Messerschmitt. От M.25 до M.28

Обозначение M.25 получил нереализованный проект легкого самолета. M.26 - так обозначался трехместный высокоплан с закрытой кабиной, построенный только как прототип.
   Самолет M.27 стал развитием M.23. На варианте M.27a стоял звездообразный мотор Siemens SL-12 мощностью 110 л.с. За M.27a последовала партия из 10 самолетов варианта M.27b с моторами Argus As 8 мощностью 120 л. с.
<...>

Flight, October 1928

THE BERLIN AERO SHOW 1928

The B.F.W. Messerschmitt Light 'Planes

   The Bavarian Aircraft Works of Augsburg exhibit two machines in the light 'plane class. Of these one is a two-seater biplane with Siemens S.H.11 engine, and the other is a low-wing monoplane two-seater with 20 h.p. Mercedes engine.
<...>
   The B.F.W. M.23 is of the low-power, low-wing monoplane type made familiar in recent years by the Klemm Daimler machines. Like these, it is fitted with the 20 h.p. Mercedes engine, and the ply-wood covered fuselage has its decking in the form of a sharp-ridged "roof."
   The wings, which taper in plan form and thickness, are of the typical Messerschmitt single-spar construction, and this fact has been made use of in arranging the folding. The two wing halves are fitted to the fuselage by three quick-release devices, two of which are situated at top and bottom respectively of the main spar, the third being placed farther back in the section. After releasing the three catches the wing can be lifted off and placed on edge alongside the fuselage, where there are small brackets to support it.
   The exhibition machine is fitted with the 20 h.p. Mercedes flat twin engine, but the A.B.C. "Scorpion" Mark II can also be fitted and gives a considerably better performance. Furthermore, it is stated that the structural strength of the machine is such that for special purposes an engine like the Armstrong-Siddeley "Genet" can be used.
   The B.F.W. M.23 has the following main dimensions: length o.a., 6-9 m. (22-6 ft.); wing span, 11-83 m. (38-8 ft.); wing area, 14 sq. m. (151 sq. ft.). The tare weight is 200 kg. (440 lbs.) and the permissible load 210 kg. (462 lbs.), giving a total loaded weight of 410 kgs. (902 lbs.). The maximum speed with Mercedes 20-h.p. engine is given as 135 km./h. (84 m.p.h.), and the cruising speed as 110 km./h. (68 m.p.h.). the ceiling is 3,500 m. (11,500 ft.), and the range 500 km. (310 miles).

Flight, June 1929

OLYMPIA AERO SHOW 1929

Bayerische Flugzeug Werke

   The B.F.W. M.23, designed like a number of other recent B.F.W. machines, by Herr Messerschmitt, is a two-seater low-wing monoplane of wood construction, very similar in its general conception to the familiar Klemm monoplanes, but designed for engines of rather greater power, such as the "Cirrus" or "Genet." The wings are quickly detachable from the fuselage for housing or transport purposes. The undercarriage is of the divided type. The M.23 is a nice straightforward design, but shows no unusual features calling for comment.
   The dimensions, &c, of the M.23 are as follows: Length, 6-45 m. (21-2 ft.); wing span, 11-8 m. (38-7 ft.); wing area, 14-5 sq.m. (156 sq.ft.). When fitted with the Cirrus engine the machine has a tare weight of 320 kg. (705 lbs.). As the gross weight is 570 kg. (1,255 lbs.), the disposable load becomes 250 kg. (550 lbs.).
   The full speed is given as 175 km./h. (108 m.p.h.) and the landing speed as 68 km./h. (42 m.p.h.). The climb to 1,000 m. (3,300 ft.) occupies 5 mins. 30 secs., and the ceiling is 5,800 m. (19,000 ft.).

Flight, March 1930

THE B.F.W. M.23
A German Light 'Plane with Many Variations

   DESIGNED by Herr Dipl.-Ing. Willy Messerschmitt, and built by the Bayerische Flugzeug Werke, of Augsburg, Germany, the type M.23 two-seater light 'plane is available in a variety of forms, or rather with a choice of different power plants. The standard engine plate has been designed for the A.B.C. "Scorpion," but the machine can be supplied with any of the following engines: The Armstrong Siddeley "Genet," the A.D.C. "Cirrus II," or the Siemens SH 13. Either of these engines can be fitted without material changes to the machine being necessary. The range covered is not, however, exhausted by this list. By making small modifications, the machine can be had with more powerful engines, such as the "Cirrus III," or even the "Cirrus-Hermes."
   For identification purposes the machine is known, when fitted with either the "Scorpion" or the Salmson engine, as the type M.23A, and when fitted with either of the more powerful engines it is known as the M.23B. The main data relating to weight, performance, etc., of the machine when fitted with the different power plants have been collected in a table. It will be noted that in all its versions the M.23 has a very good ratio of useful load. Thus, in the "Scorpion" version, the useful load is exactly equal to the tare weight of the machine. The tare weight itself is low in all versions. So much so that even the "Hermes"-engined machine is well within the F.A.I, classification of light 'planes. Exactly how the structure weight has been kept down to such a low figure is not clear, but it may be recollected that the machines exhibited by the B.F.W. Company at the Berlin Show were all of low tare weight compared with their gross weight. The German system of stressing, load factors, etc., is different from ours, but it would scarcely be safe to say that it is inferior. We believe we are right in stating that the condition of nose diving at terminal velocity does not have to be met by German designers, but that the stresses thus arising are taken care of by other assumptions. However, that may be, it is interesting to reflect that the M.23B fitted with the "Hermes" engine would, for instance, be eligible for the International Touring Competition to be held this summer. As this version has a top speed of 115 m.p.h, (185 km./h,), it might conceivably come very close to gaining the full 195 points awarded for an average speed of 175 km./h. (108 m.p.h.) around the Circuit of Europe.
   Constructionally the M.23 is of simple type, with a plywood-covered fuselage and a wooden cantilever wing, partly fabric-covered and partly plywood-covered.
   A tubular mounting carries the engine, and the engine compartment is separated from the fuselage proper by a fireproof bulkhead. The petrol tank is housed in the deck fairing, aft of the engine bulkhead, and is placed sufficiently high to give direct gravity feed. The central portion of the fuselage is a light framework of spruce, covered with plywood, and contains the two seats in tandem The rear portion of the fuselage is of somewhat lighter, but similar construction, and terminates at the rear in a horizontal knife's edge.
   The cantilever wing is of wood construction, with a single main spar and an auxiliary spar, the leading edge being covered with plywood to form, with the spar, a plywood tube of approximately "D" section, a form of construction which has become popular in Germany for gliders, and which is very effective in resisting torsion. The wings have a pronounced taper, both in chord and thickness. Folding is provided for, one of the attachments to the fuselage being in the form of a universal joint which permits the wing, when the other attachments are released, to be tilted up with its chord vertical, and folded back along the sides of the fuselage.
   The undercarriage is of the "split" type, with axles of chrome-nickel steel tubing hinged to a central pyramid. The tail surfaces are of the cantilever type, i.e., without external bracing, and the fin and tail plane are covered with plywood. All control cables are led through the interior of the fuselage, none of the cranks being exposed.
   The two cockpits are fairly roomy, and are normally equipped with dual controls and instruments. When the machine is not to be used for school work the front control stick can be removed.
   Aerodynamically, the M.23 looks a clean and efficient design. To British eyes, however, the placing of the rudder wholly above the fuselage, with the tail plane and one-piece elevator below it, seems to be an undesirable feature and somewhat likely to render the rudder control at large angles less effective than we are accustomed to, owing to the "blanketing" of the rudder which the horizontal surfaces below it may be supposed to bring about.
   The placing of the two seats, very close together, is doubt less good for instructional purposes, but their separation, the front cockpit being moved farther forward and the rear cockpit farther aft, would have improved the view from both. Even as it is, however, the view is by no means bad, and the separation of the cockpits would have necessitated a longer fuselage.
   Herr Messerschmitt is one of the rising German designers, and the B.F.W. firm, under his technical direction, has proved itself an energetic and enterprising concern. Doubtless, therefore, several B.F.W. machines will be taking part in the International Touring Competition, and in view of that fact we have thought that British readers would be interested to learn what sort of machines the British competitors are likely to be "up against."