mainly
generated as a result of Airco's focus having been centered upon the more
successful DH.4, had greatly hindered the type's prospects. On 1 May 1917, the
first DH.5 arrived with No. 24 Squadron of the RFC; deliveries were slow, as the
squadron had only a handful of the type by 7 June. The DH.5 was not well
regarded by the squadron, and this negative attitude would not be a unique
outlook.

Soon after entering service, the DH.5 quickly proved to be most unpopular
amongst the RFC. Its unconventional appearance led to rumours (that were largely
unfounded) of handling difficulties. There were also claims that the DH.5 had
gone into service against the wishes of its designers. What was true was that
the DH.5's performance would rapidly drop off at altitudes in excess of 10,000
ft (3,000 m) and that while it was very manoeuvrable, it tended to lose altitude
quickly in combat. The unusual position of the upper mainplane resulted in an
unfortunate blind spot above and to the rear (which was the very direction from
which a single-seater would generally be attacked from).

The robust construction, good performance at low altitude and the pilot's good
forward field of view made the aircraft a useful ground-attack aircraft. In this
capacity, the type served with distinction in the Battle of Cambrai. During the
battle, the DH.5 had, in conjunction with Sopwith Camels, provided airborne
mobile machingun coverage to friendly troops on the ground, strafing enemy
trenches and leading to extensive losses. However, the process of replacing the
type had already commenced beforehand, and the meritorious performance at
Cambrai did little to halt this withdrawal.

The DH.5 has the historical distinction of having formed the initial equipment
of No. 2 Squadron Australian Flying Corps, the first Australian fighter
squadron. It did not prove satisfactory, incidents in which enemy twin-seater
planes were able to escape the single-seat DH.5 were not uncommon. It served
mainly in the ground-attack role until December 1917, when the type was replaced
by the S.E.5a. By this time, the withdrawal of the type from the Western Front
was already almost complete - the last DH.5 squadron receiving the S.E.5a in
January 1918. DH.5s issued to training units proved unpopular and the type soon
vanished from RFC service. A number of retired aircraft were reused as trials
machines, some of these tests included alternative gun mountings, jettisonable
fuel tanks and plywood coverings.

Specifications

General characteristics
Crew: 1
Length: 22 ft 0 in (6.71 m)
Wingspan: 25 ft 8 in (7.82 m)
Height: 9 ft 1 1/2 in (2.781 m)
Wing area: 212.1 sq ft (19.70 m2)
Empty weight: 1,010 lb (458 kg)
Gross weight: 1,492 lb (677 kg)
Fuel capacity: 26 imp gal (31 US gal; 120 L)
Powerplant: 1 × Le Rhône 9J nine-cylinder rotary engine, 110 hp (82 kW)
Propellers: 2-bladed, 8 ft 6 in (2.59 m) diameter

Performance
Maximum speed: 102 mph (164 km/h, 89 kn) at 10,000 ft (3,050 m)
Endurance: 2 hr 45 min
Service ceiling: 16,000 ft (4,900 m)
Time to altitude:
12 min 25 s to 10,000 ft (3,050 m)
27 min 30 s to 15,000 ft (4,570 m)


Armament

Guns: 1 × 0.303 in (7.7 mm) Vickers machine gun
Bombs: racks for four 25 lb (10 kg) bombs under fuselage



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