F.Manson British Bomber Since 1914 (Putnam)

Bristol Types 24/25 Braemar

   Capt Frank Barnwell, chief designer of the British & Colonial Aeroplane Company, submitted proposals for his B.1 heavy bomber to the War Office late in 1917, in which the performance estimates, based on the use of four 365hp Rolls-Royce Eagles, suggested that it would be capable of reaching Berlin with a small load of bombs. Because the project was not formally prepared to conform to a specific Air Board requirement, Barnwell was informed that Eagle engines would not be made available for the bomber; however, the War Office expressed sufficient interest in the aircraft to issue a contract, signed on 11 December 1917, for three prototypes (C4296-C4298).
   The draft layout was delegated to Wilfrid T Reid for detail design. Nevertheless, despite its imposing bulk, the Bristol bomber was to be much smaller than the Handley Page V/1500. Obliged to use four 230hp Siddeley Puma engines the aircraft, which became the Type 24 Braemar, was probably doomed to obscurity from the outset as it scarcely represented any advance beyond the Handley Page O/400. Moreover, owing to the company's lack of suitable manufacturing space, only one Braemar could be assembled at a time.
   The aircraft was a three-bay, folding biplane with the engines in tandem in fully-cowled nacelles on the centre wing, each engine driving a right-handed two-blade propeller; unlike those of the V/1500, the tractor and pusher propellers were of the same diameter. The two upper wings were of equal span, and the lower slightly shorter, with horn-balanced ailerons fitted to the two upper wings. The fuselage, constructed almost entirely of spruce with wire bracing, was ply-covered except for the nose section. The crew comprised two pilots, a wireless operator, a flight engineer and two gunners (in the nose and amidships). The bomb load, intended to amount to six 250 lb bombs, was carried in an internal fuselage bay. The four-wheel undercarriage featured pairs of tandem wheels, with a braking system, attached to mounting struts anchored to the lower fuselage longerons and the wing spars below the engines, this structure resulting in a very narrow track.
   The first Braemar, C4296, was completed in August 1918 and flown by Fred Raynham on the 13th. The same pilot delivered the aircraft to Martlesham Heath exactly one month later. It was evaluated against the RAF Specification Type VIII which had been issued during its period of design and, with certain reservations, was considered to come close to the requirements, though it did not meet the load and endurance figures by fairly large margins. Some criticism was levelled at the flying controls, the ailerons being particularly heavy, and at the very poor field of vision from the pilots' cockpit. Doubt has been cast on a figure often quoted for this Braemar's maximum speed of 106 mph at a gross weight of 16,200 lb, for the highest corrected speed achieved by the aircraft at Martlesham was 102 mph at a weight of about 13,000 lb. C4296 was taken on RAF charge in May 1919, but was written off in a crash two months later.
   From the outset it was obvious that the first prototype was underpowered and, once C4296 had left the factors, a second aircraft, the Type 25 Braemar II, C4297, powered by four 410hp Liberty 12A engines, was built, making its maiden flight on 18 February 1919. This aeroplane incorporated a number of improvements, including slight alterations to the nose profile to increase the pilots' field of view, and strengthening of wing tie rods; the undercarriage was also improved, though its narrow track remained unchanged. As far as is known the Braemar never carried its full intended bomb load, although in trials at Martlesham in 1919 C4297 recorded a speed of 122 mph at 5,600 feet while loaded with six 112 lb bombs. This aircraft was to be destroved in an accident when, taking off out of wind on 16 August 1921, it swung out of control and struck a building.
   A third Braemar, C4298 (the Mark III), was flown in June 1919 but was almost immediately converted to a passenger-carrying aircraft and renamed the Type 26 Pullman. As such it was evaluated at Martlesham during September and October 1920, but its ultimate fate is not known.

   Type; Four-engine, six-crew, three-bay triplane long-range heavy bomber.
   Air Ministry Specification: RAF Type VIII.
   Manufacturer: The British and Colonial Aeroplane Co Ltd., Filton, Bristol.
   Powerplant: Mark I. Four 230hp Siddeley Puma six-cylinder water-cooled in-line engines, two driving two-blade tractor and two driving pusher propellers, and mounted in tandem in two nacelles mounted on the centre wing. Mark II. Four 410hp Lincoln-built Liberty 12A water-cooled in-line engines.
   Structure: Wire-braced, all-wood structure, the fuselage ply-covered, and the two-spar, folding wings, fabric-covered.
   Dimensions: Span, 81ft 8in; length, 51ft 6in; height, 20ft 8in; wing area, 1,905 sq ft.
   Weights (Mark II): Tare, 10,650 lb; all-up (max bomb load), 18,500 lb.
   Performance (Mark II): Max speed, 125 mph at sea level, 110 mph at 10,000ft; climb to 10,000ft, 17 min 40 sec; absolute ceiling, 17,000ft.
   Armament: Five 0.303in Lewis machine guns: two on nose gunner's cockpit with Scarff ring; two guns with pillar mountings on midships gunner's cockpit; and single gun on Scarff ring in floor of fuselage amidships. Max bomb load, six 230 lb bombs.
   Prototypes: Three: C4296 (Mark I) and C4297 (Mark II); C4296 first flown by F P Raynham at Filton on 13 August 1918. No production. (Third aircraft, C4298, was converted to Bristol Type 26 Pullman commercial passenger aircraft, but not operated as such.)

P.Lewis British Bomber since 1914 (Putnam)

In the course of the closing months of the 1914-18 War a number of new advanced bomber aircraft were under construction as prototypes and were completed soon after the Armistice. In the West Country during October, 1917, Capt. F. S. Barnwell at Bristol spent some time on a scheme for a large triplane bomber with folding wings and a crew of six. The machine was designated B.l and was prepared to possess a minimum range of 1,000 miles to enable it to bomb Berlin. Its capacity was to be such that it would carry internally six bombs of 250 lb. each.
   Technically, the design was of particular interest, as it envisaged the embodiment of a concept which had been considered a number of times previously by other designers, namely the use of a power plant situated in the main fuselage and coupled to wing-mounted propellers. In this case four engines were scheduled for installation in a central engine-room from which gears and shafts would drive a single tractor four-blade propeller on each side of the engine bay. Preoccupation with his fighter design work made it impossible for Barnwell to devote further time to the B.l, so the layout was transferred to W. T. Reid for development. The practicability of the original centralized power-plant scheme was never put to the test by Bristol, as, once on Reid’s drawing-board, considerable revision and simplification took place. The triplane wings were retained, the central planes acting as bearers of a pair of tandem engines on each side. The design was submitted soon to the Air Board, resulting in an order for three prototypes being placed on 26th February, 1918.
   Once the project was accepted, construction of C4296 - the first Type 24 Braemar Mk.I - went ahead rapidly so that a successful initial flight was made by F. P. Raynham on 13th August, 1918. The shortage of 360 h.p. Rolls-Royce Eagle engines for which the four-seat Braemar was designed, meant that substitutes had to be found to fly the machine. Four 230 h.p. Siddeley Pumas were selected, but the total output was considerably lower than that with which the Mk. I was intended to show its paces. Nevertheless, the big 81 ft. 8 in. span triplane performed very creditably in its official trials at Martlesham during September, 1918.
   Sweepback was incorporated in the three-bay wings outboard of the centresection, the cellules being mounted on a conventional fuselage with slab sides. The main undercarriage consisted of four wheels installed beneath the lower wings’ centre-section in tandem pairs. Horn-balanced ailerons were incorporated in the centre and upper planes, and the tail unit used biplane horizontal surfaces and triple fins and rudders.
   The second Braemar to be built, the Type 25 Mk. II C4297, was completed early in the following year, making its maiden flight on 18th February, 1919, with Capt. C. F. Uwins at the controls. The Mk. II, fitted with four Liberty 12 engines giving 400 h.p. each, was able to reach a top speed of 125 m.p.h., nearly 20 m.p.h: faster than the Braemar Mk. I. Consideration was given to converting the Mk. II to carry a torpedo beneath its fuselage, but towards the end of 1921 the machine was written off following an accident at Martlesham prior to taking-off.
   The third Braemar prototype was completed in the spring of 1920, not as a bomber but as the Pullman civil transport with a fuselage accommodating fourteen passengers. In its bomber form the Braemar was scheduled to carry six 230 lb. bombs and to be armed with five Lewis guns.

J.Bruce British Aeroplanes 1914-1918 (Putnam)

Bristol Braemar

  CAPTAIN BARNWELL made his preliminary designs for a large triplane bomber as early as November, 1917, when it was made known that bombing attacks on Berlin were to be carried out from bases in England as soon as aircraft were available which were capable of doing so.
  The original conception was of a large triplane with a fuselage of good aerodynamic form incorporating a central engine room in which four engines were to be installed. Two outboard tractor airscrews were to be driven by shafts and gearing. Internal stowage for six 250-lb bombs was envisaged, and petrol for a range of at least 1,000 miles was to be carried.
  Development of the design was entrusted to W. T. Reid, for Barnwell wished to devote his attention to the two-seat fighter which was to become the Badger. The bomber design was progressively modified, and was considerably different from Barnwell’s original layout by the time a contract for three prototypes was awarded.
  The machine as built was named Braemar, and in order to test the airframe without delay the first prototype was fitted with four 230 h.p. Siddeley Puma engines mounted on the centre mainplane in two back-to-back pairs. The basic structure was of wood with the usual wire bracing. The fuselage was covered with plywood, and not the least remarkable feature of the Braemar was the fact that the wings could be folded. It was much larger than any other aeroplane built at Filton up to that date: its dimensions prevented the assembly of more than one machine at a time. The final assembly had to be carried out in a hangar at the aerodrome, and the first Braemar was completed during the summer of 1918. The test flying was done by F. P. Raynham, and the machine underwent official trials at Martlesham Heath in September, 1918. The official report mentions a certain amount of vibration in the fuselage, and modifications were made to the undercarriage. The second Braemar, C.4297, had the improved undercarriage.
  The second machine was powered by four Liberty 12 engines, and was designated Braemar Mk. II. It did not fly until February 18th, 1919, and arrived too late to be ordered in quantity. Its performance was good, and it might well have proved to be an efficient bomber if the war had lasted longer.
  The Braemar Mk. II was at Martlesham Heath in July, 1919, and apparently remained there until the following year. On test, its fuel system proved to suffer from a defect similar to that of the D.H.10: at low air speeds the wind-driven pumps failed to maintain an adequate supply of fuel.
  The third airframe was not completed as a Braemar but, with a completely re-designed fuselage, emerged in 1920 as the Bristol Pullman, a commercial machine which provided enclosed accommodation for fourteen passengers in considerable luxury.


SPECIFICATION
  Manufacturers: The British & Colonial Aeroplane Co., Ltd., Filton, Bristol.
  Power: Braemar Mk. I: four 230 h.p. Siddeley Puma. Engine Nos.: port front 6406.24080; port rear 6394.24068; starboard front 6399.24073; starboard rear 6368.24042. Braemar Mk. II: four 400 h.p. Liberty 12 (built by the Lincoln Motor Co.). Engine Nos.: port front 18020/601, W.D. No. 62068; port rear 18018/609, W.D. No. 62067; starboard front 18022/608, W.D. No. 62069; starboard rear 26172/2768, W.D. No. 65326.
  Dimensions: Span: top and centre 81 ft 8 in., bottom 78 ft 3 in. Length: 51 ft 6 in. Height: 20 ft 8 in. Chord: 8 ft 6 in. Gap: both 7 ft 2 1/2 in. Stagger: nil. Sweepback: 6° 30'. Dihedral: 2°. Incidence: 2° 30'. Airscrew diameter: front, Mk. I 9 ft 10 in.; Mk. II 10 ft; rear, Mk. I 9 ft 2 1/4 in.; Mk. II 9 ft 6 in. Tyres: Mk. I, 900 X 200 mm; Mk. II, 1100 X 220 mm.
  Areas: Wings: top 650 sq ft, middle 650 sq ft, bottom 605 sq ft, total 1,905 sq ft. Ailerons: each 48 sq ft, total 192 sq ft. Tailplanes: upper 51-5 sq ft, lower 45 sq ft, total 96-5 sq ft. Elevators: upper 42-5 sq ft, lower 42-5 sq ft, total 85 sq ft. Fins: two of 11-4 sq ft and one 5-2 sq ft, total 28 sq ft. Rudders: two of 7-6 sq ft and one 10-2 sq ft, total 25-4 sq ft.
Weights (lb) and Performance:
Braemar Mk. I Braemar Mk. I Braemar Mk. II
With 6 X 112-lb bombs With 5,000 lb load With 2,500 lb load
No. of Trial Report M.233a M.233a M.271c
Date of Trial Report September to September to February nth,
October, 1918 October, 1918 1920
Type of airscrew used on trial:
front P.3060 P.3060 A.B.22699
rear P.3065 P.3065 P.3084
Weight empty 9.578 9.578 11,208
Military load 345 305 828
Crew 720 540 680
Fuel and oil 3.635 1.355 3.496
Water 300 300 300
Weight loaded 14.578 12,078 16,512
Maximum speed (m.p.h.) at
5,000 ft 103-5 107 -
5,650 ft - - 122
6,500 ft 101 105-5 -
10,000 ft 95 101-5 -
13,000 ft - 98-5 -
14,400 ft - - 107-5
m. s. m. s. m. s.
Climb to
1,000 ft 1 50 1 20 1 00
2,000 ft 3 55 2 45 2 05
3,000 ft 6 10 4 15 3 15
4,000 ft 8 35 5 55 4 30
5,000 ft 11 15 7 35 5 55
6,000 ft 14 10 9 30 7 25
7,000 ft 17 35 11 35 9 00
8,000 ft 21 25 13 50 10 50
9,000 ft 26 05 16 25 12 50
10,000 ft 31 40 19 15 15 05
11,000 ft 38 50 22 30 17 40
12,000 ft - - 26 20 20 50
13,000 ft - - 30 50 24 30
14,000 ft - - - - 29 25
15,000 ft - - - - 36 20
Absolute ceiling (feet) 14,000 17.500 17,000

  Tankage: Braemar Mk. I. Petrol: four main tanks in fuselage: two port tanks of 107 gallons each, starboard front tank 103 gallons, starboard rear tank 105 gallons; two gravity tanks of 14 gallons each in top wing; total 450 gallons. Oil: four tanks, two between each pair of engines, 11 gallons in each; total 44 gallons. Water: 30 gallons. Braemar Mk. II. Petrol: four main tanks in fuselage, each of 105 gallons; two gravity tanks, each of 14 gallons, in top wing; total 448 gallons. Oil: four tanks, total 41 1/2 gallons. Water: 30 gallons.
  Armament: Racks for six 230-lb bombs were provided, and up to five Lewis machine-guns could be carried as follows: two on Scarff ring-mounting on nose cockpit, two on rocking-post mountings in dorsal cockpit aft of wings, one on Scarff ring-mounting on floor of fuselage aft of wings.
  Production: Two Braemars were built, one Mk. I and one Mk. II. The third airframe was completed as the Bristol Pullman.
  Serial Numbers: C.4296-C.4298: ordered under Contract No. A.S.38907. C.4296: Braemar Mk. I; C.4297: Braemar Mk. II; C.4298: completed as Bristol Pullman.

H.King Armament of British Aircraft (Putnam)

Braemar. The Braemar four-engined triplane bomber of 1918/19 had internal cells for six 230 250-lb or twelve 112-lb - five 40-lb bombs, aimed from the nose by the front gunner, who had a Scarff ring-mounting for twin Lewis guns. For these there were six ammunition drums. Doubtless dictated by the width of the fuselage was the fitting in the dorsal position of two transversely-moving pillar mountings for one Lewis gun each. (Later large bombers, as will be seen, had laterally-sliding Scarff ring-mountings.) For this second station there were six ammunition drums. There was, additionally, a ventral position with an inverted-bow mounting for a fifth Lewis gun, and for this there were eight drums, four on each side, disposed horizontally. As the Braemar was intended for the bombing of Berlin, it is probable that the carrying of a single 3.300-lb bomb was in view, and certainly a scheme was prepared late in 1921 for fitting a torpedo-carrier under the fuselage. This installation would have placed the Braemar in the category of the Blackburn Cubaroo and Avro Ava.
   A point of special note is that one contemporary document mentioned a gyro bombsight. This was said to be mounted to the rear of the pilot's seat, together with other instruments 'for bomb dropping'. In the forward compartment was a High Altitude sight.

A.Jackson British Civil Aircraft since 1919 vol.1 (Putnam)

BRISTOL TYPE 26 PULLMAN TRIPLANE

   After the 1918 Armistice the unfinished airframe of the third Bristol Braemar four-engined heavy bomber was completed as the Pullman Triplane with cabin accommodation for two crew and 14 passengers. One aircraft only: C4298, c/n 3753, powered by four 400-h.p. Liberty engines, allotted the civil registration G-EASP for one month from 14.4.20. Type number 26 allotted in 1923. Span, 81 ft. 8 in. Length, 52 ft. Tare wt., 11,000 lb. A.U.W., 17,750 lb. Max. speed, 135 m.p.h. Cruise, 100 m.p.h.

Jane's All The World Aircraft 1919

The Bristol " Braemar " was originally designed as a long, distance bomber, but owing to the Armistice coming when it did the machine was never used on active service. It is now being slightly modified to do duty as a passenger-carrier and commercial machine.
   It is a four-engined triplane with a single fuselage and with the four engines fixed in pairs tandem-wise driving two tractors and two pushers on either side of the fuselage.
   In its original form the fuselage had accommodation for one gunner in the nose, two pilots just in advance of the main planes and another gunner's cockpit midway between the planes and the tail unit. The tail is a biplane with triple rudders.
   The main planes are slightly swept hack and ailerons are fitted to the two upper planes only.
   The main planes are made to fold.
  
  
  
Specification.
Type of machine Four-engined Triplane.
Name or type No. of machine Braemar Mk. 2.
Purpose for which intended Bomber or Passenger Carrier.
Span Top 81 ft. 8 in.,
   centre 81 ft. 8 in.,
   bottom 78 ft. 3 in.
Gap 7 ft. 2 1/2 in.
Overall length 51 ft. 6 in.
Maximum height 20 ft.8 in.
Chord 8 ft. 6 In.
Total surface of wings 1,905 sq. ft.
Total area of tail Top 51.5 sq. ft.,
   bottom 45 sq. ft.
Area of elevators Top 42.5 sq. ft.
   bottom 42.5 sq. ft.
Area of rudder 25 sq. ft.
Area of fin 28.2 sq. ft.
Engine type and h.p. Four Liberty engines, 1,640 h.p. (total).
Airscrew, diam., pitch and revs. Front (two) 10 ft. 2 In. dia.,
   rear (two) 9 ft. 2 in. dia.,
   front (two) 6 ft. 11 in. pitch.
   rear (two) 7 ft. 5 in. pitch,
   1,750 r.p.m.
Weight of machine empty 10,650 lbs.
Load per sq. ft. 8.6 lbs.
Weight per h.p. 10 lbs.
Petrol tank capacity in gallons 450 gallons.
Oil tank capacity in gallons 40 gallons.
Performance.
   Speed low down 125 m.p.h,
   Speed at 5,000 feet 122 m.p.h.
   Speed at 10,000 feet 113 m.p.h.
   Landing speed 55 m.p.h.
   Climb.
   To 5,000 feet 6 minutes.
   To 10,000 feet 13 minutes.
Disposable load apart from fuel 1,940 lbs
Total weight of machine loaded 16,500 lbs

Журнал Flight

Flight, January 23, 1919.

"MILESTONES"

The Bristol Triplane.

While for her largest machines Italy has to a great extent pinned her faith in the triplane, as instanced by the large Caproni triplane bombers, there has been in this country a tendency, rightly or wrongly, to adhere to the biplane type, even for very large machines. That excellent results may be obtained by the biplane form has been amply demonstrated by the large four engined Handley Pages, but it may be doubted whether the triplane form has been as extensively tested as it deserves. The object of the Bristol Bomber was to provide a high-speed machine for bombing or passenger carrying, capable of lifting a considerable load in addition to the weight of crew and fuel. The "Braemar," as the Bristol Bomber is called, is driven by four Siddeley-Deasy "Puma" engines, developing a total of 1,000 h.p. at 1,500 ft. The manner of mounting the engines will be clear from the illustrations. Two drive tractors while the other two drive pushers, after the manner of the large Handley Page. The two tractors have a diameter of 9 ft. 10 in. and a mean pitch of 6 ft. 11 in., while the diameter of the pushers is 9 ft. 2 in., and the pitch 7 ft. 2 1/2 in. The two pilots' seats are placed side by side in the fore part of the body, some distance ahead of the leading edge of the planes, while the extreme nose of the fuselage is occupied by a gunner. Well aft in the body is another cockpit with two guns mounted on a turntable, while a fourth gun is mounted on another gun ring in the floor of the fuselage. The machine is thus well capable of looking after herself as regards defensive gun arrangements. The weight of the machine empty is 9,300 lbs., and she carries 400 gallons of petrol, 40 of oil, and 30 gallons of water. After allowing 360 lbs. for two pilots, the machine is still capable of lifting another 3,000 lbs., bringing the total loaded weight up to 16,200 lbs. The wing loading, it will be seen, is fairly high, 8 1/2 lbs. per sq. ft., and the load per horse-power is 16.2 lbs. The speed at ground level is 106 m.p.h., which is not bad for such a large machine, and the climb to 10,000 ft. only takes 35 minutes. Naturally the performance cannot compare with that of the smaller machines, but for a weight lifter it is not by any means poor, and the machine might make a good commercial aeroplane for carrying large loads.

  
  
Flight, December 18, 1919.

THE PARIS AERO SHOW 1919

PRELIMINARY REPORT ON BRITISH SECTION

The British and Colonial Aeroplane Co., Ltd.

   From the very first days of flying and of aero shows, the British and Colonial Aeroplane Co., of Filton, Bristol, have made it a rule to exhibit at the Paris Aero Salons. With the excellent workmanship for which Bristol machines were ever famous, it is not too much to say that this firm's stand has always been one of the attractions of the show, and on more than one occasion the Bristols have been the only British machines to be exhibited. This year, as usual, the Bristols are to be shown in Paris, and although the representation of Britain is not left solely to this firm, their stand will, nevertheless, be a conspicuous one, no less than three complete machines being shown, while a fourth, the Bristol Pullman, is so large as to prevent the actual machine from being exhibited. An excellent scale model of it will, however, be on view, and should, in conjunction with illustrations, enable visitors to form a very good picture of the luxurious "Pullman."
<...>

The Bristol "Pullman"

   As already mentioned, there will be exhibited on the Bristol stand a very fine scale-model of the Bristol "Pullman." This large triplane is provided with a most luxurious cabin, seating 14 passengers, who obtain an excellent view of the country over which the machine is passing, through Triplex windows in the side. One of our photographs gives a very good idea of the comfort and spaciousness of the cabin, which has a height of 7 ft., and is heated and lighted by electricity.
   Fitted with four 410 h.p. Liberty engines, placed on the wings, the machine is capable of a maximum speed of 125 m.p.h., while the economical speed is 100 to 105 m.p.h. In addition to the two pilots (or pilot and engineer) the Pullman has a lifting capacity of 2,700 lbs., with a fuel capacity of five hours' flight, or 4,000 lbs. with fuel for two and a half hours' flight. These figures are based on an economical speed of 100 to 105 m.p.h., i.e. at three-quarter throttle, giving a sufficient reserve of power to reach a maximum speed of 125 m.p.h. if necessary. If desired, the seats may be removed and the machine used for carrying mails and cargo, the space available being then 570 cub. ft. The machine has an overall length of 52 ft. and a wing span of 81 ft. 8 ins. The weight empty is 11,000 lbs., and fully loaded 17,750 lbs. Climb to 5,000 ft. in 5 mins., and to 10,000 ft in 12 mins. The ceiling is about 15,000 ft. with full load.