Main purpose and characteristics of the IAS Subsonic Wind Tunnel
IAS subsonic wind tunnel was designed as developmental tool that will help to study and optimize
aerodynamic and flight dynamic characteristics of the different types of UAV in sufficiently wide
range of subsonic velocities , reproducing experimentally all phases of flight. For this reason the
wind tunnel has two test sections. Large test section has interior flow surface dimensions 2,5m
(width); 2,0m(height); 5,0m (length). Maximum air speed in this test section is 30 m/sec. Small test
section has interior flow surface dimensions 2,0 m (width); 1,0 m (height);4,0 m(length).Maximum
air speed in small test section is 75 m/sec. Wind tunnel schematic drawing is presented in fig.1.
Wind tunnel has open circuit that permits to test UAV or aircraft model with internal combustion
engine.
Spatial uniformity of each test section velocity is within 1% with respect to mean flow velocity in
central 80% (core flow) of the test section .
Flow angularity is within  0,25 degree, measured with respect to the mean flow angle.
The core jet turbulence intensity is less than 0,5%.
A model support system is functional in the two test sections; it is mounted on the cart ,complete
with remote actuation systems and positioning indicators.
When installed in the large test section it is capable of the following motions:
Pitch: -15° to +30°.
Yaw:  30°.
When mounted in the small test section, the model support system is capable of the following
motions:
Pitch:  5 .
Yaw:  3.
The model loads and moments carried by the model support should be as follows:
Lift load:
2,2 kN
Side load:
0,4 kN
Axial load:
0,4 kN
Pitch moment: 270 Nm
Yaw moment:
15 Nm
Roll moment:
75 Nm
Motion rates and positioning accuracies for pitch and yaw systems are following:
Motion
Rate,°/sec
Readout accuracy, degrees
Pitch:
1,0
0,25
Yaw :
1,0
0,25
Instrumentation.
1.Loads and Moments.
IAS has its own original (patent pending) precise 6-component strain gauge balances that may be
manufactured in different sizes in correspondence with the individual model and experiment
requirements. Balances can be located inside the model structure.
2. Pressure distribution measurement.
The set of the Kulite miniature pressure sensor together with National Instrument data acquisition
hardware and software LabView provides precise measurement at stationary and non stationary
condition .
3.Thermoanemometry.
Modern 6-channel Dantec Dynamics anemometry system can be used for experimental
investigation of the flow near the model and in the wake.
4. Spatial velocity uniformity measurement and flow angularity measurements.
Modern Danetech system (Initium DTC) with several five hole pitot tube, 32 DTC pressure scanner
for 10”H2O and 20”H2O;
Several precise pressure sensors (GE Sensing) for measurements with five hole pitot tube, for
different range 0,1/0,5/10/50 mbar.
5. Data acquisition system
NI PXI system, based on fiber optics, up to 400 analog input 16 bit, digital I/O, analog output,
counters, regulated power supply, thermocouple input modules, etc…
NI CRIO system for real time data acquisition (FPGA system) up to 96 analog input 16 bit, digital
I/O, analog output, counters, relay modules, etc…
IAS capabilities that are supporting wind tunnel activity.
1. Design and manufacturing of the aerodynamic models and special experimental equipment.
IAS has experience and can provide CAD/CAM works using CATIA software . Different
test stands were designed and manufactured in IAS , including test stand of the internal
combustion engine with propeller and ducted fan, hovering flight dynamic test stand for the
VTOL unmanned air vehicle . IAS has experience and modern equipment for the
manufacturing aerodynamic models from composite materials: autoclave, furnaces, large 5axis CAM milling machine ,large ultrasound inspection machine, original, developed by
IAS, 5-axis CAM hot-wire cutting machine for precise manufacturing of complicated
aerodynamic and structural form model parts from polystyrene foam.
2. Custom design and manufacturing of the special instrumentation devices based on the strain
gauge technology, including original , developed by IAS inter-model and external 6component aerodynamic balances, propulsive device balances.
3. Custom design and manufacturing data acquisition and control system for aerodynamic
experiments and propulsive device testing. Fig… is presenting movable data acquisition and
control system that provided 3-D thrust vectoring control of the ducted fan propulsive
device and simultaneous measurement of the all 6 components of the forces and moments
from both lateral sides of propulsive device . The system use National Instrument hardware
and software together with custom designed and manufactured amplifiers, terminal boards
and customized software subroutines.
4. Experimental data treatment and mathematical model parameter identification.