P.Hare Royal Aircraft Factory (Putnam)

R.E.7

   Strictly speaking there was no prototype for the R.E.7, although the modified form of the R.E.5, with extensions to the upper wing, can possibly be regarded as having fulfilled that role. In fact, the design was briefly known as the R.E.5a before being redesignated R.E.7. The broad span of its wings endowed it with weight-lifting abilities which caused it to be regarded as worthy of volume production, and 233 were eventually ordered from various subcontractors.
   As in the R.E.5, the forward fuselage was of steel tube, becoming a more conventional wire-braced wooden structure aft of the rear cockpit. The oleo undercarriage, which had a small buffer nosewheel, was similar to that of the early F.E.2b, and the airbrakes which had been tested on the R.E.5 were included, with the aim of reducing the landing run. The 120hp Beardmore engine, a licence-built Austro-Daimler, was again adopted, together with the concealed radiator previously designed for use in the R.E.5.
   The production R.E.7 differed from the modified R.E.5 in several ways, being fitted with a new tailplane of higher aspect ratio and having a revised wing structure which eliminated the centre-section, the upper wing panels meeting above the fuselage centreline, where they were supported by inverted-vee cabane struts.1 The wingtip shape was modified to a semicircular planform, rather than the elliptical shape of the earlier design. The interplane struts were of a broad streamlined shape, their ends tapered in accordance with a formula established by W H Barling and H A Webb which eventually became standardised for strut design.
   A mounting was provided beneath the cockpits to carry the 336lb bomb, which had itself been designed at the Factory, but, as was common at the time, no provision was made for any other armament.
   Delivery of completed machines began in July 1915 and, following flight testing, the first example reached a front-line squadron in France by late the following September.
   The R.E.7's service career was destined to be brief and undistinguished. Not only was the observer in the front cockpit, surrounded by struts and wires, unable to operate any effective armament, but the type was very seriously underpowered. Engineers at the Royal Aircraft Factory announced on 21 January 1916 that an increase in power of approximately five per cent could be obtained by the removal of the silencers and the substitution of stub exhausts. While this was useful when considered as pure research, it did little to improve the performance of the R.E.7, and the War Office was, quite understandably, unimpressed.
   By March, Trenchard considered the R.E.7 to be so outclassed as to be 'useless', and he requested its immediate replacement. At that time, however, there was simply nothing better available, although the following month saw the first delivery of machines powered by the 140hp R.A.F.4a engine, copying an experimental installation made in the R.E.5 the previous summer. This engine, being both slightly more powerful and lighter than the Beardmore, gave a marked improvement in climb, although the top speed was little better. Difficulties with lubrication in the early production engines limited their reliability, and the aeroplanes thus powered soon met with Trenchard's disapproval, for they were still woefully underpowered. However, as was often the case at that stage in the war, the RFC simply had to accept whatever was available, and await the arrival of new types which had been designed in full knowledge of the needs of war.
   Nevertheless, the Farnborough staff laboured on, making experimental installations of a number of alternative power units including the R. A.F.3a and the Rolls-Royce Falcon and Eagle. As with the F.E.2 series, only a massive increase in power could bring about any real improvement in performance, and the few engines capable of providing such power were needed for newer designs.
   The R.E.7's lack of effective defensive armament, which was as great a handicap as its poor performance, was rather more easily resolved. A number of them had a third cockpit, complete with a Nieuport gun ring, installed behind the pilot. The first of these three-seaters, 2348, was completed and ready for trials by 26 September 1916, and had a 160hp Beardmore engine in lieu of the 120hp unit previously installed. Another benefited from the provision of a Rolls-Royce Eagle, and proved quite useful before it was written off in a crash on 31 January 1917.
   Despite these various improvements the R.E.7 was still not really suitable for front-line service, and its withdrawal began in mid-1916, although it served with training establishments virtually until the end of the war.
   A role in which the type finally found a niche was that of target tug, it being one of the first machines employed for this purpose, towing a cloth sleeve against which trainee aircrew could practise aerial gunnery.

   Powerplant:
   120hp Beardmore; 140hp R.A.F.4a V-12;
   250hp Rolls-Royce Eagle V-12
   Dimensions:
   span
   57ft 2in (upper);
   42ft 0in (lower);
   chord 6ft 0in;
   gap 6ft 6in;
   wing area 548 sq ft;
   stagger 3in (11in with Rolls-Royce Eagle);
   length 31ft 10 ? in;
   height 12ft 7in.
   Weights
   (Beardmore): 2,170lb (empty); 3,290lb (loaded)
   (R.A.F.4a): 2,140lb (empty); 3,349lb (loaded)
   (R.R. Eagle): 2,702lb (empty); 4,109lb (loaded)
   Performance (Beardmore):
   max speed 82mph at sea level;
   ceiling 6,500ft;
   climb 30 1/2min to 5,000ft.

O.Tapper Armstrong Whitworth Aircraft since 1913 (Putnam)

The R.E.7

   It was in 1917 that the Siddeley Deasy Motor Car Company in Coventry received its first contract to build aeroplanes, the order being for one hundred R.E.7 biplanes. The R.E. series of aircraft was developed by the Royal Aircraft Factory at Farnborough to fill the need for an aircraft to work in co-operation with the army, the initials R.E. standing for reconnaissance experimental. Some measure of automatic stability was considered to be an essential requirement for this particular duty, and T. E. Busk, at the Factory, had spent much of his short career developing this characteristic in the early B.E. and R.E. aircraft.
   The R.E.7, which appeared in 1915, was a large biplane with two-bay wings and with the top plane extensions braced by outward-sloping struts. A variety of engines were fined to the R.E.7, but most production aircraft had either the 160 hp Beardmore or the 150 hp RAF 4a. This latter engine was already being built by Siddeley Deasy in Coventry and, logically, was the powerplant selected for the R.E. 7s built by the company. Structurally, the R.E.7 was of interest by reason of the fact that steel tubing was used in fabricating the forward part of the fuselage; otherwise the method of construction was conventional except for the undercarriage, an elaborate affair with oleo shock-absorbers and a small wheel projecting in front of the propeller instead of the more usual skid.
   Because of its large wing area, the R. E.7 was a good weight lifter and it was, in consequence, used principally as a bomber carrying the big 336-lb bomb designed by the Royal Aircraft Factory. During its brief operational career, the R.E.7 dropped a number of these bombs with good effect during 1916.
   The R.E.7s built by Siddeley Deasy carried the serial numbers 2348 to 2447. The first to be built, 2348, was initially fitted with the RAF 4a engine, but this was later replaced by the 160 hp Beardmore; at the same time the aircraft was experimentally modified into a three-seater.

Span upper: 57 ft 0 in (17.37m)
Span lower: 42 ft 0 in (12.80m)
Length: 31 ft 11 in (9.73m)
Height: 12 ft 7 in (3.84m)
Wing area: 548 sq ft (50.91 sq m)
All-up weight: 3,450 lb (1,565 kg)

F.Manson British Bomber Since 1914 (Putnam)

The R.E.7

   RE.5s continued in limited operational service until the autumn of 1915, by which time most of the survivors from the original batch of 25 aircraft were being relegated to training duties. A new version, the R.E.7, was coming into service, an aircraft that retained the big Beardmore engine and took no significant account of performance advances made by other in-service aircraft since the beginning of the War.
   However, stemming largely from prewar work done to determine the bomb-carrying potential of the R.E.5, already referred to, the R.E.7 was intended from the outset to carry a single 336 lb bomb, designed and developed at the Royal Aircraft Factory. This bomb, which was first flown experimentally on an R.E.5A, was 4ft 11 1/2in long, and was classified as a heavy case (HC) weapon, containing only 70 lb of compressed or cast TNT.
   Unlike the R.E.5, all R.E.7s were contract-built by commercial manufacturers, namely the Austin Car Company, the Coventry Ordnance Works, D Napier & Sons and the Siddeley-Deasey Motor Car Company, a total of 252 being built. The aircraft featured the long-span upper wings of the R.E.5A, and first reached No 21 Squadron in July 1915, then forming at Netheravon. In September that year No 12 Squadron, already flying B.E.2Cs and R.E.5s at Natheravon, received in addition a few R.E.7s and moved to St Omer on the 6th.
   Owing to delays in manufacturing the Factory's 336 lb bomb, No 12 Squadron's R.E.7s were flown as escort fighters but, with the observer/gunner occupying the front cockpit beneath the upper wing, were quickly found to be quite unable to counter the new German Fokker monoplane scouts, then in full cry over the Western Front.
   When No 21 Squadron brought its full complement of R.E.7s to France in January 1916, both it and No 12 were transferred to special reconnaissance work in preparation for the major Allied offensive which was to be launched on the Somme in July that year.
   As No 12 Squadron gave up its R.E.7s to re-equip with F.E.2Bs, No 21 received new R.E.7s powered by the 150hp R.A.F. 4A - an engine that was some 100 lb lighter than the Beardmore - and in June began operations with the 336 lb bomb, flying from Fienvillers. During the period between 30 June and 9 July the Squadron flew 29 bombing sorties, each with the big bomb, against targets at St Sauveur, Bapaume and Cambrai, often with spectacular results. On at least two other occasions the R.E.7s each carried two 112 lb and six 60 lb bombs.
   Despite these belated successes the bombing career of the R.E.7 was destined to be shortlived, and in August No 21 Squadron, the only operational unit to be fully equipped with the type, was withdrawn from operations to re-equip with the B.E.12. The great majority of R.E.7s were retained at home for training purposes. Some attempts were made to improve their performance, and among the engines experimentally fitted for this purpose were the 190hp Rolls-Royce Falcon and the 250hp Rolls-Royce III. Two aircraft, Nos 2299 and 2348 (built by Napier and Siddeley-Deasey respectively) were modified as three-seaters, with an extra cockpit with Lewis gun mounting added aft of the pilot in an effort to improve the aircraft's ability to defend itself. Predictably the extra weight of gun and gunner only served to reduce the aircraft's very poor performance yet further.
   The truth had yet to dawn on the War Office in early 1916 that engines of greatly improved power/weight ratios were essential if bomb loads of effective powers of destruction were to be carried by aircraft with the slightest chance of survival in the face of superior enemy fighters.

   Type: Single-engine, two-seat, two-bay biplane corps reconnaissance bomber.
   Manufacturers: The Austin Motor Co (1914) Ltd, Northfield, Birmingham; The Coventry Ordnance Works Ltd, Coventry; D Napier & Sons Ltd, Acton, London; The Siddeley-Deasy Motor Car Co Ltd, Park Side, Coventry.
   Powerplant: One 120hp Beardmore; 160hp Beardmore; 150hp R.A.F. 4A. Experimental installations: 190hp Rolls-Royce Falcon; 250hp Rolls-Royce Mk III (284hp Eagle III); 200hp R.A.F.3A; 225hp Sunbeam.
   Dimensions: Span, 57ft 2in; length 31ft 10 1/2in; height, 12ft 7in; wing area, 548 sq ft.
   Weights: 160hp Beardmore. Tare, 2,285 lb; all-up, 3,290 lb. 150hp RAF.4A (with 336 lb bomb). Tare, 2,170 lb; all-up, 3,449 lb. 190hp Falcon. All-up, 3,280 lb.
   Performance: 160hp Beardmore. Max speed, 91 mph at sea level, 83 mph at 10,000ft; climb to 10,000ft, 31 min 50 sec. 150hp R.A.F.4A (with 336 lb bomb). Max speed, 85 mph at sea level. Service ceiling, 6,500ft. Endurance, 6 min.
   Armament: Standard aircraft were provided with a single 0.303in Lewis machine gun on the front cockpit. Capable of carrying one 336 lb R.A.F. bomb, or two 112 lb and four 20 lb bombs.
   Prototype: None. First production aircraft probably first flown in May-June 1915.
   Production: A total of 252 R.E.7s was built: Coventry Ordnance Works, 50 (Nos 2185-2234); Austin, 52 (Nos 2235-2286); Napier, 50 (Nos 2287-2336); Siddeley-Deasy, 100 (Nos 2348-2447). Nos 2241, 2242, 2260 and 2364 were transferred to the RNAS.
   Summary of Service: R.E.7s served with Nos 12 and 21 Squadrons, RFC, over the Western Front during 1915-16, and with Nos 6,9,19, 37, 38, 49 and 60 Squadron, RFC, in the United Kingdom between 1915 and 1917.

P.Lewis British Bomber since 1914 (Putnam)

Among the designs to make their debut at the Factory during 1915 was the R.E.7, a two-seat development of the R.E.5, which was evolved into a fairly useful bomber for the R.F.C. despite an ungainly, unprepossessing appearance. The deep fuselage housed a 120 h.p. Beardmore in the nose, and the unequal-span, two-bay wings were slightly staggered. Ailerons were mounted in the upper wingtips, the overhang of which was braced by a pair of parallel struts. In the absence of a centre-section, the upper wing panels met at the centre-line at the apices of the centre-section struts. The relatively short moment arm dictated the provision of tail surfaces of large area. The R.E.7 was mounted on oleo main legs preceded by a small nosewheel set well to the fore. Basically the machine utilized a conventional wooden frame with fabric covering; the fuselage, however, was formed from steel tubing in the front matched to a wooden structure to the rear of the cockpits. Another unusual feature for an aircraft of the period was the inclusion on a number of R.E.7s of airbrakes in the form of panels hinged vertically to the fuselage sides a little to the rear of the engine.
   The R.E.7 was introduced at a time when the importance of adequate defensive armament was just being appreciated. In spite of this, the observer was placed in the front cockpit, where it was well-nigh impossible for him to wield his Lewis machine-gun with any effect. This drawback was eliminated in the small number of R.E.7s which were converted to contain a third cockpit, to the rear of the pilot, which was surmounted by a Nieuport ring-mount for a single Lewis gun. Several alternative engines were installed in the R.E.7, and the machine was able to carry either a single R.A.F. 336 lb. bomb or two 112 lb. bombs, supplemented by a quantity of 20 lb. bombs. Superseded comparatively soon by aircraft endowed with superior qualities, the R.E.7 was flown on the Western Front for some seven months, chiefly by No. 21 Squadron, R.F.C., the sole unit to be equipped with the machine and which had arrived in France on 23rd August, 1916.

J.Bruce British Aeroplanes 1914-1918 (Putnam)

R.E.7

  THE R.E.7, which appeared in 1915, was developed from the R.E.5 and was intended to carry greater loads. It was a large two-bay biplane with long strut-braced extensions on the upper wings. An unusual feature of the wing cellule was the absence of any conventional upper centre-section: there was a central cabane of inverted vee struts after the fashion of several contemporary enemy types.
  Structurally the R.E.7 was distinguished by a fuselage of composite construction. The portion aft of the cockpits was a conventional cross-braced wooden box girder; but the forward portion was made of steel tubing. The original engine was the 120 h.p. Beardmore, cowled in a manner reminiscent of the R.E.5 and with a similar exhaust manifold and silencer. The undercarriage was the sturdy oleo structure with small nose-wheel which had been used on the F.E.2a and 2b. The tail surfaces were of generous size and characteristic outline.
  Many R.E.7s had air-brakes similar to those which had been tested on an R.E.5: they were attached to the fuselage sides in line with the forward cabane struts, and opened outwards.
  Because it offered the prospect of carrying a useful war-load, the R.E.7 was ordered in considerable quantities from several contractors. Deliveries began late in 1915, and by the end of that year sixteen had been handed over to the R.F.C. The only unit to go to France equipped throughout with R.E.7s was No. 21 Squadron, which arrived there on January 23rd, 1916.
  The R.E.7 thus went into action at the time when the Fokker monoplane was at the zenith of its career, and its earliest duties included escorting the reconnaissance two-seaters over the lines. Since the R.E.7’s observer occupied the forward cockpit, however, he was no more able to use a gun effectively than were his colleagues in the B.E.2c’s, and the R.E.7 was not conspicuously successful as an escort machine.
  Together with No. 12 Squadron, No. 21 was given the duty of performing the special strategical and patrol work required by General Headquarters in the preparations for what was to have been a major Allied offensive, launched in July, 1916. The enemy forestalled this plan by opening an offensive on February 21st, 1916. The Allies’ plans had to be radically altered, and the offensive which was launched on July 1st, 1916, was the beginning of the Battles of the Somme. For their special duties Nos. 12 and 21 Squadrons were based at R.F.C. Headquarters, and provided the basis for the formation of the 9th Wing.
  It was as a bomber that the R.E.7 found its true metier, however. Its ability to lift a comparatively heavy war-load was enhanced by the use of the 150 h.p. R.A.F. 4a and 160 h.p. Beardmore engines; the majority of No. 21 Squadron’s R.E.7s had the former power unit. The installation of the R.A.F. 4a was characterised by the inevitable large air-scoop and funnel exhausts, and was not beautiful.
  The R.E.7 could carry the 336-lb Royal Aircraft Factory bomb. This bomb was carried under the fuselage: its nose was held in a bracket attached to the rear central vee-strut of the undercarriage and its tail by an inverted tripod directly under the pilot’s seat.
  In preparation for the Somme offensive No. 21 Squadron moved to Fienvillers on June 19th, 1916, and on the 30th of that month six of the squadron’s R.E.7s bombed the railway station at St. Sauveur.
  On the following day six machines bombed Bapaume, known to contain a German headquarters, and cut the railway line south of the town. In the afternoon of July 2nd, six R.E.7s again attacked Bapaume: each aircraft dropped a 336-lb bomb, and those which fell on ammunition dumps started fires which could still be seen after nightfall. Cambrai station was the target for the 336-lb bombs of three R.E.7s on July 3rd, and suffered again at 4.30 a.m. on July 9th when six of No. 21 Squadron’s machines attacked with the big R.A.F. bombs.
  At this time No. 21 Squadron had fourteen R.E.7s, four B.E.2c’s and one B.E.2e, but in August, 1916, the squadron was withdrawn to Boisdinghem for re-equipment with B.E.12s.
  The R.E.7’s operational career was comparatively brief and its exploits virtually unknown, but it continued in service for experimental and training purposes until 1918. Other engines were fitted; in some cases the R.E.7 airframe obviously provided no more than a test vehicle. The 190 h.p. Rolls-Royce Falcon, 250 h.p. Rolls-Royce Mk. Ill (Eagle III) and 200 h.p. R.A.F. 3a were all tried, and at least one machine had a 225 h.p. Sunbeam engine.
  The Eagle-powered R.E.7 had a large frontal radiator and a pair of splayed-out funnel exhausts; whilst the R.A.F. 3a had a somewhat makeshift arrangement of radiators and a single central exhaust stack.
  Most remarkable of all the R.E.7s were the three-seat conversions, however. A third cockpit was made immediately behind the pilot’s cockpit, and was fitted with an early Nieuport-type of rotating gun-mounting. At least two R.E.7s were modified in this way: these were No. 2348 and No. 2299. The former had the 160 h.p. Beardmore, but was also flown as a two-seater with the 150 h.p. R.A.F. 4a; the latter was powered by the 250 h.p. Rolls-Royce engine, and had the low-sided front cockpit which appeared on some R.E.7s, particularly those which were not fitted with air-brakes. An R.E.7 with the 250 h.p. Rolls-Royce was used by No. 20 Squadron from the early autumn of 1916 until it crashed on January 31st, 1917. This was probably the R.E.7 three-seater which arrived at No. 2 Aircraft Depot, Candas, on August 20th, 1916.
  Among the last duties of the R.E.7 was the towing of sleeve targets for aerial gunnery practice, and the machine must have been one of the earliest target tugs to be used.


SPECIFICATION
  Manufacturing Contractors: The Austin Motor Co. (1914), Ltd., Northfield, Birmingham; The Coventry Ordnance Works, Ltd., Coventry; D. Napier & Sons, Acton, London, W.; The Siddeley-Deasy Motor Car Co., Ltd., Park Side, Coventry.
  Power: 120 h.p. Beardmore; 160 h.p. Beardmore; 150 h.p. R.A.F. 4a; 190 h.p. Rolls-Royce Falcon; 250 h.p. Rolls-Royce Mk. Ill (284 h.p. Eagle HI); 200 h.p. R.A.F. 3a; 225 h.p. Sunbeam.
  Dimensions: Span: upper 57 ft, lower 42 ft. Length: 31 ft 10 1/2 in. Height: 12 ft 7 in. Chord: 6 ft. Gap: 6 ft 6 in. Stagger: 2-89 in. with Beardmore and R.A.F. 4a engines, 11 in. with Eagle. Dihedral: 2° 30'. Incidence: with Beardmore engines, 3° 06'; with R.A.F. 4a, 4° with 30' wash-out on starboard wing; with Eagle, 3° 06' with 30' wash-out on starboard wing. Span of tail: 16 ft 11 in. Airscrew diameter: R.A.F. 4a, 10 ft; 160 h.p. Beardmore, 9 ft; 250 h.p. Rolls-Royce, 10 ft 3 in.
  Areas: Wings: 548 sq ft. Tailplane: 50 sq ft. Elevators: 32 sq ft. Fin: 13 sq ft. Rudder: 16 sq ft.
  Armament: One 336-lb R.A.F. bomb or two 112-lb bombs augmented by 20-lb bombs. Makeshift arrangements of rifles, pistols or a Lewis machine-gun were used for defence. The three-seater had a Lewis gun on a Nieuport ring-mounting on the rear cockpit, and a second Lewis was provided for the occupant of the front cockpit. There are references to a three-seat R.E.7 with a synchronised Vickers machine-gun for the pilot.
  Service Use: Western Front: No. 21 Squadron, R.F.C., and part of No. 12 Squadron. One three-seat R.E.7 was used by No. 20 Squadron. Training: No. 35 Reserve Squadron, Northolt; School of Aerial Gunnery, Hythe.

  Tankage (in gallons):
160 h.p. Beardmore R.A.F. 4a Eagle
Petrol:
   Main pressure tank - 43 -
   Auxiliary pressure tank - 15 -
   Service tank - 8
   Total 61 66 74
Oil 8 8 1/4 8
Water 6 - 12-6

  Weights (lb) and Performance:
Engine 120 h.p. Beardmore 160 h.p. Beardmore R.A.F. 4a R.A.F. 4a Falcon Eagle
- - With 336-lb bomb Without bomb - -
No. of Trial Report - - M.26 - - -
Date of Trial Report - May, 1916 May, 1916 - - August, 1916
Type of airscrew used on trial - - T.6447 - - T.28023
Weight empty - 2,285 2,170 -. - 2,702
Military load - 160 410 - - 442
Crew - 360 320 - - 360
Fuel and oil - 485 549 - - 605
Loaded - 3,290 3,449 3,139 3,280 4,109
Maximum speed (m.p.h.) at
ground level 82 913 849 84 - -
5,000 ft 73 - - - - -
7,000 ft - - 82 - - -
10,000 ft - 83 - - 86 -
10,120 ft - - - - - 88-2
15,000 ft - - - - 72 -
m. s. m. s. m. s. m. s. m. s. m. s.
Climb to
5,000 ft 30 35 13 25 - - - - - - - -
6,000 ft - - 16 40 29 30 16 30 - - 11 45
6,500 ft - - 18 30 - - - - - - 13 00
9,000 ft - - - - 64 00 - - - - - -
10,000 ft - - 31 50 - - 38 30 24 15 23 30
15,000 ft - - - - - - - - 53 30 - -
Service ceiling (feet) - - 6,500 - - -
Endurance (hours) - - 6 - - -

  Production and Allocation: About 250 R.E.7s were built. A total of 224 were delivered to R.F.C. units: fifty-eight went to France, nineteen to Home Defence Units, and 147 to training stations.
  Serial Numbers: 2185-2234: built by Coventry Ordnance Works. 2236-2265: built by Austin Motor Co. Between and about 2287 and 2300; batch probably built by Napier. 2348-2447: built by Siddeley-Deasy.
  Notes on Individual Machines: 2194: No. 35 Reserve Squadron, Northolt. 2299: three-seater with 250 h.p. Rolls- Royce engine. 2348: three-seater with Beardmore engine; also flown as two-seater with R.A.F.4a.
  Costs:
   Airframe without engine, instruments and guns £1,886
   Engines:
   120 h.p. Beardmore £825
   160 h.p. Beardmore £1.045
   R.A.F.4a £836
   R.A.F.3a £1,210
   250 h.p. Rolls-Royce Mk. Ill £1,430
   190 h.p. Rolls-Royce £1,210

O.Thetford British Naval Aircraft since 1912 (Putnam)

R.E.7

The R.E.7 was a development of the R.E.5, and it first appeared in 1915. It was used mainly by the RFC but six examples were handed over for the use of the RNAS. It was fitted at various times with a great variety of engines, ranging from the 120 hp Beardmore to the 280 hp Rolls-Royce Eagle. Maximum speed with the 120 hp Beardmore was 82 mph. Span, 57 ft. Length, 31 ft 10 1/2 in.

H.King Armament of British Aircraft (Putnam)

R.E.7. Official figures for 'military load plus crew' for three versions of this early 'heavy' bomber give an indication of its load-carrying ability. With the 160-hp Beardmore engine the figure was 520 lb, with the RAF 4a, 730 lb, and with the 250-hp Rolls-Royce, 802 lb. The bomb most generally associated with the type is the RAF 336-pounder, previously mentioned. This was carried with the nose distance-piece in a bracket fixed to the rear V-strut assembly of the undercarriage and with the rear of the characteristic central tube secured by an inverted pylon beneath the fuselage aft of the wings. Nevertheless, the 336-pounder does not appear to have been the heaviest bomb carried by the R.E.7, for a bomb of 500 lb has also been associated with the type, together with the periscopic bombsight developed at the Royal Aircraft Factory. Bombs of 112 lb and 20 lb are also known to have been carried.
   As on the B.E.2c, the observer occupied the front cockpit, and the employment of pistol, rifle or Lewis gun must have been similarly inhibited; but there were remarkable developments in defensive armament. One of these was the addition of a third cockpit behind the pilot, this being provided with a Lewis gun on a Nieuport-type mounting. Another development was the forming of a gunner's station in the top wing above the front cockpit. Oliver Stewart, who personally flew the aircraft concerned for inspection by Gen Trenchard, mentions 'the front gunner standing up in the middle of the centre section with head and shoulders through a large hole'; and with a position of this kind a Scarff ring-mounting has been associated. This is said to have come adrift on one occasion and to have finished up in the pilot's cockpit. An installation of a Lewis gun on the fuselage ahead of the pilot has been positively identified, and mention has also been made of a synchronised Vickers gun.
   The R.E.7 has yet a further interest in the context of armament, for aircraft of the type were among the earliest to tow aerial targets.