Flight, November 1924

THE "HOLLAND" LIGHT PLANES

   SOME of our readers will, no doubt, remember our description - which appeared in FLIGHT for November 29, 1923 - of the Carley Light Monoplane, produced by a Dutch Limited Company, at s'-Gravenhage, the principals of which were Mr. J. D. Carley and Mh. H.v.d. Kwast. Since our last description further developments have taken place, and the company, now known as Vliegtuig-Industrie "Holland," has produced two new types.
   One of these, the "Holland H-2," is a monoplane on similar lines to that referred to above, from which, as may be seen from one of the accompanying illustration, it differs as regards general appearance only in minor details - mainly in the undercarriage. The engine fitted in this machine is, as before, a 3-cyl. 25 h.p. Anzani (air-cooled).
   The second machine, the "Holland H-1," is a biplane of more or less distinctive design, and being, perhaps, the more interesting of the two, we propose confining our remarks to a brief description of this machine. Before doing so, however, we will give the principal characteristics of the monoplane H-2, which are as follows :- span, 25 ft. 3 ins.; O.A. length, 15 ft. 10 ins.; wing area, 109-75 sq. ft.; weight empty, 374-8 lbs.; weight laden, 650-5 lbs.; weight per h.p., 26-4 lbs.; weight per sq. ft., 5-8 lbs.; speed range, 25-74 m.p.h.
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Flight, December 1924

The Paris Aero Show 1924

THE PANDER LIGHT MONOPLANE

   REGARDED by many as the prettiest and best-finished aeroplane in the Grand Palais, the little monoplane exhibited by H.Pander en Zonen, of the Hague, Holland, is a perfectly normal cantilever monoplane as regards its general lines, but the forms of construction adopted are somewhat unusual, and the method of carrying them out, in other words the workmanship is highly commendable. It is not claimed that the Pander is a particularly cheap machine, but it is a very light machine as regards structure weight, and as the factor of safety is high (about 7 1/2) it is to be assumed that the weight has been reduced by the most painstaking attention to detail.
   Three-ply is extensively used in the construction of the Pander monoplane, and where the usual sheet three-ply is not used laminated or multi-ply is employed in its place. Thus the fuselage has formers of laminated construction, something after the fashion of the familiar hoop, and although in themselves light, some are spindled out to a V- or U-section in order further to reduce weight. The longerons, of which there are four main ones and one at top and bottom of cross section are notched into the hoops, which are swelled and reinforced at these points. The very light skeleton thus formed is then covered with thin three-ply, and never in all our experience have we come across a finer example of ply-wood covering It is true that the fuselage of the show machine was painted, but even so one would have expected to be able to see or at any rate, feel a joint somewhere. Yet none was to be discovered Not only so, but nowhere was the three-ply covering found to buckle, as thin three-ply usually does. The whole surface was perfectly smooth on sides as well as on upper and lower fairings. The actual sides are flat, but the change into the deck and floor fairings is so gradual that on casual inspection one fails to notice that there is a flat portion, the section giving the appearance of being perfectly elliptical.
   The wing construction is entirely in wood, there being two spars as in ordinary practice. The front one, however, forms a box in conjunction with the ply-wood covered leading edge, and struts arranged in a rather peculiar way serve to stiffen the cantilever wing against torsion.
   The V undercarriage is built up of streamline steel tubes, the upper ends of which are bolted to the sides of the fuselage, the load being distributed by steel straps running under the belly of the fuselage, as shown in our sketch. The same fitting serves for the wing attachment, which is in the form of a long U-bolt passing through the wing and anchored at the top with locknuts and a short yoke. The wing, incidentally, is in a single piece, the spars passing across the fuselage, and the coaming around the cockpit being placed in position after the wing is in place. Owing to the U-bolt arrangement, however, the wing is readily removed.
   It is not proposed to give a very detailed description of the Pander light monoplane here, as we hope to deal with it more thoroughly in a subsequent issue of FLIGHT. The main characteristics may, however, be of interest: Length, o.a., 4-95 m. (16 ft. 3 ins.); span, 8 m. (26 ft. 3 ins.); wing area, 10-8 sq. m. (116-3 sq. ft.); weight of machine empty, 175 kgs. (385 lbs.); weight loaded, 280 kgs. (616 lbs.); engine, 30 h.p., Y-type Anzani; power loading, 20-5 lbs./h.p.; wing loading, 5-3 lbs./sq. ft.; maximum speed, approximately 130 km./h. (81 m.p.h.); landing speed, 40 km./h. (25 m.p.h.). One of the Pander light monoplanes was flying at le Bourget during the Paris Aero Show, and several famous French pilots tried it and expressed themselves highly delighted with its performance and handling.

Flight, February 1925

THE PANDER LIGHT MONOPLANE
30 H.P. "Y"-Type Anzani Engine

   IN our issue of December 25, 1924, containing a report of machines exhibited at the Paris Aero Show, we published a brief description and a few sketches of the Pander light monoplane. This machine, which was perhaps one of the prettiest in the Grand Palais, and was exceptionally well finished, has now been built in several examples, one of which was flying daily at Le Bourget during the Paris Show, where it created a very favourable impression. This week we give a slightly more detailed description of the machine, which is being built by Pander & Zonen, of the Hague, Holland.
   It may bee argued that the Pander, with an engine of considerably more than 1,100 c.c. capacity, is not a light 'plane according to British standards. It is, however, a low-power machine and may be classed as a light 'plane, at any rate until some official ruling on the question of what constitutes a light 'plane is given.
   In general design the Pander is a perfectly straightforward monoplane of the cantilever type, and except for pointing out its very clean lines, the aerodynamic design does not appear to call for comment. Careful streamlining has been effected wherever possible, but neither enclosed undercarriage nor any other feature peculiar to "motor-assisted gliders" is to be found, and the machine is normal in every way.
   The construction is of interest, however, because of the painstaking care bestowed upon details, which has resulted, not in a cheap machine - for, as Mr. Pander very rightly claims, one cannot build a very cheap machine which is also very light - but a machine in which structure weight has been reduced to a very low figure indeed. The fuselage is a monocoque consisting of light longerons and hoops with a covering of three-ply wood. Actually the fuselage is flat-sided, but the turtle back and bottom fairings merge into it so gradually that one receives the impression that the section is elliptical. The ply-wood covering is exceptionally neatly applied, and in spite of its thinness shows no buckling. The hoops are of laminated construction, and several of them are spindled out for lightness.
   The pilot's cockpit is placed between the wing spars, which rest on the top longerons, the curved coaming around the cockpit being put on after the wing is in place. Controls of the usual type are provided, except that in place of the usual rudder bar two tubular pedals with heel rests and toe guards are fitted. Thus in the small space available the angularity of a short rudder bar is avoided. A longitudinal rocking shaft carries cranks for the aileron controls, and a smaller tube runs from the joy-stick to a "bloater," from which wires run to the elevator. This tube is provided with a ball-and-socket joint at each end so that lateral movement of the control column does not interfere with the elevator control. The latter, incidentally, is operated by central cranks, the upper of which works inside the vertical fin and the lower inside the stern portion of the fuselage.
   The monoplane wing is in one piece, and, as already mentioned, rests on the top longerons of the fuselage, each spar being secured by long "U-bolts" carrying yokes above the spar. The wing spars are of box section, with spruce flanges and three-ply walls. The front spar is of somewhat unusual arrangement and forms a box with the ply-wood covering of the leading edge. The curved wing tip is fairly thick, and is built up of a great number of laminations afterwards spindled out to approximately a semi-circular section. One of these wing tips was exhibited on the Pander stand at the Paris Show, and was surprisingly light, probably not more than 5 or 6 ozs. The tail is of similar construction to that of the wing, and is shown in one of the accompanying photographs.
   The three-cylinder Y-type Anzani engine is neatly cowled in and drives a small tractor airscrew. Petrol is carried in two small tanks in the wing, one on each side of the fuselage, and supply the carburettor by gravity feed.
   Streamline steel tubes form the members of the undercarriage, the two vees being hinged at the top to the sides of the fuselage, the load being distributed over a large area by steel bands running under the belly of the fuselage. The axles are hinged under the floor of the body, the hinges being covered with a streamline fairing. Rubber shock absorbers secure the outer axle ends to the angle of the vees.
   The tail skid is mounted on and moves with the rudder, and is sprung by an enclosed coil spring. The whole fitting is shown in a photograph. The workmanship of the specimen exhibited at Paris was, as already stated, excellent, and if the same quality is maintained in the production machines there should be a ready sale for the Pander light monoplane, especially as we understand the price is very reasonable.
   Following are the main characteristics of the Pander light monoplane: Length overall, 4-95 m. (16 ft. 3 m.); wing span, 8 m. (26 ft. 3 in.); wing area, 10-8 sq. m. (116-3 sq. ft.); weight of machine empty, 175 kgs. (385 lbs ); weight fully loaded, 280 kgs. (616 lbs.); top speed, 130 kms./h. (81 m.p.h.); landing speed, 40 kms./h. (25 m.p.h.). Power loading, 20-5 lbs./h.p.; wing loading, 5-3 lbs./sq. ft.