W.Green, G.Swanborough The Complete Book of Fighters

SPAD S.XV France

   After Louis Bechereau left SPAD in the spring of 1917, responsibility for subsequent aircraft design devolved upon Andre Herbemont, and the first fighter entirely of his creation was the S.XV, a small single-seater with twin synchronised 7,7-mm Vickers guns, and, initially, a 160 hp Gnome Monosoupape rotary engine. The S.XV had a clean, wooden monocoque fuselage, single-bay wings and a large spinner-like fairing ahead of the propeller (probably similar to the Nieuport cone de penetration). The S.XV first flew on 31 July 1917, and a second version, the S.XV/2 with extended wings, a redesigned tail and a simplified engine installation, followed in August. Neither was a success and some redesign was undertaken, the S.XV/3 with a lengthened fuselage having reportedly flown in January 1918. A fourth version, the S.XV/4, was to have had a 170 hp Le Rhone engine, but appears to have been abandoned by 1 May 1918, the date of an official listing. Two much-modified examples of the S.XV were built after the end of the War with the 80 hp Le Rhone engine as sporting single-seaters. The following data relate to the S.XV/2.

Max speed, 124 mph (199 km/h) at 6,560 ft (2 000 m).
Time to 6,560 ft (2 000 m), 5.67 min.
Endurance, 2.5 hrs.
Empty weight, 811 lb (368 kg).
Loaded weight, 1,378 lb (625 kg).
Span, 23 ft 3 1/2 in (7,10 m).
Length (S.XV), 17 ft 6 5/8 in (5,35 m).
Height, 7 ft 6 1/2 in (2,30 m).
Wing area, 188.4 sq ft (17,50 m2).

C.Owers French Warplanes of WWI. Volume 1: Fighters (A Centennial Perspective on Great War Airplanes 43)

Spad 15

  The Spad 15 has been described under a variety of designations, indeed in one post-war source it is shown as the SPAD 15 and XV1 to XV5 in the same document. The designation 15/1 to 15/5 is used in the following for simplicity and clarity. SPAD was the company’s name and the aircraft were known as Spads.

  In July 1917 the British Air Board was notified that Messrs. Spad are completing an experimental biplane, having 13 1/2 square metres wing surface and which is fitted with a 150 h.p. Gnome Monosoupape engine.
  The fuselage is of circular section built up of three layers of tulip wood applied helically in strips, the inside and outside layers going in one direction and the middle layer crossing them, approximately at right angles, in the other, the whole being finally covered with fabric. Thickness of the skin is 3.5 m/m.
  There are two thin longerons, one at the top and one at the bottom, but no horizontal ribs, vertical formers being used to maintain the planes, undercarriage, engine bearing plate, etc.
  The whole weight of the fuselage complete with metal fittings for the attachment of planes etc., is only 17 kgms.
  “Despite this extraordinary low weight the machine has a factor of safety of 7, and the appearance of a workman and strong piece of work."

  Although Louis Bechereau had left SPAD in the spring of 1917, and the Type 15 was the first fighter that Andre Herbemont was entirely responsible for, the machine still showed Bechereau influences in its detail design. It was designed to meet the requirement for a single-seat medium altitude fighter carrying a 220 kg payload, with a service ceiling of 6,000 metres, capable of reaching 9,000 metres and having a speed of 224 km/h. The proposed motor was to be the 160-hp Gnome 9Nc rotary engine.
  The Spad 15 was a small, very clean and fast looking single-bay biplane, the "streamline effect being obtained by the arrangement of the motor within the radius of the fuselage." The wooden monocoque fuselage was exceptionally clean. The wings were constructed as single pieces, had nearly equal spans and were unstaggered. The leading edge of the wings was covered with ply to the front spar. Silk was used instead of ordinary fabric and was sewn to every rib.
  The tailplane was made in one piece and passed through a slot cut into the fuselage to which it was secured by a metal flange. The undercarriage was similar to the standard Spad but lighter. Two synchronised Vickers machine guns were fitted in the same position as the Spad 13. Provision was made for 600 rounds.
  A large cone de penetration was fitted in front of the airscrew. The large aluminium cone was attached upon a spindle forming an extension of the propeller hub upon which the cone was free to revolve, not being attached to the airscrew, and was fitted with ball bearings for that purpose. This system was adopted for ease of detachment of the cone when changing the airscrew. The same cone could be used with any airscrew and there was no possibility of it being fitted out of line.
  It was thought that provided the fuselage proved satisfactory the machine would be easy to manufacture in large quantities "owing to its simplicity and small number of component parts." Trials were expected "towards the end of the current week." The machine first flew on 31 July 1917.
  Another report noted that the machine was still in an experimental state and "a new cowl is being fitted to obtain the results of tests."
  The US Air Service program to produce Spad aircraft appears to have been initiated on 2 May 1917, when Col V.E. Clark suggested that examples of the 150-hp and 180-hp Spads be acquired with the view of their being manufactured in the USA. On 29 July he recommended the 170-hp Gnome as the single-seat pursuit plane. Two days later he cabled:
  Believe necessary build both best fixed engine fighter and best rotary engine fighter now developed. These are SPAD with 200 hp Hispano, and new SPAD with 150 hp Gnome Monosoupape... Recommend SPAD monocoque with 150-180 Gnome Monosoupape engine and two Vickers machine guns firing through the propellers (sic). Machine now being tested. Believe it best yet, but probably can be flown only by best pilots. ”

  The Bolling Commission cabled on 13 August the proposal that the USA build 3,000 fixed engine 200-hp Spads and 3,000 rotary engine fighters with the 150-hp Gnome. The decision of what type of rotary engine fighter would probably be made in a few days and would probably be the Spad monocoque (Spad 15).
  Pursuit airplanes must be two kinds. One type fixed engine with great horizontal speed and great diving speed, this is the fixed engine SPAD. Second type must have high ceiling and ability maneuver great altitude without losing altitude... You build as many rotary pursuit airplanes as fixed engine pursuit planes.

  In his report to the Chief Signal Officer of the Army, dated 15 August 1917, Maj R.C. Bolling, recommended that 1,500 of the new Spad (150 Gnome) or Nieuport (150 Gnome) be purchased for use from January 1918 by the AEF. The decision between New Spad and Nieuport to be made as soon as tests of New Spad are completed. There is time to await this because both types take the same engine. The New Spad was also recommended for production in the USA as a Fighting or Pursuit aircraft. The machine was now undergoing final tests.
  The report listed the following aircraft as "Types for American Production."
  - Advanced Trainer: Bristol Scout with 80 Le Rhone. Division or Corps d'Armee: Bristol Fighter with 200 Hispano.
  - Long range reconnaissance or day bombing: D.H.4 with Rolls Royce or some equivalent engine. (Fiat 300 has proved successful here).
  - Fighting or Pursuit (fixed engine): Spad with 200 HP Hispano.
  - Fighting or Pursuit (rotary engine): New Spad with 150 Gnome (This airplane is now undergoing final tests).
  - Night bombing: Caproni triplane with 3 Isotta Fraschini 270 HP engines or other equivalent engine.

  The "New Spad" that the US was so taken with was the Spad 15. It was one of four types proposed for the same engine that were in competition for production contracts. The US sent 17 draughtsmen and mechanics to the SPAD factory in France by early September. They were to assemble the second machine and prepare drawings before bringing the airframe back to the US as a production example. In the US the Thomas-Morse company was ordered on 8 September to prepare standardised production drawings.
  It was realised that aircraft and engines would have to be ordered in France and it was suggested that the following program be adopted for 1918 (see table on next page):
  The "New Spad" or the Nieuport was to be ordered as soon as tests of the "New Spad" were completed. As it turned out, the Spad 15 failed to gain a production contract and the USAS ended up with the Nieuport 28 as this was the only machine that could be supplied at the time.
  Around mid to late August 1917, Maj. Sewell, RFC liaison officer with the French, reported that the machine had not yet carried out its official trials. He noted that the machine had a span of 20 ft 7 in, a surface of 140 sq ft with the top plane having a chord of 3 ft 6 in and the bottom, 3 ft 3in. Weight was stated to be "about 12 cwt."

  Save for its rounded 3-ply fuselage and naturally different engine it greatly resembles the ordinary SPAD and does not appear to promise anything sensational in the way of climb or speed.
  The engine - of which large numbers have been ordered for use on MORANES, NIEUPORTS and possibly SPAD Monocoques - gives 159 hp at 1350 r.p.m. and weighs under 300 lbs.
  A peculiarity of this machine is that the large cone on the propeller boss is not attached to the propeller and accordingly does not turn - though free to do so - in the air.
  Two Vickers guns are fitted.

  The US Army's "Review of French Airplanes" of 23 October 1917, reported that the Spad Monocoque, Morane Biplane and Morane Monoplane, all of which are equipped with the Gnome 150 H.P. Monosoupape engine, have finished their tests.
  Referring to the Spad Monocoque the report noted that the Spad Monocoque with the 150 H.P. engine has been tested, and has done very poorly. Many persons were in favour of discontinuing work entirely on this machine, but a decision was finally made to permit the manufacture to rebuild the airplane with a different type of fuselage and to try it again in the future. The performance of this machine was a great deal poorer than either that of the Nieuport or Morane equipped with the same engine. It climbed to 2,000 metres in 5’ 40”; 3,000 metres in 9’ 35” and 5,000 metres in 27’ 25”. At 2,000 metres it made a speed of only 124 M.P.H. At 3,000 metres the speed was 122 1/2s M.P.H. and at 5,000 metres the speed was only 109 M.P.H."

  The comparison of the monocoque Spad 15 to the other aircraft using the Monosoupape engine is given in the accompanying table.
  The following comparison of the Gnome Monosoupape engine fighters was prepared by the British Aviation Commission in France.
  It appears that the machine was very manoeuvrable and achieved results similar to the Spad 13 despite the low power of its engine, and was thought to warrant further development.
  The British Aviation Commission wrote on 28 October 1917, that Messrs Spad were making another similar machine, but with 18 sq metres surface and designed to climb to 8,000 metres. This second Type 15 (15/2) had extended wings and a new tail. Herbemont abandoned the cone de penetration, and simplified the engine installation. The wings were still of near equal span and unstaggered but the interplane struts now slanted outwards and the centre-section cabane was redesigned.
  A third machine was built, 15/3, that was reported in January 1918 as "Monocoque construction (New and longer body) and powered by the "Rh.9R (180)"." It first flew in January 1918. Neither of these two examples was successful. A fourth modification of the basic design, 15/4, was apparently abandoned by 1 May 1918, before being built as it was not mentioned in a British report of that date. It was reported to have been designed for the 170 hp Le Rhone engine. However, a post-war report states that it did fly, making its first flight on 25 February 1918.
  A report of 29 November 1918, noted under the heading of "aircraft undergoing testing," that the 170-hp Rhone 9Ris motor for the Spad 15 biplane was being fitted to an earlier model of the type. However the previously mentioned British report on French Experimental Aeroplanes for 1 May 1918, recorded that the last report to the Technical Department was on 1 April and the SPAD 15 machines (XV.A and XV.B) had been abandoned. It is thought that the November report was associated with the efforts to get the correct performance out of the Le Rhone 9Ris engine, and although the aircraft may have been abandoned it could have been used for testing this engine.
  Maj J.P.C. Sewell reported for the British on French developments and in one report in April 1918, noted that the proposed 350 hp H-Suiza SPAD canon will be a genuine monocoque of seven or eight layers of wood built up round a mould like the pre-war Deperdussin and last year’s SPAD Monocoque. An advantage of such construction which is generally overlooked is that the number of drawings is considerably less than that of an ordinary fuselage.
  One of the drawbacks, of course, lies in the fact that any injury to the machine means a new hull.

  It appears that the development work on the Spad 15 was not wasted but was continued into the Spad 20.
  Post-war a civil version of the Spad 15 was produced for Rene Fonck and Charles Nungesser, the French "aces" who thought that a sporting machine with the performance of a scout would be required in the post-war civil aeronautical scene. Fonck's machine was given the registration F-ONCK while on Nungesser's black fuselage was painted his personal insignia - the Hussards de la Mort. This machine appears to have had the wings and tail painted with aluminium dope. Only these two 15/5 machines were constructed, the sportsman aviator was not to appear as predicted.
  As the late Jack Bruce wrote, The Spad 15.C 1 got precisely nowhere, although it was repeatedly modified.

  A post war document gives the following nomenclature to the Spad XV:
  - Spad XV1 fighter with petite cellue (small wings) and 160 cv Gnome (Monosoupape) First flight 31 July 1917.
  - Spad XV2 fighter with grande cellue (large wings) and 160 cv Gnome (Monosoupape) First flight August 1917.
  - Spad XV3 fighter with allonge and 160 cv Gnome (Monosoupape) First flight January 1918.
  - Spad XV4 fighter with allonge and 170 cv Le Rhone. First flight 25 February 1918.
  - Spad XV tourisme (sporting) with 80 cv. First flight 18 May 1919.
  The Spad XV1 to XV4 were single examples only, while an example of the XV was built each for Fonck and Nungesser.
  Source: Spad 15 Monoplace de chasse on de Moteur "Rhone” 80 cv. Dimensioned three-view drawing of the XV5 with details. Original source not quoted. Copy in RAF Museum J.M. Bruce Collection Box 16.


Proposed Purchases from French in 1918
Type Jan Feb Mar April May June Total
SPAD (200 Hispano) - 135 300 400 550 615 2000
New Spad (150 Gnome) 50 100 200 300 350 500 1500
Nieuport (150 gnome) 300 400 400 400 - - 1500
Source: "A Lesson in Timing," Aerospace Historian, Vol and date unknown. P.222. A reprint of Major Bolling's report.


Comparison of the Gnome Monosoupape Engine Fighters
Type Nieuport 28 Morane A.l Monoplane Morane AF Biplane Spad 15 Monocoque
Weights in Kg
   Empty 407 417 431 355
   Total load 228 228 228 260
   Total 635 645 659 615
Wing Area, m2 16 13 15% 16%
Climb to
   2,000 m 4' 40" 4'35" 4' 50" 5' 40"
   3,000 m 8' 15" 7' 45" 8' 10" 9'35"
   4,000 m 12' 00" 11' 50" 12'40" 16' 00"
   5,000 m 20'00" 17' 25" 20'30" 27' 25"
Speed in km/hr
   at 2,000 m 208 219 205 199.3
   at 3,000 m 206 215 200 1/2 197
   at 4,000 m 202 210 194 1/2 192
   at 5,000 m - - 185 -
Ceiling in m 6,000 6,800 6,000 6,000
Endurance in hrs 2 2 2 2
Source: TNA AIR1/2391/228/11/140. (The table accompanied a letter to HQ RFC of 28.10.1917.)

Spad 15 Monocoque Specifications
Source 1. 2. 3. XVa (15/1) 4 .XV5 (15/5)
Span, m 6.900 6.600 - 7.100
Length, m 5.000 - - 5.510
Height, m 2.300 - - 2.300
Chord upper, m - 1.250 - -
Chord lower, m - 1.100 - -
Incidence (both) - 3/4° - -
Wing Area, m2 16 1/2 13 1/2 (188 ft2) 16
Weights in Kg
   Empty - - 368 (811 lbs) -
   Engine group 160 - - -
   Glider 195 - - -
   Empty 355 - - -
   Fuel 79 - - -
   Oil 21 - - -
   Pilot 80 - - -
   2 Vickers & ammunition 80 - - -
   Military load - - 50 (110 lbs) -
   Total load 260 - - -
   Total 615 550 625 (1,378 lbs) -
Capacities in Itr
   Fuel - 100 - -
   Oil - 25 - -
Climb to
   2,000 m 5 min 40 - - -
   3,000 m 9 min 35 - - -
   4,000 m 16 min 00 - 13 min -
   5,000 m 27 min 25 - - -
Speed in km/hr
   at 2,000 m 199.3 - - -
   at 3,000 m 197 - - -
   at 4,000 m 192 - (118 mph) -
   Max - - - 170
Ceiling in m 6,000 - - 5,000
Endurance in hrs 2 - 2.5 -
Engine 165-hp Monosoupape 170 Monosoupape 150 Mono 80 Rhone
Source:
1) "Results of Preliminary Tests of 165 H.P. Monosoupape Engined Spad Monocoque with built up Tulip Wood Fuselage." TNA AIR1/2391/228/11/140.
2) Letter from British Aviation Commission, Paris, to Controller, Technical Dept, Air Board, London, dated 26 July 1917. TNA AIR 1/1069/ 204/5/1626.
3) French Experimental Aeroplanes, Monthly Aeroplane Report for May 1st, 1918, British Ministry of Munitions of War (Paris). Copy in RAF Museum J.M. Bruce Collection Box 46.
4) Spad 15 Monoplace de chasse on de Moteur "Rhone" 80 cv. Dimensioned three-view drawing with details. Original source not quoted. Copy in RAF Museum J.M. Bruce Collection Box 16.


Spad 15/2 Specifications
Source 1. XVb 2. XV/2
Span - 7.10
Length - 5.35
Height - 2.30
Weights in Kg
   Empty 360 (794 lbs) 368
   Military load 100 (220 lbs)* -
   Total 620 (1,367 lbs) 625 kg
Wing Area (188 ft2) 17.50 m2
Climb to
   2,000 m - 5.67 min
   4,000 m 13 min -
Speed in km/hr
   at 2,000 m - 199
   at 4,000 m 124 mph -
Endurance in hrs - 2.5
Engine 180 Rhone -
Notes: * There is an inconsistency in the figures as all the other figures for Ib/hp, etc., are the same as for the Type XVa (15/1).
Source:
1) French Experimental Aeroplanes, Monthly Aeroplane Report for May 1st, 1918, British Ministry of Munitions of War (Paris). Copy in RAF Museum J.M. Bruce Collection.
2) Green, W and Swanborough, G. The Complete Book of Fighters, Salamander Books, UK, 1994.