Stength Test Laboratory (STL)

These tests of aviation or other constructions are available on Strength Test Laboratory:

In the base of STL is power frame of tests hall consisting of power ceiling, power floor and vertical connecting columns. The power floor and ceiling enable fastening of object tested everywhere in the STL. Construction of power and equipment of STL enables testing of several objects simultaneously, according to their sizes. Equipment of remote control of STL loading systems and the pumping station are mounted in separate rooms. A vertical power wall is designed for testing of objects for which console fastening is necessary.

TECHNICAL DATA OF STL
Area of static tests hall 720 m2 (30x24 m)
Height of power ceiling 9,4 m
Height till crane bridge 15,7 m
Ceiling height 20 m
Max. size of airplane tested
a) wing span 26 m
b) fuselage length 18 m
Power of stationary hydropumping station 200 kW
Operational pressure in hydrosystem 20 Mpa
Range of loading forces created for one excitation point 5 - 100 kN
Quantity of constructions tested simultaneously not more than 4
Max. frequency for cyclic loadings (with small amplitudes) 0,5 Hz
Max. move amplitude of construction in cyclie operation conditions 2 m

Equipment for testing

Tested object is attached to power floor by the help of modular fastening equipment. Loading forces are created by the help of hydrocylinders connceted to stationary hydrosystem. Hydrocylinders can be attached in every place on power floor or ceiling where it is necessary. Stands of static loadings on wings and body have correction system for applying point of force which enables to maintain the direction of applied force optimally when moves of force applying point of a construction being tested are large. Lever system is used for distribution of excitation force of hydrocylinders and loading of a construction. They are assembled of metal profiles and rods.

Recorder of sailplane flight parameters.

Usage field

Recorder's (R) purpose is recording and acucumulating of paramaters of dynamic sistems in floppy disk. It might be used in airplanes, including sailplanes, or in ground eguipment, where a direct connection of information transmitting channels with its processing system or a computer is not available.

Constructions

R consists of a microprocessor signal input unit, floppy disk drive, remote control panel and feeder. Microprocessor unit and disk drive are connected together. System of microprocessor unit allows recording of 1, 2 or 12 synchronous signals. Capacity of recorded information on one floppy disk depends on quantity of loaded channels and chosen on control panel frequency of signal discreetizing. Time of record is controlled discreetly by setting 10 s or 20 s. This information is saved into standard 1,44 MB floppy disk. Structural scheme of R is shown in Fig. 1, where A1, A2,….A12 are accelerometers or other transformers.

TECHNICAL DATA OF RECORDER
Quantity of points measured 12
Range of signal frequency 0,1 - 250 Hz
Frequency of discreetizing 200, 500, 1000 Hz
Continuous measurement time of signal 10, 20 s
Time of wrinting of information into floppy disk till 15 s
Feeder battery 12 V
Size of recorder
a) microprocessor and disk drive 254x260x150 mm
b) feeder 180x130x70 mm
Total mass 8,2 kg

R is created in cooperation with specialists of Kaunas Technological University. Usually shape of sailplane fuselage is chosen to ensure minimum aerodynamic drag. So there is not much free room inside the fuzelage. For sailplane flight testing (e. g. flutter) it is important to locate equipment recording flight parameters in a sailplane. Since R contains 3 units of not large size they can be easily located in existing free space in the fuselage. Control panel itself fits in on an instrument panel easily.

During tests R records flight airspeed, height and, according to flight task, oscillations of saiplane parts (wing, stabilizer and others) or parameters of saiplane stability and handling. Recording of acceleration of fin oscillations is shown in Fig. 3 when excitation impulse is given by ailerons at saiplane airspeed V=300 km/h. Damping of excitated oscillations of fin is noticeable, according to it a logarithmic decrement of oscillations damping is determined.