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Caspar airliner C 35 Priwall.
The new C 35 "Priwall" commercial aircraft from Caspar-Werke
A.-G., Travemünde, is a ten-seater land aircraft that was ordered
by Deutsche Lufthansa in November
last year. The 500/600 hp
BMW VI engine was prescribed by the customer as the drive. Of the conditions of acceptance, the following are
of particular interest: closed room for
the two guides, comfortable cabin for 8 persons, toilet, luggage
compartment, fuel for 5 hours; with a flight weight of about 4000 kg, a
cruising speed of 160 km, a maximum speed of
175 km, a climbing ability of 1000 m in 9 minutes and 2000 m in
29 minutes, good flight characteristics.
The required conditions were met in the single-stem C 35 fuselage biplane, built in tubular steel and wood
.
The biplane, an exception in German air traffic, was chosen because it has lighter wings, a considerably smaller
wingspan and shorter fuselage length compared to an equivalent
monoplane, and thus requires less floor space forits storage. The storage costs of an aircraft are
calculated at home and abroad according to the area of the longest length X the largest width. Further advantages
result from the design for shipping by rail or ship. Tubular steel and wood
were used as building materials, as various reasons made this construction method appear to be particularly
advantageous.
It is well known that in order to become more profitable, air transport always demands 'cheaper' from
the construction industry, and since the construction costs of mixed construction are much lower than those of
all-metal aircraft, the former was chosen. The fact that aircraft of this type are also cheaper in terms of
repair costs has been shown by the statistics of the air transport and insurance companies
in recent years. One point that is much disputed is the service life of all-metal
aircraft. To those who say that the longer service life has been proven, it must be pointed out
that, according to the publication of Deutsche Lufthansa, the technical obsolescence rate of
land aeroplanes is at present about 3 years, and that aeroplanes built of tubular steel and wood
have a service life of five years or more. The performance of the aircraft of
both types can be considered the same.
The superstructure, as well as the cabin, can be seen in the following illustrations.
The passenger compartment (cabin) with a headroom of 1.90 m accommodates eight comfortable leather armchairs with adjustablebackrests, each of which stands against one of the eight windows. The 50X50 cm windows can be retracted by cranks and are completely airtight. The cabin with linoleum flooring, with natural leather on the walls up to window height and washable white link rust above, with luggage nets and heating makes a dignified, distinguished impression in the well-coordinated colors. The well-regulated heating systemis followed in the familiar way by hot air from the exhaust of the engine. The door to the driver's cab is designed as a cabinet door, in which drinks, biscuits and chocolate can be carried.
The two-seater driver's cab in front of the cab, which can also be heated, is completely closed. The top is made of cellon; the front and side sliding windows made of Kinon glass are easy to open and close. All important control levers are positioned in such a way that they are easily accessible from both seats. The seats of the driver's cab are adjustable in height and length. A compressed air cylinder for starting the engine is located under the right driver's seat. The instrumentation prescribed by the customer includes the following equipment: altimeter, dynamic pressure gauge, rotary counter, Askania gyroscope, driver's compass lying above the control column. Directional compass in the middle of the driver's cab, on-board clock, oil and fuel level indicator, oil and cooling water thermometer and oil pressure gauge. Carburetor fire extinguisher and electric switchboard complete the setup. The electricity is generated by an Eisemann alternator with a pressure propeller. The accumulator is located under the driver's cab. The aircraft has the prescribed four position lamps, further lighting in the cabin and toilet as well as lamps on the compasses. Furthermore, a cable roller country lamp is planned in the driver's cab.
In front of the driver's cab, the BMW VI engine lies on the tubular steel frame firmly attached to the fuselage. The fairing plates are arranged in such a way that all important parts of the engine are easily accessible. The engine cowling in front of the driver's cab slopes forward in such a way that you have the impression of sitting in a pulpit from which the view extends undisturbed over the entire area. The NKF radiator is located under the engine. A four-bladed wooden construction from the Heine company was chosen as the propeller. Behind the cabin is the toilet, which is equipped with a door closing on two sides in such a way that part of it can be used as a passage when getting in and out of the cabin. This is achieved by the fact that it is very spacious on the one hand, and that on the other hand the cabin compartment has a second locking door in front of the boarding door in flight. Behind the toilet is the luggage compartment, which is accessible through a two-part door from the left side - the boarding side.
The chassis has a continuous axle and struts at the front. The rear struts are unsprung. Wheels with a diameter of 1.25 m and a tire width of 0.25 m were prescribed. On request, the aircraft can be delivered with a split axle. The upper supporting deck, resting on the canopy, is continuous, the two lower supporting decks adjoin the hull: both are made entirely of wood and fabric. The entire fuel is located in two containers in the canopy part of the upper support deck. The supporting decks, which are connected by a J-stick and braced with streamlined wire, are staggered in such a way that the front spar of the lower support deck is located under the rear beam of the upper wing deck. Both the upper and lower wing decks have ailerons. The tail unit is designed in the tried and tested form with plywood-planked elevator fin, steel tubular elevator, rudder and keel fin. The aircraft, which was a successful design by the technical director of Caspar-Werke, engineer Herrmann, carried out his factory flights up to the DVL test under the leadership of the well-known German Lufthansa pilot Walter Noack in a very short time. There were no more special changes from the factory flights, proof that the design was correct from the beginning.
The official results of the examination result from the compilation attached at the end and prove that the performance required by Deutsche Lufthansa has been substantially exceeded.
The aircraft will be put into Deutsche Lufthansa's flight operations. We hope that this newest aircraft of the German Air Fleet, which is characterized by low acquisition costs (correspondingly low insurance, interest and amortization rates), low repair costs, low storage costs and high performance with good flight characteristics, will also prove itself in continuous operation.
Size and performance specifications of the C 35, construction no. 7015: length 13.27 in, wingspan 16.72 in, required gate height 5 m, area size 70 m2, engine BMW VI 500,600 hp.
For other aircraft, 215 km and improved climb performance are guaranteed by the company. The C 35 model is also supplied as a two-watch immersion seaplane. (10 seats, 185 km)